Geometric Relations between Rigid Bodies: Semantics for Standardization

Rigid bodies are essential primitives in the modelling of robotic devices, tasks and perception, starting with the basic geometric relations such as relative position, orientation, pose, linear velocity, angular velocity, and twist. This paper explicitly states the semantics of all coordinate-invariant properties and operations, and, more importantly, all the choices that are made in coordinate representations of these geometric relations. This results in a set of concrete suggestions for standardizing terminology and notation, allowing programmers to write fully unambiguous software interfaces, including automatic checks for semantic correctness of all geometric operations on rigid-body coordinate representations. A concrete proposal for community-driven standardization via the Robot Engineering Task Force [4] is under preparation.