Disassembly Petri net generation in the presence of XOR precedence relationships

A disassembly process plan (DPP) is a sequence of disassembly tasks which begins with a product to be disassembled and terminates in a state where all the parts of interest are disconnected. Disassembly process planning is critical for minimizing the resources invested in disassembly and maximizing the level of automation of the disassembly process and the quality of the parts (or materials) recovered. In this paper, we propose an algorithm which automatically generates a disassembly PN (DPN) from a geometrically-based disassembly precedence matrix (DPM). This algorithm can be used to generate DPPs for products which contain simple AND, OR, complex AND/OR, and XOR relationships. The resulting DPN can be analyzed using the reachability tree method to generate all feasible disassembly process plans (DPP), and cost functions can be used to determine the optimal DPP. An example is used to illustrate the procedure.