Diff: Controller.cpp

Revision:

37:698d6b73b50c

Child:

38:8aae5cbcf25f

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Controller.cpp	Tue May 10 10:04:51 2022 +0200
@@ -0,0 +1,192 @@
+/*
+ * Controller.cpp
+ * Copyright (c) 2022, ZHAW
+ * All rights reserved.
+ */
+
+#include "Controller.h"
+
+using namespace std;
+
+const float Controller::PERIOD = 0.001f;                    // period of control task, given in [s]
+const float Controller::M_PI = 3.14159265f;                 // the mathematical constant PI
+const float Controller::WHEEL_DISTANCE = 0.190f;            // distance between wheels, given in [m]
+const float Controller::WHEEL_RADIUS = 0.0375f;             // radius of wheels, given in [m]
+const float Controller::MAXIMUM_VELOCITY = 500.0;           // maximum wheel velocity, given in [rpm]
+const float Controller::MAXIMUM_ACCELERATION = 1000.0;       // maximum wheel acceleration, given in [rpm/s]
+const float Controller::COUNTS_PER_TURN = 1200.0f;          // encoder resolution (pololu motors: 1200.0f, maxon motors: 86016.0f)
+const float Controller::LOWPASS_FILTER_FREQUENCY = 300.0f;  // given in [rad/s]
+const float Controller::KN = 40.0f;                         // speed constant in [rpm/V] (pololu motors: 40.0f, maxon motors: 45.0f)
+const float Controller::KP = 0.15f;                         // speed control parameter
+const float Controller::MAX_VOLTAGE = 12.0f;                // battery voltage in [V]
+const float Controller::MIN_DUTY_CYCLE = 0.02f;             // minimum duty-cycle
+const float Controller::MAX_DUTY_CYCLE = 0.98f;             // maximum duty-cycle
+
+/**
+ * Creates and initialises the robot controller.
+ * @param pwmLeft a reference to the pwm output for the left motor.
+ * @param pwmRight a reference to the pwm output for the right motor.
+ * @param counterLeft a reference to the encoder counter of the left motor.
+ * @param counterRight a reference to the encoder counter of the right motor.
+ */
+Controller::Controller(PwmOut& pwmLeft, PwmOut& pwmRight, EncoderCounterROME2& counterLeft, EncoderCounterROME2& counterRight) : pwmLeft(pwmLeft), pwmRight(pwmRight), counterLeft(counterLeft), counterRight(counterRight), thread(osPriorityHigh, STACK_SIZE) {
+    
+    // initialise pwm outputs
+
+    pwmLeft.period(0.00005f);  // pwm period of 50 us
+    pwmLeft = 0.5f;            // duty-cycle of 50%
+
+    pwmRight.period(0.00005f); // pwm period of 50 us
+    pwmRight = 0.5f;           // duty-cycle of 50%
+
+    // initialise local variables
+
+    translationalVelocity = 0.0f;
+    rotationalVelocity = 0.0f;
+
+    actualTranslationalVelocity = 0.0f;
+    actualRotationalVelocity = 0.0f;
+
+    desiredSpeedLeft = 0.0f;
+    desiredSpeedRight = 0.0f;
+
+    actualSpeedLeft = 0.0f;
+    actualSpeedRight = 0.0f;
+
+    motionLeft.setProfileVelocity(MAXIMUM_VELOCITY);
+    motionLeft.setProfileAcceleration(MAXIMUM_ACCELERATION);
+    motionLeft.setProfileDeceleration(MAXIMUM_ACCELERATION);
+
+    motionRight.setProfileVelocity(MAXIMUM_VELOCITY);
+    motionRight.setProfileAcceleration(MAXIMUM_ACCELERATION);
+    motionRight.setProfileDeceleration(MAXIMUM_ACCELERATION);
+
+    previousValueCounterLeft = counterLeft.read();
+    previousValueCounterRight = counterRight.read();
+
+    speedLeftFilter.setPeriod(PERIOD);
+    speedLeftFilter.setFrequency(LOWPASS_FILTER_FREQUENCY);
+
+    speedRightFilter.setPeriod(PERIOD);
+    speedRightFilter.setFrequency(LOWPASS_FILTER_FREQUENCY);
+
+    // start thread and timer interrupt
+    
+    thread.start(callback(this, &Controller::run));
+    ticker.attach(callback(this, &Controller::sendThreadFlag), PERIOD);
+}
+
+/**
+ * Deletes this Controller object.
+ */
+Controller::~Controller() {
+    
+    ticker.detach(); // stop the timer interrupt
+}
+
+/**
+ * Sets the desired translational velocity of the robot.
+ * @param velocity the desired translational velocity, given in [m/s].
