Physsim::RigidBody

Physsim::RigidBody Class Reference

Represents a single rigid body. More...

#include <RigidBody.h>

Inheritance diagram for Physsim::RigidBody:

Physsim::DynamicBody Physsim::Visualizable Physsim::Base List of all members.

Public Member Functions

 RigidBody ()
 Default constructor.
virtual void load_state (BaseConstPtr clone, bimap< BasePtr, BasePtr > *correspondence=NULL)
 Loads the state of this body from another RigidBody object.
virtual bool is_struct_identical (BaseConstPtr object) const
 Verifies that two object structures are identical.
virtual void save_state (BasePtr object, bimap< BasePtr, BasePtr > *correspondence=NULL) const
 Saves the state of this body to another RigidBody object with the same structure.
virtual void clone (BasePtr &cloned, bimap< BasePtr, BasePtr > *obj_map=NULL) const
 Clones this body.
void set_avel (const Vector3 &avel, bool update_angular_momentum=false)
 Sets the angular velocity, optionally updating the angular momentum.
void set_qvel (const Quat &qd, bool update_angular_momentum=false)
 Sets the differential quaternion of this body.
void set_lvel (const Vector3 &lvel, bool update_linear_momentum=false)
 Sets the linear velocity of this body.
virtual VectorN get_state_deriv ()
 Gets the derivative of the state.
virtual void set_state (const VectorN &state)
 Sets the current state.
virtual VectorN get_state ()
 Gets the current state.
void add_force (const Vector3 &force)
 Adds a force to the center-of-mass of this link.
void add_torque (const Vector3 &torque)
 Adds a torque to the center-of-mass of this body.
void set_transform (const Matrix4 &transform)
 Sets the current 4x4 homogeneous transformation for this rigid body.
void set_transform (const Quat &q, const Vector3 &x)
 Sets the current 4x4 homogeneous transformation for this body using quaternion and vector position.
void set_inertia (const Matrix3 &m)
 Sets the inertia tensor for this body.
void set_enabled (bool flag)
 Sets the body to enabled / disabled.
void set_orientation (const Quat &q)
 Sets the orientation for this rigid body.
void set_position (const Vector3 &pos)
 Sets the position for this rigid body.
void remove_collision_geometry (CollisionGeometryPtr g)
 Removes the specified geometry from the rigid body.
void add_force (const Vector3 &f, const Vector3 &p)
 Adds a force at a particular point on the body.
void apply_impulse (const Vector3 &j, const Vector3 &p)
 Applies a linear impulse to this link at the specified point.
void apply_impulse (const Vector3 &j, const Vector3 &k, const Vector3 &p)
 Applies linear and angular impulses to this link at the specified point.
void set_mass (Real mass)
 Sets the mass of this body.
Matrix3 det_collision_matrix (const Matrix3 &contact_frame_transpose, const Vector3 &contact_point)
 Computes the collision matrix K (as described in [Mirtich, 1996], p. 61, for this body only.
virtual void transform (const Matrix4 &transform)
 Transforms the dynamic body by the given transform.
virtual void calc_fwd_dyn ()
 Computes the forward dynamics for this body.
std::list< CollisionGeometryPtr > get_all_collision_geometries () const
 Gets all collision geometries of this rigid body (including all descendants of collision geometries).
void set_linear_momentum (const Vector3 &P, bool update_velocity=false)
 Sets the linear momentum, optionally updating the linear velocity.
void set_angular_momentum (const Vector3 &L, bool update_velocity=false)
 Sets the angular momentum, optionally updating the angular velocity.
virtual void set_visualization_data (SoNode *vdata)
 Sets the visualization data from a node.
virtual void load_from_xml (XMLTreeConstPtr node, std::map< std::string, BasePtr > &id_map)
 Implements Base::load_from_xml().
virtual void save_to_xml (XMLTreePtr node, std::list< BaseConstPtr > &shared_objects) const
 Implements Base::save_to_xml().
Real calc_point_accel (const Vector3 &point, const Vector3 &dir)
 Calculates the acceleration at a point (typically somewhere on this body) along the desired direction.
Real calc_point_vel (const Vector3 &point, const Vector3 &dir) const
 Calculates the velocity of a point on this rigid body in a given direction.
virtual void output_object_state (std::ostream &out) const
 Outputs the object state to the specified stream.
bool remove_child_link (RigidBodyConstPtr link)
 Removes the specified child link from this link.
Vector3 get_inner_joint_to_com_vector_global () const
 Gets the vector that points from the inboard joint on this link to the center of mass on the link.
void set_inner_joint_to_com_vector_link (const Vector3 &v)
 Sets the vector that points from the inboard joint on this link to the center of mass on the link.
void set_inner_joint_to_com_vector_global (const Vector3 &v)
 Sets the vector that points from the inboard joint on this link to the center of mass on the link.
const Vector3 & get_com_to_outer_joint_vector_link (RigidBodyConstPtr child) const
 Gets the vector that points from the center of mass of this link to the inboard joint of the specified child link.
Vector3 get_com_to_outer_joint_vector_global (RigidBodyConstPtr child) const
 Gets the vector that points from the center of mass of this link to the inboard joint of the i'th child link.
void add_child_link_global (RigidBodyPtr child, const Vector3 &v)
 Adds a child link to the list of children of this link.
bool is_child_link (RigidBodyConstPtr query) const
 Determines whether the given link is a child link of this.
void reset_spatial_transforms ()
 Resets all spatial computations.
const SMatrix6 & get_spatial_transform_forward ()
 Returns the spatial transform from this link's parent to this link.
const SMatrix6 & get_spatial_transform_backward ()
 Returns the spatial transform from this link to this link's parent.
const SMatrix6 & get_spatial_transform_link_to_global ()
 Returns the spatial transform from this link to the global coordinate system.
const SMatrix6 & get_spatial_transform_global_to_link ()
 Returns the spatial transform from the global coordinates system to this link.
SVector6 get_spatial_accel (ReferenceFrameType rftype)
 Gets the spatial acceleration for this link.
void set_spatial_accel (const SVector6 &a, ReferenceFrameType rftype)
 Sets the spatial acceleration.
SVector6 get_spatial_velocity (ReferenceFrameType rftype)
 Gets the spatial velocity for this link.
void set_spatial_velocity (const SVector6 &v, ReferenceFrameType rftype)
 Sets the spatial velocity.
std::list< RigidBodyPtr > get_child_links () const
 Gets a list of child links.
void add_child_link_link (RigidBodyPtr l, const Vector3 &com_to_child_inner_joint_vec_link)
 Adds a child link to the list of children of this link.
void set_inner_joint (JointPtr j)
 Sets the inner joint for this link.
void set_parent_link (RigidBodyPtr l)
 Sets the parent of this link; set to NULL to indicate no parent.
RigidBodyPtr get_this ()
 Gets the shared pointer for this.
RigidBodyConstPtr get_this () const
 Gets the shared const pointer for this.
const Matrix4 & get_transform () const
 Gets the current transform of this body.
Real get_mass () const
 Gets the mass of this body.
Real get_mass_inv () const
 Gets the inverse mass of this body.
const Matrix3 & get_inertia () const
 Gets the 3x3 inertia tensor of this body.
const Matrix3 & get_inertia_inv () const
 Gets the inverse of the 3x3 inertia tensor of this body.
const Vector3 & get_position () const
