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Adaptive Fuzzy Control Of Nonlinear Systems With Unknown Virtual Control Coefficients

Posted on:2020-05-21Degree:MasterType:Thesis
Country:ChinaCandidate:F WangFull Text:PDF
GTID:2438330590985573Subject:System theory
Abstract/Summary:PDF Full Text Request
This thesis mainly addresses a class of adaptive fuzzy control problems for single-input single-output nonlinear systems with unmeasurable state variables and unknown virtual control coefficients.Based on Adaptive fuzzy control method,Backstepping technique and Lyapunov stability theory,a robust observer design scheme is proposed,furthermore,an observer-based adaptive fuzzy output feedback control strategy is developed.The closed-loop stability analysis is also given.The specific research content is listed as follows:1.Consider adaptive fuzzy output feedback control for a class of strict-feedback nonlinear systems with the unmeasurable state variables,unknown virtual control coefficients.By using the convex combination method,the difficulty caused by the unknown virtual control coefficients for observer design is overcome.A robust fuzzy observer is constructed,furthermore,an observer-based adaptive fuzzy output feedback control scheme is proposed by Backstepping.The closed-loop stability is provided,it is shown that all the closed-loop signals are bounded and the systems output fellows the given reference signal well.At last,numerical simulation is utilized to test the effectiveness of the suggested control scheme.2.Consider adaptive fuzzy output feedback control for a class of non-strict feedback nonlinear systems.A robust fuzzy observer design scheme is presented by fuzzy control method and Backstepping technique.During the procedure of controller design,the Young inequality and the property of the norm of basis vector functions of fuzzy logic systems are used to overcome the difficulty caused by the structure of non-strict feedback.Thus,under the frame of adaptive fuzzy control theory Backstepping is extended to non-strict feedback nonlinear systems for control design.Finally,the stability analysis of the closed-loop system is carried out,which proves that the closed-loop system signal remains bounded,and the system output can track a given reference signal well.The effectiveness of the proposed control scheme is verified by numerical simulation.3.The control design is considered for nonlinear systems with dead zone input.The input dead zone is decomposed into the sum of two parts,which is a linear part and a bounded nonlinear part.The corresponding observer and controller designschemes are given next.Finally,an example simulation demonstrates the effectiveness of the theoretical results.
Keywords/Search Tags:dead zone input, virtual control coefficient, Backstepping design method, adaptive fuzzy control, nonlinear system
PDF Full Text Request
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