Robust Output Feedback Control of a Class of Nonlinear Systems Using a Disturbance Observer

• Published in: IEEE transactions on control systems technology Vol. 19; no. 2; pp. 256 - 268
• Main Authors: Zi-Jiang Yang, Hara, S, Kanae, S, Wada, K
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.03.2011; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Backstepping; Backstepping design; Computer science; control theory; systems; Control system analysis; Control system synthesis; Control systems; Control theory. Systems; disturbance observer (DOB); Disturbance observers; Disturbances; Dynamical systems; Error correction; Exact sciences and technology; feedback linearizable nonlinear system; high-gain observer (HGOB); input-to-state stability (ISS); Linear control; Modelling and identification; Nonlinear control systems; nonlinear damping term; Nonlinear dynamics; Nonlinear systems; Nonlinearity; Observers; Output feedback; Robust control; State estimation; System theory; Uncertainty; High gain observer; Non linear control; Feedback regulation; Control synthesis; Backstepping design; Linear control; Modeling; Uncertain system; nonlinear damping term; System identification; feedback linearizable nonlinear system; State estimation; high-gain observer (HGOB); Output signal; Non linear system; Recursive algorithm; Backstepping control; Closed feedback; Robust control; Input to state stability; input-to-state stability (ISS); Model reference adaptive control systems; disturbance observer (DOB); Output feedback; Lyapunov function; Magnetic levitation; Magnetic suspension
• ISSN: 1063-6536; 1558-0865
• DOI: 10.1109/TCST.2010.2049998

This paper considers the output-tracking control problem of feedback linearizable nonlinear systems in the presence of external disturbances and modeling errors. A robust output feedback nonlinear controller is designed to achieve excellent output-tracking performance. By exploiting the cascade features of backstepping design, a simple disturbance observer (DOB) is proposed to suppress the effects of the uncertainties, and a high-gain observer (HGOB) is applied to estimate the unmeasureable states of the system. Although the DOB-based controllers are usually designed according to linear control theory, in this study, strict analysis of the nonlinear control system is given. Experimental results on a magnetic levitation system are provided to support the theoretical results and to verify the advantages of the proposed controller.