sam7fc/src/pidctrl.c

/***************************************************************************
 *   Copyright (C) 03/2008 by Olaf Rempel                                  *
 *   razzor@kopf-tisch.de                                                  *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; version 2 of the License                *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/
#include <stdint.h>

#include "pidctrl.h"
#include "board.h"

int32_t pid_ctrl(struct pid_data *pid, int32_t error)
{
	int32_t out = 0;

	if (pid->kp != 0)
		out += pid->kp * error;

	if (pid->ki != 0) {
		pid->err_sum += error;
		pid->err_sum = LIMIT(pid->err_sum, pid->err_sum_min, pid->err_sum_max);

		out += (pid->err_sum / pid->ki);
	}

	if (pid->kd != 0) {
		out += pid->kd * (error - pid->err_old);
		pid->err_old = error;
	}

	return LIMIT(out, pid->out_min, pid->out_max);
}