Abstract
This paper presents an automatic generation method of mechanical assembly sequences from geometric information. The obtained sequences represent how to assemble plural parts which have the same axis of symmetry. The drawing used in assembly planning is a cross-sectional view which includes the axis of symmetry, and it is represented in the forms of pixel map. The system consider the disassembly sequences in place of the assembly sequences to reject unfeasible partial assemblies. Thus the system calculates all the possible partial assemblies by iterating an operation of “disassembling one part” starting from the completed object. Since these partial assemblies equal those used in feasible operations represented in an AND/OR graph, the system can generate the AND/OR graph by solving combinatorial problem of the partial assemblies. The assembly operation is feasible, if two partial assemblies used in the operation have no common part and new partial assembly generated from the operation is one of the feasible partial assemblies which have been calculated before. From the AND/OR graph the system searches a tree with the smallest criterion value, which is the best assembly plan. As a result of simulations we have found that the ratio of the feasible partial assemblies to the considerable partial assemblies gets smaller as the number of parts increases. So it is very useful to calculate the feasible partial assembly previously.
