Closed Quirina300 closed 8 months ago
Hi @Quirina300 ,
Thanks for reporting this issue. I played around with the example and found that the problem is related to numerical inaccuracies. Specifically, pybullet's velocity controller cannot ensure that the target-velocity is reached within one time step. See https://pybullet.org/Bullet/phpBB3/viewtopic.php?t=12688 for a detailed discussion.
One solution to that is to increase the number of sub_steps performed in during one time step. The current setup in urdfenvs is num_sub_steps = 20
.
https://github.com/maxspahn/gym_envs_urdf/blob/57b82e7ead09941450f8b53200b6b1fd3c9811f7/urdfenvs/urdf_common/urdf_env.py#L85
When this value is increase to 200, or the time step dt=0.01
is decreased to dt=0.001
(the same effect), the problem is solved. However, it is currently not supported to change the value for num_sub_steps from the front-end. I will create a PR on that.
The mobile panda slowly collapses even when the actions and velocity are set to zero. The code we used to get this issue: