Feasibility study of disassembly task based on topological operations-consideration in 2-dimensional space

An automatic generation of assembly or disassembly sequence is a significant problem for an automatic assembly using robotic manipulators. This problem can be separated into following three stages. 1. Extraction of all feasible assembly/disassembly tasks. 2. Generation of all assembly/disassembly sequence. 3. Decision of optimal sequence. As for the stages 2 and 3, one of the efficient strategy based in the AND/OR graph has been proposed. However, as for 1, previous researches are not efficient. In this paper we propose a new technique for the examination of the feasibility of each assembly/disassembly task by using topological operations. The presented method is expected to execute with smaller computational amount compared with the previous methods, because a separating path of a mechanical part without collision with other parts is obtained without search of all space. A mapping, which maps shape of a subassembly to a feasible path of the other subassembly around the first subassembly, keeping contact, is introduced. An area of feasible translational motion of the second subassembly without interaction with the first is calculated. Criteria of feasibility of disassembly task are presented. Finally, we show a simple example to verify the proposed algorithm