PIFFController.c

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#include <labust/control/PIFFController.h>
#include <math.h>

void PIFF_modelTune(PIDBase* self,
                const PT1Model* const model,
                float w)
{
        self->Kp = 2*w*model->alpha-model->beta;
        self->Ki = model->alpha*w*w;
        self->Kd = self->Kt = self->Tf = 0;

        self->model.alpha = model->alpha;
        self->model.beta = model->beta;
        self->model.betaa = model->betaa;
}

void PIFF_tune(PIDBase* self, float w)
{
        self->Kp = 2*w;
        self->Ki = w*w;
        self->Kd = self->Kt = self->Tf = 0;
}

void PIFF_wffStep(PIDBase* self, float Ts, float error, float ff)
{
        //Perform windup test if automatic mode is enabled.
        if (self->autoWindup == 1)
        {
                self->windup = (self->internalState > self->output) && (error>0);
                self->windup = (self->windup) ||
                                ((self->internalState < self->output) && (error<0));
                //Set the wind-up sign for cascade controllers.
                if ((self->windup) && (self->internalState < self->output))     self->windup = -1;
        }
        else
        {
                //Experimental
                self->windup = ((self->windup > 0) && (error > 0)) ||
                                ((self->windup < 0) && (error < 0));
        }

        //Proportional term
        self->internalState += self->Kp*(error-self->lastError);
        //Integral term
        //Disabled if windup is in progress.
  if (!self->windup) self->internalState += self->Ki*Ts*error;
        //Feed forward term
        self->internalState += ff - self->lastFF;
        //Set final output
        self->output = self->internalState;

        if (self->autoWindup == 1)
        {
                self->output = sat(self->output,-self->outputLimit, self->outputLimit);
        }

        self->lastError = error;
        self->lastRef = self->desired;
        self->lastFF = ff;
}