Search

Summary: This paper discusses the adaptive control problem for a class of nonlinear systems with polynomial growing conditions. By introducing a Lyapunov function which carries the quadratic terms and higher‐order terms of the transformed variables and constructing an appropriate dynamic gain, a new control strategy is presented to design an adaptive controller using only one parameter estimation. Compared with the existing results, the presented method avoids the over‐parameterization and significantly simplifies the control design. A modified version of the method which adopts no parameter estimation is also provided. It shows that all the signals of the closed‐loop system are bounded and the solution of the original system converges to zero. A simulation example is given to show the validness of the method. [ABSTRACT FROM AUTHOR]

In this work, the tracking control problem of nonlinear system which contains unknown parameters, multiple state delays, external disturbances and the dead-zone input is studied. By introducing a dynamic gain-based adaptive control strategy and employing a new Lyapunov–Krasovskii (L–K) functional, we construct an adaptive tracking controller to ensure the boundedness of all the states and guarantee the tracking error small enough. Two examples are given to verify the correctness of the control theory. [ABSTRACT FROM AUTHOR]

Summary: This article studies the robust adaptive tracking control problem of nontriangular nonlinear systems that are affected by multiple state delays rather than the input‐delay. Different from the related studies, the considered systems involve input dead‐zone and various uncertainties arising in the control coefficients, structure parameters, time delays, and disturbances. A new adaptive control strategy is presented by introducing a dynamic‐gain‐based Lyapunov‐Krasovskii functional and by generalizing the tuning function method in the framework of time‐delay system theory. All the states of the closed‐loop system are bounded and the tracking error can be adjusted sufficiently small. In the simulation, the delayed chemical system is studied to demonstrate the validity of the strategy. [ABSTRACT FROM AUTHOR]

In this paper, the robust adaptive tracking control problem is investigated for nonlinear time-delay systems with changing system powers. Different from the existing results, the discussed system has complicated nonlinear growing conditions and various uncertainties including the control coefficients, parameters, and external disturbances. By introducing a new robust adaptive control method, a dynamic-gain based adaptive tracking controller is constructed to guarantee the boundedness of the closed-loop systems. Besides, the tracking error can be adjusted with a satisfied precision. Finally, simulation examples are given to verify the proposed theory. [ABSTRACT FROM AUTHOR]

A decoupled adaptive control algorithm, namely the combined dynamic gain and adaptive homogeneous domination approach, is introduced to solve the global state feedback stabilization problem for a class of uncertain nonlinear systems. Compared with the conventional adaptive backstepping/tuning functions approach, the algorithm differs in the way of constructing the estimator and handling the nonlinear drifts, and allows the adaptive control law that is decoupled via a dynamic gain to be designed only by choosing some appropriate constants. The proposed adaptive controller guarantees that all the states of the closed-loop system are globally bounded and the system solutions converge to zero asymptotically. Both physical and academic examples are provided to demonstrate the validness of the theory. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This paper studies the universal adaptive control for a class of stochastic nonlinear time-delay systems, which involve odd rational powers, multiple time-varying delays and parameter uncertainties. Since many new obstacles that have not been encountered should be carefully dealt with, the adaptive control problem remains challenging. A universal controller which employs the dynamic gain and the adaptive control strategy is firstly constructed to ensure that all signals of the closed-loop systems are bounded almost surely and the states of the considered systems converge to the origin almost surely. By proposing an extended method, another universal adaptive controller which removes the dynamic gain and reduces the order of the controller is also designed. A single-link robot system is considered to verify the effectiveness of the developed theory. [ABSTRACT FROM AUTHOR]