USU ECE 5320 - Piezomotors Ultrasonic Motors

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Piezomotors “Ultrasonic Motors”OutlineReference ListPiezoelectric NotionsPiezoelectric Motor NotionsSlide 6Major ApplicationsSlide 8Basics PrinciplesSlide 10Slide 11Slide 12Slide 13USM PrototypesSlide 15Bi-directional linear standing wave USMSlide 17Rotary Ultrasonic MotorSlide 19Spherical ultrasonic motorSuppliers InformationPiezomotors “Ultrasonic Motors”Prepared by: Jaime FernandezDepartment of Electrical and Computer Engineering Utah State UniversityECE 5320 MECHATRONICSActuator TutorialOutline•Reference List•Piezoelectric Notions•Piezoelectric Motor Notions•Major Applications•Basics Principles•Major Applications•Major specificationsReference List•“Wikipedia”, http://en.wikipedia.org/wiki/Piezoelectricity•“Alexander D. Khazan”, Transducers and Their Elements, Prentice Hall PTR • “Robert H. Bishop”, Mechatronics Handbook, section 19.2•“Manfred Weber”, http://www.mmf.de/•“Shyh-Shiuh Lih, Yoseph Bar-Cohen”, Rotary Ultrasonic Motors Actuated By Traveling Flexural Waves, http://ndeaa.jpl.nasa.gov/nasa-nde/lommas/spie-usm97.htmPiezoelectric Notions•“Piezoelectricity is the ability of certain crystals to generate a voltage in response to applied mechanical stress. The word is derived from the Greek piezein, which means to squeeze or press. The piezoelectric effect is reversible in that piezoelectric crystals, when subjected to an externally applied voltage, can change shape by a small amount. The deformation, about 0.1% of the original dimension in PZT, is of the order of nanometers, but nevertheless finds useful applications such as the production and detection of sound, generation of high voltages, electronic frequency generation, and ultra fine focusing of optical assemblies.”•“In a piezoelectric transducer, the acceleration acts on the seismic mass that develops a force on piezoelectric quartz, or ceramic crystal, or on several crystals. The force causes charges on the crystals proportional to the acceleration.”“Wikipedia”, http://en.wikipedia.org/wiki/Piezoelectricity“Alexander D. Khazan”, Transducers and Their Elements, Prentice Hall PTR “Robert H. Bishop”, Mechatronics Handbook, section 19.2Piezoelectric Motor NotionsA piezoelectric motor or piezo motor is a type of electric motor based upon the change in shape of a piezoelectric material when an electric field is applied.The ultrasonic motor ( USM ) is a new type of solid state motor, which is driven by the ultrasonic vibration of a piezoelectric transducer. The ultrasonic vibration is transformed into output torque (in rotary USM) or thrust (in linear USM) by the friction between the stator and the rotor (in rotary USM) or the moving part (in linear USM). “Manfred Weber”, http://www.mmf.de/This new breed of motors has many excellent performances and features such as high torque, low speed, simple and compact structure with great variability in design, not interfering or being affected by magnetic field when in operation, power off self-brake, etc. The chief drawback of USM lies in the fatigue wearing of the stator due to the frictional driving mechanism.“Manfred Weber”, http://www.mmf.de/Major Applications •Camera auto focus lenses, •Watch motors and compact paper handling.•Medical application within micro-surgery and sensor scanning •Driving fluids •Optoelectronics area •Motion controlPiezo motors consists mainly of an electro-mechanical resonator and a rotor. The resonator transfer electric energy into small elliptical mechanical vibrations that forces the rotor to rotate due to friction between resonator tip and rotor. Piezoelectric motors have some very nice characteristics compared to traditional induction motors and in general they are characterized by a high torque at low angular velocity, silent operation, high positioning precision, simple mechanical construction and it induces no magnetic fields.Modeling and Control of a Standing Wave Piezo Electric Motor, Brian Andersen.Basics Principles•The general principle of the operation of ultrasonic motors is to generate gross mechanical motion through the amplification and repetition of micro-deformations of active material. The active material induces an orbital motion of the stator at the rotor contact points and frictional interface between the rotor and stator rectifies the micro-motion to produce macro-motion of the stator. Development of an Ultrasonic Motor as aFine-Orienting Stage Eko Purwanto, Member, IEEE, and Shigeki ToyamaThe active material, which is a piezoelectric material excites a traveling flexural wave within the stator that leads to elliptical motion of the surface particles. Teeth are used to enhance the speed that is associated with the propelling effect of these particles. The rectification of the micro-motion an interface is provided by pressing the rotor on top of the stator and the frictional force between the two causes the rotor to spin. This motion transfer operates as a gear leads to a much lower rotation speed than the wave frequency. Rotary Ultrasonic Motors Actuated By Traveling Flexural Waves, Shyh-Shiuh Lih, Yoseph Bar-Cohen, http://ndeaa.jpl.nasa.gov/nasa-nde/lommas/spie-usm97.htmA stator substrate is assumed to have a thickness, tS, with a set of piezoelectric crystals that are bonded to the back surface of the stator in a given pattern of poling sequence and location. The thickness of the piezoelectric crystals is tp. The total height, h, is the sum of the thickness of the crystals and the stators (bonding layer is neglected). The overall height of the stator is also allowed to vary with radial position. The outer radius of the disk is b and the inner hole radius is a. To generate traveling wave, the piezoelectric crystals poling direction is structured such that quarter wavelength out-of-phase is formed. This poling pattern is also intended to eliminate extension in the stator and maximize bending. The teeth on the stator are arranged in a ring at the radial position.Rotary Ultrasonic Motors Actuated By Traveling Flexural Waves, Shyh-Shiuh Lih, Yoseph Bar-Cohen, http://ndeaa.jpl.nasa.gov/nasa-nde/lommas/spie-usm97.htm•To generate a traveling wave within the stator two orthogonal modes are activated simultaneously. These modes are induced by constructing the drive piezoelectric actuators in a pattern of two poling sections that are bonded to the stator. Geometrical examination of this pattern shows that driving the two sections


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USU ECE 5320 - Piezomotors Ultrasonic Motors

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