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

• Main Authors: Li-An Weng, 翁瑮安
• Other Authors: Kuang-Yuh Huang
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/b99xa6

碩士 === 國立臺灣大學 === 機械工程學研究所 === 107 === 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.