[ODE] Returning to a previous state?

Jun Li junjy at dcs.qmul.ac.uk
Fri Mar 3 01:11:09 MST 2006


Hi, Thanks.
But I think I've already subscribe it.

My mail box looks like:

"ODE digest: vol XX, Issue XX
ODE digest: vol XX, Issue XX
ODE digest: vol XX, Issue XX
ODE digest: vol XX, Issue XX
...."

What's wrong?

Jun.


ak wrote:

>hi.
>
>Am Donnerstag, den 02.03.2006, 21:45 +0000 schrieb Jun Li:
>  
>
>>I have encountered the same problem.
>>
>>As you mentioned, the current save-to-file scheme is not suitable for 
>>the application such as:
>>try to apply a torque/force to some link, observe it's effect to the 
>>system, according that effects
>>of every torque compute the correct value for the torque/force and then 
>>recover the system state
>>and apply the obtained torque/force(s).
>>
>>In the following, note those in capital, which is not mentioned in your 
>>mail.
>>
>>I used the same way as yours, that is, storing all the positions, 
>>rotations(quaternions), linear and
>>ANGULAR velocities, joint anchor points and AXES and reset them.
>>
>>Joint ANGLEs are computed from the axis of the joint and the 
>>orientations of the two bodies
>>attached.  It is set to zero every time you call dJointSetXXXX(), so you 
>>cannot explicitly reset
>>a joint angle. If you want keep track to the angle, you need to record 
>>them every time you store
>>and reset the system.
>>
>>One pitfall of this method I encountered is that: the ORDER of resetting 
>>those values is
>>important. As mentioned above, dJointSetXXXX remember the corrent bodies 
>>orientations
>>and affects the  following dJointGetAngle(). So when you reset the 
>>system, you must first
>>reset all bodies'  configuration(position, orientation, and l/a 
>>velocities), and then you can
>>reset the joint anchor point and axis. Otherwise, you shall failed to 
>>track the joint angles.
>>
>>BTW,
>>Why I can only receive the daily digest of this mail list? Who can tell 
>>me how to get fresh mails?
>>(Please send to my mailbox directly.)
>>    
>>
>this is the maillist-configuration, you choose it when you subscribe to
>this list.
>
>nothing more to say.
>
>cheers
>
>ak
>  
>



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