DtGroundCollisionAvoidanceController Class Reference

DtGroundCollisionAvoidanceController is a controller that helps entities to avoid running into other entities and/or feature obstructions. More...

Inheritance diagram for DtGroundCollisionAvoidanceController:

List of all members.

Public Member Functions
	DtGroundCollisionAvoidanceController (const DtString &name, DtVrfObject *owner, DtSimManager *simManager, DtComponentDescriptor *desc=0, DtReaderWriterRegistry *parentRegistry=0)
	(const DtString&,DtVrfObject*,DtSimManager*,
virtual	~DtGroundCollisionAvoidanceController ()
	Destructor.
virtual bool	init ()
	Initializes the follow controller name, the object ID, and the collisionBV (bounding volume)
virtual void	tick ()
	Calculate new control values based on potential collisions.
virtual double	distanceSquaredToDestination (DtVector offsetVector)
	Calculates the distance squared from the current location (in local coords) to the destination, minus the specified offset vector.
virtual void	avoidCollision (const DtCollision &potentialCollision)
	Activates all automotive ports/groups and provides the necessary steering, brake, and throttle values.
virtual void	clearCollision ()
	This just cleans up some state variables when it's determined that an entity is no longer potentially colliding.
virtual void	clearingCollision ()
	Moves the vehicle in a straight line for the defined clearingDistance after it is no longer at risk of colliding with the obstruction.
virtual DtString	type () const
	Returns a string identifies the class type of component.
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
	DtGroundCollisionAvoidanceController ()
	Default constructor; should not be called.
	DtGroundCollisionAvoidanceController (const DtGroundCollisionAvoidanceController &orig)
	copy constructor
const DtGroundCollisionAvoidanceController &	operator= (const DtGroundCollisionAvoidanceController &orig)
	assignment operator
bool	isAppreciablyMoving (DtVector velocity, double velocityTolerance) const
	If the magnitude of any component of the velocity is greater than the velocity tolerance, then the entity is considered appreciably moving.
bool	setDefaultPortValuesForAvoidance (DtAutoTransmissionGear currentGear)
	Sets the ports to appropriate default values.
bool	determineObstructionMovementDirection (DtDcm obstructionLocalOrientationMatrix, const DtVector &obstructionVelocity, int &obstructionDirectionSign) const
	Determines if the obstruction is moving forward or in reverse.
bool	followingObstruction (const DtEntityIdentifier &entityID) const
	Checks to see if the entity is currently tasked to follow the specified entity.
void	avoidMovingObstruction (const DtCollision &potentialCollision)
	Calculates and sets control values for avoiding a moving obstruction based on obstruction's relative movement (head-on, in front of, etc.) If the obstruction is moving in roughly the same direction, and the entity is in front, it does nothing.
void	avoidNonMovingObstruction (const DtCollision &potentialCollision)
	Calculates control values for avoiding a non-moving obstruction.
void	startClearingCollision (double clearingDistance)
	Sets state as appropriate for clearing a collision and then starts clearing the collision.
bool	calculateCollisionBV ()
	Calculates a bounding volume representing the potential collision volume occupied by the entity.
bool	createPortGroups ()
	Overridden to create myAutomotiveControlPortGroup.
bool	createPorts ()
	Overridden to create the automotive ports.
Protected Attributes
double	myClearingDistance
	This is only used when clearing.
bool	myAvoidingCollision
Dt3dBoundingVolume *	myCollisionBV
DtEntityIdentifier	myObjectId
bool	myHavePortGroup
DtString	myFollowEntityName
Ports and Port Groups
DtCollisionInputPort *	myCollisionAvoidancePort
	Input Port Name: potential-collision-info Input Port Description: Input Port Range: Input Port Default Value: Input Group Parent: collision-avoidance-control.
DtInputPortGroup *	myCollisionAvoidancePortGroup
	Input Port Group Name: collision-avoidance-control Input Port Group Description:
DtStringInputPort *	myFollowEntityInputPort
	Input Port Name: follow-entity-name Input Port Description: Check this port to see if any possible collision is with the entity we're suppose to follow Input Port Range: Input Port Default Value: .
DtBooleanOutputPort *	myCollisionPort
	Output Port Name: collision Output Port Description: Specifies if there's a collision occuring Output Port Range: Output Group Parent: .

---

Detailed Description

DtGroundCollisionAvoidanceController is a controller that helps entities to avoid running into other entities and/or feature obstructions.

Uses Descriptor Type: DtGroundCollisionAvoidanceDescriptor

---

Constructor & Destructor Documentation

DtGroundCollisionAvoidanceController::DtGroundCollisionAvoidanceController	(	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)

virtual DtGroundCollisionAvoidanceController::~DtGroundCollisionAvoidanceController

(

)

[virtual]

Destructor.

Cleans up any allocated ports/port groups, and bounding volumes.

DtGroundCollisionAvoidanceController::DtGroundCollisionAvoidanceController

(

)

[protected]

Default constructor; should not be called.

Here because the compiler will generate an unprotected one otherwise.

DtGroundCollisionAvoidanceController::DtGroundCollisionAvoidanceController

(

const DtGroundCollisionAvoidanceController &

orig

)

[protected]

copy constructor

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Member Function Documentation

virtual bool DtGroundCollisionAvoidanceController::init

(

)

[virtual]

Initializes the follow controller name, the object ID, and the collisionBV (bounding volume)

Returns:

A boolean indicating success or failure.

Reimplemented from DtGroundAutoControllerComponent.

virtual void DtGroundCollisionAvoidanceController::tick

(

)

[virtual]

Calculate new control values based on potential collisions.

If the controller has received potential collision data, then it acts to avoid a collision. If it does not receive collision data, but has on the previous tick, then the controller starts clearing the collision.

See also:

avoidCollision()

clearingCollision()

Reimplemented from DtSimComponent.

virtual double DtGroundCollisionAvoidanceController::distanceSquaredToDestination

(

DtVector

offsetVector

)

[virtual]

Calculates the distance squared from the current location (in local coords) to the destination, minus the specified offset vector.

Returns:

a double set to the distance squared.

virtual void DtGroundCollisionAvoidanceController::avoidCollision

(

const DtCollision &

potentialCollision

)

[virtual]

Activates all automotive ports/groups and provides the necessary steering, brake, and throttle values.

Parameters:

obstruction

A pointer to a DtVrfObject to avoid. Assumed to be non-NULL.

See also:

avoidMovingObstruction()

avoidNonMovingObstruction()

virtual void DtGroundCollisionAvoidanceController::clearCollision

(

)

[virtual]

This just cleans up some state variables when it's determined that an entity is no longer potentially colliding.

virtual void DtGroundCollisionAvoidanceController::clearingCollision

(

)

[virtual]

Moves the vehicle in a straight line for the defined clearingDistance after it is no longer at risk of colliding with the obstruction.

This is done to keep the vehicle from turning back to the goal too soon, which would cause a jitter as the vehicle went in and out of the collision state.

virtual DtString DtGroundCollisionAvoidanceController::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:

DtGroundAutoCollisionAvoidanceType

Reimplemented from DtGroundAutoControllerComponent.

static DtSimComponent* DtGroundCollisionAvoidanceController::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.

const DtGroundCollisionAvoidanceController& DtGroundCollisionAvoidanceController::operator=

(

const DtGroundCollisionAvoidanceController &

orig

)

[protected]

assignment operator

bool DtGroundCollisionAvoidanceController::isAppreciablyMoving	(	DtVector	velocity,
		double	velocityTolerance
	)		const [protected]

If the magnitude of any component of the velocity is greater than the velocity tolerance, then the entity is considered appreciably moving.

Returns:

A boolean signifying whether or not the entity is appreciably moving.

bool DtGroundCollisionAvoidanceController::setDefaultPortValuesForAvoidance

(

DtAutoTransmissionGear

currentGear

)

[protected]

Sets the ports to appropriate default values.

• Throttle is set to the approximate throttle for the ordered speed.
• Break is set to either 0 or .5 depending on dif. between current and ordered speed
• Gear is set to the specified currentGear
• Steering is set to 0.
• ParkingBrake is set to false

  Parameters:

  currentGear

  The current gear of the entity.

  Returns:

  A boolean signifying sucess or failure.

bool DtGroundCollisionAvoidanceController::determineObstructionMovementDirection	(	DtDcm	obstructionLocalOrientationMatrix,
		const DtVector &	obstructionVelocity,
		int &	obstructionDirectionSign
	)		const [protected]

Determines if the obstruction is moving forward or in reverse.

Parameters:

obstructionDirectionSign

A reference to an integer representing the direction of movement: 1 for forward, -1 for reverse.

Returns:

a boolean signifying success or failure in the calculation.

bool DtGroundCollisionAvoidanceController::followingObstruction

(

const DtEntityIdentifier &

entityID

)

const [protected]

Checks to see if the entity is currently tasked to follow the specified entity.

Returns:

A boolean signifying success or failure.

void DtGroundCollisionAvoidanceController::avoidMovingObstruction

(

const DtCollision &

potentialCollision

)

[protected]

Calculates and sets control values for avoiding a moving obstruction based on obstruction's relative movement (head-on, in front of, etc.) If the obstruction is moving in roughly the same direction, and the entity is in front, it does nothing.

If it is behind, and following the entity, then it lets the follow entity controller take over. If not following the entity, then it slows down to avoid a collision.

If the obstruction is coming head on, then the entity attempts to turn out of the way as if the obstruction was a non-moving entity.

Note:

Assumes that the obstruction is an entity, since it is moving. If the potential collision is not an entity, this function will have to be updated.

void DtGroundCollisionAvoidanceController::avoidNonMovingObstruction

(

const DtCollision &

potentialCollision

)

[protected]

Calculates control values for avoiding a non-moving obstruction.

If the entity is not following the obstruction, and the entity can turn, it turns to the opposite direction of the obstruction's location to the entity. (i.e. if the obstruction is on the right, the entity turns to the left.) Otherwise, the entity stops, since either the leader has stopped or it is unable to turn.

Note:

Does not assume that the obstruction is an entity, since it is not moving. Uses only the data contained in the collision object, and does not look up any other data (such as a vrfObject).

void DtGroundCollisionAvoidanceController::startClearingCollision

(

double

clearingDistance

)

[protected]

Sets state as appropriate for clearing a collision and then starts clearing the collision.

Parameters:

clearingDistance

The distance the entity will move before it considers itself of having fully avoided the collision. This is to prevent entities from immediately turning back into the path of the potential collision once initially avoided it.

See also:

clearingCollision()

bool DtGroundCollisionAvoidanceController::calculateCollisionBV

(

)

[protected]

Calculates a bounding volume representing the potential collision volume occupied by the entity.

The entities oriented bounding volume is extended in the direction of travel. It represents a prediction of the entity's future movement for some period of time.

Returns:

A boolean signifying success or failure. If the function fails, the bounding volume is not defined to be valid.

Note:

Almost exact same function as in the DtObstructionSensor class.

This function assumes simplified movement, and only works for movement "forward/backward" in body coordinates (x direction). For more complicated collision bounding volumes, this function must be overridden.

bool DtGroundCollisionAvoidanceController::createPortGroups

(

)

[protected, virtual]

Overridden to create myAutomotiveControlPortGroup.

Reimplemented from DtGroundAutoControllerComponent.

bool DtGroundCollisionAvoidanceController::createPorts

(

)

[protected, virtual]

Overridden to create the automotive ports.

Reimplemented from DtGroundAutoControllerComponent.

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Member Data Documentation

double DtGroundCollisionAvoidanceController::myClearingDistance [protected]

This is only used when clearing.

bool DtGroundCollisionAvoidanceController::myAvoidingCollision [protected]

Dt3dBoundingVolume* DtGroundCollisionAvoidanceController::myCollisionBV [protected]

DtEntityIdentifier DtGroundCollisionAvoidanceController::myObjectId [protected]

bool DtGroundCollisionAvoidanceController::myHavePortGroup [protected]

DtString DtGroundCollisionAvoidanceController::myFollowEntityName [protected]

DtCollisionInputPort* DtGroundCollisionAvoidanceController::myCollisionAvoidancePort [protected]

Input Port Name: potential-collision-info
Input Port Description:
Input Port Range:
Input Port Default Value:
Input Group Parent: collision-avoidance-control.

DtInputPortGroup* DtGroundCollisionAvoidanceController::myCollisionAvoidancePortGroup [protected]

Input Port Group Name: collision-avoidance-control
Input Port Group Description:

DtStringInputPort* DtGroundCollisionAvoidanceController::myFollowEntityInputPort [protected]

Input Port Name: follow-entity-name
Input Port Description: Check this port to see if any possible collision is with the entity we're suppose to follow
Input Port Range:
Input Port Default Value:
.

DtBooleanOutputPort* DtGroundCollisionAvoidanceController::myCollisionPort [protected]

Output Port Name: collision
Output Port Description: Specifies if there's a collision occuring Output Port Range:
Output Group Parent:
.

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The documentation for this class was generated from the following file:

• include/vrfmodel/gndColAvoid.h