Lu, Chung-JenChung-JenLuHung, Chia-HsingChia-HsingHung2008-11-042018-06-282008-11-042018-06-28200810489002https://www.scopus.com/inward/record.uri?eid=2-s2.0-54049089301&doi=10.1115%2f1.2948415&partnerID=40&md5=33dab70db3ad84b820ce445758ad8dc3http://ntur.lib.ntu.edu.tw//handle/246246/85790Ball-type automatic balancers can effectively reduce the vibrations of optical disk drives due to the inherent imbalance of the disk. Although the ball-type automatic balancer used in practice consists of several balls moving along a circular orbit, few studies have investigated the dynamic characteristics of ball-type balancers with more than two balls. The aim of this paper is to study the dynamic characteristics of a three-ball automatic balancer. Emphasis is put on the effects of the number of balls on the stability of the perfect balancing positions - the equilibrium positions where the disk is perfectly balanced. A theoretical model of an optical disk drive packed with a three-ball automatic balancer is constructed first. The governing equations of the theoretical model are derived using Lagrange's equations. Closed-form formulas for the equilibrium positions are presented. The stability of the perfect balancing positions is checked with the variations for a pair of design parameters. Stable regions of the perfect balancing positions in the parameter plane of a three-ball balancer are identified and compared with those of a two-ball balancer. Copyright © 2008 by ASME.application/pdf868268 bytesapplication/pdfen-USBalancing; Cable stayed bridges; Data recording; Data storage equipment; Disks (structural components); Drives; Optical data storage; Optical disk storage; Optical recording; Videodisks; Automatic balancers; Ball-type; Circular orbits; Closed-form; Design parameters.; Dynamic characteristics; Equilibrium positions; Governing equations; Lagrange's equations; Optical disk drives; Parameter planes; Stability analyses; Theoretical models; Spheresjournal article10.1115/1.29484152-s2.0-54049089301http://ntur.lib.ntu.edu.tw/bitstream/246246/85790/1/02.pdf