Reliability Research On Electro Hydrostatic Actuator Based On GO Methodology

With.the rapid development of aviation science and technology, fly-by-wire flight control system comes into being. Power is transmitted from the second energy agency to implementing agencies by way of wire transmission. Fly-by-wire flight control systems reduce the weight of the aircraft greatly and have been highly concerned by aviation engineering. In current airborne actuation systems using fly-by-wire transmission, Electro Hydrostatic Actuator (EHA) has become a hot topic because of small size, big power and flexible features. EHA is a complex mechanics-electro-hydraulic integration typical control system. New integration actuation technology, EHA as its typical representation, is regarded as one of the five key technologies in future aircraft. Airborne actuation system is critical flight control subsystem to achieve the flight attitude and flight path control, and its performance will directly affect the aircraft flying qualities. The important content of the aircraft design is to ensure the reliability and security of airborne actuation system. Therefore, it is very important to research the reliability of EHA.The reliability analysis of EHA based on GO methodology is researched in this paper. The specific research contents and research results are as follows:(1) Distribution and estimation of the EHA reliability are described in details. The reliability parameters of component parts in EHA, according to experts grading method, provide a guarantee for the correctness of the following data.(2) The reliability quantitative analysis of EHA is studied based on GO methodology. Analytical procedure is presented in details.GO graph model is constructed according to the schematics of EHA. Probabilistic analysis method is used for GO operation, and the reliability result of EHA is obtained. The results of GO methodology and FTA methodology are compared in order to verify the correctness.(3) Focus on the reliability enhancement problem of complex mechanics-electronics-hydraulics-control integration EHA product, the multi-component redundancy method based on GO methodology is studied in this paper. The GO drawing and GO operation of multi-component redundancy parameters EHA are completed. The reliability calculation formula of a multi-component redundancy EHA is derived. The design theory of high reliability EHA is obtained. The new idea of GO method applied to EHA redundancy design is provided.(4) By compared the redundant designs between EHA with redundant components and EHA without redundant components, it is showed that EHA with redundant components can simplify the connection, reduce weight and have a positive effect to improve overall reliability. MATLAB/Simulink system is applied for simulation analysis of tri-redundant EHA to get some conclusions.The research results indicate that GO methodology is feasible for EHA reliability systematic analysis and design, and the analysis result is correct. The reliability analysis and design methodology based on GO methodology is systematic, because this method can get high reliability EHA by increasing component redundancy. This method has the advantage of accurate computations, and rapid obtaining the optimal redundancy design parameters. Simulation results show that tri-redundant EHA can meet the basic design requirements.