Download or read book Modeling and Testing of Ultrasonic Motors written by Philippe Bouchilloux and published by . This book was released on 2001 with total page 223 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ultrasonic Motors written by Chunsheng Zhao and published by Springer Science & Business Media. This book was released on 2011-10-23 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive tutorial on ultrasonic motors for practicing engineers, researchers and graduate students. "Ultrasonic Motors: Technologies and Applications" describes the operating mechanism, electromechanical coupling models, optimization design of structural parameters, testing methods, and drive/control techniques of various ultrasonic motors and their applications. Dr. Chunsheng Zhao is a professor at Nanjing University of Aeronautics and Astronautics (NUAA) where he is Director of the Precision Driving Laboratory at NUAA. He is a member of the Chinese Academy of Science, and holds 54 patents in China and published more than 400 papers in the field of piezoelectric ultrasonic motors.

Download or read book Modeling of an Ultrasonic Rotary Motor written by Carlos Cuauht Cuevas Gutierrez and published by VDM Publishing. This book was released on 2008 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ultrasonic motors are a new type of actuators that use mechanical vibrations of its stator to drive the rotor through frictional forces between the interface of the stator and rotor. Ultrasonic motors have recently been attracting considerable attention in industrial applications where high precision, fast response and high torque at low speed are desirable. In contrast to traditional electromagnetic motors, ultrasonic motors provide larger torque to volume ratio, silent operation, and compact design. Furthermore, its operation is not affected by electromagnetic fields, and the motor shaft remains braked when the power supply is removed. The commercial development of ultrasonic motors, however, has been limited primarily due to lack of complete models for the purpose of control. Consequently, the development of an accurate model based on the physical structure is extremely vital for controllers development. The present dissertation proposes a comprehensive model for the purpose of predicting the motor performance. A lumped-mass model of the stator is proposed to consider the coupling effects on the stator based on the flexibility influence coefficients, which are estimated from a finite element method. Moreover, the stator natural frequencies are obtained using modal analysis. Nonlinear tangential interface forces between the rotor and stator are incorporated into the driving torque function. A rotor model based on the Stribeck effect, Coulomb and viscous friction is also incorporated to describe the friction torque associated with the motor response. An extensive series of experiments have been designed together with a state-of-the-art test bench built at the laboratory of Concordia University. The validity of the proposed model was examined by comparing the model results with the measured data under different excitation conditions. The lumped-mass model is able to reproduce reasonably well the stator displacements and the excited modes when it is driven at different frequencies as a result of the stiffness coupling. Several rotor model parameters are identified by using the experimental data and a weighted error minimization function. From the results obtained in the present study, it is concluded that the proposed USM model can reproduce reasonably well the motor behavior to different excitations inputs such as step, ramp and harmonic excitations as well as the torque-speed characteristics. It is important to note that the developed model shows torque-speed hysteresis behavior, which has not been reported in literature. To experimentally confirm this new phenomenon, extensive experimental tests have been conducted to identify the torque-speed characteristics on the ultrasonic motor. It has been observed from experiments a clear torque-speed hysteresis in the ultrasonic motor attributed mainly to the friction drive principle at the contact interface. This behavior, however, has not been addressed previously. It is suggested that the lack of an appropriate instrumentation together with inadequate models have made very difficult to describe this phenomenon. On the other hand, the torque-speed hysteresis exhibits a high asymmetric behavior at low speed as a result of the friction torque produced by the Stribeck effect.

