Robust parameter design with feedback control

Two commonly used methodologies for mitigating the effect of noise on process output are robust parameter design and on-line control. In many processes, the optimal control law depends on the parameter design solution and vice versa. The need for an integrated approach that combines the two methods is therefore evident. This article develops a parameter design methodology in the presence of feedback control for processes of long duration. Systems that follow a pure-gain dynamic model are considered and the best proportional-integral and minimum mean squared error control strategies are developed using robust parameter design. The proposed method is illustrated using a simulated example and a case study in a urea packing plant.