Workspace

Classes
class	gpSAHandInfo
Functions
int	gpSAHfinger_forward_kinematics (double length1, double length2, double length3, double q1, double q2, double q3, p3d_vector3 position, p3d_vector3 normal)
int	gpSAHfinger_outer_workspace (gpSAHandInfo data, double dq, std::vector< gpVector3D > &points, std::vector< gpVector3D > &normals)
int	gpDraw_SAHfinger_outer_workspace (gpSAHandInfo data, double dq)
int	gpSAHfinger_workspace (gpSAHandInfo data, double dq, std::vector< gpVector3D > &points)
int	gpSAHfinger_workspace_approximation (gpSAHandInfo data, double dq, double dr, unsigned int nb_spheres_max, std::vector< gpSphere > &spheres)

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Detailed Description

This module implements some structures and functions to compute the approximation of the workspace of a finger of the Schunk Anthropomorphic Hand. The workspace is approximated as a set of spheres striclty included inside it.

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Function Documentation

int gpDraw_SAHfinger_outer_workspace	(	gpSAHandInfo	data,
		double	dq
	)

Draws the outer envelope of the workspace of a SAHand finger as a point cloud.

Parameters:

data	geometrical info about the finger
dq	discretization step of the joint parameters (in radians)

Returns:

GP_OK in case of success, GP_ERROR otherwise

int gpSAHfinger_forward_kinematics	(	double	length1,
		double	length2,
		double	length3,
		double	q1,
		double	q2,
		double	q3,
		p3d_vector3	position,
		p3d_vector3	normal
	)

Computes the position of the fingertip center point of the Schunk Anthropomorphic Hand finger. NB: The coupling between the 3rd and 4th joints is taken into account in the computation.

Parameters:

length1	length of the first phalanx
length2	length of the second phalanx
length3	length of the third phalanx
q1	first joint parameter (controls the (palm)-(proximal phalanx) joint first DOF (abduction))
q2	second joint (controls the (palm)-(proximal phalanx) joint second DOF (subduction))
q3	third joint parameter (controls the DOFs of the last two joints that are coupled)
position	the computed position of the fingertip center
normal	a vector giving the direction of the fingertip contact surface (orthogonal to the medial axis of the distal phalanx and directed towards the inside of the hand)

Returns:

GP_OK in case of success, GP_ERROR otherwise

int gpSAHfinger_outer_workspace	(	gpSAHandInfo	data,
		double	dq,
		std::vector< gpVector3D > &	points,
		std::vector< gpVector3D > &	normals
	)

Computes the outer envelope of the workspace of a SAHand finger as a point cloud.

Parameters:

data	geometrical info about the finger
dq	discretization step of the joint parameters (in radians)
points	computed point cloud
normal	fingertip surface normal at each point of the workspace

Returns:

GP_OK in case of success, GP_ERROR otherwise

int gpSAHfinger_workspace	(	gpSAHandInfo	data,
		double	dq,
		std::vector< gpVector3D > &	points
	)

Computes the workspace of a SAHand finger as a point cloud.

Parameters:

data	geometrical info about the finger
dq	discretization step of the joint parameters (in radians)
points	computed point cloud

Returns:

GP_OK in case of success, GP_ERROR otherwise

int gpSAHfinger_workspace_approximation	(	gpSAHandInfo	data,
		double	dq,
		double	dr,
		unsigned int	nb_spheres_max,
		std::vector< gpSphere > &	spheres
	)

Computes an approximation of the SAHand finger workspace as a set of spheres. All the spheres are completely included in the real workspace. The function builds a set of points inside the workspace (inner points) and a set of points on the workspace boundary (boundary points). The minimal distance from each inner point to the boundary points is computed. The first sphere center is the inner point with the maximal distance (that will be the sphere radius). All the inner points that are inside the sphere are removed. The new distance of each remaining points is the minimum of the old distance and the distance from the point to the sphere. The new sphere center is the inner point with the maximal distance and the algorithm continues with the same principle until the maximal number is reached ro the last computed sphere radius is smaller than the given threshold.

Parameters:

data	geometrical info about the finger
dq	discretization step of the joint parameters (in radians). Do not use less than ~2 degrees (pi/180 rads) to avoid memory overload and excessive computation time.
dr	the algorithm will end when it has found a sphere with radius < dr
nb_spheres_max	maximal number of spheres that will be computed
spheres	computed sphere set

Returns:

GP_OK in case of success, GP_ERROR otherwise