Research On The Horizon Key Component's Fault Prognostics Methods Based On Time Stress Analysis

The horizon is one of the key parts of helicopter,its working state directly influences the reliability and the readiness of the helicopter. Because the horizon is affected by such environmental factors as vibration, temperature and so on while the helicopter is in working process, its failure rate is always high. Therefore, it is of great importance to achieve the key components'effective failure prognostics to discover the failure symptom as early and to prevent the occurrence of accidents.Research indicates that environment stress course such as vibration, temperature is the direct external factor. It causes the performance of horizon's key components degenerating or even invaliding. The fault prognostics can be achieved effectively by analysis of time stress. Therefore, the mechanism and rule that time stress induces the failure of helicopter horizon are systematically analyzed. The fault prognostics method based on time stress analysis for helicopter horizon is deeply investigated.The main contents of the research are as follows:1. The mechanism that time stress induces the horizon's faults is analyzed and a relative model is built.Firstly, the mechanism that faults are induced by time stress is analyzed in detail. Secondly, a dynamic relation description model between time stress and damage is built based on Generalized Stochastic Petri Nets (GSPN). Then the evolution relationship between time stress and component's damage is got.2. The time stress data feature extraction and calculating method of damage for the key components of the horizon is studied.Based upon the improved consumption monitoring methodology (LCM), the time stress data grade analysis and feature extraction method for the static converter are studied. Then, based on hot carrier degradation (HCD) model, the MOSFET's damage is calculated and the time stress is transformed into information of components'damage.3. The fault prognostics method of helicopter horizon's key components is studied based on damage information.To achieve fault prognostics for the horizon's key components, the overall mentality of horizon key component's failure prognostics is given based on the damage information. Firstly, the current damage information is used to carry out the failure prognostics. Then, considering the history trend of the prognostics result, a fault prognostics method is put forward based on damage information's Auto-regression Moving Average (ARMA) model. The experimental result shows that this method can result in accurate fault prognostics for the horizon.4. A fault prognostics system is designed and fault prognostics technology based on time stress is validated.In order to evaluate the efficiency of fault prognostics technology, a fault prognostics system for static converter of the horizon is built and implemented. Then, some experiment of time stress is executed on the static converter. According to the test results, the fault prognostics technology in this paper have been proved to be successful. It provides an effective and feasible way for the fault prognostics of the helicopter horizon's key components in the actual application.