Team Spatzenhirn Simulator ROS Interface

This package contains ROS2 nodes for translating between the shared-memory interface of the simulator and ROS messages.

Usage

For our use-case, we have variants of our usual launchfiles that exchange the hardware interface with the simulator interface nodes in this package. The topics named directly correspond to the topics used during real-world driving for us. If this is not the case for you, remapping the names probably works.

SimulatorSpatzNode

Publishes simulated vehicle state and simulation status. The simulation time requires special handling, see the section on time below!

Output Topics

name	type	description
/clock	rosgraph_msgs::msg::Clock	Current simulation time (see time)
/spatz	spatz_interfaces::msg::Spatz	Simulated vehicle state
/rcmode	spatz_interfaces::msg::RCMode	Manual control override (set if paused)

SimulatorDepthNode

Publishes the combined pointcloud of two Intel D435 cameras, as well as a decimated version of the same pointcloud.

Output Topics

name	type	description
/depth/combinedPointcloud	sensor_msgs::msg::PointCloud2	Combined pointcloud of both depth cameras
/depth/combinedFilteredPointcloud	sensor_msgs::msg::PointCloud2	1/4 decimated pointcloud

SimulatorHardwareOutNode

Forwards controller outputs to the simulator.

Input Topics

name	type	description
/control_setpoint	spatz_interfaces::msg::ControlSetpoint	Vehicle steering and velocity command

SimulatorImageNode

Publishes the raw camera image in bayer format, as well as camera calibration data. This node additionally publishes the TF2 transform from the vehicle frame to camera frame (spatz to camera).

Output Topics

name	type	description
/camera/image_raw	sensor_msgs::msg::Image	Main camera image, bayer encoded
/camera/camera_info	sensor_msgs::msg::CameraInfo	CameraInfo corresponding to image_raw
/camera/extrinsic_calib	spatz_interfaces::msg::ExtrinsicCalib	See message definition

SimulatorVisualOutNode

This nodes sends the currently planned trajectory to the simulator for visualization. This node is currently not functional, since a dependency on other parts of our codebase still needs to be resolved.

Input Topics

name	type	description
/trajectory	spatz_interfaces::msg::Trajectory	Current trajectory (TODO: replace with ILQRTrajectory)

Time

Since the simulator (usually) runs slower than real-time, and allows pausing and restarting, the simulator is the ROS time source during simulation. The SimulatorSpatzNode publishes the current simulation time on the /clock topic, for other nodes to use. Note that nodes that wish to use the current time need to be started with the use_sim_time parameter set to true, in order to respect the /clock topic!

In a launch file:

Node(
    package='teamspatzenhirn',
    executable='LaneDetectionNode',
    name='lane',
    parameters=[{'use_sim_time': True}],
)

In the console, for example with RVIZ:

foo@bar:~$ rviz2 --ros-args -p use_sim_time:=true

Status

The provided nodes (with the exception of SimulatorVisualOutNode) should be functional. This is equivalent to what we use internally, although we use a copy of this code in our monorepo which does not contain some of the included utility functions (which originally come from other/shared libraries).

It has been our goal to integrate ROS interface directly into the simulator, but the existence of these nodes currently makes this low priority for us.

Contributing

Contributions are welcomed and encouraged, especially in making this interface less dependent on our custom ROS messages, and more in line with ROS standards (the simulator has been in use for multiple years already when we switched to ROS).

If you changed something to make this work with your own software stack, let us know, and submit a pull request!