forked from Archive/PX4-Autopilot
Create total energy control system implementation
This is a new, clean and streamlined variant of the mathematical derivation I created a few years ago.
This commit is contained in:
Paul Riseborough
Lorenz Meier
parent
9eb860fabd
commit
79995b2c15
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@ -56,6 +56,7 @@ px4_add_module(
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EKF/vel_pos_fusion.cpp
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EKF/drag_fusion.cpp
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l1/ecl_l1_pos_controller.cpp
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tecs/tecs.cpp
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validation/data_validator.cpp
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validation/data_validator_group.cpp
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DEPENDS
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@ -485,6 +485,11 @@ void Ekf::calculateOutputStates()
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// corrrect for measured accceleration due to gravity
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delta_vel_NED(2) += _gravity_mss * imu_new.delta_vel_dt;
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// calculate the earth frame velocity derivatives
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if (imu_new.delta_vel_dt > 1e-4f) {
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_vel_deriv_ned = delta_vel_NED * (1.0f / imu_new.delta_vel_dt);
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}
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// save the previous velocity so we can use trapezidal integration
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Vector3f vel_last = _output_new.vel;
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@ -502,6 +507,8 @@ void Ekf::calculateOutputStates()
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// accumulate the time for each update
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_output_vert_new.dt += imu_new.delta_vel_dt;
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// correct velocity for IMU offset
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if (_imu_sample_new.delta_ang_dt > 1e-4f) {
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// calculate the average angular rate across the last IMU update
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Vector3f ang_rate = _imu_sample_new.delta_ang * (1.0f / _imu_sample_new.delta_ang_dt);
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@ -511,6 +518,8 @@ void Ekf::calculateOutputStates()
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// rotate the relative velocity into earth frame
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_vel_imu_rel_body_ned = _R_to_earth_now * vel_imu_rel_body;
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}
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// store the INS states in a ring buffer with the same length and time coordinates as the IMU data buffer
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if (_imu_updated) {
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_output_buffer.push(_output_new);
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@ -231,6 +231,14 @@ public:
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}
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}
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// get the NED velocity derivative in earth frame
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void get_vel_deriv_ned(float *vel_deriv)
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{
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for (unsigned i = 0; i < 3; i++) {
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vel_deriv[i] = _vel_deriv_ned(i);
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}
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}
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// get the derivative of the vertical position of the body frame origin in local NED earth frame
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void get_pos_d_deriv(float *pos_d_deriv)
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{
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@ -380,6 +388,7 @@ protected:
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imuSample _imu_sample_new{}; // imu sample capturing the newest imu data
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Matrix3f _R_to_earth_now; // rotation matrix from body to earth frame at current time
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Vector3f _vel_imu_rel_body_ned; // velocity of IMU relative to body origin in NED earth frame
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Vector3f _vel_deriv_ned; // velocity derivative at the IMU in NED earth frame (m/s/s)
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uint64_t _imu_ticks{0}; // counter for imu updates
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@ -0,0 +1,645 @@
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/****************************************************************************
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*
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* Copyright (c) 2017 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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#include "tecs.h"
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#include <ecl/ecl.h>
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#include <systemlib/err.h>
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#include <geo/geo.h>
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using math::constrain;
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using math::max;
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using math::min;
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/**
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* @file tecs.cpp
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*
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* @author Paul Riseborough
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*/
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/*
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* This function implements a complementary filter to estimate the climb rate when
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* inertial nav data is not available. It also calculates a true airpseed derivative
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* which is used by the airspeed complimentary filter.
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*/
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void TECS::update_vehicle_state_estimates(float airspeed, const math::Matrix<3, 3> &rotMat,
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const math::Vector<3> &accel_body, bool altitude_lock, bool in_air,
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float altitude, bool vz_valid, float vz, float az)
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{
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// calculate the time lapsed since the last update
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uint64_t now = ecl_absolute_time();
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float dt = max((now - _state_update_timestamp), static_cast<uint64_t>(0)) * 1.0e-6f;
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bool reset_altitude = false;
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if (_state_update_timestamp == 0 || dt > DT_MAX) {
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dt = DT_DEFAULT;
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reset_altitude = true;
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}
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if (!altitude_lock || !in_air) {
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reset_altitude = true;
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}
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if (reset_altitude) {
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_vert_pos_state = altitude;
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if (vz_valid) {
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_vert_vel_state = -vz;
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} else {
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_vert_vel_state = 0.0f;
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}
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_vert_accel_state = 0.0f;
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_states_initalized = false;
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}
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_state_update_timestamp = now;
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_EAS = airspeed;
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_in_air = in_air;
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// Genrate the height and climb rate state estimates
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if (vz_valid) {
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// Set the velocity and position state to the the INS data
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_vert_vel_state = -vz;
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_vert_pos_state = altitude;
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} else {
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// Get height acceleration
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float hgt_ddot_mea = -az;
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// If we have no vertical INS data, estimate the vertical velocity using a complementary filter
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// Perform filter calculation using backwards Euler integration
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// Coefficients selected to place all three filter poles at omega
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// Reference Paper: Optimising the Gains of the Baro-Inertial Vertical Channel
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// Widnall W.S, Sinha P.K, AIAA Journal of Guidance and Control, 78-1307R
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float omega2 = _hgt_estimate_freq * _hgt_estimate_freq;
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float hgt_err = altitude - _vert_pos_state;
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float vert_accel_input = hgt_err * omega2 * _hgt_estimate_freq;
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_vert_accel_state = _vert_accel_state + vert_accel_input * dt;
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float vert_vel_input = _vert_accel_state + hgt_ddot_mea + hgt_err * omega2 * 3.0f;
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_vert_vel_state = _vert_vel_state + vert_vel_input * dt;
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float vert_pos_input = _vert_vel_state + hgt_err * _hgt_estimate_freq * 3.0f;
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// If more than 1 second has elapsed since last update then reset the position state
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// to the measured height
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if (reset_altitude) {
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_vert_pos_state = altitude;
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} else {
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_vert_pos_state = _vert_pos_state + vert_pos_input * dt;
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}
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}
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// Update and average speed rate of change if airspeed is being measured
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if (PX4_ISFINITE(airspeed) && airspeed_sensor_enabled()) {
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// Assuming the vehicle is flying X axis forward, use the X axis measured acceleration
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// compensated for gravity to estimate the rate of change of speed
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float speed_deriv_raw = rotMat(2, 0) * CONSTANTS_ONE_G + accel_body(0);
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// Apply some noise filtering
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_speed_derivative = 0.95f * _speed_derivative + 0.05f * speed_deriv_raw;
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} else {
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_speed_derivative = 0.0f;
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}
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if (!_in_air) {
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_states_initalized = false;
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}
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}
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void TECS::_update_speed_states(float airspeed_setpoint, float indicated_airspeed, float EAS2TAS)
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{
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// Calculate the time in seconds since the last update and use the default time step value if out of bounds
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uint64_t now = ecl_absolute_time();
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float dt = max((now - _speed_update_timestamp), UINT64_C(0)) * 1.0e-6f;
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if (dt < DT_MIN || dt > DT_MAX) {
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dt = DT_DEFAULT;
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}
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// Convert equivalent airspeed quantities to true airspeed
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_EAS_setpoint = airspeed_setpoint;
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_TAS_setpoint = _EAS_setpoint * EAS2TAS;
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_TAS_max = _indicated_airspeed_max * EAS2TAS;
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_TAS_min = _indicated_airspeed_min * EAS2TAS;
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// If airspeed measurements are not being used, fix the airspeed estimate to halfway between
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// min and max limits
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if (!PX4_ISFINITE(indicated_airspeed) || !airspeed_sensor_enabled()) {
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_EAS = 0.5f * (_indicated_airspeed_min + _indicated_airspeed_max);
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} else {
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_EAS = indicated_airspeed;
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}
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// If first time through or not flying, reset airspeed states
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if (_speed_update_timestamp == 0 || !_in_air) {
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_tas_rate_state = 0.0f;
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_tas_state = (_EAS * EAS2TAS);
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}
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// Obtain a smoothed airspeed estimate using a second order complementary filter
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// Update TAS rate state
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float tas_error = (_EAS * EAS2TAS) - _tas_state;
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float tas_rate_state_input = tas_error * _tas_estimate_freq * _tas_estimate_freq;
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// limit integrator input to prevent windup
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if (_tas_state < 3.1f) {
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tas_rate_state_input = max(tas_rate_state_input, 0.0f);
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}
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// Update TAS state
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_tas_rate_state = _tas_rate_state + tas_rate_state_input * dt;
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float tas_state_input = _tas_rate_state + _speed_derivative + tas_error * _tas_estimate_freq * 1.4142f;
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_tas_state = _tas_state + tas_state_input * dt;
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// Limit the airspeed state to a minimum of 3 m/s
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_tas_state = max(_tas_state, 3.0f);
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_speed_update_timestamp = now;
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}
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void TECS::_update_speed_setpoint()
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{
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// Set the airspeed demand to the minimum value if an underspeed or
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// or a uncontrolled descent condition exists to maximise climb rate
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if ((_uncommanded_descent_recovery) || (_underspeed_detected)) {
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_TAS_setpoint = _TAS_min;
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}
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_TAS_setpoint = constrain(_TAS_setpoint, _TAS_min, _TAS_max);
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// Apply limits on the demanded rate of change of speed based based on physical performance limits
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// with a 50% margin to allow the total energy controller to correct for errors.
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float velRateMax;
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float velRateMin;
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if ((_uncommanded_descent_recovery) || (_underspeed_detected)) {
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velRateMax = 0.5f * _STE_rate_max / _tas_state;
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velRateMin = 0.5f * _STE_rate_min / _tas_state;
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} else {
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velRateMax = 0.5f * _STE_rate_max / _tas_state;
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velRateMin = 0.5f * _STE_rate_min / _tas_state;
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}
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_TAS_setpoint_adj = constrain(_TAS_setpoint, _TAS_min, _TAS_max);
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// calculate the demanded rate of change of speed proportional to speed error
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// and apply performance limits
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_TAS_rate_setpoint = constrain((_TAS_setpoint_adj - _tas_state) * _speed_error_gain, velRateMin, velRateMax);
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}
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void TECS::_update_height_setpoint(float desired, float state)
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{
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// Detect first time through and initialize previous value to demand
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if (PX4_ISFINITE(desired) && fabsf(_hgt_setpoint_in_prev) < 0.1f) {
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_hgt_setpoint_in_prev = desired;
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}
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// Apply a 2 point moving average to demanded height to reduce
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// intersampling noise effects.
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if (PX4_ISFINITE(desired)) {
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_hgt_setpoint = 0.5f * (desired + _hgt_setpoint_in_prev);
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} else {
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_hgt_setpoint = _hgt_setpoint_in_prev;
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}
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_hgt_setpoint_in_prev = _hgt_setpoint;
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// Apply a rate limit to respect vehicle performance limitations
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if ((_hgt_setpoint - _hgt_setpoint_prev) > (_max_climb_rate * _dt)) {
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_hgt_setpoint = _hgt_setpoint_prev + _max_climb_rate * _dt;
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} else if ((_hgt_setpoint - _hgt_setpoint_prev) < (-_max_sink_rate * _dt)) {
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_hgt_setpoint = _hgt_setpoint_prev - _max_sink_rate * _dt;
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}
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_hgt_setpoint_prev = _hgt_setpoint;
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// Apply a first order noise filter
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_hgt_setpoint_adj = 0.1f * _hgt_setpoint + 0.9f * _hgt_setpoint_adj_prev;
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// Calculate the demanded climb rate proportional to height error plus a feedforward term to provide
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// tight tracking during steady climb and descent manouvres.
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_hgt_rate_setpoint = (_hgt_setpoint_adj - state) * _height_error_gain + _height_setpoint_gain_ff * (_hgt_setpoint_adj - _hgt_setpoint_adj_prev) / _dt;
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_hgt_setpoint_adj_prev = _hgt_setpoint_adj;
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// Limit the rate of change of height demand to respect vehicle performance limits
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if (_hgt_rate_setpoint > _max_climb_rate) {
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_hgt_rate_setpoint = _max_climb_rate;
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} else if (_hgt_rate_setpoint < -_max_sink_rate) {
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_hgt_rate_setpoint = -_max_sink_rate;
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}
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}
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void TECS::_detect_underspeed()
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{
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if (!_detect_underspeed_enabled) {
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_underspeed_detected = false;
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return;
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}
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if (((_tas_state < _TAS_min * 0.9f) && (_throttle_setpoint >= _throttle_setpoint_max * 0.95f)) || ((_vert_pos_state < _hgt_setpoint_adj)
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&& _underspeed_detected)) {
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_underspeed_detected = true;
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} else {
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_underspeed_detected = false;
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}
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}
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void TECS::_update_energy_estimates()
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{
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// Calculate specific energy demands in units of (m**2/sec**2)
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_SPE_setpoint = _hgt_setpoint_adj * CONSTANTS_ONE_G; // potential energy
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_SKE_setpoint = 0.5f * _TAS_setpoint_adj * _TAS_setpoint_adj; // kinetic energy
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// Calculate specific energy rate demands in units of (m**2/sec**3)
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_SPE_rate_setpoint = _hgt_rate_setpoint * CONSTANTS_ONE_G; // potential energy rate of change
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_SKE_rate_setpoint = _tas_state * _TAS_rate_setpoint; // kinetic energy rate of change
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// Calculate specific energies in units of (m**2/sec**2)
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_SPE_estimate = _vert_pos_state * CONSTANTS_ONE_G; // potential energy
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_SKE_estimate = 0.5f * _tas_state * _tas_state; // kinetic energy
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// Calculate specific energy rates in units of (m**2/sec**3)
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_SPE_rate = _vert_vel_state * CONSTANTS_ONE_G; // potential ernegy rate of change
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_SKE_rate = _tas_state * _speed_derivative;// kinetic energy rate of change
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}
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void TECS::_update_throttle_setpoint(const float throttle_cruise, const math::Matrix<3, 3> &rotMat)
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{
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// Calculate total energy error
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_STE_error = _SPE_setpoint - _SPE_estimate + _SKE_setpoint - _SKE_estimate;
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// Calculate demanded rate of change of total energy, respecting vehicle limits
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float STE_rate_setpoint = constrain((_SPE_rate_setpoint + _SKE_rate_setpoint), _STE_rate_min, _STE_rate_max);
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// Calculate the total energy rate error, applying a first order IIR filter
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// to reduce the effect of accelerometer noise
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_STE_rate_error = 0.2f * (STE_rate_setpoint - _SPE_rate - _SKE_rate) + 0.8f * _STE_rate_error;
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// Calculate the throttle demand
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if (_underspeed_detected) {
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// always use full throttle to recover from an underspeed condition
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_throttle_setpoint = 1.0f;
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} else {
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// Adjust the demanded total energy rate to compensate for induced drag rise in turns.
