Research On Application Of Contract Net-based Collaboration Of Multi-Agent In Job Shop Scheduling

The vehement market competition has taken new challenges to manufacture, so the old productive model doesn't adapt to the requirement of the modernized manufacture, and the study of large scale informational manufacture system has been the topical problem. However, because of complex contents and widespread range, the studies in some fields of informational manufacture system are poor; Job-shop scheduling is one of the studies. The job-shop is the cell of the manufacture system, the control of which effect the performance of the whole system; however, the scheduling problem has the character of numerical problem, so the affective methods and the optimization of scheduling become the key. Nowadays, the development of manufacture focuses on network, intelligent and agility. The Agent technology presents a new approach for the study of job-shop scheduling. Agent has become a hot term in the distributed environment and one of the topics in the artificial intelligence field. In this paper, we propose a Multi-Agent job shop scheduling system based on improved contact net protocol. The main research results of this paper are as follows:(1) A modified contract net protocol has been put foward. Contract Net Protocol is the primary means of collaboration, but in the classic Contract Net, there are many inadequates which have impact the actual collaboration process and the efficiency of task's accomplishment. In this paper, on the basis of the traditional contract net model, DoC (degree of credit),reward and punishment coefficient have been introduced, limit the scope of selecting and bidding,finally, an improved model of contract net protocol has been put forward.(2) In this paper, a model of job-shop scheduling system based on Multi-Agent System has been created, meanwhile, analyse the functions of each agent, realize the negotiation between the homogeneous Agents and equipment Agents on the basis of the improved contract net protocol, and design an algorithm for the job-shop scheduling. (3) A whole design scheme of the shop scheduling system has been put forward and the function of each Agent has been designed. On the JADE platform, the interface of the job shop scheduling system has been designed, experiments have been done to simulate the allocation for the tasks. Through the process of tender -bidding between the homogeneous Agents and equipment Agents, tasks have been allocated successfully. By comparison experiments, we can come to the conclusion that the improved contract net protocol can effectively reduces the collaboration time and information flow.