 Gets the position of this body.
const Quat & get_orientation () const
 Gets the quaternion orientation of this body.
const Vector3 & get_lvel () const
 Gets the linear velocity of this body.
const Vector3 & get_avel () const
 Gets the angular velocity of this body.
const Quat & get_qvel () const
 Gets the differential quaternion of this body.
const Vector3 & get_laccel ()
 Gets the linear acceleration of this body.
const Vector3 & get_aaccel ()
 Gets the angular acceleration of this body.
void set_aaccel (const Vector3 &a)
 Sets the angular acceleration of this link.
void set_laccel (const Vector3 &a)
 Sets the angular acceleration of this link.
const SMatrix6 & get_spatial_iso_inertia_link ()
 Gets the spatial isolated inertia of this link, in link coordinates.
void reset_accumulators ()
 Resets the force and torque accumulators of this body.
const Vector3 & sum_forces () const
 Gets the sum of forces on this body.
const Vector3 & sum_torques () const
 Gets the sum of torques on this body.
bool is_enabled () const
 Gets whether this body is enabled.
unsigned num_collision_geometries () const
 Gets the number of collision geometries for this body.
void add_collision_geometry (CollisionGeometryPtr g)
 Adds a collision geometry for this body.
void remove_collision_geometry (unsigned i)
 Removes a collision geometry of this body.
void clear_collision_geometries ()
 Clears the set of collision geometries.
CollisionGeometryPtr get_collision_geometry (unsigned i)
 Gets the specified collision geometry of this body.
const std::vector< CollisionGeometryPtr > & get_collision_geometries () const
 Gets all collision geometries of this body.
const Vector3 & get_linear_momentum () const
 Gets the linear momentum of this body.
void update_linear_momentum ()
 Updates the linear momentum of this body using the linear velocity.
const Vector3 & get_angular_momentum () const
 Gets the angular momentum of this body.
void update_angular_momentum ()
 Updates the angular momentum of this body using the angular velocity.
boost::weak_ptr< ArticulatedBody > get_articulated_body () const
 Gets the articulated body corresponding to this body.
void set_articulated_body (boost::weak_ptr< ArticulatedBody > body)
 Sets the articulated body corresponding to this body.
const std::map< RigidBodyPtr,
Vector3 > & 		get_child_link_map () const
 Returns the map of child links to their corresponding vector from this link's com to the child link's com, in this link's frame.
bool is_base () const
 Determines whether this link is the base (faster than get_parent_link() == NULL).
const Vector3 & get_inner_joint_to_com_vector_link () const
 Gets the vector that points from the inboard joint on this link to the center of mass on the link.
boost::weak_ptr< Joint > get_inner_joint () const
 Gets the inner joint for this link.
boost::weak_ptr< RigidBody > get_parent_link () const
 Gets the parent link of this link; returns NULL if there is no parent.
unsigned num_child_links () const
 Gets the number of child links of this link.
bool is_end_effector () const
 Gets whether this body is an end-effector (i.e., the number of child links is zero) in an articulated body.
void set_child_link_link (RigidBodyPtr child, const Vector3 &com_to_inner_joint_vec_link)
 Adds a child link to the list of children of this link.
void set_child_link_global (RigidBodyPtr child, const Vector3 &com_to_inner_joint_vec_global)
 Sets a child link to the list of children of this link.
void clear_child_links ()
 Removes all child links from this link.
unsigned get_index ()
 Gets the link index (returns std::numeric_limits<unsigned>::max() if not set).
void set_index (unsigned index)
 Sets the link index.

