Another Try at Wall Offset Tracking, Part II

Posted 22 June 2021

In my previous post on this subject, I described my effort to improve Wall-E2’s wall tracking performance by leveraging controlled-rate turns and the dual VL53L0X ToF LIDAR arrays. This post describes an enhancement to that effort, aimed at allowing the robot to start from a non-parallel orientation and still capture and track a desired wall offset.

The previous post showed that when starting from a parallel orientation either inside or outside the desired wall offset, the robot would make a turn toward the offset line, move straight ahead until achieving the desired offset, then turn down-track and start tracking the desired offset. The parallel starting condition was chosen to make things easier, but of course that isn’t realistic – the starting orientation may or may not be known. In previous work I created an entire function ‘RotateToParallelOrientation()’ to handle this situation, but I would rather not have to do that. It occurred to me that I might be able to eliminate this function entirely by utilizing the known characteristics of the triple-VL53L0X array. The linear array exhibits a definite relationship between ‘steering value’, (the difference between the front and rear sensor values, divided by 100) and the off-perpendicular orientation of the array. At perpendicular (parallel orientation of the robot), this value is nominally zero, and exhibits a reasonably linear relationship out to about +/- 40º from perpendicular, as shown in the following plot from this post from a year ago.

Array distances and steering value for 30 cm offset. Note steering value zero is very close to parallel orientation

As can be seen above, the ‘Steering’ value is reasonably linear, with a slope of about -0.0625/deg. So, for instance, the calculated value for an offset of 30cm would be -0.0625*30 = -0.1875, which is very close to the actual plotted value above for 30º

So, it should be possible to calculate the off-perpendicular angle of the robot, just from the measured steering value, and from that knowledge calculate the amount of rotation needed to achieve the desired offset line approach angle.

The desired approach angle was set more or less arbitrarily by

cutAngleDeg = WALL_OFFSET_TGTDIST_CM - (int)(Lidar_LeftCenter / 10.f);

1	cutAngleDeg = WALL_OFFSET_TGTDIST_CM - (int)(Lidar_LeftCenter / 10.f);

and this assumes an initial parallel orientation (i.e. 0º offset in the above plot). If, for instance, the initial steering value was -0.1875, indicating that the robot was pointing 30º away from parallel, then the code to compute the total cut (assuming we are tracking the wall on the left side of the robot) would look something like this:

TrackLeftWallOffset()
{
	...
	...
	...
	
	//modify the cut angle based on robot's actual orientation
	if(cutAngleDeg < 0) //robot inside desired offset distance
	{
		adjCutAngleDeg = cutAngleDeg + getSteeringAngle(LeftSteerVal);
	}
	else //robot outside desired offset distance
	{
		adjCutAngleDeg = cutAngleDeg - getSteeringAngle(LeftSteerVal);
	}
	...
	...
	...
}
SpinTurn((adjCutAngleDeg < 0),adjCutAngleDeg);

double getSteeringAngle(double steerval) 
{
	double val = steerval / -0.0625; //e.g. for steerval = -0.1875, returns +30
}

TrackLeftWallOffset()

{

...

//modify the cut angle based on robot's actual orientation

if(cutAngleDeg < 0) //robot inside desired offset distance

{

adjCutAngleDeg = cutAngleDeg + getSteeringAngle(LeftSteerVal);

}

else //robot outside desired offset distance

{

adjCutAngleDeg = cutAngleDeg - getSteeringAngle(LeftSteerVal);

}

...

}

SpinTurn((adjCutAngleDeg < 0),adjCutAngleDeg);

double getSteeringAngle(double steerval)

{

double val = steerval / -0.0625; //e.g. for steerval = -0.1875, returns +30

}

So, for example, if the robot’s starting orientation was offset 30º away from the wall, and 20cm inside the desired offset line of 30cm, we would have:

cutAngleDeg = WALL_OFFSET_TGTDIST_CM – (int)(Lidar_LeftCenter / 10.f);

cutAngleDeg = 30 – 10 = 20

adjCutAngleDeg = cutAngleDeg – 30 = -10º, so the robot would actually turn 10º CCW (back toward the wall) before starting to move to capture the desired offset line.

If, on the other hand, the robot was starting from outside the desired offset (say at 60cm), but with the same (away from wall) pointing angle, then the result would be

cutAngleDeg = WALL_OFFSET_TGTDIST_CM – (int)(Lidar_LeftCenter / 10.f);

cutAngleDeg = 30 – 60 = -30

adjCutAngleDeg = cutAngleDeg – 30 = -30 – 30 = -60º, so the robot would actually turn 60º CCW (back toward the wall) before starting to move to capture the desired offset line.

26 June 2021 Update:

I modified my test program to just report the rear, center, and front VL53L0X distances, plus the steering value and the computed off-parallel angle, using the -0.0625 slope value obtained from the above plots. Unfortunately, the results were wildly unrealistic, leading me to believe something was badly wrong somewhere along the line. So, I redid the plots, thinking maybe the left side VL53L0X sensors were different enough to make that much of a difference. When I plotted the steering value vs off-parallel angle for 10, 20, 30 & 40cm wall offsets, I got a significantly different plot, as shown below:

As can be seen in the above plot, the slope of steering values to off-parallel angles is nice and linear, and also quite constant over the range of wall offset distances from 10 to 40 cm; this is quite a bit different than the behavior of the right-side sensor array, but it is what it is. In any case, it appears that the slope is close to 1.4/80 = 0.0175, or almost twice the right-side slope derived from the previous right-side plots.

Using the value of 0.0175 in my GetSteeringAngle() function results, and comparing the calculated off-parallel angle with the actual measured angle, I get the following Excel plot.

As can be seen in the above plot, the agreement between measured and calculated off-parallel angles is quite good, using the average slope value of 0.0175.

The above plot shows the raw values that produced the first plot.

So, back to my ‘FourWD_WallTrackTest’ program to develop Wall-E2’s ability to capture and then track a particular desired offset. In my first iteration, I always started with Wall-E2 parallel to the wall, and calculated an intercept angle based on the difference between the robot’s actual and desired offsets from the near wall. This worked very nicely, but didn’t address what happens if the robot doesn’t start in a parallel orientation. However, when I tried to use the data from a previous post, the results were wildly off. Now it is time to try this trick again, using the above data instead. Because the measured steering value/off angle slopes for all selected wall offsets were essentially identical, I can eliminate the intermediate step of calculating the appropriate slope value based on the current wall offset distance.

So, I modified my ‘getSteeringAngle()’ function to drop the ‘ctr_dist_mm’ parameter and to use a constant 0.0175 slope value, as shown below:

double getSteeringAngle(double steerval)
{
	//Purpose:  Convert a steering angle into the equivalent off-parallel orientation in degrees
	//Inputs:
	//	steerval = double value denoting current steering value
	//	Notes:
	//	06/27/21 now steering_val/off_angle slope is a constant 0.0175
	const double slopeval = 0.0175;
	double offparalleldeg = steerval / slopeval; //e.g. for steerval = -0.187 @ 10cm offset, returns +21deg
	//mySerial.printf("getSteeringAngle(%d, %2.4f): slopeval = %2.4f, res %2.2f\n", ctrdist_cm, steerval, slopeval, offparalleldeg);
	return offparalleldeg;
}

double getSteeringAngle(double steerval)

{

//Purpose: Convert a steering angle into the equivalent off-parallel orientation in degrees

//Inputs:

// steerval = double value denoting current steering value

// Notes:

// 06/27/21 now steering_val/off_angle slope is a constant 0.0175

const double slopeval = 0.0175;

double offparalleldeg = steerval / slopeval; //e.g. for steerval = -0.187 @ 10cm offset, returns +21deg

//mySerial.printf("getSteeringAngle(%d, %2.4f): slopeval = %2.4f, res %2.2f\n", ctrdist_cm, steerval, slopeval, offparalleldeg);

return offparalleldeg;

}

With this modification, I was able to get pretty decent results; Wall-E2 successfully captured and tracked the desired offsets from three different ‘inside’ (robot closer to wall than the desired offset) orientations, as shown in the following short videos:

‘Inside’ capture, with initial orientation angle > desired approach angle

‘Inside’ capture with initial orientation angle < desired approach angle

‘Inside’ capture with negative initial orientation angle

04 July 2021 Update:

After succeeding with the ‘inside’ cases, I started working on the ‘outside’ ones. This turned out to be considerably more difficult, as the larger distances from the wall caused considerable variation in the VL53L0X measurements (lower SNR?), which in turn produced more variation in the starting and ‘cut’ angles. However, the result does seem to be reasonably reliable, as shown in the following videos.

‘outside’ capture with initial outward angle

‘outside’ capture with initial inward angle

‘outside’ capture with small outward angle.

05 July Update:

After getting the left-side tracking algorithm working reasonably well, I ported the ‘TrackLeftWallOffset()’ functionality to ‘TrackRightWallOffset()’. After making (and mostly correcting) the usual number of mistakes, I got it going reasonably well, as shown in the following short videos:

Right wall tracking, starting inside desired offset, oriented toward wall

Right wall tracking, starting inside desired offset, oriented away from wall

Right wall tracking, starting outside desired offset, oriented toward wall

Right wall tracking, starting outside desired offset, oriented away from wall

Here is the complete code for my wall capture/track test program:

/*
    Name:       FourWD_WallTrackTest.ino
    Created:	6/18/2021 7:20:58 PM
    Author:     FRANKNEWXPS15\Frank
*/

/*
		Name:       FourWD_PulseTurnRateTest.ino
		Created:	5/24/2021 4:49:52 PM
		Author:     FRANKNEWXPS15\Frank
*/

#pragma region INCLUDES
#include <PID_v2.h>
#include <elapsedMillis.h>
#include <PrintEx.h> //allows printf-style printout syntax
#include "MPU6050_6Axis_MotionApps_V6_12.h"  //changed to this version 10/05/19
#include "I2Cdev.h" //02/19/19: this includes SBWire.h
#include "I2C_Anything.h" //needed for sending float data over I2C
#pragma endregion INCLUDES

#pragma region DEFINES
#define MPU6050_I2C_ADDR 0x69
//#define DISTANCES_ONLY //added 11/14/18 to just display distances in infinite loop
#pragma endregion DEFINES

#pragma region PRE_SETUP
StreamEx mySerial = Serial; //added 03/18/18 for printf-style printing
MPU6050 mpu(MPU6050_I2C_ADDR); //06/23/18 chg to AD0 high addr, using INT connected to Mega pin 2 (INT0)
volatile int frontdistval = 0; //10/10/20 chg to volatile 
volatile double frontvar = 0; //08/11/20 now updated in timer1 ISR
const int MAX_FRONT_DISTANCE_CM = 400;
const int FRONT_DIST_AVG_WINDOW_SIZE = 3; //moved here & renamed 04/28/19
const int FRONT_DIST_ARRAY_SIZE = 50; //11/22/20 doubled to acct for 10Hz update rate
uint16_t aFrontDist[FRONT_DIST_ARRAY_SIZE]; //04/18/19 rev to use uint16_t vs byte

//11/03/18 added for new incremental variance calc
double Front_Dist_PrevVar = 0;
double Front_Dist_PrevVMean = 0;
#pragma endregion PRE_SETUP

#pragma region MOTOR_PINS
//09/11/20 Now using two Adafruit DRV8871 drivers for all 4 motors
const int In1_Left = 10;
const int In2_Left = 11;
const int In1_Right = 8;
const int In2_Right = 9;
#pragma endregion Motor Pin Assignments

#pragma region MISC_PIN_ASSIGNMENTS
const int RED_LASER_DIODE_PIN = 7;
const int LIDAR_MODE_PIN = 4; //mvd here 01/10/18
#pragma endregion MISC_PIN_ASSIGNMENTS

#pragma region MOTOR_PARAMETERS
//drive wheel speed parameters
const int MOTOR_SPEED_FULL = 200; //range is 0-255
const int MOTOR_SPEED_MAX = 255; //range is 0-255
const int MOTOR_SPEED_HALF = 127; //range is 0-255
const int MOTOR_SPEED_QTR = 75; //added 09/25/20
const int MOTOR_SPEED_LOW = 50; //added 01/22/15
const int MOTOR_SPEED_OFF = 0; //range is 0-255

//drive wheel direction constants
const boolean FWD_DIR = true;
const boolean REV_DIR = !FWD_DIR;
const bool TURNDIR_CCW = true;
const bool TURNDIR_CW = false;

//Motor direction variables
boolean bLeftMotorDirIsFwd = true;
boolean bRightMotorDirIsFwd = true;
bool bIsForwardDir = true; //default is foward direction

#pragma endregion Motor Parameters

#pragma region HEADING_AND_RATE_BASED_TURN_PARAMETERS
elapsedMillis MsecSinceLastTurnRateUpdate;

const int MAX_PULSE_WIDTH_MSEC = 100;
const int MIN_PULSE_WIDTH_MSEC = 0;

const int MAX_SPIN_MOTOR_SPEED = 250;
const int MIN_SPIN_MOTOR_SPEED = 50;

const int TURN_RATE_UPDATE_INTERVAL_MSEC = 30;

double Prev_HdgDeg = 0;
float tgt_deg;
float timeout_sec;

//05/31/21 latest & greatest PID values
double TurnRate_Kp = 5.0;
double TurnRate_Ki = 1;
double TurnRate_Kd = 0.5;

double TurnRatePIDSetPointDPS, TurnRatePIDOutput;
double TurnRatePIDInput = 15.f;
PID TurnRatePID(&TurnRatePIDInput, &TurnRatePIDOutput, &TurnRatePIDSetPointDPS, TurnRate_Kp, TurnRate_Ki, TurnRate_Kd, DIRECT);

const float HDG_NEAR_MATCH_VAL = 0.8; //slow the turn down here
const float HDG_FULL_MATCH_VAL = 0.99; //stop the turn here //rev 05/17/20
const float HDG_MIN_MATCH_VAL = 0.6; //added 09/08/18: don't start checking slope until turn is well started

#pragma endregion HEADING_AND_RATE_BASED_TURN_PARAMETERS

const double RATIO_TURN_MATCH_THRESHOLD = 0.1;

#pragma region MPU6050_SUPPORT
uint8_t mpuIntStatus;   // holds actual interrupt status byte from MPU. Used in Homer's Overflow routine
uint8_t devStatus;      // return status after each device operation (0 = success, !0 = error)
uint16_t packetSize;    // expected DMP packet size (default is 42 bytes)
uint16_t fifoCount;     // count of all bytes currently in FIFO
uint8_t fifoBuffer[64]; // FIFO storage buffer

						// orientation/motion vars
Quaternion q;           // [w, x, y, z]         quaternion container
VectorInt16 aa;         // [x, y, z]            accel sensor measurements
VectorInt16 aaReal;     // [x, y, z]            gravity-free accel sensor measurements
VectorInt16 aaWorld;    // [x, y, z]            world-frame accel sensor measurements
VectorFloat gravity;    // [x, y, z]            gravity vector
float euler[3];         // [psi, theta, phi]    Euler angle container
float ypr[3];           // [yaw, pitch, roll]   yaw/pitch/roll container and gravity vector
int GetPacketLoopCount = 0;
int OuterGetPacketLoopCount = 0;

//MPU6050 status flags
bool bMPU6050Ready = true;
bool dmpReady = false;  // set true if DMP init was successful
volatile float IMUHdgValDeg = 0; //updated by UpdateIMUHdgValDeg()//11/02/20 now updated in ISR
const uint16_t MAX_GETPACKET_LOOPS = 100; //10/30/19 added for backup loop exit condition in GetCurrentFIFOPacket()
uint8_t GetCurrentFIFOPacket(uint8_t* data, uint8_t length, uint16_t max_loops = MAX_GETPACKET_LOOPS); //prototype here so can define a default param
bool bFirstTime = true;
#define MPU6050_CCW_INCREASES_YAWVAL //added 12/05/19
#pragma endregion MPU6050 Support

#pragma region WALL_FOLLOW_SUPPORT
const int WALL_OFFSET_TRACK_Kp = 100;
const int WALL_OFFSET_TRACK_Ki = 0;
const int WALL_OFFSET_TRACK_Kd = 0;
//const double WALL_OFFSET_TRACK_SETPOINT_LIMIT = 0.3;
//const double WALL_OFFSET_TRACK_SETPOINT_LIMIT = 0.4;
//const double WALL_OFFSET_TRACK_SETPOINT_LIMIT = 0.5;
//const double WALL_OFFSET_TRACK_SETPOINT_LIMIT = 0.15;
const double WALL_OFFSET_TRACK_SETPOINT_LIMIT = 0.25;
double WallTrackSteerVal, WallTrackOutput, WallTrackSetPoint;
const int CHG_CONNECT_LED_PIN = 50; //12/16/20 added for debug
const int WALL_OFFSET_TGTDIST_CM = 30;
double LeftSteeringVal, RightSteeringVal; //added 08/06/20
const int WALL_TRACK_UPDATE_INTERVAL_MSEC = 50;
//const int WALL_TRACK_UPDATE_INTERVAL_MSEC = 30;
#pragma endregion WALL_FOLLOW_SUPPORT

#pragma region VL53L0X LIDAR SUPPORT
//VL53L0X Sensor data values
//11/05/20 revised to make all volatile
volatile int Lidar_RightFront;
volatile int Lidar_RightCenter;
volatile int Lidar_RightRear;
volatile int Lidar_LeftFront;
volatile int Lidar_LeftCenter;
volatile int Lidar_LeftRear;
volatile int Lidar_Rear; //added 10/24/20

bool bVL53L0X_TeensyReady = false; //11/10/20 added to prevent bad data reads during Teensy setup()

enum VL53L0X_REQUEST
{
	VL53L0X_READYCHECK, //added 11/10/20 to prevent bad reads during Teensy setup()
	VL53L0X_CENTERS_ONLY,
	VL53L0X_RIGHT,
	VL53L0X_LEFT,
	VL53L0X_ALL, //added 08/06/20, replaced VL53L0X_BOTH 10/31/20
	VL53L0X_REAR_ONLY //added 10/24/20
};

const int VL53L0X_I2C_SLAVE_ADDRESS = 0x20; ////Teensy 3.5 VL53L0X ToF LIDAR controller

#pragma endregion VL53L0X LIDAR SUPPORT

//************************************************************************************************************************************
//*********************************************************** TIMER ISR **************************************************************
//************************************************************************************************************************************

#pragma region TIMER_ISR
#define TIMER_INT_OUTPUT_PIN 53 //scope monitor pin

bool GetRequestedVL53l0xValues(VL53L0X_REQUEST which);
volatile bool bTimeForNavUpdate = false;
const int TIMER5_INTERVAL_MSEC = 100; //05/15/21 added to eliminate magic number
int GetFrontDistCm();

ISR(TIMER5_COMPA_vect) //timer5 interrupt 5Hz
{
	digitalWrite(TIMER_INT_OUTPUT_PIN, HIGH);//so I can monitor interrupt timing
	delayMicroseconds(30); //leave in - so can see even with NO_STUCK defined

	bTimeForNavUpdate = true;

	//11/2/20 have to re-enable interrupts for I2C comms to work
	interrupts();
	GetRequestedVL53l0xValues(VL53L0X_ALL); //11/2/20 update all distances every 100mSec
	noInterrupts();

	frontdistval = GetFrontDistCm();
	digitalWrite(TIMER_INT_OUTPUT_PIN, LOW);//so I can monitor interrupt timing
}
#pragma endregion TIMER_ISR

void setup()
{
	Serial.begin(115200);

#pragma region MPU6050
	mySerial.printf("\nChecking for MPU6050 IMU at I2C Addr 0x%x\n", MPU6050_I2C_ADDR);
	mpu.initialize();

	// verify connection
	Serial.println(mpu.testConnection() ? F("MPU6050 connection successful") : F("MPU6050 connection failed"));

	float StartSec = 0; //used to time MPU6050 init
	Serial.println(F("Initializing DMP..."));
	devStatus = mpu.dmpInitialize();

	// make sure it worked (returns 0 if successful)
	if (devStatus == 0)
	{
		// turn on the DMP, now that it's ready
		Serial.println(F("Enabling DMP..."));
		mpu.setDMPEnabled(true);

		// set our DMP Ready flag so the main loop() function knows it's okay to use it
		Serial.println(F("DMP ready! Waiting for MPU6050 drift rate to settle..."));
		dmpReady = true;

		// get expected DMP packet size for later comparison
		packetSize = mpu.dmpGetFIFOPacketSize();
		bMPU6050Ready = true;
		StartSec = millis() / 1000.f;
		mySerial.printf("MPU6050 Ready at %2.2f Sec\n", StartSec);
	}
	else
	{
		// ERROR!
		// 1 = initial memory load failed
		// 2 = DMP configuration updates failed
		// (if it's going to break, usually the code will be 1)
		Serial.print(F("DMP Initialization failed (code "));
		Serial.print(devStatus);
		Serial.println(F(")"));

		bMPU6050Ready = false;
	}
#pragma endregion MPU6050

#pragma region PIN_INITIALIZATION
	pinMode(LIDAR_MODE_PIN, INPUT); // Set LIDAR input monitor pin

#pragma endregion PIN_INITIALIZATION


#pragma region TIMER_INTERRUPT
	//09/18/20 can't use Timer1 cuz doing so conflicts with PWM on pins 10-12
	cli();//stop interrupts
	TCCR5A = 0;// set entire TCCR5A register to 0
	TCCR5B = 0;// same for TCCR5B
	TCNT5 = 0;//initialize counter value to 0

	// 06/15/21 rewritten to use defined interval constant rather than magic number
	//10/11/20 chg timer interval to 10Hz vs 5
	//OCR5A = 1562;// = (16*10^6) / (10*1024) - 1 (must be <65536)
	int ocr5a = (16 * 1e6) / ((1000 / TIMER5_INTERVAL_MSEC) * 1024) - 1;
	mySerial.printf("ocr5a = %d\n", ocr5a);
	OCR5A = ocr5a;
	TCCR5B |= (1 << WGM52);// turn on CTC mode
	TCCR5B |= (1 << CS52) | (1 << CS50);// Set CS10 and CS12 bits for 1024 prescaler
	TIMSK5 |= (1 << OCIE5A);// enable timer compare interrupt
	sei();//allow interrupts
	pinMode(TIMER_INT_OUTPUT_PIN, OUTPUT);
#pragma endregion TIMER_INTERRUPT


	//02/08/21 mvd below ISR enable so this section can use ISR-generated VL53L0X distances
#pragma region VL53L0X_TEENSY

	mySerial.printf("Checking for Teensy 3.5 VL53L0X Controller at I2C addr 0x%x\n", VL53L0X_I2C_SLAVE_ADDRESS);
	while (!bVL53L0X_TeensyReady)
	{
		Wire.beginTransmission(VL53L0X_I2C_SLAVE_ADDRESS);
		bVL53L0X_TeensyReady = (Wire.endTransmission() == 0);

		//mySerial.printf("%lu: VL53L0X Teensy Not Avail...\n", millis());
		delay(100);
	}

	mySerial.printf("Teensy available at %lu with bVL53L0X_TeensyReady = %d. Waiting for Teensy setup() to finish\n", millis(), bVL53L0X_TeensyReady);

	WaitForVL53L0XTeensy();

	//mySerial.printf("VL53L0X Teensy Ready at %lu\n\n", millis());
#pragma endregion VL53L0X_TEENSY

	//11/14/18 added this section for distance printout only
	//08/06/20 revised for VL53L0X support
#ifdef DISTANCES_ONLY
	TIMSK5 = 0;
	digitalWrite(RED_LASER_DIODE_PIN, HIGH); //enable the front laser dot
	mySerial.printf("\n------------ DISTANCES ONLY MODE!!! -----------------\n\n");

	int i = 0; //added 09/20/20 for in-line header display
	mySerial.printf("Msec\tLFront\tLCenter\tLRear\tRFront\tRCenter\tRRear\tRear\n");
	while (true)
	{
		//if (bTimeForNavUpdate)
		//{
		//	bTimeForNavUpdate = false;

			//09/20/20 re-display the column headers
			//if (++i % 20 == 0)
			//{
			//	mySerial.printf("\nMsec\tLFront\tLCenter\tLRear\tRFront\tRCenter\tRRear\tFront\tRear\n");
			//}

			//commented out 02/02/21 - now done in ISR
			GetRequestedVL53l0xValues(VL53L0X_ALL);

			mySerial.printf("%lu\t%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d\n",
				millis(), Lidar_LeftFront, Lidar_LeftCenter, Lidar_LeftRear,
				Lidar_RightFront, Lidar_RightCenter, Lidar_RightRear, frontdistval, Lidar_Rear);

		//}

			delay(50);
	}
	TIMSK5 |= (1 << OCIE5A);// enable timer compare interrupt

#endif // DISTANCES_ONLY

#pragma region L/R/FRONT DISTANCE ARRAYS
	//09/20/20 have to do this for parallel finding to go the right way
	Serial.println(F("Initializing Left, Right, Front Distance Arrays..."));
#ifndef NO_PINGS
	//03/30/21 moved FrontDistArray init ahead of left/right dist init to prevent inadvertent 'stuck' detection
	Serial.println(F("Initializing Front Distance Array"));
	InitFrontDistArray(); //08/12/20 code extracted to fcn so can call elsewhere

	//Serial.println(F("Updating Left\tRight Distance Arrays"));
	//for (size_t i = 0; i < LR_DIST_ARRAY_SIZE; i++)
	//{
	//	delay(100); //ensure enough time for ISR to update distances
	//	mySerial.printf("%d\t%d\n", Lidar_LeftCenter, Lidar_RightCenter);
	//	UpdateLRDistanceArrays(Lidar_LeftCenter, Lidar_RightCenter);
	//}

	//Serial.println(F("Updating Rear Distance Arrays"));
	//InitRearDistArray();
	//mySerial.printf("Initial rear prev_mean, prev_var = %2.2f, %2.2f\n",
	//	Rear_Dist_PrevMean, Rear_Dist_PrevVar);
#else
	Serial.println(F("Distance Sensors Disabled"));
#endif // NO_PINGS
#pragma endregion L/R/FRONT DISTANCE ARRAYS

