Diff: main.cpp

Revision:

0:3ee52ce4df19

Child:

1:4afc0dd95be9

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Thu Jun 30 20:41:12 2016 +0000
@@ -0,0 +1,236 @@
+/**
+ * @file main.cpp
+ * @date June 9th, 2015
+ * @author Weimen Li
+ * @mainpage RobotBalancer
+ * This program is a demo lab for MAE 433. It controls a robot to balance it.
+ * @see main.cpp
+ */
+
+/* Inclusions */
+#include "mbed.h"
+#include "rtos.h"
+#include "HBridge.hpp"
+#include "QuadEnc.hpp"
+#include "HC06Bluetooth.hpp"
+#include "FXOS8700CQ.hpp"
+#include "dsp.h"
+#include "FixedRefresh.hpp"
+
+/* Constants */
+/// The CPR of the encoder.
+const float encoderCPR = 100.98f * 12.0f;
+/// The transmission period of the bluetooth module.
+const uint32_t BTTransmitPeriodMS = 1;
+/// The sampling period of the control system.
+const uint32_t controlSampleRateUS = 1250;
+/// The diameter of the wheels in inches
+const float wheelDiameter = 1.9f;
+
+/* Declaring objects */
+/// The quad encoder of the left motor.
+QuadEnc leftQuadEnc(PTB0, PTB1, encoderCPR);
+/// The quad encoder of the right motor.
+QuadEnc rightQuadEnc(PTC2, PTC1, encoderCPR);
+/// The H-Bridge driving the left motor.
+HBridge leftMotor(D9, D7);
+/// The H-Bridge driving the right motor.
+HBridge rightMotor(D10, D8);
+/// The accelerometer on the board
+FXOS8700CQ accelerometer(PTB3, PTB2, PTD0, PTD1);
+
+/// The Bluetooth link used to transmit data.
+HC06Bluetooth bluetooth(PTD3, PTD2);
+/// Timer to transmit timing information.
+Timer timer;
+
+/* Threads */
+/** @brief Bluetooth Transmission:
+ * This thread reads the quadrature encoder and
+ * output data and transmits it as comma-separated values over Bluetooth.
+ */
+void bluetooth_thread(void const *argument) {
+    // Timer to control how long to wait.
+    Timer waitTimer;
+    // 64-byte buffer is used to store the data. May be expanded as needed.
+    char buffer[128];
+    // The accelerometer readings.
+    float xAccel;
+    float yAccel;
+    float zAccel;
+    
+
+    // Start the timer:
+    waitTimer.start();
+    while(true) {
+        waitTimer.reset();
+        accelerometer.readAccelerometer(&xAccel, &yAccel, &zAccel);
+        // Place the CSV information in the buffer:
+        sprintf(buffer, "%f,%f,%f,%f,%f,%f\n", timer.read(), xAccel, yAccel, zAccel, leftMotor.read(), rightMotor.read());
+        // Transmit the information.
+        bluetooth.print(buffer);
+        // Wait the thread for BTTransmitPeriodMS - thread continues after this time.
+        int32_t waitTime = BTTransmitPeriodMS - waitTimer.read_ms();
+        if (waitTime < 0.) waitTime = 0;
+        Thread::wait(waitTime);
+    }
+
+}
+
+/** @brief Control Thread:
+ * This thread reads the current quadrature counts and actuates
+ * the motor through the H-Bridge.
+ */
+
+void control_thread(void const *argument) {
+        // FixedRefresh object to wait at fixed time
+    FixedRefresh fixedRefresh;
+    // The accelerometer readings.
+    float xAccel;
+    float yAccel;
+    float zAccel;
+    // The quadrature encoder readings.
+    float leftWheel;
+    float rightWheel;
+
+    /* Feedback constants: */
+    // Accelerometer feedback at n = 0;
+    const float a0 = 0.15;
+    // Accelerometer feedback at n = -1;
+    const float a1 = 0;
+    // Accelerometer feedback at n = -2;
+    const float a2 = 0;
+    // Output feedback
+    const float o1 = 0;
+    
+    /* Filtering Constants: */
