CMC failure, a cry for help.

Sietse Achterop · Post by **Sietse Achterop** » Mon Jan 01, 2024 5:41 am

It sounds a bit dramatic, but I really am stuck with my CMC project.
I created a few opensim-issues (see issue #3522) and asked on this forum,
but the problem still is not solved.
I created a model and trajectory as simple as possible that fails.
This is both on Windows and Linux.
The model consist of not much more than a Pinjoint and one Balljoint:

Test4.zip: (10.47 KiB) Downloaded 42 times

The trajectory is keeping the model mostly still, but after a few seconds it will start to behave very strange.

: Test4.png (194.66 KiB) Viewed 19019 times

: Run_away.png (44.85 KiB) Viewed 19019 times

Shouldn't we be able to explain why such a model is failing?
I think it is interesting to understand why CMC fails with such simple models.
Is it CMC or is it me. Why doesn't the PD-control part kick in?
Can somebody please confirm that this model behaves as mentioned here?
Please help, Sietse

Mohammadreza Rezaie · Post by **Mohammadreza Rezaie** » Thu Jan 11, 2024 2:30 pm

Hi, you may want to try replacing the BallJoint with CustomJoint.
https://github.com/opensim-org/opensim- ... 1879337616

Sietse Achterop · Post by **Sietse Achterop** » Fri Jan 12, 2024 4:01 am

Yes, thanks alot for that!
(sorry for the late response)

CMC failure, a cry for help.

CMC failure, a cry for help.

Re: CMC failure, a cry for help.

Re: CMC failure, a cry for help.