Revision 0:dfea4e0e064b, committed 2017-05-22

Comitter:

beacon

Date:

Mon May 22 10:45:28 2017 +0000

Commit message:

k

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/EncoderCounter.cpp	Mon May 22 10:45:28 2017 +0000
@@ -0,0 +1,139 @@
+/*
+ * EncoderCounter.cpp
+ * Copyright (c) 2016, ZHAW
+ * All rights reserved.
+ */
+
+#include "EncoderCounter.h"
+
+using namespace std;
+
+/**
+ * Creates and initializes the driver to read the quadrature
+ * encoder counter of the STM32 microcontroller.
+ * @param a the input pin for the channel A.
+ * @param b the input pin for the channel B.
+ */
+EncoderCounter::EncoderCounter(PinName a, PinName b) {
+    
+    // check pins
+    
+    if ((a == PA_6) && (b == PC_7)) {
+        
+        // pinmap OK for TIM3 CH1 and CH2
+        
+        TIM = TIM3;
+        
+        // configure reset and clock control registers
+        
+        RCC->AHB1ENR |= RCC_AHB1ENR_GPIOCEN;    // manually enable port C (port A enabled by mbed library)
+        
+        // configure general purpose I/O registers
+        
+        GPIOA->MODER &= ~GPIO_MODER_MODER6;     // reset port A6
+        GPIOA->MODER |= GPIO_MODER_MODER6_1;    // set alternate mode of port A6
+        GPIOA->PUPDR &= ~GPIO_PUPDR_PUPDR6;     // reset pull-up/pull-down on port A6
+        GPIOA->PUPDR |= GPIO_PUPDR_PUPDR6_1;    // set input as pull-down
+        GPIOA->AFR[0] &= ~(0xF << 4*6);         // reset alternate function of port A6
+        GPIOA->AFR[0] |= 2 << 4*6;              // set alternate funtion 2 of port A6
+        
+        GPIOC->MODER &= ~GPIO_MODER_MODER7;     // reset port C7
+        GPIOC->MODER |= GPIO_MODER_MODER7_1;    // set alternate mode of port C7
+        GPIOC->PUPDR &= ~GPIO_PUPDR_PUPDR7;     // reset pull-up/pull-down on port C7
+        GPIOC->PUPDR |= GPIO_PUPDR_PUPDR7_1;    // set input as pull-down
+        GPIOC->AFR[0] &= ~0xF0000000;           // reset alternate function of port C7
+        GPIOC->AFR[0] |= 2 << 4*7;              // set alternate funtion 2 of port C7
+        
+        // configure reset and clock control registers
+        
+        RCC->APB1RSTR |= RCC_APB1RSTR_TIM3RST;  //reset TIM3 controller
+        RCC->APB1RSTR &= ~RCC_APB1RSTR_TIM3RST;
+        
+        RCC->APB1ENR |= RCC_APB1ENR_TIM3EN;     // TIM3 clock enable
+        
+    } else if ((a == PB_6) && (b == PB_7)) {
+        
+        // pinmap OK for TIM4 CH1 and CH2
+        
+        TIM = TIM4;
+        
+        // configure reset and clock control registers
+        
+        RCC->AHB1ENR |= RCC_AHB1ENR_GPIOBEN;    // manually enable port B (port A enabled by mbed library)
+        
+        // configure general purpose I/O registers
+        
+        GPIOB->MODER &= ~GPIO_MODER_MODER6;     // reset port B6
+        GPIOB->MODER |= GPIO_MODER_MODER6_1;    // set alternate mode of port B6
+        GPIOB->PUPDR &= ~GPIO_PUPDR_PUPDR6;     // reset pull-up/pull-down on port B6
+        GPIOB->PUPDR |= GPIO_PUPDR_PUPDR6_1;    // set input as pull-down
+        GPIOB->AFR[0] &= ~(0xF << 4*6);         // reset alternate function of port B6
