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PREPARED BY:-ABU SAIKH OSSIULLAHELECTRICAL ENGINEERING DEPARTMENTROLL NO:-08119016059SILIGURI INSTITUTE OF TECHNOLOGYWEST BENGAL UNIVERSITY OF TECHNOLOGY


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1. INTRODUCTION2. PIEZOELECTRIC NOTION3. PIEZOELCRIC MOTOR NOTION4. BASIC PRINCIPLE5. CONSTRUCTION6. TYPES7. MAJOR APPLICATION8. MERITS AND DEMERITS9. CONLUSION10. REFERENCE


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INTRODUCTION

It has been known for more than 30 years.The first ultrasonic motor was introduce by

v.v lavrinko in 1965.Conversion of electric energy into motion byinverse piezoelectric effect.

This motor achieves high speed and driveforces,while still permitting the moving partto be positioned with high accuracy.


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P IEZOELECTRIC NOTION

Piezoelectricity generation of voltage in response of mechanical stress.

The word is derived from the Greek piezein, which meansto squeeze or press.

This effect is also reversible.

Deformation is only 0.1 % of the original dimension.

Piezoelectric material- quartz(SiO2), barium titanate(BaTiO3).


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P IEZOELECTRIC MOTOR NOTION

C hange in shape of piezoelectric material when electricfield is applied.

It can be abbreviated as USM.

It is driven by ultrasonic vibration of 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 themoving part (in linear USM).


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BAS IC P RINCI P LE

generation of gross mechanical motion throughthe amplification and repetition of micro-deformations of active material.The active material induces an orbital motion of the stator at the rotor contact points .frictional interface between the rotor and stator rectifies the micro-motion to produce macro-motion of the ROTOR.Working frequency-20 KHz to 10 MHzAmplitude of the actuator motion 20 to 200nm


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BAS IC P RINCI P LE

The active material excites a travelingflexural wave within the stator thatleads to elliptical motion of the surface

particles.Teeth are used to enhance the speed

that is associated with the propellingeffect of these particles.The rectification of the micro-motion

an interface is provided by pressing therotor on top of the stator and thefrictional force between the two causesthe rotor to spin.


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Construction

Fundamental construction of USM


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Ultrasonic motor by barth


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TYP ES OF ULTR AS ONIC MOTOR

Ultrasonicmotor

Standingwave

bidirectional unidirectional

Travelingwave


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S TANDING WAV E U S M


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S tanding wave U S M

Representation u( x, t) = A coskx coswtIt is also referred as vibratory coupler type or

wood pecker type.


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S tanding wave U S M

Low costone vibration source

UnidirectionalHigh efficiency


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TRAV ELING WAV E U S M

Superposition of multiple standing wavecreate a traveling wave.

Representation of travelling waveU(x ,p)= A cos(k x) cos(wt) + A cos(k x - 90)

cos (wt-90).

Phase difference is 90 degree


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Travelling wave U S M

Requires two vibrating sourceLow efficiency.


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BIDIRECTION AL MOTOR

For linear motion bidirectional drives arerequired .More than two actuators are used.These actuators must have some phasedifference

It can be obtained by superimposing tooscillations in a single resonator.Stator is hybrid construction consisting of several actuators.


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MAJ OR APP LIC ATION

C amera auto focus lenses

Driving fluid

Watch motors and compact paper handling.

Optoelectronics area

In micro surgery and sensor scaning.


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Merits Demerits

Low costHigh efficiency

No magneticinterferenceCompact sizeHigh power/weightratio.

Use of high frequencypower supply

Less durabilityDrooping torque speedcharacteristic.


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CONCLUS ION

These motors are very advantageous.

Electromagnetic interference is not there.It is in great demand in the area automationand miniaturization.

These motors are low cost


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REFERENCE

www.google.comwww.yahoo.com

www.slideworld.comwww.pdf-searchengine.comwww.ask.com

http://www.americanpiezo.com/piezo_theory/piezo_theory.pdf


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THANK YOU

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