Development of precision positioning control circuit of ultrasonic motor by pulse width high speed switching method

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K04337
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 21010:Power engineering-related
• Research Institution: Kindai University
• Principal Investigator: oka masato 近畿大学, 工学部, 教授 (70281582)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: Ultrasonic motor / Precise position control / Piezoelectric element / Actuator

Outline of Final Research Achievements

We developed a drive circuit that can change the frequency, voltage, and phase difference to any desired value. This drive circuit consists of a DDS and several high-voltage operational amplifiers to generate a sine wave. This circuit makes it possible to change the values of the three parameters that control the rotation speed of the ultrasonic motor at high speed and arbitrarily.
In conventional control methods, the rotational speed of the ultrasonic motor is varied by changing the frequency. However, there is a characteristic in which the control input value is not correctly reflected in the output value in the extremely slow rotation speed range. The proposed variable frequency and voltage control method enables the output value to be correctly reflected in relation to the control input value. Using these methods, high-precision positioning control was achieved.

Free Research Field

電子回路

Academic Significance and Societal Importance of the Research Achievements

超音波モータは非磁性体で構成でき、MRI(Magnetic resonance image)装置内で動作する手術支援ロボットのアクチュエータとしての応用が期待されている。MRI装置で撮影された画像を確認しながら手術することができれば、脳のような複雑な組織においても安全で正確な手術ができると考えられる。本研究では駆動回路および制御手法を見直すことにより、このモータをきわめて高精度に位置制御できることが確認できた。これによりMRI対応型の手術支援ロボットのアクチュエータとして用いることができる。