+        GPIOB->AFR[0] |= 2 << 4*6;              // set alternate funtion 2 of port B6
+        
+        GPIOB->MODER &= ~GPIO_MODER_MODER7;     // reset port B7
+        GPIOB->MODER |= GPIO_MODER_MODER7_1;    // set alternate mode of port B7
+        GPIOB->PUPDR &= ~GPIO_PUPDR_PUPDR7;     // reset pull-up/pull-down on port B7
+        GPIOB->PUPDR |= GPIO_PUPDR_PUPDR7_1;    // set input as pull-down
+        GPIOB->AFR[0] &= ~0xF0000000;           // reset alternate function of port B7
+        GPIOB->AFR[0] |= 2 << 4*7;              // set alternate funtion 2 of port B7
+        
+        // configure reset and clock control registers
+        
+        RCC->APB1RSTR |= RCC_APB1RSTR_TIM4RST;  //reset TIM4 controller
+        RCC->APB1RSTR &= ~RCC_APB1RSTR_TIM4RST;
+        
+        RCC->APB1ENR |= RCC_APB1ENR_TIM4EN;     // TIM4 clock enable
+        
+    } else {
+        
+        printf("pinmap not found for peripheral\n");
+    }
+    
+    // configure general purpose timer 3 or 4
+    
+    TIM->CR1 = 0x0000;          // counter disable
+    TIM->CR2 = 0x0000;          // reset master mode selection
+    TIM->SMCR = TIM_SMCR_SMS_1 | TIM_SMCR_SMS_0; // counting on both TI1 & TI2 edges
+    TIM->CCMR1 = TIM_CCMR1_CC2S_0 | TIM_CCMR1_CC1S_0;
+    TIM->CCMR2 = 0x0000;        // reset capture mode register 2
+    TIM->CCER = TIM_CCER_CC2E | TIM_CCER_CC1E;
+    TIM->CNT = 0x0000;          // reset counter value
+    TIM->ARR = 0xFFFF;          // auto reload register
+    TIM->CR1 = TIM_CR1_CEN;     // counter enable
+}
+
+EncoderCounter::~EncoderCounter() {}
+
+/**
+ * Resets the counter value to zero.
+ */
+void EncoderCounter::reset() {
+    
+    TIM->CNT = 0x0000;
+}
+
+/**
+ * Resets the counter value to a given offset value.
+ * @param offset the offset value to reset the counter to.
+ */
+void EncoderCounter::reset(short offset) {
+    
+    TIM->CNT = -offset;
+}
+
+/**
+ * Reads the quadrature encoder counter value.
+ * @return the quadrature encoder counter as a signed 16-bit integer value.
+ */
+short EncoderCounter::read() {
+    
+    return (short)(-TIM->CNT);
+}
+
+/**
+ * The empty operator is a shorthand notation of the <code>read()</code> method.
+ */
+EncoderCounter::operator short() {
+    
+    return read();
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/EncoderCounter.h	Mon May 22 10:45:28 2017 +0000
@@ -0,0 +1,33 @@
+/*
+ * EncoderCounter.h
+ * Copyright (c) 2016, ZHAW
+ * All rights reserved.
+ */
+
+#ifndef ENCODER_COUNTER_H_
+#define ENCODER_COUNTER_H_
+
+#include <cstdlib>
+#include <mbed.h>
+
+/**
+ * This class implements a driver to read the quadrature
+ * encoder counter of the STM32 microcontroller.
+ */
+class EncoderCounter {
+    
+    public:
+        
+                    EncoderCounter(PinName a, PinName b);
+        virtual     ~EncoderCounter();
+        void        reset();
+        void        reset(short offset);
+        short       read();
+                    operator short();
+        
+    private:
+        
+        TIM_TypeDef*    TIM;
+};
+
+#endif /* ENCODER_COUNTER_H_ */

