Defines a bilateral constraint (a joint) More...

#include <Joint.h>

Inheritance diagram for JOINT:

Public Types
enum	ConstraintType { eUnknown, eExplicit, eImplicit }

enum	DOFs { DOF_1 =0, DOF_2 =1, DOF_3 =2, DOF_4 =3, DOF_5 =4, DOF_6 =5 }

Public Member Functions
	JOINT ()
	Initializes the joint. More...

virtual const std::vector < SVELOCITY > &	get_spatial_axes ()
	Gets the spatial axes for this joint. More...

void	add_force (const VECTORN &force)
	Adds a force to the joint.

void	reset_force ()
	Resets the force on the joint.

ConstraintType	get_constraint_type () const

void	set_constraint_type (ConstraintType type)
	Sets whether this constraint is implicit or explicit (or unknown)

boost::shared_ptr < ARTICULATED_BODY >	get_articulated_body ()
	Gets the articulated body corresponding to this body. More...

void	set_articulated_body (boost::shared_ptr< ARTICULATED_BODY > abody)
	Sets the articulated body corresponding to this body. More...

virtual void	set_inboard_link (boost::shared_ptr< RIGIDBODY > link, bool update_pose)

virtual void	set_outboard_link (boost::shared_ptr< RIGIDBODY > link, bool update_pose)

void	set_location (const VECTOR3 &p, boost::shared_ptr< RIGIDBODY > inboard, boost::shared_ptr< RIGIDBODY > outboard)

VECTOR3	get_location (bool use_outboard=false) const
	Gets the location of this joint. More...

virtual void	set_inboard_pose (boost::shared_ptr< const POSE3 > inboard_pose, bool update_joint_pose)

virtual void	set_outboard_pose (boost::shared_ptr< POSE3 > outboard_pose, bool update_joint_pose)

virtual void	update_spatial_axes ()
	Abstract method to update the local spatial axes. More...

virtual void	evaluate_constraints_dot (REAL C[])
	Evaluates the time derivative of the constraint equations.

virtual void	set_q_tare (const VECTORN &tare)

virtual const VECTORN &	get_q_tare () const

boost::shared_ptr< RIGIDBODY >	get_inboard_link () const
	Gets the inboard link for this joint.

boost::shared_ptr< RIGIDBODY >	get_outboard_link () const
	Gets the outboard link for this joint.

unsigned	get_index () const
	Gets the joint index (returns UINT_MAX if not set)

void	set_index (unsigned index)
	Sets the joint index. More...

unsigned	get_constraint_index () const
	Gets the constraint index for this joint.

void	set_constraint_index (unsigned idx)
	Sets the constraint index for this joint.

void	set_coord_index (unsigned index)
	Sets the coordinate index for this joint. More...

unsigned	get_coord_index () const
	Gets the starting coordinate index for this joint.

boost::shared_ptr< const POSE3 >	get_pose () const
	Gets the pose of this joint (relative to the inboard pose instead of the outboard pose as returned by get_pose_from_outboard())

boost::shared_ptr< const POSE3 >	get_pose_from_outboard () const
	Gets the pose of this joint relative to the outboard pose (rather than the inboard pose as returned by get_pose())

virtual bool	is_singular_config () const =0
	Gets whether this joint is in a singular configuration. More...

virtual unsigned	num_constraint_eqns () const
	Gets the number of constraint equations for this joint.

virtual void	evaluate_constraints (REAL C[])=0
	Evaluates the constraint equations for this joint. More...

virtual const std::vector < SVELOCITY > &	get_spatial_axes_dot ()=0
	Abstract method to get the spatial axes derivatives for this joint. More...

virtual boost::shared_ptr < const POSE3 >	get_induced_pose ()=0
	Abstract method to get the local transform for this joint. More...

virtual void	determine_q (VECTORN &q)=0
	Abstract method to determine the value of Q (joint position) from current transforms.

virtual unsigned	num_dof () const =0
	Gets the number of degrees-of-freedom for this joint.

virtual void	calc_constraint_jacobian (bool inboard, MATRIXN &Cq)=0
	Computes the constraint Jacobian for this joint with respect to the given body. More...

virtual void	calc_constraint_jacobian_dot (bool inboard, MATRIXN &Cq)=0
	Computes the time derivative of the constraint Jacobian for this joint with respect to the given body. More...

Public Member Functions inherited from Ravelin::virtual_enable_shared_from_this< JOINT >
boost::shared_ptr< JOINT >	shared_from_this ()

boost::shared_ptr< const JOINT >	shared_from_this () const

Public Attributes
std::string	joint_id
	The ID of this joint.

VECTORN	qdd
	The acceleration of this joint.

VECTORN	force
	The actuator force (user/controller sets this)

VECTORN	lambda
	Constraint forces calculated by forward dynamics.

