[ODE] Rolling ball bouncing problem

[Olivier Michel]

I tryed setting the dContactApprox1 (for pyramidal friction) in the 
appropriate contact joints but this didn't change anything to the 
behavior of my ball...

This seems to be a very simple problem, but it fails... Anyone succeeded 
with bouncing a rolling sphere against a box ?

I blew up my computer mouse to extract the ball and played a little bit 
with it, bumping it into the wall of my office. I could see that my 
rolling mouse ball, bounced almost exactly like if it was not rolling 
(i.e., sliding on ice). However, in my ODE simulation, this is not yet 
the case... It seems that the angular velocity is not changed after the 
collision, whereas I belive it should be drastically changed. Still 
trying desesperately to tune the parameters (mu, ball mass, etc.) and 
check my code and to fix my mouse...

-Olivier

skjold@cistron.nl wrote:

>Hi,
>
>I haven't tried any of this yet, but could it perhaps have anything to do with the problem described in the docs, at "11.13: My rolling bodies (e.g. wheels) sometimes get stuck between geoms"? If what you describe has the same cause, it might help to use the dContactApprox1 flag in the appropriate contact joints (if you weren't already doing that). 
>
>Hope that helps.
>
>
>  
>
>>Hi,
>>
>>It seems after many trials, that ODE has problems handling a rolling 
>>ball bouncing over a box.
>>I have set up a pool-like environment with a ball rolling over the 
>>ground nicely.
>>However, when the ball hits the surrounding wall, it doesn't bounce as 
>>expected. Rather, it follows the wall...
>>
>>This problem can be seen on the test_boxstack example. Drop some boxes, 
>>then drop some spheres, with some patience, you will see a sphere 
>>rolling towards a box, hit the box, follow the box edge until the box 
>>corner and even move around the box... which doesn't look natural at all...
>>
>>I tryed to make the static friction very low, then the bounce behavior 
>>is more natural, however, the ball doesn't roll, but it slides... Maybe 
>>the solution is a fine tunning the of the static / kinetic friction 
>>parameters...
>>
>>Any hint to work around this problem ?
>>
>>-Olivier
>>
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-- 
-Olivier Michel
http://www.cyberbotics.com