RT2_P3_students / Mbed 2 deprecated RT2_P3_students_G4

Template for group 4

Dependencies:   mbed

Fork of RT2_P3_students_G4 by Ruprecht Altenburger

PI_Cntrl.cpp@6:8ed679044a72, 2018-04-17 (annotated)

Committer:
altb
Date:
Tue Apr 17 11:47:35 2018 +0000
Revision:
6:8ed679044a72
Parent:
2:769ce5f06d3e
Child:
11:67af6d24c588
RT2_P3_W2, 2nd session

Who changed what in which revision?

UserRevisionLine numberNew contents of line
altb 6:8ed679044a72 1 /*
altb 6:8ed679044a72 2 PI Controller class with anti windup reset in biquad transposed direct form 2
altb 6:8ed679044a72 3 see e.g.: https://www.dsprelated.com/freebooks/filters/Four_Direct_Forms.html
altb 6:8ed679044a72 4 everything is calculated in double
altb 6:8ed679044a72 5
altb 6:8ed679044a72 6 Tn*s + 1
altb 6:8ed679044a72 7 G(s) = Kp ------------- with s ~ (1 - z^-1)/Ts
altb 6:8ed679044a72 8 Ts*s
altb 6:8ed679044a72 9 */
altb 6:8ed679044a72 10
altb 6:8ed679044a72 11 #include "PI_Cntrl.h"
altb 0:78ca29b4c49e 12
altb 0:78ca29b4c49e 13 using namespace std;
altb 0:78ca29b4c49e 14
altb 6:8ed679044a72 15 PI_Cntrl::PI_Cntrl(float Kp, float Tn, float Ts)
altb 6:8ed679044a72 16 {
altb 6:8ed679044a72 17 setCoefficients(Kp, Tn, Ts);
altb 6:8ed679044a72 18 uMax = 10000000000.0;
altb 6:8ed679044a72 19 uMin = -uMax;
altb 6:8ed679044a72 20 reset(0.0f);
altb 6:8ed679044a72 21 }
altb 0:78ca29b4c49e 22
altb 6:8ed679044a72 23 PI_Cntrl::PI_Cntrl(float Kp, float Tn, float Ts, float uMax)
altb 6:8ed679044a72 24 {
altb 6:8ed679044a72 25 setCoefficients(Kp, Tn, Ts);
altb 6:8ed679044a72 26 this->uMax = (double)uMax;
altb 6:8ed679044a72 27 uMin = -(double)uMax;
altb 6:8ed679044a72 28 reset(0.0f);
altb 6:8ed679044a72 29 }
altb 0:78ca29b4c49e 30
altb 6:8ed679044a72 31 PI_Cntrl::PI_Cntrl(float Kp, float Tn, float Ts, float uMax, float uMin)
altb 6:8ed679044a72 32 {
altb 6:8ed679044a72 33 setCoefficients(Kp, Tn, Ts);
altb 6:8ed679044a72 34 this->uMax = (double)uMax;
altb 6:8ed679044a72 35 this->uMin = (double)uMin;
altb 6:8ed679044a72 36 reset(0.0f);
altb 0:78ca29b4c49e 37 }
altb 0:78ca29b4c49e 38
altb 6:8ed679044a72 39 PI_Cntrl::~PI_Cntrl() {}
altb 6:8ed679044a72 40
altb 6:8ed679044a72 41 void PI_Cntrl::reset(float initValue)
altb 6:8ed679044a72 42 {
altb 6:8ed679044a72 43 s = (double)initValue;
altb 6:8ed679044a72 44 }
altb 6:8ed679044a72 45
altb 6:8ed679044a72 46 void PI_Cntrl::setCoefficients(float Kp, float Tn, float Ts)
altb 6:8ed679044a72 47 {
altb 6:8ed679044a72 48 b0 = (double)Kp*(1.0 + (double)Ts/(double)Tn);
altb 6:8ed679044a72 49 b1 = -(double)Kp;
altb 6:8ed679044a72 50 b2 = (double)Ts/(double)Tn;
altb 6:8ed679044a72 51 }
altb 6:8ed679044a72 52
altb 6:8ed679044a72 53 float PI_Cntrl::doStep(double e)
altb 6:8ed679044a72 54 {
altb 6:8ed679044a72 55 double u = b0*e + s; // unconstrained output
altb 6:8ed679044a72 56 double uc = u; // constrained output
altb 6:8ed679044a72 57 if(u > uMax) uc = uMax;
altb 6:8ed679044a72 58 else if(u < uMin) uc = uMin;
altb 6:8ed679044a72 59 s = b1*e + u - b2*(u - uc);
altb 6:8ed679044a72 60 return (float)uc;
altb 6:8ed679044a72 61 }