Collision size parameter may be wrong in ur10e

[midiexiangxxx]

Short report

Dear MuJoCo Developers.
I hope this message finds you well. I'm writing to respectfully report an issue I've encountered with the ur10e.xml model in MuJoCo Menagerie. It appears to have an incorrect collision size for the shoulder_link's default geom definition. This leads to an erroneous collision detection with the ground, generating large contact forces and causing instability in the simulation environment. Adjusting the size parameter of this geom resolves the issue. I'd like to provide a minimal example to reproduce the problem, and I would like to propose a Pull Request (PR) to fix this.

Minimal example

1. comment out <keyframe> (line 142-144) in ur10e.xml, and simply run mujoco's simulate, we can see that there is a contact collision between shoulder_link and the ground. This caused a very large force perpendicular to the ground, I'm guessing it's this anomalous force that's causing the instability of the little box.
2. Comment out line 81 or change the size to size="0.06 0.07" solves this problem.

This change might be helpul for issues like #154 #40 .

[midiexiangxxx]

A video to help show this problem in my own project:

Screencast.from.2025-07-10.22-37-02.webm