A powerful output‐feedback controller for uncertain nonlinear systems. (29th December 2017)

• Record Type: Journal Article
• Authors: Man, Yongchao; Liu, Yungang
• Is Part Of: International journal of robust and nonlinear control. Volume 28:Number 6(2018)
• Page Start: 2264
• Page End: 2275
• Publication Date: 2017-12-29
• Subjects: nonlinear systems -- output‐feedback controller -- switching logic -- unknown control direction -- unmeasured state–dependent growth; Automatic control -- Periodicals; Control theory -- Periodicals; Nonlinear systems -- Periodicals; 629.836
• DOI: 10.1002/rnc.4014
• Languages: English
• ISSNs: 1049-8923

Abstract

Summary: System nonlinearities, immeasurableness, and uncertainties (especially their coupling/coexistence) have constantly challenged the control design, which requires the controller to be powerful enough to counteract the resulting negative effects. In this paper, a global adaptive output‐feedback controller is designed for uncertain nonlinear systems. The proposed controller is of switching type, in which the design parameters are online adjusted on the basis of a switching logic in a recursive manner. This makes the controller powerful enough to compensate the system unknowns and dominate the system nonlinearities and therefore be applicable to a rather wide range of systems. Remarkably, our strategy allows the coexistence of an unknown control direction and unmeasured state–dependent growth but which are substantially excluded in the related literature. An example of the single‐link robot arm system is provided to illustrate the effectiveness of the proposed controller.