#pragma region WALL_TRACK_TEST
	mySerial.printf("End of test - Stopping!\n");
	//while (true)
	//{
	//	CheckForUserInput();
	//}
	StopBothMotors();
	Serial.println(F("Setting Kp value"));
	const int bufflen = 80;
	char buff[bufflen];
	memset(buff, 0, bufflen);
	float OffsetCm;
	float Kp, Ki, Kd;
	const char s[2] = ",";
	char* token;


	//consume CR/LF chars
	while (Serial.available() > 0)
	{
		int byte = Serial.read();
		mySerial.printf("consumed %d\n", byte);
	}

	while (!Serial.available())
	{
	}

	Serial.readBytes(buff, bufflen);
	mySerial.printf("%s\n", buff);

	/* extract Kp */
	token = strtok(buff, s);
	Kp = atof(token);

	/* extract Ki */
	token = strtok(NULL, s);
	Ki = atof(token);

	/* extract Kd */
	token = strtok(NULL, s);
	Kd = atof(token);

	/* extract Offset in cm */
	token = strtok(NULL, s);
	OffsetCm = atof(token);

	//mySerial.printf("Kp,Ki,Kd,OffsetCm =  %2.2f, %2.2f, %2.2f, %2.2f\n",
	//	Kp, Ki, Kd, OffsetCm);

	//TrackLeftWallOffset(Kp, Ki, Kd, OffsetCm);
	TrackRightWallOffset(Kp, Ki, Kd, OffsetCm);
	//mySerial.printf("Rdist\tCdist\tFdist\tsteer\toffang\n");
	//while (true)
	//{
	//	//double offangdeg = GetSteeringAngle(Lidar_LeftCenter / 10, LeftSteeringVal);
	//	double offangdeg = GetSteeringAngle(LeftSteeringVal); //06/25/21 chg to mm vs cm
	//	mySerial.printf("%d\t%d\t%d\t%2.4f\t%2.2f\n", Lidar_LeftRear, Lidar_LeftCenter, Lidar_LeftFront, LeftSteeringVal, offangdeg);
	//	delay(1000);
	//}
#pragma endregion WALL_TRACK_TEST
}

void loop()
{


}

void CheckForUserInput()
{
	const int bufflen = 80;
	char buff[bufflen];
	memset(buff, 0, bufflen);
	float OffsetCm;
	float Kp, Ki, Kd;
	const char s[2] = ",";
	char* token;

	if (Serial.available() > 0)
	{
		// read the incoming byte:
		int incomingByte = Serial.read();

		// say what you got:
		//Serial.print("I received: ");
		//Serial.println(incomingByte, HEX); //chg to HEX 02/18/20

		//02/18/20 experiment with multiple commands
		switch (incomingByte)
		{
		case 0x43: //ASCII 'C'
		case 0x63: //ASCII 'c'
#pragma region MANUALCONTROL
			//enter infinite loop for direct remote control
			Serial.println(F("ENTERING COMMAND MODE:"));
			Serial.println(F("0 = 180 deg CCW Turn"));
			Serial.println(F("1 = 180 deg CW Turn"));
			Serial.println(F("A = Back to Auto Mode"));
			Serial.println(F("S = Stop"));
			Serial.println(F("F = Forward"));
			Serial.println(F("R = Reverse"));
			Serial.println(F(""));
			Serial.println(F("       Faster"));
			Serial.println(F("\t8"));
			Serial.println(F("Left 4\t5  6 Right"));
			Serial.println(F("\t2"));
			Serial.println(F("       Slower"));

			StopBothMotors();
			int speed = 0;

			bool bAutoMode = false;
			while (!bAutoMode)
			{
				if (Serial.available() > 0)
				{
					// read the incoming byte:
					int incomingByte = Serial.read();

					//mySerial.printf("Got %x\n", incomingByte);

					switch (incomingByte)
					{
					case 0x54: //ASCII 'T'
					case 0x74: //ASCII 't'
						Serial.println(F("Toggle TIMER5 Enable/Disable"));
						if (TIMSK5 == 0)
						{
							Serial.println(F("Enable TIMER5"));
							//TIMSK5 |= OCIE5A;
							TIMSK5 |= (1 << OCIE5A);// enable timer compare interrupt
							mySerial.printf("TIMSK5 = %x\n", TIMSK5);
						}
						else
						{
							Serial.println(F("Disable TIMER5"));
							TIMSK5 = 0;
							mySerial.printf("TIMSK5 = %x\n", TIMSK5);
						}
						break;
					case 0x44: //ASCII 'D'
					case 0x64: //ASCII 'd'
						Serial.println(F("Display left/right distances"));
						if (TIMSK5 == 0)
						{
							Serial.println(F("Enable TIMER5"));
							//TIMSK5 |= OCIE5A;
							TIMSK5 |= (1 << OCIE5A);// enable timer compare interrupt
							mySerial.printf("TIMSK5 = %x\n", TIMSK5);
						}
						mySerial.printf("Msec\tLF\tLC\tLR\tRF\tRC\tRR\n");
						while (true)
						{
							if (bTimeForNavUpdate)
							{
								bTimeForNavUpdate = false;
								mySerial.printf("%lu\t%d\t%d\t%d\t%d\t%d\t%d\n", millis(),
									Lidar_LeftFront, Lidar_LeftCenter, Lidar_LeftRear, Lidar_RightFront, Lidar_RightCenter, Lidar_RightRear);
							}
						}
						break;
					case 0x30: //Dec '0'
						Serial.println(F("CCW 180 deg Turn"));
						//RollingTurn(true, bIsForwardDir, 180);
						//SpinTurn(true, 180, 45);
						SpinTurn(true, 180, 90);
						MoveAhead(speed, speed);
						break;
					case 0x31: //Dec '1'
						Serial.println(F("CW 180 deg Turn"));
						//RollingTurn(false, bIsForwardDir, 180);
						SpinTurn(false, 180, 45);
						//MoveAhead(speed, speed);
						break;
					case 0x34: //Turn left 10 deg
						Serial.println(F("CCW 10 deg Turn"));
						//MoveAhead(speed, speed);
						//RollingTurn(true, bIsForwardDir, 10);
						SpinTurn(true, 10, 30);
						//SpinTurn(true, 30, 30);

						//added 05/03/20
						if (bIsForwardDir)
						{
							MoveAhead(speed, speed);
						}
						else
						{
							MoveReverse(speed, speed);
						}
						break;
					case 0x36: //Turn right 10 deg'
						mySerial.print("CW 10 deg Turn\n");
						MoveAhead(speed, speed);
						//RollingTurn(false, bIsForwardDir, 10);
						SpinTurn(false, 10, 30);
						//SpinTurn(false, 45, 30);

						//added 05/03/20
						if (bIsForwardDir)
						{
							MoveAhead(speed, speed);
						}
						else
						{
							MoveReverse(speed, speed);
						}
						break;
					case 0x38: //Speed up 
						speed += 50;
						speed = (speed >= MOTOR_SPEED_MAX) ? MOTOR_SPEED_MAX : speed;
						mySerial.printf("Speeding up: speed now %d\n", speed);
						if (bIsForwardDir)
						{
							MoveAhead(speed, speed);
						}
						else
						{
							MoveReverse(speed, speed);
						}
						break;
					case 0x32: //Slow down 
						speed -= 50;
						speed = (speed < 0) ? 0 : speed;
						mySerial.printf("Slowing down: speed now %d\n", speed);
						if (bIsForwardDir)
						{
							MoveAhead(speed, speed);
						}
						else
						{
							MoveReverse(speed, speed);
						}
						break;
					case 0x35: //05/07/20 changed to use '5' vs 'S'
						Serial.println(F("Stopping Motors!"));
						StopBothMotors();
						speed = 0;
						break;
					case 0x41: //ASCII 'A'
					case 0x61: //ASCII 'a'
						StopBothMotors();
						Serial.println(F("Re-entering AUTO mode"));
						bAutoMode = true;
						break;
					case 0x52: //ASCII 'R'
					case 0x72: //ASCII 'r'
						Serial.println(F("Setting both motors to reverse"));
						bIsForwardDir = false;
						MoveReverse(speed, speed);
						break;
					case 0x46: //ASCII 'F'
					case 0x66: //ASCII 'f'
						Serial.println(F("Setting both motors to forward"));
						bIsForwardDir = true;
						MoveAhead(speed, speed);
#pragma endregion MANUALCONTROL
						break;

#pragma region	WALL OFFSET TRACKING CASES
						//left side wall tracking
					case 0x4C: //ASCII 'L'
					case 0x6C: //ASCII 'l'
						StopBothMotors();
						Serial.println(F("Setting Kp value"));

						//consume CR/LF chars
						while (Serial.available() > 0)
						{
							int byte = Serial.read();
							mySerial.printf("consumed %d\n", byte);
						}

						while (!Serial.available())
						{
						}

						Serial.readBytes(buff, bufflen);
						mySerial.printf("%s\n", buff);

						/* extract Kp */
						token = strtok(buff, s);
						Kp = atof(token);

						/* extract Ki */
						token = strtok(NULL, s);
						Ki = atof(token);

						/* extract Kd */
						token = strtok(NULL, s);
						Kd = atof(token);

						/* extract Offset in cm */
						token = strtok(NULL, s);
						OffsetCm = atof(token);

						mySerial.printf("Kp,Ki,Kd,OffsetCm =  %2.2f, %2.2f, %2.2f, %2.2f\n",
							Kp, Ki, Kd, OffsetCm);

						TrackLeftWallOffset(Kp, Ki, Kd, OffsetCm);
						break;
					case 0x4D: //ASCII 'M'
					case 0x6D: //ASCII 'm'
						StopBothMotors();
						Serial.println(F("Setting Kp value"));

						//consume CR/LF chars
						while (Serial.available() > 0)
						{
							int byte = Serial.read();
							mySerial.printf("consumed %d\n", byte);
						}

						while (!Serial.available())
						{
						}

						Serial.readBytes(buff, bufflen);
						mySerial.printf("%s\n", buff);

						/* extract Kp */
						token = strtok(buff, s);
						Kp = atof(token);

						/* extract Ki */
						token = strtok(NULL, s);
						Ki = atof(token);

						/* extract Kd */
						token = strtok(NULL, s);
						Kd = atof(token);

						/* extract Offset in cm */
						token = strtok(NULL, s);
						OffsetCm = atof(token);

						mySerial.printf("Kp,Ki,Kd,OffsetCm =  %2.2f, %2.2f, %2.2f, %2.2f\n",
							Kp, Ki, Kd, OffsetCm);

						TrackRightWallOffset(Kp, Ki, Kd, OffsetCm);
						break;
#pragma endregion	WALL OFFSET TRACKING CASES
						Default:
						Serial.println(F("In Default Case: Stopping Motors!"));
						MoveAhead(0, 0);
						while (true)
						{

						}
					}
				}
			}
		}
	}
}

void TrackLeftWallOffset(double kp, double ki, double kd, double offsetCm)
{
	//Notes:
	//	06/21/21 modified to do a turn, then straight, then track 0 steer val

	elapsedMillis sinceLastComputeTime = 0;
	double lastError = 0;
	double lastInput = 0;
	double lastIval = 0;
	double lastDerror = 0;
	bool bFirstTime = true;
	double spinRateDPS = 45;

	GetRequestedVL53l0xValues(VL53L0X_LEFT); //update LeftSteeringVal

	mySerial.printf("Kp/Ki/Kd = %2.2f\t%2.2f\t%2.2f\n", kp, ki, kd);

	//06/21/21 modified to do a turn, then straight, then track 0 steer val
	double cutAngleDeg = WALL_OFFSET_TGTDIST_CM - (int)(Lidar_LeftCenter / 10.f);//positive inside, negative outside desired offset

	//07/05/21 implement 15deg min cut angle
	if (cutAngleDeg < 0 && abs(cutAngleDeg) < 15)
	{
		cutAngleDeg = -15;
	}
	else if (cutAngleDeg > 0 && cutAngleDeg < 15 )
	{
		cutAngleDeg = 15;
	}

	double SteerAngleDeg = GetSteeringAngle(LeftSteeringVal);

	mySerial.printf("R/C/F dists = %d\t%d\t%d Steerval = %2.3f, SteerAngle = %2.2f, CutAngle = %2.2f\n", 
		Lidar_LeftRear, Lidar_LeftCenter, Lidar_LeftFront, LeftSteeringVal, SteerAngleDeg, cutAngleDeg);

	double adjCutAngleDeg = 0;
	uint16_t fudgeFactorMM = 0; //07/05/21 added so can change for inside vs outside starting condx
	if (cutAngleDeg > 0) //robot inside desired offset distance
	{
		if (SteerAngleDeg > cutAngleDeg)  // --> SteerAngleDeg also > 0
		{
			mySerial.printf("if (SteerAngleDeg > cutAngleDeg)\n");
			SpinTurn(true, SteerAngleDeg - cutAngleDeg, spinRateDPS); //
		}
		else if (SteerAngleDeg < cutAngleDeg)// --> SteerAngleDeg could be < 0
		{
			if (SteerAngleDeg <= 0 ) //cutAngleDeg > 0, SteerAngleDeg <= 0
			{
				mySerial.printf("if (SteerAngleDeg <= 0)\n");
				SpinTurn(false,cutAngleDeg - SteerAngleDeg, spinRateDPS); //null out SteerAngleDeg & then turn addnl cutAngleDeg
			}
			else //SteerAngleDeg < cutAngleDeg but still > 0
			{
				mySerial.printf("else\n");
				SpinTurn(false,cutAngleDeg - SteerAngleDeg, spinRateDPS); //turn diff between SteerAngleDeg & cutAngleDeg
			}
		}

		fudgeFactorMM = -100; //07/05/21 don't need fudge factor for inside start condx
	}
	else // cutAngleDeg < 0 --> robot outside desired offset distance
	{
		if (SteerAngleDeg > cutAngleDeg)  // --> SteerAngleDeg may also be > 0
		{
			mySerial.printf("if (SteerAngleDeg > cutAngleDeg)\n");
			SpinTurn(true, SteerAngleDeg - cutAngleDeg, spinRateDPS); //
		}
		else if (SteerAngleDeg < cutAngleDeg)// --> SteerAngleDeg must also be < 0
		{
			if (SteerAngleDeg <= 0) //cutAngleDeg > 0, SteerAngleDeg <= 0
			{
				mySerial.printf("if (SteerAngleDeg <= 0)\n");
				SpinTurn(false, cutAngleDeg - SteerAngleDeg, spinRateDPS); //null out SteerAngleDeg & then turn addnl cutAngleDeg
			}
			else //SteerAngleDeg < cutAngleDeg but still > 0
			{
				mySerial.printf("else\n");
				SpinTurn(false, cutAngleDeg - SteerAngleDeg, spinRateDPS); //turn diff between SteerAngleDeg & cutAngleDeg
			}
		}

		fudgeFactorMM = 100; //07/05/21 need fudge factor for outside start condx
	}

	delay(1000);

	//adjust so offset capture occurs at correct perpendicular offset
	//double adjfactor = cos(PI * avgAppAngle / 180.f);
	double adjfactor = cos(PI * cutAngleDeg / 180.f);
	int adjOffsetMM = (int)(10 * (double)WALL_OFFSET_TGTDIST_CM / adjfactor);
	//adjOffsetMM += 100; //fudge factor for distance measurements lagging behind robot's travel. 
	adjOffsetMM += fudgeFactorMM; //fudge factor for distance measurements lagging behind robot's travel. 
	//mySerial.printf("at approach start: steerval = %2.3f, adj cut angle = %2.2f, adjfactor = %2.3f, tgt dist = %d\n", avgSteerVal, avgAppAngle, adjfactor, adjOffsetMM);
	mySerial.printf("at approach start: cut angle = %2.3f, adjfactor = %2.3f, tgt dist = %d\n", cutAngleDeg, adjfactor, adjOffsetMM);

	//long int prev_res = Lidar_LeftFront - 10 * WALL_OFFSET_TGTDIST_CM; //neg for inside going out, pos for outside going in
	long int prev_res = Lidar_LeftFront - adjOffsetMM; //neg for inside going out, pos for outside going in
	long int res = prev_res;
	mySerial.printf("At start - prev_res = %ld\n", prev_res);

	mySerial.printf("Msec\tLFront\tLCtr\tLRear\tFront\tRear\tRes\tP_res\n");

	//TIMSK5 = 0; //turn off TIMER5 interrupts
	while (prev_res * res > 0) //sign change makes this < 0
	{
		
		prev_res = res;

		MoveAhead(MOTOR_SPEED_QTR, MOTOR_SPEED_QTR);
		while (!bTimeForNavUpdate)
		{

		}
		bTimeForNavUpdate = false;
		frontdistval = GetFrontDistCm();
		res = Lidar_LeftFront - adjOffsetMM; //06/29/21 now adj for slant dist vs perp dist
		mySerial.printf("%lu\t%d\t%d\t%d\t%d\t%d\t%ld\t%ld\n",
			millis(),
			Lidar_LeftFront, Lidar_LeftCenter, Lidar_LeftRear, frontdistval, Lidar_Rear, res, prev_res);
		CheckForUserInput();
	}

	//now turn back the same (unadjusted) amount
	mySerial.printf("At end - prev_res*res = %ld\n", prev_res*res);
	mySerial.printf("correct back to parallel\n");
	SpinTurn(!(cutAngleDeg < 0), abs(cutAngleDeg), spinRateDPS); //have to use abs() here, as cutAngleDeg can be neg

	//sinceLastComputeTime = 0;
		WallTrackSetPoint = 0; //moved here 6/22/21
		//TIMSK5 |= (1 << OCIE5A);// enable timer compare interrupt

	mySerial.printf("Msec\tFdir\tCdir\tRdir\tSteer\tSet\terror\tIval\tKp*err\tKi*Ival\tKd*Din\tOutput\tLspd\tRspd\n");

	while (true)
	{
		CheckForUserInput(); //this is a bit recursive, but should still work (I hope)

		//now using TIMER5 100 mSec interrupt for timing
		if (bTimeForNavUpdate)
		{
			//sinceLastComputeTime -= WALL_TRACK_UPDATE_INTERVAL_MSEC;
			bTimeForNavUpdate = false;

			//GetRequestedVL53l0xValues(VL53L0X_LEFT); //now done in TIMER5 ISR

			//have to weight value by both angle and wall offset
			WallTrackSteerVal = LeftSteeringVal + (Lidar_LeftCenter - 10 * WALL_OFFSET_TGTDIST_CM) / 1000.f;

			//update motor speeds, skipping bad values
			if (!isnan(WallTrackSteerVal))
			{
				//10/12/20 now this executes every time, with interval controlled by timer ISR
				PIDCalcs(WallTrackSteerVal, WallTrackSetPoint, TIMER5_INTERVAL_MSEC, lastError, lastInput, lastIval, lastDerror,
					kp, ki, kd, WallTrackOutput);

				int speed = 0;

				int leftspeednum = MOTOR_SPEED_QTR + WallTrackOutput;
				int rightspeednum = MOTOR_SPEED_QTR - WallTrackOutput;

				rightspeednum = (rightspeednum <= MOTOR_SPEED_FULL) ? rightspeednum : MOTOR_SPEED_FULL;
				rightspeednum = (rightspeednum > 0) ? rightspeednum : 0;
				leftspeednum = (leftspeednum <= MOTOR_SPEED_FULL) ? leftspeednum : MOTOR_SPEED_FULL;
				leftspeednum = (leftspeednum > 0) ? leftspeednum : 0;

				MoveAhead(leftspeednum, rightspeednum);

				mySerial.printf("%lu \t%d\t%d\t%d \t%2.2f\t%2.2f\t%2.2f\t%2.2f \t%2.2f\t%2.2f\t%2.2f \t%2.2f\t%d\t%d\n",
					millis(),
					Lidar_LeftFront, Lidar_LeftCenter, Lidar_LeftRear,
					WallTrackSteerVal, WallTrackSetPoint, lastError, lastIval,
					kp * lastError, ki * lastIval, kd * lastDerror,
					WallTrackOutput, leftspeednum, rightspeednum);
			}
		}
	}
}

void TrackRightWallOffset(double kp, double ki, double kd, double offsetCm)
{
	//Notes:
	//	06/21/21 modified to do a turn, then straight, then track 0 steer val

	elapsedMillis sinceLastComputeTime = 0;
	double lastError = 0;
	double lastInput = 0;
	double lastIval = 0;
	double lastDerror = 0;
	bool bFirstTime = true;
	double spinRateDPS = 45;

	GetRequestedVL53l0xValues(VL53L0X_RIGHT); //update RightSteeringVal = (Front - Rear)/100

	mySerial.printf("Kp/Ki/Kd = %2.2f\t%2.2f\t%2.2f\n", kp, ki, kd);

	//06/21/21 modified to do a turn, then straight, then track 0 steer val
	double cutAngleDeg = WALL_OFFSET_TGTDIST_CM - (int)(Lidar_RightCenter / 10.f);//positive inside, negative outside desired offset

	//07/05/21 implement 15deg min cut angle
	if (cutAngleDeg < 0 && abs(cutAngleDeg) < 15)
	{
		cutAngleDeg = -15;
	}
	else if (cutAngleDeg > 0 && cutAngleDeg < 15)
	{
		cutAngleDeg = 15;
	}

	double SteerAngleDeg = GetSteeringAngle(RightSteeringVal);

	mySerial.printf("R/C/F dists = %d\t%d\t%d Steerval = %2.3f, SteerAngle = %2.2f, CutAngle = %2.2f\n",
		Lidar_RightRear, Lidar_RightCenter, Lidar_RightFront, RightSteeringVal, SteerAngleDeg, cutAngleDeg);

	double adjCutAngleDeg = 0;
	uint16_t fudgeFactorMM = 0; //07/05/21 added so can change for inside vs outside starting condx
	if (cutAngleDeg > 0) //robot inside desired offset distance
	{
		if (SteerAngleDeg > cutAngleDeg)  // --> SteerAngleDeg also > 0 (pointing away from wall)
		{
			mySerial.printf("if (SteerAngleDeg > cutAngleDeg)\n");
			SpinTurn(false, SteerAngleDeg - cutAngleDeg, spinRateDPS); //
		}
		else if (SteerAngleDeg < cutAngleDeg)// --> SteerAngleDeg could be < 0
		{
			if (SteerAngleDeg <= 0) //cutAngleDeg > 0, SteerAngleDeg <= 0
			{
				mySerial.printf("if (SteerAngleDeg <= 0)\n");
				//SpinTurn(false, cutAngleDeg - SteerAngleDeg, spinRateDPS); //null out SteerAngleDeg & then turn addnl cutAngleDeg
				SpinTurn(true, cutAngleDeg - SteerAngleDeg, spinRateDPS); //null out SteerAngleDeg & then turn addnl cutAngleDeg
			}
			else //SteerAngleDeg < cutAngleDeg but still > 0
			{
				mySerial.printf("else\n");
				//SpinTurn(false, cutAngleDeg - SteerAngleDeg, spinRateDPS); //turn diff between SteerAngleDeg & cutAngleDeg
				SpinTurn(true, cutAngleDeg - SteerAngleDeg, spinRateDPS); //turn diff between SteerAngleDeg & cutAngleDeg
			}
		}

		fudgeFactorMM = -100; //07/05/21 don't need fudge factor for inside start condx
	}
	else // cutAngleDeg < 0 --> robot outside desired offset distance
	{
		if (SteerAngleDeg > cutAngleDeg)  // --> SteerAngleDeg may also be > 0
		{
			mySerial.printf("if (SteerAngleDeg > cutAngleDeg)\n");
			SpinTurn(false, SteerAngleDeg - cutAngleDeg, spinRateDPS); //
		}
		else if (SteerAngleDeg < cutAngleDeg)// --> SteerAngleDeg must also be < 0
		{
			if (SteerAngleDeg <= 0) //cutAngleDeg > 0, SteerAngleDeg <= 0
			{
				mySerial.printf("if (SteerAngleDeg <= 0)\n");
				//SpinTurn(false, cutAngleDeg - SteerAngleDeg, spinRateDPS); //null out SteerAngleDeg & then turn addnl cutAngleDeg
				SpinTurn(true, cutAngleDeg - SteerAngleDeg, spinRateDPS); //null out SteerAngleDeg & then turn addnl cutAngleDeg
			}
			else //SteerAngleDeg < cutAngleDeg but still > 0
			{
				mySerial.printf("else\n");
				//SpinTurn(false, cutAngleDeg - SteerAngleDeg, spinRateDPS); //turn diff between SteerAngleDeg & cutAngleDeg
				SpinTurn(true, cutAngleDeg - SteerAngleDeg, spinRateDPS); //turn diff between SteerAngleDeg & cutAngleDeg
			}
		}

		fudgeFactorMM = 100; //07/05/21 need fudge factor for outside start condx
	}
	//DEBUG!!
		//mySerial.printf("Msec\tFront\tCtr\ttRear\tSteer\tAngle\n");
		//double sumOfSteerVals = 0;
		//for (size_t i = 0; i < 10; i++)
		//{
		//	while (!bTimeForNavUpdate)
		//	{

		//	}
		//	bTimeForNavUpdate = false;
		//	//GetRequestedVL53l0xValues(VL53L0X_LEFT); //refresh steering value
		//	mySerial.printf("%lu\t%d\t%d\t%d\t%2.3f\t%2.2f\n",millis(), 
		//		Lidar_RightFront, Lidar_RightCenter, Lidar_RightRear, RightSteeringVal, GetSteeringAngle(RightSteeringVal));
		//	sumOfSteerVals += RightSteeringVal;
		//	//delay(100);
		//}

		//double avgSteerVal = sumOfSteerVals / 10.f;
		//double avgAppAngle = GetSteeringAngle(avgSteerVal);
		//mySerial.printf("avg steerval = %2.3f, avg angle = %2.3f\n", avgSteerVal, avgAppAngle);
	//DEBUG!!

	delay(1000);

	//adjust so offset capture occurs at correct perpendicular offset
	//double adjfactor = cos(PI * avgAppAngle / 180.f);
	double adjfactor = cos(PI * cutAngleDeg / 180.f);
	int adjOffsetMM = (int)(10 * (double)WALL_OFFSET_TGTDIST_CM / adjfactor);
	//adjOffsetMM += 100; //fudge factor for distance measurements lagging behind robot's travel. 
	adjOffsetMM += fudgeFactorMM; //fudge factor for distance measurements lagging behind robot's travel. 
	//mySerial.printf("at approach start: steerval = %2.3f, adj cut angle = %2.2f, adjfactor = %2.3f, tgt dist = %d\n", avgSteerVal, avgAppAngle, adjfactor, adjOffsetMM);
	mySerial.printf("at approach start: cut angle = %2.3f, adjfactor = %2.3f, tgt dist = %d\n", cutAngleDeg, adjfactor, adjOffsetMM);