+    // The block size is the number of samples processed by each tick of the digital filter.
+    // Since we work sample-by-sample in real time, the block size is 1.
+    const uint32_t BLOCK_SIZE = 1;
+ 
+    /* FIR Coefficients buffer generated using fir1() MATLAB function. */
+    const uint32_t NUM_TAPS = 241;
+    const float32_t firCoeffs32[NUM_TAPS] = { 
+    +0.0000825832f, +0.0000894684f, +0.0000968224f, +0.0001047243f, +0.0001132540f, 
+    +0.0001224923f, +0.0001325206f, +0.0001434207f, +0.0001552749f, +0.0001681654f, 
+    +0.0001821744f, +0.0001973838f, +0.0002138753f, +0.0002317296f, +0.0002510270f, 
+    +0.0002718465f, +0.0002942661f, +0.0003183624f, +0.0003442106f, +0.0003718838f, 
+    +0.0004014538f, +0.0004329897f, +0.0004665588f, +0.0005022258f, +0.0005400529f, 
+    +0.0005800994f, +0.0006224218f, +0.0006670735f, +0.0007141047f, +0.0007635622f, 
+    +0.0008154892f, +0.0008699254f, +0.0009269065f, +0.0009864647f, +0.0010486275f, 
+    +0.0011134190f, +0.0011808585f, +0.0012509612f, +0.0013237379f, +0.0013991947f, 
+    +0.0014773333f, +0.0015581504f, +0.0016416385f, +0.0017277849f, +0.0018165723f, 
+    +0.0019079784f, +0.0020019764f, +0.0020985340f, +0.0021976146f, +0.0022991768f, 
+    +0.0024031731f, +0.0025095530f, +0.0026182598f, +0.0027292324f, +0.0028424053f, 
+    +0.0029577080f, +0.0030750656f, +0.0031943982f, +0.0033156220f, +0.0034386488f, 
+    +0.0035633859f, +0.0036897366f, +0.0038176002f, +0.0039468720f, +0.0040774439f, 
+    +0.0042092041f, +0.0043420363f, +0.0044758227f, +0.0046104412f, +0.0047457665f, 
+    +0.0048816721f, +0.0050180266f, +0.0051546986f, +0.0052915523f, +0.0054284511f, 
+    +0.0055652573f, +0.0057018292f, +0.0058380268f, +0.0059737056f, +0.0061087236f, 
+    +0.0062429351f, +0.0063761952f, +0.0065083597f, +0.0066392822f, +0.0067688185f, 
+    +0.0068968232f, +0.0070231529f, +0.0071476642f, +0.0072702146f, +0.0073906644f, 
+    +0.0075088735f, +0.0076247053f, +0.0077380240f, +0.0078486968f, +0.0079565924f, 
+    +0.0080615841f, +0.0081635462f, +0.0082623558f, +0.0083578955f, +0.0084500499f, 
+    +0.0085387062f, +0.0086237583f, +0.0087051028f, +0.0087826382f, +0.0088562714f, 
+    +0.0089259110f, +0.0089914715f, +0.0090528717f, +0.0091100354f, +0.0091628926f, 
+    +0.0092113772f, +0.0092554288f, +0.0092949932f, +0.0093300194f, +0.0093604643f, 
+    +0.0093862908f, +0.0094074663f, +0.0094239628f, +0.0094357608f, +0.0094428463f, 
+    +0.0094452091f, +0.0094428463f, +0.0094357608f, +0.0094239628f, +0.0094074663f, 
+    +0.0093862908f, +0.0093604643f, +0.0093300194f, +0.0092949932f, +0.0092554288f, 
+    +0.0092113772f, +0.0091628926f, +0.0091100354f, +0.0090528717f, +0.0089914715f, 
+    +0.0089259110f, +0.0088562714f, +0.0087826382f, +0.0087051028f, +0.0086237583f, 
+    +0.0085387062f, +0.0084500499f, +0.0083578955f, +0.0082623558f, +0.0081635462f, 
+    +0.0080615841f, +0.0079565924f, +0.0078486968f, +0.0077380240f, +0.0076247053f, 
+    +0.0075088735f, +0.0073906644f, +0.0072702146f, +0.0071476642f, +0.0070231529f, 
+    +0.0068968232f, +0.0067688185f, +0.0066392822f, +0.0065083597f, +0.0063761952f, 
+    +0.0062429351f, +0.0061087236f, +0.0059737056f, +0.0058380268f, +0.0057018292f, 
+    +0.0055652573f, +0.0054284511f, +0.0052915523f, +0.0051546986f, +0.0050180266f, 
+    +0.0048816721f, +0.0047457665f, +0.0046104412f, +0.0044758227f, +0.0043420363f, 
+    +0.0042092041f, +0.0040774439f, +0.0039468720f, +0.0038176002f, +0.0036897366f, 
+    +0.0035633859f, +0.0034386488f, +0.0033156220f, +0.0031943982f, +0.0030750656f, 
