Adaptive dynamic surface control using disturbance observer for nonlinear systems with input saturation and output constraints

ABSTRACT

An adaptive dynamic surface control (DSC) approach using fuzzy approximation and nonlinear disturbance observer (NDO) for uncertain nonlinear systems in the presence of input saturation, output constraint and unknown external disturbances is proposed in this paper. The issue of input saturation is addressed by introducing a lower bound assumption on the approximation function of saturation. The output constraint is handled by introducing an appropriate barried Lyapunov function. The nonlinear disturbance observer (NDO) is employed to estimate the unknown unmatched disturbances. It is manifested that the ultimately bounded convergence of all the variables in the closed-loop system is guaranteed and the tracking error can be made farely small by tuning the design parameters. Finally, two simulation examples illustrate the effectiveness and feasibility of the proposed approach.

KEYWORDS:

• Fuzzy logic systems
• dynamic surface control
• nonlinear disturbance observer
• pure-feedback systems

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [grant numbers 61773207 and 61473151]; the Natural Science Fund for Distinguished Young Scholars of Jiangsu Province [grant number BK20150034]; and Major Project of Scientific and Technological Innovation in Hubei [grant number 2018ABA076].

Notes on contributors

Wei Liu

Wei Liu received M.S. degree in power electronics and power drive from Anhui University of Technology,Ma'anshan, Anhui, China, in 2009. He is also a Lecturer in School of Electronic Engineering, Huai'an Vocational College of Information Technology. He is currently working towards the Ph.D. degree with School of Automation, Nanjing University of Science and Technology. His research interests include multi-agent systems and nonlinear adaptive control.

Qian Ma

Qian Ma received B.S. from Jiangsu University of Science and Technology in 2005, M.S. and Ph.D. from Nanjing University of Science and Technology, in 2007 and 2013. Since June 2013, she has joined the School of Automation at Nanjing University of Science and Technology, where she is currently a Professor. Her current research interests include time-delay systems, stability theory, and cooperative control.

Guopeng Zhou

Guopeng Zhou received B.S. from Hubei University in 1994, M.S. and Ph.D. from South China University of Technology in 2007 and 2013, respectively. He is a professor in Institute of Engineering and Technology, Hubei University of Science and Technology. His research interests include system stability analysis and control synthesis, ordinary differential equation.

Jianrong Zhao

Jianrong Zhao received the B.S. degree in statistics from the School of Mathematical Sciences, Qufu Normal University, Qufu, China, in 2013 and the M.S. degree in operational research and control theory from the Institute of Automation, Qufu Normal University, Qufu, China, in 2016. Now he is currently pursuing the Ph.D. degree in control science and engineering with Nanjing University of Science and Technology, Nanjing, China. His research interests include switched systems, sampled-data control systems, and nonlinear systems.