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// Assume induced drag scales linearly with normal load factor.
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// The additional normal load factor is given by (1/cos(bank angle) - 1)
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float cosPhi = sqrtf((rotMat(0, 1) * rotMat(0, 1)) + (rotMat(1, 1) * rotMat(1, 1)));
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STE_rate_setpoint = STE_rate_setpoint + _load_factor_correction * (1.0f / constrain(cosPhi, 0.1f, 1.0f) - 1.0f);
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// Calculate a predicted throttle from the demanded rate of change of energy, using the cruise throttle
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// as the starting point. Assume:
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// Specific total energy rate = _STE_rate_max is acheived when throttle is set to to _throttle_setpoint_max
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// Specific total energy rate = 0 at cruise throttle
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// Specific total energy rate = _STE_rate_min is acheived when throttle is set to to _throttle_setpoint_min
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float throttle_predicted = 0.0f;
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if (STE_rate_setpoint >= 0) {
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// throttle is between cruise and maximum
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throttle_predicted = throttle_cruise + STE_rate_setpoint / _STE_rate_max * (_throttle_setpoint_max - throttle_cruise);
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|
||||
} else {
|
||||
// throttle is between cruise and minimum
|
||||
throttle_predicted = throttle_cruise + STE_rate_setpoint / _STE_rate_min * (_throttle_setpoint_min - throttle_cruise);
|
||||
|
||||
}
|
||||
|
||||
// Calculate gain scaler from specific energy error to throttle
|
||||
float STE_to_throttle = 1.0f / (_throttle_time_constant * (_STE_rate_max - _STE_rate_min));
|
||||
|
||||
// Add proportional and derivative control feedback to the predicted throttle and constrain to throttle limits
|
||||
_throttle_setpoint = (_STE_error + _STE_rate_error * _throttle_damping_gain) * STE_to_throttle + throttle_predicted;
|
||||
_throttle_setpoint = constrain(_throttle_setpoint, _throttle_setpoint_min, _throttle_setpoint_max);
|
||||
|
||||
// Rate limit the throttle demand
|
||||
if (fabsf(_throttle_slewrate) > 0.01f) {
|
||||
float throttle_increment_limit = _dt * (_throttle_setpoint_max - _throttle_setpoint_min) * _throttle_slewrate;
|
||||
_throttle_setpoint = constrain(_throttle_setpoint, _last_throttle_setpoint - throttle_increment_limit, _last_throttle_setpoint + throttle_increment_limit);
|
||||
}
|
||||
_last_throttle_setpoint = _throttle_setpoint;
|
||||
|
||||
// Calculate throttle integrator state upper and lower limits with allowance for
|
||||
// 10% throttle saturation to accoodate noise on the demand
|
||||
float integ_state_max = (_throttle_setpoint_max - _throttle_setpoint + 0.1f);
|
||||
float integ_state_min = (_throttle_setpoint_min - _throttle_setpoint - 0.1f);
|
||||
|
||||
// Calculate a throttle demand from the integrated total energy error
|
||||
// This will be added to the total throttle demand to compensate for steady state errors
|
||||
_throttle_integ_state = _throttle_integ_state + (_STE_error * _integrator_gain) * _dt * STE_to_throttle;
|
||||
|
||||
if (_climbout_mode_active) {
|
||||
// During climbout, set the integrator to maximum throttle to prevent transient throttle drop
|
||||
// at end of climbout when we traniton to closed loop throttle control
|
||||
_throttle_integ_state = integ_state_max;
|
||||
|
||||
} else {
|
||||
// Respect integrator limits during closed loop operation.
|
||||
_throttle_integ_state = constrain(_throttle_integ_state, integ_state_min, integ_state_max);
|
||||
|
||||
}
|
||||
|
||||
if (airspeed_sensor_enabled()) {
|
||||
// Add the integrator feedback during closed loop operation with an airspeed sensor
|
||||
_throttle_setpoint = _throttle_setpoint + _throttle_integ_state;
|
||||
|
||||
} else {
|
||||
// when flying without an airspeed sensor, use the predicted throttle only
|
||||
_throttle_setpoint = throttle_predicted;
|
||||
|
||||
}
|
||||
|
||||
_throttle_setpoint = constrain(_throttle_setpoint, _throttle_setpoint_min, _throttle_setpoint_max);
|
||||
}
|
||||
}
|
||||
|
||||
void TECS::_detect_uncommanded_descent()
|
||||
{
|
||||
/*
|
||||
* This function detects a condition that can occur when the demanded airspeed is greater than the
|
||||
* aircraft can achieve in level flight. When this occurs, the vehicle will continue to reduce height
|
||||
* while attempting to maintain speed.
|
||||
*/
|
||||
|
||||
// Calculate rate of change of total specific energy
|
||||
float STE_rate = _SPE_rate + _SKE_rate;
|
||||
|
||||
// If total energy is very low and reducing, throttle is high, and we are not in an underspeed condition, then enter uncommanded descent recovery mode
|
||||
bool enter_mode = !_uncommanded_descent_recovery && !_underspeed_detected && (_STE_error > 200.0f) && (STE_rate < 0.0f) && (_throttle_setpoint >= _throttle_setpoint_max * 0.9f);
|
||||
|
||||
// If we enter an underspeed cindition or recover the required total energy, then exit uncommanded descent recovery mode
|
||||
bool exit_mode = _uncommanded_descent_recovery && (_underspeed_detected || (_STE_error < 0.0f));
|
||||
if (enter_mode) {
|
||||
_uncommanded_descent_recovery = true;
|
||||
|
||||
} else if (exit_mode) {
|
||||
_uncommanded_descent_recovery = false;
|
||||
|
||||
}
|
||||
}
|
||||
|
||||
void TECS::_update_pitch_setpoint()
|
||||
{
|
||||
/*
|
||||
* The SKE_weighting variable controls how speed and height control are prioritised by the pitch demand calculation.
