使用壓電彎片於近場光碟機的飛行高度控制

Abstract

近場光碟機利用近場光學的技術，使得飛行讀寫頭得以突破繞射極限，增加資料的儲存容量以及密度。然而，讀寫頭的控制效能有待增強。本研究中應用壓電彎片取代在一般讀寫頭上的撓片設計，並執行系統鑑別求得壓電彎片的數學模型。為了即時控制，藉著DSP控制器的高速運算，並以雙光束雷射都卜勒干涉儀作為感測器，使用PID 控制方法達成壓電彎片的飛行運動控制，在近場光碟片以5400rpm轉動時，儘管碟片變形而且飛行讀寫頭振動，都保持著穩定的飛行高度。

Based on near-field optics, a flying pickup head is employed in optical disk drives, so as to increase data storage capacity and density. However, it remains to enhance flying height control performance of the pickup head. This study attaches a piezoelectric bender to the pickup head. System identification is carried out to obtain a transfer function as the plant model. For real-time control, this study uses a DSP motion control card to execute control algorithm and uses a double-beam laser doppler interferometer for sensing head-disk spacing. A PID control method deals with the PZT bender motion to maintain a stable flying height, in spite of optical disk deformation and flying head vibration during near-field disk rotation at 5400rpm.