GAPP - A GENERATIVE ASSEMBLY PROCESS PLANNER

This paper presents results of exhaustive research in automated assemb ly planning. A generative assembly process planner (GAPP) has been dev eloped that takes as input a solid model of the product to be assemble d and outputs its feasible assembly sequences. Once the product has be en modeled as a solid using a commercial solid modeler, the resulting solid model's boundary representation (B-Rep) file is interpreted by t he GAPP to generate mating information among parts in the form of a re lational graph. This graph becomes the input of a search graph process whose constrained expansion reveals all feasible assembly sequences f rom a geometric, stability, and accessibility point of view. The relat ive goodness of different feasible assembly sequences can be determine d using pertinent criteria such as the number of reorientations involv ed or the clustering of similar assembly operations into successive on es. The expansion engine is very flexible and enables many different t ypes of assembly problems to be handled uniformly, for example, findin g disassembly repair sequences not requiring complete product disassem bly or generating assembly sequences that force the building of predef ined subassemblies. Examples with real industrial products are provide d to illustrate the potential of using this tool.