Control structure analysis by partial relative gains

A new procedure for analysis and selection of decentralized control structures is presented. In addition to the relative gain array (RGA) for the entire open-loop system, the RGA for the system under partial control is considered. This partial relative gain (PRG) provides necessary conditions for integral controllability and integrity. The PRG also solves the variable pairing problem more reliably than the conventional RGA, which may fail for systems larger than 2/spl times/2.