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/LowpassFilter.cpp	Mon May 22 10:45:28 2017 +0000
@@ -0,0 +1,110 @@
+/*
+ * LowpassFilter.cpp
+ * Copyright (c) 2016, ZHAW
+ * All rights reserved.
+ */
+
+#include "LowpassFilter.h"
+
+using namespace std;
+
+/**
+ * Creates a LowpassFilter object with a default corner frequency of 1000 [rad/s].
+ */
+LowpassFilter::LowpassFilter() {
+    
+    period = 1.0f;
+    frequency = 1000.0f;
+    
+    a11 = (1.0f+frequency*period)*exp(-frequency*period);
+    a12 = period*exp(-frequency*period);
+    a21 = -frequency*frequency*period*exp(-frequency*period);
+    a22 = (1.0f-frequency*period)*exp(-frequency*period);
+    b1 = (1.0f-(1.0f+frequency*period)*exp(-frequency*period))/frequency/frequency;
+    b2 = period*exp(-frequency*period);
+    
+    x1 = 0.0f;
+    x2 = 0.0f;
+}
+
+/**
+ * Deletes the LowpassFilter object.
+ */
+LowpassFilter::~LowpassFilter() {}
+
+/**
+ * Resets the filtered value to zero.
+ */
+void LowpassFilter::reset() {
+    
+    x1 = 0.0f;
+    x2 = 0.0f;
+}
+
+/**
+ * Resets the filtered value to a given value.
+ * @param value the value to reset the filter to.
+ */
+void LowpassFilter::reset(float value) {
+    
+    x1 = value/frequency/frequency;
+    x2 = (x1-a11*x1-b1*value)/a12;
+}
+
+/**
+ * Sets the sampling period of the filter.
+ * This is typically the sampling period of the realtime thread of a controller that uses this filter.
+ * @param the sampling period, given in [s].
+ */
+void LowpassFilter::setPeriod(float period) {
+    
+    this->period = period;
+    
+    a11 = (1.0f+frequency*period)*exp(-frequency*period);
+    a12 = period*exp(-frequency*period);
+    a21 = -frequency*frequency*period*exp(-frequency*period);
+    a22 = (1.0f-frequency*period)*exp(-frequency*period);
+    b1 = (1.0f-(1.0f+frequency*period)*exp(-frequency*period))/frequency/frequency;
+    b2 = period*exp(-frequency*period);
+}
+
+/**
+ * Sets the corner frequency of this filter.
+ * @param frequency the corner frequency of the filter in [rad/s].
+ */
+void LowpassFilter::setFrequency(float frequency) {
+    
+    this->frequency = frequency;
+    
+    a11 = (1.0f+frequency*period)*exp(-frequency*period);
+    a12 = period*exp(-frequency*period);
+    a21 = -frequency*frequency*period*exp(-frequency*period);
+    a22 = (1.0f-frequency*period)*exp(-frequency*period);
+    b1 = (1.0f-(1.0f+frequency*period)*exp(-frequency*period))/frequency/frequency;
+    b2 = period*exp(-frequency*period);
+}
+
+/**
+ * Gets the current corner frequency of this filter.
+ * @return the current corner frequency in [rad/s].
+ */
+float LowpassFilter::getFrequency() {
+    
+    return frequency;
+}
+
+/**
+ * Filters a value.
+ * @param value the original unfiltered value.
+ * @return the filtered value.
+ */
+float LowpassFilter::filter(float value) {
+
+    float x1old = x1;
+    float x2old = x2;
+    
+    x1 = a11*x1old+a12*x2old+b1*value;
+    x2 = a21*x1old+a22*x2old+b2*value;
+    
+    return frequency*frequency*x1;
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/LowpassFilter.h	Mon May 22 10:45:28 2017 +0000
@@ -0,0 +1,39 @@
+/*
+ * LowpassFilter.h
+ * Copyright (c) 2016, ZHAW
+ * All rights reserved.
+ */
+
+#ifndef LOWPASS_FILTER_H_
+#define LOWPASS_FILTER_H_
+
+#include <cstdlib>
+#include <cmath>
+
+/**
+ * This class implements a time-discrete 2nd order low-pass filter for a series of data values.
+ * This filter can typically be used within a periodic task that takes measurements that need
+ * to be filtered, like speed or position values.
+ */
+class LowpassFilter {
+    
+    public:
+    
+                LowpassFilter();
+        virtual ~LowpassFilter();
+        void    reset();
+        void    reset(float value);
+        void    setPeriod(float period);
+        void    setFrequency(float frequency);
+        float   getFrequency();
+        float   filter(float value);
+        
+    private:
+        
+        float   period;
+        float   frequency;
+        float   a11, a12, a21, a22, b1, b2;
+        float   x1, x2;
+};
+
+#endif /* LOWPASS_FILTER_H_ */

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Mon May 22 10:45:28 2017 +0000
@@ -0,0 +1,107 @@
+/*
+
+Folgendes Programm zeigt einen einfach P-Geschwindigkeitsregler
+Die DIP-Switch auf der Ruekseite des Roboters muessen dazu of "on" stehen.
+
+ACHTUNG:
+Die Motorencoder koennen nicht simultan mit den R/C-Servos gebraucht werden.
+*/
+
+
+#include "mbed.h"
+#include "EncoderCounter.h"
+#include "LowpassFilter.h"
+
+const float PERIOD = 0.001f;                    // period of control task, given in [s]
+const float COUNTS_PER_TURN = 1200.0f;          // resolution of encoder counter
+const float LOWPASS_FILTER_FREQUENCY = 300.0f;  // frequency of lowpass filter for actual speed values, given in [rad/s]
+const float KN = 40.0f;                         // speed constant of motor, given in [rpm/V]
+const float KP = 0.2f;                          // speed controller gain, given in [V/rpm]
+const float MAX_VOLTAGE = 12.0f;                // supply voltage for power stage in [V]
+const float MIN_DUTY_CYCLE = 0.02f;             // minimum allowed value for duty cycle (2%)
+const float MAX_DUTY_CYCLE = 0.98f;             // maximum allowed value for duty cycle (98%)
+
+EncoderCounter counterLeft(PB_6, PB_7);
+EncoderCounter counterRight(PA_6, PC_7);
+
+LowpassFilter speedLeftFilter;
+LowpassFilter speedRightFilter;
+
+DigitalOut enableMotorDriver(PB_2);
+PwmOut pwmLeft(PA_8);
+PwmOut pwmRight(PA_9);
+
+DigitalOut my_led(LED1);
+
+short previousValueCounterRight = 0;
+short previousValueCounterLeft = 0;
+
+float desiredSpeedLeft;
+float desiredSpeedRight;
+
+float actualSpeedLeft;
+float actualSpeedRight;
+
+void speedCtrl()
+{
+    // Berechnen die effektiven Drehzahlen der Motoren 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);
+
+    // Berechnen der Motorspannungen Uout
+    float voltageLeft = KP*(desiredSpeedLeft-actualSpeedLeft)+desiredSpeedLeft/KN;
+    float voltageRight = KP*(desiredSpeedRight-actualSpeedRight)+desiredSpeedRight/KN;
+
+    // Berechnen, Limitieren und Setzen der 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;
+}
+
+int main()
+{
+    // Initialisieren der PWM Ausgaenge pwmLeft.period(0.00005f); // PWM Periode von 50 us
+    pwmLeft.period(0.00005f); // Setzt die Periode auf 50 μs
+    pwmRight.period(0.00005f);
+    pwmLeft = 0.5f; // Duty-Cycle von 50% pwmRight.period(0.00005f); // PWM Periode von 50 us
+    pwmRight = 0.5f; // Duty-Cycle von 50%
+
+    // Initialisieren von lokalen Variabeln
+    previousValueCounterLeft = counterLeft.read();
+    previousValueCounterRight = counterRight.read();
+    speedLeftFilter.setPeriod(PERIOD);
+    speedLeftFilter.setFrequency(LOWPASS_FILTER_FREQUENCY);
+    speedRightFilter.setPeriod(PERIOD);
+    speedRightFilter.setFrequency(LOWPASS_FILTER_FREQUENCY);
+
+    desiredSpeedLeft = 0.0f;
+    desiredSpeedRight = 0.0f;
+    actualSpeedLeft = 0.0f;
+    actualSpeedRight = 0.0f;
+
+    Ticker t1;
+    t1.attach( &speedCtrl, PERIOD);
+
+    desiredSpeedLeft = 50.0f; //50 RPM
+    desiredSpeedRight = -50.0f; //50 RPM
+    enableMotorDriver = 1;
+
+    while(1) {
+        my_led = !my_led;
+        wait(0.5);
+    }
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed.bld	Mon May 22 10:45:28 2017 +0000
@@ -0,0 +1,1 @@
+https://mbed.org/users/mbed_official/code/mbed/builds/4eea097334d6
\ No newline at end of file