The function returns a relative transformation between the two "closest" convex shapes it contains. More...

#include <hpp/constraints/convex-shape-contact.hh>

Inheritance diagram for hpp::constraints::ConvexShapeContact:

Collaboration diagram for hpp::constraints::ConvexShapeContact:

Classes
struct	ForceData
	Represents a contact When supportJoint is NULL, the contact is with the environment. More...

Public Types
enum	ContactType { POINT_ON_PLANE, LINE_ON_PLANE, PLANE_ON_PLANE }
	The type of contact between each pair (object shape, floor shape). More...

Public Member Functions
	ConvexShapeContact (const std::string &name, const DevicePtr_t &robot)
	Constructor. More...

void	addObjectTriangle (const fcl::TriangleP &t, const JointPtr_t &joint) HPP_CONSTRAINTS_DEPRECATED
	Use addObject(const ConvexShape&) instead. More...

void	addFloorTriangle (const fcl::TriangleP &t, const JointPtr_t &joint) HPP_CONSTRAINTS_DEPRECATED
	Use addFloor(const ConvexShape&) instead. More...

void	addObject (const ConvexShape &t)
	Add a ConvexShape as an object. More...

void	addFloor (const ConvexShape &t)
	Add a ConvexShape as a floor. More...

void	setNormalMargin (const value_type &margin)
	Set the normal margin, i.e. More...

std::vector< ForceData >	computeContactPoints (ConfigurationIn_t q, const value_type &normalMargin) const
	Compute the contact points. More...

std::ostream &	print (std::ostream &o) const
	Display object in a stream. More...

Public Member Functions inherited from hpp::constraints::DifferentiableFunction
virtual	~DifferentiableFunction ()

LiegroupElement	operator() (vectorIn_t argument) const
	Evaluate the function at a given parameter. More...

void	value (LiegroupElementRef result, vectorIn_t argument) const
	Evaluate the function at a given parameter. More...

void	jacobian (matrixOut_t jacobian, vectorIn_t argument) const
	Computes the jacobian. More...

const ArrayXb &	activeParameters () const
	Returns a vector of booleans that indicates whether the corresponding configuration parameter influences this constraints. More...

const ArrayXb &	activeDerivativeParameters () const
	Returns a vector of booleans that indicates whether the corresponding velocity parameter influences this constraints. More...

size_type	inputSize () const
	Get dimension of input vector. More...

size_type	inputDerivativeSize () const
	Get dimension of input derivative vector. More...

LiegroupSpacePtr_t	outputSpace () const
	Get output element. More...

size_type	outputSize () const
	Get dimension of output vector. More...

size_type	outputDerivativeSize () const
	Get dimension of output derivative vector. More...

const std::string &	name () const
	Get function name. More...

std::string	context () const

void	context (const std::string &c)

void	finiteDifferenceForward (matrixOut_t jacobian, vectorIn_t arg, DevicePtr_t robot=DevicePtr_t(), value_type eps=std::sqrt(Eigen::NumTraits< value_type >::epsilon())) const
	Approximate the jacobian using forward finite difference. More...

void	finiteDifferenceCentral (matrixOut_t jacobian, vectorIn_t arg, DevicePtr_t robot=DevicePtr_t(), value_type eps=std::sqrt(Eigen::NumTraits< value_type >::epsilon())) const
	Approximate the jacobian using forward finite difference. More...

Static Public Member Functions
static ConvexShapeContactPtr_t	create (const std::string &name, const DevicePtr_t &robot)

static ConvexShapeContactPtr_t	create (const DevicePtr_t &robot)

Friends
class	ConvexShapeContactComplement

Additional Inherited Members
Protected Member Functions inherited from hpp::constraints::DifferentiableFunction
	DifferentiableFunction (size_type sizeInput, size_type sizeInputDerivative, size_type sizeOutput, std::string name=std::string())
	Concrete class constructor should call this constructor. More...

	DifferentiableFunction (size_type sizeInput, size_type sizeInputDerivative, const LiegroupSpacePtr_t &outputSpace, std::string name=std::string())
	Concrete class constructor should call this constructor. More...

virtual void	impl_compute (LiegroupElementRef result, vectorIn_t argument) const =0
	User implementation of function evaluation. More...

virtual void	impl_jacobian (matrixOut_t jacobian, vectorIn_t arg) const =0

Protected Attributes inherited from hpp::constraints::DifferentiableFunction
size_type	inputSize_
	Dimension of input vector. More...

size_type	inputDerivativeSize_
	Dimension of input derivative. More...

LiegroupSpacePtr_t	outputSpace_
	Dimension of output vector. More...

ArrayXb	activeParameters_
	Initialized to true by this class. More...

ArrayXb	activeDerivativeParameters_
	Initialized to true by this class. More...

Detailed Description

The function returns a relative transformation between the two "closest" convex shapes it contains.

