IPFFController.c

Go to the documentation of this file.

/*********************************************************************
* Software License Agreement (BSD License)
*
*  Copyright (c) 2010, LABUST, UNIZG-FER
*  All rights reserved.
*
*  Redistribution and use in source and binary forms, with or without
*  modification, are permitted provided that the following conditions
*  are met:
*
*   * Redistributions of source code must retain the above copyright
*     notice, this list of conditions and the following disclaimer.
*   * Redistributions in binary form must reproduce the above
*     copyright notice, this list of conditions and the following
*     disclaimer in the documentation and/or other materials provided
*     with the distribution.
*   * Neither the name of the LABUST nor the names of its
*     contributors may be used to endorse or promote products derived
*     from this software without specific prior written permission.
*
*  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
*  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
*  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
*  FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
*  COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
*  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
*  BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
*  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
*  CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
*  LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
*  ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
*  POSSIBILITY OF SUCH DAMAGE.
*********************************************************************/
#include <labust/control/IPFFController.h>
#include <math.h>

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

void IPFF_wffStep(PIDBase* self, float Ts, float error, float ff)
{
        //Perform windup test if automatic mode is enabled.
        if (self->autoWindup == 1)
        {
                self->track = self->output;
                self->windup = (self->internalState != self->track) && (error*self->track > 0);
        }
        else
        {
                //Experimental
                self->windup = (self->extWindup && (error*self->output > 0));
        }

        //Backward recalculation
        if ((self->lastI != 0) && self->windup && self->useBackward)
        {
                //Calculate the proportional influence
                float diff = self->track - self->internalState + self->lastI;
                //If the proportional part is already in windup remove the whole last integral
                //Otherwise recalculate the integral to be on the edge of windup
                self->internalState -= ((diff*self->track <= 0)?self->lastI:(self->lastI - diff));
        }

        //Proportional term
        self->internalState -= self->Kp*(self->state-self->lastState);
        //Integral term
        //Disabled if windup is in progress.
        if (!self->windup) self->internalState += (self->lastI = self->Ki*Ts*error);
        else self->lastI = 0;
        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;
        self->lastState = self->state;
}