Dynamic Analysis of the Optical Disk Drives Equipped with an Automatic Ball Balancer with Consideration of Torsional Motions

2005 ◽  
Vol 72 (6) ◽  
pp. 826-842 ◽  
Author(s):  
Paul C. P. Chao ◽  
Cheng-Kuo Sung ◽  
Chun-Chieh Wang
Keyword(s):  
Multiple Scales ◽  
Spindle Motor ◽  
Optical Disk ◽  
Torsional Stiffness ◽  
Torsional Motion ◽  
Disk Drives ◽  
Scaled Model ◽  
Supporting Plate ◽  
Steady State Solutions ◽  
Balanced Solution

This study is dedicated to evaluate the performance of an automatic ball-type balancer system (ABS) installed in optical disk drives (ODDs) with consideration of the relative torsional motion between the ODD case and the spindle-disk-ABS-turntable system, noting that the turntable is the supporting plate structure for disk, pickup, and spindle motor inside the ODD. To this end, a complete dynamic model of the ABS considering the torsional motion is established with assuming finite torsional stiffness of the damping washers, which provides suspension of the spindle-disk-ABS-turntable system to the ODD case. Considering the benchmark case of a pair of balancing balls in an ABS, the method of multiple scales is then applied to formulate a scaled model for finding all possible steady-state solutions of ball positions and analyzing corresponding stabilities. The results are used to predict the levels of residual vibration, with which the performance of the ABS can then be reevaluated. Numerical simulations are conducted to verify theoretical results. It is deduced from both analytical and numerical results that the spindle speed of an ODD could be operated above both primary translational and secondary torsional resonances in order to guarantee stabilization of the desired balanced solution for a substantial vibration reduction.

Effects of Rolling Friction of the Balancing Balls on the Automatic Ball Balancer for Optical Disk Drives

2005 ◽  
Vol 127 (4) ◽  
pp. 845-856 ◽  
Author(s):  
Paul C.-P. Chao ◽  
Cheng-Kuo Sung ◽  
Hui-Chung Leu
Keyword(s):  
Steady State ◽  
Multiple Scales ◽  
Rolling Friction ◽  
Friction Model ◽  
Optical Disk ◽  
Contact Dynamics ◽  
Hertzian Contact ◽  
Disk Drives ◽  
Scaled Model ◽  
Stick Slip

This study is devoted to evaluating the performance of an automatic ball-type balance system (ABB) installed in optical disk drives (ODDs) with consideration of the rolling friction between the balancing balls and the ball-containing race of the ABB. Research has been conducted to study the performance of the ABB by investigating the nonlinear dynamics of the system; however, the model adopted to describe the rolling friction between the balancing balls and their race was a simple stick-slip type, which does not reflect the realistic contact dynamics, leading to an inaccuracy in predicting ABB performance. In this study, a complete dynamic model of the ABB including a detailed rolling friction model for the balls based on Hertzian contact mechanics and hysteresis loss is established. The method of multiple scales is then applied to formulate a scaled model to find all possible steady-state ball positions and analyze stabilities. It is found that possible steady-state residing positions of the ball inside the race are multiple and form continuous ranges. Numerical simulations and experiments are conducted to verify the theoretical findings, especially for the rolling friction model. The obtained results are used to predict the level of residual vibration, with which the guidelines on dimension design and material choices of the ABB are distilled to achieve desired performance.

Effects of Rolling Friction of the Balancing Balls on the Automatic Ball Balancer for Optical Disk Drives

2004 ◽  
Author(s):  
Paul C.-P. Chao ◽  
Chi-Wei Chiu ◽  
Cheng-Kuo Sung ◽  
Hui-Chung Leu
Keyword(s):  
Steady State ◽  
Multiple Scales ◽  
Rolling Friction ◽  
Friction Model ◽  
Optical Disk ◽  
Contact Dynamics ◽  
Disk Drives ◽  
Scaled Model ◽  
Stick Slip ◽  
Balance System

This study is devoted to evaluate the performance of an automatic ball-type balance system (ABB) installed in optical disk drives (ODD) with consideration of the rolling friction between the balancing balls and the ball-containing race of the ABB. Researches have been conducted to study the performance of the ABB by investigating the nonlinear dynamics of the system; however, the rolling friction model adopted was a simple stick-slip type, which does not reflect the true contact dynamics between rolling balls and their races, leading to an inaccuracy in predicting ABB performance. In this study, a complete dynamic model of the ABB including a detailed rolling friction model based on contact mechanics is established. The method of multiple scales is then applied to formulate a scaled model to find all possible steady-state ball positions and analyze stabilities. It is found that possible steady-state residing positions of the ball inside the race are multiple and form continuous ranges. Numerical simulations and experiments are conducted to verify the validness of the theoretical findings. The obtained results are used to predict the level of residual vibration, with which the guidelines on dimension design and material choices of the ABB are distilled to achieve desired performance.

