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077.pptx
1. 1
Department of Electrical and Electronics Engineering
15-08-2022
ULTRASONIC
MOTOR
Name: VIJAY S HIREMATH
USN : 4NM19EE077
2. 2
Department of Electrical and Electronics Engineering
15-08-2022
Content
• Introduction
• Piezoelectric Effect
• Advantages of USM
• Basic Principle
• Fundamental Construction
• Types of USM
• Working Mechanism
• Application
• Conclusion
3. 3
Department of Electrical and Electronics Engineering
15-08-2022
Introduction
• It has been known for more than 30 years
• The first ultrasonic motor was introduce by v.v lavrinko in 1965
• An Ultrasonic motor is a type of electric motor formed from the ultrasonic vibration of a
component, the stator being placed against another, the rotor depending on the scheme of
operation
• Conversion of electric energy into motion by inverse piezoelectric effect
• To obtain the levels of torque speed characteristics of USM using conventional motors we
require to add a gear system to reduce the speed
• 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
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Department of Electrical and Electronics Engineering
15-08-2022
What is Piezoelectric effect?
The piezoelectric effect is understood as the linear electromechanical interaction between the
mechanical and the electrical state in crystalline materials with no inversion symmetry
• Piezoelectricity – generation of voltage in response of 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) lead zirconate titanate and
occasionally lithium niobate
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Department of Electrical and Electronics Engineering
15-08-2022
Advantages
• Electromagnetic motors are notorious 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
• Electromagnetic motor has high input to output energy loss ratios
• USM High positional accuracy respect to Electromagnetic Motor
vs
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Department of Electrical and Electronics Engineering
15-08-2022
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
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Department of Electrical and Electronics Engineering
15-08-2022
Types of USM
Ultrasonic
Motors
Standing Wave
Bidirectional
Unidirectional
Traveling
Wave
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Department of Electrical and Electronics Engineering
15-08-2022
Standing Wave USM
• 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
• This type of motor commonly known under the
names of Inchworm, Piezo LEGS or PiezoWalk
motors
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Department of Electrical and Electronics Engineering
15-08-2022
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
• 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 micro-motion 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
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Department of Electrical and Electronics Engineering
15-08-2022
Applications
• Camera auto focus lenses
• Driving fluid
• Watch motors and compact paper handling
• Optoelectronics area
• In micro surgery and sensor scanning
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Department of Electrical and Electronics Engineering
15-08-2022
Conclusion
Hence the ultrasonic motors, which is a new step in the miniaturized
electrical technology has got many applications in small appliances because
of its high torque at low density
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Department of Electrical and Electronics Engineering
15-08-2022
Reference
• M. Kuribayashi, S. Ueha and E. Mori, "Excitation conditions of flexural traveling
waves for a reversible ultrasonic linear motor", J. Acoust. Soc. Am., vol. 77, no. 4, pp.
1431-1435, Apr. 1985
• T. Sashida, "Trial construction of an ultrasonic vibration driven motor", Oyo
Butsuri, vol. 51, no. 6, pp. 713-720, 1982
• S. Takahashi, "Multilayer piezoelectric ceramic actuators and their
applications", Jpn. J. Appl. Phys., vol. 24, no. Suppl.24-2, pp. 41-45, 1985