px4_autopilot/apps/controllib/fixedwing.cpp

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/**
 * @file fixedwing.cpp
 *
 * Controller library code
 */

#include "fixedwing.hpp"

namespace control
{

namespace fixedwing
{

BlockYawDamper::BlockYawDamper(SuperBlock *parent, const char *name) :
	SuperBlock(parent, name),
	_rLowPass(this, "R_LP"),
	_rWashout(this, "R_HP"),
	_r2Rdr(this, "R2RDR"),
	_rudder(0)
{
}

BlockYawDamper::~BlockYawDamper() {};

void BlockYawDamper::update(float rCmd, float r)
{
	_rudder = _r2Rdr.update(rCmd -
				_rWashout.update(_rLowPass.update(r)));
}

BlockStabilization::BlockStabilization(SuperBlock *parent, const char *name) :
	SuperBlock(parent, name),
	_yawDamper(this, ""),
	_pLowPass(this, "P_LP"),
	_qLowPass(this, "Q_LP"),
	_p2Ail(this, "P2AIL"),
	_q2Elv(this, "Q2ELV"),
	_aileron(0),
	_elevator(0)
{
}

BlockStabilization::~BlockStabilization() {};

void BlockStabilization::update(float pCmd, float qCmd, float rCmd,
				float p, float q, float r)
{
	_aileron = _p2Ail.update(
			   pCmd - _pLowPass.update(p));
	_elevator = _q2Elv.update(
			    qCmd - _qLowPass.update(q));
	_yawDamper.update(rCmd, r);
}

BlockHeadingHold::BlockHeadingHold(SuperBlock *parent, const char *name) :
	SuperBlock(parent, name),
	_psi2Phi(this, "PSI2PHI"),
	_phi2P(this, "PHI2P"),
	_phiLimit(this, "PHI_LIM")
{
}

BlockHeadingHold::~BlockHeadingHold() {};

float BlockHeadingHold::update(float psiCmd, float phi, float psi, float p)
{
	float psiError = _wrap_pi(psiCmd - psi);
	float phiCmd = _phiLimit.update(_psi2Phi.update(psiError));
	return _phi2P.update(phiCmd - phi);
}

BlockVelocityHoldBackside::BlockVelocityHoldBackside(SuperBlock *parent, const char *name) :
	SuperBlock(parent, name),
	_v2Theta(this, "V2THE"),
	_theta2Q(this, "THE2Q"),
	_theLimit(this, "THE"),
	_vLimit(this, "V")
{
}

BlockVelocityHoldBackside::~BlockVelocityHoldBackside() {};

float BlockVelocityHoldBackside::update(float vCmd, float v, float theta, float q)
{
	// negative sign because nose over to increase speed
	float thetaCmd = _theLimit.update(-_v2Theta.update(_vLimit.update(vCmd) - v));
	return _theta2Q.update(thetaCmd - theta);
}

BlockVelocityHoldFrontside::BlockVelocityHoldFrontside(SuperBlock *parent, const char *name) :
	SuperBlock(parent, name),
	_v2Thr(this, "V2THR")
{
}

BlockVelocityHoldFrontside::~BlockVelocityHoldFrontside() {};

float BlockVelocityHoldFrontside::update(float vCmd, float v)
{
	return _v2Thr.update(vCmd - v);
}

BlockAltitudeHoldBackside::BlockAltitudeHoldBackside(SuperBlock *parent, const char *name) :
	SuperBlock(parent, name),
	_h2Thr(this, "H2THR"),
	_throttle(0)
{
}

BlockAltitudeHoldBackside::~BlockAltitudeHoldBackside() {};

void BlockAltitudeHoldBackside::update(float hCmd, float h)
{
	_throttle = _h2Thr.update(hCmd - h);
}

BlockAltitudeHoldFrontside::BlockAltitudeHoldFrontside(SuperBlock *parent, const char *name) :
	SuperBlock(parent, name),
	_h2Theta(this, "H2THE"),
	_theta2Q(this, "THE2Q")
{
}

BlockAltitudeHoldFrontside::~BlockAltitudeHoldFrontside() {};

float BlockAltitudeHoldFrontside::update(float hCmd, float h, float theta, float q)
{
	float thetaCmd = _h2Theta.update(hCmd - h);
	return _theta2Q.update(thetaCmd - theta);
}

