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PX4-Autopilot/src/lib/system_identification/system_identification.hpp
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2021-10-02 18:12:05 -04:00

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*
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/**
* @file system_identification.hpp
*
* @author Mathieu Bresciani <mathieu@auterion.com>
*/
#pragma once
#include <lib/mathlib/math/filter/AlphaFilter.hpp>
#include <matrix/matrix/math.hpp>
#include <mathlib/mathlib.h>
#include <mathlib/math/filter/LowPassFilter2p.hpp>
#include <px4_platform_common/defines.h>
#include "arx_rls.hpp"
class SystemIdentification final
{
public:
SystemIdentification() = default;
~SystemIdentification() = default;
void reset(const matrix::Vector<float, 5> &id_state_init = {});
void update(float u, float y); // update filters and model
void update(); // update model only (to be called after updateFilters)
void updateFilters(float u, float y);
bool areFiltersInitialized() const { return _are_filters_initialized; }
void updateFitness();
const matrix::Vector<float, 5> &getCoefficients() const { return _rls.getCoefficients(); }
const matrix::Vector<float, 5> getVariances() const { return _rls.getVariances(); }
const matrix::Vector<float, 5> &getDiffEstimate() const { return _rls.getDiffEstimate(); }
float getFitness() const { return _fitness_lpf.getState(); }
float getInnovation() const { return _rls.getInnovation(); }
void setLpfCutoffFrequency(float sample_freq, float cutoff)
{
_u_lpf.set_cutoff_frequency(sample_freq, cutoff);
_y_lpf.set_cutoff_frequency(sample_freq, cutoff);
}
void setHpfCutoffFrequency(float sample_freq, float cutoff) { _alpha_hpf = sample_freq / (sample_freq + 2.f * M_PI_F * cutoff); }
void setForgettingFactor(float time_constant, float dt) { _rls.setForgettingFactor(time_constant, dt); }
void setFitnessLpfTimeConstant(float time_constant, float dt)
{
_fitness_lpf.setParameters(dt, time_constant);
_dt = dt;
}
float getFilteredInputData() const { return _u_hpf; }
float getFilteredOutputData() const { return _y_hpf; }
private:
ArxRls<2, 2, 1> _rls;
math::LowPassFilter2p<float> _u_lpf{400.f, 30.f};
math::LowPassFilter2p<float> _y_lpf{400.f, 30.f};
//TODO: replace by HighPassFilter class
float _alpha_hpf{0.f};
float _u_hpf{0.f};
float _y_hpf{0.f};
float _u_prev{0.f};
float _y_prev{0.f};
bool _are_filters_initialized{false};
AlphaFilter<float> _fitness_lpf;
float _dt{0.1f};
};