Recording experiments¶

Documentation / Workflows / Recording

Recording is integrated into the launch workflows so the recorder starts before control and is finalized after the experiment process exits.

Lifecycle¶

For the controller launch files that support recording:

start rosbag
→ allow DDS discovery
→ start controller / flight process
→ controller owns experiment completion
→ stop rosbag
→ wait for recorder finalization
→ terminate launch

The launch files currently give the recorder a one-second startup window before starting the controller so early handoff traffic is not missed.

Record a native Position-mode run¶

source ros2/runtime_env.sh
ros2 launch px4_position_takeoff_hover position_takeoff_hover.launch.py \
  record:=true

The bag is placed under the profile-specific bags/ directory.

Record Offboard position¶

ros2 launch offboard_controllers offboard_position.launch.py \
  trajectory:=step_response \
  record:=true

Record SE(3)¶

ros2 launch offboard_controllers se3.launch.py \
  vehicle:=gz_f450 \
  trajectory:=full_excitation \
  handoff:=acceleration \
  publish_diagnostics:=true \
  record:=true

Standalone SE(3) recording defaults to:

bags/se3/<timestamp>/

The SE(3) launch also exposes recording_output:=... so the sequence runner can provide a deterministic study-owned bag path.

Topic ownership¶

Recording selections live with the controller packages, for example:

ros2/src/offboard_controllers/config/recording/

PX4 topics in those files use symbolic names from the central catalog:

config/px4_topics.def

Toolkit-owned ROS topics, such as SE(3) diagnostics, can be listed directly as absolute topic names.

This separation avoids scattering literal /fmu/in/* and /fmu/out/* strings through launch/analysis configuration.

SE(3) recording scope¶

The SE(3) recording profile includes:

PX4 vehicle status/state and estimator/failsafe context
Offboard control mode and the selected handoff setpoints
downstream PX4 trajectory/attitude/rate/thrust/torque setpoints
control allocator status and actuator motors
the toolkit's trajectory reference
optional controller diagnostics when published

Finalization contract¶

The sequence runner treats metadata.yaml as the rosbag completion contract. It only advertises a sequence bag as finalized after that file exists. It then writes experiment.json beside the bag so later analysis can use explicit profile, sequence/step identity, and launch arguments instead of inferring controller configuration from downstream signals.

Analyze a bag¶

./tools/px4_analyze bags/<profile>/<run>

Sequence-study bags live under a study directory; see Sequences.