forked from Archive/PX4-Autopilot
140 lines
4.7 KiB
C++
140 lines
4.7 KiB
C++
/****************************************************************************
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*
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* Copyright (c) 2013-2016 Estimation and Control Library (ECL). All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name ECL nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/**
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* @file ecl_wheel_controller.cpp
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* Implementation of a simple PID wheel controller for heading tracking.
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*
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* Authors and acknowledgements in header.
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*/
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#include "ecl_wheel_controller.h"
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#include <stdint.h>
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#include <float.h>
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#include <geo/geo.h>
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#include <ecl/ecl.h>
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#include <mathlib/mathlib.h>
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#include <systemlib/err.h>
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#include <ecl/ecl.h>
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ECL_WheelController::ECL_WheelController() :
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ECL_Controller("wheel")
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{
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}
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float ECL_WheelController::control_bodyrate(const struct ECL_ControlData &ctl_data)
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{
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/* Do not calculate control signal with bad inputs */
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if (!(PX4_ISFINITE(ctl_data.body_z_rate) &&
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PX4_ISFINITE(ctl_data.groundspeed) &&
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PX4_ISFINITE(ctl_data.groundspeed_scaler))) {
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return math::constrain(_last_output, -1.0f, 1.0f);
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}
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/* get the usual dt estimate */
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uint64_t dt_micros = ecl_elapsed_time(&_last_run);
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_last_run = ecl_absolute_time();
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float dt = (float)dt_micros * 1e-6f;
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/* lock integral for long intervals */
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bool lock_integrator = ctl_data.lock_integrator;
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if (dt_micros > 500000) {
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lock_integrator = true;
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}
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/* input conditioning */
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float min_speed = 1.0f;
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/* Calculate body angular rate error */
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_rate_error = _rate_setpoint - ctl_data.body_z_rate; //body angular rate error
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if (!lock_integrator && _k_i > 0.0f && ctl_data.groundspeed > min_speed) {
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float id = _rate_error * dt * ctl_data.groundspeed_scaler;
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/*
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* anti-windup: do not allow integrator to increase if actuator is at limit
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*/
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if (_last_output < -1.0f) {
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/* only allow motion to center: increase value */
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id = math::max(id, 0.0f);
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} else if (_last_output > 1.0f) {
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/* only allow motion to center: decrease value */
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id = math::min(id, 0.0f);
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}
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_integrator += id * _k_i;
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}
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/* integrator limit */
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//xxx: until start detection is available: integral part in control signal is limited here
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float integrator_constrained = math::constrain(_integrator, -_integrator_max, _integrator_max);
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/* Apply PI rate controller and store non-limited output */
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_last_output = _rate_setpoint * _k_ff * ctl_data.groundspeed_scaler +
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ctl_data.groundspeed_scaler * ctl_data.groundspeed_scaler * (_rate_error * _k_p + integrator_constrained);
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return math::constrain(_last_output, -1.0f, 1.0f);
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}
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float ECL_WheelController::control_attitude(const struct ECL_ControlData &ctl_data)
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{
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/* Do not calculate control signal with bad inputs */
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if (!(PX4_ISFINITE(ctl_data.yaw_setpoint) &&
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PX4_ISFINITE(ctl_data.yaw))) {
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return _rate_setpoint;
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}
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/* Calculate the error */
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float yaw_error = _wrap_pi(ctl_data.yaw_setpoint - ctl_data.yaw);
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/* Apply P controller: rate setpoint from current error and time constant */
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_rate_setpoint = yaw_error / _tc;
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/* limit the rate */
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if (_max_rate > 0.01f) {
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if (_rate_setpoint > 0.0f) {
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_rate_setpoint = (_rate_setpoint > _max_rate) ? _max_rate : _rate_setpoint;
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} else {
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_rate_setpoint = (_rate_setpoint < -_max_rate) ? -_max_rate : _rate_setpoint;
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}
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}
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return _rate_setpoint;
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}
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