maspack.spatialmotion

Class PlanarCoupling

java.lang.Object

maspack.spatialmotion.RigidBodyCoupling

maspack.spatialmotion.PlanarCoupling

public class PlanarCoupling
extends RigidBodyCoupling

Field Summary

Fields inherited from class maspack.spatialmotion.RigidBodyCoupling

BILATERAL, LINEAR, ROTARY, useNewDerivatives

Constructor Summary

Constructors

Constructor and Description
PlanarCoupling()

Method Summary

Modifier and Type	Method and Description
void	getConstraintInfo(maspack.spatialmotion.RigidBodyCoupling.ConstraintInfo[] info, RigidTransform3d TGD, RigidTransform3d TCD, RigidTransform3d XERR, boolean setEngaged) Computes the constraint frame G and the associated constraint information.
Vector3d	getNormal() Returns the normal associated with this coupling.
void	getNormal(Vector3d nrm)
void	initializeConstraintInfo(maspack.spatialmotion.RigidBodyCoupling.ConstraintInfo[] info)
boolean	isUnilateral()
int	maxUnilaterals() Returns the maximum number of unilateral constraints associated with this coupling.
int	numBilaterals() Returns the number of bilateral constraints associated with this coupling.
void	projectToConstraint(RigidTransform3d TGD, RigidTransform3d TCD) Computes the frame G on the constraint surface which is closest to a given frame C.
void	setNormal(Vector3d nrm)
void	setUnilateral(boolean unilateral)
void	transformGeometry(GeometryTransformer gt, RigidTransform3d TFW, RigidTransform3d TDW) Transforms the geometry of this coupling, in response to an affine transform X applied in world coordinates.

Methods inherited from class maspack.spatialmotion.RigidBodyCoupling

findNearestAngle, getAuxState, getBilateralConstraints, getBilateralForceG, getBilateralImpulses, getBreakAccel, getBreakSpeed, getCompliance, getConstraint, getConstraintInfo, getContactDistance, getDamping, getInitialAuxState, getUnilateralConstraints, getUnilateralForceG, getUnilateralImpulses, maxConstraints, numUnilaterals, printConstraintInfo, scaleDistance, setAuxState, setBilateralImpulses, setBreakAccel, setBreakSpeed, setCompliance, setContactDistance, setDamping, setDistanceAndZeroDerivative, setDistancesAndZeroDerivatives, setUnilateralImpulses, skipAuxState, updateBodyStates, updateConstraintsFromC, updateUnilateralConstraints, zeroImpulses

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

PlanarCoupling

public PlanarCoupling()

Method Detail

setUnilateral

public void setUnilateral(boolean unilateral)

isUnilateral

public boolean isUnilateral()

getNormal

public void getNormal(Vector3d nrm)

getNormal

public Vector3d getNormal()

Returns the normal associated with this coupling. Should not be modified.

setNormal

public void setNormal(Vector3d nrm)

maxUnilaterals

public int maxUnilaterals()

Description copied from class: RigidBodyCoupling

Returns the maximum number of unilateral constraints associated with this coupling.

Specified by:

maxUnilaterals in class RigidBodyCoupling

Returns:

maximum number of unilateral constraints

numBilaterals

public int numBilaterals()

Description copied from class: RigidBodyCoupling

Returns the number of bilateral constraints associated with this coupling.

Specified by:

numBilaterals in class RigidBodyCoupling

Returns:

number of bilateral constraints

projectToConstraint

public void projectToConstraint(RigidTransform3d TGD,
                                RigidTransform3d TCD)

Description copied from class: RigidBodyCoupling

Computes the frame G on the constraint surface which is closest to a given frame C. The input consists of the transform from C to D.

Specified by:

projectToConstraint in class RigidBodyCoupling

Parameters:

TGD - returns the transform from G to D

TCD - transform from frame C to D

initializeConstraintInfo

public void initializeConstraintInfo(maspack.spatialmotion.RigidBodyCoupling.ConstraintInfo[] info)

Specified by:

initializeConstraintInfo in class RigidBodyCoupling

getConstraintInfo

public void getConstraintInfo(maspack.spatialmotion.RigidBodyCoupling.ConstraintInfo[] info,
                              RigidTransform3d TGD,
                              RigidTransform3d TCD,
                              RigidTransform3d XERR,
                              boolean setEngaged)

Description copied from class: RigidBodyCoupling

Computes the constraint frame G and the associated constraint information. G is determined by projecting C onto the constraint surface.

Information for each constraint wrench is returned through an array of ConstraintInfo objects supplied by the argument info. This array should have a fixed number of elements equal to the number of bilateral constraints plus the maximum number of unilateral constraints. Bilateral constraints appear first, followed by the unilateral constraints. Constraint wrenches and their derivatives (with respect to frame G) are set within the fields wrenchC and dotWrenchC, repsectively. Distances to set within the distance; each of these should be the dot product of the wrench with the linearization of the constraint error TCG. For computing wrench derivatives, this method may use myVelBA, which gives the current velocity of B with repsect to A, in coordinate frame D. Information only needs to be returned for constraints which are potentially active, or engaged. Constraints which are engaged have their ConstraintInfo.engaged field set to a non-zero value. Bilateral constraints are always engaged, and their ConstraintInfo.engaged field is automatically set to 1 by the system. For unilateral constraints, the determination of whether or not the constraint is engaged, and the setting of the engaged field, should be done by this method if the argument setEngaged is true. Otherwise, if setEngaged is false, the method should take the engaged settings as given. Constraints which are engaged are those which are returned by the calls getBilateralConstraints or getUnilateralConstraints.

Specified by:

getConstraintInfo in class RigidBodyCoupling

Parameters:

info - used to return information for each possible constraint wrenches

TGD - returns the transform from G to D

TCD - transform from operation frame C to D

XERR - TODO

setEngaged - if true, this method should determine if the constraint is engaged.

transformGeometry

public void transformGeometry(GeometryTransformer gt,
                              RigidTransform3d TFW,
                              RigidTransform3d TDW)

Description copied from class: RigidBodyCoupling

Transforms the geometry of this coupling, in response to an affine transform X applied in world coordinates. In order to facilitate the application of this transform, this method also provides the current transforms from the C and D frames to world coordinates. It also provides the rotational component Ra of X.M, which should be determined from the left polar decomposition of X.M:

 X.M = P Ra
 

Given these arguments, a point p of the coupling defined with respect to frame D would transform according to

 p' = TDW.R^T Ra^T X.M TDW.R p
 

which is equivalent to transforming p to world coordinates (using TDW), applying X, and then transforming back to D using the modified TDW produced by applying X.

Overrides:

transformGeometry in class RigidBodyCoupling

Parameters:

gt - transformer implementing the transformation

TFW - current transform from C to world

TDW - current transform from D to world