Fault Diagnosis Expert System Of Launch Vehicle Based On Fault Tree

The paper starts with the current situation of launch vehicle fault diagnosis technology, and sets forth that the fault diagnosis being dependent on the expert experience and drawing the fault tree for a short time at the scene have restricted the demands to high efficiency and real time nature of fault diagnosis. For the need adapting to the high density of satellite launching missions, and to improve the efficiency of launch vehicle fault diagnosis, the paper has found the both binding site of the FT analysis and the fault diagnosis ES after researching deeply in the two commonly used fault diagnosis technologies, and has brought forward one kind of new fault diagnosis method, is namely the fault diagnosis ES of launch vehicle based on FT.A large amount of FT-based knowledge is in store and in accumulation, which makes it possible to invoke fault trees for carrying out the fault diagnosis, and improve the efficiency greatly. At the same time, the system owning expert's knowledge and experience is able to replace the expert helping the commander to carry out the fault diagnosis. The system has three main functions such as fault diagnosis, system upkeep, data inquiry etc. It adopts the operation interface of human-computer interaction. After the experiment of function verification by two representative fault trees, the system is proved to be with perfect functions, easy to operate, and convenient to safeguard. It may be an important means of launch vehicle fault diagnosis.In this paper, the main work has been done in three aspects:First, study sufficiently on the FT analysis and the fault diagnosis ES, and bring forword the entire thought of the fault diagnosis ES based on FT and the concrete plan of design; Second, realize the fundamental functions of the system in the environment of Windows XP OS, with VC++ 6.0 as the exploiture implement and Visual Foxpro 6.0 as the database administration implement; Third, carry out the experiment of function verification on the system with two representative fault trees in the test of servo mechanism.Two aspects of key technolog have been resolved in this paper:First, the design of FT-based knowledge structure. 14 data items have been designed for the event node of the fault tree target-oriented. They include all normal information describe and relevant explanation of the event, and can totally satisfy the covering with the data transferred in the course of the diagnosis; Second, the design of reasoning mechanism according with the fault tree characteristic. A pointer-type and forward-direction reasoning method is adopted. And a certain characteristic of uncertainty reasoning is introduced at the same time, which makes the fault diagnosis can answer various complicated situations while diagnosing.It has two respects mainly that the innovation of the paper is lighted:Firsrt, merge two fault diagnosis technologies of FT analysis and fault diagnosis ES, and build the fault diagnosis ES based on FT; Second, strengthen expanding of the knowledge base, which makes the system have the characteristic of framework system concurrently, and benefits gradual completion of the system and broad application in other fields.