Su Chen1, Dahai Li2, and Jing Wang1
1Department of Mechanical and Electrical Engineering, Henan Vocational College of Water Conservancy and Environment,
Zhengzhou, 450002 China
2School of Electronics and Electrical Engineering, Zhengzhou University of Science and Technology, Zhengzhou, 450064 China
Received: May 31, 2026
Accepted: July 15, 2026
Publication Date: August 05, 2026
Comparison of Tracking Errors for Four Control Methods.
Copyright The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are cited.
Download Citation: BibTeX | http://dx.doi.org/10.6180/jase.202611_34.004
Aiming at the nonlinear dynamic characteristics, parameter uncertainties, external complex disturbances, and inherent friction interference of multi-joint manipulator robots, in this work, a nonlinear disturbance observer (DO) is combined with an adaptive fuzzy neural network (AFNN) to form a new control strategy for manipulators. The dynamic model of the manipulator is formulated by considering various composite disturbances, including parametric uncertainties, unmodeled dynamics and external load interference. The developed nonlinear observer can achieve real-time observation and compensation for low-frequency lumped disturbances, thereby alleviating the operating pressure of the main control unit. The residual observation error and high-frequency unknown disturbances of the disturbance observer online are then approximated via an improved RBF fuzzy neural network (RBF-FNN). And adaptive learning laws of network weights are derived based on the Lyapunov stability criterion to realize self-adjustment of control parameters. In addition, the composite control strategy combining disturbance feed-forward compensation and fuzzy neural network adaptive feedback control effectively suppresses the chattering phenomenon existing in traditional sliding mode control and improves the trajectory tracking accuracy of the manipulator. Lyapunov stability criterion is adopted to rigorously demonstrate the stability of the overall closed-loop system. It is verified that both tracking errors and observation errors satisfy the uniform ultimate boundedness condition. Subsequently, comparative simulations are implemented on a two-link manipulator test platform. The results reveal that the presented AFNN-DO strategy outperforms conventional sliding mode control (SMC), standalone fuzzy neural network control and DO-based sliding mode control (DO-SMC) in response rapidity, tracking precision and disturbance rejection performance. The maximum position tracking error of each joint is reduced by 46.8% and 52.3% respectively, which verifies the feasibility and superiority of the proposed control method
Keywords: Manipulator robot; Disturbance observer; Adaptive fuzzy neural network; Trajectory tracking; Lyapunov stability; Lumped disturbance
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