Optimal IMC-PID Controller Incorporating Predictive Functional Control Structure and Disturbance Observer

Abstract

In this paper, a modified internal model control based PID (IMC-PID) control strategy incorporating the structure of predictive functional control (PFC) together with disturbance observer (DOB) is suggested. First, the optimal IMC-PID controller is calculated using particle swarm optimization (PSO) algorithm. Furthermore, combination of PFC and DOB with IMC-PID controller to compensate for the affections of time delay and disturbance not only enhances disturbance rejection ability but also enables the role of predictive control. At that time, the filter time constant of DOB is also determined by PSO algorithm. The predictive output is generated from the structure of PFC and the disturbance estimation is compensated by DOB to the manipulated variable calculated from IMC-PID control. Simulation results on the first order plus dead time (FOPDT) process illustrate the advantages of the proposed control system.