2. TABLE OF CONTENT
INTRODUCTION.
PIEZOELECTRIC EFFECT.
STRUCTURE OF ULTRASONIC MOTOR.
WORKING OF ULTRASONIC MOTOR.
ADVANTAGES OF USM OVER EM MOTOR.
DISADVANTAGES OF USM.
MAJOR APPLICATIONS OF USM.
CONCLUSION.
REFERENCES.
ADDITIONAL INFO.
3. INTRODUCTION
• It has been known for more than 30year.
• the first ultrasonic motor was introduced by V.V.
Lavrinko in 1965.
• An ultrasonic motor is a type of electric motor formed
from the ultrasonic vibration.
• Conversion of electrical energy into motion by inverse
piezoelectric effect.
4. • To obtain the levels of torque speed characteristics of
USM using conventional motor we require to add a
gear system to reduce the speed.
• these characteristics USM makes them attractive for
robotics application where small motors are required.
Contd…
5. PIEZOELECTRICAL EFFECT
Piezoelectric effect is conversion of mechanical pressure
to electrical energy and conversion of electrical energy to
mechanical pressure is known as inverse piezoelectric
effect or Electrostriction.
Piezoelectricity : generation of voltage in response of
mechanical stress.
This effect is also reversible.
Piezoelectric materials are Quartz, Rochelle salt, Tourmaline,
Lead Zirconium Titanate etc.
7. Structure is divided into mainly four part:
o The Stator part transmits vibration.
o The Rotor which is a rotation part.
o The Shaft which transmits rotation.
o The Bearing.
Furthermore, the structure of a stator part
is the following:
o The Piezoelectric Ceramics which generate vibration.
o The Stator metal which makes vibration amplify.
o The Friction material which contacts with a rotor.
8. Working of ultrasonic motor
When electric voltage is applied on Piezoelectric
Ceramics plate , due to piezoelectric effect it vibrate
and as it is connect to stator , stator metal amplify the
vibration.
The Friction material which contacts with a rotor, is
connect rotor and stator to vibrate at same frequency.
Rotor start vibration and then at rotor metal surface
a potential is induced due to Electrostriction(inverse
piezoelectric effect) .
When at rotor voltage is induced a travelling wave is
generate which cause to create a torque which rotates
the rotor.
9. Advantages of Ultrasonic Motor over Electromechanical Motor
Electromechanical motors are famous for
consuming high amount of power and creating high
ambient motor temperatures respect to USM’s.
the electromagnetic motors produce strong magnetic
fields which cause interference. Ultrasonic motors use
piezoelectric effect and hence no magnetic interference.
Electromagnetic motor has high input to output
energy loss ratios while USM has low power loss.
USM high positional accuracy respect to
electromagnetic motor.
10. Contd…
USM is characterized as low speed and high torque
while EM motor is high speed and low toque.
The efficiency of electromagnetic motors falls as their
dimensions are reduced, but that of PUMs stay virtually
constant.
Linear electromagnetic motors are very difficult to
design while PUMs are quite simple.
USM has compact size and quite operation while EM
motor has bulky and noisy operation.
11. Contd…
Different velocities without gear-mechanisms.
USM’s are capable to work in extreme environment
working condition.
12. Disadvantages of Ultrasonic Motors
A high-frequency power supply is required.[in KHz
range]
As these motors operate on friction, durability is very
less.
Piezoelectric materials are expensive.
13. MAJOR APPLICATIONS
watch motors.
Used to inject oil into the burners.
Camera auto focus lenses.
Used to control the disk heads of computer like
floppies, hard disk and CD drives.
In automobiles industry.
Aerospace.
Medicine(in magnetic resonance imaging scanning)
Robotics.
Power steering and car seat adjustment.
surveillance cameras.
14. Conclusion
The above mentioned advantages and applications,
concludes the scope of ultrasonic motors in day-to-day
life.
However the disadvantages brings up the need of
further researches in the field of ultrasonic motors.
Hence the ultrasonic motors, which is a new step in
miniaturized electrical technology has got many
applications in small appliances because of its high
torque at low speed.
16. Additional Info
piezoelectric effect was discovered by Jacques
curie and pierre curie[France-1880].
first ultrasonic motor was developed by V. V.
Lavrinko[Russia-1965].
