Spring 2014, ECE 4180 project, Georgia Institute of Technolgoy. This is the autonomous driver program for the Robotics Cat and Mouse program.

Dependencies:   IMUfilter ADXL345_I2C mbed ITG3200 USBHost mbed-rtos

Files at this revision

API Documentation at this revision

Comitter:
Strikewolf
Date:
Sun Apr 27 04:31:07 2014 +0000
Child:
1:dacf7db790f6
Commit message:
-v1.0 of human controlled car;

Changed in this revision

IMU_RPY.h Show annotated file Show diff for this revision Revisions of this file
IMUfilter.lib Show annotated file Show diff for this revision Revisions of this file
main.cpp Show annotated file Show diff for this revision Revisions of this file
mbed.bld Show annotated file Show diff for this revision Revisions of this file
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/IMU_RPY.h	Sun Apr 27 04:31:07 2014 +0000
@@ -0,0 +1,281 @@
+    
+
+    /**
+     * IMU filter example.
+     *
+     * Calculate the roll, pitch and yaw angles.
+     */
+    #include "IMUfilter.h"
+    #include "ADXL345_I2C.h"
+    #include "ITG3200.h"
+     
+    //Gravity at Earth's surface in m/s/s
+    #define g0 9.812865328
+    //Number of samples to average.
+    #define SAMPLES 4
+    //Number of samples to be averaged for a null bias calculation
+    //during calibration.
+    #define CALIBRATION_SAMPLES 128
+    //Convert from radians to degrees.
+    #define toDegrees(x) (x * 57.2957795)
+    //Convert from degrees to radians.
+    #define toRadians(x) (x * 0.01745329252)
+    //ITG-3200 sensitivity is 14.375 LSB/(degrees/sec).
+    #define GYROSCOPE_GAIN (1 / 14.375)
+    //Full scale resolution on the ADXL345 is 4mg/LSB.
+    #define ACCELEROMETER_GAIN (0.004 * g0)
+    //Sampling gyroscope at 200Hz.
+    #define GYRO_RATE   0.005
+    //Sampling accelerometer at 200Hz.
+    #define ACC_RATE    0.005
+    //Updating filter at 40Hz.
+    #define FILTER_RATE 0.1
+     
+    //At rest the gyroscope is centred around 0 and goes between about
+    //-5 and 5 counts. As 1 degrees/sec is ~15 LSB, error is roughly
+    //5/15 = 0.3 degrees/sec.
+    IMUfilter imuFilter(FILTER_RATE, 0.3);
+    ADXL345_I2C accelerometer(p28, p27);
+    ITG3200 gyroscope(p28, p27);
+    Ticker accelerometerTicker;
+    Ticker gyroscopeTicker;
+    Ticker filterTicker;
+     
+    //Offsets for the gyroscope.
+    //The readings we take when the gyroscope is stationary won't be 0, so we'll
+    //average a set of readings we do get when the gyroscope is stationary and
+    //take those away from subsequent readings to ensure the gyroscope is offset
+    //or "biased" to 0.
+    double w_xBias;
+    double w_yBias;
+    double w_zBias;
+     
+    //Offsets for the accelerometer.
+    //Same as with the gyroscope.
+    double a_xBias;
+    double a_yBias;
+    double a_zBias;
+     
+    //Accumulators used for oversampling and then averaging.
+    volatile double a_xAccumulator = 0;
+    volatile double a_yAccumulator = 0;
+    volatile double a_zAccumulator = 0;
+    volatile double w_xAccumulator = 0;
+    volatile double w_yAccumulator = 0;
+    volatile double w_zAccumulator = 0;
+     
+    //Accelerometer and gyroscope readings for x, y, z axes.
+    volatile double a_x;
+    volatile double a_y;
+    volatile double a_z;
+    volatile double w_x;
+    volatile double w_y;
+    volatile double w_z;
+     
+    //Buffer for accelerometer readings.
+    int readings[3];
+    //Number of accelerometer samples we're on.
+    int accelerometerSamples = 0;
+    //Number of gyroscope samples we're on.
+    int gyroscopeSamples = 0;
+     
+    /**
+     * Prototypes
+     */
+    //Set up the ADXL345 appropriately.
+    void initializeAcceleromter(void);
+    //Calculate the null bias.
+    void calibrateAccelerometer(void);
+    //Take a set of samples and average them.
+    void sampleAccelerometer(void);
+    //Set up the ITG3200 appropriately.
+    void initializeGyroscope(void);
+    //Calculate the null bias.
