#Roboticists would like to create robots, simulate them, develop their software, then deploy on the hardware.

In hashtag#ROS 2 ecosystem, for simulation, we use hashtag#Gazebo. But you may ask, how to model the robot and import it in Gazebo?

🐢 For modelling the robot, we use URDF format. It’s kind of xml file that describe the links, joints, geometry, and collision elements of the robot.

🤷‍♂️ Should you create the URDF manually? Definitely no — doing that manually is not possible. So, what is the solution for creating URDFs and loading the robot in Gazebo? I have the answer if you are intersted in using CAD for creating your robot simulation.

🌱 I’ve done it, you can see the images from CAD, to ROS 2 package, and finally the Gazebo simulation (see the attached images).

Access to the GPU inside the docker container

This is my instruction for creating the URDF and Gazebo simulation for your robot:

  1. CAD:

1.1: Model the parts of your robot using FreeCAD software and its part design workbench.

1.2: Define proper LCS (local coordinate frame) on each part where the joint will be defined later.

  1. URDF and ROS2:

2.1: Install FreeCAD.CROSS workbench inside FreeCAD. It’s a tool for easy URDF generation from your robot.

2.2: Define the links using CROSS. Add created parts of your robot to the links.

2.3: Define the joints using CROSS. Define parent and child links, and the position of the joint.

2.4: Define the robot material in created robot object from CROSS and use the CROSS tool for mass and inertial property calculator of the link.

2.5: Export ROS 2 package of your robot modelled using FreeCAD and CROSS. It will create the URDF, mesh files, and Gazebo and hashtag#Rviz launch files for your robot.

  1. Simulation:

3.1: Move the generated ROS 2 package to your ROS2 work space.

3.2: Build the package using colcon build.

3.3: Launch the Gazebo launch file of the package.

3.4: Enjoy your simulation and echo state of the joints of the robot using ros2 topic echo /joint_states

✅ If you are interested to learn this by a YouTube video, give me a comment to create it for you. 😊