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Glossary

Terms as used in OpenRAL.

  • VLA — Vision-Language-Action model. Maps (images, language, state) → action[chunk]. Examples: π0, GR00T N1.x, SmolVLA, OpenVLA-OFT.
  • WAM — World Action Model. Generative simulator used for mental rollouts and failure anticipation. Examples: Cosmos Predict, Genie 3, IRASim, UnifoLM-WMA-0.
  • rSkill — A packaged, signed, capability-tagged unit of robot behavior. One HF Hub repo. Loaded by rSkill.from_pretrained(...).
  • HAL — Hardware Abstraction Layer. The openral.hal.HAL Protocol; per-robot adapters live in packages/openral_hal_<robot>/.
  • WorldState — A typed snapshot consumed by Skills and the Reasoner. Backed by tf2 + sensor topics.
  • Reasoner / S2 — The slow planning loop (LLM → typed tool calls).
  • Skill / S1 — The fast policy loop (VLA or scripted, action-chunked).
  • Cerebellum / S0 — The C++ realtime layer below S1, where applicable (humanoids).
  • Embodiment tag — A short string (e.g., g1, so100_follower, aloha, oxe_droid) that maps a skill to a robot's heads / action layouts.
  • Trace — An OTel span tree + LeRobotDataset row capturing one execution end-to-end.
  • Replanning ladder — The bounded sequence: retry → param-tweak → substitute → goal-replan → human-handoff.