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Adaptive Practical Output Tracking Control For Uncertain Nonlinear Systems

Posted on:2006-09-19Degree:DoctorType:Dissertation
Country:ChinaCandidate:Q D WangFull Text:PDF
GTID:1118360185977717Subject:Control theory and control engineering
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The nonlinear servomechanism problem or the problem of nonlinear output regulation is to design a feedback controller such that the output of a nonlinear system asymptotically tracks prescribed reference signals and rejects input disturbances, while maintaining internal stability of the close-loop system. The problem has been extensively investigated by a number of researchers and many important results have been made over the past decade. In this dissertation, the output tacking control problems of some class of nonlinear systems are investigated. The main work is generalized as follows:For a class of feedback linearizable nonlinear systems with parameters uncertainty and nonlinear function uncertainty, the robust adaptive output tracking control problem is dealt with. By means of the backstepping method, a robust adaptive state feedback controller is designed. The output of the system can track a prescribed reference signal. Under the assumption that the reference signal and its derivative are bounded, the global output tracking is obtained. Moreover all the signals in the closed-loop systems are globally uniformly bounded.Focus is laid on the adaptive practical output tracking control problem of a class of nonlinear systems with high-order lower-triangular and uncontrollable unstable linearization. The asymptotic output tracking is usually not possible because the linearized system has uncontrollable modes whose eigenvalues are on the right half plane. Using the modified adaptive adding a power integrator technique as a basic tool, a new smooth adaptive state feedback controller is designed. The global practical output tracking is achieved and all the signals of the closed-loop systems are globally...
Keywords/Search Tags:nonlinear systems, adaptive control, practical output tracking state feedback, adding a power integrator, uncontrollable unstable linearization, nonlinear parameterization
PDF Full Text Request
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