A novel fuzzy extended state observer

In designing the extended state observer (ESO), one of the most challenging issues is its performance improvement. In this paper, a simple fuzzy system is proposed to improve the performance of ESO and changes this observer into fuzzy extended state observer (FESO). This FESO is an intelligent linear form of the ESO. The fuzzy system, which is applied to tune the observer gains in an intelligent manner, directs the observer to deliver an appropriate estimation performance. To design this fuzzy system, a simple input-output form is applied to reduce the number of fuzzy rules. The linear form of FESO simplifies the convergence analysis of this observer, which is analyzed through a Lyapunov function. The performance of FESO in the fields of fault diagnosis and active disturbance rejection control (ADRC) are shown by simulation examples and compared with traditional forms of ESO. In this paper, it is revealed that this new proposed ESO embodies advantages of the simple linear structure and provides a good performance, confirmed by its results. (C) 2019 ISA. Published by Elsevier Ltd. All rights reserved.