Title: A review on the uncertainty and disturbance estimator, its applications and extensions

Authors: Andre Shigueo Yamashita

Addresses: Department of Electrical and Computer Engineering, Illinois Institute of Technology, 3301 South Dearborn, Siegel Hall Room 221A, Chicago, IL 60616, USA

Abstract: Uncertainty and disturbance estimator is a control strategy that cancels model uncertainty and external disturbances, allowing for the straightforward control of complex nonlinear, time delayed systems subject to disturbances. The UDE strategy has been applied successfully in the extension of control strategies initially designed for systems without disturbances (input output linearisation, feedback linearisation, sliding mode control). The main idea behind the controller is that a filter of appropriate bandwidth can estimate an unknown signal accurately enough, so the estimation can be utilised in the control design to cancel system uncertainties and external disturbances. This survey summarises the methodology and characteristics of UDE reported in the literature. The UDE strategy and three main applications of UDE in other control strategies are compared in two case studies, first a linear system with fast varying disturbances and a nonlinear continuous stirred tank reactor. The results show that UDE yields fast and accurate state tracking on one hand and large control actions in the other. Finally, some considerations about future applications in multi-variable systems are presented.

Keywords: uncertainty disturbance estimator; nonlinear systems with disturbances; fast varying disturbances; process control; robust control.

DOI: 10.1504/IJAAC.2017.087053

International Journal of Automation and Control, 2017 Vol.11 No.4, pp.384 - 410

Received: 04 Aug 2016
Accepted: 02 Dec 2016

Published online: 05 Oct 2017 *

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