1. PREPARED BY:-
CHANDAN BEHERA
ELECTRICAL ENGINEERING DEPARTMENT
REGISTRATION NO:-0901106167
COLLEGE OF ENGINEERING & TECHNOLOGY
BHUBANESWAR

2. CONTENTS
1. INTRODUCTION
2. ELECTROSTICTION NOTION
3. POLING
4. ULTRASONICMOTOR NOTION
5. EQUATIONS
6. BASIC PRINCIPLE
7. CONSTRUCTION
8. PARTS OF ULTASONIC MOTOR
9. TYPES OF ULTRASONIC MOTOR
10. DRIVER CIRCUIT OF ULTRASONIC MOTOR
11. CONTROL TECHNIQUE OF ULTRASONIC MOTOR
12. MAJOR APPLICATION
13. ADVANTAGES & DISADVANTAGES
14. CONLUSION
15. REFERENCE

3. INTRODUCTION
 The first ultrasonic motor was developed by
V.V lavrinko in 1965.
 Conversion of electric energy into motion by
inverse piezoelectric effect.
 In this tpye of motor efficiency is
insensitive to size,& these are superior in
the mm-sized motor area.

4. ELECTROSTICTION NOTION
 Inverse piezoelectricity – generation of mechanical stress
in response to electric voltage.
 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),PZT(Lead-Zirconium-Titanium).

5. HOW IT OCCURS??
 When voltage is applied across the crystal, the atoms
experience electrcal pressure.
 So they move to rebalance themselves, & thus
deformation is produced.
 If the voltage is applied in the direction of poling voltage
the material will elongate & its diameter reduces else
length decreases & diameter increases.
 If AC is applied then the material will lengthen & shorten
cyclically, at the frequency of applied voltage.

6. POLING
 It is process of polarization of the
piezoelectric material.

7. EQUATIONS
 The relationships between an applied voltage & the
corresponding increase or decrease in a piezoelectric
ceramic element's thickness, length, or width are:
Δh = d33v
S = d33E
Δl / l = d31E
Δw / w = d31E
where l: initial length of ceramic element
w: initial width of ceramic element
Δh: change in height (thickness) of ceramic element
Δl: change in length of ceramic element
Δw: change in width of ceramic element
d31,d33: piezoelectric charge constants in different
direction
V: applied voltage
S: strain (change in height / original height of element)
E: electric field

8. ULTRASONICMOTOR NOTION
 It is named so ,as it uses voltage of frequency higher than
20kHz.
 It is based on inverse piezoelectricty.
 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).

9. BASIC PRINCIPLE
 Generation of 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 .
 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

10. CONSTRUCTION

11. PARTS OF ULTRASONIC MOTOR
 The Stator part transmits vibration.
 Stator consists of:
The Piezo-Electric Ceramics which generate
vibration.
The Stator metal which makes vibration
amplify.
The Friction material which contacts with a
rotor.
 The Rotor which is a rotation part.
 The Shaft which transmits rotation.
 The Bearing.

12. WORKING
•If voltage is made to apply to piezo-electric ceramics, the shape
of piezo-electric ceramics will be changed or distorted. The
modification amplifies and spreads with stator metal, and
generates a traveling wave on the surface of stator metal.
•Here, the stator metal touches the rotor only at each peak of a
traveling wave, and each of that peak carries out elliptical
movement. A rotor rotates in response to the influence of the
elliptical movement.
•The direction of movement of this ellipse is in accordance to the
direction which a traveling wave follows. And a rotor rotates in the
direction contrary to a traveling wave under the influence.
•So, When a traveling wave progresses in the clockwise direction
(CW) on the circumference of a stator, each peak of the traveling
wave in contact with a rotor carries out elliptical movement in the
clockwise direction (CW).And the rotor in contact with the peak of
the wave rotates in the counterclockwise direction (CCW).By
controlling the speed and direction of this traveling wave, control
of an Ultrasonic Motor is possible

13. TYPES OF ULTRASONIC MOTOR
ULTRASONIC
MOTOR
STANDING TRAVELLING
WAVE TYPE WAVE TYPE
LINEAR ROTARY LINEAR ROTARY
MOTOR MOTOR MOTOR MOTOR

14. STANDING WAVE USM
 Representation u( x, t) = A coskx coswt
 It is also referred as vibratory coupler type or
wood pecker type.
 A vibrator is connected to the piezoelectric
driver,it produces bending, so its tip produces
flat elliptical motion to drive the rotor.

