Automatic pairing of MIMO plants using normalized RGA

Input/output pairing is an important task in control of a MIMO process by some SISO controllers. Relative gain array (RGA) is the most important method to find the best pairing. But selection of pairs based on RGA is an offline algorithm which needs some human decision. In this article, Normalized RGA (NRGA) matrix is introduced through the combination of the RGA matrix and its selection rules. Using NRGA, pairing problem can be interpreted as an assignment problem. The well known Hungarian algorithm is applied to the above problem to obtain the optimal pairing.