Static Public Member Functions

static Real calc_sep_accel (RigidBody &rb1, RigidBody &rb2, const Vector3 &point, const Vector3 &dir, const Vector3 &dir_dot)
 Calculates the separation acceleration of a common point on two bodies along the desired direction.

Detailed Description

Represents a single rigid body.

Contains information needed to represent a rigid body, including position and velocity (both linear and angular), mass, center of mass, inertia matrix, collision data, and visualization data. This class is used for both non-articulated and articulated rigid bodies, though not all member data may be used in the latter.

Todo:
implement rest matrix

Constructor & Destructor Documentation

RigidBody::RigidBody (  ) 

Default constructor.

Constructs a rigid body with zero mass, zero inertia tensor, and center of mass at [0,0,0] with position at [0,0,0], identity orientation, and zero linear and angular velocity. Body is enabled by default.

Member Function Documentation

void RigidBody::load_state ( BaseConstPtr  object,
bimap< BasePtr, BasePtr > *  correspondence = NULL 
) [virtual]

Loads the state of this body from another RigidBody object.

The structure of the two rigid bodies must be identical -- specifically, both must have the same number of collision geometries (each of which has identical structure as well) and both must have one/no pointer to an articulated body.

Reimplemented from Physsim::Visualizable.

void RigidBody::save_state ( BasePtr  object,
bimap< BasePtr, BasePtr > *  correspondence = NULL 
) const [virtual]

Saves the state of this body to another RigidBody object with the same structure.

The structure of the two rigid bodies must be identical -- specifically, both must have the same number of collision geometries (each of which has identical structure as well) and both must have one/no pointer to an articulated body.

Reimplemented from Physsim::Visualizable.

void RigidBody::clone ( BasePtr &  cloned,
bimap< BasePtr, BasePtr > *  object_map = NULL 
) const [virtual]

Clones this body.

Performs a shallow copy of the underlying collision geometry and visualization data.

Reimplemented from Physsim::Visualizable.

void RigidBody::set_qvel ( const Quat &  qd,
bool  update_ang_momentum = false 
)

Sets the differential quaternion of this body.

Precondition:
the orientation of the body must be set first; otherwise, the result is undefined

VectorN RigidBody::get_state_deriv (  )  [virtual]

Gets the derivative of the state.

If the body is disabled, the derivative is a zero vector.

Returns:
a 13-dimensional vector, partitioned as follows:
Parameters:
return a 13-dimensional vector partitioned as follows:
0-2 linear velocity
3-6 angular velocity (quaternion form)
7-9 cumulative force vector <br / 10-12 cumulative torque vector

Implements Physsim::DynamicBody.

void RigidBody::set_state ( const VectorN &  state  )  [virtual]

Sets the current state.

Parameters:
state a 13-dimensional vector, partitioned as follows:
0-2 position of center of mass
3-6 quaternion orientation of body
7-9 linear momentum of body
10-12 angular momentum of body

Implements Physsim::DynamicBody.

VectorN RigidBody::get_state (  )  [virtual]

Gets the current state.

Returns:
a 13-dimensional vector, partitioned as follows:
0-2 position of center of mass
3-6 quaternion orientation of body
7-9 linear momentum of body
10-12 angular momentum of body

Implements Physsim::DynamicBody.

void RigidBody::add_force ( const Vector3 &  force  ) 

Adds a force to the center-of-mass of this link.

The frame of the applied force is centered at the center-of-mass of the body and is aligned with the global frame.

void RigidBody::add_torque ( const Vector3 &  torque  ) 

Adds a torque to the center-of-mass of this body.

The frame of the applied torque is centered at the center-of-mass of the body and is aligned with the global frame.

void RigidBody::set_transform ( const Matrix4 &  T  ) 

Sets the current 4x4 homogeneous transformation for this rigid body.

Also updates the transforms for associated visualization and collision data.

void RigidBody::set_enabled ( bool  flag  ) 

Sets the body to enabled / disabled.

If the body is disabled, the linear and angular velocity are set to zero, and the body will not be updated if it is attempted to integrate its equations of motion.

void RigidBody::set_orientation ( const Quat &  q  ) 

Sets the orientation for this rigid body.

Also updates the transforms for associated visualization and collision data.

void RigidBody::set_position ( const Vector3 &  v  ) 

Sets the position for this rigid body.

Also updates the transforms for associated visualization and collision data.

void RigidBody::add_force ( const Vector3 &  f,
const Vector3 &  p 
)

Adds a force at a particular point on the body.

The frame of the applied force is centered at p and is aligned with the global frame.

Parameters:
f the force
p the position on the body in world coordinates (i.e., not relative to the center-of-mass)

void RigidBody::apply_impulse ( const Vector3 &  j,
const Vector3 &  p 
)

Applies a linear impulse to this link at the specified point.

Parameters:
j the linear component of the impulse
k the angular component of the impulse
p the point (global frame) at which the impulse is to be applied

void RigidBody::apply_impulse ( const Vector3 &  j,
const Vector3 &  k,
const Vector3 &  p 
)

Applies linear and angular impulses to this link at the specified point.

Parameters:
j the linear component of the impulse
k the angular component of the impulse
p the point (global frame) at which the impulse is to be applied

Matrix3 RigidBody::det_collision_matrix ( const Matrix3 &  contact_frame_transpose,
const Vector3 &  contact_point 
)

Computes the collision matrix K (as described in [Mirtich, 1996], p. 61, for this body only.

