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This work addresses the adaptive output feedback quantized control for a class of switched stochastic nonstrict‐feedback nonlinear time‐delay systems with input and output quantization and actuator saturation under arbitrary switching. A novel state observer including the quantized output signal and the saturated input signal is designed to estimate the unknown system states. Then, the command‐filtered backstepping method is introduced to avoid the "explosion of complexity" in the adaptive backstepping recursive design. Moreover, the design challenges from input and output quantization errors and actuator saturation are overcome by combining the auxiliary variable approach and some special techniques. Instead of the traditional quartic Lyapunov–Krasovskii functional, the common quadratic Lyapunov–Krasovskii functional is constructed to develop the adaptive quantized tracking control scheme for such systems. By means of the proposed common controller independent of switching signal, all closed‐loop signals are mean‐square semi‐globally uniformly ultimately bounded, while the tracking error will remain in a small neighborhood of the origin. Finally, stability analysis and simulation results are provided to show the effectiveness and performance of the proposed design methodology. [ABSTRACT FROM AUTHOR]

This paper addresses the adaptive tracking problem for a class of uncertain switched stochastic strict-feedback nonlinear systems with both sector-bounded quantization input and unknown time-varying delays under arbitrary switching. Major design difficulties for such systems, in which all the time-varying delays absolutely depend on the subsystem number, come from finding a common Lyapunov function (CLF) for all subsystems and dealing with the sector-bounded quantization error. The Lyapunov–Razumikhin method is employed to construct a suitable CLF for all subsystems and relax the restrictions on the time-varying delays. Moreover, some new techniques are presented to overcome the difficulty from the sector-bounded quantization error. With the application of backstepping technique, variable separation technique and fuzzy logic system approximation, a common adaptive tracking control scheme containing only one adaptive parameter is proposed for this class of systems. The derived quantized control scheme ensures that the tracking error remains in a small neighborhood of the origin via the appropriate adjustment of design parameters while all the signals in closed loop system are bounded in probability. Finally, two simulation examples are provided to illustrate the feasibility and applicability of the proposed control design. [ABSTRACT FROM AUTHOR]

The problem of output feedback adaptive tracking control is studied for a class of stochastic nonlinear time-delay systems in which the measured output and input signals are quantized by two sector-bounded quantizers respectively. An observer including the quantized input and output signals is designed to estimate the unknown system states, and the unknown system functions with less restrictions are dealt with by using the neural network’s (NN) approximation. By combining the backstepping technique and the Lyapunov–Krasovskii method, an observer-based adaptive neural quantized tracking control scheme is presented for this class of systems. The stability analysis indicates that the tracking error can converge to a small neighborhood of the origin while all closed-loop signals are 4-moment (or 2-moment) semi-globally uniformly ultimately bounded (SGUUB). Finally, two illustrative examples are provided to demonstrate the feasibility and effectiveness of the proposed design methodology. [ABSTRACT FROM AUTHOR]

This paper focuses on the problem of adaptive tracking control for a class of switched strict-feedback nonlinear systems with unknown time-varying delays and asymmetric saturation actuators under arbitrary switching. Especially, the considered time-varying delays absolutely depend on the subsystem number. The main technical difficulties lie in finding an appropriate common Lyapunov function (CLF) for all subsystems and designing a common adaptive control scheme in the presence of unknown time-varying delays and asymmetric saturation nonlinearities. Based on a novel combination of Lyapunov–Razumikhin method, dynamic surface control (DSC) technique, variable separation approach and neural network (NN) approximation, a simple quadratical CLF is constructed and a common adaptive control scheme involving only one adaptive parameter is developed. The proposed controller guarantees that all signals of closed-loop system are semi-globally uniformly ultimately bounded (SGUUB) while the tracking error converges to an adjustable neighborhood of the origin. Finally, the effectiveness of the design methodology is illustrated with two simulation examples. [ABSTRACT FROM AUTHOR]