PX4-Autopilot/src/lib/FlightTasks/tasks/ManualPositionSmoothVel/FlightTaskManualPositionSmoothVel.cpp

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#include "FlightTaskManualPositionSmoothVel.hpp"

#include <mathlib/mathlib.h>
#include <float.h>

using namespace matrix;

bool FlightTaskManualPositionSmoothVel::activate()
{
	bool ret = FlightTaskManualPosition::activate();

	reset(Axes::XYZ);

	return ret;
}

void FlightTaskManualPositionSmoothVel::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
	reset(Axes::XYZ, true);
}

void FlightTaskManualPositionSmoothVel::reset(Axes axes, bool force_z_zero)
{
	int count;

	switch (axes) {
	case Axes::XY:
		count = 2;
		break;

	case Axes::XYZ:
		count = 3;
		break;

	default:
		count = 0;
		break;
	}

	// TODO: get current accel
	for (int i = 0; i < count; ++i) {
		_smoothing[i].reset(0.f, _velocity(i), _position(i));
	}

	// Set the z derivatives to zero
	if (force_z_zero) {
		_smoothing[2].reset(0.f, 0.f, _position(2));
	}

	_position_lock_xy_active = false;
	_position_lock_z_active = false;
	_position_setpoint_xy_locked(0) = NAN;
	_position_setpoint_xy_locked(1) = NAN;
	_position_setpoint_z_locked = NAN;
}

void FlightTaskManualPositionSmoothVel::_checkEkfResetCounters()
{
	// Check if a reset event has happened.
	if (_sub_vehicle_local_position->get().xy_reset_counter != _reset_counters.xy) {
		_smoothing[0].setCurrentPosition(_position(0));
		_smoothing[1].setCurrentPosition(_position(1));
		_reset_counters.xy = _sub_vehicle_local_position->get().xy_reset_counter;
	}

	if (_sub_vehicle_local_position->get().vxy_reset_counter != _reset_counters.vxy) {
		_smoothing[0].setCurrentVelocity(_velocity(0));
		_smoothing[1].setCurrentVelocity(_velocity(1));
		_reset_counters.vxy = _sub_vehicle_local_position->get().vxy_reset_counter;
	}

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

void FlightTaskManualPositionSmoothVel::_updateSetpoints()
{
	/* Get yaw setpont, un-smoothed position setpoints.*/
	FlightTaskManualPosition::_updateSetpoints();

	/* Update constraints */
	_smoothing[0].setMaxAccel(MPC_ACC_HOR_MAX.get());
	_smoothing[1].setMaxAccel(MPC_ACC_HOR_MAX.get());
	_smoothing[0].setMaxVel(_constraints.speed_xy);
	_smoothing[1].setMaxVel(_constraints.speed_xy);

	if (_velocity_setpoint(2) < 0.f) { // up
		_smoothing[2].setMaxAccel(MPC_ACC_UP_MAX.get());
		_smoothing[2].setMaxVel(_constraints.speed_up);

	} else { // down
		_smoothing[2].setMaxAccel(MPC_ACC_DOWN_MAX.get());
		_smoothing[2].setMaxVel(_constraints.speed_down);
	}

	float jerk[3] = {_jerk_max.get(), _jerk_max.get(), _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.
	 */
	Vector2f sticks_expo_xy = Vector2f(&_sticks_expo(0));

	if (sticks_expo_xy.length() > FLT_EPSILON) {
		if (_position_lock_xy_active) {
			_smoothing[0].setCurrentVelocity(_velocity_setpoint_feedback(
					0)); // Start the trajectory at the current velocity setpoint
			_smoothing[1].setCurrentVelocity(_velocity_setpoint_feedback(1));
			_position_setpoint_xy_locked(0) = NAN;
			_position_setpoint_xy_locked(1) = NAN;
		}

		_position_lock_xy_active = false;
	}

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

		_position_lock_z_active = false;
	}

	// During position lock, lower jerk to help the optimizer
	// to converge to 0 acceleration and velocity
	if (_position_lock_xy_active) {
		jerk[0] = 1.f;
		jerk[1] = 1.f;

	} else {
		jerk[0] = _jerk_max.get();
		jerk[1] = _jerk_max.get();
	}

	jerk[2] = _position_lock_z_active ? 1.f : _jerk_max.get();

	for (int i = 0; i < 3; ++i) {
		_smoothing[i].setMaxJerk(jerk[i]);
		_smoothing[i].updateDurations(_deltatime, _velocity_setpoint(i));
	}

	VelocitySmoothing::timeSynchronization(_smoothing, 2); // Synchronize x and y only

	if (!_position_lock_xy_active) {
		_smoothing[0].setCurrentPosition(_position(0));
		_smoothing[1].setCurrentPosition(_position(1));
	}

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

	Vector3f pos_sp_smooth;

	for (int i = 0; i < 3; ++i) {
		_smoothing[i].integrate(_acceleration_setpoint(i), _vel_sp_smooth(i), pos_sp_smooth(i));
		_velocity_setpoint(i) = _vel_sp_smooth(i); // Feedforward
		_jerk_setpoint(i) = _smoothing[i].getCurrentJerk();
	}

	// Check for position lock transition
	if (Vector2f(_vel_sp_smooth).length() < 0.1f &&
	    Vector2f(_acceleration_setpoint).length() < .2f &&
	    sticks_expo_xy.length() <= FLT_EPSILON) {
		_position_lock_xy_active = true;
	}

	if (fabsf(_vel_sp_smooth(2)) < 0.1f &&
	    fabsf(_acceleration_setpoint(2)) < .2f &&
	    fabsf(_sticks_expo(2)) <= 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_xy_active) {
		_position_setpoint_xy_locked(0) = pos_sp_smooth(0);
		_position_setpoint_xy_locked(1) = pos_sp_smooth(1);

		// 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.
		for (int i = 0; i < 2; i++) {
			if (fabsf(_velocity_setpoint(i)) < 1e-3f && fabsf(_acceleration_setpoint(0)) < FLT_EPSILON) {
				_velocity_setpoint(i) = 0.f;
				_acceleration_setpoint(i) = 0.f;
				_smoothing[i].setCurrentVelocity(0.f);
				_smoothing[i].setCurrentAcceleration(0.f);
			}
		}
	}

	if (_position_lock_z_active) {
		_position_setpoint_z_locked = pos_sp_smooth(2);

		if (fabsf(_velocity_setpoint(2)) < 1e-3f && fabsf(_acceleration_setpoint(2)) < FLT_EPSILON) {
			_velocity_setpoint(2) = 0.f;
			_acceleration_setpoint(2) = 0.f;
			_smoothing[2].setCurrentVelocity(0.f);
			_smoothing[2].setCurrentAcceleration(0.f);
		}
	}

	_position_setpoint(0) = _position_setpoint_xy_locked(0);
	_position_setpoint(1) = _position_setpoint_xy_locked(1);
	_position_setpoint(2) = _position_setpoint_z_locked;
}