HIGHLY STRUCTURED STABILITY MARGINS FOR PROCESS-CONTROL SYSTEMS - A CASE-STUDY OF DECOUPLING CONTROL IN DISTILLATION

A robust control problem for chemical processes is addressed using the concept of highly structured stability margins (HSSM). This is based on an improved representation of the uncertainty region that leads to less conservative results than the existing methodologies. HSSM provides a better assessment of low-frequency uncertainty due to strong phase dependence and accomodates arbitrary shapes of the uncertainty region. The HSSM concept is demonstrated by a case study of decoupling control in distillation which has provided an excellent environment in the past to showcase the effectiveness and the utility of various robustness analysis methodologies.