“Variable selection for decentralized control”

Authors: Sigurd Skogestad and Manfred Morari,
Affiliation: NTNU, Department of Chemical Engineering and California Institute of Technology
Reference: 1992, Vol 13, No 2, pp. 113-125.

Keywords: DIC, relative gain array (RGA), steady-state, integral control, interactions

Abstract: Decentralized controllers (single-loop controllers applied to multivariable plants) are often preferred in practice because they are robust and relatively simple to understand and to change. The design of such a control system starts with pairing inputs (manipulated variables) and outputs (controlled variables). For a nxn plant there are n! possible pairings, and there is a great need for screening techniques to quickly eliminate undesirable pairings. In this paper we present several tests for eliminating pairings which are not decentralized integral controllable (DIC). A system is DIC if there exists a stabilizing decentralized controller with integral action such that the gains of the individual loops may be reduced independently without introducing instability. Note that the DIC is a property of the plant and the chosen pairings. The tests presented are in terms of different measures of the sign of the steady state gain matrix; including the RGA, the determinant and eigenvalues. The relationship to previously presented results is discussed in detail.

PDF PDF (1039 Kb)        DOI: 10.4173/mic.1992.2.3

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  title={{Variable selection for decentralized control}},
  author={Skogestad, Sigurd and Morari, Manfred},
  journal={Modeling, Identification and Control},
  publisher={Norwegian Society of Automatic Control}