+    void calibrateGyroscope(void);
+    //Take a set of samples and average them.
+    void sampleGyroscope(void);
+    //Update the filter and calculate the Euler angles.
+    void filter(void);
+     
+    void initializeAccelerometer(void)
+    {
+     
+        //Go into standby mode to configure the device.
+        accelerometer.setPowerControl(0x00);
+        //Full resolution, +/-16g, 4mg/LSB.
+        accelerometer.setDataFormatControl(0x0B);
+        //200Hz data rate.
+        accelerometer.setDataRate(ADXL345_200HZ);
+        //Measurement mode.
+        accelerometer.setPowerControl(0x08);
+        //See http://www.analog.com/static/imported-files/application_notes/AN-1077.pdf
+        wait_ms(22);
+     
+    }
+     
+    void sampleAccelerometer(void)
+    {
+     
+        //Have we taken enough samples?
+        if (accelerometerSamples == SAMPLES) {
+     
+            //Average the samples, remove the bias, and calculate the acceleration
+            //in m/s/s.
+            a_x = ((a_xAccumulator / SAMPLES) - a_xBias) * ACCELEROMETER_GAIN;
+            a_y = ((a_yAccumulator / SAMPLES) - a_yBias) * ACCELEROMETER_GAIN;
+            a_z = ((a_zAccumulator / SAMPLES) - a_zBias) * ACCELEROMETER_GAIN;
+     
+            a_xAccumulator = 0;
+            a_yAccumulator = 0;
+            a_zAccumulator = 0;
+            accelerometerSamples = 0;
+     
+        } else {
+            //Take another sample.
+            accelerometer.getOutput(readings);
+     
+            a_xAccumulator += (int16_t) readings[0];
+            a_yAccumulator += (int16_t) readings[1];
+            a_zAccumulator += (int16_t) readings[2];
+     
+            accelerometerSamples++;
+     
+        }
+     
+    }
+     
+    void calibrateAccelerometer(void)
+    {
+     
+        a_xAccumulator = 0;
+        a_yAccumulator = 0;
+        a_zAccumulator = 0;
+     
+        //Take a number of readings and average them
+        //to calculate the zero g offset.
+        for (int i = 0; i < CALIBRATION_SAMPLES; i++) {
+     
+            accelerometer.getOutput(readings);
+     
+            a_xAccumulator += (int16_t) readings[0];
+            a_yAccumulator += (int16_t) readings[1];
+            a_zAccumulator += (int16_t) readings[2];
+     
+            wait(ACC_RATE);
+     
+        }
+     
+        a_xAccumulator /= CALIBRATION_SAMPLES;
+        a_yAccumulator /= CALIBRATION_SAMPLES;
+        a_zAccumulator /= CALIBRATION_SAMPLES;
+     
+        //At 4mg/LSB, 250 LSBs is 1g.
+        a_xBias = a_xAccumulator;
+        a_yBias = a_yAccumulator;
+        a_zBias = (a_zAccumulator - 250);
+     
+        a_xAccumulator = 0;
+        a_yAccumulator = 0;
+        a_zAccumulator = 0;
+     
+    }
+     
+    void initializeGyroscope(void)
+    {
+     
+        //Low pass filter bandwidth of 42Hz.
+        gyroscope.setLpBandwidth(LPFBW_42HZ);
+        //Internal sample rate of 200Hz. (1kHz / 5).
+        gyroscope.setSampleRateDivider(4);
+     
+    }
+     
+    void calibrateGyroscope(void)
+    {
+     
+        w_xAccumulator = 0;
+        w_yAccumulator = 0;
+        w_zAccumulator = 0;
+     
+        //Take a number of readings and average them
+        //to calculate the gyroscope bias offset.
+        for (int i = 0; i < CALIBRATION_SAMPLES; i++) {
+     
+            w_xAccumulator += gyroscope.getGyroX();
+            w_yAccumulator += gyroscope.getGyroY();
+            w_zAccumulator += gyroscope.getGyroZ();
+            wait(GYRO_RATE);
+     
+        }
+     
+        //Average the samples.
+        w_xAccumulator /= CALIBRATION_SAMPLES;
+        w_yAccumulator /= CALIBRATION_SAMPLES;
+        w_zAccumulator /= CALIBRATION_SAMPLES;
+     
+        w_xBias = w_xAccumulator;
+        w_yBias = w_yAccumulator;
+        w_zBias = w_zAccumulator;
+     
+        w_xAccumulator = 0;
+        w_yAccumulator = 0;
+        w_zAccumulator = 0;
+     
+    }
+     
+    void sampleGyroscope(void)
+    {
+     
+        //Have we taken enough samples?
