Identification of support stiffness and damping parameters for electromagnetic support system

Electromagnetic support has many advantages, such as: no mechanical friction, without lubrication, long using life, controllable and adjustable support parameters, etc. Its support stiffness and damping parameters are important factors which affect the structure dynamic performance. In this paper, the cantilever beam with an electromagnetic support at end was taken as a research object. The first order natural frequency and logarithmic damping coefficients of this structural system with different excitation current were calculated and tested. Based on the first order natural frequency and logarithmic damping coefficients of the support system which were measured in the experiment, a new method was proposed to identify the support stiffness and damping parameters. The support stiffness and damping parameters of the electromagnetic support with different excitation current were identified according to this method. The identification results showed that there were big deviations between theoretical values and experimental values of electromagnetic support stiffness parameter in most cases, while the experimental values of electromagnetic support damping parameter were always far smaller than the theoretical values.