https://scholars.lib.ntu.edu.tw/handle/123456789/62809
Title: | 含雙層壓電片振動子之超音波馬達動態分析 Dynamic Analysis of an Ultrasonic Motor with a Vibrator Having Double Layer Piezo Films |
Authors: | 林武辰 Lin, Wu-Chen |
Keywords: | 超音波馬達;古典平板理論;電彈理論;壓電效應;行進波;ultrasonic motor;classic plate theory;electroelastic theory;piezoelectric effect;traveling wave | Issue Date: | 2007 | Abstract: | 本研究提出環形雙層壓電片振動子之概念設計,以得到較單層壓電元件具有較大位移及速度之旋轉型行進波式超音波馬達。本文中之振動子受激振時,會產生行進波之振型。採用古典平板理論及電彈理論,建立振動子之振動模型,以解析解求得振動子之位移,並以等效彈簧阻尼系統建立振動子與轉子之接觸模型,利用庫倫摩擦定律,軸向方向為準靜力平衡,計算振動子與轉子接觸面間之正向力及摩擦扭矩,進而求得受到轉子及基座影響之振動子之軸向位移,與轉子之轉速、扭矩與功率。最佳化設計採用隨機跳躍法,以振動子與轉子之間能量轉換效率作為目標函數,得到最佳化之馬達尺寸及輸入參數。數值方法採用四階朗吉庫塔法,並且建構電腦程式,以獲得轉子暫態與穩態之轉速、扭矩與功率。由計算結果得知行進波振幅與振動子輸入電壓成正比,而轉子預負載增大時,行進波振幅變小,且影響會隨預負載增加而趨於平緩。摩擦扭矩會隨振動子與轉子之接觸區域增加而變大,於接觸區域內,振動子切向速度小於轉子切向速度時,會產生反向之摩擦扭矩,而制動轉子,使得轉子之磨耗增加,而降低效率。最佳化之結果得到在振動子輸入電壓為110V,預負載為127 N,驅動頻率為26 kHz,轉子轉速為1.24 rad/s,最大阻抗扭矩為0.56 Nm,能量轉換效率理論值為100 %。 This study proposes the conceptual design of a ring-type vibrator with double layer piezo films for a rotary traveling wave ultrasonic motor to achieve the larger displacement and faster speed compared with a single layer piezo film. When the vibrator is excited, it generates the traveling wave to rotate the rotor. The vibratory model of the vibrator is generated by utilizing the classic plate theory and the electroelastic theory to obtain the analytical solution of the vibrator displacement. A contact model of the vibrator and the rotor is generated by using the equivalent system and the Coulomb’s friction law to calculate the normal force and the friction torque on the contact surfaces of the vibrator and the rotor. The axial displacement of the vibrator affected by the rotor and the base of the vibrator, the rotational speed, the torque and the power of the rotor are calculated. The random jumping method is used for optimization of the dimensions and the input parameters of the ultrasonic motor. The objective function is the energy conversion efficiency between the vibrator and the rotor. The 4th order Runge-Kutta method is used and a computer program is generated to obtain the rotational speed, the torque and the power in the transient state and the steady state. The calculated results show that the amplitude of the traveling wave is proportional the the input voltage. As the preload increases, the amplitude of the traveling wave and the effect are decreased. The friction torque increases when the contact area between the vibrator and the friction coat increases. When the tangential speed of the vibrator is slower than that of the rotor, the friction torque will be inversed to reduce the speed of the rotor. The wear of the rotor increases and the efficiency is decreased. The calculated optimal results show that the input voltage is 110 V, the preload is 127 N, and the rotational speed is 1.24 rad/s, the maximum impedance torque is 0.56 Nm, the energy conversion efficiency is 100 %. |
URI: | http://ntur.lib.ntu.edu.tw//handle/246246/61381 | Other Identifiers: | zh-TW |
Appears in Collections: | 機械工程學系 |
File | Description | Size | Format | |
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ntu-96-R93522628-1.pdf | 23.53 kB | Adobe PDF | View/Open |
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