Download or read book Modeling and Experimental Validation of an Ultrasonic Rotary Motor written by Carlos Cuauhtémoc Cuevas Gutiérrez and published by . This book was released on 2007 with total page 466 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ultrasonic motors are a new type of actuators that use mechanical vibrations of its stator to drive the rotor through frictional forces between the interface of the stator and rotor. Ultrasonic motors have recently been attracting considerable attention in industrial applications where high precision, fast response and high torque at low speed are desirable. In contrast to traditional electromagnetic motors, ultrasonic motors provide larger torque to volume ratio, silent operation, and compact design. Furthermore, its operation is not affected by electromagnetic fields, and the motor shaft remains braked when the power supply is removed. The commercial development of ultrasonic motors, however, has been limited primarily due to lack of complete models for the purpose of control. Consequently, the development of an accurate model based on the physical structure is extremely vital for controllers development. The present dissertation proposes a comprehensive model for the purpose of predicting the motor performance. A lumped-mass model of the stator is proposed to consider the coupling effects on the stator based on the flexibility influence coefficients, which are estimated from a finite element method. Moreover, the stator natural frequencies are obtained using modal analysis. Nonlinear tangential interface forces between the rotor and stator are incorporated into the driving torque function. A rotor model based on the Stribeck effect, Coulomb and viscous friction is also incorporated to describe the friction torque associated with the motor response. An extensive series of experiments have been designed together with a state-of-the-art test bench built at the laboratory of Concordia University. The validity of the proposed model was examined by comparing the model results with the measured data under different excitation conditions. The lumped-mass model is able to reproduce reasonably well the stator displacements and the excited modes when it is driven at different frequencies as a result of the stiffness coupling. Several rotor model parameters are identified by using the experimental data and a weighted error minimization function. From the results obtained in the present study, it is concluded that the proposed USM model can reproduce reasonably well the motor behavior to different excitations inputs such as step, ramp and harmonic excitations as well as the torque-speed characteristics. It is important to note that the developed model shows torque-speed hysteresis behavior, which has not been reported in literature. To experimentally confirm this new phenomenon, extensive experimental tests have been conducted to identify the torque-speed characteristics on the ultrasonic motor. It has been observed from experiments a clear torque-speed hysteresis in the ultrasonic motor attributed mainly to the friction drive principle at the contact interface. This behavior, however, has not been addressed previously. It is suggested that the lack of an appropriate instrumentation together with inadequate models have made very difficult to describe this phenomenon. On the other hand, the torque-speed hysteresis exhibits a high asymmetric behavior at low speed as a result of the friction torque produced by the Stribeck effect.

Download or read book Modeling Design Development and Testing of a Piezoelectric Traveling Wave Rotary Ultrasonic Motor for Space Applications written by Andrew John McFarland and published by . This book was released on 1995 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modeling of the Stator of Piezoelectric Traveling Wave Rotary Ultrasonic Motors written by Valentin Bolborici and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis is concerned with the modeling of the stator of a piezoelectric traveling wave rotary ultrasonic motor. Existing models for piezoelectric traveling wave rotary ultrasonic motors are either too complicated to be used in motor control or do not reflect the real behavior of the motor and are of limited use in developing a controller for the motor. Finite Element methods have been used in the past to examine the properties of piezoelectric structures however, the Finite Volume Method has always been ruled out without justification. The main goal of this thesis is to provide a Finite Volume modeling approach for the stator of the piezoelectric traveling wave rotary ultrasonic motor taking into account the basic theoretical principles from piezoelectricity and structural mechanics. This model can in future be extended to develop a complete model of the motor in addition to other piezoelectric structures. The Finite Volume Method is shown to have the following specific advantages over the Finite Element Method especially for structures with simple geometries: 1. the Finite Volume Method respects the PDEs conservation law structure due to the fact that the fluxes are conserved between cells/domains/subregions, 2. the Finite Volume Method involves only surface integrals thus making it easier to implement a rotor-stator contact model as the contact mechanism occurs at the boundary of the stator, and 3. the Finite Volume Method yields a system of ODEs that more intuitively map onto circuit simulation software. The Finite Volume Method is initially used to model a simple piezoelectric plate. A corresponding circuit of the piezoelectric plate model, based on the Finite Volume Method, is generated. Two additional but more complex models are considered: one for a unimorph plate and one for the stator of an ultrasonic motor. The modeling results obtained with the Finite Volume Method are validated by comparing them with the results obtained with Finite Element simulations performed with COMSOL. Two test platforms designed to test and validate the Finite Volume and COMSOL results for the simple piezoelectric plates and piezoelectric traveling wave rotary ultrasonic motors are also presented in this thesis.

Download or read book Modeling and Validation of Ultrasonic Motor written by Nikhil Khadilkar and published by . This book was released on 2004 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modeling of Piezoelectric Traveling Wave Ultrasonic Motors written by Jayakumar Chandrasekar and published by . This book was released on 1996 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modeling of the Stator of Piezoelectric Traveling Wave Rotary Ultrasonic Motors written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modeling of Piezoelectric Traveling Wave Rotary Ultrasonic Motors with the Finite Volume Method written by Ivan Arturo Renteria Marquez and published by . This book was released on 2016 with total page 129 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Finite Element Modeling and Optimization of Tube Shaped Ultrasonic Motors written by and published by . This book was released on 2003 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent developments in ultrasonic motor design have demonstrated that small size tube-shaped motors could be fabricated at low cost. Motors with diameters between 15 and 2.5mm have been fabricated and tested. The performance evaluation of these motors is still in progress, but have already shown promising results: the smallest ones exhibit no-load speeds in the range of 70rad/s and blocked torgues close to 0.9mNdotm. In this paper, we review the operating principle of these devices and several implementation examples. Then, we show how the finite element method (ATILA) can be used, in combination with genetic optimization procedures, to design tube-shaped motors in various dimensions and for different performance objectives. Several design examples are presented and discussed.

Download or read book The Dynamics of Combined Axial torsional Standing wave Ultrasonic Motors written by Daniel Kuang-Chen Liu and published by . This book was released on 2009 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt: Piezoelectric ultrasonic motors have the potential to enable important applications such as endovasular surgical micro-robots due to their high torque and power density at the 0.1-1 mm diameter range. A type of ultrasonic motor that is suitable for miniaturization is the combined axial-torsional standing-wave (CATS) ultrasonic motor that generates the CATS stator motionvia pretwisted beam vibration converters.The operation of the motor involves (1) the generation of an ellipse-like stator tip trajectory when the pretwisted-beam stator is excited to vibrate in a CATS motion by a piezoelectric transducer, and (2) the transfer of frictional torque when the rotor is pressed against the stator tip. To gain a better understanding of the CATS ultrasonic motor, centimeter-scale prototypes were fabricated and tested to determine the characteristics of the motor design. Theoretical models of the pretwisted beam stator and the torque transfer mechanism were also investigated to help us predict the effects of various design parameters.The axial and torsional resonance frequencies of the pretwisted-beam stator needs to be matched for an effcient generation of the CATS stator motion. To help designers select the right analysis method for the design process, we investigated the validity of common pretwisted beam theories that assume the warping function of a pretwisted beam is locally identical to that of a prismatic beam. Through a scaling analysis of the equations governing the warping function of pretwisted beams -- derived using semi-inverse method and Hamilton's principle -- we obtained a set of criteria for checking the validity of the assumption. These criteria allow us to determine at what geometries the use of prismatic warping function will result in poor predictions of the axial resonance frequency and that alternative modelling methods are needed.Existing models of CATS motors ignore the vertical displacement of the rotor, predicting periodic behaviours that are contrary to the apparently random oscillations observed in the motor's steady-state operation. Our incorporation of the rotor's vertical motion results in a bouncing-disk model that explains various behaviours of the motor prototype, including the oscillations in the transient speed-time curve, and the effect of preload on stall torque and steady-state speed. The nonlinear dynamical system formed by the bouncing disk model shows that different stator trajectories and interface properties can give rise to complex phenomena such as period doubling bifurcation, chaos, and extremely long period "chattering orbits". Knowledge of the location and basins of attraction for these orbits gives us detailed understanding of the motor's behaviour that will help designers improve the performance of CATS ultrasonic motor.

