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ULTRASONIC MOTOR (USM)
GUIDED BYVISHNU PRATHAPASSISTANT PROFESSORMECHANICAL DEPT.Govt. Engg. College Idukki
PRESENTED BYARJUN SIBIROLL NO- 61. SEM-7MECHANICAL DEPT.Govt. Engg. College Idukki
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CONTENTS
INTRODUCTION TYPE OF USM WORKING PRINCIPLE STRUCTURE CONSTRUCTION WORKING ADVANTAGES DISADVANTAGES APPLICATIONS CONCLUSION REFERENCE
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INTRODUCTIONWhat is Motor? Motor is a device which convert electrical energy to mechanical energy
Almost all the motors work on the principle of Faraday’s Law of Electromagnetic Induction.
The energy conversion in such motors involves two stagesElectrical energy to magnetic energy
Magnetic to mechanical energy.
Because of two-stage electromagnetic motor suffer from several losses that lead to energy wastage
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A new class of motors using high power Ultrasonic motors were
introduced.
The ultrasonic motors also known as piezoelectric motors, which
directly convert electric energy to mechanical energy.
The first ultrasonic motor was introduce by V.V Lavrinko in 1965
INTRODUCTION OF USM 4
The Disadvantages Of Electromagnetic motors 5
Noisy operations
Magnetic losses
High power consumption
Low power factor
Comparatively lesser efficiency
TYPES OF ULTRASONIC MOTORULTRASONICMOTOR
STANDING WAVE TYPE
LINEARMOTOR
ROTARYMOTOR
TRAVELLINGWAVE TYPE
LINEARMOTOR
ROTARYMOTOR
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7LINEAR USM
Fig:-1
8ROTARY USM
Fig:-2
WORKING PRINCIPLE
PIEZOELECTRIC EFFECT
In certain types of crystals when a pressure is applied across a pair of opposite faces, an equivalent potential difference is developed across the other pair of opposite faces.
Converse of this phenomenon is also possible.
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Fig:-3
PIEZOELECTRIC MATERIAL USED
Quartz(SiO2).
Barium titanate (BaTiO3).
Lead zirconate titanate(PbZrTiO3).
Lithium niobate titanate(LiNbO3).
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Compressing Force Potential difference`11
Fig:-4
BASIC STRUCTURE12
Fig:-5
C O N S T R U C T I O N
The Ultrasonic Motors constitutes mainly four parts
Actuator
Stator
Rotor
Casing
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Fig:-6
ACTUATOR
It is the driving unit.
Made up of piezoelectric material (Quartz, Barium Titanate, Tourmaline, Rochelle salt, etc).
Fixed on the stator using thin metal sheets and bearings.
Directly connected to the supply mains.
`
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STATOR
Stator is the stationary but vibrating part.
It is constructed using a malleable material, usually steel.
It can be of ring, cylindrical or rod shaped.`
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ROTOR
It is the rotating part, which acquires the energy conversion
Produces the desired torque on the shaft.
It is made of the same material as that of the stator and does have the
same shape.
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CASING
To provide protection against abrasive forces, external interferences
and extreme environmental conditions.
They are made of non- corrosive alloys or fiber.
Cylindrical, disc or box shaped.
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FUNDAMENTAL CONSTRUCTION OF USM 18
Fig:-7
Consist of a high-frequency power supply.Connected to Vibrator. Vibrator is composed of a piezoelectric driving component and an
elastic vibratory part.
The slider is composed of an elastic moving part and a friction coat.
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WORKING OF USM
When the supply is switched ON, the actuator starts vibrating owing to
converse piezoelectric effect.
The particles of the stator receive energy from the actuator and starts
vibrating in the plane.Results in the formation of a surface wave.
The stator and rotor are placed so close to each other that their surfaces
almost grazes upon each other.
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The surface waves so produced ultrasonic frequency range. Not visible by our bare eyes.
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Fig:-8
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Fig:-9
Wave propagates the rotor is pulled back in the opposite direction of movement of the wave
Surface wave is propagating in the anti-clockwise direction Rotor is pulled to rotate in the clockwise direction.
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Fig:-10
The shaft is mounted upon the rotor. Rotor rotates and the output torque is obtain.
The stator and rotor always possess the same shape.`
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Fig:11
The other methods of classifications of USM
Type of motion* Rotary
* Linear * Spherical
Shape of implementation * Beam * Rod * Disk
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ADVANTAGES 26
High output torque & efficiency
Good positioning accuracy
Capable of working in extreme environmental conditions.
Simple construction
Compact size.
Energy saving
27DISADVANTAGE
High frequency supply range
Cost of Piezoelectric crystal
Large field application is not possible now.
28APPLICATIONS
Auto focusing & optical zooming in digital cameras
Surveillance cameras.
The disk heads of hard disks
CD drives Controlling
Wrist watches & Clocks
Robotics
Aerospace
Medicine
29Auto focusing& optical zooming
Fig:-12 Fig:-13
30Disk heads of hard disks
Fig:-14
Fig:-15
31CASE STUDY
The case study is done in MRI robor bv ts by using PIEZO LEGS motors
ORAGNIZATIONWorcester Polytechnic Institute USA
INDUSTRYMedical Robotic Surgical Tools USA
Fig:-16
32 Surgical robot designed for use inside an MRI machine that can
operate within the high magnetic fields generated by an MRI.
Any electrical noise generated by power supply or drive electronics
is to distort the image
Here the MRI robot required up to about 100 mm of linear travel or
a continuous 360 degree rotation
CHALLENGES
33USM SPECIFICATION
Piezo LEGS Linear 10
It delivers micro-steps as long as 4 μm with nano-scale resolution.
which moves a 100.8-mm drive rod over of 80 mm at speeds as high as 10 mm/s.
Fig:-17
34Piezo LEGS Rotary 50
which provides positioning over 360° at micro-radian resolutions.
Fig:-18
35CASESTUDY RESULTS
They can capture ultra-high-resolution images of the tumor
using magnetic resonance imaging.
They can use ultra-precise surgical tools to remove the tumor.
Can operate within the high magnetic fields generated by an
MRI unit.
36BEFORE USING USM AFTER USING USM
CONCLUSIONS
The USM which is a new step in the miniaturized electrical technology
Many applications in small appliances because of its high torque at low density.
USMs are not widely used for heavy motoring activities.
World might be expected in the near future that replaces the futile electromagnetic motors by the proficient ultrasonic motors.
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38REFERENCES[1] Shi Jingzhuo,You Dongmei.“Characteristic model of travelling wave ultrasonic motor”. School of Electrical Engineering, Henan University of Science and Technology, Luoyang 471023, China. 0041-621X-(2013) [2] Yingxiang Liu, Weishan Chen, Junkao Liu, Shengjun Shi.“A cylindrical standing wave ultrasonic motor using bending vibration transducer”. State Key Laboratory of Robotics and System, Harbin Institute of Technology, Harbin 150001, Heilongjiang Province, China, 0041-62MX2010) Elsevier B.V. [3] Xiang Li , Zhiyuan Yao, Shengli Zhou, Qibao Lv, Zhen Liu.“Dynamic modeling and characteristics analysis of a modal-independent linear ultrasonic motor”.State Key Laboratory of Mechanics and Control of Mechanical Structures, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China0041-624YAX/( 2016) Elsevier B.V.
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