It looks like a couple of people tried helping you out on Gazebo Answers and the issue tracker.
I think that posting the question in more places may not be the best way for you to get the answers you need. Reading through the other posts, it looks like you managed to get a simplified example to reproduce the issue, but it’s not clear yet whether it’s a matter of fixing your configuration or if 's a bug in Gazebo that needs to be fixed.
I recommend you try to debug the issue a bit more in order to pin-point the problem. I tried running your model with Bullet (
gazebo -e bullet) and it also goes a bit crazy, but doesn’t explode the way it does with ODE. I also looked at your joints and I’m wondering if you don’t mean to use a
universal joint instead of the 2
revolutes with the same origin. I’d also try not to use
use_parent_model_frame since that’s mainly legacy behaviour.
Good luck debugging it