|
||||
* A weighting of 1 givea equal speed and height priority
|
||||
* A weighting of 0 gives 100% priority to height control and must be used when no airspeed measurement is available.
|
||||
* A weighting of 2 provides 100% priority to speed control and is used when:
|
||||
* a) an underspeed condition is detected.
|
||||
* b) during climbout where a minimum pitch angle has been set to ensure height is gained. If the airspeed
|
||||
* rises above the demanded value, the pitch angle demand is increased by the TECS controller to prevent the vehicle overspeeding.
|
||||
* The weighting can be adjusted between 0 and 2 depending on speed and height accuracy requirements.
|
||||
*/
|
||||
|
||||
// Calculate the weighting applied to control of specific kinetic energy error
|
||||
float SKE_weighting = constrain(_pitch_speed_weight, 0.0f, 2.0f);
|
||||
|
||||
if ((_underspeed_detected || _climbout_mode_active) && airspeed_sensor_enabled()) {
|
||||
SKE_weighting = 2.0f;
|
||||
|
||||
} else if (!airspeed_sensor_enabled()) {
|
||||
SKE_weighting = 0.0f;
|
||||
}
|
||||
|
||||
// Calculate the weighting applied to control of specific potential energy error
|
||||
float SPE_weighting = 2.0f - SKE_weighting;
|
||||
|
||||
// Calculate the specific energy balance demand which specifies how the available total
|
||||
// energy should be allocated to speed (kinetic energy) and height (potential energy)
|
||||
float SEB_setpoint = _SPE_setpoint * SPE_weighting - _SKE_setpoint * SKE_weighting;
|
||||
|
||||
// Calculate the specific energy balance rate demand
|
||||
float SEB_rate_setpoint = _SPE_rate_setpoint * SPE_weighting - _SKE_rate_setpoint * SKE_weighting;
|
||||
|
||||
// Calculate the specific energy balance and balance rate error
|
||||
_SEB_error = SEB_setpoint - (_SPE_estimate * SPE_weighting - _SKE_estimate * SKE_weighting);
|
||||
_SEB_rate_error = SEB_rate_setpoint - (_SPE_rate * SPE_weighting - _SKE_rate * SKE_weighting);
|
||||
|
||||
// Calculate derivative from change in climb angle to rate of change of specific energy balance
|
||||
float climb_angle_to_SEB_rate = _tas_state * _pitch_time_constant * CONSTANTS_ONE_G;
|
||||
|
||||
// Calculate pitch integrator input term
|
||||
float pitch_integ_input = _SEB_error * _integrator_gain;
|
||||
|
||||
// Prevent the integrator changing in a direction that will increase pitch demand saturation
|
||||
// Decay the integrator at the control loop time constant if the pitch demand fromthe previous time step is saturated
|
||||
if (_pitch_setpoint_unc > _pitch_setpoint_max) {
|
||||
pitch_integ_input = min(pitch_integ_input, min((_pitch_setpoint_max - _pitch_setpoint_unc) * climb_angle_to_SEB_rate / _pitch_time_constant, 0.0f));
|
||||
|
||||
} else if (_pitch_setpoint_unc < _pitch_setpoint_min) {
|
||||
pitch_integ_input = max(pitch_integ_input, max((_pitch_setpoint_min - _pitch_setpoint_unc) * climb_angle_to_SEB_rate / _pitch_time_constant, 0.0f));
|
||||
}
|
||||
|
||||
// Update the pitch integrator state
|
||||
_pitch_integ_state = _pitch_integ_state + pitch_integ_input * _dt;
|
||||
|
||||
// Calculate a specific energy correction that doesn't include the integrator contribution
|
||||
float SEB_correction = _SEB_error + _SEB_rate_error * _pitch_damping_gain + SEB_rate_setpoint * _pitch_time_constant;
|
||||
|
||||
// During climbout, bias the demanded pitch angle so that a zero speed error produces a pitch angle
|
||||
// demand equal to the minimum pitch angle set by the mission plan. This prevents the integrator
|
||||
// having to catch up before the nose can be raised to reduce excess speed during climbout.
|
||||
if (_climbout_mode_active) {
|
||||
SEB_correction += _pitch_setpoint_min * climb_angle_to_SEB_rate;
|
||||
}
|
||||
|
||||
// Sum the correction terms and convert to a pitch angle demand. This calculation assumes:
|
||||
// a) The climb angle follows pitch angle with a lag that is small enough not to destabilise the control loop.
|
||||
// b) The offset between climb angle and pitch angle (angle of attack) is constant, excluding the effect of
|
||||
// pitch transients due to control action or turbulence.
|
||||
_pitch_setpoint_unc = (SEB_correction + _pitch_integ_state) / climb_angle_to_SEB_rate;
|
||||
_pitch_setpoint = constrain(_pitch_setpoint_unc, _pitch_setpoint_min, _pitch_setpoint_max);
|
||||
|
||||
// Comply with the specified vertical acceleration limit by applying a pitch rate limit
|
||||
float ptchRateIncr = _dt * _vert_accel_limit / _tas_state;
|
||||
|
||||
if ((_pitch_setpoint - _last_pitch_setpoint) > ptchRateIncr) {
|
||||
_pitch_setpoint = _last_pitch_setpoint + ptchRateIncr;
|
||||
|
||||
} else if ((_pitch_setpoint - _last_pitch_setpoint) < -ptchRateIncr) {
|
||||
_pitch_setpoint = _last_pitch_setpoint - ptchRateIncr;
|
||||
}
|
||||
|
||||
_last_pitch_setpoint = _pitch_setpoint;
|
||||
}
|
||||
|
||||
void TECS::_initialize_states(float pitch, float throttle_cruise, float baro_altitude, float pitch_min_climbout,
|
||||
float EAS2TAS)
|
||||
{
|
||||
if (_pitch_update_timestamp == 0 || _dt > DT_MAX || !_in_air || !_states_initalized) {
|
||||
// On first time through or when not using TECS of if there has been a large time slip,
|
||||
// states must be reset to allow filters to a clean start
|
||||
_vert_accel_state = 0.0f;
|
||||
_vert_vel_state = 0.0f;
|
||||
_vert_pos_state = baro_altitude;
|
||||
_tas_rate_state = 0.0f;
|
||||
_tas_state = _EAS * EAS2TAS;
|
||||
_throttle_integ_state = 0.0f;
|
||||
_pitch_integ_state = 0.0f;
|
||||
