ardupilot/libraries/AC_PID/AC_PID.h

111 lines
3.8 KiB
C++

#pragma once
/// @file AC_PID.h
/// @brief Generic PID algorithm, with EEPROM-backed storage of constants.
#include <AP_Common/AP_Common.h>
#include <AP_Param/AP_Param.h>
#include <stdlib.h>
#include <cmath>
#include <DataFlash/DataFlash.h>
#define AC_PID_FILT_HZ_DEFAULT 20.0f // default input filter frequency
#define AC_PID_FILT_HZ_MIN 0.01f // minimum input filter frequency
/// @class AC_PID
/// @brief Copter PID control class
class AC_PID {
public:
// Constructor for PID
AC_PID(float initial_p, float initial_i, float initial_d, float initial_imax, float initial_filt_hz, float dt, float initial_ff = 0);
// set_dt - set time step in seconds
void set_dt(float dt);
// set_input_filter_all - set input to PID controller
// input is filtered before the PID controllers are run
// this should be called before any other calls to get_p, get_i or get_d
void set_input_filter_all(float input);
// set_input_filter_d - set input to PID controller
// only input to the D portion of the controller is filtered
// this should be called before any other calls to get_p, get_i or get_d
void set_input_filter_d(float input);
// get_pid - get results from pid controller
float get_pid();
float get_pi();
float get_p();
float get_i();
float get_d();
float get_ff(float requested_rate);
// reset_I - reset the integrator
void reset_I();
// reset_filter - input filter will be reset to the next value provided to set_input()
void reset_filter() { _flags._reset_filter = true; }
// load gain from eeprom
void load_gains();
// save gain to eeprom
void save_gains();
/// operator function call for easy initialisation
void operator() (float p, float i, float d, float imaxval, float input_filt_hz, float dt, float ffval = 0);
// get accessors
AP_Float &kP() { return _kp; }
AP_Float &kI() { return _ki; }
AP_Float &kD() { return _kd; }
AP_Float &filt_hz() { return _filt_hz; }
float imax() const { return _imax.get(); }
float get_filt_alpha() const;
float ff() const { return _ff.get(); }
// set accessors
void kP(const float v) { _kp.set(v); }
void kI(const float v) { _ki.set(v); }
void kD(const float v) { _kd.set(v); }
void imax(const float v) { _imax.set(fabsf(v)); }
void filt_hz(const float v);
void ff(const float v) { _ff.set(v); }
float get_integrator() const { return _integrator; }
void set_integrator(float i) { _integrator = i; }
// set the desired and actual rates (for logging purposes)
void set_desired_rate(float desired) { _pid_info.desired = desired; }
void set_actual_rate(float actual) { _pid_info.actual = actual; }
const DataFlash_Class::PID_Info& get_pid_info(void) const { return _pid_info; }
// parameter var table
static const struct AP_Param::GroupInfo var_info[];
protected:
// parameters
AP_Float _kp;
AP_Float _ki;
AP_Float _kd;
AP_Float _imax;
AP_Float _filt_hz; // PID Input filter frequency in Hz
AP_Float _ff;
// flags
struct ac_pid_flags {
bool _reset_filter : 1; // true when input filter should be reset during next call to set_input
} _flags;
// internal variables
float _dt; // timestep in seconds
float _integrator; // integrator value
float _input; // last input for derivative
float _derivative; // last derivative for low-pass filter
DataFlash_Class::PID_Info _pid_info;
};