ULTRASONIC MOTOR

ULTRASONIC MOTOR ( BY AVINASH MEENA 9703174752)

1. ULTRASONIC MOTOR (USM) PRESENTED BY AVINASH MEENA ROLL NO- 132107 B.TECH- 4/4 ELECTRICAL AND ELECTRONICS ENGINEERING NIT WARANGAL 1

2. CONTENTS INTRODUCTION WORKING PRINCIPLE STRUCTURE CONSTRUCTION WORKING TYPE OF USM CHARACTERISTICS ADVANTAGES DISADVANTAGES APPLICATIONS CONCLUSION REFERENCE 2

3. INTRODUCTION What 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 stages Electrical energy to magnetic energy Magnetic to mechanical energy. Because of two-stage electromagnetic motor suffer from several losses that lead to energy wastage 3

4. 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 L avrinko in 1965 INTRODUCTION OF USM 4

5. 5 It has very good torque-speed characteristics. These characteristics of USM makes them attractive for robotic applications where small motions are required. Conversion of electric energy into motion by piezoelectric effect. USMs replaced not only the EM motors, but also the servomotors, stepper motors and synchronous motors. 5

6. The Disadvantages Of E lectromagnetic motors 6 Noisy operations Magnetic losses High power consumption Low power factor Comparatively lesser efficiency

7. WORKING PRINCIPLE PIEZOELECTRIC EFFECT Before learning about USMs it is required to know about piezoelectric effect. In figure given below, a compressive force is applied across the crystal and we obtain a potential difference as shown but if the compressive force is replaced by an elongation force, the polarity reverses. 7

8. 8 Converse of this phenomenon is also possible. When a potential difference is applied across the pair of opposite faces, compressions or elongations are obtained across the other pair of opposite faces depending upon the polarity of the applied PD. Further, the application of AC voltage across these faces resulted in alternating compressions and elongations (mechanical vibrations) across the other pair of faces. This is the driving force behind the USMs. Crystals that exhibit the above phenomenon are called piezoelectric materials. In short, the Ultrasonic Motors works on the principle of converse piezoelectric effect. 8

9. PIEZOELECTRIC MATERIAL USED Quartz(SiO 2 ). Barium titanate ( BaTiO 3 ). Lead zirconate titanate( PbZrTiO 3 ). Lithium niobate titanate (LiNbO 3 ). 9

10. BASIC STRUCTURE 10

11. CONSTRUCTION The Ultrasonic Motors constitutes mainly four parts Actuator Stator Rotor Casing 11

12. ACTUATOR It is the driving unit. M ade up of piezoelectric material (Quartz , Barium Titanate, Tourmaline, Rochelle salt , etc). F ixed on the stator using thin metal sheets and bearings. Directly connected to the supply mains . ` 12

13. 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 .` 13

14. 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. 14

15. 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. 15

16. FUNDAMENTAL CONSTRUCTION OF USM 16 Fig :-7

17. 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. 17

18. 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. 18

19. The surface waves so produced ultrasonic frequency range. N ot visible by our bare eyes. 19

20. 20

21. 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. 21

22. The shaft is mounted upon the rotor. Rotor rotates and the output torque is obtain. The stator and rotor always possess the same shape.` 22

23. 23 ULTRASONIC MOTOR STANDING WAVE TYPE LINEAR MOTOR ROTARY MOTOR TRAVELLING WAVE TYPE LINEAR MOTOR ROTARY MOTOR TYPES OF ULTRASONIC MOTOR 23

24. 24 STANDING WAVE TYPE USM The first ultrasonic standing wave motor was proposed by H.V. Barth in 1973. The standing-wave type is sometimes referred to as a vibratory-coupler type or a woodpecker type. A vibratory piece is connected to a piezoelectric driver and the tip portion generates flat elliptical movement. the vibratory piece generates bending because of restriction by the rotor, 24

25. 25 1. LINEAR TYPE STANDING WAVE USM K Uchino et al invented a π-shaped linear motor. This linear motor is equipped with a multilayer piezoelectric actuator and fork-shaped metallic legs. Since there is a slight difference in the mechanical resonance frequency between the two legs, the phase difference between the bending vibrations of both legs can be controlled by changing the drive frequency. 25

26. 26 ROTATING TYPE STANDING WAVE USM The torsion coupler consisting of two legs which transform longitudinal vibration. Extruder is aligned with a certain cant angle to the legs, which transforms the bending to a torsion vibration. This transverse moment coupled with the bending up–down motion leads to an elliptical rotation on the tip portion. 26

27. 27 The standing-wave type is Low in cost (one vibration source) and High efficiency (up to 98% theoretically) But lack of control in both clockwise and counterclockwise directions. 27

28. 28 TRAVELLING WAVE USM The propagating-wave type combines two standing waves with a 90 degree phase difference both in time and in space. A surface particle of the elastic body draws an elliptical locus due to the coupling of longitudinal and transverse waves. 28

29. 29 LINEAR TYPE TRAVELLING WAVE USM Linear motor using bending vibration. The two piezoelectric vibrators installed at both ends of a transmittance steel rod excite and receive the traveling transverse wave. Adjusting a load resistance in the receiving vibrator leads to a perfect traveling wave. Exchanging the role of exciting and receiving piezo-components provided a reverse moving direction. 29

30. 30 ROTARY TYPE TRAVELLING USM T wo voltage sources are used to produce travelling wave. Vibrations of the piezoelectric material is amplified by the stator teeth. Due to frictional forces rotor rotates. 30 30

31. 31 THE TRAVELLING-WAVE TYPE- Requires two vibrating source. Controllable in both direction. Silent operation, so suitable to video cameras with microphone. Thinner design, leading to space saving. Low efficiency(not more than 50%) Energy saving. 31

32. The other methods of classifications of USM Type of motion 1. Rotary 2.Linear 3.Spherical Shape of implementation 1. Beam 2. Rod 3.Disk 32

33. 33 LINEAR USM 33

34. 34 ROTARY USM 34

35. 35 CHARACTERISTICS 35

36. 36 36

37. ADVANTAGES 37 High output torque & efficiency Good positioning accuracy Capable of working in extreme environmental conditions. Simple construction Compact size. Energy saving

38. 38 DISADVANTAGE High frequency supply range Cost of Piezoelectric crystal Large field application is not possible now.

39. 39 APPLICATIONS Auto focusing & optical zooming in digital cameras Surveillance cameras. The disk heads of hard disks CD drives Controlling Wrist watches & Clocks Robotics Aerospace

40. 40 Auto focusing& optical zooming

41. 41 Disk heads of hard disks Fig:- 14 Fig:- 15

42. 42 Surveillance cameras 42

43. Wrist watches & Clocks 43

44. 44 Robotics 44

45. 45 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. W orld might be expected in the near future that replaces the futile electromagnetic motors by the proficient ultrasonic motors. 45

46. 46 REFERENCES [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, China 0041-624YAX /( 2016) Elsevier B.V.

47. 47 QUESTIONS ? 47

48. 48