SlewRate: Add SlewRateYaw handling [-pi,pi] wraps

src/lib/slew_rate/CMakeLists.txt

@@ -42,3 +42,4 @@ target_include_directories(SlewRate
 target_link_libraries(SlewRate PUBLIC mathlib)
 
 px4_add_unit_gtest(SRC SlewRateTest.cpp LINKLIBS SlewRate)
+px4_add_unit_gtest(SRC SlewRateYawTest.cpp LINKLIBS SlewRate)

src/lib/slew_rate/SlewRate.hpp

@@ -79,7 +79,7 @@ public:
 		return _value;
 	}
 
-private:
+protected:
 	Type _slew_rate{}; ///< maximum rate of change for the value
 	Type _value{}; ///< state to keep last value of the slew rate
 };

src/lib/slew_rate/SlewRateYaw.hpp

@@ -0,0 +1,64 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2020 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 SlewRateYaw.hpp
+ *
+ * Library limit the rate of change of a [-pi,pi] range yaw value with a maximum slew rate.
+ *
+ * @author Matthias Grob <maetugr@gmail.com>
+ */
+
+#pragma once
+
+#include "SlewRate.hpp"
+
+template<typename Type>
+class SlewRateYaw : public SlewRate<Type>
+{
+public:
+	SlewRateYaw() = default;
+	~SlewRateYaw() = default;
+
+	/**
+	 * Update slewrate with yaw wrapping [-pi,pi]
+	 * @param new_value desired new value
+	 * @param deltatime time in seconds since last update
+	 * @return actual value that complies with the slew rate
+	 */
+	Type update(const Type new_value, const float deltatime)
+	{
+		const Type d_wrapped = matrix::wrap_pi(new_value - this->_value);
+		return matrix::wrap_pi(SlewRate<Type>::update(this->_value + d_wrapped, deltatime));
+	}
+};

src/lib/slew_rate/SlewRateYawTest.cpp

@@ -0,0 +1,122 @@
+/****************************************************************************
+ *
+ *   Copyright (C) 2020 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.
+ *
+ ****************************************************************************/
+
+#include <gtest/gtest.h>
+#include <SlewRateYaw.hpp>
+
+TEST(SlewRateYawTest, SlewUpLimited)
+{
+	SlewRateYaw<float> _slew_rate_yaw;
+	_slew_rate_yaw.setSlewRate(.15f);
+	_slew_rate_yaw.setForcedValue(1.1f);
+
+	for (int i = 1; i <= 10; i++) {
+		EXPECT_FLOAT_EQ(_slew_rate_yaw.update(3.f, 1.f), 1.1f + i * .15f);
+	}
+}
+
+TEST(SlewRateYawTest, SlewDownLimited)
+{
+	SlewRateYaw<float> _slew_rate_yaw;
+	_slew_rate_yaw.setSlewRate(.1f);
+	_slew_rate_yaw.setForcedValue(.5f);
+
+	for (int i = 1; i <= 10; i++) {
+		EXPECT_NEAR(_slew_rate_yaw.update(-2.f, 1.f), .5f - i * .1f, 1e-7f);
+	}
+}
+
+TEST(SlewRateYawTest, ReachValueSlewed)
+{
+	SlewRateYaw<float> _slew_rate_yaw;
+	_slew_rate_yaw.setSlewRate(.2f);
+	_slew_rate_yaw.setForcedValue(1.f);
+
+	for (int i = 1; i <= 10; i++) {
+		EXPECT_FLOAT_EQ(_slew_rate_yaw.update(3.f, 1.f), 1.f + i * .2f);
+	}
+
+	for (int i = 1; i <= 10; i++) {
+		EXPECT_FLOAT_EQ(_slew_rate_yaw.update(3.f, 1.f), 3.f);
+	}
+}
+
+TEST(SlewRateYawTest, SlewUpWrappedOutput)
+{
+	// put the goal value always a bit further away such that at some point the output has to wrap
+	SlewRateYaw<float> _slew_rate_yaw;
+	_slew_rate_yaw.setSlewRate(.2f);
+	_slew_rate_yaw.setForcedValue(0.f);
+
+	for (int i = 1; i <= 30; i++) {
+		EXPECT_NEAR(_slew_rate_yaw.update(i * .25f, 1.f), matrix::wrap_pi(i * .2f), 1e-5f);
+	}
+}
+
+TEST(SlewRateYawTest, SlewDownWrappedOutput)
+{
+	// put the goal value always a bit further away such that at some point the output has to wrap
+	SlewRateYaw<float> _slew_rate_yaw;
+	_slew_rate_yaw.setSlewRate(.2f);
+	_slew_rate_yaw.setForcedValue(0.f);
+
+	for (int i = 1; i <= 50; i++) {
+		EXPECT_NEAR(_slew_rate_yaw.update(i * -.25f, 1.f), matrix::wrap_pi(i * -.2f), 1e-5f);
+	}
+}
+
+TEST(SlewRateYawTest, SlewUpWrappedInput)
+{
+	// put the goal value always a bit further away such that at some point the output has to wrap
+	SlewRateYaw<float> _slew_rate_yaw;
+	_slew_rate_yaw.setSlewRate(.2f);
+	_slew_rate_yaw.setForcedValue(0.f);
+
+	for (int i = 1; i <= 50; i++) {
+		EXPECT_NEAR(_slew_rate_yaw.update(matrix::wrap_pi(i * .25f), 1.f), matrix::wrap_pi(i * .2f), 1e-5f);
+	}
+}
+
+TEST(SlewRateYawTest, SlewShortWayInput)
+{
+	SlewRateYaw<float> _slew_rate_yaw;
+	_slew_rate_yaw.setSlewRate(1.f);
+	_slew_rate_yaw.setForcedValue(0.f);
+
+	EXPECT_FLOAT_EQ(_slew_rate_yaw.update(3.f, 1.f), 1.f);
+	EXPECT_FLOAT_EQ(_slew_rate_yaw.update(5.f, 1.f), 0.f);
+	EXPECT_FLOAT_EQ(_slew_rate_yaw.update(5.f, 1.f), -1.f);
+	EXPECT_FLOAT_EQ(_slew_rate_yaw.update(4.f, 1.f), -2.f);
+	EXPECT_FLOAT_EQ(_slew_rate_yaw.update(3.f, 1.f), -3.f);
+	EXPECT_FLOAT_EQ(_slew_rate_yaw.update(5.f, 1.f), -2.f);
+}