forked from Archive/PX4-Autopilot
206 lines
7.0 KiB
C++
206 lines
7.0 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_yaw_controller.cpp
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* Implementation of a simple orthogonal coordinated turn yaw PID controller.
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*
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* Authors and acknowledgements in header.
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*/
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#include "ecl_yaw_controller.h"
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#include <float.h>
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#include <geo/geo.h>
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#include <mathlib/mathlib.h>
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float ECL_YawController::control_attitude(const struct ECL_ControlData &ctl_data)
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{
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switch (_coordinated_method) {
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case COORD_METHOD_OPEN:
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return control_attitude_impl_openloop(ctl_data);
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case COORD_METHOD_CLOSEACC:
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return control_attitude_impl_accclosedloop(ctl_data);
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default:
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static ecl_abstime last_print = 0;
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if (ecl_elapsed_time(&last_print) > 5e6) {
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ECL_WARN("invalid param setting FW_YCO_METHOD");
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last_print = ecl_absolute_time();
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}
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}
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return _rate_setpoint;
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}
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float ECL_YawController::control_attitude_impl_openloop(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 (!(ISFINITE(ctl_data.roll) &&
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ISFINITE(ctl_data.pitch) &&
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ISFINITE(ctl_data.roll_rate_setpoint) &&
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ISFINITE(ctl_data.pitch_rate_setpoint))) {
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return _rate_setpoint;
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}
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float constrained_roll;
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bool inverted = false;
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/* roll is used as feedforward term and inverted flight needs to be considered */
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if (fabsf(ctl_data.roll) < math::radians(90.0f)) {
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/* not inverted, but numerically still potentially close to infinity */
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constrained_roll = math::constrain(ctl_data.roll, math::radians(-80.0f), math::radians(80.0f));
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} else {
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inverted = true;
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// inverted flight, constrain on the two extremes of -pi..+pi to avoid infinity
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//note: the ranges are extended by 10 deg here to avoid numeric resolution effects
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if (ctl_data.roll > 0.0f) {
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/* right hemisphere */
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constrained_roll = math::constrain(ctl_data.roll, math::radians(100.0f), math::radians(180.0f));
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} else {
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/* left hemisphere */
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constrained_roll = math::constrain(ctl_data.roll, math::radians(-180.0f), math::radians(-100.0f));
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}
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}
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constrained_roll = math::constrain(constrained_roll, -fabsf(ctl_data.roll_setpoint), fabsf(ctl_data.roll_setpoint));
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if (!inverted) {
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/* Calculate desired yaw rate from coordinated turn constraint / (no side forces) */
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_rate_setpoint = tanf(constrained_roll) * cosf(ctl_data.pitch) * CONSTANTS_ONE_G / (ctl_data.airspeed <
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ctl_data.airspeed_min ? ctl_data.airspeed_min : ctl_data.airspeed);
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}
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if (!ISFINITE(_rate_setpoint)) {
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ECL_WARN("yaw rate sepoint not finite");
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_rate_setpoint = 0.0f;
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}
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return _rate_setpoint;
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}
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float ECL_YawController::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 (!(ISFINITE(ctl_data.roll) && ISFINITE(ctl_data.pitch) && ISFINITE(ctl_data.body_y_rate) &&
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ISFINITE(ctl_data.body_z_rate) && ISFINITE(ctl_data.pitch_rate_setpoint) &&
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ISFINITE(ctl_data.airspeed_min) && ISFINITE(ctl_data.airspeed_max) &&
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ISFINITE(ctl_data.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 airspeed = ctl_data.airspeed;
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if (!ISFINITE(airspeed)) {
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/* airspeed is NaN, +- INF or not available, pick center of band */
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airspeed = 0.5f * (ctl_data.airspeed_min + ctl_data.airspeed_max);
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} else if (airspeed < ctl_data.airspeed_min) {
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airspeed = ctl_data.airspeed_min;
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}
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/* Close the acceleration loop if _coordinated_method wants this: change body_rate setpoint */
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if (_coordinated_method == COORD_METHOD_CLOSEACC) {
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// XXX lateral acceleration needs to go into integrator with a gain
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//_bodyrate_setpoint -= (ctl_data.acc_body_y / (airspeed * cosf(ctl_data.pitch)));
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}
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/* Calculate body angular rate error */
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_rate_error = _bodyrate_setpoint - ctl_data.body_z_rate; // body angular rate error
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if (!lock_integrator && _k_i > 0.0f && airspeed > 0.5f * ctl_data.airspeed_min) {
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float id = _rate_error * dt;
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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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/* add and constrain */
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_integrator = math::constrain(_integrator + id * _k_i, -_integrator_max, _integrator_max);
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}
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/* Apply PI rate controller and store non-limited output */
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_last_output = (_bodyrate_setpoint * _k_ff + _rate_error * _k_p + _integrator) * ctl_data.scaler *
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ctl_data.scaler; //scaler is proportional to 1/airspeed
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return math::constrain(_last_output, -1.0f, 1.0f);
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}
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float ECL_YawController::control_attitude_impl_accclosedloop(const struct ECL_ControlData &ctl_data)
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{
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(void)ctl_data; // unused
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/* dont set a rate setpoint */
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return 0.0f;
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}
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float ECL_YawController::control_euler_rate(const struct ECL_ControlData &ctl_data)
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{
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/* Transform setpoint to body angular rates (jacobian) */
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_bodyrate_setpoint = -sinf(ctl_data.roll) * ctl_data.pitch_rate_setpoint +
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cosf(ctl_data.roll) * cosf(ctl_data.pitch) * _rate_setpoint;
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set_bodyrate_setpoint(_bodyrate_setpoint);
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return control_bodyrate(ctl_data);
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}
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