Short-Cut Operability Analysis. Part III - Short-Cut Methodology for the Assessment of Process Control Designs.

Abstract

In this paper a methodology for the evaluation and comparison of several control strategies at different stages of the design is developed. The two parts of this methodology extend the previously developed short-cut operability analysis. The first part of the methodology is based on steady state information. It uses the Relative Disturbance Gain (RDG) in conjunction with the Relative Gain Array (RGA) to distinguish between clearly unfavorable control schemes and those which might result in acceptable transient performance. Also, it uses a steady state approach to decide whether a decoupling controller is beneficial and what its structure should be. The second part of the methodology makes use of approximate dynamic information to evaluate which control structures meet the process specifications. Internal Model Control (IMC) with the assumption of a perfect process model is used as an upper bound for the performance obtainable with advanced control.