TY - GEN

T1 - Torque characteristics analysis of a traveling wave type ultrasonic motor impressed high load torque in low speed range

AU - Ogahara, Yoichi

AU - Maeno, Takashi

PY - 2004/12/1

Y1 - 2004/12/1

N2 - 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.

AB - 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.

KW - Equivalent circuit

KW - Torque control

KW - Traveling wave type

KW - Ultrasonic motor

KW - Vibration amplitude

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U2 - 10.1109/ULTSYM.2004.1418293

DO - 10.1109/ULTSYM.2004.1418293

M3 - Conference contribution

AN - SCOPUS:21644446317

SN - 0780384121

T3 - Proceedings - IEEE Ultrasonics Symposium

SP - 2271

EP - 2274

BT - Proceedings - 2004 IEEE Ultrasonics Symposium

A2 - Yuhas, M.P.

T2 - 2004 IEEE Ultrasonics Symposium

Y2 - 23 August 2004 through 27 August 2004

ER -