FixedwingLandDetector.cpp
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/****************************************************************************
*
* Copyright (c) 2013-2016 PX4 Development Team. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name PX4 nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/**
* @file FixedwingLandDetector.cpp
*
* @author Johan Jansen <jnsn.johan@gmail.com>
* @author Lorenz Meier <lorenz@px4.io>
* @author Julian Oes <julian@oes.ch>
*/
#include "FixedwingLandDetector.h"
namespace land_detector
{
FixedwingLandDetector::FixedwingLandDetector()
{
// Use Trigger time when transitioning from in-air (false) to landed (true) / ground contact (true).
_landed_hysteresis.set_hysteresis_time_from(false, LANDED_TRIGGER_TIME_US);
_landed_hysteresis.set_hysteresis_time_from(true, FLYING_TRIGGER_TIME_US);
}
bool FixedwingLandDetector::_get_landed_state()
{
// Only trigger flight conditions if we are armed.
if (!_armed) {
return true;
}
bool landDetected = false;
if (hrt_elapsed_time(&_vehicle_local_position.timestamp) < 1_s) {
// Horizontal velocity complimentary filter.
float val = 0.97f * _velocity_xy_filtered + 0.03f * sqrtf(_vehicle_local_position.vx * _vehicle_local_position.vx +
_vehicle_local_position.vy * _vehicle_local_position.vy);
if (PX4_ISFINITE(val)) {
_velocity_xy_filtered = val;
}
// Vertical velocity complimentary filter.
val = 0.99f * _velocity_z_filtered + 0.01f * fabsf(_vehicle_local_position.vz);
if (PX4_ISFINITE(val)) {
_velocity_z_filtered = val;
}
airspeed_validated_s airspeed_validated{};
_airspeed_validated_sub.copy(&airspeed_validated);
// set _airspeed_filtered to 0 if airspeed data is invalid
if (!PX4_ISFINITE(airspeed_validated.true_airspeed_m_s) || hrt_elapsed_time(&airspeed_validated.timestamp) > 1_s) {
_airspeed_filtered = 0.0f;
} else {
_airspeed_filtered = 0.95f * _airspeed_filtered + 0.05f * airspeed_validated.true_airspeed_m_s;
}
// A leaking lowpass prevents biases from building up, but
// gives a mostly correct response for short impulses.
const float acc_hor = matrix::Vector2f(_acceleration).norm();
_xy_accel_filtered = _xy_accel_filtered * 0.8f + acc_hor * 0.18f;
// Crude land detector for fixedwing.
landDetected = _airspeed_filtered < _param_lndfw_airspd.get()
&& _velocity_xy_filtered < _param_lndfw_vel_xy_max.get()
&& _velocity_z_filtered < _param_lndfw_vel_z_max.get()
&& _xy_accel_filtered < _param_lndfw_xyaccel_max.get();
} else {
// Control state topic has timed out and we need to assume we're landed.
landDetected = true;
}
return landDetected;
}
} // namespace land_detector