Ruprecht Altenburger / Library_Cntrl

2nd Library

Dependents:   cuboid_balance_ros cuboid_balance mirror_actuator_V1

PI_Cntrl.cpp@3:e3b84ea63c0f, 2021-04-01 (annotated)

Committer:
altb2
Date:
Thu Apr 01 13:38:43 2021 +0000
Revision:
3:e3b84ea63c0f
Parent:
0:a201a6cd4c0c 
PIDT2 added

Who changed what in which revision?

UserRevisionLine numberNew contents of line
altb2 0:a201a6cd4c0c 1 /*
altb2 0:a201a6cd4c0c 2 PI Controller class with anti windup reset in biquad transposed direct form 2
altb2 0:a201a6cd4c0c 3 see e.g.: https://www.dsprelated.com/freebooks/filters/Four_Direct_Forms.html
altb2 0:a201a6cd4c0c 4 everything is calculated in double
altb2 0:a201a6cd4c0c 5
altb2 0:a201a6cd4c0c 6 Tn*s + 1
altb2 0:a201a6cd4c0c 7 G(s) = Kp ------------- with s ~ (1 - z^-1)/Ts
altb2 0:a201a6cd4c0c 8 Ts*s
altb2 0:a201a6cd4c0c 9 */
altb2 0:a201a6cd4c0c 10
altb2 0:a201a6cd4c0c 11 #include "PI_Cntrl.h"
altb2 0:a201a6cd4c0c 12
altb2 0:a201a6cd4c0c 13 using namespace std;
altb2 0:a201a6cd4c0c 14
altb2 0:a201a6cd4c0c 15 PI_Cntrl::PI_Cntrl(float Kp, float Tn, float Ts)
altb2 0:a201a6cd4c0c 16 {
altb2 0:a201a6cd4c0c 17 setCoefficients(Kp, Tn, Ts);
altb2 0:a201a6cd4c0c 18 uMax = 10000000000.0;
altb2 0:a201a6cd4c0c 19 uMin = -uMax;
altb2 0:a201a6cd4c0c 20 reset(0.0f);
altb2 0:a201a6cd4c0c 21 }
altb2 0:a201a6cd4c0c 22
altb2 0:a201a6cd4c0c 23 PI_Cntrl::PI_Cntrl(float Kp, float Tn, float Ts, float uMax)
altb2 0:a201a6cd4c0c 24 {
altb2 0:a201a6cd4c0c 25 setCoefficients(Kp, Tn, Ts);
altb2 0:a201a6cd4c0c 26 this->uMax = (double)uMax;
altb2 0:a201a6cd4c0c 27 uMin = -(double)uMax;
altb2 0:a201a6cd4c0c 28 reset(0.0f);
altb2 0:a201a6cd4c0c 29 }
altb2 0:a201a6cd4c0c 30
altb2 0:a201a6cd4c0c 31 PI_Cntrl::PI_Cntrl(float Kp, float Tn, float Ts, float uMax, float uMin)
altb2 0:a201a6cd4c0c 32 {
altb2 0:a201a6cd4c0c 33 setCoefficients(Kp, Tn, Ts);
altb2 0:a201a6cd4c0c 34 this->uMax = (double)uMax;
altb2 0:a201a6cd4c0c 35 this->uMin = (double)uMin;
altb2 0:a201a6cd4c0c 36 reset(0.0f);
altb2 0:a201a6cd4c0c 37 }
altb2 0:a201a6cd4c0c 38
altb2 0:a201a6cd4c0c 39 PI_Cntrl::~PI_Cntrl() {}
altb2 0:a201a6cd4c0c 40
altb2 0:a201a6cd4c0c 41 void PI_Cntrl::reset(float initValue)
altb2 0:a201a6cd4c0c 42 {
altb2 0:a201a6cd4c0c 43 s = (double)initValue;
altb2 0:a201a6cd4c0c 44 }
altb2 0:a201a6cd4c0c 45
altb2 0:a201a6cd4c0c 46 void PI_Cntrl::setCoefficients(float Kp, float Tn, float Ts)
altb2 0:a201a6cd4c0c 47 {
altb2 0:a201a6cd4c0c 48 b0 = (double)Kp*(1.0 + (double)Ts/(double)Tn);
altb2 0:a201a6cd4c0c 49 b1 = -(double)Kp;
altb2 0:a201a6cd4c0c 50 b2 = (double)Ts/(double)Tn;
altb2 0:a201a6cd4c0c 51 }
altb2 0:a201a6cd4c0c 52
altb2 0:a201a6cd4c0c 53 float PI_Cntrl::doStep(double e)
altb2 0:a201a6cd4c0c 54 {
altb2 0:a201a6cd4c0c 55 double u = b0*e + s; // unconstrained output
altb2 0:a201a6cd4c0c 56 double uc = u; // constrained output
altb2 0:a201a6cd4c0c 57 if(u > uMax) uc = uMax;
altb2 0:a201a6cd4c0c 58 else if(u < uMin) uc = uMin;
altb2 0:a201a6cd4c0c 59 s = b1*e + u - b2*(u - uc);
altb2 0:a201a6cd4c0c 60 return (float)uc;
altb2 0:a201a6cd4c0c 61 }