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
}

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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

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04 July 2021 Update:

05 July Update:

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