Parameters:
contact_frame_transpose the transpose of the contact frame
contact_point the point of contact

Real RigidBody::calc_point_accel ( const Vector3 &  point,
const Vector3 &  dir 
)

Calculates the acceleration at a point (typically somewhere on this body) along the desired direction.

Parameters:
point the point in the global frame
dir the direction in which acceleration is to be computed
dir_dot the derivative of the direction in which acceleration is to be computed
Returns:
the acceleration along dir
Note:
this may modify the body, because it will trigger forward dynamics via calls to get_laccel() and get_raccel().

void RigidBody::output_object_state ( std::ostream &  out  )  const [virtual]

Outputs the object state to the specified stream.

This method outputs all of the low-level details to the stream; if serialization is desired, use save_to_xml() instead.

See also:
save_to_xml()

Reimplemented from Physsim::Base.

bool RigidBody::remove_child_link ( RigidBodyConstPtr  child  ) 

Removes the specified child link from this link.

Also removes the associated _com_ to outboard vector. Returns true if the link was found.

Vector3 RigidBody::get_inner_joint_to_com_vector_global (  )  const

Gets the vector that points from the inboard joint on this link to the center of mass on the link.

Gets the vector from the inboard joint to the center-of-mass in world coordinates (i.e., varies with link transform).

See also:
getinner_joint_to_com_vector_link()

void RigidBody::set_inner_joint_to_com_vector_link ( const Vector3 &  v  ) 

Sets the vector that points from the inboard joint on this link to the center of mass on the link.

Sets the vector from the inboard joint to the center-of-mass in link coordinates of the link (i.e., invariant to link orientation).

See also:
set_inner_joint_to_com_vector_global()

void RigidBody::set_inner_joint_to_com_vector_global ( const Vector3 &  v  ) 

Sets the vector that points from the inboard joint on this link to the center of mass on the link.

Sets the vector from the inboard joint to the center-of-mass in world coordinates (i.e., varies with link transform).

Parameters:
v the global position of the inboard joint
See also:
getinner_joint_to_com_vectorLocal()

const Vector3 & RigidBody::get_com_to_outer_joint_vector_link ( RigidBodyConstPtr  child  )  const

Gets the vector that points from the center of mass of this link to the inboard joint of the specified child link.

Gets the vector from the center-of-mass of the link to the inboard joint of the specified child link in link coordinates (i.e., invariant to link orientation).

Returns:
the 3D vector or the zero vector (as well as failing an assertion) if the specified child does not exist
See also:
get_com_to_outboard_joint_vector_global()

Vector3 RigidBody::get_com_to_outer_joint_vector_global ( RigidBodyConstPtr  link  )  const

Gets the vector that points from the center of mass of this link to the inboard joint of the i'th child link.

Gets the vector from the center-of-mass of the link to the inboard joint of the i'th child link in global coordinates (i.e., varies with link orientation).

Returns:
the 3D vector, or the zero vector if the child link does not exist
See also:
get_com_to_outboard_joint_vector_link()

void RigidBody::add_child_link_global ( RigidBodyPtr  child,
const Vector3 &  com_to_inner_joint_vec_global 
)

Adds a child link to the list of children of this link.

Parameters:
child the child link; if child is already a child link of this link the new com_to_inner_joint_vec_global will be used
com_to_inner_joint_vec_global a vector from the center-of-mass of this link to the inner joint of the child link (i.e., the outer joint of this link) in the global frame
Note:
automatically makes child point to this as its parent

this method is synonymous with set_child_link_global()

See also:
set_child_link_global()

void RigidBody::reset_spatial_transforms (  ) 

Resets all spatial computations.

"Forward", "backward", link-to-global and global-to-link transforms are all reset.

const SMatrix6 & RigidBody::get_spatial_transform_forward (  ) 

Returns the spatial transform from this link's parent to this link.

Note:
the spatial transform will be computed if necessary

const SMatrix6 & RigidBody::get_spatial_transform_backward (  ) 

Returns the spatial transform from this link to this link's parent.

