共查询到20条相似文献,搜索用时 15 毫秒
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A rotary ultrasonic motor using bending vibration transducers 总被引:1,自引:0,他引:1
Liu Y Chen W Liu J Shi S 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2010,57(10):2360-2364
A rotary ultrasonic motor using bending vibration transducers is proposed. In each transducer, two orthogonal bending vibrations are superimposed and an elliptical trajectory is generated at the driving foot. Typical output of the prototype is a no-load speed of 58 rpm and maximum torque of 9·5 Nm under an exciting voltage of 200 V(rms). 相似文献
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Zhu ML Lee SR Zhang TY Tong P 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2000,47(6):1561-1574
This paper proposes an analytical model of a rotary motor driven by an anisotropic piezoelectric composite laminate. The driving element of the motor is a three-layer laminated plate. A piezoelectric layer is sandwiched between two anti-symmetric composite laminae. Because of the material anisotropy and the anti-symmetric configuration, torsional vibration can be induced through the inplane strain actuated by the piezoelectric layer. The advantages of the motor are its magnetic field immunity, simple structure, easy maintenance, low cost, and good low-speed performance. In this paper, the motor is considered to be a coupled dynamic system. The analytical model includes the longitudinal and torsional vibrations of the laminate and the rotating motion of the rotor under action of contact forces. The analytical model can predict the overall characteristics of the motor, including the modal frequency and the response of motion of the laminate, the rotating speed of the rotor, the input power, the output power, and the efficiency of the motor. The effects of the initial compressive force, the applied voltage, the moment of rotor inertia, and the frictional coefficient of the contact interface on the characteristics of the motor are simulated and discussed. A selection of the numerical results from the analytical model is confirmed by experimental data. 相似文献
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V. M. Bogomol'nyi 《Measurement Techniques》1994,37(12):1412-1416
The electric field E in a poled dielectric is calculated numerically taking into account its electrical conductivity as a function of the driving frequency and the dielectric relaxation time. The conditions are determined for E to be independent of the driving frequency, stabilizing the characteristics of the transducers. Practical recommendations are given for choosing the electrophysical parameters of piezoelectric materials for infrared radiation modulators.Translated from Izmeritel'naya Tekhnika, No. 12, pp. 50–52, December, 1994. 相似文献
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By introducing equivalent boundary conditions, an analysis is made of the sensitive elements of radio wave measuring transducers in electrodynamic slow wave system. It is shown that the proposed method appreciably simplifies the development of sensitive elements with multilayer magnetodielectric screens, used, in particular, for measuring the magnetic permeability of ferrite components.Translated from Izmeritel'naya Tekhnika, No. 9, pp. 57–60, September, 1995. 相似文献
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Iula A Pappalardo M 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2006,53(7):1344-1351
In the present work, a traveling wave ultrasonic motor (TWUSM) is proposed. It is composed of an annular-shaped stator and two cone-shaped rotors that are pressed in contact to the borders of the inner surface of the stator. A rotating traveling wave has been generated in the stator by using as vibration generators two bolted Langevin transducers (BLT) opportunely shifted in space and in time. The vibrational behavior of the stator as well as the traveling wave generation has been simulated with the finite-element method (FEM) software. A prototype of the motor has been manufactured and experimentally characterized. It exhibits a static torque of about 0.8 N x m and a maximum angular speed of about 300 rpm. Possible variations of the present design aimed to increase output torque or minimize encumbrance are described and discussed. 相似文献
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旋转型行波超声电机定子的子结构模型研究 总被引:5,自引:0,他引:5
按照旋转型行波超声电机定子的结构特点将其划分为几个较简单的子结构,分别对其进行了动态特性分析,最后在子结构模态综合法的基础上建立了整个定子的分析模型。该模型可以很方便地计算电机定子的各阶模态,并且由于运用Guyan静力法将定子齿单元的刚度和质量凝聚到基体之上,不仅恰当地描述了齿对定子动态特性的影响,而且达到了缩减计算量的目的。通过算例和实验说明此理论模型是可行的,可用于电机系统性能预测和参数优化设计。 相似文献
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Tangpong XW Wickert JA Akay A 《Philosophical transactions. Series A, Mathematical, physical, and engineering sciences》2008,366(1866):811-827
A ring damper can be affixed to a rotating base structure such as a gear, an automotive brake rotor or a gas turbine's labyrinth air seal. Depending on the frequency range, wavenumber and level of preload, vibration of the base structure can be effectively and passively attenuated by friction that develops along the interface between it and the damper. The assembly is modelled as two rods that couple in longitudinal vibration through spatially distributed hysteretic friction, with each rod having periodic boundary conditions in a manner analogous to an unwrapped ring and disc. As is representative of rotating machinery applications, the system is driven by a travelling wave disturbance, and for that form of excitation, the base structure's and the damper's responses are determined without the need for computationally intensive simulation. The damper's performance can be optimized with respect to normal preload, and its effectiveness is insensitive to variations in preload or the excitation's magnitude when its natural frequency is substantially lower than the base structure's in the absence of contact. 相似文献
