Fault Detection Based on Type 2 Fuzzy system for Single-Rod Electrohydraulic Actuator

Abstract

Electro-hydraulic systems with regards to the their specific features and applications among other industrial systems including mechanical, electrical and pneumatic systems, have been widely taken into consideration by the scientists and researchers. Due to the fact that the electro-hydraulic system is inherently a nonlinear system, has some problems such as signals saturation, nonlinear efficiency, uncertainties caused by the compressibility, internal and external leakages, dead band of the flow around the zero point and the adhesion and friction. In this paper fault detection issue in an electro-hydraulic system based on the type-2 fuzzy system has been considered. One of the most important theories proposed for the identification and control of the nonlinear systems is the fuzzy systems theory. Therefore, in this study due to the nonlinearity of the electro-hydraulic system, the use of type-2 fuzzy system of fuzzy systems theory is proposed. Type-2 fuzzy systems has a better performance capability than type-1 fuzzy systems. In this paper residual signal generation method has been used for fault detection. Using type-2 fuzzy theory the upper and lower bounds are estimated for the output, and in case of deviating the output graph of the system under control from this estimated band, the occurrence of fault can be detected. Eventually, the simulation results on the system under study determine the capability of the proposed method.