以可程式邏輯運算晶片發展雷射光學尺訊號解析系統

Development of a Laser Encoder Signal Processing system with Programmable Device

劉奇惠(Chi-Hui Liu)

指導教授 ： 范光照

國立臺灣大學/工學院/機械工程學研究所/碩士(2008年)

https://doi.org/10.6342/NTU.2008.01914

摘要

科技不斷的進步，製造技術不斷推陳出新，所有含高科技領域的機械、電子、材料等工業，都朝著高精密度、高效能的方向邁進。都因創新的技術而達到更高的品質。因此在產品的檢測上，利用可程式的裝置可量測的儀器達到嵌入是系統的目的亦或使系統分工提高系統效能。
本文研究的目的預期可以藉由硬體電路的實現取代電腦平台針對雷射光學尺訊號處理的部份，尤其以多軸運動控制的期望下更能有效達到分工的目的。在利用CPLD作為轉換電路訊號的核心建立獨立的轉換介面，轉換後的數位訊號藉由FPGA可程式邏輯運算晶片寫入解析訊號程式，透過此系統得知實際的位移資訊，達到線性量測的目的，並即時回饋位移資料予控制單元。
在訊號的處理方面，利用FIFO的觀念建立高速計數補償的方法，可以確保訊號因光學尺雜訊過大時仍可正確計數。另一方面建立數位修正訊號中心的方法，可以確保中心飄移時能即時補償。
經SIOSMI5000雷射干涉儀的校驗後，在依密閉槍體內無任何溫度、濕度、震動補償環境下，光學系統在15mm量測範圍內，量測準確性在25nm以下，重複性在20nm以下。

關鍵字

FPGA ； CPLD ； 細分 ； 雷射光學編碼器

並列摘要

Along with constant development in high technology, fields like mechanical engineering, electrical engineering, and material engineering are heading to researches of high precision and high performance. Thus, this research offers the programmable device (embedded device) to improve better performance.

By using Complex Programmable Logic Device (CPLD) to help Analog Digital Converter (ADC) sample the digital signal obtained from Interferometer’s analogical signal, Felid Programmable Gate Array (FPGA), with high speed operation, will process the retained digital data and immediately send the real displacement data back to control unit to further achieve higher performance.

In respect of signal processing, signal correcting is based on first in first out (FIFO) architecture circuit. This method assures correct counting of periodic signal when signal is decaying caused by interferometer. Also, FIFO architecture is used to correct DC draft in real time.
To verify the theoretical predictions and the overall system specifications of the system, the SIOS MI5000 laser interferometer is adopted as the calibration tool. Within the distance of 15mm, the measuring is conducted in a close chamber, a regular laboratory environment, without using conditions of temperature control, humidity control and anti-vibration. The maximum error is 25nm and the repeatability is below 20 nm.

並列關鍵字

FPGA ； CPLD ； Interpolation ； laser encoder

參考文獻

【10】 賴子發 超音波馬達智慧型奈米定位控制系統之研究台灣大學機械所碩士論文，國立台灣大學機械所碩士論文(2006)

【1】 Ju-Yi Lee, “A phase quadrature interferometer for measuring the small optical rotation angle of a chiral medium,” Optics Communications (2007)

【2】 Chyan-ChyiWu, “ Optical heterodyne laser encoder with sub-nanometer resolution,” MEASUREMENT SCIENCE AND TECHNOLOGY(2008)

【3】 Cheng-Chih Hsu , “ Reflection type heterodyne grating interferometry for in-plane displacement measurement,” Optics Communications (2007)

【4】 Ju-Yi Lee, “ Measurement of refractive index change by surface plasmon resonance and phase quadrature interferometry,” Optics Communications