Two set of convex shapes can be given to this class:

a set of object contact surfaces, \( (o_i)_{i \in I } \), which can be in contact with the environment,
a set of floor contact surfaces, \( (f_j)_{j \in J } \), which can support objects.

The distance \( d_{i,j} = d (o_i, f_j) \) between object surface \(o_i\) and environment surface \( f_j \) is defined by:

\begin{equation*} d(i,j)^2 = \left\lbrace \begin{array}{cl} d_{\parallel}^2 + d_{\perp}^2 &, \text{ if } d_{\parallel} > 0 \\ d_{\perp}^2 &, \text{ otherwise} \end{array} \right. \end{equation*}

where

\(P (C_{o_i}, f_j)\) is the projection of the center \(o_i\) onto the plane containing \( f_j \),
\(\textbf{n}_{f_j}\) is the normal of \( f_j \),
\(d_{\parallel} = d(f_j, P (C_{o_i}, f_j))\) is the distance returned by ConvexShape::distance,
\(d_{\perp} = \textbf{n}_{f_j}.C_{f_j}P(C_{o_i}, f_j)\) is the distance along the normal of \( f_j \),

The function first selects the pair \((o_i,f_j)\) with shortest distance. \(o_i\) is inside \(f_j\) if \(d(i,j) < 0\). It returns a value that depends on the contact types:

Contact type	Inside	Outside
ConvexShapeContact::POINT_ON_PLANE	\((x+m,0,0,0,0)\)	\((x+m,y,z,0,0)\)
ConvexShapeContact::LINE_ON_PLANE (Unsupported)	\((x+m,0,0,0,rz)\)	\((x+m,y,z,0,rz)\)
ConvexShapeContact::PLANE_ON_PLANE	\((x+m,0,0,ry,rz)\)	\((x+m,y,z,ry,rz)\)

where

\(m\) is the normal margin (used to avoid collisions),
\(x,y,z,rx,ry,rz\) represents the output of the RelativeTransformation between the element of the pair.

See also: ConvexShapeContactComplement

Member Enumeration Documentation

enum hpp::constraints::ConvexShapeContact::ContactType

The type of contact between each pair (object shape, floor shape).

Enumerator
POINT_ON_PLANE	The object shape is a single point,.
LINE_ON_PLANE	The object shape degenerates to a line,.
PLANE_ON_PLANE	The object shape is included in a plane and none of the above case apply.

Constructor & Destructor Documentation

hpp::constraints::ConvexShapeContact::ConvexShapeContact	(	const std::string &	name,
		const DevicePtr_t &	robot
	)

Constructor.

Parameters

name	name of the ConvexShapeContact constraint,
robot	the robot the constraints is applied to,

Member Function Documentation

void hpp::constraints::ConvexShapeContact::addFloor ( const ConvexShape & t )

Add a ConvexShape as a floor.

The convex shape will be reverted using ConvexShape::reverse so that the normal points inside the floor object.

void hpp::constraints::ConvexShapeContact::addFloorTriangle	(	const fcl::TriangleP &	t,
		const JointPtr_t &	joint
	)

Use addFloor(const ConvexShape&) instead.

Add a triangle to the floor contact surface

Parameters

t	triangle, joint Joint to which the triangle is attached if the contact surface belongs to a robot.

void hpp::constraints::ConvexShapeContact::addObject ( const ConvexShape & t )

Add a ConvexShape as an object.

void hpp::constraints::ConvexShapeContact::addObjectTriangle	(	const fcl::TriangleP &	t,
		const JointPtr_t &	joint
	)

Use addObject(const ConvexShape&) instead.

Add a triangle to the object contact surface

Parameters

t	triangle,
joint	Joint to which the triangle is attached.

std::vector<ForceData> hpp::constraints::ConvexShapeContact::computeContactPoints	(	ConfigurationIn_t	q,
		const value_type &	normalMargin
	)		const

Compute the contact points.

static ConvexShapeContactPtr_t hpp::constraints::ConvexShapeContact::create	(	const std::string &	name,
		const DevicePtr_t &	robot
	)

static

static ConvexShapeContactPtr_t hpp::constraints::ConvexShapeContact::create ( const DevicePtr_t & robot )

static

std::ostream& hpp::constraints::ConvexShapeContact::print ( std::ostream & o ) const

virtual

Display object in a stream.

Reimplemented from hpp::constraints::DifferentiableFunction.

void hpp::constraints::ConvexShapeContact::setNormalMargin ( const value_type & margin )

Set the normal margin, i.e.

the desired distance between matching object and nd floor shapes. Default to 0

Friends And Related Function Documentation

friend class ConvexShapeContactComplement

friend

Classes

Public Types

Public Member Functions

Static Public Member Functions

Friends

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation

Friends And Related Function Documentation