Time delay produces detrimental effects on the stability and performance of control systems, and the control is generally more difficult unless the delay is compensated.
IMC has a remarkable effect on improving the control performance of systems with large time delays.
Hong Kwang Hyok, a researcher at the Faculty of Automatics, has proposed a modified internal model control based PID (IMC-PID) control strategy by incorporating the structure of predictive functional control (PFC) together with DOB.
First, he used particle swarm optimization (PSO) for the optimal calculation of the IMC filter time constant. Then, he combined PFC and DOB with IMC-PID controller to compensate for the effect of time delay and disturbance. Thus, he could not only enhance disturbance rejection ability but also ensure predictive control.
He applied the proposed method to a first order plus dead time (FOPDT) process to analyze the effectiveness. The simulation results showed that the proposed controller can effectively compensate for the effects of time delay and disturbance.
You can find the details in his paper “Improved IMC-PID Controller Combining Predictive Functional Control Structure and Disturbance Observer” in “Proceedings of KUTIC-2025”.