Web dashboard

The dashboard shows a running car in a browser: the map as it is built, the LiDAR scan, the car’s pose, the camera, and the plan and binding limit from drive intent. It lives at dashboard.sfuracerbot.ca, behind a sign-in with a team email. The car runs only the server side, web_dashboard, and the site connects to it.

The dashboard publishes to no ROS topic, so it can run beside any mode, including a race. Its code, the site and its full manual are in the sfu-racerbot/web-dashboards repository, included in the workspace as the src/web_dashboardsGitHub submodule.

What it reads

web_dashboard_node subscribes to the topics below and forwards what it needs to the browser over one WebSocket connection. It publishes to no topic.

Car telemetry goes to the browser at up to 20 Hz (telemetry_rate_hz). The map, the heaviest message, is the one the compression and patching exist for.

Start it

ros2 launch racerbot_launch dashboard_launch.py

The log reports the server listening on port 8080, and the site lists the car as CAR ONLINE. dashboard_launch.py loads the car’s own settings on top of the dashboard’s generic defaults.

The camera stream goes straight to the browser and publishes no ROS image topic. To start the LiDAR and the camera for bench testing, without any driving stack, use ros2 launch racerbot_launch dashboard_test_launch.py. It does not start a second dashboard, because the cars already run one at boot and a second copy fails on the busy port 8080. Add dashboard:=true only on a computer where no dashboard is running.

What it can change

The dashboard has four write paths, all bounded:

How live tuning works

Each driving node publishes a read-only parameter, live_tunable_spec: a JSON catalogue of the parameters it accepts live, with their group, bounds, unit and step. The dashboard reads the catalogue and builds its sliders from it, so it never needs to know a node’s parameters in advance. An entry in gap_follow’s catalogue, from live_tuning.pyGitHub:

Tunable('max_lateral_accel', 'Speed', 0.3, 4.0, unit='m/s^2', step=0.1,
        description='Cornering aggression: speed is held to '
                    'sqrt(a_lat / curvature) for the steering angle '
                    'being commanded.'),

A change goes to the node through the standard ROS set_parameters service. The node checks it in its own parameter callback, against the same bounds and every rule that ties parameters together, and refuses anything outside them, so the dashboard cannot set a value the node would not accept from its YAML. Save writes the accepted values back into the node’s YAML file, listed per car in tuning_config_files.

Live tuning is the fast way to tell a profile problem from a controller problem between runs: lower pure_pursuit’s max_speed and the whole profile is clipped without recording anything again. Steering-law parameters cannot be tuned live; the node refuses.

The contract between the dashboard and the driving nodes, the live_tunable_spec format and the YAML save, is tested on both sides. This workspace’s half is in test_gap_follow_live_tuning.pyGitHub and test_pure_pursuit_live_tuning.pyGitHub.

Lichtblick

foxglove_bridge starts at boot as the foxglove-bridge system service and lets Lichtblick, an open-source Foxglove-style viewer, display any topic. Browsers can publish to no topic through it. With client publishing on, the bridge’s topic whitelist was not enforced in version 3.5.0, and a client’s /drive reached ackermann_mux past every LB check, so client publishing is off and a test fails if it is turned back on.

Change a car’s settings

Edit the car’s settings file in racerbot_launch/config/, not the package’s YAML in the submodule, which holds the defaults every team shares. Then run the tests that check it:

python3 -m pytest src/racerbot_launch/test/ -v

They catch a misspelt key, which ROS would otherwise ignore without a warning, a LiDAR offset that disagrees with the bringup transform, and a process or folder the dashboard would drop.

If the site cannot reach the car

On the car:

ros2 run web_dashboard remote_check --site https://dashboard.sfuracerbot.ca --car rb1

Use rb2 on car 2. It ends with Everything this car can check is fine when the car’s side works, and otherwise names the step that fails. http://<car-ip>:8080/ returns 404 on purpose: the car serves no page itself.