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標題: | 雙頻雙模態壓電馬達之最佳化設計 Optimization of a two-frequency-two-mode piezoelectric linear motor |
作者: | Tsung-Yu Chu 朱宗祐 |
指導教授: | 李世光(Chih-Kung Lee) |
關鍵字: | 壓電材料,超音波馬達,行進波,雙模態激發, Piezoelectric material,linear ultrasonic motor,two mode excitation,traveling wave, |
出版年 : | 2018 |
學位: | 碩士 |
摘要: | 本研究主體乃是有限長度的線性超音波馬達,整體目標乃是利用簡單的結構設計,搭配理論分析、數值模擬、與實驗驗證,應用有限結構在共振時之波傳疊加性質來驅動直線型位移平台,研究目標包含研發多種不同的驅動方法來提升線性位移平台的效能。首先需要突破的基本限制是,在有限的結構中,邊界會產生反射波,因此會干擾傳遞波的形成。為了解決這問題,過往各國的團隊經過研究,開發出透過單一頻率產生鄰近兩共振頻來產生可任意改變方向的行進波,並藉以驅動壓電致動器。
此一方法藉由驅動介於兩相鄰共振頻之間的頻率來驅動,以求能在兩相鄰的正交模態進行疊合,進一步可在有限結構中產生行進波,而從振動理論可知,以正交模態展開疊合成外力激盪下之振動行為,每個模態有各自的加權函數,因此一般操作單頻雙模態激發之操作頻率若選在相鄰自然頻率之正中間頻率,不一定合適於此兩模態之疊加,並可能會因此降低操作之效率,並且在結構反應之增益值沒有在驅動共振頻時來顯著。 因此本研究提出突破以往限制的雙頻雙模態方式來驅動壓電致動器,透過操作在兩個共振頻率上產生極大增益值,再進而分析其電極的位置、驅動電壓與訊號之相位差來調控驅動效能之影響,以期達到優化行進波之產生,而此設計將可有效節能,可提升直線型行進波位移平台之效能,最終本論文以數值模擬及實驗架構來驗證此一創新設計理念,實驗成果可將載物移動,並且載物移動速率最高可達4.8mm/s,證實此次研究所提出創新方法是有可行性、有效性、和實用性。 It is reported that using the method of one-frequency-two-mode to drive a piezoelectric linear motor, the influence of nature resonance induced by the finite boundaries can be minimized. The structure of the piezoelectric linear motor is constructed by placing two piezoelectric actuators on a one-dimensional finite plate. A single driving frequency at the middle of two adjacent bending modes is used to drive these two piezoelectric actuators with a 90° phase difference, and a traveling wave can be generated. However, due to the driving frequency was not directly at the resonant frequency, the efficiency and traveling distance are relatively low. Based on our previous studies, it shows that the driving voltage and velocity of displacement has a linear relationship, and the size and location of actuators also can influence generated traveling waves. In this thesis, the method of two-frequency-two-mode is proposed and studied. Two adjacent bending modes are activated with a phase difference and a voltage ratio to generate traveling waves. Since the operating frequencies of the two actuators are at resonant frequencies, the efficiency can be very high. Our studied showed that the difference between native electrical impedance and mechanical impedance of the two adjacent resonant modes, the performance of the induced traveling waves can vary significantly. Furthermore, the total distance and profile of traveling waves also can be different. To understand this mechanism, we study the influence of two driving frequencies with different amplitude ratio and phase differences. Thus, the energy that falls into the two adjacent modes can adjust, and the ratio of vibrating amplitudes of these two modes can be controlled. It is demonstrated that the total traveling distance can be much enhanced by controlling the driving amplitude and phase difference between two actuators. The moving speed of object can reach 4.8 mm/s. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/70384 |
DOI: | 10.6342/NTU201803196 |
全文授權: | 有償授權 |
顯示於系所單位: | 應用力學研究所 |
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