A New Method of Model-Based Diagnosis for Spacecraft Propulsion Systems
- Paper number
IAC-08.C4.3.13
- Author
Mr. Wei Zheng, China Academy of Space Technology, China
- Year
2008
- Abstract
The propulsion system is an important subsystem of launch vehicles and spacecraft. With the development of reusable launch vehicles, man-rated spacecraft and autonomous operation technologies, it is important to perform real-time health monitoring or diagnosis on the operation of spacecraft propulsion systems. In order to meet the requirements on real time and accuracy, a variety of model-based diagnostic software tools for spacecraft propulsion systems are developed in the world, such as Livingstone and SHINE, and successfully applied to many spacecraft, such as Earth Observing One (EO-1), DSP-1, X-34 and X-37. At first, this paper summarizes the development of diagnostic technology in recent years, and in particular, analyzes the progress, application and characteristics of the model-based diagnostic technology. Next, based on the above mentioned analysis, as well as in order to solve the problems of real-time and accurate diagnosis, this paper proposes a new diagnostic method for spacecraft propulsion systems with temporal information, which is based on temporal causal graph models and adopts consistency-based reasoning mechanism. Furthermore, this paper puts emphasis on the explanation of the establishment of qualitative models that represent the knowledge of systems, and the reasoning mechanism of the diagnostic method. The establishment of models is to transfer differential equations, which describe the dynamic characteristics of the system, to a causal graph which takes system parameters as nodes and formulates the qualitative relations of system parameters. The reasoning mechanism applies the consistency-based diagnosis theory which is the same with other mode-based diagnosis methods. The solutions of diagnosis are ultimately obtained through combining the search algorithm of graphs and matching algorithm widely used in expert systems. Then, in order to demonstrate the feasibility and effectiveness of the method, a diagnosis example of complex propulsion system is described, and the diagnosis results are compared to the actual faults and analyzed in detail. Finally, this paper presents the advantages and disadvantages of the method when it is applied to propulsion systems and suggests the improvement directions that can be further studied.
- Abstract document
- Manuscript document
(absent)