• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 D
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• pp.1720-1722
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• 1999

In this paper, we studied the properties of small-size disk-type ultrasonic motor using travelling wave for the application to the precise control robotic joint motor and fabricated it. The diameter of the ultrasonic motor fabricated was 13mm. Also, the piezoelectric vibrator was constructed by piezoelectric ceramic and elastic material. The piezoelectric ceramic was composed to PZ-PT-PMN which was shown the high electromechanical stability under high vibration level and stainless steel was used as the elastic material in which configuration was disk-type. To conform the capability of application to robotic motor, we measured the change of rotational speed according to applied voltage and applied frequency. As the results, the small-size disk-type ultrasonic motor was able to fabricate, and the revolution speed was 350 [rpm] when input voltage was 55 [Vrms] and applied frequency 160.4 [kHz] under pre-load.

• 동력기계공학회지
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• 제17권4호
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• pp.139-146
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• 2013

Because the magnetic bearing supports levitating body without contact, wear, noise and vibration, it is very useful to high revolution machinery. In this paper we selected ATmega 128, a less expensive and widely used micro controller, for control the magnetic bearing system. And we selected the sampling time and the control gain of PID controller through trial-and-error. The control program of the one board controller utilized lookup table to reduce calculation time, and bit shifting for the integer calculation in instead of floating point calculation. As the results, the controller carried out relatively high speed PID control on sampling time 0.25 ms. At last the rotation test for the magnetic bearing system was carried out by 3 phase induction motor and air turbine.

• 센서학회지
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• 제24권4호
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• pp.228-231
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• 2015

Ultrasonic motors provide high torques and quick responses compared to their magnetic counterparts; therefore, they are widely used in small-scale applications such as mobile phones, microrobots, and auto-focusing modules in digital cameras. To determine the feasibility of lead-free piezoceramics for ultrasonic motor applications, we fabricated a ring-type piezoceramic with a KNN-based lead-free piezoceramic (referred to as CZ5), intended for use in an auto-focusing module of a digital camera. The vibration of the lead-free stator was observed at 45.1 kHz. It is noteworthy that the fully assembled lead-free ultrasonic motor exhibited a revolution speed of 5-7 rpm, even though impedance matching with neighboring components was not considered. This result suggests that the tested KNN-based piezoceramic has great potential for use in ultrasonic motor applications, requiring minimal modifications to existing lead-based systems.