mirror of https://github.com/ArduPilot/ardupilot
97 lines
3.0 KiB
C++
97 lines
3.0 KiB
C++
/// @file AC_P_1D.cpp
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/// @brief Generic P algorithm
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#include <AP_Math/AP_Math.h>
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#include "AC_P_1D.h"
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const AP_Param::GroupInfo AC_P_1D::var_info[] = {
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// @Param: P
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// @DisplayName: P 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_P_1D, _kp, 0),
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AP_GROUPEND
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};
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// Constructor
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AC_P_1D::AC_P_1D(float initial_p, float dt) :
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_dt(dt)
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{
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// load parameter values from eeprom
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AP_Param::setup_object_defaults(this, var_info);
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_kp = initial_p;
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}
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// update_all - set target and measured inputs to P controller and calculate outputs
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// target and measurement are filtered
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// if measurement is further than error_min or error_max (see set_limits method)
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// the target is moved closer to the measurement and limit_min or limit_max will be set true
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float AC_P_1D::update_all(float &target, float measurement, bool &limit_min, bool &limit_max)
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{
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limit_min = false;
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limit_max = false;
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// calculate distance _error
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_error = target - measurement;
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if (is_negative(_error_min) && (_error < _error_min)) {
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_error = _error_min;
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target = measurement + _error;
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limit_min = true;
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} else if (is_positive(_error_max) && (_error > _error_max)) {
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_error = _error_max;
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target = measurement + _error;
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limit_max = true;
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}
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// MIN(_Dxy_max, _D2xy_max / _kxy_P) limits the max accel to the point where max jerk is exceeded
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return sqrt_controller(_error, _kp, _D1_max, _dt);
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}
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// set_limits - sets the maximum error to limit output and first and second derivative of output
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// when using for a position controller, lim_err will be position error, lim_out will be correction velocity, lim_D will be acceleration, lim_D2 will be jerk
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void AC_P_1D::set_limits(float output_min, float output_max, float D_Out_max, float D2_Out_max)
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{
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_D1_max = 0.0f;
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_error_min = 0.0f;
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_error_max = 0.0f;
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if (is_positive(D_Out_max)) {
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_D1_max = D_Out_max;
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}
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if (is_positive(D2_Out_max) && is_positive(_kp)) {
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// limit the first derivative so as not to exceed the second derivative
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_D1_max = MIN(_D1_max, D2_Out_max / _kp);
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}
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if (is_negative(output_min) && is_positive(_kp)) {
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_error_min = inv_sqrt_controller(output_min, _kp, _D1_max);
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}
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if (is_positive(output_max) && is_positive(_kp)) {
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_error_max = inv_sqrt_controller(output_max, _kp, _D1_max);
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}
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}
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// set_error_limits - reduce maximum error to error_max
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// to be called after setting limits
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void AC_P_1D::set_error_limits(float error_min, float error_max)
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{
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if (is_negative(error_min)) {
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if (!is_zero(_error_min)) {
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_error_min = MAX(_error_min, error_min);
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} else {
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_error_min = error_min;
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}
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}
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if (is_positive(error_max)) {
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if (!is_zero(_error_max)) {
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_error_max = MIN(_error_max, error_max);
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} else {
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_error_max = error_max;
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}
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}
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}
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