PX4-Autopilot/src/modules/land_detector/FixedwingLandDetector.cpp

130 lines
4.4 KiB
C++

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/**
* @file FixedwingLandDetector.cpp
*
* @author Johan Jansen <jnsn.johan@gmail.com>
* @author Lorenz Meier <lorenz@px4.io>
* @author Julian Oes <julian@oes.ch>
*/
#include <matrix/math.hpp>
#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);
}
void FixedwingLandDetector::_update_topics()
{
_airspeed_sub.update(&_airspeed);
_vehicle_acceleration_sub.update(&_vehicle_acceleration);
_vehicle_local_position_sub.update(&_vehicle_local_position);
}
void FixedwingLandDetector::_update_params()
{
parameter_update_s param_update;
if (_param_update_sub.update(&param_update)) {
_update_params();
}
}
float FixedwingLandDetector::_get_max_altitude()
{
// TODO
// This means no altitude limit as the limit
// is always current position plus 10000 meters
return roundf(-_vehicle_local_position.z + 10000);
}
bool FixedwingLandDetector::_get_landed_state()
{
// only trigger flight conditions if we are armed
if (!_actuator_armed.armed) {
return true;
}
bool landDetected = false;
if (hrt_elapsed_time(&_vehicle_local_position.timestamp) < 500_ms) {
// 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_filtered = 0.95f * _airspeed_filtered + 0.05f * _airspeed.true_airspeed_m_s;
// A leaking lowpass prevents biases from building up, but
// gives a mostly correct response for short impulses.
const matrix::Vector3f accel{_vehicle_acceleration.xyz};
const float acc_hor = sqrtf(accel(0) * accel(0) + accel(1) * accel(1));
_xy_accel_filtered = _xy_accel_filtered * 0.8f + acc_hor * 0.18f;
// crude land detector for fixedwing
landDetected = _xy_accel_filtered < _param_lndfw_xyaccel_max.get()
&& _airspeed_filtered < _param_lndfw_airspd.get()
&& _velocity_xy_filtered < _param_lndfw_vel_xy_max.get()
&& _velocity_z_filtered < _param_lndfw_vel_z_max.get();
} else {
// Control state topic has timed out and we need to assume we're landed.
landDetected = true;
}
return landDetected;
}
} // namespace land_detector