A Novel TDF Control Scheme for Integrating and Double Integrating Processes with Time Delay Based on Modified IMC Structure

Abstract

In view of the deficiencies in recent internal model control (IMC)-based scheme for set-point tracking and the load disturbance rejection for integrating and double integrating processes with time delay, a novel scheme based on IMC structure is proposed to deal with the step load disturbance for integrating and double integrating time-delay processes control. A two-degree-of-freedom (TDF) control scheme is introduced to separate the optimization of the load disturbance rejection from set-point tracking. The set-point tracking controller and load disturbance rejection controller are designed based on the process model without time delay. There is only a single adjustable parameter in each of the proposed controllers to make a satisfied trade-off between system response performance and closed loop system robust stability in essence. Straightforward parameter tuning guidelines are provided for the control performance. At the same time, the robust tuning constraints are provided to accommodate process uncertainties in practice. In the end, illustrative examples from the recent literatures are considered to show the effectiveness and flexibility of the proposed method for different types of integrating process control.