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211 lines
7.2 KiB
211 lines
7.2 KiB
/**************************************************************************** |
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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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ECL_YawController::ECL_YawController() : |
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ECL_Controller("yaw"), |
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_coordinated_min_speed(1.0f), |
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_max_rate(0.0f), /* disable by default */ |
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_coordinated_method(0) |
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{ |
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} |
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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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/* 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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