VECTORN	q
	The position of this joint.

VECTORN	qd
	The velocity of this joint.

Protected Member Functions
void	calc_constraint_jacobian_numeric (bool inboard, MATRIXN &Cq)
	Computes the constraint jacobian with respect to a body numerically

bool	transform_jacobian (MATRIXN &J, bool use_inboard, MATRIXN &output)
	Transforms a Jacobian (if necessary) More...

void	invalidate_pose_vectors ()

boost::shared_ptr< const POSE3 >	get_inboard_pose ()

boost::shared_ptr< const POSE3 >	get_outboard_pose ()

virtual void	init_data ()
	Method for initializing all variables in the joint. More...

Protected Attributes
boost::shared_ptr< POSE3 >	_Fprime
	The frame induced by the joint.

boost::shared_ptr< POSE3 >	_F
	The frame of this joint.

boost::shared_ptr< POSE3 >	_Fb
	The frame of this joint backward from the outboard link.

std::vector< SVELOCITY >	_s
	The spatial axes (in joint frame) for the joint. More...

VECTORN	_q_tare
	The stored "tare" value for the initial joint configuration. More...

boost::weak_ptr< RIGIDBODY >	_inboard_link

boost::weak_ptr< RIGIDBODY >	_outboard_link

boost::weak_ptr< ARTICULATED_BODY >	_abody

ConstraintType	_constraint_type

unsigned	_joint_idx

unsigned	_coord_idx

unsigned	_constraint_idx

Detailed Description

Defines a bilateral constraint (a joint)

Constructor & Destructor Documentation

JOINT::JOINT ( )

Initializes the joint.

The inboard and outboard links are set to NULL.

References _F, _Fb, _Fprime, and _q_tare.

Member Function Documentation

virtual void JOINT::calc_constraint_jacobian	(	bool	inboard,
		MATRIXN &	Cq
	)

pure virtual

Computes the constraint Jacobian for this joint with respect to the given body.

Parameters

inboard	'true' if the Jacobian is to be computed w.r.t. the inboard link; 'false' for the outboard
Cq	a 6 x ndof matrix for the given body (on return)

Implemented in SPHERICALJOINT, UNIVERSALJOINT, FIXEDJOINT, PRISMATICJOINT, REVOLUTEJOINT, and PLANARJOINT.

virtual void JOINT::calc_constraint_jacobian_dot	(	bool	inboard,
		MATRIXN &	Cq
	)

pure virtual

Computes the time derivative of the constraint Jacobian for this joint with respect to the given body.

Parameters

inboard	'true' if the Jacobian is to be computed w.r.t. the inboard link; 'false' for the outboard
Cq	a 6 x ndof matrix for the given body (on return)

Implemented in SPHERICALJOINT, UNIVERSALJOINT, FIXEDJOINT, PRISMATICJOINT, REVOLUTEJOINT, and PLANARJOINT.

virtual void JOINT::evaluate_constraints ( REAL C[] )

pure virtual

Evaluates the constraint equations for this joint.

When the joint constraints are exactly satisfied, the result will be the zero vector.

Parameters

C	a vector of size num_constraint_eqns(); contains the evaluation (on return)

Note: only used by maximal-coordinate articulated bodies

Implemented in UNIVERSALJOINT, SPHERICALJOINT, FIXEDJOINT, PRISMATICJOINT, REVOLUTEJOINT, and PLANARJOINT.

Referenced by evaluate_constraints_dot().

boost::shared_ptr<ARTICULATED_BODY> JOINT::get_articulated_body ( )

inline

Gets the articulated body corresponding to this body.

Returns: a pointer to the articulated body, or NULL if this body is not a link an articulated body

virtual boost::shared_ptr<const POSE3> JOINT::get_induced_pose ( )

pure virtual

Abstract method to get the local transform for this joint.

The local transform for the joint transforms the coordinate frame attached to the joint center and aligned with the inner link frame.

Implemented in UNIVERSALJOINT, SPHERICALJOINT, FIXEDJOINT, PLANARJOINT, PRISMATICJOINT, and REVOLUTEJOINT.

VECTOR3 JOINT::get_location ( bool use_outboard = false ) const

Gets the location of this joint.

Parameters

use_outboard if true then the joint position is calculated using the outboard link rather than inboard link; the position will not be identical if the joint constraint is violated (therefore, this method will behave identically for reduced-coordinate articulated bodies)

References _F, and _Fb.

Referenced by REVOLUTEJOINT::evaluate_constraints().

const vector< SVELOCITY > & JOINT::get_spatial_axes ( )

virtual

Gets the spatial axes for this joint.

Spatial axes describe the motion of the joint. Note that for rftype = eLink, spatial axes are given in outboard link's frame.

