Loading...

Modeling, Study of Operational Characteristics and Fabrication of an Ultrasonic Linear Motor

Sanikhani, Hamed | 2021

412 Viewed
  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 53937 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Akbari, Javad
  7. Abstract:
  8. Nowadays, piezoelectric motors are used as one of the suitable options in the modern motion control field and precise positioning systems due to their suitable functional characteristics such as high power to weight ratio, fast dynamic response, direct drive motion, integrated structure without backlash and possibility of miniature design. Accordingly, the present dissertation is defined in order to develop a comprehensive path for modeling, analysis and optimization of the ultrasonic piezoelectric motors. In this study, the focus is on the ultrasonic motors with an elliptical structure, but the results can be used for other structures as well. In the present work, the process of modeling of the motor is first discussed in which the motor is divided into two modules, stator and rotor, which interact with each other at the stator tip point. The implemented modeling method includes the finite element method for the stator analysis and an analytical method to derive the equations of stator and rotor interaction as well as the rotor equation of motion. Finally, after coupling of these two modules, modeling process is completed. This modeling process is generally more comprehensive and accurate than analytical methods- which is often accompanied by simplification - and is also much faster and have lower computational costs respect to the complete finite element modeling method. After describing the modeling method on a prototype motor, identification and performance tests are performed and the modeling method is validated. This prototype with weight of 2.1 N, has no-load speed of 40 mm/s and maximum force of 1.5 N at excitation voltage of 140 Vpp and 18500 Hz. In the next step, the extracted modeling and optimization process is used to design a miniature motor that is more applicable in modern control systems. By applying some proper changes to the details design of the final model as well as defining a more applicable objective function (F.V/w) in the genetic algorithm optimization method, are tried to improve operational characteristics of the motor. In the final prototype, the error in the natural frequency values is reduced from about 10% to less than 3% compared to the first prototype. Also, the value of the objective function is increased from 0.03 to 0.91. The final prototype has a speed of 127 mm/\s and a maximum force of 1 N, while its weight is about 0.14 N, at a voltage of 10 Vpp and a frequency of 22450 Hz. An important part of this improvement in the output characteristics is resulting from the use of the described modeling method as well as the optimization used in the research. Finally, in order to complete the research, a design of a miniature hybrid motor with the capability of two fast and accurate working modes is presented and its operating principles is studied. Then the design and optimization process are done on this sample. The final design of this motor based on numerical simulations has a weight of 0.05 N and at a voltage of 20 Vpp and a frequency of 26.08 kHz has a speed of 1900 mm/s and a force of 0.28N. In summarizing of this research, the operational specifications of the manufactured and designed prototypes are compared with the results of the similar researches, which shows that with using of this modeling process with working on the details of the design, motors with the appropriate objective function values can be obtained (compared to the average of the similar researches). In addition, motors with a desired performance can be provided by using different objective functions on the output characteristics
  9. Keywords:
  10. Piezoelectric Actuator ; Forced Vibration ; Positioning ; Vibrational Modes ; Ultrasonic Motor ; Linear Ultrasonic Motor

 Digital Object List

 Bookmark

No TOC