Ultra sonic motor
-
Upload
fenil-patel -
Category
Engineering
-
view
625 -
download
3
Transcript of Ultra sonic motor
SEMINAR
ON
“ULTRASONIC MOTOR”
Prepared by,
Fenil S Patel
M.E.ELECTRICAL
[130030745015]
Guided by,
Prof. Shilpa Kaila
Dept. of Elec. Engg.
AITS-Rajkot
It has been known from more than 30 years.
After some research work now a days it is implementedin our small applications.
An Ultrasonic motor is a type of electric motor formedfrom the ultrasonic vibration of a component, and thatvibration is feel by the stator, the rotor depending on thescheme of operation.
Conversion of electric energy into motion bypiezoelectric effect.
It has very good torque-speed characteristics.
These characteristics of USM makes them attractive
for robotic applications where small motions are
required.
This motor achieves high speed and drive forces,
while still permitting the moving part to be positioned
with high accuracy.
Piezoelectricity – generation of voltage in response of
mechanical stress.
Deformation is only 0.1 % of the original dimension.
Piezoelectric material:- quartz(SiO2), barium titanate (BaTiO3)
Rochelle salt and certain types of ceramics.
“The piezoelectric effect is understood as the linear
electromechanical interaction between the mechanical
and the electrical state in crystalline materials with no
inversion symmetry.”
Electromagnetic motors are famous for consuming high amount
of power and creating high ambient motor temperatures respect
to USM
The electromagnetic motors produce strong magnetic fields
which cause interference. Ultrasonic motors use piezoelectric
effect and hence no magnetic interference.
Piezoelectric motor has High positional accuracy respect to
Electromagnetic Motor.
When a voltage is applied to a piezoelectric element,
alternating expansion and contraction occur either in
the ceramic body itself or in the piezoelectric body
And that body is connected with stator.
So the stator is also vibrate.
Frictional interface between the rotor and stator.
This produce the motion in the ROTOR.
And its Working frequency is around 20 KHz to 10
MHz.
This type of motors use three groups of crystals: two of
which are Locking and one Motive.
First, one group of locking crystals is activated this
gives one locked side and one unlocked side of the
'sandwich'.
Next, the motive crystal group is triggered and held
the expansion of this group moves the unlocked
locking group along the motor path. This is the only
stage where motor movement takes place.
In this stator is particles vibrating only in vertical
direction.
Low cost, and unidirectional,
The active material excites a traveling wave withinthe stator that leads to elliptical motion of the surfaceparticles.
The stator has its particles vibrating both in thevertical direction as well as horizontal direction.
The rectification of the micro-motion an interface isprovided by pressing the rotor on top of the statorand the frictional force between the two causes therotor to spin.
Controllable in both direction.
Low cost
High efficiency
No magnetic interference
Compact size
High torque/weight ratio
Energy saving
Use of high frequency power supply
Piezoelectric material is expensive.
Ultrasonic noise occurs.
Due to friction life of motor is become less.
Auto focusing & optical zooming
in digital cameras.
Wrist watches & Clocks.
Robotics.
Aerospace.
Medical application.
Hardware positioning (Hard
disks, Floppy & CD Drives) etc.
The above mentioned advantages and applications,
concludes the scope of USMs in the day-to-day life.
Hence the ultrasonic motors, which is a new step in
the electrical technology has got many small
applications because of its high torque at low
density.
However the disadvantages brings up the need
for further researches in the field.
Suppose if we can minimize the friction loss
between stator and rotor by implementing some
new techniques then this motor is become more
useful than conventional motor.
1) http://en.wikipedia.org/wiki/Ultrasonic_motor
2) www. google. com
3) Weishan Chen, Yingxiang Liu, “Ring-Type
Traveling Wave Ultrasonic Motor” IEEE
Transactions on Ultrasonics, Ferroelectrics, and
Frequency Control, vol. 61, no. 1, January 2014
4) www . slideshow.com