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.

Ultrasonic motor

Standing wave

Traveling wave

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