_last_throttle_setpoint = throttle_cruise;
|
||||
_last_pitch_setpoint = constrain(pitch, _pitch_setpoint_min, _pitch_setpoint_max);
|
||||
_pitch_setpoint_unc = _last_pitch_setpoint;
|
||||
_hgt_setpoint_adj_prev = baro_altitude;
|
||||
_hgt_setpoint_adj = _hgt_setpoint_adj_prev;
|
||||
_hgt_setpoint_prev = _hgt_setpoint_adj_prev;
|
||||
_hgt_setpoint_in_prev = _hgt_setpoint_adj_prev;
|
||||
_TAS_setpoint_last = _EAS * EAS2TAS;
|
||||
_TAS_setpoint_adj = _TAS_setpoint_last;
|
||||
_underspeed_detected = false;
|
||||
_uncommanded_descent_recovery = false;
|
||||
_STE_rate_error = 0.0f;
|
||||
|
||||
if (_dt > DT_MAX || _dt < DT_MIN) {
|
||||
_dt = DT_DEFAULT;
|
||||
}
|
||||
|
||||
} else if (_climbout_mode_active) {
|
||||
// During climbout use the lower pitch angle limit specified by the
|
||||
// calling controller
|
||||
_pitch_setpoint_min = pitch_min_climbout;
|
||||
|
||||
// throttle lower limit is set to a value that prevents throttle reduction
|
||||
_throttle_setpoint_min = _throttle_setpoint_max - 0.01f;
|
||||
|
||||
// height demand and associated states are set to track the measured height
|
||||
_hgt_setpoint_adj_prev = baro_altitude;
|
||||
_hgt_setpoint_adj = _hgt_setpoint_adj_prev;
|
||||
_hgt_setpoint_prev = _hgt_setpoint_adj_prev;
|
||||
|
||||
// airspeed demand states are set to track the measured airspeed
|
||||
_TAS_setpoint_last = _EAS * EAS2TAS;
|
||||
_TAS_setpoint_adj = _EAS * EAS2TAS;
|
||||
|
||||
// disable speed and decent error condition checks
|
||||
_underspeed_detected = false;
|
||||
_uncommanded_descent_recovery = false;
|
||||
}
|
||||
|
||||
_states_initalized = true;
|
||||
}
|
||||
|
||||
void TECS::_update_STE_rate_lim()
|
||||
{
|
||||
// Calculate the specific total energy upper rate limits from the max throttle climb rate
|
||||
_STE_rate_max = _max_climb_rate * CONSTANTS_ONE_G;
|
||||
|
||||
// Calculate the specific total energy lower rate limits from the min throttle sink rate
|
||||
_STE_rate_min = - _min_sink_rate * CONSTANTS_ONE_G;
|
||||
}
|
||||
|
||||
void TECS::update_pitch_throttle(const math::Matrix<3, 3> &rotMat, float pitch, float baro_altitude, float hgt_setpoint,
|
||||
float EAS_setpoint, float indicated_airspeed, float EAS2TAS, bool climb_out_setpoint, float pitch_min_climbout,
|
||||
float throttle_min, float throttle_max, float throttle_cruise, float pitch_limit_min, float pitch_limit_max)
|
||||
{
|
||||
|
||||
// Calculate the time since last update (seconds)
|
||||
uint64_t now = ecl_absolute_time();
|
||||
_dt = max((now - _pitch_update_timestamp), UINT64_C(0)) * 1.0e-6f;
|
||||
|
||||
// Set class variables from inputs
|
||||
_throttle_setpoint_max = throttle_max;
|
||||
_throttle_setpoint_min = throttle_min;
|
||||
_pitch_setpoint_max = pitch_limit_max;
|
||||
_pitch_setpoint_min = pitch_limit_min;
|
||||
_climbout_mode_active = climb_out_setpoint;
|
||||
|
||||
// Initialize selected states and variables as required
|
||||
_initialize_states(pitch, throttle_cruise, baro_altitude, pitch_min_climbout, EAS2TAS);
|
||||
|
||||
// Don't run TECS control agorithms when not in flight
|
||||
if (!_in_air) {
|
||||
return;
|
||||
}
|
||||
|
||||
// Update the true airspeed state estimate
|
||||
_update_speed_states(EAS_setpoint, indicated_airspeed, EAS2TAS);
|
||||
|
||||
// Calculate rate limits for specific total energy
|
||||
_update_STE_rate_lim();
|
||||
|
||||
// Detect an underspeed condition
|
||||
_detect_underspeed();
|
||||
|
||||
// Detect an uncommanded descent caused by an unachievable airspeed demand
|
||||
_detect_uncommanded_descent();
|
||||
|
||||
// Calculate the demanded true airspeed
|
||||
_update_speed_setpoint();
|
||||
|
||||
// Calculate the demanded height
|
||||
_update_height_setpoint(hgt_setpoint, baro_altitude);
|
||||
|
||||
// Calculate the specific energy values required by the control loop
|
||||
_update_energy_estimates();
|
||||
|
||||
// Calculate the throttle demand
|
||||
_update_throttle_setpoint(throttle_cruise, rotMat);
|
||||
|
||||
// Calculate the pitch demand
|
||||
_update_pitch_setpoint();
|
||||
|
||||
// Update time stamps
|
||||
_pitch_update_timestamp = now;
|
||||
|
||||
// Set TECS mode for next frame
|
||||
if (_underspeed_detected) {
|
||||
_tecs_mode = ECL_TECS_MODE_UNDERSPEED;
|
||||
|
||||
} else if (_uncommanded_descent_recovery) {
|
||||
_tecs_mode = ECL_TECS_MODE_BAD_DESCENT;
|
||||
|
||||
} else if (_climbout_mode_active) {
|
||||
_tecs_mode = ECL_TECS_MODE_CLIMBOUT;
|
||||
|
||||
} else {
|
||||
// This is the default operation mode
|
||||
_tecs_mode = ECL_TECS_MODE_NORMAL;
|
||||
}
|
||||
|
||||
}
|
||||
|
|
@ -0,0 +1,488 @@
|
|||
/****************************************************************************
|
||||
*
|
||||
* Copyright (c) 2017 Estimation and Control Library (ECL). 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 ECL 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 tecs.cpp
|
||||
*
|
||||
* @author Paul Riseborough
|
||||
*/
|
||||
|
||||
#pragma once
|
||||
|
||||
#include <mathlib/mathlib.h>
|
||||
#include <stdint.h>
|
||||
|
||||
class __EXPORT TECS
|
||||
{
|
||||
public:
|
||||
TECS() :
|
||||
_state_update_timestamp(0),
|
||||
_speed_update_timestamp(0),
|
||||
_pitch_update_timestamp(0),
|
||||
_hgt_estimate_freq(0.0f),
|
||||
_tas_estimate_freq(0.0f),
|
||||
_max_climb_rate(2.0f),
|
||||
_min_sink_rate(1.0f),
|
||||
_max_sink_rate(2.0f),
|
||||
_pitch_time_constant(5.0f),
|
||||
_throttle_time_constant(8.0f),
|
||||
_pitch_damping_gain(0.0f),
|
||||
_throttle_damping_gain(0.0f),
