Package org.robwork.sdurw

Class Kinematics

java.lang.Object

org.robwork.sdurw.Kinematics

public class Kinematics
extends java.lang.Object

Utility functions for the rw::kinematics module.

Constructor Summary

Constructors

Constructor	Description
Kinematics(long cPtr, boolean cMemoryOwn)

Method Summary

Modifier and Type	Method	Description
static MapStringFrame	buildFrameMap(Frame root, State state)	A map linking frame names to frames. The map contains an entry for every frame below root in the tree with structure described by state.
static FrameVector	childToParentChain(Frame child, Frame parent, State state)	The chain of frames connecting child to parent. child is included in the chain, but parent is not included.
void	delete()
static FrameVector	findAllFrames(Frame root)	All frames reachable from root for a tree structure. This is a tremendously useful utility.
static FrameVector	findAllFrames(Frame root, State state)	All frames reachable from root for a tree structure of state. This is a tremendously useful utility.
static Transform3Dd	frameTframe(Frame from, Frame to, State state)	The transform of frame to relative to frame from. FrameTframe() is related to WorldTframe() as follows: frameTframe(from, to, state) == inverse(worldTframe(from, state)) * worldTframe(to, state);
static long	getCPtr(Kinematics obj)
static VectorVectorFrame	getStaticFrameGroups(Frame root, State state)	Get static frame groups. A static frame group consist of frames that are fixed with respect to the other frames in the group.
static void	gripFrame(Frame item, Frame gripper, State state)	Grip item with gripper thereby modifying state. item must be a DAF.
static void	gripFrame(MovableFrame item, Frame gripper, State state)	Grip item with gripper thereby modifying state. item must be a DAF.
static boolean	isDAF(Frame frame)	True if frame is a DAF and false otherwise.
static boolean	isFixedFrame(Frame frame)	Check if frame is fixed.
static FrameVector	parentToChildChain(Frame parent, Frame child, State state)	The chain of frames connecting parent to child. parent is included in the list, but child is excluded.
static FrameVector	reverseChildToParentChain(Frame child, Frame parent, State state)	Like ChildToParentChain() except that the frames are returned in the reverse order.
static Frame	worldFrame(Frame frame, State state)	Find the world frame of the workcell by traversing the path from frame to the root of the tree. The state state is needed to retrieve the parent frames, but the world frame returned is the same for any (valid) state.
static Transform3Dd	worldTframe(Frame to, State state)	The transform of frame in relative to the world frame. If to=NULL the method returns a 4 \times 4 identify matrix

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Kinematics

public Kinematics(long cPtr,
                  boolean cMemoryOwn)

Method Detail

getCPtr

public static long getCPtr(Kinematics obj)

delete

public void delete()

worldTframe

public static Transform3Dd worldTframe(Frame to,
                                       State state)

The transform of frame in relative to the world frame.

If to=NULL the method returns a 4 \times 4 identify matrix

Parameters:

to - [in] The transform for which to find the world frame.

state - [in] The state of the kinematics tree.

Returns:

The transform of the frame relative to the world frame.

frameTframe

public static Transform3Dd frameTframe(Frame from,
                                       Frame to,
                                       State state)

The transform of frame to relative to frame from.

FrameTframe() is related to WorldTframe() as follows:
frameTframe(from, to, state) == inverse(worldTframe(from, state)) * worldTframe(to, state);

Parameters:

from - [in] The start frame.

to - [in] The end frame.

state - [in] The state of the kinematics tree.

Returns:

The transform from the start frame to the end frame.

findAllFrames

public static FrameVector findAllFrames(Frame root,
                                        State state)

All frames reachable from root for a tree structure of
state.

This is a tremendously useful utility. An alternative would be to have an
iterator interface for trees represented by work cell states.

We give no guarantee on the ordering of the frames.

Parameters:

root - [in] The root node from where the frame search is started.

state - [in] The structure of the tree.

Returns:

All reachable frames.

findAllFrames

public static FrameVector findAllFrames(Frame root)

All frames reachable from root for a tree structure.

This is a tremendously useful utility. An alternative would be to have an
iterator interface for trees represented by work cell states.

We give no guarantee on the ordering of the frames.

DAF are not included.

Parameters:

root - [in] The root node from where the frame search is started.

Returns:

All reachable frames.

worldFrame

public static Frame worldFrame(Frame frame,
                               State state)

Find the world frame of the workcell by traversing the path
from frame to the root of the tree.

The state state is needed to retrieve the parent frames, but the
world frame returned is the same for any (valid) state.

childToParentChain

public static FrameVector childToParentChain(Frame child,
                                             Frame parent,
                                             State state)

The chain of frames connecting child to parent.

child is included in the chain, but parent is not included. If
parent is NULL then the entire path from child to the world
frame is returned. If child as well as parent is NULL then the
empty chain is gracefully returned.

The state gives the connectedness of the tree.

If parent is not on the chain from child towards the root, then
an exception is thrown.

reverseChildToParentChain

public static FrameVector reverseChildToParentChain(Frame child,
                                                    Frame parent,
                                                    State state)

Like ChildToParentChain() except that the frames are returned
in the reverse order.

parentToChildChain

public static FrameVector parentToChildChain(Frame parent,
                                             Frame child,
                                             State state)

The chain of frames connecting parent to child.

parent is included in the list, but child is excluded. If
parent as well as child is NULL then the empty chain is returned.
Otherwise parent is included even if parent is NULL.

buildFrameMap

public static MapStringFrame buildFrameMap(Frame root,
                                           State state)

A map linking frame names to frames.

The map contains an entry for every frame below root in the tree with
structure described by state.

Parameters:

root - [in] Root of the kinematics tree to search.

state - [in] The kinematics tree structure.

isDAF

public static boolean isDAF(Frame frame)

True if frame is a DAF and false otherwise.

isFixedFrame

public static boolean isFixedFrame(Frame frame)

Check if frame is fixed.

Parameters:

frame - [in] the frame.

Returns:

true if fixed, false otherwise.

gripFrame

public static void gripFrame(Frame item,
                             Frame gripper,
                             State state)

Grip item with gripper thereby modifying state.

item must be a DAF.

Parameters:

item - [in] the frame to grip.

gripper - [in] the grasping frame.

state - [in/out] the state.
Note: An exception is thrown if item is not a DAF.
Note: See also gripFrame(MovableFrame*, Frame*, State&).

gripFrame

public static void gripFrame(MovableFrame item,
                             Frame gripper,
                             State state)

Grip item with gripper thereby modifying state.

item must be a DAF.

Parameters:

item - [in] the frame to grip.

gripper - [in] the grasping frame.

state - [in/out] the state.
Note: An exception is thrown if item is not a DAF.
Note: See also gripFrame(Frame*, Frame*, State&).

getStaticFrameGroups

public static VectorVectorFrame getStaticFrameGroups(Frame root,
                                                     State state)

Get static frame groups.

A static frame group consist of frames that are fixed with respect to the other frames in
the group. A Dynamically Attachable Frame (DAF) or a MovableFrame will divide a static
group.

Parameters:

root - [in] the root frame of the tree to search.

state - [in] containing information about the current tree state and the Dynamically
Attachable Frames (DAF).

Returns:

vector with the frame groups.