The Research And Development Of Brake Test-Bed Performance Monitor And Fault Diagnosis Expert System

Brake system is a very important and essential part of modern motorcars, which main function is to slowdown or stop the running motorcar, and level off the speed of the motorcar when it is coming downhill and the motorcar itself when it is resting.The quality of a motorcar and the safety of drivers and passerbys are directly related to whether the brake system is healthy, so it is not surprised to find that the brake manufacturers are focusing more and more attention and energy on improving the quality of brake system by adopting more and more sophisticated and accurate production and testing devices. But the traditional testing devices of brake are just combinations of mechanical and electrical devices, which main tasks are just data calculation and signal processing, so they are far away from intelligent testing and becoming more and more difficult to keep up with modern industrial production.This paper introduces the thoughts and methods of expert system into the performance monitor and fault diagnosis of brake system in the cooperative motorcycle brake system testing devices project of the Automobile Engineering Department of Wuhan University of Technology and the motorcycle brakes manufacturer, and has developed a performance monitor and fault diagnosis expert system of brake system on the basis of brake testing bed.The core thought of this paper is to compare the standard performance and function of the brake system which is going to be tested with its practical performance and then analyze the condition of brake from both safety and economy aspects. The fault diagnosis expert system will motivate the reasoning mechanism to find out what caused the malfunction of brake system if there is any malfunction has been found, and then give an explanation to the users.The main works this paper has done are as follows:According to the layer characteristic of brake fault diagnosis knowledge, this paper adopts fault tree to represent the state-space of motorcycle brake faults after thorough research into the structure and makeup of motorcycle brake system, uses framework to represent fault tree nodes and rules to connect fault tree nodes with each other, and then combines framework knowledge expression and production rules knowledge expression to represent the fault tree. The framework which be used to represent fault tree nodes contains rules and then be connected with each other by rules to construct the fault trees. At last this paper realizes the knowledge bases based on Access database.The reasoning machine is realized with both forward and backward mixed reasoning control mechanisms, depth-first and breadth-first mixed search method on the basis of fault trees. The depth-first search is realized with forward reasoning and the breadth-first search is realized with backward reasoning, and then the heuristic search which improved search efficiency greatly is realized with forward and backward mixed reasoning.Explanation mechanism is also an important trait which made expert systems differ from traditional programs. So, this paper adopts prepared text method and execution trace method to realize the explanator of the expert system on the basis of knowledge bases and reasoning machine according to the characteristics of brake knowledge.This paper developed the entire expert system with Visual C++ 6.0 development tool and Access database under Windows XP operating system according to the demands of brakes manufacturer. The interface of this expert system is traditional and classical dialog of Windows. This expert system could not only diagnoses the common faults of motorcycle brake and gives the reasoning results and explanations, but also provides a knowledge acquisition module for users to change or enlarge the knowledge base. The users could also operate various peripheral devices on the testing bed and configure experiment parameters through this expert system. The expert system could not only displays the real-time collected data in three ways as numbers, meters and curves but also stores and prints the experiment results.