Fault diagnosis of dynamical systems using recurrent fuzzy systems with application to an electrohydraulic servo axis

This paper presents a novel approach for fault isolation based on discrete-time recurrent fuzzy systems (DTRFS) extending the well-known static fuzzy systems for fault isolation. The DTRFS additionally allows for the isolation of faults causing dynamic residuals and the isolation of multiple subsequently occurring faults. Due to the flexibility of the DTRFS, multiplicative as well as additive faults can be handled. The approach is applied to an electrohydraulic servo axis with a duplex valve system. Experimental results at the testbed underline the effectiveness and applicability of the approach and show the enhanced performance compared to static fuzzy systems and state automata.