An approach for nonlinear damping characterization for linear optical scanner

Vibratory systems that are used in linear optical scanners are significantly influenced by the properties of the surrounding fluid. Although, the dominant energy loss in scanner vibrations is caused by viscous effects, especially in non-microelectromechanical system (MEMS) scanners, the relative importance of viscous damping model is not well studied. In this study, a piece-wise method for calculating the damping ratio with logarithmic decrement to produce a numerical model which is able to predict the free response of a linear optical scanner is developed. The damping ratio function used in the model was derived by comparing and minimizing the deviation between the amplitude predicted by numerical model and the experimental data. The efficiency of this approach was tested on the basis of a torsional spring scanner. The results show significant improvement whereby the proposed model predicted the free response with a deviation of only 8% while the general exponential damping model produced a deviation of 20%.