closed loop crash or not accurate when simulation.

[WeisonWEileen]

Intro

Hi!

I am a undergrad student at sustech, I use MuJoCo for my research on sim2sim.

My setup

ubuntu22.04 mujoco 3.2.3

What's happening? What did you expect?

I use equality/connect to implement closed loop robot. However, it crash when moving. I am sure my relative coordinate is accurate because I get it from solidworks. I expect the two hole site of the two link are aligned to each other.

https://github.com/user-attachments/assets/e9734706-b7ad-432b-ab8d-09ca11ccebc6

Steps for reproduction

sw file too big to reproduce

Minimal model for reproduction

Code required for reproduction

<equality>
    <connect name="connect_l" active="true" body1="calf_l_Link" body2="shank_l_Link"
        anchor="0.56 0 0.00885" />

    <connect name="connect_r" active="true" body1="calf_r_Link" body2="shank_r_Link"
        anchor="0.56 0 0.00885" />
</equality>

Confirmations

• [X] I searched the latest documentation thoroughly before posting.
• [X] I searched previous Issues and Discussions, I am certain this has not been raised before.

[yuvaltassa]

1. The video looks fine, where is the crash?
2. Your model is not loadable without the assets, so we can't reproduce.