FEM Optimization Project


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Course project involving use of FEM software ATILA for optimization of ultrasonic motor

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FEM Optimization Project

  1. 1. METAL TUBE ULTRASONIC MOTOR FEM Applications – EE 597B By Siddharth Advani
  2. 2. Outline <ul><li>Introduction </li></ul><ul><li>Significance </li></ul><ul><li>Simulation Process </li></ul><ul><li>Design Specifications </li></ul><ul><li>Optimization Procedure </li></ul><ul><li>Applications </li></ul><ul><li>Conclusion </li></ul>
  3. 3. Introduction <ul><li>The motor is driven by ultrasonic vibration force </li></ul><ul><li>Its stator is composed of an elastic material and PZT plates poled in thickness direction </li></ul>
  4. 4. Significance of USM <ul><li>High displacement control </li></ul><ul><li>Absence of magnetic fields </li></ul><ul><li>High thrust to weight ratio </li></ul><ul><li>Frictional locking at the power off stage </li></ul>Makes USM motors good candidates for micromechatronic applications
  5. 5. Comparisons
  6. 6. Simulation Process <ul><li>A miniaturized metal tube ultrasonic motor is simulated </li></ul><ul><li>Two flattened surfaces are ground at different angles on the outer surface of the stator </li></ul><ul><li>Two PZT-based piezoelectric ceramics are bonded onto these surfaces </li></ul><ul><li>The asymmetrical surface of the stator developed the split of the two degenerated orthogonal bending modes, resulting in a wobble motion </li></ul><ul><li>The angle between the two PZT plates is the parameter to be changed in order to seek maximum wobbling displacement </li></ul>
  7. 7. Simulation Process <ul><li>The optimum orientation angle of the PZT ceramic will differ based upon: </li></ul><ul><li>Type of the elastic material </li></ul><ul><li>Geometry of the elastic material </li></ul><ul><li>Cross-section shape </li></ul><ul><li>Optimization steps </li></ul><ul><li>5 degree angle optimization </li></ul><ul><li>2 degree angle optimization </li></ul><ul><li>Maximum vibration amplitude </li></ul>Copper Tube Circular
  8. 8. Structure and Assembly
  9. 9. Design Specifications <ul><li>Materials & Dimensions </li></ul><ul><li>Tube : Copper: </li></ul><ul><li>Outer Diameter – 2.4 mm Φ, </li></ul><ul><li>Inner Diameter – 1.8 mm Φ </li></ul><ul><li>Length = 5 mm </li></ul><ul><li>Plate : PZT 4: 0.3 mm t x 1 mm x 5 mm </li></ul><ul><li>Driving conditions </li></ul><ul><li>1V potential applied to both plates </li></ul>Grounded Down to up Y Sine 1 V Right to left X Voltage Polarization Plate
  10. 10. Mesh Snapshot 3600 nodes
  11. 11. 5 degree angle optimization 95 degrees 90 degrees 85 degrees The key is to adjust the two split resonance peaks corresponding to two orthogonal bending modes. When the two peaks almost overlap, maximum wobbling vibration amplitude is obtained. Position Optimization of the Piezoelectric Plates on the Surface of the Metal Tube
  12. 12. Admittance Spectrums 85 degrees 90 degrees 95 degrees 227 kHz 205 kHz 227 kHz 229 kHz 226 kHz 229 kHz Optimization range is between 85 degrees and 90 degrees.
  13. 13. 2 degree angle optimization The key is to adjust the two split resonance peaks corresponding to two orthogonal bending modes. When the two peaks almost overlap, maximum wobbling vibration amplitude is obtained. 87 degrees 227 kHz 89 degrees 227 kHz 229 kHz
  14. 14. Optimization Graph
  15. 15. First Bending Mode Angle = 89 degrees Frequency = 227 kHz
  16. 16. First Bending Mode Angle = 89 degrees Frequency = 229 kHz
  17. 17. Hula-Hoop Mode Angle = 89 degrees Frequency = 228 kHz
  18. 18. Applications <ul><li>Zoom/focus mechanism of cellular phone camera </li></ul><ul><li>Can also be applied to a compact surveillance camera on unmanned aerial or underwater vehicles. </li></ul>
  19. 19. Conclusions <ul><li>Optimum angle for metal tube motor having copper tube is 89 degrees </li></ul><ul><li>The excitation of plate X provides a clockwise direction, and that of plate Y reveales a counterclockwise direction. </li></ul><ul><li>Because the structure and poling configuration of the </li></ul><ul><li>active piezoelectric elements used in the stator are simple, this motor structure is very suitable for miniaturization </li></ul>
  20. 20. References <ul><li>Serra Cagatay, Burhanettin Koc and Kenji Uchino, A 1.6-mm, Metal Tube Ultrasonic Motor , IEEE Transactions on Ultrasoniccs, Ferroelectrics and Frequency Control, Volume 50, No 7,  July 2003 Page(s):782 - 786 </li></ul><ul><li>Kenji Uchino, FEM and Micromechatronics with ATILA software , CRC Press, 2008 </li></ul><ul><li>Kenji Uchino and JayneGiniewicz, Micromechatronics, Marcel Dekker 2003 </li></ul><ul><li>www.micromechatronicsinc.com </li></ul><ul><li>Yoseph Bar-Cohen, Mike Lih and Nesbitt W. Hagood, Miniature Ultrasonic Rotary Motors, 2nd Micromachining Workshop, Anaheim, CA, September 27 and 28, 1995 </li></ul>
  21. 21. Thank-you!