BlockBacksideAutopilot::BlockBacksideAutopilot(SuperBlock *parent,
		const char *name,
		BlockStabilization *stabilization) :
	SuperBlock(parent, name),
	_stabilization(stabilization),
	_headingHold(this, ""),
	_velocityHold(this, ""),
	_altitudeHold(this, ""),
	_trimAil(this, "TRIM_AIL"),
	_trimElv(this, "TRIM_ELV"),
	_trimRdr(this, "TRIM_RDR"),
	_trimThr(this, "TRIM_THR")
{
}

BlockBacksideAutopilot::~BlockBacksideAutopilot() {};

void BlockBacksideAutopilot::update(float hCmd, float vCmd, float rCmd, float psiCmd,
				    float h, float v,
				    float phi, float theta, float psi,
				    float p, float q, float r)
{
	_altitudeHold.update(hCmd, h);
	_stabilization->update(
		_headingHold.update(psiCmd, phi, psi, p),
		_velocityHold.update(vCmd, v, theta, q),
		rCmd,
		p, q, r);
}

BlockWaypointGuidance::BlockWaypointGuidance(SuperBlock *parent, const char *name) :
	SuperBlock(parent, name),
	_xtYawLimit(this, "XT2YAW"),
	_xt2Yaw(this, "XT2YAW"),
	_psiCmd(0)
{
}

BlockWaypointGuidance::~BlockWaypointGuidance() {};

void BlockWaypointGuidance::update(vehicle_global_position_s &pos,
				   vehicle_attitude_s &att,
				   vehicle_global_position_setpoint_s &posCmd,
				   vehicle_global_position_setpoint_s &lastPosCmd)
{

	// heading to waypoint
	float psiTrack = get_bearing_to_next_waypoint(
				 (double)pos.lat / (double)1e7d,
				 (double)pos.lon / (double)1e7d,
				 (double)posCmd.lat / (double)1e7d,
				 (double)posCmd.lon / (double)1e7d);

	// cross track
	struct crosstrack_error_s xtrackError;
	get_distance_to_line(&xtrackError,
			     (double)pos.lat / (double)1e7d,
			     (double)pos.lon / (double)1e7d,
			     (double)lastPosCmd.lat / (double)1e7d,
			     (double)lastPosCmd.lon / (double)1e7d,
			     (double)posCmd.lat / (double)1e7d,
			     (double)posCmd.lon / (double)1e7d);

	_psiCmd = _wrap_2pi(psiTrack -
			    _xtYawLimit.update(_xt2Yaw.update(xtrackError.distance)));
}

BlockUorbEnabledAutopilot::BlockUorbEnabledAutopilot(SuperBlock *parent, const char *name) :
	SuperBlock(parent, name),
	// subscriptions
	_att(&getSubscriptions(), ORB_ID(vehicle_attitude), 20),
	_attCmd(&getSubscriptions(), ORB_ID(vehicle_attitude_setpoint), 20),
	_ratesCmd(&getSubscriptions(), ORB_ID(vehicle_rates_setpoint), 20),
	_pos(&getSubscriptions() , ORB_ID(vehicle_global_position), 20),
	_posCmd(&getSubscriptions(), ORB_ID(vehicle_global_position_setpoint), 20),
	_manual(&getSubscriptions(), ORB_ID(manual_control_setpoint), 20),
	_status(&getSubscriptions(), ORB_ID(vehicle_status), 20),
	_param_update(&getSubscriptions(), ORB_ID(parameter_update), 1000), // limit to 1 Hz
	// publications
	_actuators(&getPublications(), ORB_ID(actuator_controls_0))
{
}

BlockUorbEnabledAutopilot::~BlockUorbEnabledAutopilot() {};

BlockMultiModeBacksideAutopilot::BlockMultiModeBacksideAutopilot(SuperBlock *parent, const char *name) :
	BlockUorbEnabledAutopilot(parent, name),
	_stabilization(this, ""), // no name needed, already unique
	_backsideAutopilot(this, "", &_stabilization),
	_guide(this, ""),
	_vCmd(this, "V_CMD"),
	_attPoll(),
	_lastPosCmd(),
	_timeStamp(0)
{
	_attPoll.fd = _att.getHandle();
	_attPoll.events = POLLIN;
}

void BlockMultiModeBacksideAutopilot::update()
{
	// wait for a sensor update, check for exit condition every 100 ms
	if (poll(&_attPoll, 1, 100) < 0) return; // poll error

	uint64_t newTimeStamp = hrt_absolute_time();
	float dt = (newTimeStamp - _timeStamp) / 1.0e6f;
	_timeStamp = newTimeStamp;