+        if (gyroscopeSamples == SAMPLES) {
+     
+            //Average the samples, remove the bias, and calculate the angular
+            //velocity in rad/s.
+            w_x = toRadians(((w_xAccumulator / SAMPLES) - w_xBias) * GYROSCOPE_GAIN);
+            w_y = toRadians(((w_yAccumulator / SAMPLES) - w_yBias) * GYROSCOPE_GAIN);
+            w_z = toRadians(((w_zAccumulator / SAMPLES) - w_zBias) * GYROSCOPE_GAIN);
+     
+            w_xAccumulator = 0;
+            w_yAccumulator = 0;
+            w_zAccumulator = 0;
+            gyroscopeSamples = 0;
+     
+        } else {
+            //Take another sample.
+            w_xAccumulator += gyroscope.getGyroX();
+            w_yAccumulator += gyroscope.getGyroY();
+            w_zAccumulator += gyroscope.getGyroZ();
+     
+            gyroscopeSamples++;
+     
+        }
+     
+    }
+     
+    void filter(void)
+    {
+     
+        //Update the filter variables.
+        imuFilter.updateFilter(w_y, w_x, w_z, a_y, a_x, a_z);
+        //Calculate the new Euler angles.
+        imuFilter.computeEuler();
+     
+    }
+     
+    void rpy_init()
+    {
+        //Initialize inertial sensors.
+        initializeAccelerometer();
+        calibrateAccelerometer();
+        initializeGyroscope();
+        //calibrateGyroscope();
+     
+     
+       /* //Set up timers.
+        //Accelerometer data rate is 200Hz, so we'll sample at this speed.
+        accelerometerTicker.attach(&sampleAccelerometer, 0.005);
+        //Gyroscope data rate is 200Hz, so we'll sample at this speed.
+        gyroscopeTicker.attach(&sampleGyroscope, 0.005);
+        //Update the filter variables at the correct rate.
+        filterTicker.attach(&filter, FILTER_RATE);*/
+    }
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/IMUfilter.lib	Sun Apr 27 04:31:07 2014 +0000
@@ -0,0 +1,1 @@
+http://mbed.org/users/aberk/code/IMUfilter/#8a920397b510
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Sun Apr 27 04:31:07 2014 +0000
@@ -0,0 +1,203 @@
+#include "mbed.h"
+
+//Radio Calibration Signals - Need to implement calibration routine...
+#define CHAN2_MID 1470  //Elevator Midpoint
+#define CHAN1_MID 1470  //Rudder Midpoint
+#define DEADZONE 105
+#define MAXMIN_OFFSET 400
+
+//Drive Modes
+typedef enum {FORWARD, REVERSE, STOP, CENTERLEFT, CENTERRIGHT} DRIVEMODE;
+DRIVEMODE mode;
+float xpwm, ypwm;
+
+//H-bridge
+PwmOut rightMotorPWM(p22);  //Channel A
+PwmOut leftMotorPWM(p21);   //Channel B
+DigitalOut leftMotor1(p23);
+DigitalOut leftMotor2(p24);
+DigitalOut rightMotor1(p25);
+DigitalOut rightMotor2(p26);
+
+//Radio 
+Serial pc(USBTX, USBRX);
+DigitalIn rudder(p11);
+DigitalIn elevator(p12);
+
+//Xbee
+Serial xbee(p13, p14);
+DigitalOut xbeeReset(p15);
+
+void setTurnLeft(float speed) {
+    //Set speed
+    rightMotorPWM = speed;
+    leftMotorPWM = speed;
+    
+    //Set motor function
+    leftMotor1 = 0;
+    leftMotor2 = 1;
+    rightMotor1 = 1;
+    rightMotor2 = 0;
+}
+
+void setTurnRight(float speed) {
+    //Set speed
+    rightMotorPWM = speed;
+    leftMotorPWM = speed;
+    
+    //Set motor function
+    leftMotor1 = 1;
+    leftMotor2 = 0;
+    rightMotor1 = 0;
+    rightMotor2 = 1;
+}
+
+//Stop with braking
+void stop() {
+    rightMotorPWM = 0;
+    leftMotorPWM = 0;
+    leftMotor1 = 0;
+    leftMotor2 = 1;
+    rightMotor1 = 1;
+    rightMotor2 = 0;
+}
+
+
+int getRadioX() {
+    Timer timer;
+    timer.reset();
+    int dur;
+    while(!rudder);
+    timer.start();
+    while(rudder);
+    dur = timer.read_us();
+    return dur;
+}
+
+int getRadioY() {
+    Timer timer;
+    timer.reset();
+    int dur;
