Doug Weibel 2bb1d17c7e Changes to the PID controller. Adds "limit" to the parameter set. Implements an output limit where the output magnitude is limited by the parameter value "limit". Also changes the integrator saturation such that the integrator is not updated (added to) if either updating it will cause the integrator values magnitude to exceed "intmax" or if the output magnitude would exceed "limit" with an updated integrator value.
Arbitrary large limit values were hard coded into multirotor_attitude_control.c.  These should be changed to parametric values or something sensible.

This commit will temporarily break fixedwing_control.c.  A following commit will repair it along with significant changes to the inner loop control.

This commit has been tested to compile with fixedwing_control.c temporarily removed.  No other testing has been completed.
2012-10-07 14:46:26 -06:00

78 lines
2.9 KiB
C

/****************************************************************************
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* Copyright (C) 2008-2012 PX4 Development Team. All rights reserved.
* Author: @author Laurens Mackay <mackayl@student.ethz.ch>
* @author Tobias Naegeli <naegelit@student.ethz.ch>
* @author Martin Rutschmann <rutmarti@student.ethz.ch>
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/**
* @file pid.h
* Definition of generic PID control interface
*/
#ifndef PID_H_
#define PID_H_
#include <stdint.h>
/* PID_MODE_DERIVATIV_CALC calculates discrete derivative from previous error
* val_dot in pid_calculate() will be ignored */
#define PID_MODE_DERIVATIV_CALC 0
/* Use PID_MODE_DERIVATIV_SET if you have the derivative already (Gyros, Kalman) */
#define PID_MODE_DERIVATIV_SET 1
// Use PID_MODE_DERIVATIV_NONE for a PI controller (vs PID)
#define PID_MODE_DERIVATIV_NONE 9
typedef struct {
float kp;
float ki;
float kd;
float intmax;
float sp;
float integral;
float error_previous;
float last_output;
float limit;
uint8_t mode;
uint8_t count;
uint8_t saturated;
} PID_t;
__EXPORT void pid_init(PID_t *pid, float kp, float ki, float kd, float intmax, float limit, uint8_t mode);
__EXPORT int pid_set_parameters(PID_t *pid, float kp, float ki, float kd, float intmax, float limit);
//void pid_set(PID_t *pid, float sp);
__EXPORT float pid_calculate(PID_t *pid, float sp, float val, float val_dot, float dt);
#endif /* PID_H_ */