Controller design for integrating and runaway processes involving time delay

This paper presents an efficient method for the design of controllers for integrating and runaway processes. The method is based on model matching in the frequency domain. The presence of open‐loop instability as well as pure time delay in the process models make the design task challenging for these classes of processes. The goal is to achieve low‐order, easily implementable cascade controllers in a unity‐output‐feedback configuration. It is shown that the central problem is in the selection of appropriate reference models. Several key constraints are developed which relate a given process model to a class of reference models for achieving total stability. Typical design examples are presented to clearly illustrate the various mathematical techniques.