State, control, and Operations

FastSim separates reading the world, deciding an action, and executing physical control. Different producers may use different algorithms, but all share one authorization, timing, cancellation, and audit path inside Runtime.

State reads

Scene, Frame, Geometry, and Control Context return stable value objects carrying run, generation, revision, or tick. Callers observe a committed boundary rather than a mutable backend container.

Control targets

control.targets() exposes authorized actors, resource groups, axes, command spaces, and controllers. Producers discover targets before constructing commands and do not guess native degree-of-freedom ordering.

Control chunks

A producer submits a time-aware Chunk. Runtime validates generation, resources, units, schedule, and authorization, then applies it through UniRoboSim at control-tick boundaries. Rule-based, Model, Teleop, and remote Server control use the same executor.

Operations

Asynchronous submission returns an Operation with its own ID, status, result, cancel, and release semantics. A waiting timeout does not mean the Operation was cancelled. Reset and close invalidate old-generation work and complete cleanup explicitly.

Arbitration

When producers overlap a resource, compiled authority and priority determine admission and preemption at the common control boundary. Plugins do not arbitrate by calling each other or racing to write the final command frame.

Planning algorithms remain outside Core. A plugin may capture coherent scene/frame/geometry/target data, compute in its own worker, revalidate, and submit physical chunks. See Application API and Python SDK.