ardupilot/libraries/AC_PID/AC_HELI_PID.cpp

99 lines
3.8 KiB
C++

/// @file AC_HELI_PID.cpp
/// @brief Generic PID algorithm
#include <AP_Math/AP_Math.h>
#include "AC_HELI_PID.h"
const AP_Param::GroupInfo AC_HELI_PID::var_info[] = {
// @Param: P
// @DisplayName: PID Proportional Gain
// @Description: P Gain which produces an output value that is proportional to the current error value
AP_GROUPINFO("P", 0, AC_HELI_PID, _kp, 0),
// @Param: I
// @DisplayName: PID Integral Gain
// @Description: I Gain which produces an output that is proportional to both the magnitude and the duration of the error
AP_GROUPINFO("I", 1, AC_HELI_PID, _ki, 0),
// @Param: D
// @DisplayName: PID Derivative Gain
// @Description: D Gain which produces an output that is proportional to the rate of change of the error
AP_GROUPINFO("D", 2, AC_HELI_PID, _kd, 0),
// 3 was for uint16 IMAX
// @Param: VFF
// @DisplayName: Velocity FF FeedForward Gain
// @Description: Velocity FF Gain which produces an output value that is proportional to the demanded input
AP_GROUPINFO("VFF", 4, AC_HELI_PID, _kff, 0),
// @Param: IMAX
// @DisplayName: PID Integral Maximum
// @Description: The maximum/minimum value that the I term can output
AP_GROUPINFO("IMAX", 5, AC_HELI_PID, _kimax, 0),
// 6 was for float FILT
// @Param: ILMI
// @DisplayName: I-term Leak Minimum
// @Description: Point below which I-term will not leak down
// @Range: 0 1
// @User: Advanced
AP_GROUPINFO("ILMI", 7, AC_HELI_PID, _leak_min, AC_PID_LEAK_MIN),
// 8 was for float AFF
// @Param: FLTT
// @DisplayName: PID Target filter frequency in Hz
// @Description: Target filter frequency in Hz
// @Units: Hz
AP_GROUPINFO("FLTT", 9, AC_HELI_PID, _filt_T_hz, AC_PID_TFILT_HZ_DEFAULT),
// @Param: FLTE
// @DisplayName: PID Error filter frequency in Hz
// @Description: Error filter frequency in Hz
// @Units: Hz
AP_GROUPINFO("FLTE", 10, AC_HELI_PID, _filt_E_hz, AC_PID_EFILT_HZ_DEFAULT),
// @Param: FLTD
// @DisplayName: PID D term filter frequency in Hz
// @Description: Derivative filter frequency in Hz
// @Units: Hz
AP_GROUPINFO("FLTD", 11, AC_HELI_PID, _filt_D_hz, AC_PID_DFILT_HZ_DEFAULT),
// @Param: SMAX
// @DisplayName: Slew rate limit
// @Description: Sets an upper limit on the slew rate produced by the combined P and D gains. If the amplitude of the control action produced by the rate feedback exceeds this value, then the D+P gain is reduced to respect the limit. This limits the amplitude of high frequency oscillations caused by an excessive gain. The limit should be set to no more than 25% of the actuators maximum slew rate to allow for load effects. Note: The gain will not be reduced to less than 10% of the nominal value. A value of zero will disable this feature.
// @Range: 0 200
// @Increment: 0.5
// @User: Advanced
AP_GROUPINFO("SMAX", 12, AC_HELI_PID, _slew_rate_max, 0),
AP_GROUPEND
};
/// Constructor for PID
AC_HELI_PID::AC_HELI_PID(float initial_p, float initial_i, float initial_d, float initial_ff, float initial_imax, float initial_filt_T_hz, float initial_filt_E_hz, float initial_filt_D_hz, float dt) :
AC_PID(initial_p, initial_i, initial_d, initial_ff, initial_imax, initial_filt_T_hz, initial_filt_E_hz, initial_filt_D_hz, dt)
{
_last_requested_rate = 0;
}
// This is an integrator which tends to decay to zero naturally
// if the error is zero.
void AC_HELI_PID::update_leaky_i(float leak_rate)
{
if(!is_zero(_ki) && !is_zero(_dt)){
// integrator does not leak down below Leak Min
if (_integrator > _leak_min){
_integrator -= (float)(_integrator - _leak_min) * leak_rate;
} else if (_integrator < -_leak_min) {
_integrator -= (float)(_integrator + _leak_min) * leak_rate;
}
_pid_info.I = _integrator;
}
}