乾黏附式扁圓形彈簧導引壓電致動器之設計開發

Abstract

本論文提出一種可長行程致動的線性致動器，採用具有高動態、體積小、高出力及微小致動等特性的壓電元件作為致動來源，其被廣泛應用於高精度的致動器中。致動器結合乾黏附式扁圓形彈簧導引裝置，透過慣性滯滑致動原理，以達到長行程且高解析度的致動。乾黏附式扁圓形彈簧導引裝置透過撓性墊片之彈性變形與回復，達成線性導引，且由於彈簧的軸向剛性變化使得導引過程具有低阻力的特性。乾黏附黏膠貼附於扁圓形彈簧上，可提高承載力與致動力，且其本身的黏彈性亦可以達到減振效果，使致動更穩定。利用理論計算與實驗測試，探討扁圓形彈簧的構型及設計參數對導引性能的影響。對慣性滯滑原理進行推導，並分析影響參數與致動性能的關係。影響致動性能的因素包含鋸齒波訊號的驅動電壓及頻率、扁圓形彈簧導引裝置提供的摩擦預力、壓電軸向預力以及負載質量等，皆透過實驗進行致動性能測試與驗證。壓電致動器的尺寸為48 mm x 40 mm x 23 mm，依據測試結果，壓電致動器位移總行程大於5 mm。在摩擦預力4.21 N、驅動電壓60 V及驅動頻率100 Hz的情況下可達到最大致動速度114.12 μm/s；在摩擦預力4.85 N、驅動電壓60 V及驅動頻率400 Hz時，具有最小致動解析度24 nm。

In this thesis, one kind of linear actuator is developed, which is able to achieve long-stroke movements. A Piezo Element is used as the source of power in this actuator, featuring high response speed, high output force and tiny stroke, and it is widely applied in high-precision actuators. Actuator guided by dry adhesive elliptical-shaped spring is able to travel in long distance with high resolution through the inertial stick-slip driving principle. Through the elastic deformation and recovery force of flexible structure and the decrease in axial stiffness of spring, dry adhesive elliptical-shaped spring device can easily achieve linear guiding with a lower resistance force. With dry adhesive sticking on elliptical-shaped spring, both the bearing capacity and driving force of the actuator can be increased; in addition, the viscoelasticity property of dry adhesive makes the movement more stable by decreasing vibration. With theoretical computation and experiment, the influences of the construction and design parameters of elliptical-shaped spring are analyzed. The inertial stick-slip driving principle is study to analyze the relationship between the influential parameters and the actuator’s positioning performance. The influential factors include driving force, driving frequency, frictional preload, axial preload of the Piezo Element and bearing load, and they are all experimentally tested and verified. The dimension of the actuator is 48 mm in length, 40 mm in width and 23 mm in height. According to the testing results, the actuator can travel more than 5 mm. The maximum speed is 114.12 μm/s when the driving voltage is 60 V, driving frequency is 100 Hz, and frictional preload is 4.21 N. While the driving voltage is 60 V, driving frequency is 400 Hz, and frictional preload is 4.85 N, the minimum resolution of the actuator is 24 nm.