---

name: digital-twin description: "Guides the real Go2 LowState to Jetson to Isaac Sim twinbot bridge, DDS discovery, IMU/joint mapping, and kinematic playback diagnosis." disable-model-invocation: true metadata: disco-role: operating license: BSD 2-Clause

Digital twin

Use this route when a physical Go2 should drive a simulated Go2, when /real_dog/joint_states or /real_dog/odom is missing, or when the simulated robot has incorrect joint pose/orientation. The sim-side launch is the bundled simulation adapter with --twinbot; do not rely on an unbundled source launcher.

Topology

The bridge has two operator-controlled processes: a CycloneDDS reader on the Jetson subscribes to Unitree /lowstate; a FastDDS publisher forwards standard JointState and Odometry messages to the Isaac host. The Isaac process then uses TwinbotSubscriber to overwrite joint state and root pose after each physics step. The bridge and sim must be diagnosed as separate sides.

Safe workflow

1. Read references/twinbot-workflow.md and confirm the Jetson ROS 2 Humble/Unitree SDK environment, Ethernet interface, Wi-Fi discovery, RMW choices, and operator permissions.
2. Run the bundled bridge helper without --run first; its default is a configuration-only dry run. Use --run only on the Jetson with the required packages and robot-side authorization.
3. Confirm /real_dog/joint_states and /real_dog/odom before starting the sim with --twinbot.
4. If joints are wrong, use the exact motor order and name mapping in references/message-mapping.md. If the body flips or is half-blended, check IMU odometry and the post-step kinematic override before changing gains.

Read references/troubleshooting.md for DDS, queue, message, quaternion, and stale-data failures. This route never performs SSH, changes network configuration, or sends commands to a real robot by itself.

Limits and verification

Twinbot is visual real-to-sim playback, not a claimed learned Sim-to-Real loop. The current implementation pins sim XY/Z at spawn because IMU data has no absolute position. IsaacLab 0.54.3 and the Jetson runtime were unavailable when this skill was built; no live bridge or full sim verification is claimed.