	// check for sane values of dt
	// to prevent large control responses
	if (dt > 1.0f || dt < 0) return;

	// set dt for all child blocks
	setDt(dt);

	// store old position command before update if new command sent
	if (_posCmd.updated()) {
		_lastPosCmd = _posCmd.getData();
	}

	// check for new updates
	if (_param_update.updated()) updateParams();

	// get new information from subscriptions
	updateSubscriptions();

	// default all output to zero unless handled by mode
	for (unsigned i = 4; i < NUM_ACTUATOR_CONTROLS; i++)
		_actuators.control[i] = 0.0f;

	// only update guidance in auto mode
	if (_status.state_machine == SYSTEM_STATE_AUTO) {
		// update guidance
		_guide.update(_pos, _att, _posCmd, _lastPosCmd);
	}

	// XXX handle STABILIZED (loiter on spot) as well
	// once the system switches from manual or auto to stabilized
	// the setpoint should update to loitering around this position

	// handle autopilot modes
	if (_status.state_machine == SYSTEM_STATE_AUTO ||
		_status.state_machine == SYSTEM_STATE_STABILIZED) {

		// update guidance
		_guide.update(_pos, _att, _posCmd, _lastPosCmd);

		// calculate velocity, XXX should be airspeed, but using ground speed for now
		float v = sqrtf(_pos.vx * _pos.vx + _pos.vy * _pos.vy + _pos.vz * _pos.vz);

		// commands
		float rCmd = 0;

		_backsideAutopilot.update(
			_posCmd.altitude, _vCmd.get(), rCmd, _guide.getPsiCmd(),
			_pos.alt, v,
			_att.roll, _att.pitch, _att.yaw,
			_att.rollspeed, _att.pitchspeed, _att.yawspeed
		);
		_actuators.control[CH_AIL] = _backsideAutopilot.getAileron();
		_actuators.control[CH_ELV] = - _backsideAutopilot.getElevator();
		_actuators.control[CH_RDR] = _backsideAutopilot.getRudder();
		_actuators.control[CH_THR] = _backsideAutopilot.getThrottle();

		// XXX limit throttle to manual setting (safety) for now.
		// If it turns out to be confusing, it can be removed later once
		// a first binary release can be targeted.
		// This is not a hack, but a design choice.

		/* do not limit in HIL */
		if (!_status.flag_hil_enabled) {
			/* limit to value of manual throttle */
			_actuators.control[CH_THR] = (_actuators.control[CH_THR] < _manual.throttle) ?
							_actuators.control[CH_THR] : _manual.throttle;
		}


	} else if (_status.state_machine == SYSTEM_STATE_MANUAL) {

		if (_status.manual_control_mode == VEHICLE_MANUAL_CONTROL_MODE_DIRECT) {

			_actuators.control[CH_AIL] = _manual.roll;
			_actuators.control[CH_ELV] = _manual.pitch;
			_actuators.control[CH_RDR] = _manual.yaw;
			_actuators.control[CH_THR] = _manual.throttle;

		} else if (_status.manual_control_mode == VEHICLE_MANUAL_CONTROL_MODE_SAS) {

			_stabilization.update(_manual.roll, _manual.pitch, _manual.yaw,
			_att.rollspeed, _att.pitchspeed, _att.yawspeed);

			_actuators.control[CH_AIL] = _stabilization.getAileron();
			_actuators.control[CH_ELV] = - _stabilization.getElevator();
			_actuators.control[CH_RDR] = _stabilization.getRudder();
			_actuators.control[CH_THR] = _manual.throttle;
		}
	}

	// update all publications
	updatePublications();
}

BlockMultiModeBacksideAutopilot::~BlockMultiModeBacksideAutopilot()
{
	// send one last publication when destroyed, setting
	// all output to zero
	for (unsigned i = 0; i < NUM_ACTUATOR_CONTROLS; i++)
		_actuators.control[i] = 0.0f;

	updatePublications();
}

} // namespace fixedwing

} // namespace control