15. LINEAR TYPE STANDING WAVE USM
 Rectangular plate
ultrasonic motor.
 Resonant frequency-
98kHz.
 Efficiency-65%
 Applications-
card or paper senders.

16. ROTATING TYPE STANDING WAVE USM
 Torsional coupler
ultrasonic motor.
 Provides high speed
than linear motors
because of high
frequency (160kHz)&
amplified vibration.
 Provides speed of
1500 rpm, torque of
0.08 Nm & efficiency
of 80%.

17. STANDING WAVE USM
 Low cost
 one vibration source
 High efficiency
 Unidirectional

18. TRAVELING WAVE USM
 Superposition of multiple standing wave
create a traveling wave.
 Representation of travelling wave
U(x ,t)= A cos(k x) cos(wt) + A cos(k x - 90)
cos (wt-90).
 Phase difference is 90 degree

19. LINEAR TYPE TRAVELLING WAVE USM
 Linear motor using
bending vibration.
 Consists of two
piezoelectric vibrators
installed at both the
ends.
 Load resistance is
adjusted for perfect
travelling wave.

20. ROTARY TYPE TRAVELLING WAVE USM
 Two voltage sources are
used to produce
travelling wave.
 Vibrations of the
piezoelectric material is
amplified by the stator
teeths.
 Due to frictional forces
rotor rotates.
 Resonant frequency-
46kHz.

21. TRAVELLING WAVE USM
 Requires two vibrating source.
 Controllable in both direction.
 Silent operation, so suitable to video cameras
with microphone.
 Thinner design, leading to space saving.
 Low efficiency.

22. EQUIVALENT CIRCUIT OF USM
STATOR
 Cd is the capacitance due to
the dielectric property of
piezo crystal i.e tank
capacitance.
 Rm,Cm,Lm are the
resistance ,capacitnce &
inductance of stator.
 Their combined impedance
is given by
( +1/ + ).

23. DRIVER CIRCUIT OF USM

24. DRIVER CIRCUIT OF USM
 Nref and Uref are the given value of rotating speed
and amplitude of driving voltage, respectively.
 An optoelectric encoder, E, is used to measure the
rotating speed of ultrasonic motor.
 1 ∼ 8 are power MOSFETs, T1 and T2 are
transformers, and L1 and L2 are series
compensating inductances.
 PWM1~PWM8 are the PWM control signals
for 1 ∼ 8.
 DSP is used to implement the control strategies &
CPLD is used to produce the phase-shift PWM
control signals PWM1 ~ PWM8 for H-bridge.

25. CONTROL TECHNIQUE OF USM
 PWM control is used.
 Motor is operated at
resonance
frequency(low
impedance) to reduce
losses & to reduce
pressure on
piezoelectric material.
 Various control
methods are :

26. MAJOR APPLICATION
 Camera auto focus lenses
 Watch motors and compact
paper handling.
 Conveying machine parts
 In micro surgery and sensor
scaning.

27. ADVANTAGES DISADVANTAGES
 Low cost  Use of high frequency
 High efficiency power supply
 No magnetic  Less constancy
interference  Drooping torque
 Compact size speed characteristic
 High torque/weight  Supppression of heat
ratio is required
 Energy saving

28. CONCLUSION
 These motors are advantageous.
 Electromagnetic interference is not there.
 It is in great demand in the area of
automation & miniaturiztion.
 Energy efficient.
 Light weight & compact size

29. ANY QUERIES??

30. 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

31. THANK YOU ALL