PID Controller Design for a Class of Networked Cascade Control Systems

The issue of PID controllers designing for a typical class of networked cascade control systems with constant network-induced delays is addressed. Cascade control system, wherein the control loops are closed via a real-time network, is called a networked cascade control system(NCCS for short). The system configuration for a typical class of NCCSs is analyzed, and the locations of the network-induced delays are pointed out. With the primary and secondary processes given as first order plus time delay (FOPTD), as well as the desired closed-loop responses, the PID tuning parameters of the primary and secondary controllers are proposed in form of expressions by approximating pure delays with first order Pade expression. Based on MATLAB/Simulink and TrueTime toolbox, both of simulation results and computational results of control performance indices for the NCCS explicitly indicate the superiority of the proposed approach to improve the system performance.