Motor control, feedback, PI controller, BiQuad filter
Dependencies: FastPWM HIDScope MODSERIAL biquadFilter mbed QEI
main.cpp
- Committer:
- 1856413
- Date:
- 2018-10-19
- Revision:
- 18:e522dfbab4c6
- Parent:
- 17:4a0912c93771
File content as of revision 18:e522dfbab4c6:
#include "mbed.h" #include "FastPWM.h" #include "MODSERIAL.h" #include "QEI.h" #include <math.h> // Defining input and output pins MODSERIAL pc(USBTX, USBRX); DigitalOut motor1DirectionPin(D7); FastPWM motor1MagnitudePin(D6); AnalogIn potMeter1(A4); AnalogIn potMeter2(A5); InterruptIn button2(D3); QEI Encoder (D12, D13, NC, 64, QEI::X4_ENCODING); //Tickers Ticker MeasureControl; Ticker print; //Global variables // Measure volatile double measuredPosition = 0.0; volatile double referencePosition = 0.0; volatile double motorValue= 0.00; // Control volatile double Kp = 0.0; // Proportional gain. Dit maken we variabel, dit zorgt voor een grote of kleine overshoot volatile double Ki = 0.0; // Integral gain. Dit moeten we bepalen met een plot bijvoorbeeld volatile double Kd = 0.0; // Diverential gain. volatile double Ts = 0.01; // Sample time in FeedbackControl //------------------------------------------------------------------------------ // Functions double GetReferencePosition() { double potMeterIn = potMeter1.read(); referencePosition = 4.0*3.14*potMeterIn - 2.0*3.14 ; // Reference value y, scaled to -2 to 2 revolutions (or 0 to 100 pi) WAAROM? return referencePosition; } double GetMeasuredPosition() { double counts = Encoder.getPulses(); measuredPosition = ( counts / (8400)) * 6.28; // Rotational position in radians return measuredPosition; } double FeedbackControl(double Error) { static double Error_integral = 0.0; static double Error_prev = Error; /*static BiQuad LowPassFilter(..., ..., ..., ..., ...); */ // Read potmeter Kd = 20*potMeter2.read(); // Proportional part: // van 0 tot 20, waardes rond de 5 zijn het beste (minder overshoot + minder // trilling motor beste combinatie hiervan) double u_k = Kp * Error; // Integral part: Error_integral = Error_integral + Error * Ts; double u_i = Ki * Error_integral; // Derivative part: double Error_derivative = (Error - Error_prev)/Ts; double u_d = Kd * Error_derivative; /* Filtered_Error_derivative = LowPassFilter(Error_derivative); double u_d = Kd * Filtered_Error_derivative; */ Error_prev = Error; // Sum all parts and return it return u_k + u_i + u_d; //motorValue } void SetMotor1(double motorValue) { // Given -1<=motorValue<=1, this sets the PWM and direction // bits for motor 1. Positive value makes motor rotating // clockwise. motorValues outside range are truncated to // within range if (motorValue >=0) { motor1DirectionPin=1; } else { motor1DirectionPin=0; } if (fabs(motorValue)>1) { motor1MagnitudePin = 1; } else { motor1MagnitudePin = fabs(motorValue); } } //----------------------------------------------------------------------------- // Tickers void MeasureAndControl(void) { // This function determines the desired velocity, measures the // actual velocity, and controls the motor with // a simple Feedback controller. Call this from a Ticker. referencePosition = GetReferencePosition(); measuredPosition = GetMeasuredPosition(); motorValue = FeedbackControl(referencePosition - measuredPosition); SetMotor1(motorValue); } void printen() { pc.baud (115200); pc.printf("Referenceposition %f \r\n", referencePosition); pc.printf("Measured position %f \r\n", measuredPosition); pc.printf("Motorvalue/Error %f \r\n", motorValue); pc.printf("Proportional gain %f \r\n", Kp); pc.printf("Integral gain %f \r\n", Ki); pc.printf("Derivative gain %f \r\n", Kd); } //----------------------------------------------------------------------------- int main() { //Initialize once pc.baud(115200); motor1MagnitudePin.period_us(60.0); // 60 microseconds PWM period: 16.7 kHz. MeasureControl.attach(MeasureAndControl, 0.01); print.attach(printen, 3); //Other initializations while(true) { } }