摘要: We consider the following problem that arises in assembly planning: given anassembly, identify a subassembly that can be removed as a rigid object without disturbing the rest of the assembly. This is called the assembly partitioni... 展开 We consider the following problem that arises in assembly planning: given anassembly, identify a subassembly that can be removed as a rigid object without disturbing the rest of the assembly. This is called the assembly partitioning problem. Polynomial-time solutions have been presented when the motions allowed for the separation are of certain restricted types. We show that for assemblies of polyhedra, the partitioning problem for arbitrary sequences of translations is NP-complete. The proof applies equally when each part in the assembly is limited to a constant number of vertices; when rotations are allowed; when both subassemblies are requried to be connected; and for assemblies in the plane where each part may consist of a number of unconnected polygons. 收起