|
||||
_integrator_gain(0.0f),
|
||||
_vert_accel_limit(0.0f),
|
||||
_load_factor_correction(0.0f),
|
||||
_pitch_speed_weight(1.0f),
|
||||
_height_error_gain(0.0f),
|
||||
_height_setpoint_gain_ff(0.0f),
|
||||
_speed_error_gain(0.0f),
|
||||
_throttle_setpoint(0.0f),
|
||||
_pitch_setpoint(0.0f),
|
||||
_vert_accel_state(0.0f),
|
||||
_vert_vel_state(0.0f),
|
||||
_vert_pos_state(0.0f),
|
||||
_tas_rate_state(0.0f),
|
||||
_tas_state(0.0f),
|
||||
_throttle_integ_state(0.0f),
|
||||
_pitch_integ_state(0.0f),
|
||||
_last_throttle_setpoint(0.0f),
|
||||
_last_pitch_setpoint(0.0f),
|
||||
_speed_derivative(0.0f),
|
||||
_EAS(0.0f),
|
||||
_TAS_max(30.0f),
|
||||
_TAS_min(3.0f),
|
||||
_TAS_setpoint(0.0f),
|
||||
_TAS_setpoint_last(0.0f),
|
||||
_EAS_setpoint(0.0f),
|
||||
_TAS_setpoint_adj(0.0f),
|
||||
_TAS_rate_setpoint(0.0f),
|
||||
_indicated_airspeed_min(3.0f),
|
||||
_indicated_airspeed_max(30.0f),
|
||||
_hgt_setpoint(0.0f),
|
||||
_hgt_setpoint_in_prev(0.0f),
|
||||
_hgt_setpoint_prev(0.0f),
|
||||
_hgt_setpoint_adj(0.0f),
|
||||
_hgt_setpoint_adj_prev(0.0f),
|
||||
_hgt_rate_setpoint(0.0f),
|
||||
_pitch_setpoint_unc(0.0f),
|
||||
_STE_rate_max(0.0f),
|
||||
_STE_rate_min(0.0f),
|
||||
_throttle_setpoint_max(0.0f),
|
||||
_throttle_setpoint_min(0.0f),
|
||||
_pitch_setpoint_max(0.5f),
|
||||
_pitch_setpoint_min(-0.5f),
|
||||
_throttle_slewrate(0.0f),
|
||||
_SPE_setpoint(0.0f),
|
||||
_SKE_setpoint(0.0f),
|
||||
_SPE_rate_setpoint(0.0f),
|
||||
_SKE_rate_setpoint(0.0f),
|
||||
_SPE_estimate(0.0f),
|
||||
_SKE_estimate(0.0f),
|
||||
_SPE_rate(0.0f),
|
||||
_SKE_rate(0.0f),
|
||||
_STE_error(0.0f),
|
||||
_STE_rate_error(0.0f),
|
||||
_SEB_error(0.0f),
|
||||
_SEB_rate_error(0.0f),
|
||||
_dt(0.02f),
|
||||
_underspeed_detected(false),
|
||||
_detect_underspeed_enabled(true),
|
||||
_uncommanded_descent_recovery(false),
|
||||
_climbout_mode_active(false),
|
||||
_airspeed_enabled(false),
|
||||
_states_initalized(false),
|
||||
_in_air(false)
|
||||
{
|
||||
}
|
||||
|
||||
/**
|
||||
* Get the current airspeed status
|
||||
*
|
||||
* @return true if airspeed is enabled for control
|
||||
*/
|
||||
bool airspeed_sensor_enabled()
|
||||
{
|
||||
return _airspeed_enabled;
|
||||
}
|
||||
|
||||
/**
|
||||
* Set the airspeed enable state
|
||||
*/
|
||||
void enable_airspeed(bool enabled)
|
||||
{
|
||||
_airspeed_enabled = enabled;
|
||||
}
|
||||
|
||||
/**
|
||||
* Updates the following vehicle kineamtic state estimates:
|
||||
* Vertical position, velocity and acceleration.
|
||||
* Speed derivative
|
||||
* Must be called prior to udating tecs control loops
|
||||
* Must be called at 50Hz or greater
|
||||
*/
|
||||
void update_vehicle_state_estimates(float airspeed, const math::Matrix<3, 3> &rotMat,
|
||||
const math::Vector<3> &accel_body, bool altitude_lock, bool in_air,
|
||||
float altitude, bool vz_valid, float vz, float az);
|
||||
|
||||
/**
|
||||
* Update the control loop calculations
|
||||
*/
|
||||
void update_pitch_throttle(const math::Matrix<3, 3> &rotMat, float pitch, float baro_altitude, float hgt_setpoint,
|
||||
float EAS_setpoint, float indicated_airspeed, float eas_to_tas, bool climb_out_setpoint, float pitch_min_climbout,
|
||||
float throttle_min, float _throttle_setpoint_max, float throttle_cruise,
|
||||
float pitch_limit_min, float pitch_limit_max);
|
||||
|
||||
float get_throttle_setpoint(void) { return _throttle_setpoint; }
|
||||
float get_pitch_setpoint() { return _pitch_setpoint; }
|
||||
float get_speed_weight() { return _pitch_speed_weight; }
|
||||
|
||||
void reset_state()
|
||||
{
|
||||
_states_initalized = false;
|
||||
}
|
||||
|
||||
enum ECL_TECS_MODE {
|
||||
ECL_TECS_MODE_NORMAL = 0,
|
||||
ECL_TECS_MODE_UNDERSPEED,
|
||||
ECL_TECS_MODE_BAD_DESCENT,
|
||||
ECL_TECS_MODE_CLIMBOUT
|
||||
};
|
||||
|
||||
enum ECL_TECS_MODE _tecs_mode;
|
||||
|
||||
void set_time_const(float time_const)
|
||||
{
|
||||
_pitch_time_constant = time_const;
|
||||
}
|
||||
|
||||
void set_time_const_throt(float time_const_throt)
|
||||
{
|
||||
_throttle_time_constant = time_const_throt;
|
||||
}
|
||||
|
||||
void set_min_sink_rate(float rate)
|
||||
{
|
||||
_min_sink_rate = rate;
|
||||
}
|
||||
|
||||
void set_max_sink_rate(float sink_rate)
|
||||
{
|
||||
_max_sink_rate = sink_rate;
|
||||
}
|
||||
|
||||
void set_max_climb_rate(float climb_rate)
|
||||
{
|
||||
_max_climb_rate = climb_rate;
|
||||
}
|
||||
|
||||
void set_throttle_damp(float throttle_damp)
|
||||
{
|
||||
_throttle_damping_gain = throttle_damp;
|
||||
}
|
||||
|
||||
void set_integrator_gain(float gain)
|
||||
{
|
||||
_integrator_gain = gain;
|
||||
}
|
||||
|
||||
void set_vertical_accel_limit(float limit)
|
||||
{
|
||||
_vert_accel_limit = limit;
|
||||
}
|
||||
|
||||
void set_height_comp_filter_omega(float omega)
|
||||
{
|
||||
_hgt_estimate_freq = omega;
|
||||
}
|
||||
|
||||
void set_speed_comp_filter_omega(float omega)
|
||||
{
|
||||
_tas_estimate_freq = omega;
|
||||
}
|
||||
|
||||
void set_roll_throttle_compensation(float compensation)
|
||||
{
|
||||
_load_factor_correction = compensation;
|
||||
}
|
||||
|
||||
void set_speed_weight(float weight)
|
||||
{
|
||||
_pitch_speed_weight = weight;
|
||||
}
|
||||
|
||||
void set_pitch_damping(float damping)
|
||||
{
|
||||
_pitch_damping_gain = damping;
|
||||
}
|
||||
|
||||
void set_throttle_slewrate(float slewrate)
|
||||
{
|
||||
_throttle_slewrate = slewrate;
|
||||
}
|
||||
|
||||
void set_indicated_airspeed_min(float airspeed)
|
||||
{
|
||||
_indicated_airspeed_min = airspeed;
