Reliability analysis method of the uncertain system based on fuzzy GO methodology and its application in electro-hydrostatic actuator

The Goal-Oriented (GO) methodology is a success-oriented method for system reliability analysis. However, it is not suitable to evaluate the reliability of uncertain system caused by the insufficient or fluctuated data, model uncertainty, new components, and other external factors. In our study, with the combination of fuzzy set theory and the GO model, the triangular fuzzy number and the extended principle are introduced to quantify the fuzzy uncertainties of input and output state probability respectively. Hence, a new reliability analysis method of fuzzy GO methodology for the uncertain system is proposed. It serves to obtain the membership function of the intuitionistic fuzzy state probability and the fuzzy confidence interval by using the parameter programming for system reliability analysis. As a typical small sample complex electromechanical system, the reliability analysis of electro-hydrostatic actuator (EHA) has the characteristic of fuzzy uncertainty. Using EHA as the research object, the reliability analysis is conducted by the GO methodology, the fuzzy FTA method, and the fuzzy GO methodology respectively. The comparison results of the three methodologies show that the fuzzy GO methodology is an effective and a promising method, which is a reasonable and meaningful extension of the GO methodology. It can be used as a new reliability analysis method for the complex uncertain multi-state systems.