+    +0.0029577080f, +0.0028424053f, +0.0027292324f, +0.0026182598f, +0.0025095530f, 
+    +0.0024031731f, +0.0022991768f, +0.0021976146f, +0.0020985340f, +0.0020019764f, 
+    +0.0019079784f, +0.0018165723f, +0.0017277849f, +0.0016416385f, +0.0015581504f, 
+    +0.0014773333f, +0.0013991947f, +0.0013237379f, +0.0012509612f, +0.0011808585f, 
+    +0.0011134190f, +0.0010486275f, +0.0009864647f, +0.0009269065f, +0.0008699254f, 
+    +0.0008154892f, +0.0007635622f, +0.0007141047f, +0.0006670735f, +0.0006224218f, 
+    +0.0005800994f, +0.0005400529f, +0.0005022258f, +0.0004665588f, +0.0004329897f, 
+    +0.0004014538f, +0.0003718838f, +0.0003442106f, +0.0003183624f, +0.0002942661f, 
+    +0.0002718465f, +0.0002510270f, +0.0002317296f, +0.0002138753f, +0.0001973838f, 
+    +0.0001821744f, +0.0001681654f, +0.0001552749f, +0.0001434207f, +0.0001325206f, 
+    +0.0001224923f, +0.0001132540f, +0.0001047243f, +0.0000968224f, +0.0000894684f, 
+    +0.0000825832f
+    };
+    /* Filter Object */
+    // The filter object used to perform the filtering.
+    FIR_f32<NUM_TAPS, BLOCK_SIZE> fir(firCoeffs32);
+    // The filtered z Acceleration
+    float32_t zAccelFiltered;
+    
+
+    // State variables
+    // System's angle at n = 0
+    float angle = 0;
+    // System's angle at n = -1
+    float angle_n1 = 0;
+    // System's angle at n = -2
+    float angle_n2 = 0;
+    // Previous system output
+    float output_n1 = 0;
+    // Position of the system.
+    float position = 0;
+    while (true) {
+        // Read the state from the accelerometer:
+        accelerometer.readAccelerometer(&xAccel, &yAccel, &zAccel);
+        // Filter the accelerometer state:
+        fir.process(&zAccel, &zAccelFiltered);
+        // Read the state from the quadrature encoder:
+        leftWheel = leftQuadEnc.getRevs();
+        rightWheel = rightQuadEnc.getRevs();
+
+        // Acquire the system's angle:
+        // angle = atan2f(yAccel, zAccel);
+        arm_sqrt_f32(2*zAccelFiltered, &angle);
+        if(yAccel < 0) {
+            angle = -angle;
+        }
+        // Acquire the system's position:
+        position = (leftWheel + rightWheel) / 2.;
+
+        // Control Law to regulate system:
+        float output = a0 * angle + a1 * angle_n1 + a2 * angle_n2 + o1 * output_n1;
+        // Write the output to the motor.
+        leftMotor.write(output);
+        rightMotor.write(output);
+
+        // Update the state variables
+        angle_n1 = angle;
+        angle_n2 = angle_n1;
+        output_n1 = output;
+
+        fixedRefresh.refresh_us(controlSampleRateUS);
+    }
+}
+
+/** @brief Main thread:
+ * This thread performs any additional initialization necessary for the declared objects.
+ * Then, it starts the threads.
+ */
+int main() {
+    /* Initialize objects */
+    // Set the offset value for the accelerometer.
+    accelerometer.setOffset(0.012, -0.032, 0.032);
+    // Start the global timer.
+    timer.start();
+
+    /* Initialize threads. */
+    // Thread priority is set as normal.
+    Thread thread(bluetooth_thread, NULL, osPriorityNormal);
+    // Thread priority is set as above normal: If the control_thread and bluetooth_thread
+    // ever want to happen at the same time, control_thread wins.
+    Thread thread2(control_thread, NULL, osPriorityAboveNormal);
+    while (true) {
+        // Main thread does nothing else, so we tell it to wait forever.
+        Thread::wait(osWaitForever);
+    }
+}