step2-getting-started-with-f1tenth-gym.md

Launching the Simulation

Docker

cd ~/path_to_ws
docker compose up

The above command launches racers with default config. If you want to override the default configuration for racecar1, just go to its config and adjust the parameters for your needs.

• For instance if you'd like to change the name of your racecar1:

/**:
  ros__parameters:
    twin_url: "http://ditto:[email protected]"
    anonymous: false
    prefix: muto
    namespace: org.eclipse.muto.sandbox
-    name: hackracer-01
+    name: fast-racer-01
    type: real_car
    attributes: '{"brand": "Traxxas", "model": "Slash 4x4"}'
    stack_topic: "stack"
    twin_topic: "twin"

Same goes for racecar2 config

/**:
  ros__parameters:
    twin_url: "http://ditto:[email protected]"
    anonymous: false
    prefix: muto
    namespace: org.eclipse.muto.sandbox
-    name: hackracer-02
+    name: slow-racer-02
    type: real_car
    attributes: '{"brand": "Traxxas", "model": "Slash 4x4"}'
    stack_topic: "stack"
    twin_topic: "twin"

To stop the simulation:

• Press Ctrl + C

cd ~/path_to_ws
docker compose down

Native

1. To launch the simulation, make sure you source both the ROS2 setup script and the local workspace setup script. Run the following in a bash session

source /opt/ros/<your-ros-distro>/setup.bash
source install/local_setup.bash
ros2 launch f1tenth_gym_ros gym_bridge_launch.py

An Rviz window should pop up with the default simulation config

Configuring the simulation

1. Open sim.yaml.

2. The map can be changed via the map_path parameter. You'll have to use the full path to the map file. The map follows the ROS convention. It is assumed that the image file and the yaml file for the map are in the same directory with the same name.

   • Don't include the .yaml extension to map_path parameter

3. The num_agent parameter determines how many racers the simulation should expect. This can be changed arbitrarily between [1, 3].

   • Supported number of agents will be increased. For now it is limited to maximum of 3 agents as there occurs performance issues after 3 agents.

1. Topics published by the simulation

Assuming the num_agent parameter in sim.yaml is 3:

• racecar1/odom
• racecar1/scan

---

• racecar2/odom
• racecar2/scan

---

• racecar3/odom
• racecar3/scan

---

If you have tf2_tools installed, you could view the transform tree to get a better idea of what's going on in the simulation backend via below command:

source /opt/ros/<your-ros2-distro>/setup.bash
ros2 run tf2_tools view_frames.py

Above command is going to output you a .pdf file under the directory you've executed the command.

2. Topics subscribed by the simulation

• /map: To receive the map of the environment

• /initalpose: This is the topic for resetting all of the agents' poses to their initial state via RViz's 2D Pose Estimate tool. You need to choose the specific agent you'd like to reset via MultiagentPanel (Which is the Rviz Plugin that comes with the simulation):

---

• Below are the topics to get your racecars going
  • racecar1/drive
  • racecar2/drive
  • racecar3/drive

Exploring Rviz Environment:

• Make sure you've completed the Launching the simulation step:
• If you use Docker, you need to connect to NoVNC server to be able to see Rviz.
• You should be able to observe something similar to below:

- Notice the white square at the center. That means, racecar robot descriptions are not published yet and the simulation is not in a started state. To accomplish that, click the `Start Race` button on the bottom left of Rviz. - After you clicked the `Start Race` button, it shoud look like:

• Now the simulation is in a ready state waiting for you to send control inputs to the racecars!

Next Step

• Head over to the racecar configuration file to get your racecar moving!