Defines a joint used in articulated rigid body dynamics simulation. More...

#include <Joint.h>

Inheritance diagram for Moby::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...

	Joint (boost::weak_ptr< RigidBody > inboard, boost::weak_ptr< RigidBody > outboard)
	Initializes the joint with the specified inboard and outboard links. More...

void	set_location (const Point3d &p, RigidBodyPtr inboard, RigidBodyPtr outboard)
	Sets the location of this joint with specified inboard and outboard links.

Ravelin::VectorNd &	get_scaled_force (Ravelin::VectorNd &f)
	Gets the scaled actuator forces. More...

virtual void	save_to_xml (XMLTreePtr node, std::list< boost::shared_ptr< const Base > > &shared_objects) const
	Implements Base::save_to_xml()

virtual void	load_from_xml (boost::shared_ptr< const XMLTree > node, std::map< std::string, BasePtr > &id_map)
	Implements Base::load_from_xml()

virtual void	set_inboard_link (RigidBodyPtr link, bool update_pose)
	Sets the pointer to the inboard link for this joint (and updates the spatial axes, if the outboard link has been set)

virtual void	set_outboard_link (RigidBodyPtr link, bool update_pose)
	Sets the pointer to the outboard link for this joint. More...

void	set_articulated_body (ArticulatedBodyPtr abody)
	Sets the articulated body corresponding to this body. More...

ArticulatedBodyPtr	get_articulated_body ()
	Gets the articulated body corresponding to this body. More...

RigidBodyPtr	get_inboard_link () const
	Gets the inboard link for this joint.

RigidBodyPtr	get_outboard_link () const
	Gets the outboard link for this joint.

Public Member Functions inherited from Moby::Visualizable
	Visualizable (const Visualizable *v)

virtual void	update_visualization ()
	Updates the visualization using the appropriate transform. More...

void	set_visualization_relative_pose (const Ravelin::Pose3d &P)
	Sets the visualization relative pose.

virtual void	set_visualization_data (osg::Node *vdata)
	Sets the visualization data from a node.

virtual void	set_visualization_data (OSGGroupWrapperPtr vdata)
	Sets the visualization data from a OSGGroupWrapper.

osg::Group *	get_visualization_data () const
	Gets the visualization data for this object.

boost::shared_ptr< const Ravelin::Pose3d >	get_visualization_pose ()
	Gets the pose for this visualizable object.

Public Member Functions inherited from Moby::Base
	Base (const Base *b)

Public Attributes
Ravelin::VectorNd	lolimit
	The lower joint limit.

Ravelin::VectorNd	hilimit
	The upper joint limit.

double	limit_restitution
	The coefficient of restitution applied when this joint reaches a limit.

double	mu_fc
	The coulomb friction coefficient for this joint.

double	mu_fv
	The viscous friction coefficient for this joint.

double	compliant_layer_depth
	The depth of the compliant layer around the joint limit.

Public Attributes inherited from Moby::Base
boost::shared_ptr< void >	userdata
	Any relevant userdata.

std::string	id
	The unique ID for this object.

Protected Member Functions
void	determine_q_dot ()
	(Relatively slow) method for determining the joint velocity from current link velocities

virtual void	init_data ()
	Computes the constraint Jacobian for this joint with respect to the given body in Rodrigues parameters. More...

Friends
class	ArticulatedBody

Additional Inherited Members
Static Public Member Functions inherited from Moby::Visualizable
static osg::Group *	construct_from_node (boost::shared_ptr< const XMLTree > node, const std::map< std::string, BasePtr > &id_map)
	Utility method for load_from_xml() More...

Static Public Member Functions inherited from Moby::Base
template<class T >
static boost::shared_ptr< T >	clone (boost::shared_ptr< T > x)
	Static method for cloning a shared pointer.

Protected Attributes inherited from Moby::Visualizable
boost::shared_ptr < Ravelin::Pose3d >	_vF
	The relative pose.

OSGGroupWrapperPtr	_vizdata
	The underlying visualization data.

Detailed Description

Defines a joint used in articulated rigid body dynamics simulation.

Todo:: implement a rest position for q?

Member Enumeration Documentation

enum Moby::Joint::ConstraintType

The constraint type is implicit if constraint forces must be determined to hold the inner and outer links together and explicit otherwise.

Constructor & Destructor Documentation

Joint::Joint ( )

Initializes the joint.

The inboard and outboard links are set to NULL.

References Moby::Visualizable::_vF, compliant_layer_depth, limit_restitution, mu_fc, and mu_fv.

Joint::Joint	(	boost::weak_ptr< RigidBody >	inboard,
		boost::weak_ptr< RigidBody >	outboard
	)

Initializes the joint with the specified inboard and outboard links.

Note: does not set the inner joint for the outboard link or add the outboard as a child of the inboard link

References Moby::Visualizable::_vF, compliant_layer_depth, limit_restitution, mu_fc, and mu_fv.

Member Function Documentation

ArticulatedBodyPtr Joint::get_articulated_body ( )

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

VectorNd & Joint::get_scaled_force ( Ravelin::VectorNd & f )

Gets the scaled actuator forces.

Note: relevant only to reduced-coordinate articulated bodies

void Joint::init_data ( )

protectedvirtual

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

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

Parameters

body	the body with which the constraint Jacobian will be calculated; if the body is not either the inner or outer link, the constraint Jacobian will be a zero matrix
index	the index of the constraint equation for which to calculate
Cq	a vector that contains the corresponding column of the constraint Jacobian on returnComputes the time derivative of the constraint Jacobian for this joint with respect to the given body in Rodrigues parameters
body	the body with which the constraint Jacobian will be calculated; if the body is not either the inner or outer link, the constraint Jacobian will be a zero matrix
index	the index of the constraint equation for which to calculate
Cq	a vector that contains the corresponding column of the constraint Jacobian on returnMethod for initializing all variables in the joint This method should be called at the beginning of all constructors of all derived classes.