壓電蜂鳴致動搭配電容式位移感測之單軸定位系統模組設計開發與探討

Design and Development of a Positioning System Using Piezo-Buzzer Actuator and Capacitive Sensor

翁瑮安(Li-An Weng)

指導教授 ： 黃光裕

國立臺灣大學/工學院/機械工程學研究所/碩士(2019年)

https://doi.org/10.6342/NTU201901520

摘要

本論文旨在設計開發可用於多軸並聯平台之單軸定位系統模組，並以毫米級長行程為目標，進行奈米級精密定位。壓電元件因其解析度高、響應速度快的特性而廣泛地被使用在致動器，本研究考量經濟因素，以取得性高且成本低的壓電蜂鳴片為致動源，並使用超彈性線材搭配調節機構以達到穩定調節徑向預壓力的作用，使其能依慣性滯滑原理產生長行程之精密致動位移。
位移量測選擇使用非接觸感測中結構簡單、靈敏度高、穩定性佳的電容器作提供位置訊息，為避免負載效應，更將其與致動器整合以達到體積緊緻的目的。利用差動式設計擴大量測之線性範圍，配合處理電路將訊號回傳至使用LabVIEW撰寫之定位控制程式形成閉迴路回饋控制。
單軸定位平台整體體積為長95 mm、寬38 mm、高38 mm，致動總行程為10 mm，最小的平均步進量為123 nm，在負載測試實驗中最大軸向負載為16 g。電容感測器在量測總行程為10 mm時，與市售雷射位移計做實驗比對測試，在量測9.3 mm內可以進行有效量測，在量測行程6 mm內線性度為0.36%，並且具動態量測及重複性高的特性。利用閉迴路回饋控制系統以快速步進致動至誤差低於20 um，再進行無段式連續精密定位，最終依據感測器的量測精度，可達nm定位精度。

關鍵字

壓電致動器 ； 電容感測器 ； 超彈性材料 ； 壓電蜂鳴片

並列摘要

In this thesis, design and develop a single axis positioning system module that can be used to multi-axis stages, and reach to millimeter scale long-range positioning with nanometer resolution. Because of its high resolution and speed, piezoelectric elements have been widely used for actuator. For cost reason, the actuator is driven by handy and low-cost piezo buzzer. To keep stable radial pre-load, the superelastic wire is applied to the pre-load mechanism. The application enable the mechanism to produce long-stroke and precision displacement through the intertial stick-slip driving principle.
With the advantage of simple structure, high sensitivity, and great stability, capacitive sensor is used to develop noncontact displacement measurement for the purpose of avoiding loading effect and compacting the size. Using the differential structure and circuit to expand linear measuring range, and return signal to the positioning control algorithm programmed on LabVIEW software to complete the closed-loop control.
The dimensions of the positioning system module are 95 mm in length, 38 mm in wide, 38 mm in height. It can reach to stroke of 10 mm, and the minimum average stepping resolution was 123 nm.While in the bearing test, it can bear the maximum axial load of 16 g. In comparison with the laser displacement sensor in the market, the capacitive sensor can make effective measurement in the range of 9.3 mm within the stroke of 10 mm. Capacitive sensor has linearity of 0.36% in the measurement range of 6 mm and with quick response and high repeatability. Closed-loop control system can auto-position with the positioning error smaller than 20 um, and then use precision adjustment to reach the final target.

並列關鍵字

Piezo actuator ； Capacitive sensor ； Superelastic material ； Piezo buzzer

參考文獻

[1]劉信廷，“三軸閉迴路奈米定位致動系統之設計開發與特性研究”，國立臺灣大學工學院機械工程學系碩士論文，2008。

[2]丁仁峰，“壓電蜂鳴片致動器與環形磁陣列霍爾感測器於三軸定位系統之開發探討”，國立臺灣大學工學院機械工程學系碩士論文，2011。

[3]Tenzer, P.E. and Mrad, R.B., “A Systematic Procedure for the Design of Piezoelectric Inchworm Precision Positioners”, IEEE/ASME Transactions On Mechatronics, Vol. 9, NO. 2, June 2004, pp.427-435.

[4]Pan, P., Yang, F., Wang, Z., and Zhong, B., Nanopositioning Technologies, 2016.

[5]Mazeika, D. and Vasiljev, P., “Linear inertial piezoelectric motor with bimorph disc”, Elsevier Mechanical Systems and Signal Processing, Volume 36, Issue 1, March 2013, pp.110-117.