Adaptive fuzzy quantized control of time-delayed nonlinear systems with communication constraint

This paper explores the problem of quantized fuzzy adaptive tracking control for a class of time-delayed uncertain nonlinear systems with communication constraint. The control signal is first quantized in a newly proposed asymmetric hysteresis-type quantizer before it is transmitted over the networks with limited bandwidth. Then one of major difficulties that block the controller design is that the real control signal is hidden in the coupling dynamics between nonaffine system nonlinearity and rate-dependent hysteretic quantizer. To remove this obstacle, a control separation method established mainly on a new nonlinear decomposition of quantizer is proposed. Unlike previous linear decomposition of quantizer, the nonlinear one does not recourse to some conservative assumptions either on control input or system nonlinearities. In combination with fuzzy backstepping technique and Lyapunov-Krasovskii functional, an adaptive fuzzy controller is developed to guarantee the boundedness of all closed-loop signals, and the asymptotic convergence of tracking error to an adjustable region of zero. Finally, two simulations associated with practical control systems are conducted to verify the effectiveness and applicability of the proposed control protocol.