Adaptive fuzzy funnel control for nonlinear systems with input deadzone and saturation

Abstract

This paper, for the first time, focuses on the problem of funnel control for strict-feedback systems with input deadzone and saturation, simultaneously. A new smooth function in non-affine form is firstly proposed to approximate the non-smooth input deadzone and saturation and transformed into an affine form by the mean-value theorem. The unknown nonlinear functions and external disturbances are estimated by fuzzy logic systems. An improved funnel error is given and embedded in the procedure of controller design. Based on the backstepping method, an adaptive fuzzy funnel controller is constructed, which guarantees that the output tracking error falls within a pre-set funnel and all the signals in the closed-loop system are semi-globally uniformly and ultimately bounded. Simulation results demonstrate the effectiveness of the developed controller.

Keywords:

• Nonlinear system
• funnel control
• deadzone
• saturation

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work is financially sponsored by Taishan Scholar Project of Shandong Province of China (2015162, 201812093) and the National Natural Science Foundation of China (61773072, 41702325).

Notes on contributors

Cungen Liu

Cungen Liu is an Associate Professor at Shandong Jianzhu University,Jinan, China. His research interest is theory and applications of robotics.

Huanqing Wang

Huanqing Wang is a visiting professor in Shandong Jianzhu University, Jinan, China. He has authored or co-authored over 50 papers in top international journals. His current research interests include adaptive backstepping control, fuzzy control, neural networks control, and stochastic nonlinear systems.

Xiaoping Liu

Xiaoping Liu joined the Department of Electrical Engineering at Lakehead University, Canada in 2001 and has been a visiting professor in Shandong Jianzhu University, Jinan, China. His research interests are nonlinear control systems, singular systems, and adaptive control. He is a member of the Professional Engineers of Ontario.

Yucheng Zhou

Yucheng Zhou is a Taishan scholar in Shandong Jianzhu University, Jinan, China, His research interest is control of complex system.