On the application of coloured Petri nets to computer aided assembly planning

The problem of assembly process planning is particularly critical for the automation and integration of production, due to the combinatorial complexity and the requirement of both flexibility and productivity. Several planning methodologies and techniques have been proposed in the literature, using an approach limited to specific product typologies and structures. Some of them are more suitable for dedicated automated assembly and assembly lines than for flexible automated assembly and flexible assembly systems (FAS) and assembly job shops. Due to the time-based competition, both cycle time reduction and task parallelism increase require a technique suitable to the generation of assembly plans with flexibility, efficiency and parallelism. The paper presents and discusses the application of coloured Petri nets (CPN) and timed coloured Petri nets (TCPN) to the computer aided assembly planning (CAAP) problem, both to online and off-line planning, and presents a prototype CAAP architecture, that is implemented and validated by means of the assembly planning of an industrial product.<>