Suggesting new features: Adhesion actuator and multiple robot support

[Bigenlight]

Hello! Thanks for making the repo @sangteak601!
I'm relatively new to robotics and recently started working with Mujoco. And this repo really help for my project! I actually succeed to implement my manipulator and do some simple pick & place demo task.

I have two suggestions for potential features that could further enhance this project:

1. Adhesion support
   In my knowledge, adhesion actuator(https://mujoco.readthedocs.io/en/stable/XMLreference.html#actuator-adhesion) are not supported right now. But since some gripper needs this feature, I was wondering if there is any plan for that.

2. Multiple robot support
   I am actually spawning two robot in Mujoco with this repo by making a 12dof(6dof + 6dof) robot :D. But the code became really inconvenient to maintain. Is there any plan for that also?

I'd love to hear your thoughts or advice on these ideas. If you feel these enhancements are worthwhile, I'm willing to contribute and possibly start working on a pull request myself, depending on my progress.

Thanks again for your hard work and openness to suggestions!

[sangteak601]

Hi @Bigenlight, thank you for the suggestions. I don't have any plans for either of them at the moment, but you are more than welcome to open a PR.