	//long int prev_res = Lidar_RightFront - 10 * WALL_OFFSET_TGTDIST_CM; //neg for inside going out, pos for outside going in
	long int prev_res = Lidar_RightFront - adjOffsetMM; //neg for inside going out, pos for outside going in
	long int res = prev_res;
	mySerial.printf("At start - prev_res = %ld\n", prev_res);

	mySerial.printf("Msec\tLFront\tLCtr\tLRear\tFront\tRear\tRes\tP_res\n");

	//TIMSK5 = 0; //turn off TIMER5 interrupts
	while (prev_res * res > 0) //sign change makes this < 0
	{

		prev_res = res;

		MoveAhead(MOTOR_SPEED_QTR, MOTOR_SPEED_QTR);
		while (!bTimeForNavUpdate)
		{

		}
		bTimeForNavUpdate = false;
		frontdistval = GetFrontDistCm();
		res = Lidar_RightFront - adjOffsetMM; //06/29/21 now adj for slant dist vs perp dist
		mySerial.printf("%lu\t%d\t%d\t%d\t%d\t%d\t%ld\t%ld\n",
			millis(),
			Lidar_RightFront, Lidar_RightCenter, Lidar_RightRear, frontdistval, Lidar_Rear, res, prev_res);
		CheckForUserInput();
	}

	//now turn back the same (unadjusted) amount
	mySerial.printf("At end - prev_res*res = %ld\n", prev_res * res);
	mySerial.printf("correct back to parallel\n");
	//SpinTurn(!(cutAngleDeg < 0), abs(cutAngleDeg), spinRateDPS); //have to use abs() here, as cutAngleDeg can be neg
	SpinTurn((cutAngleDeg < 0), abs(cutAngleDeg), spinRateDPS); //have to use abs() here, as cutAngleDeg can be neg

	//sinceLastComputeTime = 0;
	WallTrackSetPoint = 0; //moved here 6/22/21
	//TIMSK5 |= (1 << OCIE5A);// enable timer compare interrupt

	mySerial.printf("Msec\tFdir\tCdir\tRdir\tSteer\tSet\terror\tIval\tKp*err\tKi*Ival\tKd*Din\tOutput\tLspd\tRspd\n");

	while (true)
	{
		CheckForUserInput(); //this is a bit recursive, but should still work (I hope)

		//now using TIMER5 100 mSec interrupt for timing
		if (bTimeForNavUpdate)
		{
			//sinceLastComputeTime -= WALL_TRACK_UPDATE_INTERVAL_MSEC;
			bTimeForNavUpdate = false;

			//GetRequestedVL53l0xValues(VL53L0X_LEFT); //now done in TIMER5 ISR

			//have to weight value by both angle and wall offset
			WallTrackSteerVal = RightSteeringVal + (Lidar_RightCenter - 10 * WALL_OFFSET_TGTDIST_CM) / 1000.f;

			//update motor speeds, skipping bad values
			if (!isnan(WallTrackSteerVal))
			{
				//10/12/20 now this executes every time, with interval controlled by timer ISR
				//PIDCalcs(WallTrackSteerVal, WallTrackSetPoint, TIMER5_INTERVAL_MSEC, lastError, lastInput, lastIval, lastDerror,
				//	kp, ki, kd, WallTrackOutput);
				PIDCalcs(WallTrackSteerVal, WallTrackSetPoint, TIMER5_INTERVAL_MSEC, lastError, lastInput, lastIval, lastDerror,
					kp, ki, kd, WallTrackOutput);

				int speed = 0;

				//07/05/21 reverse signs for right side tracking 
				//int leftspeednum = MOTOR_SPEED_QTR + WallTrackOutput;
				//int rightspeednum = MOTOR_SPEED_QTR - WallTrackOutput;
				int leftspeednum = MOTOR_SPEED_QTR - WallTrackOutput;
				int rightspeednum = MOTOR_SPEED_QTR + WallTrackOutput;

				rightspeednum = (rightspeednum <= MOTOR_SPEED_FULL) ? rightspeednum : MOTOR_SPEED_FULL;
				rightspeednum = (rightspeednum > 0) ? rightspeednum : 0;
				leftspeednum = (leftspeednum <= MOTOR_SPEED_FULL) ? leftspeednum : MOTOR_SPEED_FULL;
				leftspeednum = (leftspeednum > 0) ? leftspeednum : 0;

				MoveAhead(leftspeednum, rightspeednum);

				//mySerial.printf("%lu \t%d\t%d\t%d \t%2.2f\t%2.2f\t%2.2f\t%2.2f \t%2.2f\t%2.2f\t%2.2f \t%2.2f\t%d\t%d\n",
				//	millis(),
				//	Lidar_RightFront, Lidar_RightCenter, Lidar_RightRear,
				//	WallTrackSteerVal, WallTrackSetPoint, lastError, lastIval,
				//	kp * lastError, ki * lastIval, kd * lastDerror,
				//	WallTrackOutput, leftspeednum, rightspeednum);
				mySerial.printf("%lu \t%d\t%d\t%d \t%2.2f\t%2.2f\t%2.2f\t%2.2f \t%2.2f\t%2.2f\t%2.2f \t%2.2f\t%d\t%d\n",
					millis(),
					Lidar_RightFront, Lidar_RightCenter, Lidar_RightRear,
					-WallTrackSteerVal, WallTrackSetPoint, lastError, lastIval,
					kp * lastError, ki * lastIval, kd * lastDerror,
					WallTrackOutput, leftspeednum, rightspeednum);
			}
		}
	}
}

#pragma region MOTOR SUPPORT
//09/08/20 modified for DRV8871 motor driver
void MoveReverse(int leftspeednum, int rightspeednum)
{
	//Purpose:  Move in reverse direction continuously - companion to MoveAhead()
	//ProvEnA_Pinnce: G. Frank Paynter 09/08/18
	//Inputs:  
	//    leftspeednum = integer denoting speed (0=stop, 255 = full speed)
	//    rightspeednum = integer denoting speed (0=stop, 255 = full speed)
	//Outputs: both drive Motors energized with the specified speed
	//Plan:
	//    Step 1: Set reverse direction for both wheels
	//    Step 2: Run both Motors at specified speeds
	//Notes:
	//	01/22/20 now using Adafruit DRV8871 drivers

	//Step 1: Set reverse direction and speed for both wheels
	SetLeftMotorDirAndSpeed(REV_DIR, leftspeednum);
	SetRightMotorDirAndSpeed(REV_DIR, rightspeednum);
}

//09/08/20 modified for DRV8871 motor driver
void MoveAhead(int leftspeednum, int rightspeednum)
{
	//Purpose:  Move ahead continuously
	//ProvEnA_Pinnce: G. Frank Paynter and Danny Frank 01/24/2014
	//Inputs:  
	//    leftspeednum = integer denoting speed (0=stop, 255 = full speed)
	//    rightspeednum = integer denoting speed (0=stop, 255 = full speed)
	//Outputs: both drive Motors energized with the specified speed
	//Plan:
	//    Step 1: Set forward direction for both wheels
	//    Step 2: Run both Motors at specified speeds
	//Notes:
	//	01/22/20 now using Adafruit DRV8871 drivers

	//mySerial.printf("InMoveAhead(%d,%d)\n", leftspeednum, rightspeednum);

	//Step 1: Set forward direction and speed for both wheels
	SetLeftMotorDirAndSpeed(true, leftspeednum);
	SetRightMotorDirAndSpeed(true, rightspeednum);
}

//09/08/10 modified for DRV8871 motor driver
void StopLeftMotors()
{
	analogWrite(In1_Left, MOTOR_SPEED_OFF);
	analogWrite(In2_Left, MOTOR_SPEED_OFF);
}

void StopRightMotors()
{
	analogWrite(In1_Right, MOTOR_SPEED_OFF);
	analogWrite(In2_Right, MOTOR_SPEED_OFF);
}

//09/08/20 added bool bisFwd param for DRV8871 motor driver
void RunBothMotors(bool bisFwd, int leftspeednum, int rightspeednum)
{
	//Purpose: Run both Motors at left/rightspeednum speeds
	//Inputs:
	//    speednum = speed value (0 = OFF, 255 = full speed)
	//Outputs: Both Motors run for timesec seconds at speednum speed
	//Plan:
	//    Step 1: Apply drive to both wheels
	//Notes:
	//    01/14/15 - added left/right speed offset for straightness compensation
	//    01/22/15 - added code to restrict fast/slow values
	//    01/24/15 - revised for continuous run - no timing
	//  01/26/15 - speednum modifications moved to UpdateWallFollowmyMotorspeeds()
	//	12/07/15 - chg args from &int to int
	//Step 1: Apply drive to both wheels

//DEBUG!!
	//mySerial.printf("In RunBothMotors(%s, %d,%d)\n", bisFwd? "FWD":"REV", leftspeednum, rightspeednum);
//DEBUG!!

	SetLeftMotorDirAndSpeed(bisFwd, leftspeednum);
	SetRightMotorDirAndSpeed(bisFwd, rightspeednum);
}

void RunBothMotorsBidirectional(int leftspeed, int rightspeed)
{
	//Purpose:  Accommodate the need for independent bidirectional wheel motion
	//Inputs:
	//	leftspeed - integer denoting left wheel speed.  Positive value is fwd, negative is rev
	//	rightspeed - integer denoting right wheel speed.  Positive value is fwd, negative is rev
	//Outputs:
	//	left/right wheel motors direction and speed set as appropriate
	//Plan:
	//	Step1: Set left wheel direction and speed
	//	Step2: Set right wheel direction and speed

//Step1: Set left wheel direction and speed

	//DEBUG!!
	//mySerial.printf("In RunBothMotorsBidirectional(%d, %d)\n", leftspeed, rightspeed);
	if (leftspeed < 0)
	{
		SetLeftMotorDirAndSpeed(false, -leftspeed); //neg value ==> reverse
	}
	else
	{
		SetLeftMotorDirAndSpeed(true, leftspeed); //pos or zero value ==> fwd
	}

	//Step2: Set right wheel direction and speed
	if (rightspeed < 0)
	{
		SetRightMotorDirAndSpeed(false, -rightspeed); //neg value ==> reverse
	}
	else
	{
		SetRightMotorDirAndSpeed(true, rightspeed); //pos or zero value ==> fwd
	}
}

//09/08/20 added bool bisFwd param for DRV8871 motor driver
void RunBothMotorsMsec(bool bisFwd, int timeMsec, int leftspeednum, int rightspeednum)
{
	//Purpose: Run both Motors for timesec seconds at speednum speed
	//Inputs:
	//    timesec = time in seconds to run the Motors
	//    speednum = speed value (0 = OFF, 255 = full speed)
	//Outputs: Both Motors run for timesec seconds at speednum speed
	//Plan:
	//    Step 1: Apply drive to both wheels
	//    Step 2: Delay timsec seconds
	//    Step 3: Remove drive from both wheels.
	//Notes:
	//    01/14/15 - added left/right speed offset for straightness compensation
	//    01/22/15 - added code to restrict fast/slow values
	//	11/25/15 - rev to use motor driver class object
	//	09/08/20 added bool bisFwd param for DRV8871 motor driver

	RunBothMotors(bisFwd, leftspeednum, rightspeednum);

	//Step 2: Delay timsec seconds
	delay(timeMsec);

	//Step3: Stop motors added 04/12/21
	StopBothMotors();
}

//11/25/15 added for symmetry ;-).
void StopBothMotors()
{
	StopLeftMotors();
	StopRightMotors();
}

void SetLeftMotorDirAndSpeed(bool bIsFwd, int speed)
{
	//mySerial.printf("SetLeftMotorDirAndSpeed(%d,%d)\n", bIsFwd, speed);

#ifndef NO_MOTORS
	if (bIsFwd)
	{
		digitalWrite(In1_Left, LOW);
		analogWrite(In2_Left, speed);
		//mySerial.printf("In TRUE block of SetLeftMotorDirAndSpeed(%s, %d)\n",
		//	(bIsFwd == true) ? "true" : "false", speed);
	}
	else
	{
		//mySerial.printf("In FALSE block of SetLeftMotorDirAndSpeed(%s, %d)\n",
		//	(bIsFwd == true) ? "true" : "false", speed);
		digitalWrite(In2_Left, LOW);
		analogWrite(In1_Left, speed);
	}
#endif // !NO_MOTORS
}

void SetRightMotorDirAndSpeed(bool bIsFwd, int speed)
{
	//mySerial.printf("In SetRightMotorDirAndSpeed(%s, %d)\n",
	//	(bIsFwd == true) ? "true" : "false", speed);

#ifndef NO_MOTORS

	if (bIsFwd)
	{
		//mySerial.printf("In TRUE block of SetRighttMotorDirAndSpeed(%s, %d)\n",
		//	(bIsFwd == true) ? "true" : "false", speed);
		digitalWrite(In1_Right, LOW);
		analogWrite(In2_Right, speed);
	}
	else
	{
		//mySerial.printf("In FALSE block of SetRightMotorDirAndSpeed(%s, %d)\n",
		//	(bIsFwd == true) ? "true" : "false", speed);
		digitalWrite(In2_Right, LOW);
		analogWrite(In1_Right, speed);
	}

#endif // !NO_MOTORS
}

#pragma endregion Motor Support Functions

#pragma region MPU5060 Support
float UpdateIMUHdgValDeg()
{
	//Purpose: Get latest yaw (heading) value from IMU
	//Inputs: None.  This function should only be called after mpu.dmpPacketAvailable() returns TRUE
	//Outputs: 
	//	returns true if successful, otherwise false
	//	IMUHdgValDeg updated on success
	//Plan:
	//Step1: check for overflow and reset the FIFO if it occurs. In this case, wait for new packet
	//Step2: read all available packets to get to latest data
	//Step3: update IMUHdgValDeg with latest value
	//Notes:
	//	10/08/19 changed return type to boolean
	//	10/08/19 no longer need mpuIntStatus
	//	10/21/19 completely rewritten to use Homer's algorithm
	//	05/05/20 changed return type to float vs bool.

	bool retval = false;

	int flag = GetCurrentFIFOPacket(fifoBuffer, packetSize, MAX_GETPACKET_LOOPS); //get the latest mpu packet

	if (flag != 0) //0 = error exit, 1 = normal exit, 2 = recovered from an overflow
	{
		// display Euler angles in degrees
		mpu.dmpGetQuaternion(&q, fifoBuffer);
		mpu.dmpGetGravity(&gravity, &q);
		mpu.dmpGetYawPitchRoll(ypr, &q, &gravity);

		//compute the yaw value
		IMUHdgValDeg = ypr[0] * 180 / M_PI;
		retval = true;
	}

	//return retval;
	return IMUHdgValDeg;//05/05/20 now returns updated value for use convenience
}

uint8_t GetCurrentFIFOPacket(uint8_t* data, uint8_t length, uint16_t max_loops)
{
	mpu.resetFIFO();
	delay(1);
	//int countloop = 0;

	fifoCount = mpu.getFIFOCount();
	GetPacketLoopCount = 0;

	//mySerial.printf("In GetCurrentFIFOPacket: before loop fifoC = %d\t", fifoCount);
	while (fifoCount < packetSize && GetPacketLoopCount < max_loops)
	{
		GetPacketLoopCount++;
		fifoCount = mpu.getFIFOCount();
		delay(2);
	}

	//mySerial.printf("In GetCurrentFIFOPacket: after loop fifoC = %d, loop count = %d\n", fifoCount, GetPacketLoopCount);

	if (GetPacketLoopCount >= max_loops)
	{
		return 0;
	}

	//if we get to here, there should be exactly one packet in the FIFO
	mpu.getFIFOBytes(data, packetSize);
	return 1;
}
#pragma endregion MPU5060 Support

#pragma region HDG_BASED_TURN_SUPPORT

float GetHdgMatchVal(float tgt_deg, float cur_deg)
{
	//Purpose:  Compute the match ratio between two compass headings
	//Inputs:
	//	tgt_deg = float representing target heading in +/-180 range
	//	IMUHdgValDeg = float representing sensor yaw value in +/-180 deg range
	//Outputs:
	//	returns result of 1 - abs(Tgt_deg - Hdg_deg)/180, all angles in 0-360 deg range
	//Plan:
	//	Step1: convert both inputs to 0-360 deg range
	//	Step2: compute match ratio
	//Notes:
	//	formula from https://gis.stackexchange.com/questions/129954/comparing-compass-bearings

//Step1: convert both inputs to 0-360 deg range
	float tgthdg = (tgt_deg < 0) ? tgt_deg + 360 : tgt_deg;
	float curhdg = (cur_deg < 0) ? cur_deg + 360 : cur_deg;

	//Step2: compute match ratio
	float match_ratio = 1 - abs(tgthdg - curhdg) / 180;

	//DEBUG!!
		//mySerial.printf("tgt\tcur\tmatch = %4.2f\t%4.2f\t%1.3f\n", tgthdg, curhdg, match_ratio);
	//DEBUG!!
	return abs(match_ratio);
}

bool SpinTurn(bool b_ccw, float numDeg, float degPersec) //04/25/21 added turn-rate arg (default = TURN_RATE_TARGET_DEGPERSEC)
{
	//Purpose: Make a numDeg CW or CCW 'spin' turn
	//Inputs:
	//	b_ccw - True if turn is to be ccw, false otherwise
	//	numDeg - angle to be swept out in the turn
	//	ROLLING_TURN_MAX_SEC_PER_DEG = const used to generate timeout proportional to turn deg
	//	IMUHdgValDeg = IMU heading value updated by UpdateIMUHdgValDeg() //11/02/20 now updated in ISR
	//	degPerSec = float value denoting desired turn rate
	//Plan:
	//	Step1: Get current heading as starting point
	//	Step2: Disable TIMER5 interrupts
	//	Step3: Compute new target value & timeout value
	//	Step4: Run motors until target reached, using inline PID algorithm to control turn rate
	//	Step5: Re-enable TIMER5 interrupts
	//Notes:
	//	06/06/21 we-written to remove PID library - now uses custom 'PIDCalcs()' function
	//	06/06/21 added re-try for 180.00 return from IMU - could be bad value
	//	06/11/21 added code to correct dHdg errors due to 179/-179 transition & bad IMU values
	//	06/12/21 cleaned up & commented out debug code

	float tgt_deg;
	float timeout_sec;
	bool bDoneTurning = false;
	bool bTimedOut = false;
	bool bResult = true; //04/21/20 added so will be only one exit point

	//DEBUG!!
	mySerial.printf("In SpinTurn(%s, %2.2f, %2.2f)\n", b_ccw == TURNDIR_CCW ? "CCW" : "CW", numDeg, degPersec);
	//DEBUG!!
	//mySerial.printf("TurnRatePID started with Kp/Ki/Kd = %2.1f,%2.1f,%2.1f, SampleTime(mSec) = %d\n",
	//	TurnRate_Kp, TurnRate_Ki, TurnRate_Kd, TURN_RATE_UPDATE_INTERVAL_MSEC);

	//no need to continue if the IMU isn't available
	if (!dmpReady)
	{
		return false;
	}

	//Step1: Get current heading as starting point
		//06/06/21 it is possible for IMU to return 180.00 on failure
		//so try again.  If it really IS 180, then 
		//it will eventually time out and go on
	int retries = 0;
	if (IMUHdgValDeg == 180.f && retries < 5)
	{
		//DEBUG!!
		mySerial.printf("Got 180.00 exactly from IMU - retrying...\n");
		//DEBUG!!
		UpdateIMUHdgValDeg();
		retries++;
		delay(30);
	}

	//Step2: Compute new target value & timeout value
	timeout_sec = 3 * numDeg / degPersec; //05/29/21 rev to use new turn rate parmeter

	//05/17/20 limit timeout_sec to 1 sec or more
	timeout_sec = (timeout_sec < 1) ? 1.f : timeout_sec;

	UpdateIMUHdgValDeg();

	//12/05/19 added #define back in to manage which direction increases yaw values
#ifdef MPU6050_CCW_INCREASES_YAWVAL
	tgt_deg = b_ccw ? IMUHdgValDeg + numDeg : IMUHdgValDeg - numDeg;
#else
	tgt_deg = b_ccw ? IMUHdgValDeg - numDeg : IMUHdgValDeg + numDeg;

#endif // MPU6050_CCW_INCREASES_YAWVAL

	//correct for -180/180 transition
	if (tgt_deg < -180)
	{
		tgt_deg += 360;
	}

	//07/29/19 bugfix
	if (tgt_deg > 180)
	{
		tgt_deg -= 360;
	}

	//DEBUG!!
	mySerial.printf("Init hdg = %4.2f deg, Turn = %4.2f  deg, tgt = %4.2f deg, timeout = %4.2f sec\n\n",
		IMUHdgValDeg, numDeg, tgt_deg, timeout_sec);
	//DEBUG!!

	double curHdgMatchVal = 0;

	//09/08/18 added to bolster end-of-turn detection
	float prevHdgMatchVal = 0;
	float matchSlope = 0;


	//Step2: Disable TIMER5 interrupts
	TIMSK5 = 0; //disable timer compare interrupt

	//Step3: Run motors until target reached, using PID algorithm to control turn rate
	Prev_HdgDeg = IMUHdgValDeg; //06/10/21 synch Prev_HdgDeg & IMUHdgValDeg just before entering loop

	//DEBUG!!
	//mySerial.printf("Just before while() loop: hdg/prvhdg = %2.2f\t%2.2f\n\n", IMUHdgValDeg, Prev_HdgDeg);

	//mySerial.printf("Msec\tHdg\tPrvHdg\tDhdg\trate\tSet\terror\tKp*err\tKi*err\tKd*Din\tOutput\n");
	//DEBUG!!

	elapsedMillis sinceLastTimeCheck = 0;
	elapsedMillis sinceLastComputeTime = 0;
	double lastError = 0;
	double lastInput = 0;
	double lastIval = 0;
	double lastDerror = 0;
	bool bFirstIMUHdg = true;

	while (!bDoneTurning && !bTimedOut)
	{
		//11/06/20 now just loops between ISR hits
		CheckForUserInput();

		//runs every 30mSec
		if (sinceLastComputeTime >= TURN_RATE_UPDATE_INTERVAL_MSEC)
		{
			sinceLastComputeTime -= TURN_RATE_UPDATE_INTERVAL_MSEC;

			UpdateIMUHdgValDeg(); //update IMUHdgValDeg

			double dHdg = IMUHdgValDeg - Prev_HdgDeg;
			if (dHdg > 180)
			{
				dHdg -= 360;
				mySerial.printf("dHdg > 180 (%2.2f - %2.2f) - subtracting 360\n", IMUHdgValDeg, Prev_HdgDeg);
			}
			else if (dHdg < -180)
			{
				dHdg += 360;
				mySerial.printf("dHdg < -180 (%2.2f - %2.2f) - adding 360\n", IMUHdgValDeg, Prev_HdgDeg);
			}

			//watch for turn rates that are wildly off
			double rate = abs(1000 * dHdg / TURN_RATE_UPDATE_INTERVAL_MSEC);
			if (rate > 3 * degPersec)
			{
				//DEBUG!!
				mySerial.printf("hdg/prevhdg/dHdg/rate = %2.2f\t%2.2f\t%2.2f\t%2.2f, excessive rate - replacing with %2.2f\n", IMUHdgValDeg, Prev_HdgDeg, dHdg, rate, degPersec);
				//DEBUG!!
				rate = degPersec;
			}

			//06/11/21 don't do calcs first time through, as Prev_HdgDeg isn't valid yet
			if (bFirstIMUHdg)
			{
				bFirstIMUHdg = false;
				Prev_HdgDeg = IMUHdgValDeg; //re-synch prev to curr hdg for next time
			}
			else
			{
				PIDCalcs(rate, degPersec, TURN_RATE_UPDATE_INTERVAL_MSEC, lastError, lastInput, lastIval, lastDerror, TurnRate_Kp, TurnRate_Ki, TurnRate_Kd, TurnRatePIDOutput);

				int speed = 0;

				(TurnRatePIDOutput > MOTOR_SPEED_MAX) ? speed = MOTOR_SPEED_MAX : speed = (int)TurnRatePIDOutput;
				(TurnRatePIDOutput <= MOTOR_SPEED_LOW) ? speed = MOTOR_SPEED_LOW : speed = (int)TurnRatePIDOutput;

				SetLeftMotorDirAndSpeed(!b_ccw, speed);
				SetRightMotorDirAndSpeed(b_ccw, speed);

				//check for nearly there and all the way there
				curHdgMatchVal = GetHdgMatchVal(tgt_deg, IMUHdgValDeg);
				matchSlope = curHdgMatchVal - prevHdgMatchVal;
				prevHdgMatchVal = curHdgMatchVal;

				//DEBUG!!
				//mySerial.printf("%lu\t%2.2f\t%2.2f\t%2.2f\t%2.2f\t%2.2f\t%2.2f\t%2.2f\t%2.2f\t%2.2f\t%d\n", 
				//	millis(), 
				//	IMUHdgValDeg,
				//	Prev_HdgDeg,
				//	dHdg,
				//	rate,
				//	degPersec, 
				//	lastError, 
				//	TurnRate_Kp * lastError,
				//	TurnRate_Ki * lastIval,
				//	TurnRate_Kd * lastDerror,
				//	speed);
				//DEBUG!!

				Prev_HdgDeg = IMUHdgValDeg; //re-synch prev to curr hdg for next time

				//look for full match
				bDoneTurning = (curHdgMatchVal >= HDG_FULL_MATCH_VAL
					|| (curHdgMatchVal >= HDG_MIN_MATCH_VAL && matchSlope < -0.1)); //have to use < vs <= as slope == 0 at start
			}
		}

		bTimedOut = (sinceLastTimeCheck > timeout_sec * 1000);

		if (bTimedOut)
		{
			//DEBUG!!
			mySerial.printf("timed out with yaw = %3.2f, tgt = %3.2f, and match = %1.3f\n", IMUHdgValDeg, tgt_deg, curHdgMatchVal);
			//DEBUG!!

			bResult = false;
		}
	}

	//DEBUG!!
	mySerial.printf("%lu: Exiting SpinTurn() at %3.2f deg\n", millis(), IMUHdgValDeg);
	//DEBUG!!

//Step4: Re-enable TIMER5 interrupts
	TIMSK5 |= (1 << OCIE5A);// enable timer compare interrupt

	StopBothMotors();
	//delay(1000); //added 04/27/21 for debug
	return bResult;
}

//bool SpinTurnToSteerVal(bool b_ccw, float tgtSteerVal, float degPersec) //04/25/21 added turn-rate arg (default = TURN_RATE_TARGET_DEGPERSEC)
//{
//	//Purpose: Make a rate-controlled CW or CCW 'spin' turn to a desired steering value
//	//Inputs:
//	//	b_ccw - True if turn is to be ccw, false otherwise
//	//	steerval - steering value to be met
//	//	ROLLING_TURN_MAX_SEC_PER_DEG = const used to generate timeout proportional to turn deg
//	//	IMUHdgValDeg = IMU heading value updated by UpdateIMUHdgValDeg() //11/02/20 now updated in ISR
//	//	degPerSec = float value denoting desired turn rate
//	//Plan:
//	//	Step1: Get current heading as starting point
//	//	Step2: Disable TIMER5 interrupts
//	//	Step4: Run motors until target steering value reached, using inline PID algorithm to control turn rate
//	//	Step5: Re-enable TIMER5 interrupts
//	//Notes:
//	//	copied from SpinTurn() and modifed to terminate on steering value
//
//	//float tgt_deg;
//	float timeout_sec;
//	bool bDoneTurning = false;
//	bool bTimedOut = false;
//	bool bResult = true; //04/21/20 added so will be only one exit point
//
//	////DEBUG!!
//	//mySerial.printf("In SpinTurn(%s, %2.2f, %2.2f)\n", b_ccw == TURNDIR_CCW ? "CCW" : "CW", numDeg, degPersec);
//	////DEBUG!!
//	mySerial.printf("TurnRatePID started with Kp/Ki/Kd = %2.1f,%2.1f,%2.1f, SampleTime(mSec) = %d\n",
//		TurnRate_Kp, TurnRate_Ki, TurnRate_Kd, TURN_RATE_UPDATE_INTERVAL_MSEC);
//
//	//no need to continue if the IMU isn't available
//	if (!dmpReady)
//	{
//		return false;
//	}
//
//	//Step1: Get current heading as starting point
//		//06/06/21 it is possible for IMU to return 180.00 on failure
//		//so try again.  If it really IS 180, then 
//		//it will eventually time out and go on
//	int retries = 0;
//	if (IMUHdgValDeg == 180.f && retries < 5)
//	{
//		//DEBUG!!
//		//mySerial.printf("Got 180.00 exactly from IMU - retrying...\n");
//		//DEBUG!!
//		UpdateIMUHdgValDeg();
//		retries++;
//		delay(30);
//	}
//
//	////Step2: Compute new target value & timeout value
//	//timeout_sec = 3 * numDeg / degPersec; //05/29/21 rev to use new turn rate parmeter
//
//	////05/17/20 limit timeout_sec to 1 sec or more
//	//timeout_sec = (timeout_sec < 1) ? 1.f : timeout_sec;
//
//	UpdateIMUHdgValDeg();
//
////	//12/05/19 added #define back in to manage which direction increases yaw values
////#ifdef MPU6050_CCW_INCREASES_YAWVAL
////	tgt_deg = b_ccw ? IMUHdgValDeg + numDeg : IMUHdgValDeg - numDeg;
////#else
////	tgt_deg = b_ccw ? IMUHdgValDeg - numDeg : IMUHdgValDeg + numDeg;
////
////#endif // MPU6050_CCW_INCREASES_YAWVAL
////
////	//correct for -180/180 transition
////	if (tgt_deg < -180)
////	{
////		tgt_deg += 360;
////	}
////
////	//07/29/19 bugfix
////	if (tgt_deg > 180)
////	{
////		tgt_deg -= 360;
////	}
//
//	//DEBUG!!
//	//mySerial.printf("Init hdg = %4.2f deg, Turn = %4.2f  deg, tgt = %4.2f deg, timeout = %4.2f sec\n\n",
//	//	IMUHdgValDeg, numDeg, tgt_deg, timeout_sec);
//	//DEBUG!!
//
//	//float curHdgMatchVal = 0;
//
//	////09/08/18 added to bolster end-of-turn detection
//	//float prevHdgMatchVal = 0;
//	//float matchSlope = 0;
//
//
//	//Step2: Disable TIMER5 interrupts
//	TIMSK5 = 0; //disable timer compare interrupt
//
//	//Step3: Run motors until target reached, using PID algorithm to control turn rate
//	Prev_HdgDeg = IMUHdgValDeg; //06/10/21 synch Prev_HdgDeg & IMUHdgValDeg just before entering loop
//
//	//DEBUG!!
//	//mySerial.printf("Just before while() loop: hdg/prvhdg = %2.2f\t%2.2f\n\n", IMUHdgValDeg, Prev_HdgDeg);
//
//	//mySerial.printf("Msec\tHdg\tPrvHdg\tDhdg\trate\tSet\terror\tKp*err\tKi*err\tKd*Din\tOutput\n");
//	//DEBUG!!
//
//	elapsedMillis sinceLastTimeCheck = 0;
//	elapsedMillis sinceLastComputeTime = 0;
//	double lastError = 0;
//	double lastInput = 0;
//	double lastIval = 0;
//	double lastDerror = 0;
//	bool bFirstIMUHdg = true;
//
//	//while (!bDoneTurning && !bTimedOut)
//	while (!bDoneTurning)
//	{
//		//11/06/20 now just loops between ISR hits
//		CheckForUserInput();
//
//		//runs every 30mSec
//		if (sinceLastComputeTime >= TURN_RATE_UPDATE_INTERVAL_MSEC)
//		{
//			sinceLastComputeTime -= TURN_RATE_UPDATE_INTERVAL_MSEC;
//
//			UpdateIMUHdgValDeg(); //update IMUHdgValDeg
//
//			double dHdg = IMUHdgValDeg - Prev_HdgDeg;
//			if (dHdg > 180)
//			{
//				dHdg -= 360;
//				mySerial.printf("dHdg > 180 - subtracting 360\n");
//			}
//			else if (dHdg < -180)
//			{
//				dHdg += 360;
//				mySerial.printf("dHdg < -180 - adding 360\n");
//			}
//
//			//watch for turn rates that are wildly off
//			double rate = abs(1000 * dHdg / TURN_RATE_UPDATE_INTERVAL_MSEC);
//			if (rate > 3 * degPersec)
//			{
//				//DEBUG!!
//				//mySerial.printf("hdg/prevhdg/dHdg/rate = %2.2f\t%2.2f\t%2.2f\t%2.2f, excessive rate - replacing with %2.2f\n", IMUHdgValDeg, Prev_HdgDeg, dHdg, rate, degPersec);
//				//DEBUG!!
//				rate = degPersec;
//			}
//
//			//06/11/21 don't do calcs first time through, as Prev_HdgDeg isn't valid yet
//			if (bFirstIMUHdg)
//			{
//				bFirstIMUHdg = false;
//				Prev_HdgDeg = IMUHdgValDeg; //re-synch prev to curr hdg for next time
//			}
//			else
//			{
//				PIDCalcs(rate, degPersec, TURN_RATE_UPDATE_INTERVAL_MSEC, lastError, lastInput, lastIval, lastDerror, TurnRate_Kp, TurnRate_Ki, TurnRate_Kd, TurnRatePIDOutput);
//
//				int speed = 0;
//
//				(TurnRatePIDOutput > MOTOR_SPEED_MAX) ? speed = MOTOR_SPEED_MAX : speed = (int)TurnRatePIDOutput;
//				(TurnRatePIDOutput <= MOTOR_SPEED_LOW) ? speed = MOTOR_SPEED_LOW : speed = (int)TurnRatePIDOutput;
//
//				SetLeftMotorDirAndSpeed(!b_ccw, speed);
//				SetRightMotorDirAndSpeed(b_ccw, speed);
//
//				//check for nearly there and all the way there
//				//curHdgMatchVal = GetHdgMatchVal(tgt_deg, IMUHdgValDeg);
//				//matchSlope = curHdgMatchVal - prevHdgMatchVal;
//				//prevHdgMatchVal = curHdgMatchVal;
//
//				//DEBUG!!
//				mySerial.printf("%lu\t%2.2f\t%2.2f\t%2.2f\t%2.2f\t%2.2f\t%2.2f\t%2.2f\t%2.2f\t%2.2f\t%d\n", 
//					millis(), 
//					IMUHdgValDeg,
//					Prev_HdgDeg,
//					dHdg,
//					rate,
//					degPersec, 
//					lastError, 
//					TurnRate_Kp * lastError,
//					TurnRate_Ki * lastIval,
//					TurnRate_Kd * lastDerror,
//					speed);
//				//DEBUG!!
//
//				Prev_HdgDeg = IMUHdgValDeg; //re-synch prev to curr hdg for next time
//
//				//look for full match
//				GetRequestedVL53l0xValues(VL53L0X_ALL);
//				bDoneTurning = (abs(LeftSteeringVal - tgtSteerVal) <= RATIO_TURN_MATCH_THRESHOLD);
//			}
//		}
//
//		//bTimedOut = (sinceLastTimeCheck > timeout_sec * 1000);
//
//		//if (bTimedOut)
//		//{
//		//	//DEBUG!!
//		//	//mySerial.printf("timed out with yaw = %3.2f, tgt = %3.2f, and match = %1.3f\n", IMUHdgValDeg, tgt_deg, curHdgMatchVal);
//		//	//DEBUG!!
//
//		//	bResult = false;
//		//}
//	}
//
//	//DEBUG!!
//	//mySerial.printf("%lu: Exiting SpinTurn() at %3.2f deg\n", millis(), IMUHdgValDeg);
//	//DEBUG!!
//
////Step4: Re-enable TIMER5 interrupts
//	TIMSK5 |= (1 << OCIE5A);// enable timer compare interrupt
//
//	StopBothMotors();
//	delay(1000); //added 04/27/21 for debug
//	return bResult;
//}

void PIDCalcs(double input, double setpoint, uint16_t sampleTime, double& lastError, double& lastInput, double& lastIval, double& lastDerror, double Kp, double Ki, double Kd, double& output)
{
	//Purpose:  Encapsulate PID algorithm so can get rid of PID library. Library too cumbersome and won't synch with TIMER5 ISR
	//Inputs:
	//	input = double denoting current input value (turn rate, speed, whatever)
	//	setpoint = double denoting desired setpoint in same units as input
	//	sampleTime = int denoting sample time to be used in calcs.
	//	lastError = ref to double denoting error saved from prev calc
	//	lastInput = ref to double denoting input saved from prev calc
	//	Kp/Ki/Kd = doubles denoting PID values to be used for calcs
	//	Output = ref to double denoting output from calc

	double error = setpoint - input;
	double dInput = (input - lastInput);
	lastIval += (error);
	double dErr = (error - lastError);

	//mySerial.printf("PIDCalcs: error/dInput/lastIval/dErr/kp/ki/kd = %2.2f\t%2.2f\t%2.2f\t%2.2f\t%2.2f\t%2.2f\t%2.2f\n", error, dInput, lastIval, dErr,
	//	Kp,Ki,Kd);

	/*Compute PID Output*/
	output = Kp * error + Ki * lastIval + Kd * dErr;

	/*Remember some variables for next time*/
	lastError = error;
	lastInput = input;
	lastDerror = dErr;
}
#pragma endregion HDG_BASED_TURN_SUPPORT

bool GetRequestedVL53l0xValues(VL53L0X_REQUEST which)
{
	//Purpose: Obtain VL53L0X ToF sensor data from Teensy sensor handler
	//Inputs: 
	//	which = VL53L0X_REQUEST value denoting which combination of value to retrieve
	//		VL53L0X_CENTERS_ONLY -> Just the left/right center sensor values
	//		VL53L0X_RIGHT -> All three right sensor values, in front/center/rear order
	//		VL53L0X_LEFT -> All three left sensor values, in front/center/rear order
	//		VL53L0X_ALL -> All seven sensor values, in left/right front/center/rear/rear order
	//		VL53L0X_REAR_ONLY -> added 10/24/20 Just the rear sensor reading

	//Outputs: 
	//	Requested sensor values, obtained via I2C from the VL53L0X sensor handler
	//	Returns TRUE if data retrieval successful, otherwise FALSE
	//Plan:
	//	Step1: Send request to VL53L0X handler
	//	Step2: get the requested data
	//Notes:
	// Copied from FourWD_WallE2_V4.ino's IsIRBeamAvail() and adapted
		// 08/05/20 added a VL53L0X_ALL request type
		// 01/24/21 added error detection/reporting

	//Step1: Send request to VL53L0X handler
	//DEBUG!!
		//mySerial.printf("Sending %d to slave\n", which);
	//DEBUG!!

	//mySerial.printf("In GetRequestedVL53l0xValues(%d)\n", (int)which);

	Wire.beginTransmission(VL53L0X_I2C_SLAVE_ADDRESS);
	I2C_writeAnything((uint8_t)which);
	Wire.endTransmission();


	//Step2: get the requested data
	int readResult = 0;
	int data_size = 0;
	switch (which)
	{
	case VL53L0X_READYCHECK: //11/10/20 added to prevent bad reads during Teensy setup()
		Wire.requestFrom(VL53L0X_I2C_SLAVE_ADDRESS, (int)(sizeof(bVL53L0X_TeensyReady)));
		readResult = I2C_readAnything(bVL53L0X_TeensyReady);
		break;

	case VL53L0X_CENTERS_ONLY:
		//just two data values needed here
		data_size = 2 * sizeof(int);
		Wire.requestFrom(VL53L0X_I2C_SLAVE_ADDRESS, (int)(2 * sizeof(Lidar_RightCenter)));
		readResult = I2C_readAnything(Lidar_RightCenter);

		if (readResult > 0)
		{
			I2C_readAnything(Lidar_LeftCenter);
		}

		//DEBUG!!
				//mySerial.printf("VL53L0X_CENTERS_ONLY case: Got LC/RC = %d, %d\n", Lidar_LeftCenter, Lidar_RightCenter);
		//DEBUG!!

		break;
	case VL53L0X_RIGHT:
		//four data values needed here
		data_size = 3 * sizeof(int) + sizeof(float);

		//DEBUG!!
				//mySerial.printf("data_size = %d\n", data_size);
		//DEBUG!!

		Wire.requestFrom(VL53L0X_I2C_SLAVE_ADDRESS, data_size);
		readResult = I2C_readAnything(Lidar_RightFront);

		if (readResult > 0)
		{
			readResult = I2C_readAnything(Lidar_RightCenter);
		}
		if (readResult > 0)
		{
			readResult = I2C_readAnything(Lidar_RightRear);
		}
		if (readResult > 0)
		{
			readResult = I2C_readAnything(RightSteeringVal);
		}

		//DEBUG!!
				//mySerial.printf("VL53L0X_RIGHT case: Got L/C/R/S = %d, %d, %d, %3.2f\n",
				//	Lidar_RightFront, Lidar_RightCenter, Lidar_RightRear, ToFSteeringVal);
		//DEBUG!!

		break;
	case VL53L0X_LEFT:
		//four data values needed here
		data_size = 3 * sizeof(int) + sizeof(float);

		Wire.requestFrom(VL53L0X_I2C_SLAVE_ADDRESS, data_size);
		readResult = I2C_readAnything(Lidar_LeftFront);

		if (readResult > 0)
		{
			readResult = I2C_readAnything(Lidar_LeftCenter);
		}
		if (readResult > 0)
		{
			readResult = I2C_readAnything(Lidar_LeftRear);
		}
		if (readResult > 0)
		{
			readResult = I2C_readAnything(LeftSteeringVal);
		}

		//DEBUG!!
				//mySerial.printf("VL53L0X_RIGHT case: Got L/C/R/S = %d, %d, %d, %3.2f\n",
				//	Lidar_LeftFront, Lidar_LeftCenter, Lidar_LeftRear, ToFSteeringVal);
		//DEBUG!!

		break;
	case VL53L0X_ALL: //added 08/05/20, chg to VL53L0X_ALL 10/31/20
		//nine data values needed here - 7 ints and 2 floats
		data_size = 7 * sizeof(int) + 2 * sizeof(float); //10/31/20 added rear distance

		//mySerial.printf("In VL53L0X_ALL case with data_size = %d\n", data_size);

		Wire.requestFrom(VL53L0X_I2C_SLAVE_ADDRESS, data_size);

		//Lidar_LeftFront
		readResult = I2C_readAnything(Lidar_LeftFront);
		if (readResult != sizeof(Lidar_LeftFront))
		{
			mySerial.printf("Error reading Lidar_LeftFront\n");
		}

		//Lidar_LeftCenter
		readResult = I2C_readAnything(Lidar_LeftCenter);
		if (readResult != sizeof(Lidar_LeftCenter))
		{
			mySerial.printf("Error reading Lidar_LeftCenter\n");
		}

		//Lidar_LeftRear
		readResult = I2C_readAnything(Lidar_LeftRear);
		if (readResult != sizeof(Lidar_LeftRear))
		{
			mySerial.printf("Error reading Lidar_LeftRear\n");
		}

		//LeftSteeringVal
		readResult = I2C_readAnything(LeftSteeringVal);
		if (readResult != sizeof(LeftSteeringVal))
		{
			mySerial.printf("Error reading LeftSteeringVal\n");
		}

		//Lidar_RightFront
		readResult = I2C_readAnything(Lidar_RightFront);
		if (readResult != sizeof(Lidar_RightFront))
		{
			mySerial.printf("Error reading Lidar_RightFront\n");
		}

		//Lidar_RightCenter
		readResult = I2C_readAnything(Lidar_RightCenter);
		if (readResult != sizeof(Lidar_RightCenter))
		{
			mySerial.printf("Error reading Lidar_RightCenter\n");
		}

		//Lidar_RightRear
		readResult = I2C_readAnything(Lidar_RightRear);
		if (readResult != sizeof(Lidar_RightRear))
		{
			mySerial.printf("Error reading Lidar_RightRear\n");
		}

		//RightSteeringVal
		readResult = I2C_readAnything(RightSteeringVal);
		if (readResult != sizeof(RightSteeringVal))
		{
			mySerial.printf("Error reading LeftSteeringVal\n");
		}

		//Lidar_Rear
		readResult = I2C_readAnything(Lidar_Rear);
		if (readResult != sizeof(Lidar_Rear))
		{
			mySerial.printf("Error reading Lidar_Rear\n");
		}

		//mySerial.printf("%lu: VL53l0x - %d, %d, %d, %d, %d, %d, %d\n",
		//	millis(), 
		//	Lidar_LeftFront, Lidar_LeftCenter, Lidar_LeftRear,
		//	Lidar_RightFront, Lidar_RightCenter, Lidar_RightRear,
		//	Lidar_Rear);
		break; //10/31/20 bugfix

	case VL53L0X_REAR_ONLY:
		//just ONE data value needed here
		data_size = sizeof(int);
		Wire.requestFrom(VL53L0X_I2C_SLAVE_ADDRESS, (int)(sizeof(Lidar_Rear)));
		readResult = I2C_readAnything(Lidar_Rear);

		//DEBUG!!
				//mySerial.printf("VL53L0X_REAR_ONLY case: Got Rear = %d\n", Lidar_Rear);
		//DEBUG!!

		break;

	default:
		break;
	}

	return readResult > 0; //this is true only if all reads succeed
}

void WaitForVL53L0XTeensy()
{
	bVL53L0X_TeensyReady = false;
	while (!bVL53L0X_TeensyReady)
	{
		GetRequestedVL53l0xValues(VL53L0X_READYCHECK); //this updates bVL53L0X_TeensyReady
		//mySerial.printf("%lu: got %d from VL53L0X Teensy\n", millis(), bVL53L0X_TeensyReady);
		delay(100);
	}

	Serial.print(F("Teensy setup() finished at ")); Serial.printf("%lu mSec\n", millis());

	//now try to get a VL53L0X measurement
	//11/08/20 rev to loop until all distance sensors provide valid data
	//mySerial.printf("Msec\tLFront\tLCtr\tLRear\tRFront\tRCtr\tRRear\tRear\n");

	//mySerial.printf("%lu: %d\t%d\t%d\t%d\t%d\t%d\t%d\n",
	//	millis(), Lidar_LeftFront, Lidar_LeftCenter, Lidar_LeftRear,
	//	Lidar_RightFront, Lidar_RightCenter, Lidar_RightRear, Lidar_Rear);

	while (Lidar_LeftFront <= 0 || Lidar_LeftCenter <= 0 || Lidar_LeftRear <= 0
		|| Lidar_LeftFront <= 0 || Lidar_LeftCenter <= 0 || Lidar_LeftRear <= 0
		|| Lidar_Rear <= 0)
	{
		////values updated 10 times/sec in ISR
		mySerial.printf("%lu: %d\t%d\t%d\t%d\t%d\t%d\t%d\n",
			millis(), Lidar_LeftFront, Lidar_LeftCenter, Lidar_LeftRear,
			Lidar_RightFront, Lidar_RightCenter, Lidar_RightRear, Lidar_Rear);

		delay(100);
	}

	mySerial.printf("VL53L0X Teensy Ready at %lu\n\n", millis());
}

double GetSteeringAngle(double steerval)
{
	//Purpose:  Convert a steering angle into the equivalent off-parallel orientation in degrees
	//Inputs:
	//	steerval = double value denoting current steering value
	//	Notes:
	//	06/27/21 now steering_val/off_angle slope is a constant 0.0175
	const double slopeval = 0.0175;
	double offparalleldeg = steerval / slopeval; //e.g. for steerval = -0.187 @ 10cm offset, returns +21deg
	//mySerial.printf("GetSteeringAngle(%d, %2.4f): slopeval = %2.4f, res %2.2f\n", ctrdist_cm, steerval, slopeval, offparalleldeg);
	return offparalleldeg;
}

//11/05/15 added to get LIDAR measurement
int GetFrontDistCm()
{
	//Notes:
	//	12/05/15 chg to MODE line vs I2C
	//	01/06/16 rev to return avg of prev distances on error 

#ifndef NO_LIDAR
	unsigned long pulse_width;
	int LIDARdistCm;

	pulse_width = pulseIn(LIDAR_MODE_PIN, HIGH); // Count how long the pulse is high in microseconds
	LIDARdistCm = pulse_width / 10; // 10usec = 1 cm of distance for LIDAR-Lite

	//chk for erroneous reading
	if (LIDARdistCm == 0)
	{
		//replace with average of last three readings from aFrontDist
		int avgdist = GetAvgFrontDistCm();
		mySerial.printf("%lu: Error in GetFrontDistCm() - %d replaced with %d\n", millis(), LIDARdistCm, avgdist);
		LIDARdistCm = avgdist;
	}

	//04/30/17 added limit detection/correction
	LIDARdistCm = (LIDARdistCm > 0) ? LIDARdistCm : MAX_FRONT_DISTANCE_CM;

	return LIDARdistCm;
#else
	return 10; //safe number, I hope
#endif
}

//04/25/21 rewritten to use aFrontDist[] values
float GetAvgFrontDistCm()
{
	int avgdist = 0;
	for (int i = 0; i < FRONT_DIST_AVG_WINDOW_SIZE; i++)
	{
		//DEBUG!!
		//mySerial.printf("frontdist[%d] = %d\n", FRONT_DIST_ARRAY_SIZE - 1 - i, aFrontDist[FRONT_DIST_ARRAY_SIZE - 1 - i]);
		//DEBUG!!
		avgdist += aFrontDist[FRONT_DIST_ARRAY_SIZE - 1 - i];
	}
	//DEBUG!!
	//mySerial.printf("avgdisttot = %d\n", avgdist);
	//DEBUG!!

	avgdist = (int)((float)avgdist / (float)FRONT_DIST_AVG_WINDOW_SIZE);
	//DEBUG!!
	//mySerial.printf("avgdist = %d\n", avgdist);
	//DEBUG!!
	return avgdist;
}

//08/12/20 Extracted inline FRONT_DIST_ARRAY init code so can be called from anywhere
void InitFrontDistArray()
{
	//04/01/15 initialize 'stuck detection' arrays
	//06/17/20 re-wrote for better readability
	//to ensure var > STUCK_FRONT_VARIANCE_THRESHOLD for first FRONT_DIST_ARRAY_SIZE loops
	//array is initialized with sawtooth from 0 to MAX_FRONT_DISTANCE_CM
	int newval = 0;
	int bumpval = MAX_FRONT_DISTANCE_CM / FRONT_DIST_ARRAY_SIZE;
	bool bgoingUp = true;

	for (int i = 0; i < FRONT_DIST_ARRAY_SIZE; i++)
	{
		aFrontDist[i] = newval;
		//DEBUG!!
		//mySerial.printf("i = %d, newval = %d, aFrontdist[%d] = %d\n", i, newval, i, aFrontDist[i]);
		//DEBUG!!
		if (bgoingUp)
		{

			if (newval < MAX_FRONT_DISTANCE_CM - bumpval) //don't want newval > MAX_FRONT_DISTANCE_CM
			{
				newval += bumpval;
			}
			else
			{
				bgoingUp = false;
			}
		}
		else
		{
			if (newval > bumpval) //don't want newval < 0
			{
				newval -= bumpval;
			}
			else
			{
				bgoingUp = true;
			}
		}
	}

	//04/19/19 init Front_Dist_PrevVMean  & Front_Dist_PrevVar to mean/var respectively
	long sum = 0;
	for (int i = 0; i < FRONT_DIST_ARRAY_SIZE; i++)
	{
		sum += aFrontDist[i]; //adds in rest of values
	}
	Front_Dist_PrevVMean = (float)sum / (float)FRONT_DIST_ARRAY_SIZE;

	//	Step2: calc new 'brute force' variance
	float sumsquares = 0;
	for (int i = 0; i < FRONT_DIST_ARRAY_SIZE; i++)
	{
		sumsquares += (aFrontDist[i] - Front_Dist_PrevVMean) * (aFrontDist[i] - Front_Dist_PrevVMean);
	}

