Drake
PositionKinematicsCache< T > Class Template Reference

This class is one of the cache entries in MultibodyTreeContext. More...

#include <drake/multibody/multibody_tree/position_kinematics_cache.h>

Public Member Functions

 PositionKinematicsCache (const MultibodyTreeTopology &topology)
 Constructs a position kinematics cache entry for the given MultibodyTreeTopology. More...
 
const Isometry3< T > & get_X_WB (BodyNodeIndex body_node_index) const
 Returns a constant reference to the pose X_WB of the body B (associated with node body_node_index) as measured and expressed in the world frame W. More...
 
Isometry3< T > & get_mutable_X_WB (BodyNodeIndex body_node_index)
 See documentation on the const version get_X_WB() for details. More...
 
const Isometry3< T > & get_X_PB (BodyNodeIndex body_node_id) const
 Returns a const reference to the pose X_PB of the body frame B as measured and expressed in its parent body frame P. More...
 
Isometry3< T > & get_mutable_X_PB (BodyNodeIndex body_node_id)
 See documentation on the const version get_X_PB() for details. More...
 
const Isometry3< T > & get_X_FM (BodyNodeIndex body_node_index) const
 For the mobilizer associated with the body node indexed by body_node_index, this method returns a const reference to the pose X_FM of the outboard frame M as measured and expressed in the inboard frame F. More...
 
Isometry3< T > & get_mutable_X_FM (BodyNodeIndex body_node_index)
 See documentation on the const version get_X_FM() for details. More...
 
Implements CopyConstructible, CopyAssignable, MoveConstructible, MoveAssignable
 PositionKinematicsCache (const PositionKinematicsCache &)=default
 
PositionKinematicsCacheoperator= (const PositionKinematicsCache &)=default
 
 PositionKinematicsCache (PositionKinematicsCache &&)=default
 
PositionKinematicsCacheoperator= (PositionKinematicsCache &&)=default
 

Detailed Description

template<typename T>
class drake::multibody::PositionKinematicsCache< T >

This class is one of the cache entries in MultibodyTreeContext.

It holds the kinematics results of computations that only depend on the generalized positions of the system. Kinematics results include:

  • Body frame B poses X_WB measured and expressed in the world frame W.
  • Pose X_FM of a mobilizer's outboard frame M measured and expressed in the inboard frame F.
  • Mobilizer's matrices H_FM (with F and M defined above) that map the mobilizer's generalized velocities v to cross-joint spatial velocities V_FM = H_FM * v.
Template Parameters
TThe mathematical type of the context, which must be a valid Eigen scalar.

Instantiated templates for the following kinds of T's are provided:

  • double
  • AutoDiffXd

They are already available to link against in the containing library.

Constructor & Destructor Documentation

PositionKinematicsCache ( const MultibodyTreeTopology topology)
inlineexplicit

Constructs a position kinematics cache entry for the given MultibodyTreeTopology.

Member Function Documentation

Isometry3<T>& get_mutable_X_FM ( BodyNodeIndex  body_node_index)
inline

See documentation on the const version get_X_FM() for details.

Here is the call graph for this function:

Here is the caller graph for this function:

Isometry3<T>& get_mutable_X_PB ( BodyNodeIndex  body_node_id)
inline

See documentation on the const version get_X_PB() for details.

Here is the caller graph for this function:

Isometry3<T>& get_mutable_X_WB ( BodyNodeIndex  body_node_index)
inline

See documentation on the const version get_X_WB() for details.

Here is the caller graph for this function:

const Isometry3<T>& get_X_FM ( BodyNodeIndex  body_node_index) const
inline

For the mobilizer associated with the body node indexed by body_node_index, this method returns a const reference to the pose X_FM of the outboard frame M as measured and expressed in the inboard frame F.

Parameters
[in]body_node_indexThe unique index for the computational BodyNode object associated with the mobilizer of interest.
Returns
A const reference to the pose X_FM of the outboard frame M as measured and expressed in the inboard frame F.

Here is the caller graph for this function:

const Isometry3<T>& get_X_PB ( BodyNodeIndex  body_node_id) const
inline

Returns a const reference to the pose X_PB of the body frame B as measured and expressed in its parent body frame P.

Parameters
[in]body_node_idThe unique identifier for the computational BodyNode object associated with body B.
Returns
X_PB a const reference to the pose of the the body frame B measured and expressed in the parent body frame P.

Here is the caller graph for this function:

const Isometry3<T>& get_X_WB ( BodyNodeIndex  body_node_index) const
inline

Returns a constant reference to the pose X_WB of the body B (associated with node body_node_index) as measured and expressed in the world frame W.

Parameters
[in]body_node_indexThe unique index for the computational BodyNode object associated with body B.
Returns
X_WB the pose of the the body frame B measured and expressed in the world frame W.

Here is the caller graph for this function:

PositionKinematicsCache& operator= ( const PositionKinematicsCache< T > &  )
default
PositionKinematicsCache& operator= ( PositionKinematicsCache< T > &&  )
default

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