pid.h

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/*
 * 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; either version 3 of the License, or
 * (at your option) any later version.
 *
 * 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, see <http://www.gnu.org/licenses/>
 */

#ifndef PID_H
#define PID_H

struct pid_deadband {
        float width;                            // Deadband width in degrees per second.
        float slope;                            // Deadband slope (0..1).
        float cubic_weight;                     // Cubic weight.
        float integrated_response;      // Response at deadband edge.
};

struct pid {
        float p;
        float i;
        float d;
        float iLim;

        float dT;

        float iAccumulator;
        float lastErr;
        float lastDer;
};

float pid_apply(struct pid *pid, const float err);
float pid_apply_antiwindup(struct pid *pid, const float err, float min_bound, float max_bound, float aw_bound);
float pid_apply_setpoint(struct pid *pid, struct pid_deadband *deadband, const float setpoint, const float measured);
float pid_apply_setpoint_antiwindup(struct pid *pid,
                struct pid_deadband *deadband, const float setpoint,
                const float measured, float min_bound, float max_bound, float aw_bound);
void pid_zero(struct pid *pid);
void pid_configure(struct pid *pid, float p, float i, float d, float iLim, float dT);
void pid_configure_derivative(float cutoff, float gamma);
void pid_configure_deadband(struct pid_deadband *deadband, float width, float slope);


#endif /* PID_H */