|
||||
}
|
||||
|
||||
void set_indicated_airspeed_max(float airspeed)
|
||||
{
|
||||
_indicated_airspeed_max = airspeed;
|
||||
}
|
||||
|
||||
void set_heightrate_p(float heightrate_p)
|
||||
{
|
||||
_height_error_gain = heightrate_p;
|
||||
}
|
||||
|
||||
void set_heightrate_ff(float heightrate_ff)
|
||||
{
|
||||
_height_setpoint_gain_ff = heightrate_ff;
|
||||
}
|
||||
|
||||
void set_speedrate_p(float speedrate_p)
|
||||
{
|
||||
_speed_error_gain = speedrate_p;
|
||||
}
|
||||
|
||||
void set_detect_underspeed_enabled(bool enabled)
|
||||
{
|
||||
_detect_underspeed_enabled = enabled;
|
||||
}
|
||||
|
||||
float hgt_setpoint_adj() { return _hgt_setpoint_adj; }
|
||||
|
||||
float vert_pos_state() { return _vert_pos_state; }
|
||||
|
||||
float TAS_setpoint_adj() { return _TAS_setpoint_adj; }
|
||||
|
||||
float tas_state() { return _tas_state; }
|
||||
|
||||
float hgt_rate_setpoint() { return _hgt_rate_setpoint; }
|
||||
|
||||
float vert_vel_state() { return _vert_vel_state; }
|
||||
|
||||
float TAS_rate_setpoint() { return _TAS_rate_setpoint; }
|
||||
|
||||
float speed_derivative() { return _speed_derivative; }
|
||||
|
||||
float STE_error() { return _STE_error; }
|
||||
|
||||
float STE_rate_error() { return _STE_rate_error; }
|
||||
|
||||
float SEB_error() { return _SEB_error; }
|
||||
|
||||
float SEB_rate_error() { return _SEB_rate_error; }
|
||||
|
||||
float throttle_integ_state() { return _throttle_integ_state; }
|
||||
|
||||
float pitch_integ_state() { return _pitch_integ_state; }
|
||||
|
||||
int tecs_mode() { return _tecs_mode; }
|
||||
|
||||
uint64_t timestamp() { return _pitch_update_timestamp; }
|
||||
|
||||
/**
|
||||
* Handle the altitude reset
|
||||
*
|
||||
* If the estimation system resets the height in one discrete step this
|
||||
* will gracefully even out the reset over time.
|
||||
*/
|
||||
void handle_alt_step(float delta_alt, float altitude)
|
||||
{
|
||||
// add height reset delta to all variables involved
|
||||
// in filtering the demanded height
|
||||
_hgt_setpoint_in_prev += delta_alt;
|
||||
_hgt_setpoint_prev += delta_alt;
|
||||
_hgt_setpoint_adj_prev += delta_alt;
|
||||
|
||||
// reset height states
|
||||
_vert_pos_state = altitude;
|
||||
_vert_accel_state = 0.0f;
|
||||
_vert_vel_state = 0.0f;
|
||||
}
|
||||
|
||||
private:
|
||||
|
||||
// timestamps
|
||||
uint64_t _state_update_timestamp; ///< last timestamp of the 50 Hz function call
|
||||
uint64_t _speed_update_timestamp; ///< last timestamp of the speed function call
|
||||
uint64_t _pitch_update_timestamp; ///< last timestamp of the pitch function call
|
||||
|
||||
// controller parameters
|
||||
float _hgt_estimate_freq; ///< cross-over frequency of the height rate complementary filter (rad/sec)
|
||||
float _tas_estimate_freq; ///< cross-over frequency of the true airspeed complementary filter (rad/sec)
|
||||
float _max_climb_rate; ///< climb rate produced by max allowed throttle (m/sec)
|
||||
float _min_sink_rate; ///< sink rate produced by min allowed throttle (m/sec)
|
||||
float _max_sink_rate; ///< maximum safe sink rate (m/sec)
|
||||
float _pitch_time_constant; ///< control time constant used by the pitch demand calculation (sec)
|
||||
float _throttle_time_constant; ///< control time constant used by the throttle demand calculation (sec)
|
||||
float _pitch_damping_gain; ///< damping gain of the pitch demand calculation (sec)
|
||||
float _throttle_damping_gain; ///< damping gain of the throttle demand calculation (sec)
|
||||
float _integrator_gain; ///< integrator gain used by the throttle and pitch demand calculation
|
||||
float _vert_accel_limit; ///< magnitude of the maximum vertical acceleration allowed (m/sec**2)
|
||||
float _load_factor_correction; ///< gain from normal load factor increase to total energy rate demand (m**2/sec**3)
|
||||
float _pitch_speed_weight; ///< speed control weighting used by pitch demand calculation
|
||||
float _height_error_gain; ///< gain from height error to demanded climb rate (1/sec)
|
||||
float _height_setpoint_gain_ff; ///< gain from height demand derivative to demanded climb rate
|
||||
float _speed_error_gain; ///< gain from speed error to demanded speed rate (1/sec)
|
||||
|
||||
// controller outputs
|
||||
float _throttle_setpoint; ///< normalized throttle demand (0..1)
|
||||
float _pitch_setpoint; ///< pitch angle demand (radians)
|
||||
|
||||
// complimentary filter states
|
||||
float _vert_accel_state; ///< complimentary filter state - height second derivative (m/sec**2)
|
||||
float _vert_vel_state; ///< complimentary filter state - height rate (m/sec)
|
||||
float _vert_pos_state; ///< complimentary filter state - height (m)
|
||||
float _tas_rate_state; ///< complimentary filter state - true airspeed first derivative (m/sec**2)
|
||||
float _tas_state; ///< complimentary filter state - true airspeed (m/sec)
|
||||
|
||||
// controller states
|
||||
float _throttle_integ_state; ///< throttle integrator state
|
||||
float _pitch_integ_state; ///< pitch integrator state (rad)
|
||||
float _last_throttle_setpoint; ///< throttle demand rate limiter state (1/sec)
|
||||
float _last_pitch_setpoint; ///< pitch demand rate limiter state (rad/sec)
|
||||
float _speed_derivative; ///< rate of change of speed along X axis (m/sec**2)
|
||||
|
||||
// speed demand calculations
|
||||
float _EAS; ///< equivalent airspeed (m/sec)
|
||||
float _TAS_max; ///< true airpeed demand upper limit (m/sec)
|
||||
float _TAS_min; ///< true airpeed demand lower limit (m/sec)
