shady.common.multi.chain
Class StickBlock

java.lang.Object
  shady.common.multi.chain.Block
      shady.common.multi.chain.StickBlock

public class StickBlock
extends Block

Controller for a tower "stick"

The stick is composed of one MemberShadys (M[0]) and one segment (S[0]), all of length SL:

                             |                                
                             |                                
                             S0                                
                             |                                
                             |r                                
                             |                                
                             M0                                
                             |                                
                             |                                
                             |l                                
                                                             
 

Angles and lengths in the figure are not precise, but illustrate that, in nominal pose (DOF = 0.0), the shady is below holding the segment straight up.

Copyright (C) 2006 Marsette A. Vona, III

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

Author:

Carrick Detweiler

Field Summary

static double	CC The length of each shady.
private static java.lang.String	cvsid CVS id.
protected Point.OnSegment	eePoint The end-effector point, which is at 0.5 along the body segment of member 2.
static int	NUM_MEMBERS Number of member shadys in this stick block.
static int	NUM_SEGMENTS Number of segments in this stick block.
static double	SL The length of the muntin.
static double	THETA_MAX_ABS The absolute value of the maximum possible tilt angle.

Fields inherited from class shady.common.multi.chain.Block

dof, leftBarrel, locked, memberStartIndex, multiEnvironment, multiShady, next, numMembers, numSegments, previous, rightBarrel, segmentStartIndex, sentinel, transform

Constructor Summary

StickBlock(MultiShadyCommonAPI multiShady, MultiEnvironment multiEnvironment, Sentinel sentinel)
TBD

Method Summary

double	getEEOrientationOffset() Return the offset in radians of the EE frame orientation relative to the orientation of the Segment of the end-effector point.
Point.OnSegment	getEEPoint() Get the end-effector point.
protected void	initMembersAndSegments() Subclasses must implement this to set up the MemberShadys and environment segments.
protected void	recompute(vona.math.RigidTransform2D transform, double delta) Subclasses must implement this to compute the transform from the Block.previouss end frame to this block's end frame according to Block.dof, and possibly to update Block.leftBarrel and Block.rightBarrel from Block.dof.
protected boolean	recoverDOF() Try to figure out the current Block.dof from the state of the barrel angles in Block.multiShady.

Methods inherited from class shady.common.multi.chain.Block

getDOF, getNext, getPrevious, getTransform, getTransform, hasNext, hasPrevious, isLocked, isSentinel, lock, lock, recompute, reverseUpdate, reverseUpdateChain, setDOF, setNominal, tweakDOF, unlock, update, updateChain

Methods inherited from class java.lang.Object

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

Field Detail

cvsid

private static final java.lang.String cvsid

CVS id.

See Also:

Constant Field Values

NUM_MEMBERS

public static final int NUM_MEMBERS

Number of member shadys in this stick block.

See Also:

Constant Field Values

NUM_SEGMENTS

public static final int NUM_SEGMENTS

Number of segments in this stick block.

See Also:

Constant Field Values

CC

public static final double CC

The length of each shady.

See Also:

Constant Field Values

SL

public static final double SL

The length of the muntin.

See Also:

Constant Field Values

THETA_MAX_ABS

public static final double THETA_MAX_ABS

The absolute value of the maximum possible tilt angle.

See Also:

Constant Field Values

eePoint

protected Point.OnSegment eePoint

The end-effector point, which is at 0.5 along the body segment of member 2.

Constructor Detail

StickBlock

public StickBlock(MultiShadyCommonAPI multiShady,
                  MultiEnvironment multiEnvironment,
                  Sentinel sentinel)

TBD

Method Detail

initMembersAndSegments

protected void initMembersAndSegments()

Subclasses must implement this to set up the MemberShadys and environment segments.

Block.numMembers and Block.numSegments must be set, and the corresponding numbers of members and segments must be initialized (according to Block.dof, Block.leftBarrel, Block.rightBarrel, and Block.transform, which should all be consistent due to a prior call to Block.recompute()) and added to Block.multiShady and Block.multiEnvironment. Internal barrels must be closed to form the block topology, and barrels must be closed to connect to Block.previous iff it's not a Sentinel.

This implementation creates the stick block. All of the barrels are gripped normally on the segments (ie not inverted). Internally, the right grippers are connected to the beginning of the segments (0.0) and the left grippers are connected to the ends (1.0).

Specified by:

initMembersAndSegments in class Block

recompute

protected void recompute(vona.math.RigidTransform2D transform,
                         double delta)

Subclasses must implement this to compute the transform from the Block.previouss end frame to this block's end frame according to Block.dof, and possibly to update Block.leftBarrel and Block.rightBarrel from Block.dof.

This implementation makes use of geometry described in the header to compute the transform for a given delta which represents the theta of bending.

Specified by:

recompute in class Block

Parameters:

transform - the computed transform is to be written here, not null

delta - if non-zero then the DOF is incremented by this amount before computing the transform (the persistent Block.dof is not affected). This is used by ChainIK to compute columns of the chain Jacobian. The barrel angles are (allocated and) computed iff delta is 0.0. The caller must ensure that the incremented value will be in the range [-1.0,1.0].

recoverDOF

protected boolean recoverDOF()

Try to figure out the current Block.dof from the state of the barrel angles in Block.multiShady.

It can be assumed that the barrel angles were set as if by a call to Block.recompute(RigidTransform2D, double). If this does not appear to be the case then return false without modifying dof.

This impl recovers DOF as set by recompute(vona.math.RigidTransform2D, double).

Specified by:

recoverDOF in class Block

Returns:

true iff successful

getEEPoint

public Point.OnSegment getEEPoint()

Get the end-effector point.

Note that the point may either reference a standard Segment or the body segment of a member as returned by ShadyPose.getBodySegment(double).

This impl returns eePoint.

Specified by:

getEEPoint in class Block

Returns:

the end-effector point

getEEOrientationOffset

public double getEEOrientationOffset()

Return the offset in radians of the EE frame orientation relative to the orientation of the Segment of the end-effector point.

This impl returns -Math.PI/2.0.

Specified by:

getEEOrientationOffset in class Block

Returns:

the offset in radians of the EE frame orientation relative to the orientation of the Segment of the end-effector point