Note:
the spatial transform will be computed if necessary

const SMatrix6 & RigidBody::get_spatial_transform_link_to_global (  ) 

Returns the spatial transform from this link to the global coordinate system.

Note:
the spatial transform will be computed if necessary

const SMatrix6 & RigidBody::get_spatial_transform_global_to_link (  ) 

Returns the spatial transform from the global coordinates system to this link.

Note:
the spatial transform will be computed if necessary

void RigidBody::add_child_link_link ( RigidBodyPtr  child,
const Vector3 &  com_to_child_inner_joint_vec_link 
)

Adds a child link to the list of children of this link.

Parameters:
child the child link; if child is already a child link of this link the new com_to_inner_joint_vec_link will be used
com_to_inner_joint_vec_link a vector from the center-of-mass of this link to the inner joint of the child link (i.e., the outer joint of this link) in this link's frame
Note:
automatically makes child point to this as its parent

this method is synonymous with set_child_link_link()

See also:
set_child_link_link()

void RigidBody::set_inner_joint ( JointPtr  j  ) 

Sets the inner joint for this link.

Also attempts to update articulated body pointers as well as parent IDs, if possible...

void RigidBody::set_parent_link ( RigidBodyPtr  l  ) 

Sets the parent of this link; set to NULL to indicate no parent.

Also attempts to update articulated body pointers as well as parent IDs, if possible...

const Vector3& Physsim::RigidBody::get_laccel (  )  [inline]

Gets the linear acceleration of this body.

Note:
It is the user's responsibility to call calc_fwd_dyn() before calling this method (if necessary)!

const Vector3& Physsim::RigidBody::get_aaccel (  )  [inline]

Gets the angular acceleration of this body.

Note:
It is the user's responsibility to call calc_fwd_dyn() before calling this method (if necessary)!

const Vector3& Physsim::RigidBody::sum_forces (  )  const [inline]

Gets the sum of forces on this body.

The frame of the sum of forces is centered at the center-of-mass of the body and is aligned with the global frame.

const Vector3& Physsim::RigidBody::sum_torques (  )  const [inline]

Gets the sum of torques on this body.

The frame of the sum of torques is centered at the center-of-mass of the body and is aligned with the global frame.

boost::weak_ptr<ArticulatedBody> Physsim::RigidBody::get_articulated_body (  )  const [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

void Physsim::RigidBody::set_articulated_body ( boost::weak_ptr< ArticulatedBody >  body  )  [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

const Vector3& Physsim::RigidBody::get_inner_joint_to_com_vector_link (  )  const [inline]

Gets the vector that points from the inboard joint on this link to the center of mass on the link.

Gets the vector from the inboard joint to the center-of-mass in the link frame.

See also:
get_inner_joint_to_com_vector_global()

void Physsim::RigidBody::set_child_link_link ( RigidBodyPtr  child,
const Vector3 &  com_to_inner_joint_vec_link 
) [inline]

Adds a child link to the list of children of this link.

Parameters:
child the child link; if child is already a child link of this * link the new com_to_inner_joint_vec_link will be used
com_to_inner_joint_vec_link a vector from the center-of-mass of this link to the inner joint of the child link (i.e., the outer joint of this link) in this link's frame
Note:
this method is synonymous with set_child_link_link()

automatically makes child point to this as its parent

See also:
add_child_link_link()

void Physsim::RigidBody::set_child_link_global ( RigidBodyPtr  child,
const Vector3 &  com_to_inner_joint_vec_global 
) [inline]

Sets a child link to the list of children of this link.

Parameters:
child the child link; if child is already a child link of this link the new com_to_inner_joint_vec_global will be used
com_to_inner_joint_vec_global a vector from the center-of-mass of this link to the inner joint of the child link (i.e., the outer joint of this link) in the global frame
Note:
this method is synonymous with add_child_link_global()

automatically makes child point to this as its parent

See also:
add_child_link_global()

void Physsim::RigidBody::set_index ( unsigned  index  )  [inline]

Sets the link index.

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

The documentation for this class was generated from the following files:
Generated on Wed Oct 24 14:54:23 2007 for Physsim by  doxygen 1.5.1