Identifying the modes of the scale model corresponding to the Grantecan telescope´s primary mirror

The goal of this paper is to present the method used for the modal identification of the scale model corresponding to the Gran Telescopio Canarias´ (Grantecan´s) primary mirror. This scale model has been designed and built with the purpose of testing the dynamic characteristics of the 10 m diameter primary mirror of the Grantecan telescope. This win be situated on the island of La Palma and its construction will be finished by 2004. Consequently, it is essential that the scale model is available in order to make the trials which are required. Concretely, the design of a controller for noise rejection in the Grantecan´s primary mirror requires some previous tests in the scale model. To be able to use the scale model for checking the controllers designed for the telescope´s primary mirror it is necessary to identify its vibration modes in order to obtain a model which characterizes it. This is what we have done using the results of some open-loop trials made with the scale model