Stabilization of Networked Control Systems With Time Delays: An Observer-Based Dynamic Quantized Control Approach

In this article, we propose an observer-based dynamic quantized control approach to stabilize networked control systems plagued by time delays. Our first step involves designing an observer-based dynamic quantizer that effectively circumvents saturation, even in the presence of time delays. Notably, the zoom variable of this quantizer can be discretely adjusted. Specifically, the interval between two consecutive adjustments of the zoom variable has a positive lower bound, which contributes to reduced energy consumption. Next, we consider unbounded time delays that may lead to packet loss in networked control systems with limited bit rate. We prove that the system stabilization relies on a mild assumption on packet loss frequency. We then design a controller based on the quantized state of the observer to counteract time delays and maintain system performance. Finally, we provide three numerical examples to validate our theoretical results.