應用高斯模型探討硬碟動態特性兼論其抗振之改善

Abstract

本論文以理論分析與實驗量測探討外部衝擊對硬碟造成之擾動，並分別討論在自由、固定與阻尼邊界條件下之硬碟動態特性，其中理論分析部份，應用高斯函數分析時域訊號，探討硬碟受衝擊後之最大接觸力與接觸時間，並與赫茲接觸理論分析結果相互比較；同時也透過傅立葉轉換分析頻域訊號，探討硬碟受衝擊後之擾動幅度。在實驗量測部份，本研究依照四個步驟量測硬碟之動態特性。首先，應用紅外線熱像儀量測硬碟之全場溫度分佈，確認讀寫晶片為硬碟主要發熱源；其次，應用雷射位移計量測硬碟全場輪廓與振動，並搭配紅外線熱像儀之量測結果，規劃量測點與敲擊點；之後，應用衝擊鎚在硬碟表面施予衝擊訊號，透過光纖位移計量測擾動訊號；最後配合理論模型對衝擊訊號與擾動訊號進行時域與頻域分析，探討邊界條件、衝擊訊號、擾動訊號三者間的交互關係。研究結果顯示，硬碟受衝擊後之頻率響應，其共振頻之涵蓋範圍小於2,500 ；制振鋁箔膠帶對外部擾動之抑制能力，經實驗結果發現可降低硬碟主軸馬達之敏感度。

The main contribution of this thesis is to investigate the dynamic characteristics of hard disk drive (HDD) under perturbation, and to suggest suitable boundary conditions for enhancing its stability. Free, fixed and damping conditions are analyzed by using Hertzian contact theory, Gaussian function, and short-time Fourier transform. After the impulse points and measuring points are designed via infrared thermography and laser displacement measurement, impulse and response signals are provided from impact hammer and fiber-optical measurement system. To analyze the physical traits both in time and frequency domain, the analytical methods are applied to the empirical signals, and presented abundant results related to dynamic characteristics. In the analyses of time domain, the main traits of dynamic response are contact time and maximum contact force; in the analyses of frequency domain, the important features are resonant frequency and frequency spectrum. By analyzing the physical traits in different boundaries, damping condition provides prior ability of anti-vibration. Though there are some shortages in different analytical and experimental methods, the thesis still successfully establishes one kind of damping condition, and confirms its ability based on the abundant theoretical and experimental analyses. In the future work of optimization, the finite element method is a practical solution, and indicates suitable locations of damping foil.