maspack.spatialmotion

Class SegmentedPlanarCoupling

java.lang.Object

maspack.spatialmotion.RigidBodyCoupling

maspack.spatialmotion.SegmentedPlanarCoupling

public class SegmentedPlanarCoupling
extends RigidBodyCoupling

Field Summary

Fields inherited from class maspack.spatialmotion.RigidBodyCoupling

BILATERAL, LINEAR, ROTARY, useNewDerivatives

Constructor Summary

Constructors

Constructor and Description
SegmentedPlanarCoupling()
SegmentedPlanarCoupling(double[] segs)

Method Summary

Modifier and Type	Method and Description
Plane	closestPlane(Point3d p) Returns the plane closest to a specified point in the D coordinate frame.
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.
java.util.ArrayList<Plane>	getPlanes() Returns a list of the planes in frame D.
java.util.ArrayList<Point3d>	getSegmentPoints() Returns a list of points describing the piecewise linear curve in the D frame x-z plane which defines the plane segments.
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.
int	numPlanes() Returns the number of planar segments 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	scaleDistance(double s)
void	setSegments(double[] segs) Sets the plane segments associated with this SegmentedPlanarCoupling.
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, 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

SegmentedPlanarCoupling

public SegmentedPlanarCoupling()

SegmentedPlanarCoupling

public SegmentedPlanarCoupling(double[] segs)

Method Detail

getSegmentPoints

public java.util.ArrayList<Point3d> getSegmentPoints()

Returns a list of points describing the piecewise linear curve in the D frame x-z plane which defines the plane segments. These returned points are read-only and should not be modified by the caller.

Returns:

points defining the plane segments (should not be modified)

getPlanes

public java.util.ArrayList<Plane> getPlanes()

Returns a list of the planes in frame D. The returned planes are read-only and should not be modified by the caller.

Returns:

plane segments (should not be modified)

numPlanes

public int numPlanes()

Returns the number of planar segments associated with this coupling.

Returns:

number of planes

setUnilateral

public void setUnilateral(boolean unilateral)

isUnilateral

public boolean isUnilateral()

setSegments

public void setSegments(double[] segs)

Sets the plane segments associated with this SegmentedPlanarCoupling. The segments are defined by a sequence of x-z coordinate pairs in the D coordinate frame. The number of segments equals the number of pairs minus one, so there must be at least two pairs (which would define a single plane). Segments are assumed to be contiguous, and the normal for each is defined by u X y, where u is a vector in the direction of the segment (from first to last coordinate pair) and y is the direction of the D frame y axis. The first and last plane segments are assumed to extend to infinity.

Parameters:

segs - x-z coordinate pairs defining the segments

closestPlane

public Plane closestPlane(Point3d p)

Returns the plane closest to a specified point in the D coordinate frame.

Parameters:

p - point to find nearest plane to

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.

scaleDistance

public void scaleDistance(double s)

Overrides:

scaleDistance in class RigidBodyCoupling

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