H-Infinity State Feedback Control for a Class of Networked Cascade Control Systems With Uncertain Delay

Based on practical industrial process control, a typical configuration for networked cascade control systems (NCCSs) is analyzed. This kind of NCCSs with state feedback controllers, in which the network-induced delay is uncertain and less than a sampling period, is studied. The sufficient condition for the stabilizability of the NCCSs without disturbances is proposed, and the state feedback stabilization control laws are derived via Lyapunov stability theory and linear matrix inequality (LMI) approach. For the NCCSs with disturbances, the criterion of its robust asymptotically stability is derived and the ¿ -suboptimal state feedbackH¿control laws are designed. The ¿-optimal state feedbackH¿control laws are also put forward by optimizing a set of LMIs. A simulation example of a NCCS for the main steam temperature in a power plant is given to demonstrate the effectiveness of the proposed approaches.