Non-planar dynamic modeling for the optical disk drive spindles equipped with an automatic balancer

This study presents non-planar dynamic modeling and analysis of the spindle–disk system equipped with an Automatic Ball-type Balancer (ABB) system for optical disk drives. Recent studies have shown that the ABB system owns the capability for reducing radial vibrations of the rotating spindle–disk assembly by counter-acting the inherent imbalance. To extend the analysis to be practical, non-planar dynamic modeling and analysis are conducted in this study to re-affirm the pre-claimed capability of the ABB system. Euler angles are first utilized to formulate potential and kinetic energies. Lagrange’s equations are next applied to derive governing equations of motion. Numerical simulations of non-planar motions are finally carried out to calculate two performance indices, the level of residual radial vibration and the tilting angle of the rotating assembly. It is obtained that the levels of residual vibration as compared to those without the ABB, are significantly reduced. On the other hand, the tilting angle of the rotating assembly can be kept small if the ABB is installed below the inherent imbalance of the spindle–disk system.