Transcript Guided by Er. Deepak Ku. Sahoo Submitted by Susanta Sarkar Regd. 0901219210 Branch: EEE,7th Sem.

Guided by
Er. Deepak Ku. Sahoo
Submitted by
Susanta Sarkar
Regd. 0901219210
Branch: EEE,7th Sem
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INTRODUCTION
PIEZOELECTRIC NOTION
PIEZOELCRIC MOTOR NOTION
BASIC PRINCIPLE
CONSTRUCTION
TYPES
MAJOR APPLICATION
MERITS AND DEMERITS
CONLUSION
REFERENCE
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 by
inverse piezoelectric effect.
 This motor achieves high speed and drive
forces,while still permitting the moving part
to be positioned with high accuracy.
PIEZOELECTRIC NOTION
 Piezoelectricity – generation of voltage in response of
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mechanical stress.
The word is derived from the Greek piezein, which means
to squeeze or press.
This effect is also reversible.
Deformation is only 0.1 % of the original dimension.
Piezoelectric material- quartz(SiO2), barium titanate
(BaTiO3).
PIEZOELECTRIC MOTOR NOTION
 Change in shape of piezoelectric material when electric
field 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 the
moving part (in linear USM).
BASIC PRINCIPLE
 generation of gross mechanical motion through
the amplification and repetition of microdeformations 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 MHz
 Amplitude of the actuator motion – 20 to 200nm
BASIC PRINCIPLE
•The active 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 micromotion 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.
Construction
Fundamental construction of USM
Ultrasonic motor by barth
TYPES OF ULTRASONIC MOTOR
Ultrasonic
motor
Standing
wave
bidirectional
Traveling
wave
unidirectional
STANDING WAVE USM
Standing wave USM
 Representation u( x, t) = A coskx coswt
 It is also referred as vibratory coupler type or
wood pecker type.
Standing wave USM
 Low cost
 one vibration source
 Unidirectional
 High efficiency
TRAVELING WAVE USM
 Superposition of multiple standing wave
create a traveling wave.
 Representation of travelling wave
U(x ,p)= A cos(k x) cos(wt) + A cos(k x - 90)
cos (wt-90).
 Phase difference is 90 degree
Travelling wave USM
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 Requires two vibrating source
 Low efficiency.
BIDIRECTIONAL MOTOR
 For linear motion bidirectional drives are
required .
 More than two actuators are used.
 These actuators must have some phase
difference
 It can be obtained by superimposing to
oscillations in a single resonator.
 Stator is hybrid construction consisting of
several actuators.
MAJOR APPLICATION
 Camera auto focus lenses
 Driving fluid
 Watch motors and compact
paper handling.
 Optoelectronics area
 In micro surgery and sensor
scaning.
Merits
Demerits
 Low cost
 Use of high frequency
 High efficiency
power supply
 Less durability
 Drooping torque speed
characteristic.
 No magnetic
interference
 Compact size
 High power/weight
ratio.
CONCLUSION
 These motors are very advantageous.
 Electromagnetic interference is not there.
 It is in great demand in the area automation
and miniaturization.
 These motors are low cost
REFERENCE
 www.google.com
 www.yahoo.com
 www.slideworld.com
 www.pdf-searchengine.com
 www.ask.com
 http://www.americanpiezo.com/piezo_theory
/piezo_theory.pdf
THANK YOU