車用的光碟機容易受到外界振動的干擾進而導致光碟片無法順利讀取，因此我們實驗室利用修正型適應性複合伺服控制器(MAHC)並結合RVSS-FXLMS來消除尋軌及聚焦的誤差，此方法在100 Hz以內的誤差有很好的消除效果，但依然不能使光碟機從不能讀取變成可以讀取，因此加上了被動式的吸震海綿之後，方可消除100 Hz以上的誤差，並且能使光碟機從不能讀取變成可以讀取，因此為了探討是什麼原因造成高頻的尋軌誤差，此研究利用實驗設計的方式探討真正的原因，並利用數值模擬來探討滾珠對於平衡主軸的有效範圍。

In a vehicular environment, the DVD drives are apt to be influenced by severe external vibration. Therefore, At our laboratory a modified adaptive hybrid servo controller (MAHC) associated with the robust variable step-size filter-x-least-mean-square (RVSS-FXLMS) was applied to eliminate the focusing and tracking errors at low frequencies from 0 Hz to 100 Hz. However, no matter how the tracking errors under 100 Hz frequency was suppressed, the DVD data-reading still failed since there existed errors at high frequencies. Hence, the sponge was added on the DVD drive to aid MAHC associated with RVSS-FXLMS to eliminate the tracking errors at higher frequencies from 100 Hz to 500 Hz, and then the DVD drive was able to read data well. At the beginning, to explore the causes to make tracking errors large at high frequencies, the balancing balls were suspected. However, this study used a series of experiments to explore exact reasons of the tracking errors at high frequencies. It is found that these errors are generated by structural resonance but not balancing balls on the DVD drive. On the contrary, the balancing balls play an effective role to resolve the unbalanced disk and spindle. In this study, the automatic ball balancer (ABB) dynamic motion equations are derived, and direct computer simulations are carried out. The simulated results confirm that the balancing balls are effective when the unbalanced disk or spindle is operated above the critical speed (ω/ωn=1). Therefore, if the spindle speed of the DVD drives is higher than the structural resonance frequency, the balancing balls will eliminate the tracking errors.

[1]　Blu-ray Disk Association, 2008, “What is Blu-ray Disk,” http://www.blu-raydisc.com/en/nlmp/Blu-rayGlobal.html (2008).
[2]　Tsai, Y.L., “Effective suppression of Focusing and Tracking Errors for DVD drives in Severe Vibratory Environment,” Master thesis in Chinese, National Central University, (2009).
[3]　Heo, J. W., Chung, J. and Park, J.M., “Vibration and Noise Reduction of an Optical Disk by Using a Vibration Absorber,” IEEE Transactions on Consumer Electronics, Vol. 48, No. 4, pp. 874-878 (2002).
[4]　Lim, S., Kim, K., Cho, U., Park, N. C., Park, Y. P., Park, K. S. and Soh, W. Y., “Cantilever Dynamic Vibration Absorber for Reducing Optical Disk Drive Vibration,” IEEE Transactions on Magnetics, Vol. 45, No. 5, pp. 2198-2201 (2009)
[5]　Lee, J. and Van Moorhem, W. K., “Analytical and Experimental Analysis of a Self-Compensating Dynamic Balancer in a Rotating Mechanism,” Journal of Dynamic Systems, Measurement and Control, Vol. 118, No. 3, pp. 468-475 (1996).
[6]　Chung, J. and Ro, D.S., “Dynamic Analysis of an Automatic Dynamic Balancer for Rotating Mechanisms,” Journal of Sound and Vibration, Vol. 228, pp. 1035-1056 (1999).
[7]　Chen, Y. D., Fuh, C. C. and Tung, P. C., “Application of Coil Motors in Active Dynamic Vibration Absorbers,” IEEE Transactions on Magnetics, Vol. 41, No. 3, pp. 1149-1154 (2005)
[8]　Chang, K., Shim, I. and Park, G., “Adaptive Repetitive Control for an Eccentricity Compensation of Optical Disk Drivers,” IEEE Transaction on Consumer Electronics, Vol. 52, No. 2, pp. 445-450 (2006).
[9]　Lee, M. N. and Jin, K. B., “An Optimal Tracking Controller Design Based on the Estimation of Tracking Vibration Quantity,” IEEE Transaction on Consumer Electronics, Vol. 51, No. 2, pp. 478-483 (2005).
[10]　Kim, J., Lim, K. S. and Kim, S., “Dynamic Eccentric Error Compensation for Track following Control of Optical Disk Driver,” IEEE International Symposium on Circuits and Systems, pp. 3808-3811 (2007).
[11]　Chang, C. H. and Liu, T. S., “LQG Controller for Active Vibration Absorber in Optical Disk Drive,” IEEE Transactions on Magnetics, Vol. 43, No. 2, pp. 799-801 (2007).
[12]　Widrow, B., Glover, J. R., Mccool, J. M., Kaunitz, J., Williams, C. S., Hern, R. H., Zeidler, J. R., Dong, E. and Goodlin, R. C., “Adaptive Noise Canceling: Principles and Applications,” Proceedings of the IEEE, Vol. 63, No. 12, pp. 1692-1716 (1975).
[13]　Morgan, D. R., “An Analysis of Multiple Correlation Cancellation Loops with a Filter in the Auxiliary Path,” IEEE Transactions on Acoustics, Speech and Signal Processing, ASSP-28, pp. 454-467 (1980).
[14]　Kwong, R. H. and Johnston, E. W., “A Variable Step Size LMS Algorithm,” IEEE Transaction on Signal Processing, Vol. 40, No. 7, pp. 1633-1642 (1992).
[15]　Aboulnasr, T. and Mayyas, K., “A Robust Variable Step-Size LMS-type Algorithm: Analysis and Simulation,” IEEE Transactions on Signal Processing, Vol. 45, No. 3, pp. 631-639 (1997).
[16]　Chen, C. M., “Adaptive Focusing Control of DVD Driver System,” Master thesis in Chinese, National Tsing Hua University, (2002).
[17]　Wu, M. D., “Dynamic Investigation and Adaptive Tracking Error Improvement of an Optical Disc Drive,” Master thesis in Chinese, National Central University, (2004).
[18]　Wei, W. T. “Implementation and Application of Adaptive Focusing Control for DVD Drives in Vehicle Systems,” Master thesis in Chinese, National Central University, (2005).
[19]　Chien, C., “Adaptive Hybrid Control for DVD Drivers in Vehicle System,” Master thesis in Chinese, National Central University, (2007).
[20]　Lin, Y. H., “Servo-error Control to Compensate the Eccentricity of Spindle and Disk” Master thesis in Chinese, National Central University, (2009).
[21]　Young, Y. L., “The Analysis of Focusing and Tracking error signal for DVD drivers,” Master thesis in Chinese, National Tsing Hua University, (2000).
[22]　Campos, J., Crawford, M. and Longoria, R., “Rotordynamic Modeling Using Bond Graphs: Modeling the Jeffcott Rotor,” IEEE Transactions on Magnetics, Vol. 41, No. 1, pp. 274-280 (2005)
[23]　Chen, J. S., Yao, L. C., Ho, J. H., Chen, C. Y., Liu, Y. P. and Chang, S. H., “Toward the Application of A Mode-Switching Control Law on the Focus and Tracking Control of An Optical Disk Drive,” National Science Council (NSC94-2213-E007-079), (2006).