A ν − gap Factsheet – with Applications to Model Validation

Typical measures for closed loop systems are so-called gaps between two systems, classically either L2 or H2 gap. Here, the distance between to candidate models for a plant can be measured taking all possible combinations of bounded input and output signals into account. Rather recently, a variant of theses gaps, the ν − gap, gained interest in the “identification for control” community. This report states the basic technicalities of this framework along with a motivation, why a new gap is useful. Moreover, the possibilities of examining models set, arising from an identification experiment, in terms of this metric are discussed. Some simple examples are given to illustrate the framework.