Download or read book Control of Travelling Wave Ultrasonic Motors written by Sheung-Wai Chung and published by Open Dissertation Press. This book was released on 2017-01-27 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "Control of Travelling-wave Ultrasonic Motors" by Sheung-wai, Chung, 鍾尚威, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of thesis entitled Control of Travelling-wave Ultrasonic Motors submitted by CHUNG, Sheung Wai for the degree of Doctor of Philosophy at the University of Hong Kong in April 2006 A traveling-wave ultrasonic motor (TUSM) converts electricity into mechanical motion using piezoelectric effect. Generally two AC sinusoidal voltages with finite phase difference are employed to produce a continuous, time-varying bending of the stator. Such bending forms a traveling-wave along the surface of the stator. Since the rotor is hard pressed to the stator by a pressure disc, it is driven into rotation. The TUSM features a high holding torque. It offers a high torque at low speed characteristics. Its response is fast and it is much more than the traditional DC servomotor. Since it utilizes piezoelectric effect, there is no electromagnetic interference. Although the TUSM is very suitable for many mechatronic applications, its speed exhibits nonlinear response to controllable inputs. Such peculiarity presents a significant challenge for servo control using the TUSM. Different approaches of modeling have been adopted. These include equivalent circuit analysis, analytic approaches and finite element analysis. Unfortunately, they are either too complex or computationally intensive for controller design and simulation. In consequence, various empirical controllers have been employed. The first objective of this project is to develop a practical model of TUSM for control purposes. It relates the controllable inputs to the output torque of the TUSM. The second objective is to utilize this model to develop various modes of torque control, thus demonstrating its effectiveness. Both passive compliance and active speed controls are developed. Passive compliance control includes both the self-locking torque control and the reacting torque control. Neurofuzzy control and a practical model-based control have been explored for active speed control. Hence, all the control strategies which are essential for a robot manipulator are available, allowing TUSM to be deployed to it. A digital signal processing (DSP) based control system has been developed for experimental purpose. It consists of a DSP microcontroller, a power electronic drive, a TUSM and an optical encoder. The microcontroller provides two trains of PWM signals with variable frequency and duty ratio to the drive. The frequency expands the controllable speed span and the duty ratio offers a partial linear relationship to the motor torque. Through resonance, the drive converts a dc voltage into two sinusoidal voltages with finite phase difference. They are required to drive the TUSM. The optical encoder provides speed feedback to the microcontroller. This DSP-based system can therefore readily be deployed for standalone embedded mechatronic system. Experiments have demonstrated the effectiveness of self-locking torque and reacting torque control. Superior performance in tracking and disturbance rejection is also observed in both neurofuzzy and practical model-based controls. An abstract of exactly 419 words Signed ________________ Chung Sheung Wai DOI: 10.5353/th_b3689003 Subjects: Ultrasonic motors Servomechanisms

Download or read book Design of a Linear High Precision Ultrasonic Piezoelectric Motor written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: To understand the operating principles of linear ultrasonic piezoelectric motors, a motor made by Nanomotion Ltd. was examined and a model of the driving process was developed. A new motor has been designed that uses the same driving process but improves resolution, speed, efficiency and especially controllability. All designs involve at least two independently driven piezoelectric elements, one generating the normal load at the interface and the second generating the tangential driving force. The greatest challenges in developing this motor are 1) the actuator needs to have two different mode shapes at nearly the same frequency and 2) each mode shape must be exclusively excited by one actuator and not by the other. The quality of the operation of the motor directly depends on how well the excitation of both vibrations can be separated. Finite element analysis (FEA) has been used to model the actuator and predict the dynamic properties of a future prototype. The model includes all significant features that have to be considered such as the anisotropy of the piezoelectric material, the exact properties and the dimensions of the actuators (including all joints). Several prototypes have been built, and the resulting mode shapes and natural frequencies have been measured and compared to the computer models. The design concepts as well as the modeling techniques have been iteratively improved. Open loop testing has shown that the motor generates slideway motion such that the steady state slideway velocity is proportional to the excitation voltage. To fully characterize the motor and to demonstrate its full potential for positioning tasks, the motor has been tested in a closed loop control system. Despite saturation of the control input and nonlinearities in dynamics of the motor-slideway system, it was shown that a simple feedback control system using proportional gain or proportional-integrating control algorithms can be used to achieve a stable responsive positioning sy.