+ */
+void Controller::setTranslationalVelocity(float velocity) {
+    
+    this->translationalVelocity = velocity;
+}
+
+/**
+ * Sets the desired rotational velocity of the robot.
+ * @param velocity the desired rotational velocity, given in [rad/s].
+ */
+void Controller::setRotationalVelocity(float velocity) {
+    
+    this->rotationalVelocity = velocity;
+}
+
+/**
+ * Gets the actual translational velocity of the robot.
+ * @return the actual translational velocity, given in [m/s].
+ */
+float Controller::getActualTranslationalVelocity() {
+    
+    return actualTranslationalVelocity;
+}
+
+/**
+ * Gets the actual rotational velocity of the robot.
+ * @return the actual rotational velocity, given in [rad/s].
+ */
+float Controller::getActualRotationalVelocity() {
+    
+    return actualRotationalVelocity;
+}
+
+/**
+ * This method is called by the ticker timer interrupt service routine.
+ * It sends a flag to the thread to make it run again.
+ */
+void Controller::sendThreadFlag() {
+    
+    thread.flags_set(threadFlag);
+}
+
+/**
+ * This is an internal method of the controller that is running periodically.
+ */
+void Controller::run() {
+
+    while (true) {
+        
+        // wait for the periodic thread flag
+        
+        ThisThread::flags_wait_any(threadFlag);
+        
+        // calculate the values 'desiredSpeedLeft' and 'desiredSpeedRight' using the kinematic model
+        
+        desiredSpeedLeft = (translationalVelocity-WHEEL_DISTANCE/2.0f*rotationalVelocity)/WHEEL_RADIUS*60.0f/2.0f/M_PI;
+        desiredSpeedRight = -(translationalVelocity+WHEEL_DISTANCE/2.0f*rotationalVelocity)/WHEEL_RADIUS*60.0f/2.0f/M_PI;
+        
+        // calculate planned speedLeft and speedRight values using the motion planner
+        
+        motionLeft.incrementToVelocity(desiredSpeedLeft, PERIOD);
+        motionRight.incrementToVelocity(desiredSpeedRight, PERIOD);
+        
+        desiredSpeedLeft = motionLeft.getVelocity();
+        desiredSpeedRight = motionRight.getVelocity();
+        
+        // calculate the actual speed of the motors in [rpm]
+
+        short valueCounterLeft = counterLeft.read();
+        short valueCounterRight = counterRight.read();
+
+        short countsInPastPeriodLeft = valueCounterLeft-previousValueCounterLeft;
+        short countsInPastPeriodRight = valueCounterRight-previousValueCounterRight;
+
+        previousValueCounterLeft = valueCounterLeft;
+        previousValueCounterRight = valueCounterRight;
+
+        actualSpeedLeft = speedLeftFilter.filter((float)countsInPastPeriodLeft/COUNTS_PER_TURN/PERIOD*60.0f);
+        actualSpeedRight = speedRightFilter.filter((float)countsInPastPeriodRight/COUNTS_PER_TURN/PERIOD*60.0f);
+
+        // calculate desired motor voltages Uout
+
+        float voltageLeft = KP*(desiredSpeedLeft-actualSpeedLeft)+desiredSpeedLeft/KN;
+        float voltageRight = KP*(desiredSpeedRight-actualSpeedRight)+desiredSpeedRight/KN;
+
+        // calculate, limit and set the duty-cycle
+
+        float dutyCycleLeft = 0.5f+0.5f*voltageLeft/MAX_VOLTAGE;
+        if (dutyCycleLeft < MIN_DUTY_CYCLE) dutyCycleLeft = MIN_DUTY_CYCLE;
+        else if (dutyCycleLeft > MAX_DUTY_CYCLE) dutyCycleLeft = MAX_DUTY_CYCLE;
+        pwmLeft = dutyCycleLeft;
+
+        float dutyCycleRight = 0.5f+0.5f*voltageRight/MAX_VOLTAGE;
+        if (dutyCycleRight < MIN_DUTY_CYCLE) dutyCycleRight = MIN_DUTY_CYCLE;
+        else if (dutyCycleRight > MAX_DUTY_CYCLE) dutyCycleRight = MAX_DUTY_CYCLE;
+        pwmRight = dutyCycleRight;
+
+        // calculate the values 'actualTranslationalVelocity' and 'actualRotationalVelocity' using the kinematic model
+
+        actualTranslationalVelocity = (actualSpeedLeft-actualSpeedRight)*2.0f*M_PI/60.0f*WHEEL_RADIUS/2.0f;
+        actualRotationalVelocity = (-actualSpeedRight-actualSpeedLeft)*2.0f*M_PI/60.0f*WHEEL_RADIUS/WHEEL_DISTANCE;
+    }
+}