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111 lines
3.5 KiB
111 lines
3.5 KiB
// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*- |
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/// @file AC_HELI_PID.cpp |
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/// @brief Generic PID algorithm |
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#include <AP_Math/AP_Math.h> |
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#include "AC_HELI_PID.h" |
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const AP_Param::GroupInfo AC_HELI_PID::var_info[] = { |
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// @Param: P |
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// @DisplayName: PID Proportional Gain |
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// @Description: P Gain which produces an output value that is proportional to the current error value |
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AP_GROUPINFO("P", 0, AC_HELI_PID, _kp, 0), |
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// @Param: I |
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// @DisplayName: PID Integral Gain |
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// @Description: I Gain which produces an output that is proportional to both the magnitude and the duration of the error |
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AP_GROUPINFO("I", 1, AC_HELI_PID, _ki, 0), |
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// @Param: D |
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// @DisplayName: PID Derivative Gain |
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// @Description: D Gain which produces an output that is proportional to the rate of change of the error |
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AP_GROUPINFO("D", 2, AC_HELI_PID, _kd, 0), |
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// @Param: VFF |
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// @DisplayName: Velocity FF FeedForward Gain |
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// @Description: Velocity FF Gain which produces an output value that is proportional to the demanded input |
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AP_GROUPINFO("VFF", 4, AC_HELI_PID, _vff, 0), |
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// @Param: IMAX |
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// @DisplayName: PID Integral Maximum |
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// @Description: The maximum/minimum value that the I term can output |
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AP_GROUPINFO("IMAX", 5, AC_HELI_PID, _imax, 0), |
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// @Param: FILT_HZ |
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// @DisplayName: PID Input filter frequency in Hz |
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// @Description: |
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AP_GROUPINFO("FILT_HZ", 6, AC_HELI_PID, _filt_hz, AC_PID_FILT_HZ_DEFAULT), |
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// @Param: I_L_MIN |
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// @DisplayName: I-term Leak Minimum |
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// @Description: Point below which I-term will not leak down |
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// @Range: 0 4500 |
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// @User: Advanced |
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AP_GROUPINFO("I_L_MIN", 7, AC_HELI_PID, _leak_min, AC_PID_LEAK_MIN), |
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// @Param: AFF |
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// @DisplayName: Acceleration FF FeedForward Gain |
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// @Description: Acceleration FF Gain which produces an output value that is proportional to the change in demanded input |
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AP_GROUPINFO("AFF", 8, AC_HELI_PID, _aff, 0), |
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AP_GROUPEND |
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}; |
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/// Constructor for PID |
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AC_HELI_PID::AC_HELI_PID(float initial_p, float initial_i, float initial_d, float initial_imax, float initial_filt_hz, float dt, float initial_vff) : |
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AC_PID(initial_p, initial_i, initial_d, initial_imax, initial_filt_hz, dt) |
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{ |
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_vff = initial_vff; |
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_aff = 0; |
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_last_requested_rate = 0; |
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} |
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float AC_HELI_PID::get_vff(float requested_rate) |
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{ |
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_pid_info.FF = (float)requested_rate * _vff; |
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return _pid_info.FF; |
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} |
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float AC_HELI_PID::get_aff(float requested_rate) |
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{ |
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float derivative; |
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// calculate derivative |
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if (_dt > 0.0f) { |
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derivative = (requested_rate - _last_requested_rate) / _dt; |
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} else { |
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derivative = 0; |
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} |
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_pid_info.AFF = derivative * _aff; |
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_last_requested_rate = requested_rate; |
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return _pid_info.AFF; |
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} |
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// This is an integrator which tends to decay to zero naturally |
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// if the error is zero. |
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float AC_HELI_PID::get_leaky_i(float leak_rate) |
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{ |
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if(!is_zero(_ki) && !is_zero(_dt)){ |
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// integrator does not leak down below Leak Min |
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if (_integrator > _leak_min){ |
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_integrator -= (float)(_integrator - _leak_min) * leak_rate; |
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} else if (_integrator < -_leak_min) { |
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_integrator -= (float)(_integrator + _leak_min) * leak_rate; |
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} |
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_integrator += ((float)_input * _ki) * _dt; |
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if (_integrator < -_imax) { |
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_integrator = -_imax; |
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} else if (_integrator > _imax) { |
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_integrator = _imax; |
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} |
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_pid_info.I = _integrator; |
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return _integrator; |
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} |
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return 0; |
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}
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