scholarly journals Robust Adaptive Fuzzy Control via State-Dependent Function for Nonlinear Stochastic Large-Scale Systems Subject to Dead Zones

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Chang-Qi Zhu ◽  
Lei Liu
Keyword(s):  
Fuzzy Control ◽  
Large Scale ◽  
Dead Zone ◽  
Adaptive Fuzzy Control ◽  
Closed Loop System ◽  
Large Scale Systems ◽  
Adaptive Fuzzy ◽  
State Dependent ◽  
Control Scheme ◽  
Robust Adaptive

This paper concentrates on the adaptive fuzzy control problem for stochastic nonlinear large-scale systems with constraints and unknown dead zones. By introducing the state-dependent function, the constrained closed-loop system is transformed into a brand-new system without constraints, which can realize the same control objective. Then, fuzzy logic systems (FLSs) are used to identify the unknown nonlinear functions, the dead zone inverse technique is utilized to compensate for the dead zone effect, and a robust adaptive fuzzy control scheme is developed under the backstepping frame. Based on the Lyapunov stability theory, it is proved ultimately that all signals in the closed-loop system are bounded and the tracking errors converge to a small neighborhood of the origin. Finally, an example based on an actual system is given to verify the effectiveness of the proposed control scheme.

scholarly journals Robust Adaptive Fuzzy Control for a Class of Uncertain MIMO Nonlinear Systems with Input Saturation

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Shenglin Wen ◽  
Ye Yan
Keyword(s):  
Nonlinear Systems ◽  
Fuzzy Control ◽  
Adaptive Fuzzy Control ◽  
Design Parameters ◽  
Tracking Errors ◽  
External Disturbances ◽  
Mimo Nonlinear Systems ◽  
Adaptive Fuzzy ◽  
Control Scheme ◽  
Robust Adaptive

This paper studies the robust adaptive fuzzy control design problem for a class of uncertain multiple-input and multiple-output (MIMO) nonlinear systems in the presence of actuator amplitude and rate saturation. In the control scheme, fuzzy logic systems are used to approximate unknown nonlinear systems. To compensate the effect of input saturations, an auxiliary system is constructed and the actuator saturations then can be augmented into the controller. The modified tracking error is introduced and used in fuzzy parameter update laws. Furthermore, in order to deal with fuzzy approximation errors for unknown nonlinear systems and external disturbances, a robust compensation control is designed. It is proved that the closed-loop system obtainsH∞tracking performance through Lyapunov analysis. Steady and transient modified tracking errors are analyzed and the bound of modified tracking errors can be adjusted by tuning certain design parameters. The proposed control scheme is applicable to uncertain nonlinear systems not only with actuator amplitude saturation, but also with actuator amplitude and rate saturation. Detailed simulation results of a rigid body satellite attitude control system in the presence of parametric uncertainties, external disturbances, and control input constraints have been presented to illustrate the effectiveness of the proposed control scheme.

Locomotion control of a hydraulically actuated hexapod robot by robust adaptive fuzzy control and dead-zone compensation

Robotica ◽  
2006 ◽  
Vol 25 (3) ◽  
pp. 269-281 ◽  
Author(s):  
Ranjit Kumar Barai ◽  
Kenzo Nonami
Keyword(s):  
Fuzzy Control ◽  
Dead Zone ◽  
Tracking Error ◽  
Adaptive Fuzzy Control ◽  
Control Technique ◽  
Joint Control ◽  
Locomotion Control ◽  
Adaptive Fuzzy ◽  
Hydraulically Actuated ◽  
Robust Adaptive

SUMMARYThis investigation presents locomotion control of a hydraulically actuated six-legged humanitarian demining robot by robust adaptive fuzzy control in conjunction with the dead zone compensation technique within independent joint control framework. For proper locomotion of the demining robot, accurate tracking of the desired joint trajectory is very important. However, high degree of nonlinearity, the uncertainties due to changing hydraulic properties, and delay due to the flow of oil and dead zone of the proportional electromagnetic control valve results into an inaccurate plant model for the hydraulically actuated robotic joints. Consequently, model-based classical control techniques result into a large tracking error. Therefore, adaptive fuzzy control technique, being a model independent control paradigm for complex and uncertain systems, is a good choice for such systems. In this work, a hydraulic dead zone compensated robust adaptive fuzzy control law has been proposed for locomotion control of hydraulically actuated hexapod demining robot. The experimental results exhibit a fairly accurate trajectory tracking of the leg joints and, consequently, very stable locomotion of the walking robot.

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