|
||||
float _TAS_setpoint; ///< current airpeed demand (m/sec)
|
||||
float _TAS_setpoint_last; ///< previous true airpeed demand (m/sec)
|
||||
float _EAS_setpoint; ///< Equivalent airspeed demand (m/sec)
|
||||
float _TAS_setpoint_adj; ///< true airspeed demand tracked by the TECS algorithm (m/sec)
|
||||
float _TAS_rate_setpoint; ///< true airspeed rate demand tracked by the TECS algorithm (m/sec**2)
|
||||
float _indicated_airspeed_min; ///< equivalent airspeed demand lower limit (m/sec)
|
||||
float _indicated_airspeed_max; ///< equivalent airspeed demand upper limit (m/sec)
|
||||
|
||||
// height demand calculations
|
||||
float _hgt_setpoint; ///< demanded height tracked by the TECS algorithm (m)
|
||||
float _hgt_setpoint_in_prev; ///< previous value of _hgt_setpoint after noise filtering (m)
|
||||
float _hgt_setpoint_prev; ///< previous value of _hgt_setpoint after noise filtering and rate limiting (m)
|
||||
float _hgt_setpoint_adj; ///< demanded height used by the control loops after all filtering has been applied (m)
|
||||
float _hgt_setpoint_adj_prev; ///< value of _hgt_setpoint_adj from previous frame (m)
|
||||
float _hgt_rate_setpoint; ///< demanded climb rate tracked by the TECS algorithm
|
||||
|
||||
// vehicle physical limits
|
||||
float _pitch_setpoint_unc; ///< pitch demand before limiting (rad)
|
||||
float _STE_rate_max; ///< specific total energy rate upper limit achieved when throttle is at _throttle_setpoint_max (m**2/sec**3)
|
||||
float _STE_rate_min; ///< specific total energy rate lower limit acheived when throttle is at _throttle_setpoint_min (m**2/sec**3)
|
||||
float _throttle_setpoint_max; ///< normalised throttle upper limit
|
||||
float _throttle_setpoint_min; ///< normalised throttle lower limit
|
||||
float _pitch_setpoint_max; ///< pitch demand upper limit (rad)
|
||||
float _pitch_setpoint_min; ///< pitch demand lower limit (rad)
|
||||
float _throttle_slewrate; ///< throttle demand slew rate limit (1/sec)
|
||||
|
||||
// specific energy quantities
|
||||
float _SPE_setpoint; ///< specific potential energy demand (m**2/sec**2)
|
||||
float _SKE_setpoint; ///< specific kinetic energy demand (m**2/sec**2)
|
||||
float _SPE_rate_setpoint; ///< specific potential energy rate demand (m**2/sec**3)
|
||||
float _SKE_rate_setpoint; ///< specific kinetic energy rate demand (m**2/sec**3)
|
||||
float _SPE_estimate; ///< specific potential energy estimate (m**2/sec**2)
|
||||
float _SKE_estimate; ///< specific kinetic energy estimate (m**2/sec**2)
|
||||
float _SPE_rate; ///< specific potential energy rate estimate (m**2/sec**3)
|
||||
float _SKE_rate; ///< specific kinetic energy rate estimate (m**2/sec**3)
|
||||
|
||||
// specific energy error quantities
|
||||
float _STE_error; ///< specific total energy error (m**2/sec**2)
|
||||
float _STE_rate_error; ///< specific total energy rate error (m**2/sec**3)
|
||||
float _SEB_error; ///< specific energy balance error (m**2/sec**2)
|
||||
float _SEB_rate_error; ///< specific energy balance rate error (m**2/sec**3)
|
||||
|
||||
// time steps (non-fixed)
|
||||
float _dt; ///< Time since last update of main TECS loop (sec)
|
||||
static constexpr float DT_MIN = 0.001f; ///< minimum allowed value of _dt (sec)
|
||||
static constexpr float DT_DEFAULT = 0.02f; ///< default value for _dt (sec)
|
||||
static constexpr float DT_MAX = 1.0f; ///< max value of _dt allowed before a filter state reset is performed (sec)
|
||||
|
||||
// controller mode logic
|
||||
bool _underspeed_detected; ///< true when an underspeed condition has been detected
|
||||
bool _detect_underspeed_enabled; ///< true when underspeed detection is enabled
|
||||
bool _uncommanded_descent_recovery; ///< true when a continuous descent caused by an unachievable airspeed demand has been detected
|
||||
bool _climbout_mode_active; ///< true when in climbout mode
|
||||
bool _airspeed_enabled; ///< true when airspeed use has been enabled
|
||||
bool _states_initalized; ///< true when TECS states have been iniitalized
|
||||
bool _in_air; ///< true when the vehicle is flying
|
||||
|
||||
/**
|
||||
* Update the airspeed internal state using a second order complementary filter
|
||||
*/
|
||||
void _update_speed_states(float airspeed_setpoint, float indicated_airspeed, float eas_to_tas);
|
||||
|
||||
/**
|
||||
* Update the desired airspeed
|
||||
*/
|
||||
void _update_speed_setpoint();
|
||||
|
||||
/**
|
||||
* Update the desired height
|
||||
*/
|
||||
void _update_height_setpoint(float desired, float state);
|
||||
|
||||
/**
|
||||
* Detect if the system is not capable of maintaining airspeed
|
||||
*/
|
||||
void _detect_underspeed(void);
|
||||
|
||||
/**
|
||||
* Update specific energy
|
||||
*/
|
||||
void _update_energy_estimates(void);
|
||||
|
||||
/**
|
||||
* Update throttle setpoint
|
||||
*/
|
||||
void _update_throttle_setpoint(float throttle_cruise, const math::Matrix<3, 3> &rotMat);
|
||||
|
||||
/**
|
||||
* Detect an uncommanded descent
|
||||
*/
|
||||
void _detect_uncommanded_descent(void);
|
||||
|
||||
/**
|
||||
* Update the pitch setpoint
|
||||
*/
|
||||
void _update_pitch_setpoint(void);
|
||||
|
||||
/**
|
||||
* Initialize the controller
|
||||
*/
|
||||
void _initialize_states(float pitch, float throttle_cruise, float baro_altitude, float min_pitch, float eas_to_tas);
|
||||
|
||||
/**
|
||||
* Calculate specific total energy rate limits
|
||||
*/
|
||||
void _update_STE_rate_lim(void);
|
||||
|
||||
};
|
||||
Loading…
Reference in New Issue