HeadingSmoothing: fix angle wrapping and add unit tests

Co-authored-by: Matthias Grob <[email protected]>

src/lib/motion_planning/CMakeLists.txt

@@ -43,3 +43,4 @@ target_include_directories(motion_planning PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
 
 px4_add_unit_gtest(SRC VelocitySmoothingTest.cpp LINKLIBS motion_planning)
 px4_add_unit_gtest(SRC PositionSmoothingTest.cpp LINKLIBS motion_planning)
+px4_add_unit_gtest(SRC HeadingSmoothingTest.cpp LINKLIBS motion_planning)

src/lib/motion_planning/HeadingSmoothing.cpp

@@ -35,7 +35,7 @@
 
 HeadingSmoothing::HeadingSmoothing()
 {
-	_velocity_smoothing.setMaxVel(M_PI_F); // smoothed "velocity" is heading [-pi, pi]
+	_velocity_smoothing.setMaxVel(M_TWOPI_F); // "velocity" is heading. 2Pi limit is needed for correct angle wrapping
 }
 
 void HeadingSmoothing::reset(const float heading, const float heading_rate)

src/lib/motion_planning/HeadingSmoothingTest.cpp

@@ -0,0 +1,147 @@
+/****************************************************************************
+ *
+ *   Copyright (C) 2024 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.
+ *
+ ****************************************************************************/
+
+/**
+ * Test code for the Heading Smoothing library
+ * Run exclusively this test with the command "make tests TESTFILTER=HeadingSmoothing"
+ */
+
+#include "mathlib/math/Limits.hpp"
+#include <gtest/gtest.h>
+
+#include <motion_planning/HeadingSmoothing.hpp>
+
+using namespace matrix;
+
+class HeadingSmoothingTest : public ::testing::Test
+{
+public:
+	HeadingSmoothingTest()
+	{
+		_smoothing.setMaxHeadingRate(15.f);
+		_smoothing.setMaxHeadingAccel(1.f);
+	}
+
+	HeadingSmoothing _smoothing;
+	float _dt{.1f};
+};
+
+TEST_F(HeadingSmoothingTest, convergence)
+{
+	const float heading_current = math::radians(0.f);
+	const float heading_target = math::radians(5.f);
+	_smoothing.reset(heading_current, 0.f);
+
+	const int nb_steps = ceilf(1.f / _dt);
+
+	for (int i = 0; i < nb_steps; i++) {
+		_smoothing.update(heading_target, _dt);
+	}
+
+	const float heading = _smoothing.getSmoothedHeading();
+	const float heading_rate = _smoothing.getSmoothedHeadingRate();
+	EXPECT_EQ(heading, heading_target) << "heading (deg): " << math::degrees(heading);
+	EXPECT_EQ(heading_rate, 0.f);
+}
+
+TEST_F(HeadingSmoothingTest, zero_crossing)
+{
+	const float heading_current = math::radians(-95.f);
+	const float heading_target = math::radians(5.f);
+	_smoothing.reset(heading_current, 0.f);
+
+	const int nb_steps = ceilf(4.f / _dt);
+
+	for (int i = 0; i < nb_steps; i++) {
+		_smoothing.update(heading_target, _dt);
+	}
+
+	const float heading = _smoothing.getSmoothedHeading();
+	const float heading_rate = _smoothing.getSmoothedHeadingRate();
+	EXPECT_EQ(heading, heading_target) << "heading (deg): " << math::degrees(heading);
+	EXPECT_EQ(heading_rate, 0.f);
+}
+
+TEST_F(HeadingSmoothingTest, wrap_pi)
+{
+	const float heading_current = math::radians(-170.f);
+	const float heading_target = math::radians(170.f);
+	_smoothing.reset(heading_current, 0.f);
+
+	const int nb_steps = ceilf(2.f / _dt);
+
+	for (int i = 0; i < nb_steps; i++) {
+		_smoothing.update(heading_target, _dt);
+	}
+
+	const float heading = _smoothing.getSmoothedHeading();
+	const float heading_rate = _smoothing.getSmoothedHeadingRate();
+	EXPECT_EQ(heading, heading_target) << "heading (deg): " << math::degrees(heading);
+	EXPECT_EQ(heading_rate, 0.f);
+}
+
+TEST_F(HeadingSmoothingTest, positive_rate)
+{
+	const float max_heading_rate = .15f;
+	_smoothing.setMaxHeadingRate(max_heading_rate);
+	const float heading_current = math::radians(-170.f);
+	const float heading_target = math::radians(-20.f);
+	_smoothing.reset(heading_current, 0.f);
+
+	const int nb_steps = ceilf(2.f / _dt);
+
+	for (int i = 0; i < nb_steps; i++) {
+		_smoothing.update(heading_target, _dt);
+	}
+
+	const float heading_rate = _smoothing.getSmoothedHeadingRate();
+	EXPECT_EQ(heading_rate, max_heading_rate);
+}
+
+TEST_F(HeadingSmoothingTest, negative_rate)
+{
+	const float max_heading_rate = 0.15;
+	_smoothing.setMaxHeadingRate(max_heading_rate);
+	const float heading_current = math::radians(-20.f);
+	const float heading_target = math::radians(-140.f);
+	_smoothing.reset(heading_current, 0.f);
+
+	const int nb_steps = ceilf(2.f / _dt);
+
+	for (int i = 0; i < nb_steps; i++) {
+		_smoothing.update(heading_target, _dt);
+	}
+
+	const float heading_rate = _smoothing.getSmoothedHeadingRate();
+	EXPECT_EQ(heading_rate, -max_heading_rate);
+}