	Front_Dist_PrevVar = sumsquares / FRONT_DIST_ARRAY_SIZE;
	mySerial.printf("%lu: aFrontDist Init: Front_Dist_PrevVMean = %3.2f, Front_Dist_PrevVar = %3.2f\n", millis(), Front_Dist_PrevVMean, Front_Dist_PrevVar);
	frontvar = Front_Dist_PrevVar; //added 03/30/21 to prevent 'stuck' at startup
}

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

214

215

216

217

218

219

220

221

222

223

224

225

226

227

228

229

230

231

232

233

234

235

236

237

238

239

240

241

242

243

244

245

246

247

248

249

250

251

252

253

254

255

256

257

258

259

260

261

262

263

264

265

266

267

268

269

270

271

272

273

274

275

276

277

278

279

280

281

282

283

284

285

286

287

288

289

290

291

292

293

294

295

296

297

298

299

300

301

302

303

304

305

306

307

308

309

310

311

312

313

314

315

316

317

318

319

320

321

322

323

324

325

326

327

328

329

330

331

332

333

334

335

336

337

338

339

340

341

342

343

344

345

346

347

348

349

350

351

352

353

354

355

356

357

358

359

360

361

362

363

364

365

366

367

368

369

370

371

372

373

374

375

376

377

378

379

380

381

382

383

384

385

386

387

388

389

390

391

392

393

394

395

396

397

398

399

400

401

402

403

404

405

406

407

408

409

410

411

412

413

414

415

416

417

418

419

420

421

422

423

424

425

426

427

428

429

430

431

432

433

434

435

436

437

438

439

440

441

442

443

444

445

446

447

448

449

450

451

452

453

454

455

456

457

458

459

460

461

462

463

464

465

466

467

468

469

470

471

472

473

474

475

476

477

478

479

480

481

482

483

484

485

486

487

488

489

490

491

492

493

494

495

496

497

498

499

500

501

502

503

504

505

506

507

508

509

510

511

512

513

514

515

516

517

518

519

520

521

522

523

524

525

526

527

528

529

530

531

532

533

534

535

536

537

538

539

540

541

542

543

544

545

546

547

548

549

550

551

552

553

554

555

556

557

558

559

560

561

562

563

564

565

566

567

568

569

570

571

572

573

574

575

576

577

578

579

580

581

582

583

584

585

586

587

588

589

590

591

592

593

594

595

596

597

598

599

600

601

602

603

604

605

606

607

608

609

610

611

612

613

614

615

616

617

618

619

620

621

622

623

624

625

626

627

628

629

630

631

632

633

634

635

636

637

638

639

640

641

642

643

644

645

646

647

648

649

650

651

652

653

654

655

656

657

658

659

660

661

662

663

664

665

666

667

668

669

670

671

672

673

674

675

676

677

678

679

680

681

682

683

684

685

686

687

688

689

690

691

692

693

694

695

696

697

698

699

700

701

702

703

704

705

706

707

708

709

710

711

712

713

714

715

716

717

718

719

720

721

722

723

724

725

726

727

728

729

730

731

732

733

734

735

736

737

738

739

740

741

742

743

744

745

746

747

748

749

750

751

752

753

754

755

756

757

758

759

760

761

762

763

764

765

766

767

768

769

770

771

772

773

774

775

776

777

778

779

780

781

782

783

784

785

786

787

788

789

790

791

792

793

794

795

796

797

798

799

800

801

802

803

804

805

806

807

808

809

810

811

812

813

814

815

816

817

818

819

820

821

822

823

824

825

826

827

828

829

830

831

832

833

834

835

836

837

838

839

840

841

842

843

844

845

846

847

848

849

850

851

852

853

854

855

856

857

858

859

860

861

862

863

864

865

866

867

868

869

870

871

872

873

874

875

876

877

878

879

880

881

882

883

884

885

886

887

888

889

890

891

892

893

894

895

896

897

898

899

900

901

902

903

904

905

906

907

908

909

910

911

912

913

914

915

916

917

918

919

920

921

922

923

924

925

926

927

928

929

930

931

932

933

934

935

936

937

938

939

940

941

942

943

944

945

946

947

948

949

950

951

952

953

954

955

956

957

958

959

960

961

962

963

964

965

966

967

968

969

970

971

972

973

974

975

976

977

978

979

980

981

982

983

984

985

986

987

988

989

990

991

992

993

994

995

996

997

998

999

1000

1001

1002

1003

1004

1005

1006

1007

1008

1009

1010

1011

1012

1013

1014

1015

1016

1017

1018

1019

1020

1021

1022

1023

1024

1025

1026

1027

1028

1029

1030

1031

1032

1033

1034

1035

1036

1037

1038

1039

1040

1041

1042

1043

1044

1045

1046

1047

1048

1049

1050

1051

1052

1053

1054

1055

1056

1057

1058

1059

1060

1061

1062

1063

1064

1065

1066

1067

1068

1069

1070

1071

1072

1073

1074

1075

1076

1077

1078

1079

1080

1081

1082

1083

1084

1085

1086

1087

1088

1089

1090

1091

1092

1093

1094

1095

1096

1097

1098

1099

1100

1101

1102

1103

1104

1105

1106

1107

1108

1109

1110

1111

1112

1113

1114

1115

1116

1117

1118

1119

1120

1121

1122

1123

1124

1125

1126

1127

1128

1129

1130

1131

1132

1133

1134

1135

1136

1137

1138

1139

1140

1141

1142

1143

1144

1145

1146

1147

1148

1149

1150

1151

1152

1153

1154

1155

1156

1157

1158

1159

1160

1161

1162

1163

1164

1165

1166

1167

1168

1169

1170

1171

1172

1173

1174

1175

1176

1177

1178

1179

1180

1181

1182

1183

1184

1185

1186

1187

1188

1189

1190

1191

1192

1193

1194

1195

1196

1197

1198

1199

1200

1201

1202

1203

1204

1205

1206

1207

1208

1209

1210

1211

1212

1213

1214

1215

1216

1217

1218

1219

1220

1221

1222

1223

1224

1225

1226

1227

1228

1229

1230

1231

1232

1233

1234

1235

1236

1237

1238

1239

1240

1241

1242

1243

1244

1245

1246

1247

1248

1249

1250

1251

1252

1253

1254

1255

1256

1257

1258

1259

1260

1261

1262

1263

1264

1265

1266

1267

1268

1269

1270

1271

1272

1273

1274

1275

1276

1277

1278

1279

1280

1281

1282

1283

1284

1285

1286

1287

1288

1289

1290

1291

1292

1293

1294

1295

1296

1297

1298

1299

1300

1301

1302

1303

1304

1305

1306

1307

1308

1309

1310

1311

1312

1313

1314

1315

1316

1317

1318

1319

1320

1321

1322

1323

1324

1325

1326

1327

1328

1329

1330

1331

1332

1333

1334

1335

1336

1337

1338

1339

1340

1341

1342

1343

1344

1345

1346

1347

1348

1349

1350

1351

1352

1353

1354

1355

1356

1357

1358

1359

1360

1361

1362

1363

1364

1365

1366

1367

1368

1369

1370

1371

1372

1373

1374

1375

1376

1377

1378

1379

1380

1381

1382

1383

1384

1385

1386

1387

1388

1389

1390

1391

1392

1393

1394

1395

1396

1397

1398

1399

1400

1401

1402

1403

1404

1405

1406

1407

1408

1409

1410

1411

1412

1413

1414

1415

1416

1417

1418

1419

1420

1421

1422

1423

1424

1425

1426

1427

1428

1429

1430

1431

1432

1433

1434

1435

1436

1437

1438

1439

1440

1441

1442

1443

1444

1445

1446

1447

1448

1449

1450

1451

1452

1453

1454

1455

1456

1457

1458

1459

1460

1461

1462

1463

1464

1465

1466

1467

1468

1469

1470

1471

1472

1473

1474

1475

1476

1477

1478

1479

1480

1481

1482

1483

1484

1485

1486

1487

1488

1489

1490

1491

1492

1493

1494

1495

1496

1497

1498

1499

1500

1501

1502

1503

1504

1505

1506

1507

1508

1509

1510

1511

1512

1513

1514

1515

1516

1517

1518

1519

1520

1521

1522

1523

1524

1525

1526

1527

1528

1529

1530

1531

1532

1533

1534

1535

1536

1537

1538

1539

1540

1541

1542

1543

1544

1545

1546

1547

1548

1549

1550

1551

1552

1553

1554

1555

1556

1557

1558

1559

1560

1561

1562

1563

1564

1565

1566

1567

1568

1569

1570

1571

1572

1573

1574

1575

1576

1577

1578

1579

1580

1581

1582

1583

1584

1585

1586

1587

1588

1589

1590

1591

1592

1593

1594

1595

1596

1597

1598

1599

1600

1601

1602

1603

1604

1605

1606

1607

1608

1609

1610

1611

1612

1613

1614

1615

1616

1617

1618

1619

1620

1621

1622

1623

1624

1625

1626

1627

1628

1629

1630

1631

1632

1633

1634

1635

1636

1637

1638

1639

1640

1641

1642

1643

1644

1645

1646

1647

1648

1649

1650

1651

1652

1653

1654

1655

1656

1657

1658

1659

1660

1661

1662

1663

1664

1665

1666

1667

1668

1669

1670

1671

1672

1673

1674

1675

1676

1677

1678

1679

1680

1681

1682

1683

1684

1685

1686

1687

1688

1689

1690

1691

1692

1693

1694

1695

1696

1697

1698

1699

1700

1701

1702

1703

1704

1705

1706

1707

1708

1709

1710

1711

1712

1713

1714

1715

1716

1717

1718

1719

1720

1721

1722

1723

1724

1725

1726

1727

1728

1729

1730

1731

1732

1733

1734

1735

1736

1737

1738

1739

1740

1741

1742

1743

1744

1745

1746

1747

1748

1749

1750

1751

1752

1753

1754

1755

1756

1757

1758

1759

1760

1761

1762

1763

1764

1765

1766

1767

1768

1769

1770

1771

1772

1773

1774

1775

1776

1777

1778

1779

1780

1781

1782

1783

1784

1785

1786

1787

1788

1789

1790

1791

1792

1793

1794

1795

1796

1797

1798

1799

1800

1801

1802

1803

1804

1805

1806

1807

1808

1809

1810

1811

1812

1813

1814

1815

1816

1817

1818

1819

1820

1821

1822

1823

1824

1825

1826

1827

1828

1829

1830

1831

1832

1833

1834

1835

1836

1837

1838

1839

1840

1841

1842

1843

1844

1845

1846

1847

1848

1849

1850

1851

1852

1853

1854

1855

1856

1857

1858

1859

1860

1861

1862

1863

1864

1865

1866

1867

1868

1869

1870

1871

1872

1873

1874

1875

1876

1877

1878

1879

1880

1881

1882

1883

1884

1885

1886

1887

1888

1889

1890

1891

1892

1893

1894

1895

1896

1897

1898

1899

1900

1901

1902

1903

1904

1905

1906

1907

1908

1909

1910

1911

1912

1913

1914

1915

1916

1917

1918

1919

1920

1921

1922

1923

1924

1925

1926

1927

1928

1929

1930

1931

1932

1933

1934

1935

1936

1937

1938

1939

1940

1941

1942

1943

1944

1945

1946

1947

1948

1949

1950

1951

1952

1953

1954

1955

1956

1957

1958

1959

1960

1961

1962

1963

1964

1965

1966

1967

1968

1969

1970

1971

1972

1973

1974

1975

1976

1977

1978

1979

1980

1981

1982

1983

1984

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

2010

2011

2012

2013

2014

2015

2016

2017

2018

2019

2020

2021

2022

2023

2024

2025

2026

2027

2028

2029

2030

2031

2032

2033

2034

2035

2036

2037

2038

2039

2040

2041

2042

2043

2044

2045

2046

2047

2048

2049

2050

2051

2052

2053

2054

2055

2056

2057

2058

2059

2060

2061

2062

2063

2064

2065

2066

2067

2068

2069

2070

2071

2072

2073

2074

2075

2076

2077

2078

2079

2080

2081

2082

2083

2084

2085

2086

2087

2088

2089

2090

2091

2092

2093

2094

2095

2096

2097

2098

2099

2100

2101

2102

2103

2104

2105

2106

2107

2108

2109

2110

2111

2112

2113

2114

2115

2116

2117

2118

2119

2120

2121

2122

2123

2124

2125

2126

2127

2128

2129

2130

2131

2132

2133

2134

2135

2136

2137

2138

2139

2140

2141

2142

2143

2144

2145

2146

2147

2148

2149

2150

2151

2152

2153

2154

2155

2156

2157

2158

2159

2160

2161

2162

2163

2164

2165

2166

2167

2168

2169

2170

2171

2172

2173

2174

2175

2176

2177

2178

2179

2180

2181

2182

2183

2184

2185

2186

2187

2188

2189

2190

2191

2192

2193

2194

2195

2196

2197

2198

2199

2200

2201

2202

2203

2204

2205

2206

2207

2208

2209

2210

2211

2212

2213

2214

2215

2216

2217

2218

2219

2220

2221

2222

2223

2224

2225

2226

2227

2228

2229

2230

2231

2232

2233

2234

2235

2236

2237

2238

2239

2240

2241

2242

2243

2244

2245

2246

2247

2248

2249

Name: FourWD_WallTrackTest.ino

Created: 6/18/2021 7:20:58 PM

Author: FRANKNEWXPS15\Frank

Name: FourWD_PulseTurnRateTest.ino

Created: 5/24/2021 4:49:52 PM

Author: FRANKNEWXPS15\Frank

#pragma region INCLUDES

#include <PID_v2.h>

#include <elapsedMillis.h>

#include <PrintEx.h> //allows printf-style printout syntax

#include "MPU6050_6Axis_MotionApps_V6_12.h" //changed to this version 10/05/19

#include "I2Cdev.h" //02/19/19: this includes SBWire.h

#include "I2C_Anything.h" //needed for sending float data over I2C

#pragma endregion INCLUDES

#pragma region DEFINES

#define MPU6050_I2C_ADDR 0x69

//#define DISTANCES_ONLY //added 11/14/18 to just display distances in infinite loop

#pragma endregion DEFINES

#pragma region PRE_SETUP

StreamEx mySerial = Serial; //added 03/18/18 for printf-style printing

MPU6050 mpu(MPU6050_I2C_ADDR); //06/23/18 chg to AD0 high addr, using INT connected to Mega pin 2 (INT0)

volatile int frontdistval = 0; //10/10/20 chg to volatile

volatile double frontvar = 0; //08/11/20 now updated in timer1 ISR

const int MAX_FRONT_DISTANCE_CM = 400;

const int FRONT_DIST_AVG_WINDOW_SIZE = 3; //moved here & renamed 04/28/19

const int FRONT_DIST_ARRAY_SIZE = 50; //11/22/20 doubled to acct for 10Hz update rate

uint16_t aFrontDist[FRONT_DIST_ARRAY_SIZE]; //04/18/19 rev to use uint16_t vs byte

//11/03/18 added for new incremental variance calc

double Front_Dist_PrevVar = 0;

double Front_Dist_PrevVMean = 0;

#pragma endregion PRE_SETUP

#pragma region MOTOR_PINS

//09/11/20 Now using two Adafruit DRV8871 drivers for all 4 motors

const int In1_Left = 10;

const int In2_Left = 11;

const int In1_Right = 8;

const int In2_Right = 9;

#pragma endregion Motor Pin Assignments

#pragma region MISC_PIN_ASSIGNMENTS

const int RED_LASER_DIODE_PIN = 7;

const int LIDAR_MODE_PIN = 4; //mvd here 01/10/18

#pragma endregion MISC_PIN_ASSIGNMENTS

#pragma region MOTOR_PARAMETERS

//drive wheel speed parameters

const int MOTOR_SPEED_FULL = 200; //range is 0-255

const int MOTOR_SPEED_MAX = 255; //range is 0-255

const int MOTOR_SPEED_HALF = 127; //range is 0-255

const int MOTOR_SPEED_QTR = 75; //added 09/25/20

const int MOTOR_SPEED_LOW = 50; //added 01/22/15

const int MOTOR_SPEED_OFF = 0; //range is 0-255

//drive wheel direction constants

const boolean FWD_DIR = true;

const boolean REV_DIR = !FWD_DIR;

const bool TURNDIR_CCW = true;

const bool TURNDIR_CW = false;

//Motor direction variables

boolean bLeftMotorDirIsFwd = true;

boolean bRightMotorDirIsFwd = true;

bool bIsForwardDir = true; //default is foward direction

#pragma endregion Motor Parameters

#pragma region HEADING_AND_RATE_BASED_TURN_PARAMETERS

elapsedMillis MsecSinceLastTurnRateUpdate;

const int MAX_PULSE_WIDTH_MSEC = 100;

const int MIN_PULSE_WIDTH_MSEC = 0;

const int MAX_SPIN_MOTOR_SPEED = 250;

const int MIN_SPIN_MOTOR_SPEED = 50;

const int TURN_RATE_UPDATE_INTERVAL_MSEC = 30;

double Prev_HdgDeg = 0;

float tgt_deg;

float timeout_sec;

//05/31/21 latest & greatest PID values

double TurnRate_Kp = 5.0;

double TurnRate_Ki = 1;

double TurnRate_Kd = 0.5;

double TurnRatePIDSetPointDPS, TurnRatePIDOutput;

double TurnRatePIDInput = 15.f;

PID TurnRatePID(&TurnRatePIDInput, &TurnRatePIDOutput, &TurnRatePIDSetPointDPS, TurnRate_Kp, TurnRate_Ki, TurnRate_Kd, DIRECT);

const float HDG_NEAR_MATCH_VAL = 0.8; //slow the turn down here

const float HDG_FULL_MATCH_VAL = 0.99; //stop the turn here //rev 05/17/20

const float HDG_MIN_MATCH_VAL = 0.6; //added 09/08/18: don't start checking slope until turn is well started

#pragma endregion HEADING_AND_RATE_BASED_TURN_PARAMETERS

const double RATIO_TURN_MATCH_THRESHOLD = 0.1;

#pragma region MPU6050_SUPPORT

uint8_t mpuIntStatus; // holds actual interrupt status byte from MPU. Used in Homer's Overflow routine

uint8_t devStatus; // return status after each device operation (0 = success, !0 = error)

uint16_t packetSize; // expected DMP packet size (default is 42 bytes)

uint16_t fifoCount; // count of all bytes currently in FIFO

uint8_t fifoBuffer[64]; // FIFO storage buffer

// orientation/motion vars

Quaternion q; // [w, x, y, z] quaternion container

VectorInt16 aa; // [x, y, z] accel sensor measurements

VectorInt16 aaReal; // [x, y, z] gravity-free accel sensor measurements

VectorInt16 aaWorld; // [x, y, z] world-frame accel sensor measurements

VectorFloat gravity; // [x, y, z] gravity vector

float euler[3]; // [psi, theta, phi] Euler angle container

float ypr[3]; // [yaw, pitch, roll] yaw/pitch/roll container and gravity vector

int GetPacketLoopCount = 0;

int OuterGetPacketLoopCount = 0;

//MPU6050 status flags

bool bMPU6050Ready = true;

bool dmpReady = false; // set true if DMP init was successful

volatile float IMUHdgValDeg = 0; //updated by UpdateIMUHdgValDeg()//11/02/20 now updated in ISR

const uint16_t MAX_GETPACKET_LOOPS = 100; //10/30/19 added for backup loop exit condition in GetCurrentFIFOPacket()

uint8_t GetCurrentFIFOPacket(uint8_t* data, uint8_t length, uint16_t max_loops = MAX_GETPACKET_LOOPS); //prototype here so can define a default param

bool bFirstTime = true;

#define MPU6050_CCW_INCREASES_YAWVAL //added 12/05/19

#pragma endregion MPU6050 Support

#pragma region WALL_FOLLOW_SUPPORT

const int WALL_OFFSET_TRACK_Kp = 100;

const int WALL_OFFSET_TRACK_Ki = 0;

const int WALL_OFFSET_TRACK_Kd = 0;

//const double WALL_OFFSET_TRACK_SETPOINT_LIMIT = 0.3;

//const double WALL_OFFSET_TRACK_SETPOINT_LIMIT = 0.4;

//const double WALL_OFFSET_TRACK_SETPOINT_LIMIT = 0.5;

//const double WALL_OFFSET_TRACK_SETPOINT_LIMIT = 0.15;

const double WALL_OFFSET_TRACK_SETPOINT_LIMIT = 0.25;

double WallTrackSteerVal, WallTrackOutput, WallTrackSetPoint;

const int CHG_CONNECT_LED_PIN = 50; //12/16/20 added for debug

const int WALL_OFFSET_TGTDIST_CM = 30;

double LeftSteeringVal, RightSteeringVal; //added 08/06/20

const int WALL_TRACK_UPDATE_INTERVAL_MSEC = 50;

//const int WALL_TRACK_UPDATE_INTERVAL_MSEC = 30;

#pragma endregion WALL_FOLLOW_SUPPORT

#pragma region VL53L0X LIDAR SUPPORT

//VL53L0X Sensor data values

//11/05/20 revised to make all volatile

volatile int Lidar_RightFront;

volatile int Lidar_RightCenter;

volatile int Lidar_RightRear;

volatile int Lidar_LeftFront;

volatile int Lidar_LeftCenter;

volatile int Lidar_LeftRear;

volatile int Lidar_Rear; //added 10/24/20

bool bVL53L0X_TeensyReady = false; //11/10/20 added to prevent bad data reads during Teensy setup()

enum VL53L0X_REQUEST

{

VL53L0X_READYCHECK, //added 11/10/20 to prevent bad reads during Teensy setup()

VL53L0X_CENTERS_ONLY,

VL53L0X_RIGHT,

VL53L0X_LEFT,

VL53L0X_ALL, //added 08/06/20, replaced VL53L0X_BOTH 10/31/20

VL53L0X_REAR_ONLY //added 10/24/20

};

const int VL53L0X_I2C_SLAVE_ADDRESS = 0x20; ////Teensy 3.5 VL53L0X ToF LIDAR controller

#pragma endregion VL53L0X LIDAR SUPPORT

//************************************************************************************************************************************

//*********************************************************** TIMER ISR **************************************************************

//************************************************************************************************************************************

#pragma region TIMER_ISR

#define TIMER_INT_OUTPUT_PIN 53 //scope monitor pin

bool GetRequestedVL53l0xValues(VL53L0X_REQUEST which);

volatile bool bTimeForNavUpdate = false;

const int TIMER5_INTERVAL_MSEC = 100; //05/15/21 added to eliminate magic number

int GetFrontDistCm();

ISR(TIMER5_COMPA_vect) //timer5 interrupt 5Hz

{

digitalWrite(TIMER_INT_OUTPUT_PIN, HIGH);//so I can monitor interrupt timing

delayMicroseconds(30); //leave in - so can see even with NO_STUCK defined

bTimeForNavUpdate = true;

//11/2/20 have to re-enable interrupts for I2C comms to work

interrupts();

GetRequestedVL53l0xValues(VL53L0X_ALL); //11/2/20 update all distances every 100mSec

noInterrupts();

frontdistval = GetFrontDistCm();

digitalWrite(TIMER_INT_OUTPUT_PIN, LOW);//so I can monitor interrupt timing

}

#pragma endregion TIMER_ISR

void setup()

{

Serial.begin(115200);

#pragma region MPU6050

mySerial.printf("\nChecking for MPU6050 IMU at I2C Addr 0x%x\n", MPU6050_I2C_ADDR);

mpu.initialize();

// verify connection

Serial.println(mpu.testConnection() ? F("MPU6050 connection successful") : F("MPU6050 connection failed"));

float StartSec = 0; //used to time MPU6050 init

Serial.println(F("Initializing DMP..."));

devStatus = mpu.dmpInitialize();

// make sure it worked (returns 0 if successful)

if (devStatus == 0)

{

// turn on the DMP, now that it's ready

Serial.println(F("Enabling DMP..."));

mpu.setDMPEnabled(true);

// set our DMP Ready flag so the main loop() function knows it's okay to use it

Serial.println(F("DMP ready! Waiting for MPU6050 drift rate to settle..."));

dmpReady = true;

// get expected DMP packet size for later comparison

packetSize = mpu.dmpGetFIFOPacketSize();

bMPU6050Ready = true;

StartSec = millis() / 1000.f;

mySerial.printf("MPU6050 Ready at %2.2f Sec\n", StartSec);

}

else

{

// ERROR!

