altb_pmic / Lib_Cntrl

Control Library by altb

Dependents:   My_Libraries IndNav_QK3_T265

PID_Cntrl.cpp@2:e7c9e50a2e46, 2019-06-14 (annotated)

Committer:
altb2
Date:
Fri Jun 14 07:05:55 2019 +0000
Revision:
2:e7c9e50a2e46
Parent:
0:d49418189c5c
Child:
3:27595dd9e433
Changed D-Part, it is now consistent with Matlab (pid)

Who changed what in which revision?

UserRevisionLine numberNew contents of line
altb 0:d49418189c5c 1 /*
altb 0:d49418189c5c 2 PI Controller class with anti windup reset in biquad transposed direct form 2
altb 0:d49418189c5c 3 see e.g.: https://www.dsprelated.com/freebooks/filters/Four_Direct_Forms.html
altb2 2:e7c9e50a2e46 4 everything is calculated in float
altb 0:d49418189c5c 5
altb2 2:e7c9e50a2e46 6 Ts z - 1
altb2 2:e7c9e50a2e46 7 G(s) = P + I ------- + D/tau ------- D corresponds Kd in Matlab-formlism pid(...)
altb2 2:e7c9e50a2e46 8 z - 1 z - p
altb 0:d49418189c5c 9 */
altb 0:d49418189c5c 10
altb 0:d49418189c5c 11 #include "PID_Cntrl.h"
altb 0:d49418189c5c 12 using namespace std;
altb 0:d49418189c5c 13
altb 0:d49418189c5c 14 PID_Cntrl::PID_Cntrl(float P, float I, float D, float tau_f, float Ts, float uMin, float uMax)
altb 0:d49418189c5c 15 {
altb 0:d49418189c5c 16 setCoefficients(P, I, D, tau_f, Ts);
altb2 2:e7c9e50a2e46 17 this->uMin = uMin;
altb2 2:e7c9e50a2e46 18 this->uMax = uMax;
altb 0:d49418189c5c 19 reset(0.0f);
altb 0:d49418189c5c 20 }
altb 0:d49418189c5c 21
altb 0:d49418189c5c 22 PID_Cntrl::~PID_Cntrl() {}
altb 0:d49418189c5c 23
altb 0:d49418189c5c 24 void PID_Cntrl::reset(float initValue)
altb 0:d49418189c5c 25 {
altb2 2:e7c9e50a2e46 26 Iold = initValue;
altb 0:d49418189c5c 27 eold = 0.0;yold = 0.0;
altb 0:d49418189c5c 28 del = 0.0;
altb 0:d49418189c5c 29 }
altb 0:d49418189c5c 30
altb 0:d49418189c5c 31 void PID_Cntrl::setCoefficients(float P, float I, float D, float tau_f, float Ts)
altb 0:d49418189c5c 32 {
altb2 2:e7c9e50a2e46 33 this->p = 1.0 - Ts/tau_f;
altb 0:d49418189c5c 34 this->P = P;
altb 0:d49418189c5c 35 this->I = I;
altb2 2:e7c9e50a2e46 36 this->D_ = D/tau_f; // modified D, now D is consistent with Matlab PID
altb 0:d49418189c5c 37 this->Ts = Ts;
altb 0:d49418189c5c 38 if(P!=0)
altb 0:d49418189c5c 39 this->Ka=1/P;
altb 0:d49418189c5c 40 else
altb 0:d49418189c5c 41 this->Ka=1.0f;
altb 0:d49418189c5c 42
altb 0:d49418189c5c 43 }
altb 0:d49418189c5c 44
altb2 2:e7c9e50a2e46 45 float PID_Cntrl::doStep(float e)
altb 0:d49418189c5c 46 {
altb2 2:e7c9e50a2e46 47 float Ipart = Iold+I*Ts*(e-del);
altb2 2:e7c9e50a2e46 48 float Dpart = D_*(e-eold)+p*yold;
altb2 2:e7c9e50a2e46 49 float u = P*e + Dpart + Ipart; // unconstrained output
altb2 2:e7c9e50a2e46 50 float uc = u; // constrained output
altb 0:d49418189c5c 51 if(u > uMax) uc = uMax;
altb 0:d49418189c5c 52 else if(u < uMin) uc = uMin;
altb 0:d49418189c5c 53 del=(u-uc)*Ka;
altb 0:d49418189c5c 54 eold=e;
altb 0:d49418189c5c 55 Iold=Ipart;
altb 0:d49418189c5c 56 yold=Dpart;
altb2 2:e7c9e50a2e46 57 return uc;
altb 0:d49418189c5c 58 }
altb 0:d49418189c5c 59
altb2 2:e7c9e50a2e46 60 void PID_Cntrl::set_limits(float ll, float ul)
altb 0:d49418189c5c 61 {
altb2 2:e7c9e50a2e46 62 this->uMin = ll;
altb2 2:e7c9e50a2e46 63 this->uMax = ul;
altb 0:d49418189c5c 64 }
altb 0:d49418189c5c 65
altb 0:d49418189c5c 66 float PID_Cntrl::get_ulimit(void)
altb 0:d49418189c5c 67 {
altb2 2:e7c9e50a2e46 68 return this->uMax;
altb 0:d49418189c5c 69 }