Harmonic Disturbance Observer for Nonlinear Systems

2003 ◽  
Vol 125 (1) ◽  
pp. 114-117 ◽  
Author(s):  
Wen-Hua Chen
Keyword(s):  
Nonlinear Systems ◽  
Disturbance Observer ◽  
Disturbance Attenuation ◽  
Nonlinear Controller ◽  
Gain Function ◽  
Nonlinear Gain ◽  
Nonlinear Disturbance Observer ◽  
Systematic Procedure ◽  
Nonlinear Disturbance

A nonlinear harmonic disturbance observer for nonlinear systems subject to harmonics is designed and stability of the proposed observer is established using passivity approach. A systematic procedure to choose the nonlinear gain function in the observer is proposed. The proposed nonlinear disturbance observer can be integrated with a linear/nonlinear controller to improve its disturbance attenuation ability for nonlinear systems under harmonics.

scholarly journals Robust Control of Uncertain Nonlinear Systems: A Nonlinear DOBC Approach

2016 ◽  
Vol 138 (7) ◽  
Author(s):  
Wen-Hua Chen ◽  
Jun Yang ◽  
Zhenhua Zhao
Keyword(s):  
Robust Control ◽  
Nonlinear Systems ◽  
Disturbance Observer ◽  
External Disturbance ◽  
Uncertain Nonlinear Systems ◽  
Nonlinear Controller ◽  
Nonlinear Disturbance Observer ◽  
Spring System ◽  
Mass Spring ◽  
Distinct Features

This paper advocates disturbance observer-based control (DOBC) for uncertain nonlinear systems. Within this framework, a nonlinear controller is designed based on the nominal model in the absence of disturbance and uncertainty where the main design specifications are to stabilize the system and achieve good tracking performance. Then, a nonlinear disturbance observer is designed to not only estimate external disturbance but also system uncertainty/unmodeled dynamics. With described uncertainty, rigorous stability analysis of the closed-loop system under the composite controller is established in this paper. Finally, the robust control problems of a missile roll stabilization and a mass spring system are addressed to illustrative the distinct features of the nonlinear DOBC approach.

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