David's line following code from the LVBots competition, 2015.
Dependencies: GeneralDebouncer Pacer PololuEncoder mbed
Fork of DeadReckoning by
main.cpp
- Committer:
- DavidEGrayson
- Date:
- 2014-03-01
- Revision:
- 27:2456f68be679
- Parent:
- 26:7e7c376a7446
- Child:
- 28:4374035df5e0
File content as of revision 27:2456f68be679:
#include <mbed.h> #include <Pacer.h> #include <GeneralDebouncer.h> #include <math.h> #include "main.h" #include "motors.h" #include "encoders.h" #include "leds.h" #include "pc_serial.h" #include "test.h" #include "reckoner.h" #include "buttons.h" #include "line_tracker.h" Reckoner reckoner; LineTracker lineTracker; const int16_t drivingSpeed = 300; void setLeds(bool v1, bool v2, bool v3, bool v4) { led1 = v1; led2 = v2; led3 = v3; led4 = v4; } int __attribute__((noreturn)) main() { pc.baud(115200); // Enable pull-ups on encoder pins and give them a chance to settle. encodersInit(); motorsInit(); buttonsInit(); // Test routines //testMotors(); //testEncoders(); //testLineSensors(); //testReckoner(); //testButtons(); //testDriveHome(); //testFinalSettleIn(); //testCalibrate(); // Real routines for the contest. setLeds(1, 0, 0, 0); waitForSignalToStart(); setLeds(0, 1, 0, 0); loadCalibrationAndFindLine(); //findLineAndCalibrate(); //setLeds(1, 1, 0, 0); //turnRightToFindLine(); setLeds(0, 0, 1, 0); followLineToEnd(); setLeds(1, 0, 1, 0); driveHomeAlmost(); setLeds(0, 1, 1, 0); finalSettleIn(); setLeds(1, 1, 1, 1); while(1){} } void updateReckonerFromEncoders() { while(encoderBuffer.hasEvents()) { PololuEncoderEvent event = encoderBuffer.readEvent(); switch(event) { case ENCODER_LEFT | POLOLU_ENCODER_EVENT_INC: reckoner.handleTickLeftForward(); break; case ENCODER_LEFT | POLOLU_ENCODER_EVENT_DEC: reckoner.handleTickLeftBackward(); break; case ENCODER_RIGHT | POLOLU_ENCODER_EVENT_INC: reckoner.handleTickRightForward(); break; case ENCODER_RIGHT | POLOLU_ENCODER_EVENT_DEC: reckoner.handleTickRightBackward(); break; } } } float magnitude() { return sqrt((float)reckoner.x * reckoner.x + (float)reckoner.y * reckoner.y); } float dotProduct() { float s = (float)reckoner.sin / (1 << 30); float c = (float)reckoner.cos / (1 << 30); float magn = magnitude(); if (magn == 0){ return 0; } return ((float)reckoner.x * c + (float)reckoner.y * s) / magn; } // The closer this is to zero, the closer we are to pointing towards the home position. // It is basically a cross product of the two vectors (x, y) and (cos, sin). float determinant() { // TODO: get rid of the magic numbers here (i.e. 30) float s = (float)reckoner.sin / (1 << 30); float c = (float)reckoner.cos / (1 << 30); return (reckoner.x * s - reckoner.y * c) / magnitude(); } int16_t reduceSpeed(int16_t speed, int32_t reduction) { if (reduction > speed) { return 0; } else { return speed - reduction; } } // Returns true if each line sensor has one third of a volt of difference between the // maximum seen value and the minimum. bool calibrationLooksGood() { for(uint8_t s = 0; s < LINE_SENSOR_COUNT; s++) { uint16_t contrast = lineTracker.calibratedMaximum[s] - lineTracker.calibratedMinimum[s]; if (contrast < 9929) // 0xFFFF*0.5/3.3 = 9929 { return false; } } return true; } void waitForSignalToStart() { while(!button1DefinitelyPressed()) { updateReckonerFromEncoders(); } reckoner.reset(); } // Keep the robot pointing the in the right direction (1, 0). // This should basically keep it going straight. void updateMotorsToDriveStraight() { const int32_t straightDriveStrength = 1000; int16_t speedLeft = drivingSpeed; int16_t speedRight = drivingSpeed; int32_t reduction = reckoner.sin / (1<<15) * straightDriveStrength / (1 << 15); if (reduction > 0) { speedRight = reduceSpeed(speedRight, reduction); } else { speedLeft = reduceSpeed(speedLeft, -reduction); } motorsSpeedSet(speedLeft, speedRight); } void loadCalibrationAndFindLine() { lineTracker.calibratedMinimum[0] = 34872; lineTracker.calibratedMinimum[1] = 29335; lineTracker.calibratedMinimum[2] = 23845; lineTracker.calibratedMaximum[0] = 59726; lineTracker.calibratedMaximum[1] = 60110; lineTracker.calibratedMaximum[2] = 58446; GeneralDebouncer