CARLA ROS Bridge Tutorial

Link To Oficial Carla-Ros-Bridge Repo

0.9.10.1 Version

Start the CARLA Simulator

The CARLA simulator renders a synthetic world where vehicles and pedestrians can interact. It provides network ports 2000, 2001, 2002 for communication with other system components, so you can remote control it and retrieve world information that way.

Use following command to start the CARLA simulator on your local machine.

cd ~/carla_0.9.10.1
./CarlaUE4.sh

Start the CARLA ROS Bridge

The ROS environment is used to exchange messages between system components, allowing for a loosely-coupled system design. As ROS is extremely useful for robotics projects, the CARLA simulator provides an interface for ROS called CARLA ROS Bridge. It supports bidirectional communication between ROS and CARLA by converting between ROS messages and CARLA PythonAPI messages.

Use following command to start the CARLA ROS Bridge on your local machine. This will start a ROS node called carla_ros_bridge.

roslaunch carla_ros_bridge carla_ros_bridge.launch

Spawn an Ego Vehicle

Next, we need to spawn a vehicle that we can remote control.

Use following command to spawn a vehicle by an example definition.

roslaunch carla_ego_vehicle carla_example_ego_vehicle.launch

Later we can override the vehicle's definition, so we can spawn a specific car with our custom sensors, etc.

roslaunch carla_ego_vehicle carla_ego_vehicle.launch \
    sensor_definition_file:=config/sensors.json
# assuming the sensors are located in config/sensors.json

Observe the Ego Vehicle Status

For simply accessing the vehicle status, subscribe to the related ROS topic.

Use following command to subscribe to the ego vehicle status.

rostopic echo /carla/ego_vehicle/vehicle_status

Create a Spectator Camera

Now that we have spawned a vehicle, we need to direct the spectator camera to see it driving.

Use following command to create a spectator camera.

roslaunch carla_spectator_camera carla_spectator_camera.launch

TODO: this doesn't seem to work yet, figure out how this is done

Register an Ackermann Remote Control

As it is, we have spawned a vehicle and are able to see it. Now we need to attach a remote control to the vehicle for driving it. There are multiple solutions for this, but we'll be using the Ackermann control which is designed for remote control by a machine, not by a human.

Use following command to attach an Ackermann control to your ego vehicle.

roslaunch carla_ackermann_control carla_ackermann_control.launch

Like spwaning a vehicle, this can be customized as well to fit the vehicle under surveillance and control.

Send Ackermann Driving Signals

Finally, everything is set up to send some driving signals to the vehicle. As a quick example, we'll be sending it a command to drive straight forward which gets repeated every 10 seconds.

rostopic pub /carla/ego_vehicle/ackermann_cmd ackermann_msgs/AckermannDrive \
    "{steering_angle: 0.0, steering_angle_velocity: 0.0, speed: 10, acceleration: 0.0, jerk: 0.0}" -r 10

All-in-one Launch for Manual Control

As there's a common demonstration use case for launching an ego vehicle that can be remote controlled by a user, there's a shortcut for that provided as a specific launchfile executing all the commands in one go.

roslaunch carla_ros_bridge carla_ros_bridge_with_example_ego_vehicle.launch