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Fork of Cntrlol_Lib by
PID_Cntrl.cpp
- Committer:
- altb
- Date:
- 2018-09-28
- Revision:
- 1:bf62e74fbcf3
- Parent:
- 0:e2a7d7f91e49
- Child:
- 2:1f8ddc46c578
File content as of revision 1:bf62e74fbcf3:
/* PI Controller class with anti windup reset in biquad transposed direct form 2 see e.g.: https://www.dsprelated.com/freebooks/filters/Four_Direct_Forms.html everything is calculated in double Ts z - 1 G(s) = P + I ------- + D ------- z - 1 z - p */ #include "PID_Cntrl.h" using namespace std; PID_Cntrl::PID_Cntrl(float P, float I, float D, float tau_f, float Ts, float uMax, float uMin) { setCoefficients(P, I, D, tau_f, Ts); this->uMax = (double)uMax; this->uMin = (double)uMin; reset(0.0f); } PID_Cntrl::~PID_Cntrl() {} void PID_Cntrl::reset(float initValue) { Iold = (double)initValue; eold = 0.0;yold = 0.0; del = 0.0; } void PID_Cntrl::setCoefficients(float P, float I, float D, float tau_f, float Ts) { this->p = 1.0 - (double)Ts/(double)tau_f; this->P = P; this->I = I; this->D = D; } float PID_Cntrl::doStep(double e) { double u = P*e + D*(e-eold)+p*yold +Iold+I*Ts*(e-del); // unconstrained output double uc = u; // constrained output if(u > uMax) uc = uMax; else if(u < uMin) uc = uMin; del=(u-uc)/P; return (float)uc; }