Özet:

The purpose of this study is to develop a miniature motor for directional adjustment of a vascular endoscopic camera. Spherical ultrasonic motor not affected by magnetic fields is used in the miniature motor. The characteristic of spherical ultrasonic motor is that one motor has multi degree of freedom in rotational direction. Wire is used as stator to realize miniaturization of the motor, so it is called miniature spherical ultrasonic motor using wire stators. Firstly, the pressing force between a stator and a spherical rotor is discussed, which is important for developing a miniature spherical ultrasonic motor using wire stators. As a result, it can be clarified that there is an optimum value for the pressing force. Secondly, the starting torque is investigated, which is one characteristic of the miniature spherical ultrasonic motor using wire stators. The relationship between the frequency and amplitude of the applied AC voltage and the starting torque is clarified. Finally, the control method of the rotational direction of a miniature spherical ultrasonic motor using wire stators is discussed. A PWM control method is proposed to control the rotational direction of an ultrasonic motor. In this PWM control, traveling wave and standing wave generated on a wire stator are used. Experimental results show that the proposed method is effective.

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