2012年6月19日学术报告信息

SEMINAR NOTICE

Title: Quantification of interactions in multiloop control systems using directed spectral decomposition

Speaker: Dr. Arun Tangirala, IIT-Madras, India

Time: Tuesday, June 19 at 10:00

Place: 407, Central Main Building, Tsinghua University

Abstract:

Interactions among control loops is a critical and challenging issue in the control of multivariable systems. The focus of this work is on analysis and quantification of interactions in multiloop or decentralized control systems. Existing interaction measures suffer from one or more of the following limitations: (i) the lack of a direct connection to a performance metric (ii) assumption of the availability of process models and (iii) the approximate and/or a heuristic nature of the approach to their development, resulting only in approximate indicators of interaction. This work presents an exact quantifier of interaction that arises out of a directional decomposition of the loop variance using methods of causality (directional) analysis in frequency- domain. The main result is that the spectrum of the filtered output can be decomposed into (i) an interaction-and-feedback invariant term and (ii) an interaction-dependent term. The associated filter can be derived from the closed-loop data and is related to the diagonal element of the multiloop sensitivity function. The invariant term is the variance of the output under open-loop conditions and is shown to be as solely dependent on the control pairing. Variance measures corresponding to the invariant and interaction terms are introduced. The utility of the measure is that it can be computed from closed loop data as well as from the process model. Simulation case studies are presented in support of the theoretical results.

Biography:

Arun K. Tangirala received his Bachelors degree in Chemical Engineering from the Indian Institute of Technology Madras, India and his Ph.D degree in Process Control from the University of Alberta, Edmonton, Canada in 2001. After a brief stint as a postdoctoral fellow for eight months at the Department of Chemical \& Materials Engineering, University of Alberta, he worked as a research manager at the same department until December 2004. Subsequently, he joined the Department of Chemical Engineering, IIT Madras where he is an Associate Professor.

He is a recipient for several awards for teaching at the University of Alberta and research presentations at several international conferences. His research interests include closed-loop performance monitoring, causality analysis, multivariate statistical data analysis, fault detection and diagnosis, and modelling and control of fuel cell systems.