Fuzzy analytical hierarchy process-based assembly unit partition for complex products

Assembly planning is one of the NP complete problems, which is even harder to solve for complex products. Furthermore, development of complex products has been becoming a collaborative activity among different enterprises at the same or different sites. Collaboration among designers is considered as an effective strategy to tackle the difficulty of assembly planning. According to the strategy, the task of assembly planning of complex products is decomposed into several simpler subtasks related to portions of the whole product, and the subtasks are then assigned to the designers in collaboration. In this paper, assembly unit partition is addressed, which means the decomposition of a complex product into smaller assembly units. Assembly unit partition is more complex than subassembly extraction (or identification) because more assembly constraints are taken into consideration. Firstly, different and necessary assembly constraints are analyzed in detail and their related evaluation indices are given for assembly unit partition. Then, the assembly unit model and the decision model of assembly unit partition are proposed. A method of assembly unit partition based on the decision model and Fuzzy Analytical Hierarchy Process (FAHP) method is clarified. The valid assembly units can be determined by analyzing the decision values of assembly relations between two parts and the given conditions. Finally, the validity and effectiveness of the method is verified with an example.