altb_pmic / Lib_Cntrl

Control Library by altb

Dependents:   My_Libraries IndNav_QK3_T265

PID_Cntrl.cpp@5:d8c53cece01b, 2019-08-26 (annotated)

Committer:
altb2
Date:
Mon Aug 26 07:07:02 2019 +0000
Revision:
5:d8c53cece01b
Parent:
3:27595dd9e433
Child:
10:447f6a864598
Added "Safe" parameters P,I,D to scale

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;
altb2 5:d8c53cece01b 35 this->P_init = P;
altb 0:d49418189c5c 36 this->I = I;
altb2 5:d8c53cece01b 37 this->I_init = I;
altb2 3:27595dd9e433 38 this->tau_f = tau_f;
altb2 2:e7c9e50a2e46 39 this->D_ = D/tau_f; // modified D, now D is consistent with Matlab PID
altb2 5:d8c53cece01b 40 this->D__init = D/tau_f; // modified D, now D is consistent with Matlab PID
altb 0:d49418189c5c 41 this->Ts = Ts;
altb 0:d49418189c5c 42 if(P!=0)
altb 0:d49418189c5c 43 this->Ka=1/P;
altb 0:d49418189c5c 44 else
altb 0:d49418189c5c 45 this->Ka=1.0f;
altb 0:d49418189c5c 46
altb 0:d49418189c5c 47 }
altb2 3:27595dd9e433 48 void PID_Cntrl::setCoeff_P(float P)
altb2 3:27595dd9e433 49 {
altb2 3:27595dd9e433 50 this->P = P;
altb2 3:27595dd9e433 51 }
altb2 3:27595dd9e433 52 void PID_Cntrl::setCoeff_I(float I)
altb2 3:27595dd9e433 53 {
altb2 3:27595dd9e433 54 this->I = I;
altb2 3:27595dd9e433 55 }
altb2 3:27595dd9e433 56 void PID_Cntrl::setCoeff_D(float D)
altb2 3:27595dd9e433 57 {
altb2 3:27595dd9e433 58 this->D_ = D/this->tau_f;
altb2 3:27595dd9e433 59 }
altb2 5:d8c53cece01b 60 void PID_Cntrl::scale_PID_param(float sc)
altb2 5:d8c53cece01b 61 {
altb2 5:d8c53cece01b 62 this->P = this->P_init * sc;
altb2 5:d8c53cece01b 63 this->I = this->I_init * sc;
altb2 5:d8c53cece01b 64 this->D_ = this->D__init * sc;
altb2 5:d8c53cece01b 65 }
altb 0:d49418189c5c 66
altb2 2:e7c9e50a2e46 67 float PID_Cntrl::doStep(float e)
altb 0:d49418189c5c 68 {
altb2 2:e7c9e50a2e46 69 float Ipart = Iold+I*Ts*(e-del);
altb2 2:e7c9e50a2e46 70 float Dpart = D_*(e-eold)+p*yold;
altb2 2:e7c9e50a2e46 71 float u = P*e + Dpart + Ipart; // unconstrained output
altb2 2:e7c9e50a2e46 72 float uc = u; // constrained output
altb 0:d49418189c5c 73 if(u > uMax) uc = uMax;
altb 0:d49418189c5c 74 else if(u < uMin) uc = uMin;
altb 0:d49418189c5c 75 del=(u-uc)*Ka;
altb 0:d49418189c5c 76 eold=e;
altb 0:d49418189c5c 77 Iold=Ipart;
altb 0:d49418189c5c 78 yold=Dpart;
altb2 2:e7c9e50a2e46 79 return uc;
altb 0:d49418189c5c 80 }
altb 0:d49418189c5c 81
altb2 2:e7c9e50a2e46 82 void PID_Cntrl::set_limits(float ll, float ul)
altb 0:d49418189c5c 83 {
altb2 2:e7c9e50a2e46 84 this->uMin = ll;
altb2 2:e7c9e50a2e46 85 this->uMax = ul;
altb 0:d49418189c5c 86 }
altb 0:d49418189c5c 87
altb 0:d49418189c5c 88 float PID_Cntrl::get_ulimit(void)
altb 0:d49418189c5c 89 {
altb2 2:e7c9e50a2e46 90 return this->uMax;
altb2 5:d8c53cece01b 91 }
altb2 5:d8c53cece01b 92
altb2 5:d8c53cece01b 93 float PID_Cntrl::get_P_gain(void)
altb2 5:d8c53cece01b 94 {
altb2 5:d8c53cece01b 95 return this->P;
altb 0:d49418189c5c 96 }