Reimplemented in UNIVERSALJOINT, and SPHERICALJOINT.

References _s.

Referenced by SPHERICALJOINT::get_spatial_axes().

virtual const std::vector<SVELOCITY>& JOINT::get_spatial_axes_dot ( )

pure virtual

Abstract method to get the spatial axes derivatives for this joint.

Only applicable for reduced-coordinate articulated bodies

Implemented in PLANARJOINT, UNIVERSALJOINT, SPHERICALJOINT, FIXEDJOINT, PRISMATICJOINT, and REVOLUTEJOINT.

void JOINT::init_data ( )

protectedvirtual

Method for initializing all variables in the joint.

Sets the number of degrees-of-freedom for this joint.

This method should be called at the beginning of all constructors of all derived classes.

Note: resets all joint values (q) to zero

References _q_tare, _s, force, lambda, num_constraint_eqns(), num_dof(), q, qd, qdd, and VECTORN::set_zero().

Referenced by FIXEDJOINT::FIXEDJOINT(), PLANARJOINT::PLANARJOINT(), REVOLUTEJOINT::REVOLUTEJOINT(), and SPHERICALJOINT::SPHERICALJOINT().

virtual bool JOINT::is_singular_config ( ) const

pure virtual

Gets whether this joint is in a singular configuration.

Note: only used by reduced-coordinate articulated bodies

Implemented in SPHERICALJOINT, UNIVERSALJOINT, FIXEDJOINT, PRISMATICJOINT, REVOLUTEJOINT, and PLANARJOINT.

void JOINT::set_articulated_body ( boost::shared_ptr< ARTICULATED_BODY > abody )

inline

Sets the articulated body corresponding to this body.

Parameters

body	a pointer to the articulated body or NULL if this body is not a link in an articulated body

void JOINT::set_coord_index ( unsigned index )

inline

Sets the coordinate index for this joint.

This is set automatically by the articulated body. Users should not change this index or unknown behavior will result.

void JOINT::set_index ( unsigned index )

inline

Sets the joint index.

This is set automatically by the articulated body. Users should not change this index or unknown behavior will result.

bool JOINT::transform_jacobian	(	MATRIXN &	J,
		bool	use_inboard,
		MATRIXN &	output
	)

protected

Transforms a Jacobian (if necessary)

If the inboard/outboard link is part of an articulated body, transforms the Jacobian to the coordinates of that body.

Returns: true if any transformation is done (will be found in output)

References ARTICULATED_BODY::calc_jacobian(), get_inboard_link(), and get_outboard_link().

Referenced by PLANARJOINT::calc_constraint_jacobian(), FIXEDJOINT::calc_constraint_jacobian(), REVOLUTEJOINT::calc_constraint_jacobian(), and SPHERICALJOINT::calc_constraint_jacobian().

void JOINT::update_spatial_axes ( )

virtual

Abstract method to update the local spatial axes.

Only applicable for reduced-coordinate articulated bodies

Reimplemented in UNIVERSALJOINT, SPHERICALJOINT, FIXEDJOINT, PLANARJOINT, PRISMATICJOINT, and REVOLUTEJOINT.

References _s, get_pose(), and num_dof().

Referenced by FIXEDJOINT::update_spatial_axes(), PLANARJOINT::update_spatial_axes(), REVOLUTEJOINT::update_spatial_axes(), and SPHERICALJOINT::update_spatial_axes().

Member Data Documentation

VECTORN JOINT::_q_tare

protected

The stored "tare" value for the initial joint configuration.

The tare value is the value that the joint assumes in the an articulated body's initial configuration. This value is necessary so that- when the body's joints are set to the zero vector- the body re-enters the initial configuration.

Referenced by SPHERICALJOINT::get_axis(), PLANARJOINT::get_induced_pose(), REVOLUTEJOINT::get_induced_pose(), SPHERICALJOINT::get_rotation(), SPHERICALJOINT::get_spatial_axes(), SPHERICALJOINT::get_spatial_axes_dot(), init_data(), and JOINT().

std::vector<SVELOCITY> JOINT::_s

protected

The spatial axes (in joint frame) for the joint.

Spatial axes are used in the dynamics equations for reduced-coordinate articulated bodies only.

Referenced by SPHERICALJOINT::get_spatial_axes(), get_spatial_axes(), init_data(), REVOLUTEJOINT::update_spatial_axes(), PLANARJOINT::update_spatial_axes(), SPHERICALJOINT::update_spatial_axes(), and update_spatial_axes().

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

/home/drum/Ravelin.new/include/Ravelin/Joint.h
/home/drum/Ravelin.new/src/Joint.cpp

Public Types

Public Member Functions

Public Attributes

Protected Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation