This is a one axis gimbal control program that takes roll angle from an IMU and moves the gimbal brushless motor accordingly.
Dependencies: MPU6050 brushlessController_TB6612FNG ledControl2 mbed
main.cpp@2:f9f4d36c2367, 2015-07-17 (annotated)
- Committer:
- BaserK
- Date:
- Fri Jul 17 16:51:54 2015 +0000
- Revision:
- 2:f9f4d36c2367
- Parent:
- 1:2ae94169eee6
- Child:
- 3:065a064b3453
PID algorithm is added
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
BaserK | 2:f9f4d36c2367 | 1 | /* Brushless gimbal controller with IMU (MPU050) |
BaserK | 2:f9f4d36c2367 | 2 | * |
BaserK | 2:f9f4d36c2367 | 3 | * @author: Baser Kandehir |
BaserK | 2:f9f4d36c2367 | 4 | * @date: July 17, 2015 |
BaserK | 2:f9f4d36c2367 | 5 | * @license: Use this code however you'd like |
BaserK | 2:f9f4d36c2367 | 6 | * |
BaserK | 2:f9f4d36c2367 | 7 | * @description of the program: |
BaserK | 2:f9f4d36c2367 | 8 | * |
BaserK | 2:f9f4d36c2367 | 9 | * This a one axis gimbal control program that takes roll angle from an IMU |
BaserK | 2:f9f4d36c2367 | 10 | * and moves the gimbal brushless motor accordingly. Program is written with |
BaserK | 2:f9f4d36c2367 | 11 | * PID algorithm but it uses only P for the time being and response is good |
BaserK | 2:f9f4d36c2367 | 12 | * enough. Complete PID algorithm can be written by modifying gimbalPID function |
BaserK | 2:f9f4d36c2367 | 13 | * and PID constants. |
BaserK | 2:f9f4d36c2367 | 14 | * |
BaserK | 2:f9f4d36c2367 | 15 | * Microcontroller: LPC1768 |
BaserK | 2:f9f4d36c2367 | 16 | * IMU: MPU6050 |
BaserK | 2:f9f4d36c2367 | 17 | * Motor driver: 2x TB6612FNG |
BaserK | 2:f9f4d36c2367 | 18 | * |
BaserK | 2:f9f4d36c2367 | 19 | * Note: For any mistakes or comments, please contact me. |
BaserK | 2:f9f4d36c2367 | 20 | */ |
BaserK | 2:f9f4d36c2367 | 21 | |
BaserK | 0:40b56bdec1d2 | 22 | #include "mbed.h" |
BaserK | 0:40b56bdec1d2 | 23 | #include "MPU6050.h" |
BaserK | 0:40b56bdec1d2 | 24 | #include "ledControl.h" |
BaserK | 1:2ae94169eee6 | 25 | #include "brushlessController_TB6612FNG.h" |
BaserK | 0:40b56bdec1d2 | 26 | |
BaserK | 1:2ae94169eee6 | 27 | Serial pc(USBTX, USBRX); // Create terminal link |
BaserK | 1:2ae94169eee6 | 28 | MPU6050 mpu6050; // mpu6050 object from MPU6050 classs |
BaserK | 1:2ae94169eee6 | 29 | Ticker toggler1; // Ticker for led toggling |
BaserK | 1:2ae94169eee6 | 30 | Ticker filter; // Ticker for periodic call to compFilter funcçs |
BaserK | 2:f9f4d36c2367 | 31 | Ticker gimbal; // Periodic routine for PID control of gimbal system |
BaserK | 0:40b56bdec1d2 | 32 | |
BaserK | 1:2ae94169eee6 | 33 | /* Function prototypes */ |
BaserK | 0:40b56bdec1d2 | 34 | void toggle_led1(); |
BaserK | 0:40b56bdec1d2 | 35 | void toggle_led2(); |
BaserK | 0:40b56bdec1d2 | 36 | void compFilter(); |
BaserK | 2:f9f4d36c2367 | 37 | void gimbalPID(); |
BaserK | 0:40b56bdec1d2 | 38 | |
BaserK | 0:40b56bdec1d2 | 39 | float pitchAngle = 0; |
BaserK | 0:40b56bdec1d2 | 40 | float rollAngle = 0; |
BaserK | 2:f9f4d36c2367 | 41 | |
BaserK | 2:f9f4d36c2367 | 42 | /* Variables to be used in gimbalPID funct. */ |
BaserK | 2:f9f4d36c2367 | 43 | float Kp = 1; |
BaserK | 2:f9f4d36c2367 | 44 | float Ki = 0; |
