基于粗糙集理论的卫星故障诊断方法

METHOD OF SATELLITE FAULT DIAGNOSIS BASED ON ROUGH SET

卫星结构和控制的复杂性、独特性和诱发故障的多源性导致其故障诊断的困难。卫星的一种故障模式与许多症状变量有关,目前的故障诊断推理因未充分考虑症状变量的冗余变量而比较复杂。提出了基于粗糙集理论的故障症状约简新方法,用卫星故障实例研究了新方法的应用,结果表明该约简方法对消除卫星故障症状信息冗余、简化和优化故障诊断推理非常有效。

The fault diagnosis of satellites is a difficult problem due to the complex and unique of structure and control of satellite and the presence of multi-excite sources. Generally, one satellite fault mode is relative to many symptom variables. These variables comprise a set, called the primary symptom set of the fault mode. If each variable in the primary symptom set is necessary to the fault diagnosis? The answer is 'no'.That is, some variables in the set are redundancy variables. Current reasoning method of fault diagnosis uses all of the variables of primary symptom set to diagnose fault. Because of the redundancy variables in the set, the reasoning method is usually complicated. The redundancy variables not only give no contributions to the fault diagnosis, but also affect the accuracy of the fault diagnosis. So, the methods that can remove the redundancy variables in the primary set should be found. Rough set is a kind of advanced uncertainty reasoning theory. It has several advantages. One of them is to be used to simplify and optimize the sets, which have redundancy variables. Based on Rough set, a new method of satellite fault diagnosis is proposed in this paper. This method removes the redundancy variables in the primary symptom set of satellite fault mode firstly. The remainder variables comprise a set, called the reduction symptom set of satellite fault mode. Then, on condition that the diagnosis accuracy is guaranteed, the proposed method only uses the variables in the reduction symptom set to diagnose fault. The diagnosis reasoning is relatively simpler, because it uses fewer variables to diagnose fault. The content of this paper is organized as following: Firstly, the shortage of current methods of satellite fault diagnosis and the necessity of applying Rough set to satellite fault diagnosis are analyzed. Secondly, the theoretical method of Rough set for diagnosing satellite fault is briefly studied. Thirdly, the practical application of the method is given. Finally, the proposed method is discussed and the conclusions of this paper are given. It is shown that the method proposed in this paper is effective for satellite fault diagnosing.