Diff: main.cpp

Revision:

0:d8d055e8f830

Child:

1:823490ecf085

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Wed Aug 05 14:07:18 2015 +0000
@@ -0,0 +1,112 @@
+/*   Calculating Roll, Pitch and Yaw angles from IMU
+*
+*    @author: Baser Kandehir 
+*    @date: August 5, 2015
+*    @license: MIT license
+*     
+*   Copyright (c) 2015, Baser Kandehir, baser.kandehir@ieee.metu.edu.tr
+*
+*   Permission is hereby granted, free of charge, to any person obtaining a copy
+*   of this software and associated documentation files (the "Software"), to deal
+*   in the Software without restriction, including without limitation the rights
+*   to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+*   copies of the Software, and to permit persons to whom the Software is
+*   furnished to do so, subject to the following conditions:
+*
+*   The above copyright notice and this permission notice shall be included in
+*   all copies or substantial portions of the Software.
+*
+*   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+*   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+*   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+*   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+*   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+*   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+*   THE SOFTWARE.
+*   
+*    @description of the program: 
+*
+*   Program can calculate roll, pitch and yaw angles from the raw data that comes 
+*   from IMU. Yaw angle is compensated for tilt. All the angles are sent to the matlab
+*   for further proesssing.
+*     
+*/
+
+#include "mbed.h"
+#include "HMC5883L.h"
+#include "MPU6050.h"
+#include "ledControl.h"
+
+Serial pc(USBTX,USBRX);    
+MPU6050 mpu6050;           
+HMC5883L hmc5883l;    
+Ticker toggler1;
+Ticker filter;   
+Ticker compass;        
+
+void toggle_led1();
+void toggle_led2();
+void compFilter();
+void tiltCompensatedAngle();
+
+float pitchAngle = 0;
+float rollAngle = 0;
+float yawAngle = 0;
+
+int main() 
+{
+    pc.baud(9600);                                 // baud rate: 9600
+    mpu6050.whoAmI();                              // Communication test: WHO_AM_I register reading 
+    mpu6050.calibrate(accelBias,gyroBias);         // Calibrate MPU6050 and load biases into bias registers
+    mpu6050.init();                                // Initialize the sensor
+    hmc5883l.init();
+    filter.attach(&compFilter,    0.005);              // Call the complementaryFilter func.  every 5 ms (200 Hz sampling period)
+    compass.attach(&tiltCompensatedAngle, 0.015);      // Call the tiltCompensatedAngle func. every 15 ms (75 Hz sampling period)
+    while(1) 
+    {
+        pc.printf("%.1f,%.1f,%.1f\r\n",rollAngle,pitchAngle,yawAngle);  // send data to matlab
+        wait_ms(40);
+    }
+}
+
+void toggle_led1() {ledToggle(1);}
+void toggle_led2() {ledToggle(2);}
+
+/* This function is created to avoid address error that caused from Ticker.attach func */ 
+void compFilter() {mpu6050.complementaryFilter(&pitchAngle, &rollAngle);}
+
+/* Tilt compensated compass data */
+// Works well for tilt in +/- 50 deg range
+void tiltCompensatedAngle() 
+{   
+    float mag_Data[3], Xh, Yh;
+    hmc5883l.readMagData(mag_Data);
+    
+    Xh = mag_Data[0] * cos(rollAngle*PI/180) - mag_Data[2] * sin(rollAngle*PI/180) ;
+    
+    Yh = mag_Data[0] * sin(pitchAngle*PI/180) * sin(rollAngle*PI/180) + 
+    mag_Data[1] * cos(pitchAngle*PI/180) -
+    mag_Data[2] * sin(pitchAngle*PI/180) * cos(rollAngle*PI/180) ;
+    
+    /* Calculate the compensated heading angle */
+    double heading = atan2(Yh, Xh);
+    
+    // After calculating heading declination angle should be added to heading which is the error of the magnetic field in specific location.
+    // declinationAngle can be found here http://www.magnetic-declination.com/
+    // For Ankara (my location) declinationAngle is ~5.5 degrees (0.096 radians)
+    float declinationAngle = 0.096;
+    heading += declinationAngle;
+    
+    // Correct for when signs are reversed.
+    if(heading < 0)
+        heading += 2*PI;
+    
+    // Check for wrap due to addition of declination.
+    if(heading > 2*PI)
+        heading -= 2*PI;
+    
+    /* Convert radian to degrees */
+    heading = heading * 180 / PI;  
+    
+    yawAngle = heading; 
+}