ManualSmoothing: new class for smoothing setpoints generated from sticks

src/lib/FlightTasks/tasks/Utility/ManualSmoothingZ.cpp

@@ -0,0 +1,167 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2017 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 ManualSmoothingZ.hpp
+ *
+ * This Class is used for smoothing the velocity setpoints in Z-direction.
+ */
+
+
+#include "ManualSmoothingZ.hpp"
+#include "uORB/topics/parameter_update.h"
+#include <mathlib/mathlib.h>
+#include <float.h>
+
+ManualSmoothingZ::ManualSmoothingZ(const float &vel, const float &stick) :
+	_vel(vel), _stick(stick)
+{
+	_acc_max_up_h = param_find("MPC_ACC_UP_MAX");
+	_acc_max_down_h = param_find("MPC_ACC_DOWN_MAX");
+	_jerk_max = param_find("MPC_JERK_MAX");
+
+	/* Load the params the very first time */
+	setParams();
+}
+
+/* in manual altitude control apply acceleration limit based on stick input
+ * we consider two states
+ * 1.) brake
+ * 2.) accelerate */
+
+void
+ManualSmoothingZ::smoothVelFromSticks(float vel_sp[2], const float dt)
+{
+	updateParams();
+
+	updateAcceleration(vel_sp[1], dt);
+
+	velocitySlewRate(vel_sp, dt);
+
+}
+
+void
+ManualSmoothingZ::updateParams()
+{
+	bool updated;
+	parameter_update_s param_update;
+	orb_check(_parameter_sub, &updated);
+
+	if (updated) {
+		orb_copy(ORB_ID(parameter_update), _parameter_sub, &param_update);
+		setParams();
+	}
+}
+
+void
+ManualSmoothingZ::updateAcceleration(float &vel_sp_prev, const float dt)
+{
+	/* check if zero input stick */
+	const bool is_current_zero = (fabsf(_stick) <= FLT_EPSILON);
+
+	/* default is acceleration */
+	Intention intention = Intention::acceleration;
+
+	/* check zero input stick */
+	if (is_current_zero) {
+		intention = Intention::brake;
+	}
+
+	/*
+	 * update intention
+	 */
+	if ((_intention != Intention::brake) && (intention == Intention::brake)) {
+
+		/* we start with lowest acceleration */
+		_acc_state_dependent = _acc_max_down;
+
+		/* reset slewrate: this ensures that there
+		 * is no delay present because of the slewrate
+		 */
+		vel_sp_prev = _vel;
+
+	}
+
+	switch (intention) {
+	case Intention::brake: {
+
+			/* limit jerk when braking to zero */
+			float jerk = (_acc_max_up - _acc_state_dependent) / dt;
+
+			if (jerk > _jerk_max) {
+				_acc_state_dependent = _jerk_max * dt + _acc_state_dependent;
+
+			} else {
+				_acc_state_dependent = _acc_max_up;
+			}
+
+			break;
+		}
+
+	case Intention::acceleration: {
+
+			_acc_state_dependent = (getMaxAcceleration() - _acc_max_down)
+					       * fabsf(_stick) + _acc_max_down;
+			break;
+		}
+	}
+
+	_intention = intention;
+}
+
+void
+ManualSmoothingZ::setParams()
+{
+	param_get(_acc_max_up_h, &_acc_max_up);
+	param_get(_acc_max_down_h, &_acc_max_down);
+	param_get(_jerk_max_h, &_jerk_max);
+
+}
+
+float
+ManualSmoothingZ::getMaxAcceleration()
+{
+	return (_stick <= 0.0f) ? _acc_max_up : _acc_max_down;
+}
+
+void
+ManualSmoothingZ::velocitySlewRate(float vel_sp[2], const float dt)
+{
+	/* limit vertical acceleration */
+	float acc = (vel_sp[0] - vel_sp[1]) / dt;
+	float max_acc = (acc < 0.0f) ? -_acc_state_dependent : _acc_state_dependent;
+
+	if (fabsf(acc) > fabsf(max_acc)) {
+		vel_sp[0] = max_acc * dt + vel_sp[1];
+	}
+}

src/lib/FlightTasks/tasks/Utility/ManualSmoothingZ.hpp

@@ -0,0 +1,82 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2017 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 SmoothingZ.hpp
+ *
+ * This Class is used for smoothing the velocity setpoints in Z-direction.
+ */
+
+#pragma once
+
+#include <systemlib/param/param.h>
+
+
+class ManualSmoothingZ
+{
+public:
+	ManualSmoothingZ(const float &vel, const float &stick);
+	~ManualSmoothingZ();
+
+	void smoothVelFromSticks(float vel_sp[2], const float dt);
+
+
+
+
+private:
+
+	enum class Intention {
+		brake,
+		acceleration,
+	};
+	Intention _intention{Intention::brake};
+
+	const float &_vel;
+	const float &_stick;
+
+	param_t _acc_max_up_h{PARAM_INVALID};
+	param_t _acc_max_down_h{PARAM_INVALID};
+	param_t _jerk_max_h{PARAM_INVALID};
+	float _acc_max_up{0.0f};
+	float _acc_max_down{0.0f};
+	float _jerk_max{10000.0f};
+	float _acc_state_dependent{0.0f};
+	int _parameter_sub{-1};
+
+
+	void velocitySlewRate(float vel_sp[2], const float dt);
+	void updateParams();
+	void updateAcceleration(float &vel_sp_prev, const float dt);
+	void setParams();
+	float getMaxAcceleration();
+};