Download or read book Applications of ATILA FEM software to smart materials written by S.-J. Yoon and published by Elsevier Inc. Chapters. This book was released on 2012-11-27 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Piezoelectric ultrasonic motors offer many advantages such as high retention being very controllable, high torque at low speed, light weight, simple structure and no electromagnetic field induction compared with the conventional electromagnetic motors. These advantages have helped to expand the application fields where precise position control and rotational/linear motions can be utilized. One of the most remarkable features of the compact ultrasonic motor is that it has higher design flexibility compared with that of the conventional electromagnetic motors whose efficiency significantly decreases with miniaturization. In order to build a novel ultrasonic motor for a specific purpose, it is essential to examine the structural design and the electrical and mechanical properties prior to preparing a real motor. The ATILA simulation tool offers useful information related to the performance for a designed piezoelectric ultrasonic motor. A real motor can therefore easily be manufactured with minimized trial and error. In this chapter, two types of tiny motors are presented, including the process of ATILA simulation and the fabrication of ultrasonic piezoelectric motors.

Download or read book Ultrasonic Nondestructive Testing of Inhomogeneous Isotropic and Anisotropic Media Modeling and Imaging written by Chinta, Prashanth Kumar and published by kassel university press GmbH. This book was released on 2013-01-01 with total page 173 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis discusses ultrasonic testing by means of numerical modeling and image reconstruction techniques using elastic and acoustic wave fields. Numerical modeling of elastic waves (part one of the thesis) is used to understand the elastic wave scattering due to material defects and the propagation of surface waves in inhomogeneous isotropic and anisotropic media, with special emphasis on transversely isotropic and orthotropic media. Different imaging techniques (part two of the thesis) are investigated to develop a software, implemented in Matlab, which can give imaging results immediately after the measurement almost in real time as it can read and process the data obtained directly from the measurement. Acoustic wave scattering using analytical techniques and imaging techniques based on Radon transform are investigated. The data obtained from the Radon transform are subjected for imaging utilizing the filtered back projection algorithm and the Fourier slice theorem. The fundamentals of elastic wave propagation in solids are extensively elaborated. The point source synthesis to compute the Green’s functions for anisotropic media and the plane wave synthesis to compute slowness, phase and group velocity surfaces are studied. The elastic integral equations for the so called stretched coordinate system are derived. Based on these equations the numerical tool ’Three-dimensional Elastodynamic Finite Integration Technique’ (3D-EFIT) has been enhanced to treat not only isotropic media but also anisotropic media. For fast computation, the 3D-EFIT code using the Message Passing Interface (MPI) is used by which processing on massive parallel computers is made possible. In 3D-EFIT the Convolutional Perfectly Matched Layers (CPML) can also be applied to absorb the elastic body waves as well as the surface and evanescent waves. 3D-EFIT for homogeneous anisotropic media is validated by comparing computed Green’s functions with an analytical solution. After the validation, the applications of EFIT such as elastic wave modeling in inhomogeneous austenitic steel welds and inhomogeneous orthotropic wooden structures are presented. The results of the 2D-EFIT and 3D-EFIT modeling are compared against measurements performed at Federal Institute for Materials Research and Testing (BAM). After the modeling part of the thesis, inverse scattering techniques for fast imaging of inhomogeneities are studied. For three-dimensional imaging of defects in concrete, the Synthetic Aperture and Focusing Technique (SAFT) and Fourier Transformed Synthetic aperture Focusing Technique (FT-SAFT) are applied to data measured using a transducer array. The seismic Dip-Moveout (DMO) method has been utilized to convert measured bistatic data into monostatic data. A special treatment of SAFT as a technique for back propagation of the wave fields using time reversal, utilizing the knowledge of the geometry, is presented. Finally, time domain anisotropic SAFT (AnSAFT) is studied for image reconstruction of defects in inhomogeneous geometry with orthotropic crystal structure of the embedding medium.

Download or read book Traveling Wave Ultrasonic Motor written by and published by . This book was released on 2004 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: