maspack.spatialmotion

Class SphericalCoupling

java.lang.Object

maspack.spatialmotion.RigidBodyCoupling

maspack.spatialmotion.SphericalCoupling

public class SphericalCoupling
extends RigidBodyCoupling

Implements a three DOF spherical coupling. Frames C and D share a common origin and are otherwise free to rotate about each other. Travel restrictions can be placed on this coupling by bounding either the maximum tilt of the z axis, or the maximum total rotation. Bounds on the maximum total rotation can be weighted by the rotation direction, so that the maximum rotations about the x, y, and z axes are different.

Field Summary

Fields

Modifier and Type	Field and Description
boolean	applyEuler
static int	ROTATION_LIMIT
static int	RPY_LIMIT
static int	TILT_LIMIT

Fields inherited from class maspack.spatialmotion.RigidBodyCoupling

BILATERAL, LINEAR, ROTARY, useNewDerivatives

Constructor Summary

Constructors

Constructor and Description
SphericalCoupling()

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.
double	getMaximumRotation() Returns the maximum total rotation for this coupling.
void	getMaximumRotation(double[] maxRot) Returns the maximum total rotation for each axis.
double	getMaximumTilt() Returns the maximum value of theta for this revolute coupling.
void	getPitchRange(double[] minmax) Gets the minimum and maximum values for the coupling's pitch angle (in radians).
int	getRangeType()
void	getRollRange(double[] minmax) Gets the minimum and maximum values for the coupling's roll angle (in radians).
void	getRpy(Vector3d angs, RigidTransform3d TGD)
void	getYawRange(double[] minmax) Gets the minimum and maximum values for the coupling's yaw angle (in radians).
void	initializeConstraintInfo(maspack.spatialmotion.RigidBodyCoupling.ConstraintInfo[] info)
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	setMaximumRotation(double max) Sets the maximum total rotation for this coupling.
void	setMaximumRotation(double maxx, double maxy, double maxz) Sets the maximum total rotation about the x, y, and z axes.
void	setMaximumTilt(double max) Sets the maximum tilt for this coupling.
void	setPitchRange(double min, double max) Sets the minimum and maximum values for the coupling's pitch angle (in radians).
void	setRangeType(int type)
void	setRollRange(double min, double max) Sets the minimum and maximum values for the coupling's roll angle (in radians).
void	setRpy(RigidTransform3d TGD, Vector3d angs)
void	setYawRange(double min, double max) Sets the minimum and maximum values for the coupling's yaw angle (in radians).

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, transformGeometry, updateBodyStates, updateConstraintsFromC, updateUnilateralConstraints, zeroImpulses

Methods inherited from class java.lang.Object

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

Field Detail

applyEuler

public boolean applyEuler

TILT_LIMIT

public static final int TILT_LIMIT

See Also:

Constant Field Values

ROTATION_LIMIT

public static final int ROTATION_LIMIT

See Also:

Constant Field Values

RPY_LIMIT

public static final int RPY_LIMIT

See Also:

Constant Field Values

Constructor Detail

SphericalCoupling

public SphericalCoupling()

Method Detail

getRangeType

public int getRangeType()

setRangeType

public void setRangeType(int type)

setMaximumRotation

public void setMaximumRotation(double max)

Sets the maximum total rotation for this coupling. This will only have an effect if the current range type is ROTATION_LIMIT. The maximum must be greater than 0, and will be clipped to the range (0, PI]. Setting the maximum to PI will remove the range restriction.

Parameters:

max - maximum total rotation

setMaximumRotation

public void setMaximumRotation(double maxx,
                               double maxy,
                               double maxz)

Sets the maximum total rotation about the x, y, and z axes. This will only have an effect if the current range type is ROTATION_LIMIT. For a general orientation, the maximum rotation angle will be computed from the length of the rotation axis weighted by the maximum values along each principal axis.

Each maximum must be greater than 0, and will be clipped to the range (0, PI]. Setting all maximums to PI will remove the range restriction.

Parameters:

maxx - maximum total rotation about x

maxy - maximum total rotation about y

maxz - maximum total rotation about z

getMaximumRotation

public void getMaximumRotation(double[] maxRot)

Returns the maximum total rotation for each axis.

Parameters:

maxRot - returns the maximum rotation for each axis

getMaximumRotation

public double getMaximumRotation()

Returns the maximum total rotation for this coupling. If separate maximum rotations have been specified for each axis, then the maximum rotation for the x axis is returned.

Returns:

the maximum rotation for this coupling, or for the x axis if separate limits have been specified for each axis

setRollRange

public void setRollRange(double min,
                         double max)

Sets the minimum and maximum values for the coupling's roll angle (in radians). These only have an effect if the current range type is RPY_LIMIT.

Parameters:

min - Minimum roll angle

max - Maximum roll angle

getRollRange

public void getRollRange(double[] minmax)

Gets the minimum and maximum values for the coupling's roll angle (in radians).

Parameters:

minmax - used to return the minimum and maximum values

See Also:

setRollRange(double, double)

setPitchRange

public void setPitchRange(double min,
                          double max)

Sets the minimum and maximum values for the coupling's pitch angle (in radians). These values only have an effect if the current range type is RPY_LIMIT.

Parameters:

min - Minimum pitch angle

max - Maximum pitch angle

getPitchRange

public void getPitchRange(double[] minmax)

Gets the minimum and maximum values for the coupling's pitch angle (in radians).

Parameters:

minmax - used to return the minimum and maximum values

See Also:

setPitchRange(double, double)

setYawRange

public void setYawRange(double min,
                        double max)

Sets the minimum and maximum values for the coupling's yaw angle (in radians). These only have an effect if the current range type is RPY_LIMIT.

Parameters:

min - Minimum yaw angle

max - Maximum yaw angle

getYawRange

public void getYawRange(double[] minmax)

Gets the minimum and maximum values for the coupling's yaw angle (in radians).

Parameters:

minmax - used to return the minimum and maximum values

See Also:

setYawRange(double, double)

setMaximumTilt

public void setMaximumTilt(double max)

Sets the maximum tilt for this coupling. The tilt is the angle between the initial and current z axis. This will only have an effect if the current range type is TILT_LIMIT. The maximum must be greater than 0, and will be clipped to the range (0, PI].

Parameters:

max - maximum value for theta

getMaximumTilt

public double getMaximumTilt()

Returns the maximum value of theta for this revolute coupling.

Returns:

maximum value for theta

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

getRpy

public void getRpy(Vector3d angs,
                   RigidTransform3d TGD)

setRpy

public void setRpy(RigidTransform3d TGD,
                   Vector3d angs)

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.