Comparison of experimental modal analysis with operational modal analysis for assessment of the dynamic behaviour of a machine tool component

Operational modal analysis (OMA) makes possible a characterisation of the dynamic behaviour during operation unlike the experimental modal analysis (EMA), known as standard, which can only be employed in standstill and thus neglects effects occurring during operation. Nevertheless, OMA requires excitation that has features of a white noise signal, which is difficult to fulfil in the case of machine tools. In this paper, effects of various excitation signals on the results evaluated with various methods of OMA are investigated on a joint of a parallel kinematic machine tool and compared with EMA.