Drivetrain Simulation with Ros2 Control

[nico-palmar]

We currently do not have a Gazebo simulation set up for our drivetrain.

As of right now (May 14), the ros2 control drivetrain code has not been merged into master but this is the current working branch: https://github.com/uwrobotics/uwrt_mars_rover/tree/user/andrew2002zhao/CAN-drivetrain-nico

The goal of this task would be to create a gazebo simulation which integrates the URDF that is in the branch above (ie. do not create a new URDF, just use the one there). The tasks are:

1. Spawn a drivetrain of our rover in gazebo (first try doing it by manually launching gazebo and spawning the drivetrain. The combine all of that into a launch file that can launch gazebo, spawn the drivetrain, and open rviz)
2. Integrate ros2 control into the gazebo simulation. Ros2 control has been tested on hardware but should be able to run in gazebo. You need to find out how to set up ros2 control to run in gazebo. In the end, you should be able to publish a cmd_vel command and see the drivetrain moving as expected in gazebo (see https://control.ros.org/master/doc/ros2_control_demos/example_2/doc/userdoc.html for details on running ros2 control). Note that you should not need to write anything new with ros2 control, it should be about figuring out how we can integrate ros2 control in gazebo so that our virtual actuators (ie. virtual motors and encoders) in gazebo can be moved properly with ros2 control.