A Survey of Recent Breakthroughs in Networked Cascade Control Systems

ABSTRACT Cascade control systems (CCSs) consist of at least two nested control loops. This type of control system is widely used in industrial processes, power plants, and chemical processes. A CCS in which the control loops are closed through a real‐time communication network is called a networked cascade control system (NCCS). To reduce the load on communication channels in NCCSs, an event‐triggered scheme (ETS) is proposed. In event‐triggered control, control tasks are executed upon the occurrence of an event. Instead of executing control tasks after a specific time period, they are triggered by events. Certain environmental factors, including stochastic or deterministic cyber‐attacks, cause changes in the dynamics of the closed‐loop system. To model stochastic cyber‐attacks, Bernoulli or Markov distributions are typically used. Moreover, deterministic cyber‐attacks are described by periodic or aperiodic signals. Due to the presence of communication networks in both the inner and outer loops, time delays are inevitable. These delays, as well as packet loss, can lead to reduced system performance or even instability. The goal of this paper is to explore the latest challenges related to NCCSs to familiarize graduate students and researchers in the field of control engineering.