Detection of no-model input/output combinations in MIMO systems subject to noise and unmeasured disturbances

A method is proposed to detect if there is no coupling between an input and an output in open-loop systems. The proposed technique is applicable to MIMO systems, i.e., the intent is to detect models in a transfer matrix. Traditional approaches to input/output (IO) selection are usually performed after the plant model is identified. The proposed approach is applied during the pre-identification stage and it is based on cross correlation and fuzzy logic analysis. A study case involving identification of a 7×6 simulated system is discussed, as well as an analysis of the influence of detecting no-model IO pairs in the identification process.