// 1 = initial memory load failed

// 2 = DMP configuration updates failed

// (if it's going to break, usually the code will be 1)

Serial.print(F("DMP Initialization failed (code "));

Serial.print(devStatus);

Serial.println(F(")"));

bMPU6050Ready = false;

}

#pragma endregion MPU6050

#pragma region PIN_INITIALIZATION

pinMode(LIDAR_MODE_PIN, INPUT); // Set LIDAR input monitor pin

#pragma endregion PIN_INITIALIZATION

#pragma region TIMER_INTERRUPT

//09/18/20 can't use Timer1 cuz doing so conflicts with PWM on pins 10-12

cli();//stop interrupts

TCCR5A = 0;// set entire TCCR5A register to 0

TCCR5B = 0;// same for TCCR5B

TCNT5 = 0;//initialize counter value to 0

// 06/15/21 rewritten to use defined interval constant rather than magic number

//10/11/20 chg timer interval to 10Hz vs 5

//OCR5A = 1562;// = (16*10^6) / (10*1024) - 1 (must be <65536)

int ocr5a = (16 * 1e6) / ((1000 / TIMER5_INTERVAL_MSEC) * 1024) - 1;

mySerial.printf("ocr5a = %d\n", ocr5a);

OCR5A = ocr5a;

TCCR5B |= (1 << WGM52);// turn on CTC mode

TCCR5B |= (1 << CS52) | (1 << CS50);// Set CS10 and CS12 bits for 1024 prescaler

TIMSK5 |= (1 << OCIE5A);// enable timer compare interrupt

sei();//allow interrupts

pinMode(TIMER_INT_OUTPUT_PIN, OUTPUT);

#pragma endregion TIMER_INTERRUPT

//02/08/21 mvd below ISR enable so this section can use ISR-generated VL53L0X distances

#pragma region VL53L0X_TEENSY

mySerial.printf("Checking for Teensy 3.5 VL53L0X Controller at I2C addr 0x%x\n", VL53L0X_I2C_SLAVE_ADDRESS);

while (!bVL53L0X_TeensyReady)

{

Wire.beginTransmission(VL53L0X_I2C_SLAVE_ADDRESS);

bVL53L0X_TeensyReady = (Wire.endTransmission() == 0);

//mySerial.printf("%lu: VL53L0X Teensy Not Avail...\n", millis());

delay(100);

}

mySerial.printf("Teensy available at %lu with bVL53L0X_TeensyReady = %d. Waiting for Teensy setup() to finish\n", millis(), bVL53L0X_TeensyReady);

WaitForVL53L0XTeensy();

//mySerial.printf("VL53L0X Teensy Ready at %lu\n\n", millis());

#pragma endregion VL53L0X_TEENSY

//11/14/18 added this section for distance printout only

//08/06/20 revised for VL53L0X support

#ifdef DISTANCES_ONLY

TIMSK5 = 0;

digitalWrite(RED_LASER_DIODE_PIN, HIGH); //enable the front laser dot

mySerial.printf("\n------------ DISTANCES ONLY MODE!!! -----------------\n\n");

int i = 0; //added 09/20/20 for in-line header display

mySerial.printf("Msec\tLFront\tLCenter\tLRear\tRFront\tRCenter\tRRear\tRear\n");

while (true)

{

//if (bTimeForNavUpdate)

//{

// bTimeForNavUpdate = false;

//09/20/20 re-display the column headers

//if (++i % 20 == 0)

//{

// mySerial.printf("\nMsec\tLFront\tLCenter\tLRear\tRFront\tRCenter\tRRear\tFront\tRear\n");

//}

//commented out 02/02/21 - now done in ISR

GetRequestedVL53l0xValues(VL53L0X_ALL);

mySerial.printf("%lu\t%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d\n",

millis(), Lidar_LeftFront, Lidar_LeftCenter, Lidar_LeftRear,

Lidar_RightFront, Lidar_RightCenter, Lidar_RightRear, frontdistval, Lidar_Rear);

//}

delay(50);

}

TIMSK5 |= (1 << OCIE5A);// enable timer compare interrupt

#endif // DISTANCES_ONLY

#pragma region L/R/FRONT DISTANCE ARRAYS

//09/20/20 have to do this for parallel finding to go the right way

Serial.println(F("Initializing Left, Right, Front Distance Arrays..."));

#ifndef NO_PINGS

//03/30/21 moved FrontDistArray init ahead of left/right dist init to prevent inadvertent 'stuck' detection

Serial.println(F("Initializing Front Distance Array"));

InitFrontDistArray(); //08/12/20 code extracted to fcn so can call elsewhere

//Serial.println(F("Updating Left\tRight Distance Arrays"));

//for (size_t i = 0; i < LR_DIST_ARRAY_SIZE; i++)

//{

// delay(100); //ensure enough time for ISR to update distances

// mySerial.printf("%d\t%d\n", Lidar_LeftCenter, Lidar_RightCenter);

// UpdateLRDistanceArrays(Lidar_LeftCenter, Lidar_RightCenter);

//}

//Serial.println(F("Updating Rear Distance Arrays"));

//InitRearDistArray();

//mySerial.printf("Initial rear prev_mean, prev_var = %2.2f, %2.2f\n",

// Rear_Dist_PrevMean, Rear_Dist_PrevVar);

#else

Serial.println(F("Distance Sensors Disabled"));

#endif // NO_PINGS

#pragma endregion L/R/FRONT DISTANCE ARRAYS

#pragma region WALL_TRACK_TEST

mySerial.printf("End of test - Stopping!\n");

//while (true)

//{

// CheckForUserInput();

//}

StopBothMotors();

Serial.println(F("Setting Kp value"));

const int bufflen = 80;

char buff[bufflen];

memset(buff, 0, bufflen);

float OffsetCm;

float Kp, Ki, Kd;

const char s[2] = ",";

char* token;

//consume CR/LF chars

while (Serial.available() > 0)

{

int byte = Serial.read();

mySerial.printf("consumed %d\n", byte);

}

while (!Serial.available())

{

}

Serial.readBytes(buff, bufflen);

mySerial.printf("%s\n", buff);

/* extract Kp */

token = strtok(buff, s);

Kp = atof(token);

/* extract Ki */

token = strtok(NULL, s);

Ki = atof(token);

/* extract Kd */

token = strtok(NULL, s);

Kd = atof(token);

/* extract Offset in cm */

token = strtok(NULL, s);

OffsetCm = atof(token);

//mySerial.printf("Kp,Ki,Kd,OffsetCm = %2.2f, %2.2f, %2.2f, %2.2f\n",

// Kp, Ki, Kd, OffsetCm);

//TrackLeftWallOffset(Kp, Ki, Kd, OffsetCm);

TrackRightWallOffset(Kp, Ki, Kd, OffsetCm);

//mySerial.printf("Rdist\tCdist\tFdist\tsteer\toffang\n");

//while (true)

//{

// //double offangdeg = GetSteeringAngle(Lidar_LeftCenter / 10, LeftSteeringVal);

// double offangdeg = GetSteeringAngle(LeftSteeringVal); //06/25/21 chg to mm vs cm

// mySerial.printf("%d\t%d\t%d\t%2.4f\t%2.2f\n", Lidar_LeftRear, Lidar_LeftCenter, Lidar_LeftFront, LeftSteeringVal, offangdeg);

// delay(1000);

//}

#pragma endregion WALL_TRACK_TEST

}

void loop()

{

}

void CheckForUserInput()

{

const int bufflen = 80;

char buff[bufflen];

memset(buff, 0, bufflen);

float OffsetCm;

float Kp, Ki, Kd;

const char s[2] = ",";

char* token;

if (Serial.available() > 0)

{

// read the incoming byte:

int incomingByte = Serial.read();

// say what you got:

//Serial.print("I received: ");

//Serial.println(incomingByte, HEX); //chg to HEX 02/18/20

//02/18/20 experiment with multiple commands

switch (incomingByte)

{

case 0x43: //ASCII 'C'

case 0x63: //ASCII 'c'

#pragma region MANUALCONTROL

//enter infinite loop for direct remote control

Serial.println(F("ENTERING COMMAND MODE:"));

Serial.println(F("0 = 180 deg CCW Turn"));

Serial.println(F("1 = 180 deg CW Turn"));

Serial.println(F("A = Back to Auto Mode"));

Serial.println(F("S = Stop"));

Serial.println(F("F = Forward"));

Serial.println(F("R = Reverse"));

Serial.println(F(""));

Serial.println(F(" Faster"));

Serial.println(F("\t8"));

Serial.println(F("Left 4\t5 6 Right"));

Serial.println(F("\t2"));

Serial.println(F(" Slower"));

StopBothMotors();

int speed = 0;

bool bAutoMode = false;

while (!bAutoMode)

{

if (Serial.available() > 0)

{

// read the incoming byte:

int incomingByte = Serial.read();

//mySerial.printf("Got %x\n", incomingByte);

switch (incomingByte)

{

case 0x54: //ASCII 'T'

case 0x74: //ASCII 't'

Serial.println(F("Toggle TIMER5 Enable/Disable"));

if (TIMSK5 == 0)

{

Serial.println(F("Enable TIMER5"));

//TIMSK5 |= OCIE5A;

TIMSK5 |= (1 << OCIE5A);// enable timer compare interrupt

mySerial.printf("TIMSK5 = %x\n", TIMSK5);

}

else

{

Serial.println(F("Disable TIMER5"));

TIMSK5 = 0;

mySerial.printf("TIMSK5 = %x\n", TIMSK5);

}

break;

case 0x44: //ASCII 'D'

case 0x64: //ASCII 'd'

Serial.println(F("Display left/right distances"));

if (TIMSK5 == 0)

{

Serial.println(F("Enable TIMER5"));

//TIMSK5 |= OCIE5A;

TIMSK5 |= (1 << OCIE5A);// enable timer compare interrupt

mySerial.printf("TIMSK5 = %x\n", TIMSK5);

}

mySerial.printf("Msec\tLF\tLC\tLR\tRF\tRC\tRR\n");

while (true)

{

if (bTimeForNavUpdate)

{

bTimeForNavUpdate = false;

mySerial.printf("%lu\t%d\t%d\t%d\t%d\t%d\t%d\n", millis(),

Lidar_LeftFront, Lidar_LeftCenter, Lidar_LeftRear, Lidar_RightFront, Lidar_RightCenter, Lidar_RightRear);

}

break;

case 0x30: //Dec '0'

Serial.println(F("CCW 180 deg Turn"));

//RollingTurn(true, bIsForwardDir, 180);

//SpinTurn(true, 180, 45);

SpinTurn(true, 180, 90);

MoveAhead(speed, speed);

break;

case 0x31: //Dec '1'

Serial.println(F("CW 180 deg Turn"));

//RollingTurn(false, bIsForwardDir, 180);

SpinTurn(false, 180, 45);

//MoveAhead(speed, speed);

break;

case 0x34: //Turn left 10 deg

Serial.println(F("CCW 10 deg Turn"));

//MoveAhead(speed, speed);

//RollingTurn(true, bIsForwardDir, 10);

SpinTurn(true, 10, 30);

//SpinTurn(true, 30, 30);

//added 05/03/20

if (bIsForwardDir)

{

MoveAhead(speed, speed);

}

else

{

MoveReverse(speed, speed);

}

break;

case 0x36: //Turn right 10 deg'

mySerial.print("CW 10 deg Turn\n");

MoveAhead(speed, speed);

//RollingTurn(false, bIsForwardDir, 10);

SpinTurn(false, 10, 30);

//SpinTurn(false, 45, 30);

//added 05/03/20

if (bIsForwardDir)

{

MoveAhead(speed, speed);

}

else

{

MoveReverse(speed, speed);

}

break;

case 0x38: //Speed up

speed += 50;

speed = (speed >= MOTOR_SPEED_MAX) ? MOTOR_SPEED_MAX : speed;

mySerial.printf("Speeding up: speed now %d\n", speed);

if (bIsForwardDir)

{

MoveAhead(speed, speed);

}

else

{

MoveReverse(speed, speed);

}

break;

case 0x32: //Slow down

speed -= 50;

speed = (speed < 0) ? 0 : speed;

mySerial.printf("Slowing down: speed now %d\n", speed);

if (bIsForwardDir)

{

MoveAhead(speed, speed);

}

else

{

MoveReverse(speed, speed);

}

break;

case 0x35: //05/07/20 changed to use '5' vs 'S'

Serial.println(F("Stopping Motors!"));

StopBothMotors();

speed = 0;

break;

case 0x41: //ASCII 'A'

case 0x61: //ASCII 'a'

StopBothMotors();

Serial.println(F("Re-entering AUTO mode"));

bAutoMode = true;

break;

case 0x52: //ASCII 'R'

case 0x72: //ASCII 'r'

Serial.println(F("Setting both motors to reverse"));

bIsForwardDir = false;

MoveReverse(speed, speed);

break;

case 0x46: //ASCII 'F'

case 0x66: //ASCII 'f'

Serial.println(F("Setting both motors to forward"));

bIsForwardDir = true;

MoveAhead(speed, speed);

#pragma endregion MANUALCONTROL

break;

#pragma region WALL OFFSET TRACKING CASES

//left side wall tracking

case 0x4C: //ASCII 'L'

case 0x6C: //ASCII 'l'

StopBothMotors();

Serial.println(F("Setting Kp value"));

//consume CR/LF chars

while (Serial.available() > 0)

{

int byte = Serial.read();

mySerial.printf("consumed %d\n", byte);

}

while (!Serial.available())

{

}

Serial.readBytes(buff, bufflen);

mySerial.printf("%s\n", buff);

/* extract Kp */

token = strtok(buff, s);

Kp = atof(token);

/* extract Ki */

token = strtok(NULL, s);

Ki = atof(token);

/* extract Kd */

token = strtok(NULL, s);

Kd = atof(token);

/* extract Offset in cm */

token = strtok(NULL, s);

OffsetCm = atof(token);

mySerial.printf("Kp,Ki,Kd,OffsetCm = %2.2f, %2.2f, %2.2f, %2.2f\n",

Kp, Ki, Kd, OffsetCm);

TrackLeftWallOffset(Kp, Ki, Kd, OffsetCm);

break;

case 0x4D: //ASCII 'M'

case 0x6D: //ASCII 'm'

StopBothMotors();

Serial.println(F("Setting Kp value"));

//consume CR/LF chars

while (Serial.available() > 0)

{

int byte = Serial.read();

mySerial.printf("consumed %d\n", byte);

}

while (!Serial.available())

{

}

Serial.readBytes(buff, bufflen);

mySerial.printf("%s\n", buff);

/* extract Kp */

token = strtok(buff, s);

Kp = atof(token);

/* extract Ki */

token = strtok(NULL, s);

Ki = atof(token);

/* extract Kd */

token = strtok(NULL, s);

Kd = atof(token);

/* extract Offset in cm */

token = strtok(NULL, s);

OffsetCm = atof(token);

mySerial.printf("Kp,Ki,Kd,OffsetCm = %2.2f, %2.2f, %2.2f, %2.2f\n",

Kp, Ki, Kd, OffsetCm);

TrackRightWallOffset(Kp, Ki, Kd, OffsetCm);

break;

#pragma endregion WALL OFFSET TRACKING CASES

Default:

Serial.println(F("In Default Case: Stopping Motors!"));

MoveAhead(0, 0);

while (true)

{

}

void TrackLeftWallOffset(double kp, double ki, double kd, double offsetCm)

{

//Notes:

// 06/21/21 modified to do a turn, then straight, then track 0 steer val

elapsedMillis sinceLastComputeTime = 0;

double lastError = 0;

double lastInput = 0;

double lastIval = 0;

double lastDerror = 0;

bool bFirstTime = true;

double spinRateDPS = 45;

GetRequestedVL53l0xValues(VL53L0X_LEFT); //update LeftSteeringVal

mySerial.printf("Kp/Ki/Kd = %2.2f\t%2.2f\t%2.2f\n", kp, ki, kd);

//06/21/21 modified to do a turn, then straight, then track 0 steer val

double cutAngleDeg = WALL_OFFSET_TGTDIST_CM - (int)(Lidar_LeftCenter / 10.f);//positive inside, negative outside desired offset

//07/05/21 implement 15deg min cut angle

if (cutAngleDeg < 0 && abs(cutAngleDeg) < 15)

{

cutAngleDeg = -15;

}

else if (cutAngleDeg > 0 && cutAngleDeg < 15 )

{

cutAngleDeg = 15;

}

double SteerAngleDeg = GetSteeringAngle(LeftSteeringVal);

mySerial.printf("R/C/F dists = %d\t%d\t%d Steerval = %2.3f, SteerAngle = %2.2f, CutAngle = %2.2f\n",

Lidar_LeftRear, Lidar_LeftCenter, Lidar_LeftFront, LeftSteeringVal, SteerAngleDeg, cutAngleDeg);

double adjCutAngleDeg = 0;

uint16_t fudgeFactorMM = 0; //07/05/21 added so can change for inside vs outside starting condx

if (cutAngleDeg > 0) //robot inside desired offset distance

{

if (SteerAngleDeg > cutAngleDeg) // --> SteerAngleDeg also > 0

{

mySerial.printf("if (SteerAngleDeg > cutAngleDeg)\n");

SpinTurn(true, SteerAngleDeg - cutAngleDeg, spinRateDPS); //

}

else if (SteerAngleDeg < cutAngleDeg)// --> SteerAngleDeg could be < 0

{

if (SteerAngleDeg <= 0 ) //cutAngleDeg > 0, SteerAngleDeg <= 0

{

mySerial.printf("if (SteerAngleDeg <= 0)\n");

SpinTurn(false,cutAngleDeg - SteerAngleDeg, spinRateDPS); //null out SteerAngleDeg & then turn addnl cutAngleDeg

}

else //SteerAngleDeg < cutAngleDeg but still > 0

{

mySerial.printf("else\n");

SpinTurn(false,cutAngleDeg - SteerAngleDeg, spinRateDPS); //turn diff between SteerAngleDeg & cutAngleDeg

}

fudgeFactorMM = -100; //07/05/21 don't need fudge factor for inside start condx

}

else // cutAngleDeg < 0 --> robot outside desired offset distance

{

if (SteerAngleDeg > cutAngleDeg) // --> SteerAngleDeg may also be > 0

{

mySerial.printf("if (SteerAngleDeg > cutAngleDeg)\n");

SpinTurn(true, SteerAngleDeg - cutAngleDeg, spinRateDPS); //

}

else if (SteerAngleDeg < cutAngleDeg)// --> SteerAngleDeg must also be < 0

{

if (SteerAngleDeg <= 0) //cutAngleDeg > 0, SteerAngleDeg <= 0

{

mySerial.printf("if (SteerAngleDeg <= 0)\n");

SpinTurn(false, cutAngleDeg - SteerAngleDeg, spinRateDPS); //null out SteerAngleDeg & then turn addnl cutAngleDeg

}

else //SteerAngleDeg < cutAngleDeg but still > 0

{

mySerial.printf("else\n");

SpinTurn(false, cutAngleDeg - SteerAngleDeg, spinRateDPS); //turn diff between SteerAngleDeg & cutAngleDeg

}

fudgeFactorMM = 100; //07/05/21 need fudge factor for outside start condx

}

delay(1000);

//adjust so offset capture occurs at correct perpendicular offset

//double adjfactor = cos(PI * avgAppAngle / 180.f);

double adjfactor = cos(PI * cutAngleDeg / 180.f);

int adjOffsetMM = (int)(10 * (double)WALL_OFFSET_TGTDIST_CM / adjfactor);

//adjOffsetMM += 100; //fudge factor for distance measurements lagging behind robot's travel.

adjOffsetMM += fudgeFactorMM; //fudge factor for distance measurements lagging behind robot's travel.

//mySerial.printf("at approach start: steerval = %2.3f, adj cut angle = %2.2f, adjfactor = %2.3f, tgt dist = %d\n", avgSteerVal, avgAppAngle, adjfactor, adjOffsetMM);

mySerial.printf("at approach start: cut angle = %2.3f, adjfactor = %2.3f, tgt dist = %d\n", cutAngleDeg, adjfactor, adjOffsetMM);

//long int prev_res = Lidar_LeftFront - 10 * WALL_OFFSET_TGTDIST_CM; //neg for inside going out, pos for outside going in

long int prev_res = Lidar_LeftFront - adjOffsetMM; //neg for inside going out, pos for outside going in

long int res = prev_res;

mySerial.printf("At start - prev_res = %ld\n", prev_res);

mySerial.printf("Msec\tLFront\tLCtr\tLRear\tFront\tRear\tRes\tP_res\n");

//TIMSK5 = 0; //turn off TIMER5 interrupts

while (prev_res * res > 0) //sign change makes this < 0

{

prev_res = res;

MoveAhead(MOTOR_SPEED_QTR, MOTOR_SPEED_QTR);

while (!bTimeForNavUpdate)

{

}

bTimeForNavUpdate = false;

frontdistval = GetFrontDistCm();

res = Lidar_LeftFront - adjOffsetMM; //06/29/21 now adj for slant dist vs perp dist

mySerial.printf("%lu\t%d\t%d\t%d\t%d\t%d\t%ld\t%ld\n",

millis(),

Lidar_LeftFront, Lidar_LeftCenter, Lidar_LeftRear, frontdistval, Lidar_Rear, res, prev_res);

CheckForUserInput();

}

//now turn back the same (unadjusted) amount

mySerial.printf("At end - prev_res*res = %ld\n", prev_res*res);

mySerial.printf("correct back to parallel\n");

SpinTurn(!(cutAngleDeg < 0), abs(cutAngleDeg), spinRateDPS); //have to use abs() here, as cutAngleDeg can be neg

//sinceLastComputeTime = 0;

WallTrackSetPoint = 0; //moved here 6/22/21

//TIMSK5 |= (1 << OCIE5A);// enable timer compare interrupt

mySerial.printf("Msec\tFdir\tCdir\tRdir\tSteer\tSet\terror\tIval\tKp*err\tKi*Ival\tKd*Din\tOutput\tLspd\tRspd\n");

while (true)

{

CheckForUserInput(); //this is a bit recursive, but should still work (I hope)

//now using TIMER5 100 mSec interrupt for timing

if (bTimeForNavUpdate)

{

//sinceLastComputeTime -= WALL_TRACK_UPDATE_INTERVAL_MSEC;

bTimeForNavUpdate = false;

//GetRequestedVL53l0xValues(VL53L0X_LEFT); //now done in TIMER5 ISR

//have to weight value by both angle and wall offset

WallTrackSteerVal = LeftSteeringVal + (Lidar_LeftCenter - 10 * WALL_OFFSET_TGTDIST_CM) / 1000.f;

//update motor speeds, skipping bad values

if (!isnan(WallTrackSteerVal))

{

//10/12/20 now this executes every time, with interval controlled by timer ISR

PIDCalcs(WallTrackSteerVal, WallTrackSetPoint, TIMER5_INTERVAL_MSEC, lastError, lastInput, lastIval, lastDerror,

kp, ki, kd, WallTrackOutput);

int speed = 0;

int leftspeednum = MOTOR_SPEED_QTR + WallTrackOutput;

int rightspeednum = MOTOR_SPEED_QTR - WallTrackOutput;

rightspeednum = (rightspeednum <= MOTOR_SPEED_FULL) ? rightspeednum : MOTOR_SPEED_FULL;

rightspeednum = (rightspeednum > 0) ? rightspeednum : 0;

leftspeednum = (leftspeednum <= MOTOR_SPEED_FULL) ? leftspeednum : MOTOR_SPEED_FULL;

leftspeednum = (leftspeednum > 0) ? leftspeednum : 0;

MoveAhead(leftspeednum, rightspeednum);

mySerial.printf("%lu \t%d\t%d\t%d \t%2.2f\t%2.2f\t%2.2f\t%2.2f \t%2.2f\t%2.2f\t%2.2f \t%2.2f\t%d\t%d\n",

millis(),

Lidar_LeftFront, Lidar_LeftCenter, Lidar_LeftRear,

WallTrackSteerVal, WallTrackSetPoint, lastError, lastIval,

kp * lastError, ki * lastIval, kd * lastDerror,

WallTrackOutput, leftspeednum, rightspeednum);

}

void TrackRightWallOffset(double kp, double ki, double kd, double offsetCm)

{

//Notes:

// 06/21/21 modified to do a turn, then straight, then track 0 steer val

elapsedMillis sinceLastComputeTime = 0;

double lastError = 0;

double lastInput = 0;

double lastIval = 0;

double lastDerror = 0;

bool bFirstTime = true;

double spinRateDPS = 45;

GetRequestedVL53l0xValues(VL53L0X_RIGHT); //update RightSteeringVal = (Front - Rear)/100

mySerial.printf("Kp/Ki/Kd = %2.2f\t%2.2f\t%2.2f\n", kp, ki, kd);

//06/21/21 modified to do a turn, then straight, then track 0 steer val

double cutAngleDeg = WALL_OFFSET_TGTDIST_CM - (int)(Lidar_RightCenter / 10.f);//positive inside, negative outside desired offset

//07/05/21 implement 15deg min cut angle

if (cutAngleDeg < 0 && abs(cutAngleDeg) < 15)

{

cutAngleDeg = -15;

}

else if (cutAngleDeg > 0 && cutAngleDeg < 15)

{

cutAngleDeg = 15;

}

double SteerAngleDeg = GetSteeringAngle(RightSteeringVal);

mySerial.printf("R/C/F dists = %d\t%d\t%d Steerval = %2.3f, SteerAngle = %2.2f, CutAngle = %2.2f\n",

Lidar_RightRear, Lidar_RightCenter, Lidar_RightFront, RightSteeringVal, SteerAngleDeg, cutAngleDeg);

double adjCutAngleDeg = 0;

uint16_t fudgeFactorMM = 0; //07/05/21 added so can change for inside vs outside starting condx

if (cutAngleDeg > 0) //robot inside desired offset distance

{

if (SteerAngleDeg > cutAngleDeg) // --> SteerAngleDeg also > 0 (pointing away from wall)

{

mySerial.printf("if (SteerAngleDeg > cutAngleDeg)\n");

SpinTurn(false, SteerAngleDeg - cutAngleDeg, spinRateDPS); //

}

else if (SteerAngleDeg < cutAngleDeg)// --> SteerAngleDeg could be < 0

{

if (SteerAngleDeg <= 0) //cutAngleDeg > 0, SteerAngleDeg <= 0

{

mySerial.printf("if (SteerAngleDeg <= 0)\n");

//SpinTurn(false, cutAngleDeg - SteerAngleDeg, spinRateDPS); //null out SteerAngleDeg & then turn addnl cutAngleDeg

SpinTurn(true, cutAngleDeg - SteerAngleDeg, spinRateDPS); //null out SteerAngleDeg & then turn addnl cutAngleDeg

}

else //SteerAngleDeg < cutAngleDeg but still > 0

{

mySerial.printf("else\n");

//SpinTurn(false, cutAngleDeg - SteerAngleDeg, spinRateDPS); //turn diff between SteerAngleDeg & cutAngleDeg

SpinTurn(true, cutAngleDeg - SteerAngleDeg, spinRateDPS); //turn diff between SteerAngleDeg & cutAngleDeg

}

fudgeFactorMM = -100; //07/05/21 don't need fudge factor for inside start condx

}

else // cutAngleDeg < 0 --> robot outside desired offset distance

{

if (SteerAngleDeg > cutAngleDeg) // --> SteerAngleDeg may also be > 0

{

mySerial.printf("if (SteerAngleDeg > cutAngleDeg)\n");

SpinTurn(false, SteerAngleDeg - cutAngleDeg, spinRateDPS); //

}

else if (SteerAngleDeg < cutAngleDeg)// --> SteerAngleDeg must also be < 0

{

if (SteerAngleDeg <= 0) //cutAngleDeg > 0, SteerAngleDeg <= 0

{

mySerial.printf("if (SteerAngleDeg <= 0)\n");

//SpinTurn(false, cutAngleDeg - SteerAngleDeg, spinRateDPS); //null out SteerAngleDeg & then turn addnl cutAngleDeg

SpinTurn(true, cutAngleDeg - SteerAngleDeg, spinRateDPS); //null out SteerAngleDeg & then turn addnl cutAngleDeg

}

else //SteerAngleDeg < cutAngleDeg but still > 0

{

mySerial.printf("else\n");

//SpinTurn(false, cutAngleDeg - SteerAngleDeg, spinRateDPS); //turn diff between SteerAngleDeg & cutAngleDeg

SpinTurn(true, cutAngleDeg - SteerAngleDeg, spinRateDPS); //turn diff between SteerAngleDeg & cutAngleDeg

}

fudgeFactorMM = 100; //07/05/21 need fudge factor for outside start condx

}

//DEBUG!!

