PX4-Autopilot/src/lib/FlightTasks/tasks/ManualAltitudeSmoothVel/FlightTaskManualAltitudeSmoothVel.cpp

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/**
 * @file FlightManualAltitude.cpp
 */

#include "FlightTaskManualAltitudeSmoothVel.hpp"

#include <float.h>

using namespace matrix;

bool FlightTaskManualAltitudeSmoothVel::activate(vehicle_local_position_setpoint_s last_setpoint)
{
	bool ret = FlightTaskManualAltitude::activate(last_setpoint);

	// Check if the previous FlightTask provided setpoints
	checkSetpoints(last_setpoint);

	_smoothing.reset(last_setpoint.acc_z, last_setpoint.vz, last_setpoint.z);

	_initEkfResetCounters();
	_resetPositionLock();

	return ret;
}

void FlightTaskManualAltitudeSmoothVel::reActivate()
{
	// The task is reacivated while the vehicle is on the ground. To detect takeoff in mc_pos_control_main properly
	// using the generated jerk, reset the z derivatives to zero
	_smoothing.reset(0.f, 0.f, _position(2));

	_initEkfResetCounters();
	_resetPositionLock();
}

void FlightTaskManualAltitudeSmoothVel::checkSetpoints(vehicle_local_position_setpoint_s &setpoints)
{
	// If the position setpoint is unknown, set to the current postion
	if (!PX4_ISFINITE(setpoints.z)) { setpoints.z = _position(2); }

	// If the velocity setpoint is unknown, set to the current velocity
	if (!PX4_ISFINITE(setpoints.vz)) { setpoints.vz = _velocity(2); }

	// No acceleration estimate available, set to zero if the setpoint is NAN
	if (!PX4_ISFINITE(setpoints.acc_z)) { setpoints.acc_z = 0.f; }
}

void FlightTaskManualAltitudeSmoothVel::_resetPositionLock()
{
	// Always start unlocked
	_position_lock_z_active = false;
	_position_setpoint_z_locked = NAN;
}

void FlightTaskManualAltitudeSmoothVel::_initEkfResetCounters()
{
	_reset_counters.z = _sub_vehicle_local_position->get().z_reset_counter;
	_reset_counters.vz = _sub_vehicle_local_position->get().vz_reset_counter;
}

void FlightTaskManualAltitudeSmoothVel::_checkEkfResetCounters()
{
	if (_sub_vehicle_local_position->get().z_reset_counter != _reset_counters.z) {
		_smoothing.setCurrentPosition(_position(2));
		_reset_counters.z = _sub_vehicle_local_position->get().z_reset_counter;
	}

	if (_sub_vehicle_local_position->get().vz_reset_counter != _reset_counters.vz) {
		_smoothing.setCurrentVelocity(_velocity(2));
		_reset_counters.vz = _sub_vehicle_local_position->get().vz_reset_counter;
	}
}

void FlightTaskManualAltitudeSmoothVel::_updateSetpoints()
{
	float pos_sp_smooth;

	_smoothing.updateTraj(_deltatime);

	_jerk_setpoint(2) = _smoothing.getCurrentJerk();
	_acceleration_setpoint(2) = _smoothing.getCurrentAcceleration();
	_vel_sp_smooth = _smoothing.getCurrentVelocity();
	pos_sp_smooth = _smoothing.getCurrentPosition();

	/* Get yaw setpont, un-smoothed position setpoints.*/
	FlightTaskManualAltitude::_updateSetpoints();

	/* Update constraints */
	if (_velocity_setpoint(2) < 0.f) { // up
		_smoothing.setMaxAccel(_param_mpc_acc_up_max.get());
		_smoothing.setMaxVel(_constraints.speed_up);

	} else { // down
		_smoothing.setMaxAccel(_param_mpc_acc_down_max.get());
		_smoothing.setMaxVel(_constraints.speed_down);
	}

	float jerk = _param_mpc_jerk_max.get();

	_checkEkfResetCounters();

	/* Check for position unlock
	 * During a position lock -> position unlock transition, we have to make sure that the velocity setpoint
	 * is continuous. We know that the output of the position loop (part of the velocity setpoint) will suddenly become null
	 * and only the feedforward (generated by this flight task) will remain. This is why the previous input of the velocity controller
	 * is used to set current velocity of the trajectory.
	 */

	const float velocity_target_z = _velocity_setpoint(2);

	if (fabsf(velocity_target_z) > FLT_EPSILON) {
		if (_position_lock_z_active) {
			_smoothing.setCurrentVelocity(_velocity_setpoint_feedback(
							      2)); // Start the trajectory at the current velocity setpoint
			_position_setpoint_z_locked = NAN;
		}

		_position_lock_z_active = false;
	}

	_smoothing.setMaxJerk(jerk);
	_smoothing.updateDurations(_velocity_setpoint(2));

	if (!_position_lock_z_active) {
		_smoothing.setCurrentPosition(_position(2));
	}

	_velocity_setpoint(2) = _vel_sp_smooth; // Feedforward

	if (fabsf(_vel_sp_smooth) < 0.1f &&
	    fabsf(_acceleration_setpoint(2)) < .2f &&
	    fabsf(velocity_target_z) <= FLT_EPSILON) {
		_position_lock_z_active = true;
	}

	// Set valid position setpoint while in position lock.
	// When the position lock condition above is false, it does not
	// mean that the unlock condition is true. This is why
	// we are checking the lock flag here.
	if (_position_lock_z_active) {
		_position_setpoint_z_locked = pos_sp_smooth;

		// If the velocity setpoint is smaller than 1mm/s and that the acceleration is 0, force the setpoints
		// to zero. This is required because the generated velocity is never exactly zero and if the drone hovers
		// for a long period of time, thr drift of the position setpoint will be noticeable.
		if (fabsf(_velocity_setpoint(2)) < 1e-3f && fabsf(_acceleration_setpoint(2)) < FLT_EPSILON) {
			_velocity_setpoint(2) = 0.f;
			_acceleration_setpoint(2) = 0.f;
			_smoothing.setCurrentVelocity(0.f);
			_smoothing.setCurrentAcceleration(0.f);
		}
	}

	_position_setpoint(2) = _position_setpoint_z_locked;
}