Seminar on ULTRASONIC MOTORS By Madhu Patel K G (1SG07EE021)

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Seminar onULTRASONIC MOTORSByMadhu Patel K G
(1SG07EE021)

• Department of Electrical and Electronics
  Engineering,
• SAPTHAGIRI COLLEGE OF ENGINEERING
• Bangalore- 560 057

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Contents

• Introduction
• Working of USM
• Principle of operation
• Mechanism
• Types of USM
• Applications
• Conclusion

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INTRODUCTION

• 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.
• These motors offer high torque density at low
  speed, high holding torque, simple construction
  and have a quick response.

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• To obtain the levels of torque speed
  characteristics of USM using conventional motors
  we require to add a gear system to reduce the
  speed.
• USMs are fundamentally designed to have high
  holding force,providing zero backlash.
• These characteristics of USM makes them
  attractive for robotic applications where small
  motions are required.

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ULTRASONIC MOTOR
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WORKING OF USM

• A traveling wave is established over the stator
  surface, which behaves as an elastic ring and
  produces elliptical motion at the inter face with
  the rotor.
• This elliptical motion of the contact surface
  propels the rotor and the drive shaft connected
  to it.
• The teeth which are attached to the stator are
  intended to increase the moment arm to amplify
  the speed.

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TRAVELLING WAVE IN USM
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Principle of operation

• The general principle of operation of the
  ultrasonic motors is to generate gross mechanical
  motion through the amplification and repetition
  of micro deformations of the active material.
• The active material, induces an orbital motion of
  the stator at the rotor contact points to produce
  macro motion of the stator.

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• The active material which is a piezoelectric
  material excites a traveling flexural wave within
  the stator that leads to the elliptical motion of
  the stator.
• Teeth are used to enhance the speed that is
  associated with the propelling effect of these
  particles.
• The frictional force between the stator and rotor
  causes the rotor to spin.

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Mechanism

• Dry friction is often used in contact and the the
  ultra sonic vibration induced in the stator is
  used both to impart motion to the rotor and to
  modulate the frictional force present at the
  interface.
• An exceptionally high torque hybrid transducer
  ultrasonic motor uses circumferentially poled and
  axially poled piezoelectric elements to combine
  axial and torsional vibration.

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TYPES OF USM

• Bi-directional linear standing wave USM
• Rotary Ultrasonic Motor
• Spherical ultrasonic motor

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Applications

• Canon was one of the pioneers of the ultrasonic
  motors and made it famous for the manufacture of
  the auto focus lenses.
• USMs are also used in watch motors and compact
  paper handling, in spacecraft instruments and
  subsystems.

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ULTRASONIC MOTORS IN ROBOTICS
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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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• QUERIES?

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? THANK U ?