//mySerial.printf("Msec\tFront\tCtr\ttRear\tSteer\tAngle\n");

//double sumOfSteerVals = 0;

//for (size_t i = 0; i < 10; i++)

//{

// while (!bTimeForNavUpdate)

// {

// }

// bTimeForNavUpdate = false;

// //GetRequestedVL53l0xValues(VL53L0X_LEFT); //refresh steering value

// mySerial.printf("%lu\t%d\t%d\t%d\t%2.3f\t%2.2f\n",millis(),

// Lidar_RightFront, Lidar_RightCenter, Lidar_RightRear, RightSteeringVal, GetSteeringAngle(RightSteeringVal));

// sumOfSteerVals += RightSteeringVal;

// //delay(100);

//}

//double avgSteerVal = sumOfSteerVals / 10.f;

//double avgAppAngle = GetSteeringAngle(avgSteerVal);

//mySerial.printf("avg steerval = %2.3f, avg angle = %2.3f\n", avgSteerVal, avgAppAngle);

//DEBUG!!

delay(1000);

//adjust so offset capture occurs at correct perpendicular offset

//double adjfactor = cos(PI * avgAppAngle / 180.f);

double adjfactor = cos(PI * cutAngleDeg / 180.f);

int adjOffsetMM = (int)(10 * (double)WALL_OFFSET_TGTDIST_CM / adjfactor);

//adjOffsetMM += 100; //fudge factor for distance measurements lagging behind robot's travel.

adjOffsetMM += fudgeFactorMM; //fudge factor for distance measurements lagging behind robot's travel.

//mySerial.printf("at approach start: steerval = %2.3f, adj cut angle = %2.2f, adjfactor = %2.3f, tgt dist = %d\n", avgSteerVal, avgAppAngle, adjfactor, adjOffsetMM);

mySerial.printf("at approach start: cut angle = %2.3f, adjfactor = %2.3f, tgt dist = %d\n", cutAngleDeg, adjfactor, adjOffsetMM);

//long int prev_res = Lidar_RightFront - 10 * WALL_OFFSET_TGTDIST_CM; //neg for inside going out, pos for outside going in

long int prev_res = Lidar_RightFront - adjOffsetMM; //neg for inside going out, pos for outside going in

long int res = prev_res;

mySerial.printf("At start - prev_res = %ld\n", prev_res);

mySerial.printf("Msec\tLFront\tLCtr\tLRear\tFront\tRear\tRes\tP_res\n");

//TIMSK5 = 0; //turn off TIMER5 interrupts

while (prev_res * res > 0) //sign change makes this < 0

{

prev_res = res;

MoveAhead(MOTOR_SPEED_QTR, MOTOR_SPEED_QTR);

while (!bTimeForNavUpdate)

{

}

bTimeForNavUpdate = false;

frontdistval = GetFrontDistCm();

res = Lidar_RightFront - adjOffsetMM; //06/29/21 now adj for slant dist vs perp dist

mySerial.printf("%lu\t%d\t%d\t%d\t%d\t%d\t%ld\t%ld\n",

millis(),

Lidar_RightFront, Lidar_RightCenter, Lidar_RightRear, frontdistval, Lidar_Rear, res, prev_res);

CheckForUserInput();

}

//now turn back the same (unadjusted) amount

mySerial.printf("At end - prev_res*res = %ld\n", prev_res * res);

mySerial.printf("correct back to parallel\n");

//SpinTurn(!(cutAngleDeg < 0), abs(cutAngleDeg), spinRateDPS); //have to use abs() here, as cutAngleDeg can be neg

SpinTurn((cutAngleDeg < 0), abs(cutAngleDeg), spinRateDPS); //have to use abs() here, as cutAngleDeg can be neg

//sinceLastComputeTime = 0;

WallTrackSetPoint = 0; //moved here 6/22/21

//TIMSK5 |= (1 << OCIE5A);// enable timer compare interrupt

mySerial.printf("Msec\tFdir\tCdir\tRdir\tSteer\tSet\terror\tIval\tKp*err\tKi*Ival\tKd*Din\tOutput\tLspd\tRspd\n");

while (true)

{

CheckForUserInput(); //this is a bit recursive, but should still work (I hope)

//now using TIMER5 100 mSec interrupt for timing

if (bTimeForNavUpdate)

{

//sinceLastComputeTime -= WALL_TRACK_UPDATE_INTERVAL_MSEC;

bTimeForNavUpdate = false;

//GetRequestedVL53l0xValues(VL53L0X_LEFT); //now done in TIMER5 ISR

//have to weight value by both angle and wall offset

WallTrackSteerVal = RightSteeringVal + (Lidar_RightCenter - 10 * WALL_OFFSET_TGTDIST_CM) / 1000.f;

//update motor speeds, skipping bad values

if (!isnan(WallTrackSteerVal))

{

//10/12/20 now this executes every time, with interval controlled by timer ISR

//PIDCalcs(WallTrackSteerVal, WallTrackSetPoint, TIMER5_INTERVAL_MSEC, lastError, lastInput, lastIval, lastDerror,

// kp, ki, kd, WallTrackOutput);

PIDCalcs(WallTrackSteerVal, WallTrackSetPoint, TIMER5_INTERVAL_MSEC, lastError, lastInput, lastIval, lastDerror,

kp, ki, kd, WallTrackOutput);

int speed = 0;

//07/05/21 reverse signs for right side tracking

//int leftspeednum = MOTOR_SPEED_QTR + WallTrackOutput;

//int rightspeednum = MOTOR_SPEED_QTR - WallTrackOutput;

int leftspeednum = MOTOR_SPEED_QTR - WallTrackOutput;

int rightspeednum = MOTOR_SPEED_QTR + WallTrackOutput;

rightspeednum = (rightspeednum <= MOTOR_SPEED_FULL) ? rightspeednum : MOTOR_SPEED_FULL;

rightspeednum = (rightspeednum > 0) ? rightspeednum : 0;

leftspeednum = (leftspeednum <= MOTOR_SPEED_FULL) ? leftspeednum : MOTOR_SPEED_FULL;

leftspeednum = (leftspeednum > 0) ? leftspeednum : 0;

MoveAhead(leftspeednum, rightspeednum);

//mySerial.printf("%lu \t%d\t%d\t%d \t%2.2f\t%2.2f\t%2.2f\t%2.2f \t%2.2f\t%2.2f\t%2.2f \t%2.2f\t%d\t%d\n",

// millis(),

// Lidar_RightFront, Lidar_RightCenter, Lidar_RightRear,

// WallTrackSteerVal, WallTrackSetPoint, lastError, lastIval,

// kp * lastError, ki * lastIval, kd * lastDerror,

// WallTrackOutput, leftspeednum, rightspeednum);

mySerial.printf("%lu \t%d\t%d\t%d \t%2.2f\t%2.2f\t%2.2f\t%2.2f \t%2.2f\t%2.2f\t%2.2f \t%2.2f\t%d\t%d\n",

millis(),

Lidar_RightFront, Lidar_RightCenter, Lidar_RightRear,

-WallTrackSteerVal, WallTrackSetPoint, lastError, lastIval,

kp * lastError, ki * lastIval, kd * lastDerror,

WallTrackOutput, leftspeednum, rightspeednum);

}

#pragma region MOTOR SUPPORT

//09/08/20 modified for DRV8871 motor driver

void MoveReverse(int leftspeednum, int rightspeednum)

{

//Purpose: Move in reverse direction continuously - companion to MoveAhead()

//ProvEnA_Pinnce: G. Frank Paynter 09/08/18

//Inputs:

// leftspeednum = integer denoting speed (0=stop, 255 = full speed)

// rightspeednum = integer denoting speed (0=stop, 255 = full speed)

//Outputs: both drive Motors energized with the specified speed

//Plan:

// Step 1: Set reverse direction for both wheels

// Step 2: Run both Motors at specified speeds

//Notes:

// 01/22/20 now using Adafruit DRV8871 drivers

//Step 1: Set reverse direction and speed for both wheels

SetLeftMotorDirAndSpeed(REV_DIR, leftspeednum);

SetRightMotorDirAndSpeed(REV_DIR, rightspeednum);

}

//09/08/20 modified for DRV8871 motor driver

void MoveAhead(int leftspeednum, int rightspeednum)

{

//Purpose: Move ahead continuously

//ProvEnA_Pinnce: G. Frank Paynter and Danny Frank 01/24/2014

//Inputs:

// leftspeednum = integer denoting speed (0=stop, 255 = full speed)

// rightspeednum = integer denoting speed (0=stop, 255 = full speed)

//Outputs: both drive Motors energized with the specified speed

//Plan:

// Step 1: Set forward direction for both wheels

// Step 2: Run both Motors at specified speeds

//Notes:

// 01/22/20 now using Adafruit DRV8871 drivers

//mySerial.printf("InMoveAhead(%d,%d)\n", leftspeednum, rightspeednum);

//Step 1: Set forward direction and speed for both wheels

SetLeftMotorDirAndSpeed(true, leftspeednum);

SetRightMotorDirAndSpeed(true, rightspeednum);

}

//09/08/10 modified for DRV8871 motor driver

void StopLeftMotors()

{

analogWrite(In1_Left, MOTOR_SPEED_OFF);

analogWrite(In2_Left, MOTOR_SPEED_OFF);

}

void StopRightMotors()

{

analogWrite(In1_Right, MOTOR_SPEED_OFF);

analogWrite(In2_Right, MOTOR_SPEED_OFF);

}

//09/08/20 added bool bisFwd param for DRV8871 motor driver

void RunBothMotors(bool bisFwd, int leftspeednum, int rightspeednum)

{

//Purpose: Run both Motors at left/rightspeednum speeds

//Inputs:

// speednum = speed value (0 = OFF, 255 = full speed)

//Outputs: Both Motors run for timesec seconds at speednum speed

//Plan:

// Step 1: Apply drive to both wheels

//Notes:

// 01/14/15 - added left/right speed offset for straightness compensation

// 01/22/15 - added code to restrict fast/slow values

// 01/24/15 - revised for continuous run - no timing

// 01/26/15 - speednum modifications moved to UpdateWallFollowmyMotorspeeds()

// 12/07/15 - chg args from &int to int

//Step 1: Apply drive to both wheels

//DEBUG!!

//mySerial.printf("In RunBothMotors(%s, %d,%d)\n", bisFwd? "FWD":"REV", leftspeednum, rightspeednum);

//DEBUG!!

SetLeftMotorDirAndSpeed(bisFwd, leftspeednum);

SetRightMotorDirAndSpeed(bisFwd, rightspeednum);

}

void RunBothMotorsBidirectional(int leftspeed, int rightspeed)

{

//Purpose: Accommodate the need for independent bidirectional wheel motion

//Inputs:

// leftspeed - integer denoting left wheel speed. Positive value is fwd, negative is rev

// rightspeed - integer denoting right wheel speed. Positive value is fwd, negative is rev

//Outputs:

// left/right wheel motors direction and speed set as appropriate

//Plan:

// Step1: Set left wheel direction and speed

// Step2: Set right wheel direction and speed

//Step1: Set left wheel direction and speed

//DEBUG!!

//mySerial.printf("In RunBothMotorsBidirectional(%d, %d)\n", leftspeed, rightspeed);

if (leftspeed < 0)

{

SetLeftMotorDirAndSpeed(false, -leftspeed); //neg value ==> reverse

}

else

{

SetLeftMotorDirAndSpeed(true, leftspeed); //pos or zero value ==> fwd

}

//Step2: Set right wheel direction and speed

if (rightspeed < 0)

{

SetRightMotorDirAndSpeed(false, -rightspeed); //neg value ==> reverse

}

else

{

SetRightMotorDirAndSpeed(true, rightspeed); //pos or zero value ==> fwd

}

//09/08/20 added bool bisFwd param for DRV8871 motor driver

void RunBothMotorsMsec(bool bisFwd, int timeMsec, int leftspeednum, int rightspeednum)

{

//Purpose: Run both Motors for timesec seconds at speednum speed

//Inputs:

// timesec = time in seconds to run the Motors

// speednum = speed value (0 = OFF, 255 = full speed)

//Outputs: Both Motors run for timesec seconds at speednum speed

//Plan:

// Step 1: Apply drive to both wheels

// Step 2: Delay timsec seconds

// Step 3: Remove drive from both wheels.

//Notes:

// 01/14/15 - added left/right speed offset for straightness compensation

// 01/22/15 - added code to restrict fast/slow values

// 11/25/15 - rev to use motor driver class object

// 09/08/20 added bool bisFwd param for DRV8871 motor driver

RunBothMotors(bisFwd, leftspeednum, rightspeednum);

//Step 2: Delay timsec seconds

delay(timeMsec);

//Step3: Stop motors added 04/12/21

StopBothMotors();

}

//11/25/15 added for symmetry ;-).

void StopBothMotors()

{

StopLeftMotors();

StopRightMotors();

}

void SetLeftMotorDirAndSpeed(bool bIsFwd, int speed)

{

//mySerial.printf("SetLeftMotorDirAndSpeed(%d,%d)\n", bIsFwd, speed);

#ifndef NO_MOTORS

if (bIsFwd)

{

digitalWrite(In1_Left, LOW);

analogWrite(In2_Left, speed);

//mySerial.printf("In TRUE block of SetLeftMotorDirAndSpeed(%s, %d)\n",

// (bIsFwd == true) ? "true" : "false", speed);

}

else

{

//mySerial.printf("In FALSE block of SetLeftMotorDirAndSpeed(%s, %d)\n",

// (bIsFwd == true) ? "true" : "false", speed);

digitalWrite(In2_Left, LOW);

analogWrite(In1_Left, speed);

}

#endif // !NO_MOTORS

}

void SetRightMotorDirAndSpeed(bool bIsFwd, int speed)

{

//mySerial.printf("In SetRightMotorDirAndSpeed(%s, %d)\n",

// (bIsFwd == true) ? "true" : "false", speed);

#ifndef NO_MOTORS

if (bIsFwd)

{

//mySerial.printf("In TRUE block of SetRighttMotorDirAndSpeed(%s, %d)\n",

// (bIsFwd == true) ? "true" : "false", speed);

digitalWrite(In1_Right, LOW);

analogWrite(In2_Right, speed);

}

else

{

//mySerial.printf("In FALSE block of SetRightMotorDirAndSpeed(%s, %d)\n",

// (bIsFwd == true) ? "true" : "false", speed);

digitalWrite(In2_Right, LOW);

analogWrite(In1_Right, speed);

}

#endif // !NO_MOTORS

}

#pragma endregion Motor Support Functions

#pragma region MPU5060 Support

float UpdateIMUHdgValDeg()

{

//Purpose: Get latest yaw (heading) value from IMU

//Inputs: None. This function should only be called after mpu.dmpPacketAvailable() returns TRUE

//Outputs:

// returns true if successful, otherwise false

// IMUHdgValDeg updated on success

//Plan:

//Step1: check for overflow and reset the FIFO if it occurs. In this case, wait for new packet

//Step2: read all available packets to get to latest data

//Step3: update IMUHdgValDeg with latest value

//Notes:

// 10/08/19 changed return type to boolean

// 10/08/19 no longer need mpuIntStatus

// 10/21/19 completely rewritten to use Homer's algorithm

// 05/05/20 changed return type to float vs bool.

bool retval = false;

int flag = GetCurrentFIFOPacket(fifoBuffer, packetSize, MAX_GETPACKET_LOOPS); //get the latest mpu packet

if (flag != 0) //0 = error exit, 1 = normal exit, 2 = recovered from an overflow

{

// display Euler angles in degrees

mpu.dmpGetQuaternion(&q, fifoBuffer);

mpu.dmpGetGravity(&gravity, &q);

mpu.dmpGetYawPitchRoll(ypr, &q, &gravity);

//compute the yaw value

IMUHdgValDeg = ypr[0] * 180 / M_PI;

retval = true;

}

//return retval;

return IMUHdgValDeg;//05/05/20 now returns updated value for use convenience

}

uint8_t GetCurrentFIFOPacket(uint8_t* data, uint8_t length, uint16_t max_loops)

{

mpu.resetFIFO();

delay(1);

//int countloop = 0;

fifoCount = mpu.getFIFOCount();

GetPacketLoopCount = 0;

//mySerial.printf("In GetCurrentFIFOPacket: before loop fifoC = %d\t", fifoCount);

while (fifoCount < packetSize && GetPacketLoopCount < max_loops)

{

GetPacketLoopCount++;

fifoCount = mpu.getFIFOCount();

delay(2);

}

//mySerial.printf("In GetCurrentFIFOPacket: after loop fifoC = %d, loop count = %d\n", fifoCount, GetPacketLoopCount);

if (GetPacketLoopCount >= max_loops)

{

return 0;

}

//if we get to here, there should be exactly one packet in the FIFO

mpu.getFIFOBytes(data, packetSize);

return 1;

}

#pragma endregion MPU5060 Support

#pragma region HDG_BASED_TURN_SUPPORT

float GetHdgMatchVal(float tgt_deg, float cur_deg)

{

//Purpose: Compute the match ratio between two compass headings

//Inputs:

// tgt_deg = float representing target heading in +/-180 range

// IMUHdgValDeg = float representing sensor yaw value in +/-180 deg range

//Outputs:

// returns result of 1 - abs(Tgt_deg - Hdg_deg)/180, all angles in 0-360 deg range

//Plan:

// Step1: convert both inputs to 0-360 deg range

// Step2: compute match ratio

//Notes:

// formula from https://gis.stackexchange.com/questions/129954/comparing-compass-bearings

//Step1: convert both inputs to 0-360 deg range

float tgthdg = (tgt_deg < 0) ? tgt_deg + 360 : tgt_deg;

float curhdg = (cur_deg < 0) ? cur_deg + 360 : cur_deg;

//Step2: compute match ratio

float match_ratio = 1 - abs(tgthdg - curhdg) / 180;

//DEBUG!!

//mySerial.printf("tgt\tcur\tmatch = %4.2f\t%4.2f\t%1.3f\n", tgthdg, curhdg, match_ratio);

//DEBUG!!

return abs(match_ratio);

}

bool SpinTurn(bool b_ccw, float numDeg, float degPersec) //04/25/21 added turn-rate arg (default = TURN_RATE_TARGET_DEGPERSEC)

{

//Purpose: Make a numDeg CW or CCW 'spin' turn

//Inputs:

// b_ccw - True if turn is to be ccw, false otherwise

// numDeg - angle to be swept out in the turn

// ROLLING_TURN_MAX_SEC_PER_DEG = const used to generate timeout proportional to turn deg

// IMUHdgValDeg = IMU heading value updated by UpdateIMUHdgValDeg() //11/02/20 now updated in ISR

// degPerSec = float value denoting desired turn rate

//Plan:

// Step1: Get current heading as starting point

// Step2: Disable TIMER5 interrupts

// Step3: Compute new target value & timeout value

// Step4: Run motors until target reached, using inline PID algorithm to control turn rate

// Step5: Re-enable TIMER5 interrupts

//Notes:

// 06/06/21 we-written to remove PID library - now uses custom 'PIDCalcs()' function

// 06/06/21 added re-try for 180.00 return from IMU - could be bad value

// 06/11/21 added code to correct dHdg errors due to 179/-179 transition & bad IMU values

// 06/12/21 cleaned up & commented out debug code

float tgt_deg;

float timeout_sec;

bool bDoneTurning = false;

bool bTimedOut = false;

bool bResult = true; //04/21/20 added so will be only one exit point

//DEBUG!!

mySerial.printf("In SpinTurn(%s, %2.2f, %2.2f)\n", b_ccw == TURNDIR_CCW ? "CCW" : "CW", numDeg, degPersec);

//DEBUG!!

//mySerial.printf("TurnRatePID started with Kp/Ki/Kd = %2.1f,%2.1f,%2.1f, SampleTime(mSec) = %d\n",

// TurnRate_Kp, TurnRate_Ki, TurnRate_Kd, TURN_RATE_UPDATE_INTERVAL_MSEC);

//no need to continue if the IMU isn't available

if (!dmpReady)

{

return false;

}

//Step1: Get current heading as starting point

//06/06/21 it is possible for IMU to return 180.00 on failure

//so try again. If it really IS 180, then

//it will eventually time out and go on

int retries = 0;

if (IMUHdgValDeg == 180.f && retries < 5)

{

//DEBUG!!

mySerial.printf("Got 180.00 exactly from IMU - retrying...\n");

//DEBUG!!

UpdateIMUHdgValDeg();

retries++;

delay(30);

}

//Step2: Compute new target value & timeout value

timeout_sec = 3 * numDeg / degPersec; //05/29/21 rev to use new turn rate parmeter

//05/17/20 limit timeout_sec to 1 sec or more

timeout_sec = (timeout_sec < 1) ? 1.f : timeout_sec;

UpdateIMUHdgValDeg();

//12/05/19 added #define back in to manage which direction increases yaw values

#ifdef MPU6050_CCW_INCREASES_YAWVAL

tgt_deg = b_ccw ? IMUHdgValDeg + numDeg : IMUHdgValDeg - numDeg;

#else

tgt_deg = b_ccw ? IMUHdgValDeg - numDeg : IMUHdgValDeg + numDeg;

#endif // MPU6050_CCW_INCREASES_YAWVAL

//correct for -180/180 transition

if (tgt_deg < -180)

{

tgt_deg += 360;

}

//07/29/19 bugfix

if (tgt_deg > 180)

{

tgt_deg -= 360;

}

//DEBUG!!

mySerial.printf("Init hdg = %4.2f deg, Turn = %4.2f deg, tgt = %4.2f deg, timeout = %4.2f sec\n\n",

IMUHdgValDeg, numDeg, tgt_deg, timeout_sec);

//DEBUG!!

double curHdgMatchVal = 0;

//09/08/18 added to bolster end-of-turn detection

float prevHdgMatchVal = 0;

float matchSlope = 0;

//Step2: Disable TIMER5 interrupts

TIMSK5 = 0; //disable timer compare interrupt

//Step3: Run motors until target reached, using PID algorithm to control turn rate

Prev_HdgDeg = IMUHdgValDeg; //06/10/21 synch Prev_HdgDeg & IMUHdgValDeg just before entering loop

//DEBUG!!

//mySerial.printf("Just before while() loop: hdg/prvhdg = %2.2f\t%2.2f\n\n", IMUHdgValDeg, Prev_HdgDeg);

//mySerial.printf("Msec\tHdg\tPrvHdg\tDhdg\trate\tSet\terror\tKp*err\tKi*err\tKd*Din\tOutput\n");

//DEBUG!!

elapsedMillis sinceLastTimeCheck = 0;

elapsedMillis sinceLastComputeTime = 0;

double lastError = 0;

double lastInput = 0;

double lastIval = 0;

double lastDerror = 0;

bool bFirstIMUHdg = true;

while (!bDoneTurning && !bTimedOut)

{

//11/06/20 now just loops between ISR hits

CheckForUserInput();

//runs every 30mSec

if (sinceLastComputeTime >= TURN_RATE_UPDATE_INTERVAL_MSEC)

{

sinceLastComputeTime -= TURN_RATE_UPDATE_INTERVAL_MSEC;

UpdateIMUHdgValDeg(); //update IMUHdgValDeg

double dHdg = IMUHdgValDeg - Prev_HdgDeg;

if (dHdg > 180)

{

dHdg -= 360;

mySerial.printf("dHdg > 180 (%2.2f - %2.2f) - subtracting 360\n", IMUHdgValDeg, Prev_HdgDeg);

}

else if (dHdg < -180)

{

dHdg += 360;

mySerial.printf("dHdg < -180 (%2.2f - %2.2f) - adding 360\n", IMUHdgValDeg, Prev_HdgDeg);

}

//watch for turn rates that are wildly off

double rate = abs(1000 * dHdg / TURN_RATE_UPDATE_INTERVAL_MSEC);

if (rate > 3 * degPersec)

{

//DEBUG!!

mySerial.printf("hdg/prevhdg/dHdg/rate = %2.2f\t%2.2f\t%2.2f\t%2.2f, excessive rate - replacing with %2.2f\n", IMUHdgValDeg, Prev_HdgDeg, dHdg, rate, degPersec);

//DEBUG!!

rate = degPersec;

}

//06/11/21 don't do calcs first time through, as Prev_HdgDeg isn't valid yet

if (bFirstIMUHdg)

{

bFirstIMUHdg = false;

Prev_HdgDeg = IMUHdgValDeg; //re-synch prev to curr hdg for next time

}

else

{

PIDCalcs(rate, degPersec, TURN_RATE_UPDATE_INTERVAL_MSEC, lastError, lastInput, lastIval, lastDerror, TurnRate_Kp, TurnRate_Ki, TurnRate_Kd, TurnRatePIDOutput);

int speed = 0;

(TurnRatePIDOutput > MOTOR_SPEED_MAX) ? speed = MOTOR_SPEED_MAX : speed = (int)TurnRatePIDOutput;

(TurnRatePIDOutput <= MOTOR_SPEED_LOW) ? speed = MOTOR_SPEED_LOW : speed = (int)TurnRatePIDOutput;

SetLeftMotorDirAndSpeed(!b_ccw, speed);

SetRightMotorDirAndSpeed(b_ccw, speed);

//check for nearly there and all the way there

curHdgMatchVal = GetHdgMatchVal(tgt_deg, IMUHdgValDeg);

matchSlope = curHdgMatchVal - prevHdgMatchVal;

prevHdgMatchVal = curHdgMatchVal;

//DEBUG!!

//mySerial.printf("%lu\t%2.2f\t%2.2f\t%2.2f\t%2.2f\t%2.2f\t%2.2f\t%2.2f\t%2.2f\t%2.2f\t%d\n",

// millis(),

// IMUHdgValDeg,

// Prev_HdgDeg,

// dHdg,

// rate,

// degPersec,

// lastError,

// TurnRate_Kp * lastError,

// TurnRate_Ki * lastIval,

// TurnRate_Kd * lastDerror,

// speed);

//DEBUG!!

