Process identification, uncertainty characterisation and robustness analysis of a pilot-scale distillation column

In this paper different approaches for developing robust advanced control techniques are investigated. A pilot-scale distillation column connected to an industrial distributed control system (ABB MOD 300) that in turn has been interfaced to a VAX-cluster through an Ethernet Gateway is used as a pseudo-industrial set-up to perform these studies. A novel robust multivariable, low order, high performance, model based controller was designed and implemented as a standard PID block within the distributed control system. To provide a systematic approach for designing such an advanced robust controller, several techniques such as dynamic modelling, system identification, uncertainty identification and characterisation etc., are incorporated. The problem of uncertainty characterisation is fully addressed from both theoretical and practical point of view. Both structured and highly structured uncertainty characterisation approaches are used to investigate the robust stability and performance of the control system. Several practical techniques are proposed for designing a robust model-based controller that are readily applicable in an industrial environment. Thr paper is accompanied by several simulations and also experimental evidences which demonstrate the effectiveness of the proposed approach, (C) 1999 Elsevier Science Ltd. All rights reserved.