Sliding mode control technique is one of the well-recognized non-linear control methods. This method has an advantage like robustness against uncertainties. However, chattering phenomenon constraints the performance of closed loop system. To increase its efficiency, a fuzzy compensator is used along with this method. The fuzzy compensator weights are updated by using adaptive rules. The adaptation rate acts as a controlling coefficient. Therefore, the bigger amount of it increases the adaptation speed of weights which leads to the improvement of closed loop system performance. As a result, the probability of instability of closed loop system increases, too. In this study, it has been proposed to use a parallel fuzzy system along with the main fuzzy system in order to control its weights' adaptation. Moreover, a non-linear model of the electro-hydraulic system has been introduced as a case study. Finally, the performance of closed loop system and the efficiency of the proposed methods have been investigated by using numerical simulations.

Keywords: Sliding mode control, fuzzy compensator, parallel fuzzy system, adaptation rule, electro-hydraulic system

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