Study On Fault Diagnosis Expert System For Cable Based On CAN Bus

There are hundreds of cable in a certain type armored vehicle and all over the car body,and connectors more,connection relationship is complex.Each cable often contains a number of wire harness.Because of the bad combat and training environment.It is very difficult to find fault cable once the fault take place.For as many as thousands of wire points,blindly use wire detector test one by one is a waste of time.And some high pressure test will cause the damage of good cable.Unable to meet the requirement of rapid diagnosis cable fault in original state.For this purpose,the paper according to the relationship between cable system and the whole car functional units,developed a set of expert system to diagnosis cable system fault.The main research contents are as follows:Firstly,designed the hardware of the expert system.The distributed information collection and wire test structure based on CAN bus.Collecting the working parameters and self-check information of the functional units.Get preliminary information to diagnosis cable fault,then conduct wire test on the fault cable to get the final result.Achieve the goal of collecting parameters decentralized and process it centralized.Provide the expert system for reasoning facts.Secondly,the study about knowledge acquisition of cable fault diagnosis is carried out.The improved ARDM algorithm based on rough set theory and the method of building up fault tree were used to acquire knowledge.Solved the difficult problem of knowledge acquisition on diagnosis expert system.In order to select a fault tree,used the improved ARDM algorithm to mining top event of one fault tree.To solve the minimum cut sets of the fault tree,that are all the fault modes of the top event.Thirdly,designed the knowledge base and reasoning mechanism about cable fault diagnosis expert system.Adopting production rule said the knowledge of fault diagnosis expert system,and Access 2007 database to build knowledge base and store knowledge.Through the Visual C++6.0 to design program on the knowledge base management and maintenance.The knowledge organization characteristics about cable fault were analyzed,then designed the reasoning machine of cable faultdiagnosis expert system based on KMP fast pattern matching algorithm.Improved the efficiency of diagnosis.Finally,Studied the software implementation of cable fault diagnosis expert system.According to the basic structure of expert system,designed each module of cable fault diagnosis expert system software,and used the Visual C++6.0 and Access2007 database to jointly develop the software of cable fault diagnosis expert system,make the function of each module.