Research on OPN-based multi-agent modeling of collaborative digital assembly system

The purpose of the research on collaborative digital pre-assembly technology is to offer an environment and some related tools to evaluate product assemblability, reduce modification or rework caused by design error and enhance competition ability of enterprise. Considering the characteristics of collaborative assembly in network, an architecture based on Multi-Agent modeling of collaborative digital assembly system is presented, which includes collaborative client (CC) and system server (SS). According to its function collaborative client is divided into communication agent, cooperation agent and application agent, system server is comprised server agent and data-base. Each intelligent agent composing the system the behaviour modeling is built by using object oriented- Petri net. The various states and events can be described by P and T of OPN, and then the transition between state and event is described by colored Taken. The object communication net among these agents is built, and the color of Token that is the structure of correspond is given. Each OCN of agent is analyzed to calculate the related matrix, initial token and t-invariant to detect the deadlock which the system has. Then the collision in the Petri net is analyzed and solution method is given. on the basis, agent structure, which includes GUI, message I/O, message management, state list, function calculation, reasoning engineer and knowledge database, is designed. Finally, a web-based digital pre-assembly system (e-DPAS) is developed, which developed in VC++6.0 program environment by using OpenGL graphics engine and CJLibrary 6.08C extended database. A case study is also introduced to illustrate it.