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Abstract: In this paper, we consider the adaptive stabilization problem for feedforward nonlinear systems with time delays. An adaptive stabilizer is proposed. Our stabilizer takes a nested saturation feedback, and a set of switching logics is designed to tune online the saturation levels in a piecewise constant or switching manner. It has been shown that under our proposed control, all closed-loop states are bounded and asymptotic regulation is achieved. [Copyright &y& Elsevier]

Abstract: In this paper, we propose a pseudo-decentralized adaptive control scheme for a class of large-scale feedforward nonlinear systems with unknown nonlinear effects within subsystems and unknown nonlinear interactions among subsystems. The local controller of each subsystem takes a nested saturation feedback, using the state of its own subsystem, and the saturation levels are tuned online in a switching manner via a set of switching logics, which requires some binary flag communication among subsystems. Global asymptotic regulation of the closed-loop states is achieved. [Copyright &y& Elsevier]

Abstract: A multiple model adaptive controller is proposed for nonlinear systems in parametric-strict-feedback form. By running in parallel multiple identification models and designing a suitable switching scheme, some models close to the real plant can be selected quickly, so that transient performance can be improved significantly. Global asymptotic stability of the closed-loop switching system is proved. A simulation example is given to demonstrate the effectiveness of the proposed multiple model adaptive controller. [Copyright &y& Elsevier]

Abstract: In this paper, we consider global adaptive output-feedback control of nonlinear systems in output-feedback form, with unknown parameters entering nonlinearly. Such unknown parameters are not required to lie in a known compact set. Our proposed adaptive output-feedback controller is a switching-type controller, in which the controller parameter is tuned in a switching manner via a switching logic. Global stability results of the closed-loop system have been proved. [Copyright &y& Elsevier]

In this paper, we investigate output synchronization problem of nonlinear systems that can be transformed into strict feedback form with unknown control direction. To this end, an augmented Laplacian potential function is introduced to construct local level distributed adaptive controllers such that outputs of networked agents can be synchronized while all other states maintain bounded. Moreover, tuning functions are designed to reduce the order of the parameter updater. In contrast to conventional adaptive backstepping procedure, both the parameter updating law and tuning function of the proposed scheme take advantage of information flow among networked agents and thus distributive in nature. It is proved that output synchronization of the entire network can be achieved by properly choosing Nussbaum functions, provided the information graph is undirected and connected. Furthermore, we also proposed a way to define a proper Nussbaum function. Simulation results are presented to verify the effectiveness of the proposed schemes. [ABSTRACT FROM AUTHOR]