[ODE] Rolling ball bouncing problem

[Olivier Michel]

After repairing my mouse, I could also repair my code... I wasn't 
assigning a correct mass for the sphere... So now, everything runs fine 
with dContactApprox1. Many thanks!

-Olivier

Olivier Michel wrote:

> 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
>>>
>>> _______________________________________________
>>> ODE mailing list
>>> ODE@q12.org
>>> http://q12.org/mailman/listinfo/ode
>>>
>>>   
>>
>>
>> _______________________________________________
>> ODE mailing list
>> ODE@q12.org
>> http://q12.org/mailman/listinfo/ode
>>
>>  
>>
>

-- 
-Olivier Michel
http://www.cyberbotics.com