Provides a simple, kinematics-based model for surface vessels. More...

Inheritance diagram for DtSurfaceEntityActuator:

Public Member Functions
	DtSurfaceEntityActuator (const DtString &name, DtVrfObject owner, DtSimManager simManager, DtComponentDescriptor desc=0, DtReaderWriterRegistry parentRegistry=0)
	(const DtString&,DtVrfObject,DtSimManager,
virtual	~DtSurfaceEntityActuator ()
	Destructor.
virtual bool	init ()
	Calls down to the base class, null checks entity(), calls createPSR(), and then caches the entity's state repository in mySurfaceEntityState.
virtual DtString	type () const
	Returns a string identifies the class type of component.
virtual bool	postAddComponentsInit ()
	to initalize the PSR after the components have been created and initialized initP
virtual void	initProcessSR ()
	the maxYawRate, maxYawAcceleration, and stoppingSpeed in myProcessState from the DtSurfaceEntityActuatorDescriptor
virtual void	tick ()
	Calculates new kinematic state.
virtual double	calculateRudderYawAcceleration ()
	Calculates the signed yaw acceleration due to rudder.
virtual double	calculateResistanceYawAcceleration ()
	Calculates the signed yaw acceleration due to resistance.
virtual const DtVector	calculateThrottleAcceleration ()
	Calculates the acceleration due to thrust, expressed in body coordinates.
virtual const DtVector	calculateDragAcceleration ()
	Calculates the drag acceleration, expressed in body coordinates.
virtual bool	clampSmallVelocityToZero ()
	Called by tick() to zero out the velocity and acceleration of ships which are close to stopping due to drag.
virtual double	stoppingSpeed ()
	Returns the speed used by clampSmallVelocityToZero() to determine when to stop drifting ships.
virtual void	useFuel (double fuelUsed)
	Looks up the value of the resource named 'fuel' in the entity's resource manager and deducts the given amount.
virtual double	fuelLeft () const
	Looks up the value of the resource named 'fuel' in the entity's resource manager.
Static Public Member Functions
static DtSimComponent *	creator (const DtString &name, DtVrfObject owner, DtSimManager simManager, DtComponentDescriptor desc=0, DtReaderWriterRegistry parentRegistry=0)
	(const DtString&,DtVrfObject,DtSimManager,
Protected Member Functions
virtual bool	createPortGroups ()
	Creates the mySurfaceControlPortGroup input port group and adds it to the component.
virtual bool	createPorts ()
	Creates myThrottlePort and myRudderPort and adds them to mySurfaceControlPortGroup.
virtual void	integratePosition (double dT)
	Assumes that myRelativeAcceleration holds the freshly calculated total acceleration for this frame, expressed in local coordinates.
virtual void	integrateOrientation (double dT)
	Assumes that myBodyRotationalAcceleration holds the freshly calculated total rotational acceleration for this frame, expressed in body coordinates.
void	constrainYawAcceleration (double &yawAcceleration, double yawRate, double maxYawRate, double dT)
	Constrain incoming yaw acceleration such that resulting yawRate for the given time interval does not exceed the given maximum yaw rate for the time interval dT.
virtual void	updateRepository ()
	Copy newly calculated state data from myLocalPosition, myRelativeVelocity, myRelativeAcceleration, myOrientation and myBodyRotationRates into the object's state repository.
DtSurfaceEntityStateRepository *	surfaceEntityState (void) const
virtual bool	createPSR ()
	Creates myProcessState data member, and adds it to our process state repository manager.
	DtSurfaceEntityActuator ()
	default constructor; not implemented
	DtSurfaceEntityActuator (const DtSurfaceEntityActuator &orig)
	copy constructor; not implemented
const DtSurfaceEntityActuator &	operator= (const DtSurfaceEntityActuator &orig)
	assignment operator; not implemented
Protected Attributes
DtSurfaceEntityStateRepository *	mySurfaceEntityState
DtSurfaceEntityActuatorDescriptor *	mySurfaceEntityActuatorDescriptor
DtDcm	myBodyToLocalMatrix
DtDcm	myLocalToBodyMatrix
DtVector	myLocalPosition
DtVector	myRelativeVelocity
DtVector	myRelativeAcceleration
DtTaitBryan	myOrientation
DtVector	myBodyRotationRates
DtVector	myBodyRotationalAcceleration
DtSurfaceMovementPSR *	myProcessState
	Container for state data associated with this component.
bool	myOutOfFuelWarningPrinted
Ports and Port Groups
DtInputPortGroup *	mySurfaceControlPortGroup
	Input Port Group Name: surface-control Input Port Group Description:
DtConstrainedAnalogInputPort *	myThrottlePort
	Input Port Name: throttle Input Port Description: Input Port Range: 0.0 to 1.0 Input Port Default Value: Input Group Parent: surface-control.
DtConstrainedAnalogInputPort *	myRudderPort
	Input Port Name: rudder Input Port Description: Input Port Range: -1.0 to 1.0 Input Port Default Value: Input Group Parent: surface-control.
DtBooleanOutputPort *	mySmallVelocityClampedPort
	Output Port Name: clamp-small-vel-zero Output Port Description: Output Port Default Value: True .

Detailed Description

Provides a simple, kinematics-based model for surface vessels.

End User Description: The DtSurfaceEntityActuator converts throttle and rudder inputs into orientation, acceleration, velocity, and position.

The throttle control values are used to determine acceleration based on linear proportions of the specified maximum acceleration and velocity. The valid range of throttle control values are from 1.0 (maximum forward thrust) to -1.0 (maximum reverse thrust).
The rudder control values are used to determine the rotational acceleration based on linear proportions of the specified maximum rotational rate and acceleration as well asthe acceleration and velocity listed above. The valid range of rudder control values are from 1.0 (full right rudder) to -1.0 (full left rudder).
Resistance accelerations are calculated to insure that a ship will not accelerate beyond it's maximum speed or turning rate.

Uses Descriptor Type: DtSurfaceEntityActuatorDescriptor

Constructor & Destructor Documentation

DtSurfaceEntityActuator::DtSurfaceEntityActuator	(	const DtString &	name,
		DtVrfObject *	owner,
		DtSimManager *	simManager,
		DtComponentDescriptor *	desc = `0`,
		DtReaderWriterRegistry *	parentRegistry = `0`
	)

(const DtString&,DtVrfObject*,DtSimManager*,

Parameters:

name	Reader writer name of this component.
owner	The DtVrfObject that owns this component
simManager	The simulation manager (provides access to terrain, message interface, simulation clock).
desc	The component descriptor used to initialize this component.
parentRegistry	Pointer to the parent reader writer registry (the containing object that reads/writes this object).

(const DtString&,DtVrfObject*,DtSimManager*, DtComponentDescriptor*,DtReaderWriterRegistry* parentRegistry) Constructor

virtual DtSurfaceEntityActuator::~DtSurfaceEntityActuator ( ) [virtual]

Destructor.

Removes myProcessState from the process state repository manager. Deletes all ports and port groups.

DtSurfaceEntityActuator::DtSurfaceEntityActuator ( ) [protected]

default constructor; not implemented

DtSurfaceEntityActuator::DtSurfaceEntityActuator ( const DtSurfaceEntityActuator & orig ) [protected]

copy constructor; not implemented

Member Function Documentation

virtual bool DtSurfaceEntityActuator::init ( ) [virtual]

Calls down to the base class, null checks entity(), calls createPSR(), and then caches the entity's state repository in mySurfaceEntityState.

Reimplemented from DtActuatorComponent.

virtual DtString DtSurfaceEntityActuator::type ( ) const [virtual]

Returns a string identifies the class type of component.

Type values are defined in compTypes.h. DtSimComponent creation functions are registered with the DtSimComponentFactory using the type values as the key.

Returns:: DtSurfaceEntityActuatorType

Reimplemented from DtSimComponent.

virtual bool DtSurfaceEntityActuator::postAddComponentsInit ( ) [virtual]

to initalize the PSR after the components have been created and initialized initP

Reimplemented from DtSimComponent.

virtual void DtSurfaceEntityActuator::initProcessSR ( ) [virtual]

the maxYawRate, maxYawAcceleration, and stoppingSpeed in myProcessState from the DtSurfaceEntityActuatorDescriptor

virtual void DtSurfaceEntityActuator::tick ( ) [virtual]

Calculates new kinematic state.

The tick method carries out the following steps:

The tick() function checks whether dT (the time elapsed since the last tick call) is 0.0. If it is, tick() returns.
If isControlled() is false, and the ship is at a dead stop, the tick returns. This optimization prevents the overhead of a full tick for ships which are inactive (i.e. drifted to a stop).
The soil type at the current location is checked. If it is not not a water surface, all movement is zeroed out, updateRepository() is called and the tick returns. If there isn't a terrain intersection at the current location (water or otherwise), the ship is allowed to sail on at altitude 0.
The yaw acceleration is calculated as the sum of calculateRudderYawAcceleration() and calculateResistanceYawAcceleration() and stored in myBodyRotationalAcceleration[2]. Then a call to integrateOrientation() calculates the new orientation of the ship.
The acceleration in body coordinates is calculated as the vector sum of calculateThrottleAcceleration() and calculateDragAcceleration(). The vector product of the body acceleration and myRelativeAcceleration is stored in myBodyToLocalMatrix. Finally, the new position is calculated by a call to integratePosition().
To stop slowly drifting ships, clampSmallVelocityToZero() is called.
In order to store the values that have been calculated during the tick in the entity's state repository, updateRepository() is called.
The actuator calls dataReceived(). This is done as a convenience for future subclasses -- this actuator does not examine the newData flag.

Reimplemented from DtSimComponent.

virtual double DtSurfaceEntityActuator::calculateRudderYawAcceleration ( ) [virtual]

Calculates the signed yaw acceleration due to rudder.

The rudder yaw acceleration is calculated as a product of the current value on the rudder port, the maximum yaw acceleration specified in the descriptor, and the ratio of the current speed to the maximum speed of the vessel (from the state repository).

virtual double DtSurfaceEntityActuator::calculateResistanceYawAcceleration ( ) [virtual]

Calculates the signed yaw acceleration due to resistance.

The resistance yaw acceleration is calculated as a product of the maximum yaw acceleration (from the descriptor) and the ratio of the current yaw rate to the maximum yaw rate (squared).

virtual const DtVector DtSurfaceEntityActuator::calculateThrottleAcceleration ( ) [virtual]

Calculates the acceleration due to thrust, expressed in body coordinates.

The thrust vector is assumed to always be through the body's x-axis, so the y and z values should always be zero. The acceleration is set to zero under any of the following conditions - the entity's appearance is damaged or immobilized, the throttlePort does not have an active connection, or fuelLeft() is less than or equal to zero.

virtual const DtVector DtSurfaceEntityActuator::calculateDragAcceleration ( ) [virtual]

Calculates the drag acceleration, expressed in body coordinates.

The drag vector is always expressed in the opposite direction of the current heading. It is calculated as the ratio of the current speed to the maximum speed (squared) times the maximum acceleration.

virtual bool DtSurfaceEntityActuator::clampSmallVelocityToZero ( ) [virtual]

Called by tick() to zero out the velocity and acceleration of ships which are close to stopping due to drag.

This cuts off the asymptotic decline in velocity to make sure that the entity will eventually come to a full stop. The cutoff is determined by the value returned from stoppingSpeed.

virtual double DtSurfaceEntityActuator::stoppingSpeed ( ) [virtual]

Returns the speed used by clampSmallVelocityToZero() to determine when to stop drifting ships.

The default value is 1.0.

virtual void DtSurfaceEntityActuator::useFuel ( double fuelUsed ) [virtual]

Looks up the value of the resource named 'fuel' in the entity's resource manager and deducts the given amount.

If the resource is not found, useFuel() just returns. If the resource is found, the amount of fuel passed as the argument to useFuel() is deducted from the resource. When the resource reaches 0, a warning is printed to the object console.

virtual double DtSurfaceEntityActuator::fuelLeft ( ) const [virtual]

Looks up the value of the resource named 'fuel' in the entity's resource manager.

If the resource is not found, it returns an appropriately large constant to implement unlimited fuel. Otherwise, the value of the resource is returned.

static DtSimComponent* DtSurfaceEntityActuator::creator	(	const DtString &	name,
		DtVrfObject *	owner,
		DtSimManager *	simManager,
		DtComponentDescriptor *	desc = `0`,
		DtReaderWriterRegistry *	parentRegistry = `0`
	)		`[static]`

(const DtString&,DtVrfObject*,DtSimManager*,

Parameters:

name	Reader writer name of this component.
owner	The DtVrfObject that owns this component
simManager	The simulation manager (provides access to terrain, message interface, simulation clock).
desc	The component descriptor used to initialize this component.
parentRegistry	Pointer to the parent reader writer registry (the containing object that reads/writes this object).

(const DtString&,DtVrfObject*,DtSimManager*, DtComponentDescriptor*,DtReaderWriterRegistry* parentRegistry)

Returns:: New instance of this class.

virtual bool DtSurfaceEntityActuator::createPortGroups ( ) [protected, virtual]

Creates the mySurfaceControlPortGroup input port group and adds it to the component.

Reimplemented from DtSimComponent.

virtual bool DtSurfaceEntityActuator::createPorts ( ) [protected, virtual]

Creates myThrottlePort and myRudderPort and adds them to mySurfaceControlPortGroup.

Reimplemented from DtSimComponent.

virtual void DtSurfaceEntityActuator::integratePosition ( double dT ) [protected, virtual]

Assumes that myRelativeAcceleration holds the freshly calculated total acceleration for this frame, expressed in local coordinates.

This function integrates over dT, and stores a new velocity and position in myRelativeVelocity and myLocalPosition respectively

virtual void DtSurfaceEntityActuator::integrateOrientation ( double dT ) [protected, virtual]

Assumes that myBodyRotationalAcceleration holds the freshly calculated total rotational acceleration for this frame, expressed in body coordinates.

This function integrates over dT, and stores a new body rates, and orientation in myBodyRotationRates, and myOrientation respectively. To insure that the yaw rate does not exceed the maximum rate, constrainYawAcceleration is called.

void DtSurfaceEntityActuator::constrainYawAcceleration	(	double &	yawAcceleration,
		double	yawRate,
		double	maxYawRate,
		double	dT
	)		`[protected]`

Constrain incoming yaw acceleration such that resulting yawRate for the given time interval does not exceed the given maximum yaw rate for the time interval dT.

virtual void DtSurfaceEntityActuator::updateRepository ( ) [protected, virtual]

Copy newly calculated state data from myLocalPosition, myRelativeVelocity, myRelativeAcceleration, myOrientation and myBodyRotationRates into the object's state repository.

DtSurfaceEntityStateRepository* DtSurfaceEntityActuator::surfaceEntityState ( void ) const [protected]

virtual bool DtSurfaceEntityActuator::createPSR ( ) [protected, virtual]

Creates myProcessState data member, and adds it to our process state repository manager.

Passes in the name and type specified in the component descriptor (if they exist) to the DtVrfProcessStateRepository::createRepository factory method. If name and/or type is not specified, uses the appropriate default strings defined in procSRTypes.h.

const DtSurfaceEntityActuator& DtSurfaceEntityActuator::operator= ( const DtSurfaceEntityActuator & orig ) [protected]

assignment operator; not implemented