Torque characteristics analysis of a traveling wave type ultrasonic motor impressed high load torque in low speed range

Yoichi Ogahara, Takashi Maeno

Research output: Chapter in Book/Report/Conference proceedingConference contribution

9 Citations (Scopus)


As an alternative to an electromagnetic motor, a rotary traveling wave type ultrasonic motor (USM) has been attracted considerable attention. The rotary traveling wave type is more commonly used in industrial applications. In this paper, the USM impressed high load torque in low speed range is modeled using an equivalent circuit and a new torque control method is proposed to implement for a robot manipulator. Firstly, the USM is modeled using the equivalent circuit based on a piezoelectric equation and a mechanical model. In mechanical approach, the ratio of vibration speed of the vibrator to rotational speed of the rotor is assumed as 1: n, where n is a smaller variable than 1. According to this proposed equivalent circuit, if vibration amplitude of the vibrator is constant, output torque is proportional to voltage magnitude applied to piezoelectric ceramics and rotational speed of the rotor. Secondly, three parameters of two sinusoidal voltages: frequency, magnitude and phase difference are determined to control output torque. Finally, an experiment is conducted to verify the equivalent circuit model. Experimental results show that output torque of the USM is proportional to applied voltage magnitude. Therefore, the proposed model is shown to be valid and will be applied to robot manipulators.

Original languageEnglish
Title of host publicationProceedings - 2004 IEEE Ultrasonics Symposium
Subtitle of host publicationA Conference of the IEEE International Ultrasonics, Ferroelectrics, and Frequency Control Society, UFFC-S
EditorsM.P. Yuhas
Number of pages4
Publication statusPublished - 2004 Dec 1
Event2004 IEEE Ultrasonics Symposium - Montreal, Que., Canada
Duration: 2004 Aug 232004 Aug 27

Publication series

NameProceedings - IEEE Ultrasonics Symposium
ISSN (Print)1051-0117


Other2004 IEEE Ultrasonics Symposium
CityMontreal, Que.


  • Equivalent circuit
  • Torque control
  • Traveling wave type
  • Ultrasonic motor
  • Vibration amplitude

ASJC Scopus subject areas

  • Acoustics and Ultrasonics


Dive into the research topics of 'Torque characteristics analysis of a traveling wave type ultrasonic motor impressed high load torque in low speed range'. Together they form a unique fingerprint.

Cite this