Adaptive output feedback tracking for a class of nonlinear systems with quantized input and output

In this paper, an adaptive output feedback tracking for a class of uncertain nonlinear systems with input and output quantization is investigated. A new controller structure is introduced in which a modified output quantizer is proposed so that its first-order derivative exists, and an observer is designed with quantized input and output as its input signals. Then, with dynamic surface control as a tool, an adaptive recursive design is developed which can avoid higher-order derivatives of the quantized output signal. It is proved that, with the proposed scheme, coarser input and output quantization can be achieved and the tracking error can converge to a small residual set by appropriately choosing some design parameters.