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    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/3190

    Title: 光碟機主軸馬達偏心運轉導致讀取誤差之伺服控制研究
    Authors: 林永泓;Yong-hong Lin
    Contributors: 機械工程研究所
    Keywords: FXLMS;適應性前饋控制;主軸馬達;伺服控制
    Date: 2009-07-15
    Issue Date: 2009-09-21 12:08:30 (UTC+8)
    Publisher: 國立中央大學圖書館
    Abstract: 光碟片儲存密度與光碟機讀取倍速不斷提昇情況下,伺服控制精確度及主軸馬達轉速皆有提高之必要性;承載光碟片之主軸馬達在高倍速轉動容易發出振動,尤其以光碟片質量分佈不均勻、主軸馬達機構有微量偏心之因素,所造成劇烈振動更為明顯。 光碟機本身雖擁有滾珠自動平衡系統、橡膠阻尼及領先落後補償器,可以減少些許受振動影響之聚焦及定軌誤差;當主軸馬達不存在偏心、滾動摩擦阻力之狀態時,才能有消除徑向振動之效果;橡膠阻尼只能消除特定轉速頻率之振動,對於倍頻振動所產生之誤差,則無法有效達到抑制效果;聚焦及定軌伺服為控制音圈馬達移動光學讀取頭,維持在正確資料軌道上讀取資料。而高倍速主軸馬達偏心旋轉之劇烈振動,將導致聚焦及定軌誤差超過容許誤差範圍,則無法將馬達轉速順利提昇至高倍速讀取。 研究中以濾波型最小均方 (FXLMS) 為基礎,並搭配可變收斂因子 (RVSS) 演算法,以無感測器之適應性前饋控制,增加光碟機讀取性能;經由實驗結果顯示,可有效地抑制轉速頻率與倍頻之讀取誤差,進而改善滾珠自動平衡效果、解決橡膠阻尼只能吸收特定頻率振動干擾、增加光碟機伺服控制精確度、完成讀取倍速上升以提高光碟機傳輸速率。 In the trend of increasing data storage density of the optical disc and reading rate of the DVD drives, it’s necessarily to improve accuracy of servo control system and raise rotation speed of spindle motor. The spindle motor which derives disc easily causes strong vibration in high speed for eccentricity of spindle motor and disc. There are automatic ball balancing, rubber damper and lead-lag control in the optical disc devices to reduce focusing and tracking error caused by vibration. The automatic ball balancing is capability to eliminate radial vibrations under the conditions that eccentricity, damping and friction are not present for spindle motor. The damper absorber only suppress vibration at a specific frequency and difficult to overcome the focusing and tracking error for the harmonic vibration. The servo control of the optical disc drives controls a voice coil motor which moves an optical pick up head to accurate data track. The strong vibration causes focusing and tracking error arising over the allowed range and leads spindle motor to decrease rotation speed for pick up data. In the study, the senseless adaptive feedforward control (AFC) which uses RVSS-FXLMS algorithm aids the original servo control system of DVD drives for improving reading performance. The experiment results demonstrate the senseless AFC can successfully eliminate focusing and tracking error arising form the eccentricity of the spindle and overcome the rotation speed is decreased in the strong vibration.
    Appears in Collections:[機械工程研究所] 博碩士論文

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