sysID: add system identification library

2026-11-09 06:31:35 +08:00 · 2021-10-02 18:12:05 -04:00
parent d504b49695
commit 404145c655
8 changed files with 869 additions and 0 deletions
@@ -0,0 +1,101 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2020-2021 PX4 Development Team. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/**
+ * @file system_identification.cpp
+ *
+ * @author Mathieu Bresciani <mathieu@auterion.com>
+ */
+
+#include "system_identification.hpp"
+
+void SystemIdentification::reset(const matrix::Vector<float, 5> &id_state_init)
+{
+	_rls.reset(id_state_init);
+	_u_lpf.reset(0.f);
+	_u_lpf.reset(0.f);
+	_u_hpf = 0.f;
+	_y_hpf = 0.f;
+	_u_prev = 0.f;
+	_y_prev = 0.f;
+	_fitness_lpf.reset(10.f);
+	_are_filters_initialized = false;
+}
+
+void SystemIdentification::update(float u, float y)
+{
+	updateFilters(u, y);
+	update();
+}
+
+void SystemIdentification::update()
+{
+	_rls.update(_u_hpf, _y_hpf);
+	updateFitness();
+}
+
+void SystemIdentification::updateFilters(float u, float y)
+{
+	if (!_are_filters_initialized) {
+		_u_lpf.reset(u);
+		_y_lpf.reset(y);
+		_u_hpf = 0.f;
+		_y_hpf = 0.f;
+		_u_prev = u;
+		_y_prev = y;
+		_are_filters_initialized = true;
+		return;
+	}
+
+	const float u_lpf = _u_lpf.apply(u);
+	const float y_lpf = _y_lpf.apply(y);
+	_u_hpf = _alpha_hpf * _u_hpf + _alpha_hpf * (u_lpf - _u_prev);
+	_y_hpf = _alpha_hpf * _y_hpf + _alpha_hpf * (y_lpf - _y_prev);
+
+	_u_prev = u_lpf;
+	_y_prev = y_lpf;
+}
+
+void SystemIdentification::updateFitness()
+{
+	const matrix::Vector<float, 5> &diff = _rls.getDiffEstimate();
+	float sum = 0.f;
+
+	for (size_t i = 0; i < 5; i++) {
+		sum += diff(i);
+	}
+
+	if (_dt > FLT_EPSILON) {
+		_fitness_lpf.update(sum / _dt);
+	}
+}