Simulator

Our simulator is capable of simulating all sensors of the physical FreiCar. The simulator comes with the docker image and thus does need to be installed manually.

Starting the Simulator

The simulator together with some necessary ROS-nodes can be started by running:

roslaunch freicar_launch local_comp_launch.launch

The simulator needs always to run if you want to start your own programs. Your ROS-nodes must be started in a separate launch file. In this launch file also the map is specified. See down below how to change it.

Updating the Simulator

We might update the simulator from time to time. When a new simulator version comes out you can upgrade the simulator by running update_simulator.bash from the docker directory.

Simulated Sensors/Actuators

Throttle, Steering, Brake

All cars can be controlled over throttle, steering and brake. The corresponding ROS-message can be looked up here and can be sent to /AnyCarName/control.

Localization

If the competition mode is turned off (see explanation below), a ground-truth localization will be provided as tf-transform from /map -> /AnyCarName/handle (center of the car). You can use a ROS tf-listener to query this transform in your code.

Odometry

The odometry of the car is provided on the topic /AnyCarName/odometry using the odometry message message type.

RGB Camera

The RGB image of the front facing camera is published as ROS image message on the topic: /AnyCarName/sim/camera/rgb/front/image.

rgb_sensor

Depth Camera

We also provide a depth image (also as ROS image message) ,which is aligning with the RGB camera, on the topic : /AnyCarName/sim/camera/depth/front/image_float. The depth image is encoded as single channel floating point image and the unit is meters.

depth_sensor

Lidar

We simulate the Sick lidar on the topic /AnyCarName/sim/lidar as PointCloud2 message. After receiving the message in one of your nodes we recommend converting the PointCloud2 message to a pcl format for convenience.

Maps

We have prepared various urban and race maps that can be loaded into the simulator.

In order to change the map open the file local_comp_launch.launch from the package freicar_launch and change the map_name to the corresponding map-name in the table below.

You can also provide the map_name as command-line argument like: roslaunch freicar_launch local_comp_launch.launch map_name:=freicar_race_1.aismap

Preview ROS Map Name (local_comp_launch.launch)
alt text freicar_1.aismap
alt text freicar_2.aismap
alt text freicar_race_1.aismap
alt text freicar_race_2.aismap

Competition Mode

By default, the simulator provides ground-truth localization (a tf-transform from /map to /car_name) and ground-truth odometry. However in the final competition this information won't be available. In the local_comp_launch.launch a argument named comp_mode is defined (default: false). If comp_mode is set to true the ground-truth localization is not published anymore. The simulated odometry measurements are always overlaid with gaussian noise, no matter how the comp_mode is set.

Like the map-name you can set the comp_mode as a command line argument like: roslaunch freicar_launch local_comp_launch.launch map_name:=freicar_1.aismap comp_mode:=true

In the final competition comp_mode is set to true.

Note: Even though if comp_mode is turned on other dynamic agents (See section about spawning dynamic cars down below) will publish ground-truth localization information on the topic /car_localization . It is NOT allowed to use this topic during the competition.

Spawn Poses

There are two ways to define the initial spawn pose of the car:

  1. The freicar_carla_proxy node provides the parameters spawn/x, spawn/y, spawn/z and spawn/heading that can be used to setup the initial pose. Note that if you use the sim_base.launch these parameters are getting overwritten by the values defined in this launch file.

  2. Additionally, freicar_carla_proxy provides the parameter use_yaml_spawn. Note again that if you use sim_base.launch the value gets overwritten by the file. If use_yaml_spawn is set to true the spawn pose will be read from the files located in freicar_base/freicar_launch/spawn_positions depending on the map that is defined by the global parameter map_path (set in sim_base.launch). If the spawn position is used from the yaml file also the ros-parameter spawn/x etc will be set accordingly.

The heading angle is in degree and defined as follows:

angle_definition

Reset/Set Car Positions Manually

After spawning a car two ROS services are created (by freicar_carla_proxy). - /FREICAR_NAME/set_position (e.g /freicar_1/set_position) - /FREICAR_NAME/reset_position (e.g /freicar_1/reset_position)

These services can be used to either reset the cars position to the spawn pose or to set a custom pose. In both cases the car will be beamed to the changed pose.

Set a new pose

Example to set a new pose (in case the car is called "freicar_1"):

rosservice call /freicar_1/set_position "{x: -0.3, y: -0.3, z: 0.0, heading: -45.0}"

Reset to spawn pose

Example how to reset the cars pose to the spawn pose (in case the car is called "freicar_1"):

rosservice call /freicar_1/reset_position true

Spawning Dynamic Cars

In order to test your system with other dynamic traffic participants you can spawn multiple other scripted cars that obey the traffic rules.

To do so, run: rosrun freicar_executables freicar_carla_agent_node 5. This will spawn 5 other dynamic cars. Note that the simulation has to run before.

Using a Gamepad

If you like you can use a gamepad to control your car. Just type: roslaunch freicar_launch start_joystick.launch name:=freicar_anyname where "freicar_anyname" is your car-name. We support currently xbox controllers, but you could change the "FreiCar Joy" node to your needs (see Freicar Overview)

angle_definition