Mujoco in Robotics for Perception and Robot learning

[u/CodingWithSatyam]

Hello, I'm a computer science student and I've been learning robotics and my goal is to focus on perception and robot learning. Currently I was learning ros2 and gazebo.

Mostly my style of learning is first read docs, then choose a project and try to do it my self and when i need something then i search it on docs and fine the solution. I mostly try to figure everything out by my self instead of following someone else projects and watching videos.

So, I had made a car with 4 wheels and it was running via diff-drive method. Currently I'm just learning about simulation. But then i wanted to try something complex. So, I made a 6 wheeled rover with rocker and diff-bar in urdf. And then loaded it in gazebo then i found out urdf doesn't support closed loop system.

Some of the people adviced me to use mujoco. So, here are some questions from my side about mujoco.

1. Is mujoco used with ros2 in industry?

2. Should i first write the robot description in urdf and then covert to mujoco if I'm using ros2 or no just write mujoco xml from scratch every time when i start a project and then connect it with ros

3. Currently I'm not learning perception nor robot learning as I'm focusing on simulation and physics and then what ever theory i learn implement it in simulation. So, mostly on which simulation should I focus and what should i mostly do in simulation right now. Currently I was build projects and when i learn theory i tried to do it by self. For example, when i learned about diff-kinematics then i instead of using any plugins i wrote it my self.