@TechReport{ it:2011-032,
author = {Bj{\"o}rn Halvarsson and Torsten Wik and Bengt Carlsson},
title = {New Input-Output Pairing Strategies Based on Linear
Quadratic {G}aussian Control},
institution = {Department of Information Technology, Uppsala University},
department = {Division of Systems and Control},
year = {2011},
number = {2011-032},
month = dec,
abstract = {Two input-output pairing strategies based on linear
quadratic Gaussian (LQG) control are suggested. In the
first strategy, denoted linear quadratic interaction index
(LQII), input-output pairing suggestions are found from a
minimization of the output signal variance. This index not
only guides to what pairing should be tried, it also gives
a direct measure of how much better a full MIMO controller
can perform. The second proposed interaction measure,
denoted integrating linear quadratic index array (ILQIA),
focuses more on the low frequency behaviour of the
considered plant, such as load disturbances. The strategies
are used to compare the expected performance of
decentralized control structures in some illustrative
examples. The pairing suggestions are compared with the
recommendations previously obtained using other interaction
measures such as the relative gain array (RGA), the Hankel
interaction index array (HIIA) and the participation matrix
(PM). The new strategies are easy to interpret and give
suitable pairing recommendations where other methods may
fail.}
}