Packet Management for Optimizing Control Performance in Real-Time Feedback Control Systems

In real-time feedback control systems, control performance, e.g., control cost and tracking error, is significantly affected by information freshness, which in turn relies heavily on the design of the feedback update policy. In this paper, we study the update policy for real-time feedback control systems. We first discuss the relationship between the age of information (AOI) and control performance, where AOI represents the level of "dissatisfaction" for information staleness. We find that minimizing AOI is not always equivalent to optimizing the control performance. Then, a new metric, called the value of information (VOI), is proposed to evaluate the timeliness of system update by linking AOI to the decay rate of the control system. By maximizing VOI, we design a new update policy, called the α - wait, which has superiorities in improving both control performance and communication cost. Finally, simulation results verify our method.