A practical loop pairing criterion for multivariable processes

Utilizing both steady state gain and bandwidth information of the process open loop transfer function elements, this paper presents a new dynamic loop pairing criterion for decentralized control of multivariable processes. Through defining an effective gain matrix, the loop pairing procedures of popular relative gain array method is directly extended to the new method which can reflect dynamic loop interactions under finite bandwidth control. Compared with existing methods, this method is simple, effective, and easy to be understood and applied by control engineers. Several examples, for which the RGA based loop pairing criterion gives an inaccurate interaction assessment, are employed to demonstrate the effectiveness of the proposed method.