The advanced RGA based techniques introduced in chapter 3 provide powerful extensions to the well established RGA methodologies. Each of the proposed RGA extensions solves a problem not considered by the static classical RGA. This chapter considers two advanced approaches for control configuration selection that are not RGA based. These techniques are:
SSV Approach to Input-Output Pairing. In this approach, Structured Singular Values (SSV) is employed to quantify the interaction in linear multivariable plants with diagonal or block diagonal controllers. Closed loop stability and performance under decentralized control corresponding to a selected control structure is also considered. The main ideas are given in section 4.2.
Passivity based Approach to Control Configuration Selection. This recently developed approach is presented in section 4.3. This strategy employs the passivity concept. Although the properties and applications of passivity theory are well known in stability analysis and control systems design, it has been newly introduced in interaction analysis and it uses the so-called degree of passivity.