+    while(!elevator);
+    timer.start();
+    while(elevator);
+    dur = timer.read_us();
+    return dur;
+}
+
+//Primary function for setting motors for radio driving
+void radioDrive() {
+    int radioY = getRadioY();
+    int radioX = getRadioX();
+    
+    //Identify drive mode from radio values
+    if (radioY < CHAN2_MID - DEADZONE)
+        mode = FORWARD;
+    if (radioY > CHAN2_MID + DEADZONE)
+        mode = REVERSE;
+    if (radioY < CHAN2_MID + DEADZONE && radioY > CHAN2_MID - DEADZONE &&
+        radioX < CHAN1_MID - DEADZONE)
+        mode = CENTERLEFT;
+    if (radioY < CHAN2_MID + DEADZONE && radioY > CHAN2_MID - DEADZONE &&
+        radioX > CHAN1_MID + DEADZONE)
+        mode = CENTERRIGHT;        
+    if (radioY < CHAN2_MID + DEADZONE && radioY > CHAN2_MID - DEADZONE &&
+        radioX < CHAN1_MID + DEADZONE && radioX > CHAN1_MID - DEADZONE)
+        mode = STOP;
+        
+    //Normalize values for PWM magnitude
+    xpwm = abs((float)radioX - CHAN1_MID) / MAXMIN_OFFSET;
+    ypwm = abs((float)radioY - CHAN2_MID) / MAXMIN_OFFSET;
+        
+    //Set Motors Accordingly
+    switch(mode) {
+        case FORWARD:
+            //Handle variable turns
+            if (radioX > CHAN1_MID + DEADZONE) {
+                rightMotorPWM = ypwm - 0.8*xpwm;
+                leftMotorPWM = ypwm;
+            } else if (radioX < CHAN1_MID - DEADZONE) {
+                rightMotorPWM = ypwm;
+                leftMotorPWM = ypwm - 0.8*xpwm;
+            } else {
+                rightMotorPWM = ypwm;
+                leftMotorPWM = ypwm; 
+            }
+            leftMotor1 =  0;
+            leftMotor2 = 1;
+            rightMotor1 = 0;
+            rightMotor2 = 1;
+            break;
+        
+        case REVERSE:
+            //Handle variable turns
+            if (radioX > CHAN1_MID + DEADZONE) {
+                rightMotorPWM = ypwm - 0.8*xpwm;
+                leftMotorPWM = ypwm;
+            } else if (radioX < CHAN1_MID - DEADZONE) {
+                rightMotorPWM = ypwm;
+                leftMotorPWM = ypwm - 0.8*xpwm;
+            } else {
+                rightMotorPWM = ypwm;
+                leftMotorPWM = ypwm; 
+            }
+            leftMotor1 =  1;
+            leftMotor2 = 0;
+            rightMotor1 = 1;
+            rightMotor2 = 0;
+            break;
+            
+        case CENTERRIGHT:
+            rightMotorPWM = xpwm;
+            leftMotorPWM = xpwm;
+            leftMotor1 = 1;
+            leftMotor2 = 0;
+            rightMotor1 = 0;
+            rightMotor2 = 1;
+            break;
+
+        case CENTERLEFT:
+            rightMotorPWM = xpwm;
+            leftMotorPWM = xpwm;
+            leftMotor1 = 0;
+            leftMotor2 = 1;
+            rightMotor1 = 1;
+            rightMotor2 = 0;
+            break;
+
+        case STOP:
+            rightMotorPWM = 0;
+            leftMotorPWM = 0;
+            leftMotor1 = 0;
+            leftMotor2 = 1;
+            rightMotor1 = 1;
+            rightMotor2 = 0;
+            break;
+    }
+}
+
+//Transmit position and heading
+void xbeeTelemetry() {
+    xbee.printf("Human Update \r\n");   
+    wait_ms(10);
+}
+
+bool isGameOver() {
+    return xbee.readable();
+}
+        
+
+
+int main() {
+    
+    //Init Xbee
+    xbeeReset = 0;
+    wait_ms(1);
+    xbeeReset = 1;
+    wait_ms(1);
+    
+    while(1) {
+        xbee.printf("HELLO!\r\n");
+        wait(0.1);
+    }
+}
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed.bld	Sun Apr 27 04:31:07 2014 +0000
@@ -0,0 +1,1 @@
+http://mbed.org/users/mbed_official/code/mbed/builds/6473597d706e
\ No newline at end of file