BaserK | 2:f9f4d36c2367 | 45 | float Kd = 0; |
BaserK | 2:f9f4d36c2367 | 46 | float set_point = -30; // which angle camera should stay |
BaserK | 2:f9f4d36c2367 | 47 | float errorMargin = 5; // error margin in degress |
BaserK | 2:f9f4d36c2367 | 48 | float proportional = 0; |
BaserK | 2:f9f4d36c2367 | 49 | float last_proportional =0; |
BaserK | 2:f9f4d36c2367 | 50 | float integral = 0; |
BaserK | 2:f9f4d36c2367 | 51 | float derivative = 0; |
BaserK | 2:f9f4d36c2367 | 52 | float errorPID = 0; // error is already declared at mbed libraries |
BaserK | 0:40b56bdec1d2 | 53 | |
BaserK | 1:2ae94169eee6 | 54 | int main() |
BaserK | 0:40b56bdec1d2 | 55 | { |
BaserK | 1:2ae94169eee6 | 56 | pc.baud(9600); // baud rate: 9600 |
BaserK | 1:2ae94169eee6 | 57 | i2c.frequency(400000); // fast i2c: 400 kHz |
BaserK | 1:2ae94169eee6 | 58 | mpu6050.whoAmI(); // Communication test: WHO_AM_I register reading |
BaserK | 1:2ae94169eee6 | 59 | mpu6050.calibrate(accelBias,gyroBias); // Calibrate MPU6050 and load biases into bias registers |
BaserK | 1:2ae94169eee6 | 60 | pc.printf("Calibration is completed. \r\n"); |
BaserK | 1:2ae94169eee6 | 61 | mpu6050.init(); // Initialize the sensor |
BaserK | 1:2ae94169eee6 | 62 | pc.printf("MPU6050 is initialized for operation.. \r\n\r\n"); |
BaserK | 0:40b56bdec1d2 | 63 | |
BaserK | 1:2ae94169eee6 | 64 | filter.attach(&compFilter, 0.005); // Call the complementaryFilter func. every 5 ms (200 Hz sampling period) |
BaserK | 2:f9f4d36c2367 | 65 | gimbal.attach(&gimbalPID, 0.001); // Call the gimbalPID func. every 1 ms |
BaserK | 1:2ae94169eee6 | 66 | while(1) |
BaserK | 2:f9f4d36c2367 | 67 | { |
BaserK | 1:2ae94169eee6 | 68 | } |
BaserK | 0:40b56bdec1d2 | 69 | } |
BaserK | 0:40b56bdec1d2 | 70 | |
BaserK | 0:40b56bdec1d2 | 71 | void toggle_led1() {ledToggle(1);} |
BaserK | 0:40b56bdec1d2 | 72 | void toggle_led2() {ledToggle(2);} |
BaserK | 0:40b56bdec1d2 | 73 | |
BaserK | 0:40b56bdec1d2 | 74 | /* This function is created to avoid address error that caused from Ticker.attach func */ |
BaserK | 2:f9f4d36c2367 | 75 | void compFilter() {mpu6050.complementaryFilter(&pitchAngle, &rollAngle);} |
BaserK | 2:f9f4d36c2367 | 76 | |
BaserK | 2:f9f4d36c2367 | 77 | void gimbalPID() |
BaserK | 2:f9f4d36c2367 | 78 | { |
BaserK | 2:f9f4d36c2367 | 79 | bool dir; // direction of movement |
BaserK | 2:f9f4d36c2367 | 80 | |
BaserK | 2:f9f4d36c2367 | 81 | proportional = set_point - rollAngle; |
BaserK | 2:f9f4d36c2367 | 82 | integral += proportional; |
BaserK | 2:f9f4d36c2367 | 83 | derivative = proportional - last_proportional; |
BaserK | 2:f9f4d36c2367 | 84 | last_proportional = proportional; |
BaserK | 2:f9f4d36c2367 | 85 | |
BaserK | 2:f9f4d36c2367 | 86 | errorPID = (Kp * proportional) + (Ki * integral) + (Kd * derivative); |
BaserK | 2:f9f4d36c2367 | 87 | (errorPID > 0)?(dir = 1):(dir = 0); |
BaserK | 2:f9f4d36c2367 | 88 | |
BaserK | 2:f9f4d36c2367 | 89 | if(abs(errorPID) > errorMargin) // Within error margin motor wont move. This is for stabilizing the gimbal system |
BaserK | 2:f9f4d36c2367 | 90 | brushlessControl(dir, 0); // No need for a delay time because gimbalPID function is periodic |
BaserK | 2:f9f4d36c2367 | 91 | } |