mirror of https://github.com/ArduPilot/ardupilot
130 lines
3.3 KiB
C++
130 lines
3.3 KiB
C++
/// @file PID.h
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/// @brief Generic PID algorithm, with EEPROM-backed storage of constants.
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#pragma once
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#include <AP_Common/AP_Common.h>
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#include <AP_Param/AP_Param.h>
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#include <AC_PID/AC_PID.h> // for AP_PIDInfo
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#include <stdlib.h>
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#include <cmath>
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/// @class PID
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/// @brief Object managing one PID control
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class PID {
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public:
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PID(const float & initial_p = 0.0f,
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const float & initial_i = 0.0f,
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const float & initial_d = 0.0f,
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const int16_t & initial_imax = 0):
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default_kp(initial_p),
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default_ki(initial_i),
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default_kd(initial_d),
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default_kimax(initial_imax)
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{
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AP_Param::setup_object_defaults(this, var_info);
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// set _last_derivative as invalid when we startup
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_last_derivative = NAN;
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}
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/// Iterate the PID, return the new control value
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///
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/// Positive error produces positive output.
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///
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/// @param error The measured error value
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/// @param scaler An arbitrary scale factor
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///
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/// @returns The updated control output.
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///
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float get_pid(float error, float scaler = 1.0);
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/// Reset the whole PID state
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//
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void reset();
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/// Reset the PID integrator
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///
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void reset_I();
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/// Load gain properties
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///
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void load_gains();
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/// Save gain properties
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///
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void save_gains();
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/// @name parameter accessors
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//@{
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/// Overload the function call operator to permit relatively easy initialisation
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void operator () (const float p,
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const float i,
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const float d,
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const int16_t imaxval) {
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_kp.set(p); _ki.set(i); _kd.set(d); _imax.set(imaxval);
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}
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float kP() const {
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return _kp.get();
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}
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float kI() const {
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return _ki.get();
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}
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float kD() const {
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return _kd.get();
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}
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int16_t imax() const {
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return _imax.get();
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}
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void kP(const float v) {
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_kp.set(v);
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}
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void kI(const float v) {
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_ki.set(v);
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}
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void kD(const float v) {
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_kd.set(v);
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}
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void imax(const int16_t v) {
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_imax.set(abs(v));
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}
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float get_integrator() const {
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return _integrator;
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}
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static const struct AP_Param::GroupInfo var_info[];
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const AP_PIDInfo& get_pid_info(void) const { return _pid_info; }
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private:
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AP_Float _kp;
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AP_Float _ki;
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AP_Float _kd;
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AP_Int16 _imax;
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float _integrator;///< integrator value
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float _last_error;///< last error for derivative
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float _last_derivative;///< last derivative for low-pass filter
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uint32_t _last_t;///< last time get_pid() was called in millis
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float _get_pid(float error, uint16_t dt, float scaler);
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AP_PIDInfo _pid_info {};
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/// Low pass filter cut frequency for derivative calculation.
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///
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/// 20 Hz because anything over that is probably noise, see
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/// http://en.wikipedia.org/wiki/Low-pass_filter.
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///
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static const uint8_t _fCut = 20;
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const float default_kp;
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const float default_ki;
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const float default_kd;
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const float default_kimax;
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};
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