Continuous-time identification in a space frame
Abstract
The purpose of this study is to show that it is possible to use continuous time identification method with a signal discretized either in space or in time domains. The partial differential equations, and particularly those governing continuous mechanical system behaviour, can be transformed into algebraic equations by using the well known properties of orthogonal functions. Before any identification, it is crucial to perform a good expansion of the signals onto an orthogonal basis. A criterion will be studied to minimize the difference between the projected and the recorded signals. After this expansion step, the identification is performed through a very classical Least Square process. To validate the formalism, two different tests will be carried out: one for a bar in longitudinal motion and a second one with a bending beam. This study shows that it is possible to calculate immeasurable quantities and that this identification is robust to noise. The proposed methodologies and formulations can be easily extended to other orthogonal functions in association with partial differential transformations