Motor control, feedback, PI controller, BiQuad filter
Dependencies: FastPWM HIDScope MODSERIAL biquadFilter mbed QEI
main.cpp
- Committer:
- 1856413
- Date:
- 2018-10-16
- Revision:
- 13:0b51846cf9e3
- Parent:
- 12:1ecd11dc2c00
- Child:
- 14:29236a33b5e4
File content as of revision 13:0b51846cf9e3:
#include "mbed.h" #include "FastPWM.h" #include "MODSERIAL.h" #include "QEI.h" #include <math.h> 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 MakeMotorRotate;*/ //Global variables volatile double measuredPosition = 0.0; volatile double referencePosition = 0.0; volatile double motorValue = 0.0; volatile double Kp = 0.0; //------------------------------------------------------------------------------ // 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) return referencePosition; } double GetMeasuredPosition() { double counts = Encoder.getPulses(); measuredPosition = ( counts / 4.0 * 64.0) * 6.28; // Rotational position in radians return measuredPosition; } double FeedbackControl(double Error) { double Kp = 20.0*potMeter2.read(); // Scale 0 to 20 // Proportional part: double u_k = Kp * Error; // Sum all parts and return it return u_k; //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); } } //----------------------------------------------------------------------------- // Ticker 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. double referencePosition = GetReferencePosition(); double measuredPosition = GetMeasuredPosition(); double motorValue = FeedbackControl(referencePosition - measuredPosition); SetMotor1(motorValue); } //----------------------------------------------------------------------------- int main() { //Initialize once pc.baud(115200); motor1MagnitudePin.period_us(60.0); // 60 microseconds PWM period: 16.7 kHz. MeasureControl.attach(MeasureAndControl, 0.01); /*MakeMotorRotate.attach(SetMotor1, 0.01);*/ //Other initializations while(true) { } }