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Liu Y Liu J Chen W Shi S 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2012,59(5):981-989
A U-shaped linear ultrasonic motor using longitudinal vibration transducers with double feet was proposed in this paper. The proposed motor contains a horizontal transducer and two vertical transducers. The horizontal transducer includes two exponential shape horns located at the leading ends, and each vertical transducer contains one exponential shape horn. The horns of the horizontal transducer and the vertical transducer intersect at the tip ends where the driving feet are located. Longitudinal vibrations are superimposed in the motor and generate elliptical motions at the driving feet. The two vibration modes of the motor are discussed, and the motion trajectories of driving feet are deduced. By adjusting the structural parameters, the resonance frequencies of two vibration modes were degenerated. A prototype motor was fabricated and measured. Typical output of the prototype is no-load speed of 854 mm/s and maximum thrust force of 40 N at a voltage of 200 V(rms). 相似文献
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Modeling of a piezoelectric rotary ultrasonic motor 总被引:28,自引:0,他引:28
Hagood N.W. IV McFarland A.J. 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》1995,42(2):210-224
A piezoelectric rotary ultrasonic motor is modeled for the purpose of predicting, a priori, motor performance as a function of design parameters. The Rayleigh-Ritz assumed mode energy method is used to model the distributed piezoceramics and the traveling wave dynamics of the stator. Natural frequencies and modeshapes are obtained for a generally configured motor. Nonlinear normal and tangential interface forces between the rotor and stator are incorporated into the forcing function along with the linear piezoelectric forcing. Given the applied torque, applied axial loading, and piezo drive voltages as inputs to the model, general motor performance measures are obtained-namely speed, input power, output power, and efficiency. The approach presented here provides a general framework for modeling these motors as well as a design tool for optimizing prototypes with the added flexibility of allowing for a wide variety of geometries and materials 相似文献
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驻波管法测定材料的声阻抗是一种常用和可靠的方法.但一般它要一个移动的换能器,使能测出管中的驻波比.本文是用二个换能能器,可测出管内和管端的声阻抗以及其它声传输参量. 相似文献
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This analysis deals with the convective travelling wave instability appearing in a fluid medium at rest and contained between two horizontal rigid plates, subjected to the same sinusoidal temperature distribution, moving at a uniform speed and in the same direction. The temperature distribution is caused by travelling planar heat sources with a time harmonic output. A three-dimensional coordinate system is used and the small parameter in this problem represents the ratio between the buoyancy and inertial forces. For a finite, yet small , asymptotic expansions are assumed for the velocity, pressure, temperature and the Reynolds number. The mean motion generated by the Reynolds stresses is calculated separately. By keeping the Prandtl number fixed and by using long length and time scales, successive linearized perturbation equations are considered. Two successive amplitude equations are analyzed and their solution yields the mathematical form of these travelling waves, their group velocity and the elevation above the critical Reynolds number. 相似文献
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The standard Langevin equation is a first order stochastic differential equation where the driving noise term is a Brownian motion. The marginal probability density is a solution to a linear partial differential equation called the Fokker–Planck equation. If the Brownian motion is replaced by so-called -stable noise (or Lévy noise) the Fokker–Planck equation no longer exists as a partial differential equation for the probability density because the property of finite variance is lost. Instead it has been attempted to formulate an equation for the characteristic function (the Fourier transform) corresponding to the density function. This equation is frequently called the spectral Fokker–Planck equation.
This paper raises doubt about the validity of the spectral Fokker–Planck equation in its standard formulation. The equation can be solved with respect to stationary solutions in the particular case where the noise is Cauchy noise and the drift function is a polynomial that allows the existence of a stationary probability density solution. The solution shows paradoxic properties by not being unique and only in particular cases having one of its solutions closely approximating the solutions to a corresponding Langevin difference equation. Similar doubt can be traced Grigoriu's work [Stochastic Calculus (2002)]. 相似文献