Identification of a time-varying mechanical system using the Akaike information criterion

This article deals with the use of Akaike information criterion in the case of an identification problem of a time varying mechanical system. We studied a prismatic beam with a disk excited in torsion to illustrate how the proposed approach can be implemented. The boundary conditions of the beam can change in a controlled way during the experiment. Therefore, our system can be considered as a one d.o.f. system with time-varying parameters. A method based on least-square estimates is used for the identification of the parameters. The use of the Akaike information criterion allows to choose automatically the order of polynomial basis used during the estimation step of the derivatives of the measured angle signal. It is shown through an experimental validation that the AIC criterion is a robust and automatic tool for numerical estimation of signal derivatives.