前饋式零相位誤差強健控制器應用於微型化藍光讀寫頭兩段式致動器設計

Abstract

摘要 有PZT的雙軸控制致動器設計用來提供高速尋軌與聚焦的讀取動作,解決以往微型化讀寫頭(mini-ODD)容易受外在干擾影響而不易快速讀取資料情況,新式的蹺板式雙軸致動器機械上有點對於聚焦能提供更迅速更精確的讀取.主致動器VCM做大範圍的低頻調整移動聚焦尋軌,同時配合PZT精密小範圍高頻的精密調整.遠比傳統單軸VCM來的迅速.在機構的伺服控制方面,期望微型化藍光光學讀寫頭在10800rpm高速運轉下,控制系統一方面能達到高速響應,另一方面對於低頻與高頻的干擾能有效排除,現今雙軸伺服控制設計更比起傳統單軸致動器控制器的設計更顯得困難與複雜,再建模基礎下,建立一個有效的強健干擾觀察迴路對致動器做控制,一方面強健傳統PID控制器對於干擾影響的不穩定性,一方面抑制建模過程中系統不確定因素所帶來的影響.對於突發干擾能做有效抑制.解決微型讀寫頭受外在衝擊時對系統讀取碟片所帶來的影響.另外對於PZT壓電效應與碟盤偏心不平整所產生的週期性干擾,以快速零相位誤差控制迴路(ZPET-FF)控制迴路對其做修正,以強健觀察迴路系統抑制突發干擾,以快速零相位誤差控制迴路抑制週期性干擾,在兩者搭配下期望能更快速的達到系統的預估的頻率響應值是本論文的目的

Abstract A swing-arm/PZT dual-stage actuator is designed to provide high performance solution to realize precise tracking and focusing operation of miniaturized optical disc drive (mini-ODD). Because of its dual-stage mechanical characteristics can perform the focusing action smoother and more precise; the servo system to control such a dual-stage system tends to be more complex than a conventional single-stage ODD system. Based on the modeling results, a robust tracking observer control system with both two degree of freedom control system is proposed. In order to suppress the disturbance quickly, this paper designs the zero phase error tracking controller (ZPETC) plus feed-forward servo loop with the memory of tracking error to satisfy tracking error transient response and improve the sensitive focusing performance of dual-stage miniaturized actuator. The conclusion points out that the proposed robust ZPETC servo system has a precise tracking response and rejects both periodic disturbance and sudden disturbance.