Abstract: Modelling apparatus for modelling a robotic system, the modelling apparatus configured to: model the robotic system with a model, the model comprising instances of at least a subset of a set of defined types interconnected with links, each instance being a description of an element of the robotic system, the links between the instances representing relationships therebetween; and validate the model against validation rules by determining whether the model satisfies those rules, wherein the validation rules comprise: a definition of one or more directed acyclic graphs of the defined types interconnected with parent-child relationships, the defined types corresponding to nodes and the parent-child relationships corresponding to directional edges of the one or more directed acyclic graphs, each defined type defining type rules for that type which an instance of that type must satisfy in order to be valid, each parent-child relationship between a pair of the types defining those types as parent and child types re

Abstract: 1.