IKGoal Struct Reference

A structure defining a link's desired configuration for IK. More...

#include <IK.h>

Public Types
enum	PosConstraint { PosNone =0, PosPlanar =1, PosLinear =2, PosFixed =3 }
enum	RotConstraint { RotNone =0, RotTwoAxis =1, RotAxis =2, RotFixed =3 }

Public Member Functions
void	SetFixedPosition (const Vector3 &pos)
void	SetPlanarPosition (const Vector3 &point, const Vector3 &normal)
void	SetLinearPosition (const Vector3 &point, const Vector3 &direction)
void	SetFreePosition ()
	Removes the position constraint.
void	SetFixedRotation (const Matrix3 &R)
	Contrains the link to have a fixed rotation matrix.
void	SetFixedRotation (const Vector3 &mR)
	Contrains the link to have a fixed rotation moment.
void	SetAxisRotation (const Vector3 &localAxis, const Vector3 &worldAxis)
void	SetFreeRotation ()
	Removes the rotation constraint.
void	SetFixedTransform (const RigidTransform &T)
	Sets a fixed goal transformation.
void	SetFromPoints (const std::vector< Vector3 > &localpos, const std::vector< Vector3 > &worldpos, Real degeneracyTol=Epsilon)
void	RemovePositionAxis (const Vector3 &axis)
	Removes the position constraint through this axis.
void	RemoveRotationAxis (const Vector3 &axis)
	Removes the rotation constraint about the axis.
void	RemoveRotationAxis (const Vector3 &p, const Vector3 &axis)
	Removes the rotation constraint about the axis through the point p.
void	Transform (const RigidTransform &T)
	Inplace transformation of the goal position/orientation.
void	TransformLocal (const RigidTransform &T)
	Inplace transformation of the local position/orientation.
void	GetError (const RigidTransform &Trel, Real posErr[3], Real rotErr[3]) const
void	GetFixedGoalRotation (Matrix3 &R) const
void	GetFixedGoalTransform (RigidTransform &T) const
void	GetBaseEdgeRotation (Matrix3 &R0) const
void	GetEdgeGoalTransform (Real theta, RigidTransform &T) const
void	GetClosestGoalTransform (const RigidTransform &T0, RigidTransform &T) const
void	MatchGoalTransform (const RigidTransform &Trel)

Static Public Member Functions
static int	NumDims (PosConstraint c)
	Returns the number of operational space dof's of the given constraint.
static int	NumDims (RotConstraint c)

Public Attributes
int	link
	Robot link index.
int	destLink
	Desintation link index (-1 means world frame)
PosConstraint	posConstraint
	Position terms:
Vector3	localPosition
	End effector position in the local frame.
Vector3	endPosition
	The desired end effector position.
Vector3	direction
RotConstraint	rotConstraint
	Rotation terms:
Vector3	localAxis
	If in axis-constrained rotation, the local rot axis.
Vector3	endRotation

Detailed Description

A structure defining a link's desired configuration for IK.

Position and/or rotation can be constrained, as well as individual components of each.

Member Function Documentation

void IKGoal::GetClosestGoalTransform	(	const RigidTransform &	T0,
		RigidTransform &	T
	)		const

Gets a transformation T that satisfies the IK goal's constraints, and is closest to the transform T0. Useful for non-fixed IKGoals.

References Math3D::Line3D::closestPoint(), Math3D::GetCanonicalBasis(), GetMinimalRotation(), and Math3D::Plane3D::project().

void IKGoal::GetError	(	const RigidTransform &	Trel,
		Real	posErr[3],
		Real	rotErr[3]
	)		const

Returns the error in the current configuration given the current relative transform between link -> destlink

References destLink, direction, endPosition, endRotation, Math3D::Vector3::getOrthogonalBasis(), Math::IsFinite(), link, localAxis, localPosition, posConstraint, and rotConstraint.

Referenced by EvalIKError(), IntersectGoals(), and IsReachableGoal().

void IKGoal::MatchGoalTransform

(

const RigidTransform &

Trel

)

sets the endPosition / endRotation values so that if the current relative transform between the link and its target is Trel, the objective's error is 0

References Math3D::RigidTransform::mul().

void IKGoal::SetAxisRotation	(	const Vector3 &	localAxis,
		const Vector3 &	worldAxis
	)

Contrains the link's orientation so that localAxis is mapped onto worldAxis

void IKGoal::SetFixedPosition ( const Vector3 &  pos )

inline

Contrains localPosition to be fixed at pos. NOTE: localPosition is not set here!

void IKGoal::SetFromPoints	(	const std::vector< Vector3 > &	localpos,
		const std::vector< Vector3 > &	worldpos,
		Real	degeneracyTol = Epsilon
	)

Fits a constraint that maps the local positions onto the world positions. If 0 points are specified, the constraint is free. If the points are all equal, then the constraint is a point constraint. If the points lie on a line, then the constraint is a hinge constraint.

References Math3D::FitFrames(), GetMinimalRotation(), GetRotationAboutLocalPoint(), and Math::IsInf().

Referenced by IntersectGoals().

void IKGoal::SetLinearPosition	(	const Vector3 &	point,
		const Vector3 &	direction
	)

Contrains localPosition to lie along a line passing through point with direction normal. NOTE: localPosition is not set here!

void IKGoal::SetPlanarPosition	(	const Vector3 &	point,
		const Vector3 &	normal
	)

Contrains localPosition to lie along a plane passing through point with normal normal. NOTE: localPosition is not set here!

Member Data Documentation

Vector3 IKGoal::direction

For plane position constraints, the normal of the plane.
For line position constraints, the direction of the line.

Referenced by EvalIKGoalDeriv(), GetError(), and IntersectGoals().

Vector3 IKGoal::endRotation

The desired end effector rotation, that is, for: Axis-constrained rotation: the desired axis. Fixed rotation: the moment of the desired rotation R=e^[endRotation]

Referenced by EvalIKGoalDeriv(), GetError(), IntersectGoals(), IsReachableGoal(), and JointStructure::SolveWorkspaceBounds().

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The documentation for this struct was generated from the following files:

• IK.h
• IK.cpp