Prev_HdgDeg = IMUHdgValDeg; //re-synch prev to curr hdg for next time

//look for full match

bDoneTurning = (curHdgMatchVal >= HDG_FULL_MATCH_VAL

|| (curHdgMatchVal >= HDG_MIN_MATCH_VAL && matchSlope < -0.1)); //have to use < vs <= as slope == 0 at start

}

bTimedOut = (sinceLastTimeCheck > timeout_sec * 1000);

if (bTimedOut)

{

//DEBUG!!

mySerial.printf("timed out with yaw = %3.2f, tgt = %3.2f, and match = %1.3f\n", IMUHdgValDeg, tgt_deg, curHdgMatchVal);

//DEBUG!!

bResult = false;

}

//DEBUG!!

mySerial.printf("%lu: Exiting SpinTurn() at %3.2f deg\n", millis(), IMUHdgValDeg);

//DEBUG!!

//Step4: Re-enable TIMER5 interrupts

TIMSK5 |= (1 << OCIE5A);// enable timer compare interrupt

StopBothMotors();

//delay(1000); //added 04/27/21 for debug

return bResult;

}

//bool SpinTurnToSteerVal(bool b_ccw, float tgtSteerVal, float degPersec) //04/25/21 added turn-rate arg (default = TURN_RATE_TARGET_DEGPERSEC)

//{

// //Purpose: Make a rate-controlled CW or CCW 'spin' turn to a desired steering value

// //Inputs:

// // b_ccw - True if turn is to be ccw, false otherwise

// // steerval - steering value to be met

// // ROLLING_TURN_MAX_SEC_PER_DEG = const used to generate timeout proportional to turn deg

// // IMUHdgValDeg = IMU heading value updated by UpdateIMUHdgValDeg() //11/02/20 now updated in ISR

// // degPerSec = float value denoting desired turn rate

// //Plan:

// // Step1: Get current heading as starting point

// // Step2: Disable TIMER5 interrupts

// // Step4: Run motors until target steering value reached, using inline PID algorithm to control turn rate

// // Step5: Re-enable TIMER5 interrupts

// //Notes:

// // copied from SpinTurn() and modifed to terminate on steering value

// //float tgt_deg;

// float timeout_sec;

// bool bDoneTurning = false;

// bool bTimedOut = false;

// bool bResult = true; //04/21/20 added so will be only one exit point

// ////DEBUG!!

// //mySerial.printf("In SpinTurn(%s, %2.2f, %2.2f)\n", b_ccw == TURNDIR_CCW ? "CCW" : "CW", numDeg, degPersec);

// ////DEBUG!!

// mySerial.printf("TurnRatePID started with Kp/Ki/Kd = %2.1f,%2.1f,%2.1f, SampleTime(mSec) = %d\n",

// TurnRate_Kp, TurnRate_Ki, TurnRate_Kd, TURN_RATE_UPDATE_INTERVAL_MSEC);

// //no need to continue if the IMU isn't available

// if (!dmpReady)

// {

// return false;

// }

// //Step1: Get current heading as starting point

// //06/06/21 it is possible for IMU to return 180.00 on failure

// //so try again. If it really IS 180, then

// //it will eventually time out and go on

// int retries = 0;

// if (IMUHdgValDeg == 180.f && retries < 5)

// {

// //DEBUG!!

// //mySerial.printf("Got 180.00 exactly from IMU - retrying...\n");

// //DEBUG!!

// UpdateIMUHdgValDeg();

// retries++;

// delay(30);

// }

// ////Step2: Compute new target value & timeout value

// //timeout_sec = 3 * numDeg / degPersec; //05/29/21 rev to use new turn rate parmeter

// ////05/17/20 limit timeout_sec to 1 sec or more

// //timeout_sec = (timeout_sec < 1) ? 1.f : timeout_sec;

// UpdateIMUHdgValDeg();

//// //12/05/19 added #define back in to manage which direction increases yaw values

////#ifdef MPU6050_CCW_INCREASES_YAWVAL

//// tgt_deg = b_ccw ? IMUHdgValDeg + numDeg : IMUHdgValDeg - numDeg;

////#else

//// tgt_deg = b_ccw ? IMUHdgValDeg - numDeg : IMUHdgValDeg + numDeg;

////

////#endif // MPU6050_CCW_INCREASES_YAWVAL

////

//// //correct for -180/180 transition

//// if (tgt_deg < -180)

//// {

//// tgt_deg += 360;

//// }

////

//// //07/29/19 bugfix

//// if (tgt_deg > 180)

//// {

//// tgt_deg -= 360;

//// }

// //DEBUG!!

// //mySerial.printf("Init hdg = %4.2f deg, Turn = %4.2f deg, tgt = %4.2f deg, timeout = %4.2f sec\n\n",

// // IMUHdgValDeg, numDeg, tgt_deg, timeout_sec);

// //DEBUG!!

// //float curHdgMatchVal = 0;

// ////09/08/18 added to bolster end-of-turn detection

// //float prevHdgMatchVal = 0;

// //float matchSlope = 0;

// //Step2: Disable TIMER5 interrupts

// TIMSK5 = 0; //disable timer compare interrupt

// //Step3: Run motors until target reached, using PID algorithm to control turn rate

// Prev_HdgDeg = IMUHdgValDeg; //06/10/21 synch Prev_HdgDeg & IMUHdgValDeg just before entering loop

// //DEBUG!!

// //mySerial.printf("Just before while() loop: hdg/prvhdg = %2.2f\t%2.2f\n\n", IMUHdgValDeg, Prev_HdgDeg);

// //mySerial.printf("Msec\tHdg\tPrvHdg\tDhdg\trate\tSet\terror\tKp*err\tKi*err\tKd*Din\tOutput\n");

// //DEBUG!!

// elapsedMillis sinceLastTimeCheck = 0;

// elapsedMillis sinceLastComputeTime = 0;

// double lastError = 0;

// double lastInput = 0;

// double lastIval = 0;

// double lastDerror = 0;

// bool bFirstIMUHdg = true;

// //while (!bDoneTurning && !bTimedOut)

// while (!bDoneTurning)

// {

// //11/06/20 now just loops between ISR hits

// CheckForUserInput();

// //runs every 30mSec

// if (sinceLastComputeTime >= TURN_RATE_UPDATE_INTERVAL_MSEC)

// {

// sinceLastComputeTime -= TURN_RATE_UPDATE_INTERVAL_MSEC;

// UpdateIMUHdgValDeg(); //update IMUHdgValDeg

// double dHdg = IMUHdgValDeg - Prev_HdgDeg;

// if (dHdg > 180)

// {

// dHdg -= 360;

// mySerial.printf("dHdg > 180 - subtracting 360\n");

// }

// else if (dHdg < -180)

// {

// dHdg += 360;

// mySerial.printf("dHdg < -180 - adding 360\n");

// }

// //watch for turn rates that are wildly off

// double rate = abs(1000 * dHdg / TURN_RATE_UPDATE_INTERVAL_MSEC);

// if (rate > 3 * degPersec)

// {

// //DEBUG!!

// //mySerial.printf("hdg/prevhdg/dHdg/rate = %2.2f\t%2.2f\t%2.2f\t%2.2f, excessive rate - replacing with %2.2f\n", IMUHdgValDeg, Prev_HdgDeg, dHdg, rate, degPersec);

// //DEBUG!!

// rate = degPersec;

// }

// //06/11/21 don't do calcs first time through, as Prev_HdgDeg isn't valid yet

// if (bFirstIMUHdg)

// {

// bFirstIMUHdg = false;

// Prev_HdgDeg = IMUHdgValDeg; //re-synch prev to curr hdg for next time

// }

// else

// {

// PIDCalcs(rate, degPersec, TURN_RATE_UPDATE_INTERVAL_MSEC, lastError, lastInput, lastIval, lastDerror, TurnRate_Kp, TurnRate_Ki, TurnRate_Kd, TurnRatePIDOutput);

// int speed = 0;

// (TurnRatePIDOutput > MOTOR_SPEED_MAX) ? speed = MOTOR_SPEED_MAX : speed = (int)TurnRatePIDOutput;

// (TurnRatePIDOutput <= MOTOR_SPEED_LOW) ? speed = MOTOR_SPEED_LOW : speed = (int)TurnRatePIDOutput;

// SetLeftMotorDirAndSpeed(!b_ccw, speed);

// SetRightMotorDirAndSpeed(b_ccw, speed);

// //check for nearly there and all the way there

// //curHdgMatchVal = GetHdgMatchVal(tgt_deg, IMUHdgValDeg);

// //matchSlope = curHdgMatchVal - prevHdgMatchVal;

// //prevHdgMatchVal = curHdgMatchVal;

// //DEBUG!!

// mySerial.printf("%lu\t%2.2f\t%2.2f\t%2.2f\t%2.2f\t%2.2f\t%2.2f\t%2.2f\t%2.2f\t%2.2f\t%d\n",

// millis(),

// IMUHdgValDeg,

// Prev_HdgDeg,

// dHdg,

// rate,

// degPersec,

// lastError,

// TurnRate_Kp * lastError,

// TurnRate_Ki * lastIval,

// TurnRate_Kd * lastDerror,

// speed);

// //DEBUG!!

// Prev_HdgDeg = IMUHdgValDeg; //re-synch prev to curr hdg for next time

// //look for full match

// GetRequestedVL53l0xValues(VL53L0X_ALL);

// bDoneTurning = (abs(LeftSteeringVal - tgtSteerVal) <= RATIO_TURN_MATCH_THRESHOLD);

// }

// //bTimedOut = (sinceLastTimeCheck > timeout_sec * 1000);

// //if (bTimedOut)

// //{

// // //DEBUG!!

// // //mySerial.printf("timed out with yaw = %3.2f, tgt = %3.2f, and match = %1.3f\n", IMUHdgValDeg, tgt_deg, curHdgMatchVal);

// // //DEBUG!!

// // bResult = false;

// //}

// }

// //DEBUG!!

// //mySerial.printf("%lu: Exiting SpinTurn() at %3.2f deg\n", millis(), IMUHdgValDeg);

// //DEBUG!!

////Step4: Re-enable TIMER5 interrupts

// TIMSK5 |= (1 << OCIE5A);// enable timer compare interrupt

// StopBothMotors();

// delay(1000); //added 04/27/21 for debug

// return bResult;

//}

void PIDCalcs(double input, double setpoint, uint16_t sampleTime, double& lastError, double& lastInput, double& lastIval, double& lastDerror, double Kp, double Ki, double Kd, double& output)

{

//Purpose: Encapsulate PID algorithm so can get rid of PID library. Library too cumbersome and won't synch with TIMER5 ISR

//Inputs:

// input = double denoting current input value (turn rate, speed, whatever)

// setpoint = double denoting desired setpoint in same units as input

// sampleTime = int denoting sample time to be used in calcs.

// lastError = ref to double denoting error saved from prev calc

// lastInput = ref to double denoting input saved from prev calc

// Kp/Ki/Kd = doubles denoting PID values to be used for calcs

// Output = ref to double denoting output from calc

double error = setpoint - input;

double dInput = (input - lastInput);

lastIval += (error);

double dErr = (error - lastError);

//mySerial.printf("PIDCalcs: error/dInput/lastIval/dErr/kp/ki/kd = %2.2f\t%2.2f\t%2.2f\t%2.2f\t%2.2f\t%2.2f\t%2.2f\n", error, dInput, lastIval, dErr,

// Kp,Ki,Kd);

/*Compute PID Output*/

output = Kp * error + Ki * lastIval + Kd * dErr;

/*Remember some variables for next time*/

lastError = error;

lastInput = input;

lastDerror = dErr;

}

#pragma endregion HDG_BASED_TURN_SUPPORT

bool GetRequestedVL53l0xValues(VL53L0X_REQUEST which)

{

//Purpose: Obtain VL53L0X ToF sensor data from Teensy sensor handler

//Inputs:

// which = VL53L0X_REQUEST value denoting which combination of value to retrieve

// VL53L0X_CENTERS_ONLY -> Just the left/right center sensor values

// VL53L0X_RIGHT -> All three right sensor values, in front/center/rear order

// VL53L0X_LEFT -> All three left sensor values, in front/center/rear order

// VL53L0X_ALL -> All seven sensor values, in left/right front/center/rear/rear order

// VL53L0X_REAR_ONLY -> added 10/24/20 Just the rear sensor reading

//Outputs:

// Requested sensor values, obtained via I2C from the VL53L0X sensor handler

// Returns TRUE if data retrieval successful, otherwise FALSE

//Plan:

// Step1: Send request to VL53L0X handler

// Step2: get the requested data

//Notes:

// Copied from FourWD_WallE2_V4.ino's IsIRBeamAvail() and adapted

// 08/05/20 added a VL53L0X_ALL request type

// 01/24/21 added error detection/reporting

//Step1: Send request to VL53L0X handler

//DEBUG!!

//mySerial.printf("Sending %d to slave\n", which);

//DEBUG!!

//mySerial.printf("In GetRequestedVL53l0xValues(%d)\n", (int)which);

Wire.beginTransmission(VL53L0X_I2C_SLAVE_ADDRESS);

I2C_writeAnything((uint8_t)which);

Wire.endTransmission();

//Step2: get the requested data

int readResult = 0;

int data_size = 0;

switch (which)

{

case VL53L0X_READYCHECK: //11/10/20 added to prevent bad reads during Teensy setup()

Wire.requestFrom(VL53L0X_I2C_SLAVE_ADDRESS, (int)(sizeof(bVL53L0X_TeensyReady)));

readResult = I2C_readAnything(bVL53L0X_TeensyReady);

break;

case VL53L0X_CENTERS_ONLY:

//just two data values needed here

data_size = 2 * sizeof(int);

Wire.requestFrom(VL53L0X_I2C_SLAVE_ADDRESS, (int)(2 * sizeof(Lidar_RightCenter)));

readResult = I2C_readAnything(Lidar_RightCenter);

if (readResult > 0)

{

I2C_readAnything(Lidar_LeftCenter);

}

//DEBUG!!

//mySerial.printf("VL53L0X_CENTERS_ONLY case: Got LC/RC = %d, %d\n", Lidar_LeftCenter, Lidar_RightCenter);

//DEBUG!!

break;

case VL53L0X_RIGHT:

//four data values needed here

data_size = 3 * sizeof(int) + sizeof(float);

//DEBUG!!

//mySerial.printf("data_size = %d\n", data_size);

//DEBUG!!

Wire.requestFrom(VL53L0X_I2C_SLAVE_ADDRESS, data_size);

readResult = I2C_readAnything(Lidar_RightFront);

if (readResult > 0)

{

readResult = I2C_readAnything(Lidar_RightCenter);

}

if (readResult > 0)

{

readResult = I2C_readAnything(Lidar_RightRear);

}

if (readResult > 0)

{

readResult = I2C_readAnything(RightSteeringVal);

}

//DEBUG!!

//mySerial.printf("VL53L0X_RIGHT case: Got L/C/R/S = %d, %d, %d, %3.2f\n",

// Lidar_RightFront, Lidar_RightCenter, Lidar_RightRear, ToFSteeringVal);

//DEBUG!!

break;

case VL53L0X_LEFT:

//four data values needed here

data_size = 3 * sizeof(int) + sizeof(float);

Wire.requestFrom(VL53L0X_I2C_SLAVE_ADDRESS, data_size);

readResult = I2C_readAnything(Lidar_LeftFront);

if (readResult > 0)

{

readResult = I2C_readAnything(Lidar_LeftCenter);

}

if (readResult > 0)

{

readResult = I2C_readAnything(Lidar_LeftRear);

}

if (readResult > 0)

{

readResult = I2C_readAnything(LeftSteeringVal);

}

//DEBUG!!

//mySerial.printf("VL53L0X_RIGHT case: Got L/C/R/S = %d, %d, %d, %3.2f\n",

// Lidar_LeftFront, Lidar_LeftCenter, Lidar_LeftRear, ToFSteeringVal);

//DEBUG!!

break;

case VL53L0X_ALL: //added 08/05/20, chg to VL53L0X_ALL 10/31/20

//nine data values needed here - 7 ints and 2 floats

data_size = 7 * sizeof(int) + 2 * sizeof(float); //10/31/20 added rear distance

//mySerial.printf("In VL53L0X_ALL case with data_size = %d\n", data_size);

Wire.requestFrom(VL53L0X_I2C_SLAVE_ADDRESS, data_size);

//Lidar_LeftFront

readResult = I2C_readAnything(Lidar_LeftFront);

if (readResult != sizeof(Lidar_LeftFront))

{

mySerial.printf("Error reading Lidar_LeftFront\n");

}

//Lidar_LeftCenter

readResult = I2C_readAnything(Lidar_LeftCenter);

if (readResult != sizeof(Lidar_LeftCenter))

{

mySerial.printf("Error reading Lidar_LeftCenter\n");

}

//Lidar_LeftRear

readResult = I2C_readAnything(Lidar_LeftRear);

if (readResult != sizeof(Lidar_LeftRear))

{

mySerial.printf("Error reading Lidar_LeftRear\n");

}

//LeftSteeringVal

readResult = I2C_readAnything(LeftSteeringVal);

if (readResult != sizeof(LeftSteeringVal))

{

mySerial.printf("Error reading LeftSteeringVal\n");

}

//Lidar_RightFront

readResult = I2C_readAnything(Lidar_RightFront);

if (readResult != sizeof(Lidar_RightFront))

{

mySerial.printf("Error reading Lidar_RightFront\n");

}

//Lidar_RightCenter

readResult = I2C_readAnything(Lidar_RightCenter);

if (readResult != sizeof(Lidar_RightCenter))

{

mySerial.printf("Error reading Lidar_RightCenter\n");

}

//Lidar_RightRear

readResult = I2C_readAnything(Lidar_RightRear);

if (readResult != sizeof(Lidar_RightRear))

{

mySerial.printf("Error reading Lidar_RightRear\n");

}

//RightSteeringVal

readResult = I2C_readAnything(RightSteeringVal);

if (readResult != sizeof(RightSteeringVal))

{

mySerial.printf("Error reading LeftSteeringVal\n");

}

//Lidar_Rear

readResult = I2C_readAnything(Lidar_Rear);

if (readResult != sizeof(Lidar_Rear))

{

mySerial.printf("Error reading Lidar_Rear\n");

}

//mySerial.printf("%lu: VL53l0x - %d, %d, %d, %d, %d, %d, %d\n",

// millis(),

// Lidar_LeftFront, Lidar_LeftCenter, Lidar_LeftRear,

// Lidar_RightFront, Lidar_RightCenter, Lidar_RightRear,

// Lidar_Rear);

break; //10/31/20 bugfix

case VL53L0X_REAR_ONLY:

//just ONE data value needed here

data_size = sizeof(int);

Wire.requestFrom(VL53L0X_I2C_SLAVE_ADDRESS, (int)(sizeof(Lidar_Rear)));

readResult = I2C_readAnything(Lidar_Rear);

//DEBUG!!

//mySerial.printf("VL53L0X_REAR_ONLY case: Got Rear = %d\n", Lidar_Rear);

//DEBUG!!

break;

default:

break;

}

return readResult > 0; //this is true only if all reads succeed

}

void WaitForVL53L0XTeensy()

{

bVL53L0X_TeensyReady = false;

while (!bVL53L0X_TeensyReady)

{

GetRequestedVL53l0xValues(VL53L0X_READYCHECK); //this updates bVL53L0X_TeensyReady

//mySerial.printf("%lu: got %d from VL53L0X Teensy\n", millis(), bVL53L0X_TeensyReady);

delay(100);

}

Serial.print(F("Teensy setup() finished at ")); Serial.printf("%lu mSec\n", millis());

//now try to get a VL53L0X measurement

//11/08/20 rev to loop until all distance sensors provide valid data

//mySerial.printf("Msec\tLFront\tLCtr\tLRear\tRFront\tRCtr\tRRear\tRear\n");

//mySerial.printf("%lu: %d\t%d\t%d\t%d\t%d\t%d\t%d\n",

// millis(), Lidar_LeftFront, Lidar_LeftCenter, Lidar_LeftRear,

// Lidar_RightFront, Lidar_RightCenter, Lidar_RightRear, Lidar_Rear);

while (Lidar_LeftFront <= 0 || Lidar_LeftCenter <= 0 || Lidar_LeftRear <= 0

|| Lidar_LeftFront <= 0 || Lidar_LeftCenter <= 0 || Lidar_LeftRear <= 0

|| Lidar_Rear <= 0)

{

////values updated 10 times/sec in ISR

mySerial.printf("%lu: %d\t%d\t%d\t%d\t%d\t%d\t%d\n",

millis(), Lidar_LeftFront, Lidar_LeftCenter, Lidar_LeftRear,

Lidar_RightFront, Lidar_RightCenter, Lidar_RightRear, Lidar_Rear);

delay(100);

}

mySerial.printf("VL53L0X Teensy Ready at %lu\n\n", millis());

}

double GetSteeringAngle(double steerval)

{

//Purpose: Convert a steering angle into the equivalent off-parallel orientation in degrees

//Inputs:

// steerval = double value denoting current steering value

// Notes:

// 06/27/21 now steering_val/off_angle slope is a constant 0.0175

const double slopeval = 0.0175;

double offparalleldeg = steerval / slopeval; //e.g. for steerval = -0.187 @ 10cm offset, returns +21deg

//mySerial.printf("GetSteeringAngle(%d, %2.4f): slopeval = %2.4f, res %2.2f\n", ctrdist_cm, steerval, slopeval, offparalleldeg);

return offparalleldeg;

}

//11/05/15 added to get LIDAR measurement

int GetFrontDistCm()

{

//Notes:

// 12/05/15 chg to MODE line vs I2C

// 01/06/16 rev to return avg of prev distances on error

#ifndef NO_LIDAR

unsigned long pulse_width;

int LIDARdistCm;

pulse_width = pulseIn(LIDAR_MODE_PIN, HIGH); // Count how long the pulse is high in microseconds

LIDARdistCm = pulse_width / 10; // 10usec = 1 cm of distance for LIDAR-Lite

//chk for erroneous reading

if (LIDARdistCm == 0)

{

//replace with average of last three readings from aFrontDist

int avgdist = GetAvgFrontDistCm();

mySerial.printf("%lu: Error in GetFrontDistCm() - %d replaced with %d\n", millis(), LIDARdistCm, avgdist);

LIDARdistCm = avgdist;

}

//04/30/17 added limit detection/correction

LIDARdistCm = (LIDARdistCm > 0) ? LIDARdistCm : MAX_FRONT_DISTANCE_CM;

return LIDARdistCm;

#else

return 10; //safe number, I hope

#endif

}

//04/25/21 rewritten to use aFrontDist[] values

float GetAvgFrontDistCm()

{

int avgdist = 0;

for (int i = 0; i < FRONT_DIST_AVG_WINDOW_SIZE; i++)

{

//DEBUG!!

//mySerial.printf("frontdist[%d] = %d\n", FRONT_DIST_ARRAY_SIZE - 1 - i, aFrontDist[FRONT_DIST_ARRAY_SIZE - 1 - i]);

//DEBUG!!

avgdist += aFrontDist[FRONT_DIST_ARRAY_SIZE - 1 - i];

}

//DEBUG!!

//mySerial.printf("avgdisttot = %d\n", avgdist);

//DEBUG!!

avgdist = (int)((float)avgdist / (float)FRONT_DIST_AVG_WINDOW_SIZE);

//DEBUG!!

//mySerial.printf("avgdist = %d\n", avgdist);

//DEBUG!!

return avgdist;

}

//08/12/20 Extracted inline FRONT_DIST_ARRAY init code so can be called from anywhere

void InitFrontDistArray()

{

//04/01/15 initialize 'stuck detection' arrays

//06/17/20 re-wrote for better readability

//to ensure var > STUCK_FRONT_VARIANCE_THRESHOLD for first FRONT_DIST_ARRAY_SIZE loops

//array is initialized with sawtooth from 0 to MAX_FRONT_DISTANCE_CM

int newval = 0;

int bumpval = MAX_FRONT_DISTANCE_CM / FRONT_DIST_ARRAY_SIZE;

bool bgoingUp = true;

for (int i = 0; i < FRONT_DIST_ARRAY_SIZE; i++)

{

aFrontDist[i] = newval;

//DEBUG!!

//mySerial.printf("i = %d, newval = %d, aFrontdist[%d] = %d\n", i, newval, i, aFrontDist[i]);

//DEBUG!!

if (bgoingUp)

{

if (newval < MAX_FRONT_DISTANCE_CM - bumpval) //don't want newval > MAX_FRONT_DISTANCE_CM

{

newval += bumpval;

}

else

{

bgoingUp = false;

}

else

{

if (newval > bumpval) //don't want newval < 0

{

newval -= bumpval;

}

else

{

bgoingUp = true;

}

//04/19/19 init Front_Dist_PrevVMean & Front_Dist_PrevVar to mean/var respectively

long sum = 0;

for (int i = 0; i < FRONT_DIST_ARRAY_SIZE; i++)

{

sum += aFrontDist[i]; //adds in rest of values

}

Front_Dist_PrevVMean = (float)sum / (float)FRONT_DIST_ARRAY_SIZE;

// Step2: calc new 'brute force' variance

float sumsquares = 0;

for (int i = 0; i < FRONT_DIST_ARRAY_SIZE; i++)

{

sumsquares += (aFrontDist[i] - Front_Dist_PrevVMean) * (aFrontDist[i] - Front_Dist_PrevVMean);

}

Front_Dist_PrevVar = sumsquares / FRONT_DIST_ARRAY_SIZE;

mySerial.printf("%lu: aFrontDist Init: Front_Dist_PrevVMean = %3.2f, Front_Dist_PrevVar = %3.2f\n", millis(), Front_Dist_PrevVMean, Front_Dist_PrevVar);

frontvar = Front_Dist_PrevVar; //added 03/30/21 to prevent 'stuck' at startup

}

Here is a link to the above file, plus all required library & ancillary files.

Stay tuned,

Frank

Post Views: 494

Paynter's Palace

Another Try at Wall Offset Tracking, Part II

26 June 2021 Update:

04 July 2021 Update:

05 July Update:

Leave a Reply Cancel reply