lineStatus(10000); while(1) { lineTracker.read(); lineTracker.updateCalibration(); updateReckonerFromEncoders(); updateMotorsToDriveStraight(); lineStatus.update(lineTracker.getLineVisible()); if(lineStatus.getState() == true && lineStatus.getTimeInCurrentStateMicroseconds() > 100000) { break; } } } // THIS IS DEPRECATED. Instead we are using loadCalibrationAndFindLine. void findLineAndCalibrate() { Timer timer; timer.start(); Timer goodCalibrationTimer; bool goodCalibration = false; while(1) { lineTracker.read(); lineTracker.updateCalibration(); updateReckonerFromEncoders(); updateMotorsToDriveStraight(); if (goodCalibration) { if(goodCalibrationTimer.read_ms() >= 300) { // The calibration was good and we traveled for a bit of time after that, // so we must be a bit over the line. break; } } else { if(calibrationLooksGood()) { goodCalibration = true; goodCalibrationTimer.start(); } } } } void turnRightToFindLine() { while(1) { lineTracker.read(); lineTracker.updateCalibration(); updateReckonerFromEncoders(); if(lineTracker.getLineVisible()) { break; } motorsSpeedSet(300, 100); } } void followLineToEnd() { Timer timer; timer.start(); GeneralDebouncer lineStatus(10000); const uint32_t lineDebounceTime = 100000; const int followLineStrength = 300; while(1) { lineTracker.read(); updateReckonerFromEncoders(); lineStatus.update(lineTracker.getLineVisible()); bool lostLine = lineStatus.getState() == false && lineStatus.getTimeInCurrentStateMicroseconds() > lineDebounceTime; if(lostLine && timer.read_us() >= 300000) { break; } int16_t speedLeft = drivingSpeed; int16_t speedRight = drivingSpeed; int16_t reduction = (lineTracker.getLinePosition() - 1500) * followLineStrength / 1500; if(reduction < 0) { speedLeft = reduceSpeed(speedLeft, -reduction); } else { speedRight = reduceSpeed(speedRight, reduction); } motorsSpeedSet(speedLeft, speedRight); } } void driveHomeAlmost() { Timer timer; timer.start(); while(1) { updateReckonerFromEncoders(); float magn = magnitude(); if (magn < (1<<17)) { // We are within 8 encoder ticks, so go to the next step. break; } float det = determinant(); int16_t speedLeft = drivingSpeed; int16_t speedRight = drivingSpeed; if (magn < (1<<20)) // Within 64 encoder ticks of the origin, so slow down. { int16_t reduction = (1 - magn/(1<<20)) * drivingSpeed; speedLeft = reduceSpeed(speedLeft, reduction); speedRight = reduceSpeed(speedRight, reduction); } if (det > 0) { speedLeft = reduceSpeed(speedLeft, det * 1000); } else { speedRight = reduceSpeed(speedRight, -det * 1000); } motorsSpeedSet(speedLeft, speedRight); } motorsSpeedSet(0, 0); } void finalSettleIn() { const int16_t settleSpeed = 300; const int16_t settleModificationStrength = 150; Timer timer; timer.start(); // State 0: rotating // State 1: Trying to get into final orientation: want [cos, sin] == [1<<30, 0]. uint8_t state = 0; Pacer reportPacer(200000); Pacer motorUpdatePacer(10000); float integral = 0; motorsSpeedSet(-settleSpeed, settleSpeed); // avoid waiting 10 ms before we start settling while(1) { led1 = (state == 1); updateReckonerFromEncoders(); float dot = dotProduct(); int16_t speedModification = -dot * settleModificationStrength; if (speedModification > settleModificationStrength) { speedModification = settleModificationStrength; } else if (speedModification < -settleModificationStrength) { speedModification = -settleModificationStrength; } if (state == 0 && timer.read_ms() >= 2000 && reckoner.cos > (1 << 29)) { // Stop turning and start trying to maintain the right position. state = 1; } if (state == 1 && timer.read_ms() >= 5000) { // Stop moving. break; } if (motorUpdatePacer.pace()) { int16_t rotationSpeed; if (state == 1) { float s = (float)reckoner.sin / (1 << 30); integral += s; rotationSpeed = -(s * 2400 + integral * 20); if (rotationSpeed > 300) { rotationSpeed = 300; } if (rotationSpeed < -300) { rotationSpeed = -300; } } else { rotationSpeed = settleSpeed; } int16_t speedLeft = -rotationSpeed + speedModification; int16_t speedRight = rotationSpeed + speedModification; motorsSpeedSet(speedLeft, speedRight); } if (state == 1 && reportPacer.pace()) { pc.printf("%11d %11d %11d %11d | %11f %11f\r\n", reckoner.cos, reckoner.sin, reckoner.x, reckoner.y, determinant(), dotProduct()); } } // Done! Stop moving. motorsSpeedSet(0, 0); }