Effects of Nonlinear Damping Washers on the Automatic Ball Balancer for Optical Disk Drives

2005 ◽  
Author(s):  
Cheng-Kuo Sung ◽  
Paul C. P. Chao ◽  
Ben-Cheng Yo
Keyword(s):  
Nonlinear Dynamics ◽  
Steady State ◽  
Multiple Scales ◽  
Method Of Multiple Scales ◽  
Dynamic Performance ◽  
Nonlinear Damping ◽  
Disk Drives ◽  
Optical Disc ◽  
Scaled Model ◽  
Jump Phenomena

This study is devoted to explore the effect of nonlinear dynamics of damping washers on the dynamic performance of automatic ball balancer (ABB) system installed in optical disc drives. The ABB is generally used on rotational system to reduce vibration. Researches have been conducted to study the performance of the ABB by investigating the nonlinear dynamics of the system; however, the model adopted often consider the damping washer in a typical ABB suspension system as a linear one, which does not reflect the fact that the practical washers are inevitably exhibit nontrivial nonlinear dynamics at some range of operation, deviating the ABB performance away from the expecteds. In this study, a complete dynamic model of the ABB including a detailed nonlinear model of the damping washers based on experimental data for practical wahers is established. The method of multiple scales is then applied to formulate a scaled model to find all possible steady-state ball positions and analyze stabilities. It is found that with reasonable level of nonlinearity, the balancing balls of the ABB are still reside at the desired positions at steady state, rendering expected vibration reduction; however, jump phenomena also occurs as the spindle operated through natural frequency of the suspension, causing unwanted system vibrations. Numerical simulations and experiments are conducted to verify the theoretical findings. The obtained results are used to predict the level of residual vibration, with which the guidelines on choices of the nonlinear damping washers are distilled to achieve desired performance.

The Dynamics of a Ball-Type Balancer System Equipped with a Pair of Free-Moving Balancing Masses

2001 ◽  
Vol 123 (4) ◽  
pp. 456-465 ◽  
Author(s):  
Jaan-Rong Kang ◽  
Chang-Po Chao ◽  
Chun-Lung Huang ◽  
Cheng-Kuo Sung
Keyword(s):  
High Speed ◽  
Multiple Scales ◽  
Design Guidelines ◽  
Disk Drives ◽  
Rotating System ◽  
Radial Vibrations ◽  
First Order ◽  
System A ◽  
Autonomous Differential Equations ◽  
Steady State Solutions

This study is devoted to evaluate the performance of a ball-type balancer system that is installed in high-speed optical disk drives. The ball-type balancer system, composed of a circular runway and free-moving balls inside, is designed for reducing radial vibrations induced by the inherent unbalance of the rotating system. A balancer system equipped with a pair of balls is considered in this study for its capability to reach possible near-elimination of radial vibrations as opposed to the serious sizing problem of a single balancing-ball system. A mathematical model is first established to describe the dynamics of the balls and rotor system. Utilizing the method of multiple scales and assuming the smallness of radial vibrations, the system dynamics on the slow time scale is represented by eight first-order autonomous differential equations, which accommodate the radial vibratory motions and ball behaviors. The steady-state solutions of these slow equations are then solved and their stability analyzed to predict settling ball positions. The residual vibrations are computed to evaluate the performance of the balancer system and then the design guidelines are distilled for engineers to design the balancer system.

Dynamic Analysis of the Optical Disk Drive System Equipped With an Automatic Ball Balancer With Consideration of Torsional Motion

2003 ◽  
Author(s):  
Chun-Chieh Wang ◽  
Cheng-Kuo Sung ◽  
Paul C. P. Chao
Keyword(s):  
Steady State ◽  
Multiple Scales ◽  
Substantial Reduction ◽  
Disk Drive ◽  
Optical Disk ◽  
Balance System ◽  
Optical Disk Drive ◽  
The Stability ◽  
Steady State Solutions ◽  
Theoretical Results

This study is dedicated to evaluate the stability of an automatic ball-type balance system (ABS) installed in Optical Disk Drives (ODD). There have been researchers devoted to study the performance of ABS by investigating the dynamics of the system, but few consider the motions in torsional direction of ODD foundation. To solve this problem, a mathematical model including the foundation is established. The method of multiple scales is then utilized to find all possible steady-state solutions and perform related stability analysis. The obtained results are used to predict the level of residual vibrations and then the performance of the ABS can be evaluated. Numerical simulations are conducted to verify the theoretical results. It is obtained from both analytical and numerical results that the spindle speed of the motor ought to be operated above primary translational and secondary torsional resonances to stabilize the desired steady-state solutions for a substantial reduction in radial vibration.

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