VPSs Based Manufacturing System Mode And Its Application Research

Due to the competation of international market, manufacturing industry is facing the stress of staifying customers with small batch production and rapid response to dynamic market. Conventional manufacturing systems can' t meet such requirements of adaptive ability and agility. It is challenge for modern manufacturing sytem mode. This is to say how to suit the market rapidly, effectively and economically. Just under such background, the advanced manufacturing system mode is dissucessed in this dissertation. To get the agility of manufacturing system, an advanced system named Virtual production systems (VPSs) is proposed. Related key support technology such as building, modeling, controlling of VPSs are throughly explored.The important ideas in this dissertation are listed as follows:1. Thorough summary and analysis of advanced manufacturing system mode. Manufacturing resource organization, system modeling, and scheduling and control of manufacturing system are summarized and analyzed. Related research status and developing trends of respective fields are described. These works gave out straightforward directions of this dissertation.2. On the problem of "manufacturing resource organization mode" : An agile manufacturing system organizing method named Virtual production systems (VPSs) is proposed. Basic profile of VPSs, resource agent and the system framework are analysized. Also, the building algorithem of VPS is discussed. Under this advanced manufacturing philosophy, manufacturing resources are chosen by heuristic algorithm and grouped together rapidly to build up a VPS oriented specific product.3. As for modeling of VPSs, an improved advanced Petri nets are used. In this part, requirement analysis of manufacturing syetme modeling is summarized firstly, and then general model of manufacturing resource is set up according to the researching status of resources, and lastly Colored Timed object-oriented Petri Nets (CTOPNs) model of system is built up. Time factor is also integrated to the CTOPNs model, thus performance analysis can be done. This also builds up solid basement for system scheduling and control. Moreover, to handle the dynamic system change under agile manufacturing environment, the structure changing algorithm of model is proposed. Based on this algorithm, the further model can be easily re-configured than build up other new model.4. About the control system, using hybrid control architecture, which is based on multi-agent technology and composed of cell coordination agent, task agent, VPS agent, and manufacturing resource agent, manufacturing system can execute the effective control to multi-site resources to support the rapid response to customer demands. The autonomy and coordination mechanism is applied to coordinating and scheduling the requests from different tasks and resources, which make manufacturing system flexible, adaptive and robust. The communication mechanism among agents is also discussed combined with the CTOPN modeling and realization of agents. Expecially for VPS agent, an adaptive controller is designed.5. As for important item of system theory, the rough framework of systematical analysis and evaluation of VPSs is proposed. The hierarchy evaluation architecture based on Delphi method is presented. Some important indexes, including time, cost, and adaptability are discussed.