Fuzzy adaptive control enhancement for non-affine systems with unknown control gain sign

2015 ◽  
Author(s):  
Khatir Khettab ◽  
Yassine Bensafia ◽  
Samir Ladaci
Keyword(s):  
Adaptive Control ◽  
Fuzzy Adaptive Control ◽  
Affine Systems ◽  
Control Gain ◽  
Unknown Control ◽  
Fuzzy Adaptive

scholarly journals Fuzzy Adaptive Control for Fractional Nonlinear Systems with External Disturbances and Unknown Control Directions

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Yeguo Sun ◽  
Yihong Liu ◽  
Ling Li
Keyword(s):  
Adaptive Control ◽  
Fractional Order ◽  
Direct Method ◽  
Triangular Matrix ◽  
Fuzzy Logic Systems ◽  
External Disturbances ◽  
Fuzzy Adaptive Control ◽  
Unknown Control Directions ◽  
Unknown Control ◽  
Fuzzy Adaptive

In this paper, the problem of fuzzy adaptive control of unknown nonlinear fractional-order systems with external disturbances and unknown control directions is studied. We exploit a decomposition of the control gain matrix into a symmetric positive-definite matrix, a diagonal matrix with diagonal entries + 1 or 1 , and a unity upper triangular matrix. Fuzzy logic systems are used for estimating the unknown nonlinear functions. Based on the fractional Lyapunov direct method and some proposed lemmas, a novel fuzzy adaptive controller is designed. The proposed method can guarantee that all the signals in the closed-loop systems remain bounded and the tracking errors converge to an arbitrary small region of the origin. In addition, for updating the parameters of the fuzzy system, fractional-order adaptations laws are proposed. Lastly, an illustrative example is given to demonstrate the effectiveness of the proposed results.

scholarly journals Fuzzy Adaptive Prescribed Performance Control for Uncertain Horizontal Platform System with Unknown Control Gain

2015 ◽  
Vol 2015 ◽  
pp. 1-8
Author(s):  
Wei Xiang ◽  
Yeguo Sun ◽  
Chunzhi Yang
Keyword(s):  
Control Method ◽  
Adaptive Controller ◽  
Performance Bounds ◽  
Constrained System ◽  
Prescribed Performance ◽  
Performance Technique ◽  
Control Gain ◽  
Unknown Control ◽  
Platform System ◽  
Fuzzy Adaptive

This paper proposes a fuzzy adaptive control method for uncertain horizontal platform system with unknown control gain, which is capable of guaranteeing the prescribed performance bounds. An error transformation is introduced to transform the original constrained system into an equivalent unconstrained one. Then, based on the error transformation technique and the predefined performance technique, a fuzzy adaptive controller is designed for the unconstrained system. It is shown that all the variables of the resulting closed-loop system are bounded. Finally, an illustrative example is given to demonstrate the effectiveness and usefulness of the proposed method.

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