Create ROS support for a non supported robot (e.g. GoPiGo3)

edit

You need to expose the interface to the robot to the ROS.

I.e., in the end, you need to write a driver/wrapper that exposes all of your robot hardware (sensors, drives, ...) to ROS, and that can read ROS message to command your robot hardware.

For a lot of sensors, there are drivers already available.

What typically is pretty hardware specific is the kinematics / base. As an interface, you typically have, as output, a nav_msgs/Odometry providing current speed of the base as well as broadcasting the integrated odometry using a tf::Broadcaster; as input, you typically have a geometry_msgs/Twist which is the commanded speed for your robot.

For a more detailed answer, we'd need more details on your question. Please post a new one for more specific questions.

Also, a quick google search lead to: https://forum.dexterindustries.com/t/... , and then to github.com/ros-gopigo. Did you check this out?