Adaptive fuzzy tracking control for a class of uncertain MIMO nonlinear systems using disturbance observer

• Published in: Science China. Information sciences Vol. 57; no. 1; pp. 242 - 254
• Main Authors: Chen, Mou, Chen, WenHua, Wu, QinXian
• Format: Journal Article
• Language: English
• Published: Heidelberg Science China Press 2014; Springer Nature B.V
• Subjects: Adaptive control; Approximation; Closed loops; Computer Science; Disturbance observers; Disturbances; Dynamical systems; Fuzzy; Fuzzy control; Fuzzy logic; Fuzzy systems; Information Systems and Communication Service; Lyapunov方法; Mathematical analysis; MIMO (control systems); MIMO非线性系统; Nonlinear control; Nonlinear dynamics; Nonlinear systems; Research Paper; Singularities; Tracking control; Uncertainty; 干扰观测器; 扰动观测器; 模糊逻辑系统; 系统不确定性; 自适应; 跟踪控制; tracking control; fuzzy logic systems; MIMO nonlinear system; disturbance observer; input saturation
• ISSN: 1674-733X; 1869-1919
• DOI: 10.1007/s11432-012-4695-3

In this paper, the adaptive fuzzy tracking control is proposed for a class of multi-input and multi- output（MIMO） nonlinear systems in the presence of system uncertainties, unknown non-symmetric input satu- ration and external disturbances. Fuzzy logic systems（FLS） are used to approximate the system uncertainty of MIMO nonlinear systems. Then, the compound disturbance containing the approximation error and the time- varying external disturbance that cannot be directly measured are estimated via a disturbance observer. By appropriately choosing the gain matrix, the disturbance observer can approximate the compound disturbance well and the estimate error converges to a compact set. This control strategy is further extended to develop adaptive fuzzy tracking control for MIMO nonlinear systems by coping with practical issues in engineering ap- plications, in particular unknown non-symmetric input saturation and control singularity. Within this setting, the disturbance observer technique is combined with the FLS approximation technique to compensate for the efects of unknown input saturation and control singularity. Lyapunov approach based analysis shows that semi-global uniform boundedness of the closed-loop signals is guaranteed under the proposed tracking control techniques. Numerical simulation results are presented to illustrate the efectiveness of the proposed tracking control schemes.