Hello, I have a problem that I can’t get out of the business. We are an autonomous vehicle team participating in competitions and last year we decided to switch to gazebo this year while using another simulation environment. We created the map, let’s call it map.sdf and we can open it in gazebo in a nice way. We got the vehicle and wheels from the mechanics in separate stl files, converted them to dae to use in gazebo and created a vehicle.sdf file. We can open this sdf file in gazebo and the vehicle comes with the map. I also added sensors such as camera, imu, lidar on it. I can also get data from these sensors. I was able to get the camera image from rviz2, for example, and there is no problem in this part. The problem starts like this. We cannot move this vehicle. We have been trying to do this for about 3 or 4 weeks, but nothing happened. For example, I give speed to the topic from the terminal, this speed value also appears in that terminal due to the launch file, that is, it can receive data from the topic, but the vehicle does not move. I am not sure if it cannot reach the vehicle from this part. I think I have defined the joints properly, but we could not fully integrate the vehicle. Also, only when I run the map.sdf file, for example, the map comes, but only when I run the vehicle.sdf file, the vehicle does not come. I would be very happy if you can help me.