Manufacturing systems are in a dynamically changing e nvironment with uncertainty. Management of complexity, changes and disturbances is one of the key issues of production. The traditional hierarchical control of CIM...Manufacturing systems are in a dynamically changing e nvironment with uncertainty. Management of complexity, changes and disturbances is one of the key issues of production. The traditional hierarchical control of CIM systems limits the agility and the flexibility of the shop floor control sys tems and makes the reconfiguration and maintenance of shop floor control systems need high cost and much time. So new architectures are required to meet these c hallenges for the shop floor control systems. Recent fundamental research in distributed artificial intelligence and related applied research in intelligent manufacturing systems have shown that the Multi -Agent based system is one of the most promising methods. In a multi-agent man ufacturing system, the agents react to the information acquired from environment and communicate with other agents to co-operate to solve the global problem. I n this paper, a framework of reconfigurable shop floor control system based on m ulti-agent is presented. The concept of dynamic and logical manufacturing cell is proposed to organize manufacturing resources to achieve the ability of re configuration in dynamic shop floor environment. The framework is composed of three levels. First, the level of shop floor comp rises order agent, resource management agent, product management agent and t ask agent. Second, the level of dynamical cells consists of production agents an d control agents. Finally, the resource agents, such as AGV agents and machine a gents, belong to the equipment level. The control architecture in the framework is different from hierarchical control. It is hybrids of hierarchical and hetera rchical control architecture. The Contract Net protocol and its bidding mechanism are suitable and efficient t o implement the dynamic and logical manufacturing cells. Based on the Contract N et Model, dynamic negotiation during the process of forming the dynamic and logi cal manufacturing cells is analyzed in the paper. In this paper the dynamic and logical manufacturing cell is the basis of the r econfiguration of multi-agent systems. It is organized in logical way while the traditional cell based on GT (group technology) is organized in physical way. I n the framework, resource agents are organized according to orders coming to sho p floor, and dismissed when the tasks are finished. Dynamically created cells ca n be overlapped in shop floor so that resource agents may belong to more than on e dynamic and logical manufacturing cells at a time. The order-oriented product ion agents and control agents that are created dynamically exist for the dur ation of the task and are destroyed when the task is completed. They have the li fecycle of creation, execution and destruction. Control agents are the coordinat ors and monitors that are responsible for organizing resource agents and monitor ing disturbances, but they are not strict controllers. They may recruit new reso urce agents into cells when disturbances such as machine breakdown appear. In the paper, the software architecture of shop floor control system based on Multi-Agent is also presented. And the distributed object technology based on C ORBA and KQML language are discussed.展开更多
文摘Manufacturing systems are in a dynamically changing e nvironment with uncertainty. Management of complexity, changes and disturbances is one of the key issues of production. The traditional hierarchical control of CIM systems limits the agility and the flexibility of the shop floor control sys tems and makes the reconfiguration and maintenance of shop floor control systems need high cost and much time. So new architectures are required to meet these c hallenges for the shop floor control systems. Recent fundamental research in distributed artificial intelligence and related applied research in intelligent manufacturing systems have shown that the Multi -Agent based system is one of the most promising methods. In a multi-agent man ufacturing system, the agents react to the information acquired from environment and communicate with other agents to co-operate to solve the global problem. I n this paper, a framework of reconfigurable shop floor control system based on m ulti-agent is presented. The concept of dynamic and logical manufacturing cell is proposed to organize manufacturing resources to achieve the ability of re configuration in dynamic shop floor environment. The framework is composed of three levels. First, the level of shop floor comp rises order agent, resource management agent, product management agent and t ask agent. Second, the level of dynamical cells consists of production agents an d control agents. Finally, the resource agents, such as AGV agents and machine a gents, belong to the equipment level. The control architecture in the framework is different from hierarchical control. It is hybrids of hierarchical and hetera rchical control architecture. The Contract Net protocol and its bidding mechanism are suitable and efficient t o implement the dynamic and logical manufacturing cells. Based on the Contract N et Model, dynamic negotiation during the process of forming the dynamic and logi cal manufacturing cells is analyzed in the paper. In this paper the dynamic and logical manufacturing cell is the basis of the r econfiguration of multi-agent systems. It is organized in logical way while the traditional cell based on GT (group technology) is organized in physical way. I n the framework, resource agents are organized according to orders coming to sho p floor, and dismissed when the tasks are finished. Dynamically created cells ca n be overlapped in shop floor so that resource agents may belong to more than on e dynamic and logical manufacturing cells at a time. The order-oriented product ion agents and control agents that are created dynamically exist for the dur ation of the task and are destroyed when the task is completed. They have the li fecycle of creation, execution and destruction. Control agents are the coordinat ors and monitors that are responsible for organizing resource agents and monitor ing disturbances, but they are not strict controllers. They may recruit new reso urce agents into cells when disturbances such as machine breakdown appear. In the paper, the software architecture of shop floor control system based on Multi-Agent is also presented. And the distributed object technology based on C ORBA and KQML language are discussed.
