A Study Of An Adaptive Model And Coorperation Mechanism In MAS-based Fault Diagnosis System

Along with the rapid development of modern industry, the seal of machines and equipments are more and more large, the degree of automation are more and more higher, integrated management are more and more common.,the equipment problem will lead to significant accident and huge property damage.The method of using simple instruments and artificial experience traditionally already can not fulfill the fault diagnosis of modern complex equipment.Recently, mechanical fault diagnosis technology is attached very importance to home and abroad, and rapidly developed into a new subject based on science such as mechanics, communications, computer science and artificial intelligence.It is greatly significant for protecting the normal operation of core equipment to diagnose equipment fault with intelligent system and detecting fault timely.MAS (Multi-Agent System) is a kind of good solve distributed problem technology, and its method and theory have widely applied in many fields.For complexity, distribution and dynamic of modern machinery fault system,MAS can use modular design idea and the parallel distributed processing technology to decompose complex system into relatively independent subsystems, and then achieve relatively complex taskst the Agent interactions and collaboration.Certainly,the process of complex electromechanical equipment diagnosis will appear a lot of new information and knowledge.Facing the dynamic diagnosis environment, MAS fault diagnosis system must be able to adapt its surrounding environment, and construct corresponding model according to the different diagnosis object. Therefore,studying adaptive diagnosis model has important theoretical and practical significance.A good multi-Agent system must be suported by good a coorperation mechanism.Along with the multi-Agent appeared, the study of coorperation are emerging.the coorperation not lnly make the ability of the whole system imoroved,but also increased the flexibility of multi-Agent system.In this paper,contract net protocol is chosen as the coorperation mechanism becaused of the distribution characteristics of sytem.In additon,a improved model of contract net protocol is proposed,that is PC-CNP (Postpone Commitement-Contract Net Protocol).this protocol is make up for the defeciencis of the traditional contract net protocol in resource allocation and communication. Experimental results show that PC-CNP is more efficenct than the traditional contract net.The model, AMFD (Adaptive Model in Fault Diagnosis) based on the model of MAS, is established at the background of some large coal in this paper. The hierarchy of this model is matched with the hierarchical of complex mechanical and electrical equipment, which has distributed and adaptive characteristics. It can optimize the diagnostic system based on the change of diagnostic object through the reconstruction of the topology, agent organizations, diagnostic process and areas of knowledge. In order to standardize the description of the system, this paper uses the formal language of BNF to definite the aspects of structure and composition of the AMFD. Finally, the prototype system of AMFD is carried out in the JADE platform, of which dynamic knowledge management and hierarchical structure enhances the extensible and scalable.