Adaptive controller of nonlinear systems with unknown control directions and unknown input powers. (15th September 2020)

• Record Type: Journal Article
• Authors: Guo, Tiantian; Liu, Yungang; Man, Yongchao
• Is Part Of: International journal of robust and nonlinear control. Volume 30:Number 17(2020)
• Page Start: 7670
• Page End: 7689
• Publication Date: 2020-09-15
• Subjects: adaptive controller -- global stabilization -- nonlinear systems -- switching scheme -- unknown control directions -- unknown input powers; Automatic control -- Periodicals; Control theory -- Periodicals; Nonlinear systems -- Periodicals; 629.836
• DOI: 10.1002/rnc.5213
• Languages: English
• ISSNs: 1049-8923

Abstract

Summary: This article is devoted to global adaptive stabilization for a class of uncertain nonlinear systems. Notably, the systems under investigation admit unknown control directions and unknown input powers, and particularly the latter, which are a new type of system uncertainties, largely challenge the feasibility of continuous feedbacks. This spurs us to pursue a switching adaptive feedback which is actual a discontinuous one with high feedback capability. To solve the control problem, a parameterized controller in a specified form is first introduced, which can globally stabilize the system once the design parameter involved belongs to a certain set. However, the controller cannot directly be implemented since the set depends heavily on the unknown input powers. To make the parameterized controller implementable, a new switching strategy is delicately proposed, which can instantly update the parameters of the controller to compensate the serious system uncertainties. It turns out that the parameterized controller with switching updating mechanism guarantees that all the signals of the closed‐loop system are globally bounded and ultimately converge to zero. Simulation examples demonstrate the effectiveness of the proposed design scheme.