Enhanced Adaptive Self-Organizing Fuzzy Sliding-Mode Controller for Active Suspension Systems

Abstract

A self-organizing fuzzy controller (SOFC) is proposed to control engineering applications. However, its stability is difficult to demonstrate. Therefore, the parameters of the SOFC must be carefully chosen to ensure that the system controlled by the SOFC can operate stably. To overcome the problem, this study developed an enhanced adaptive self-organizing fuzzy sliding-mode controller (EASFSC) for active suspension systems. Rather than using the output error and the error change of the system, the EASFSC uses a sliding surface and its differential as the input variables of a fuzzy logic controller (FLC) in the SOFC to generate a control input through fuzzy operation. It also applies an adaptive law to modify the fuzzy consequent parameter of the FLC in the SOFC to improve the stability of the system. The stability of the EASFSC was proven using the Lyapunov stability theorem. The EASFSC eliminates the problem of an SOFC implementation in determining the stability of the system and overcomes the difficulty of finding appropriate membership functions and fuzzy rules for designing an FLC. To confirm the applicability of the EASFSC, this study used the EASFSC to manipulate an active suspension system to improve its control performance. Experimental results showed that the EASFSC achieved better control performance than the SOFC for active suspension control.