Design and Experiments of Flexible Ultrasonic Motor Using a Coil Spring Slider

Ayato Kanada, Tomoaki Mashimo

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)


This article proposes a flexible ultrasonic motor that consists of a single metal cube stator with a hole and an elastic elongated coil spring inserted into the hole. When voltages are applied to piezoelectric plates on the stator, the coil spring moves back and forward as a linear slider. The use of the coil spring brings flexibility for the motor and enables a long stroke to access to deeper sites. Furthermore, the coil spring provides an appropriate prepressure between the stator and the coil spring to enhance the motor output. We formulate the relation between the coil spring parameters and the prepressure to clarify the design methodology of the flexible ultrasonic motor. We model the linear motion of the coil spring by an equation of motion and compare it with the transient response by experiments. The flexible ultrasonic motor prototype achieved a translation at a speed of 120 mm/s and demonstrated a force of 0.45 N, and a stable motion even when the coil spring is being bent.

Original languageEnglish
Article number8932620
Pages (from-to)468-476
Number of pages9
JournalIEEE/ASME Transactions on Mechatronics
Issue number1
Publication statusPublished - Feb 2020
Externally publishedYes


  • Coil spring
  • continuum robot
  • prepressure
  • soft actuator
  • ultrasonic motor

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Computer Science Applications
  • Electrical and Electronic Engineering


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