motion_planning: add heading smoother lib

wraps the velocity smoother, but is intended for generating smooth heading trajectories
handles angle wrap

src/lib/motion_planning/HeadingSmoother.hpp

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+/****************************************************************************
+ *
+ *   Copyright (c) 2023 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 HeadingSmoother.hpp
+ *
+ */
+
+#pragma once
+
+#include <motion_planning/VelocitySmoothing.hpp>
+#include <matrix/matrix/helper_functions.hpp>
+#include <float.h>
+
+/**
+ * @brief Wrapper class for smoothing heading via maximum angular acceleration limited trajectories.
+ *
+ * If instantiating the class before smoothing limits and initial states are known, make sure to properly initialize the
+ * smoother on the first pass with all of the following, default values cause very slow smoothing:
+ *
+ * reset(initial heading, initial heading rate);
+ * setMaxHeadingRate(max heading rate);
+ * setMaxHeadingAccel(max heading accel);
+ *
+ * At the desired time interval, call the update method to update the smoother:
+ *
+ * update(heading setpoint, time elapsed)
+ *
+ * Use the getters to retrieve the current smoothed states.
+ */
+class HeadingSmoother
+{
+public:
+	/**
+	 * @brief Construct with default smoothing initializations
+	 *
+	 */
+	HeadingSmoother()
+	{
+		reset(0.f, 0.f);
+		setMaxHeadingRate(VelocitySmoothing::kMinAccel);
+		setMaxHeadingAccel(VelocitySmoothing::kMinJerk);
+		_heading_smoother.setMaxVel(6.f * M_PI_F); // arbitrary large angle the wrapped value should never reach
+	}
+
+	/**
+	 * @brief construct with explicit smoothing initializations
+	 *
+	 * @param initial_heading [rad] [-pi, pi]
+	 * @param initial_heading_rate [rad/s]
+	 * @param max_heading_rate [rad/s]
+	 * @param max_heading_accel [rad/s^2]
+	 */
+	HeadingSmoother(const float initial_heading, const float initial_heading_rate, const float max_heading_rate,
+			const float max_heading_accel)
+	{
+		reset(initial_heading, initial_heading_rate);
+		setMaxHeadingRate(max_heading_rate); // is sanitized to lowest value in velocity smoothing setter
+		setMaxHeadingAccel(max_heading_accel); // is sanitized to lowest value in velocity smoothing setter
+		_heading_smoother.setMaxVel(6.f * M_PI_F); // arbitrary large angle the wrapped value should never reach
+	}
+
+	~HeadingSmoother() = default;
+
+	/**
+	 * @return [rad] [-pi,pi] smoothed heading
+	 */
+	float getSmoothedHeading() const { return _heading_smoother.getCurrentVelocity(); }
+
+	/**
+	 * @return [rad/s] smoothed heading rate
+	 */
+	float getSmoothedHeadingRate() const { return _heading_smoother.getCurrentAcceleration(); }
+
+	/**
+	 * @param max_heading_rate [rad/s]
+	 */
+	void setMaxHeadingRate(const float max_heading_rate) { _heading_smoother.setMaxAccel(max_heading_rate); }
+
+	/**
+	 * @param max_heading_accel [rad/s^2]
+	 */
+	void setMaxHeadingAccel(const float max_heading_accel) { _heading_smoother.setMaxJerk(max_heading_accel); }
+
+	/**
+	 * @brief updates the heading setpoint, re-calculates trajectory, and takes an integration step
+	 *
+	 * @param heading_setpoint [rad]
+	 * @param time_elapsed [s]
+	 */
+	void update(const float heading_setpoint, const float time_elapsed)
+	{
+		const float delta_heading_wrapped = matrix::wrap_pi(heading_setpoint - getSmoothedHeading());
+		const float unwrapped_heading_setpoint = delta_heading_wrapped + getSmoothedHeading();
+
+		_heading_smoother.updateDurations(unwrapped_heading_setpoint);
+		_heading_smoother.updateTraj(time_elapsed);
+
+		const float wrapped_current_heading = matrix::wrap_pi(getSmoothedHeading());
+		_heading_smoother.setCurrentVelocity(wrapped_current_heading);
+	}
+
+	/**
+	 * @brief resets internal trajectory states, handles heading wrap
+	 *
+	 * @param heading [rad] [-pi,pi]
+	 * @param heading_rate [rad/s]
+	 */
+	void reset(const float heading, const float heading_rate)
+	{
+		const float wrapped_heading = matrix::wrap_pi(heading);
+		_heading_smoother.setCurrentVelocity(wrapped_heading);
+		_heading_smoother.setCurrentAcceleration(heading_rate);
+	}
+
+	// [rad/s] minimum value of the smoother's maximum heading rate
+	static constexpr float kMinHeadingRate = VelocitySmoothing::kMinAccel;
+
+	// [rad/s^2] minimum value of the smoother's maximum heading acceleration
+	static constexpr float kMinHeadingAccel = VelocitySmoothing::kMinJerk;
+
+private:
+
+	VelocitySmoothing _heading_smoother;
+};