• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.674-677
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• 2002

In this paper, two kinds of windmill type motors which have a disk shape and a ring shape piezoelectric ceramics were studied. And characteristics of two models were compared with each others. A windmill type ultrasonic motor is composed of a stator, a rotor, and a ball bearing. The stator is made of a piezoelectric ceramics and two metals endcaps. When the piezoelectric ceramics vibrate, displacement of torsonal vibration appear at metal endcaps. The motor with 11.0[mm] diameter was studied by finite element analysis. The voltage of 100[V] was supplied at each model. Resonance frequency of 206.875[KHz] was obtained at the disk type, but ring type was 137.562[KHz]. The maximum torsonal displacement of $1.112[{\mu}m]$ was obtained at the disk type, but ring type was $1.698[{\mu}m]$.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.316-320
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• 2000

An ultrasonic linear motor was composed of a slider and a stator vibrator including piezoelectric material and elastic material. The ultrasonic linear motors mainly consist of an ultrasonic oscillator which generates elliptical oscillations. Elliptical oscillations are generated by synthesizing two degenerated modes. The design of a stator for an Ultrasonic linear motor was optimized with respect to vibration mode and direction of vibratory displacement by employing the finite element method. The motors were designed by varying the width of stator vibrator and the thickness, the length and the position of piezoceramics.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.411-414
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• 2000

An ultrasonic linear motor was composed of a slider and a stator vibrator including piezoelectric material and elastic material. The ultrasonic linear motors mainly consist of an ultrasonic oscillator which generates elliptical oscillations. Elliptical oscillations are generated by synthesizing two degenerated modes. Direction of vibratory displacement was analyzed by employing the finite element method. So, we could recognize that the direction of the slider's movement was controlled by changing the Phase difference of the drive voltage.

• Electrical & Electronic Materials
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• v.10 no.9
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• pp.889-894
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• 1997

A miniaturized wind-mill type ultrasonic motor which has diameter in 12.7 mm and thickness in 2.0mm using PMN-PZT piezoelectric ceramics was fabricated. The wind-mill type ultrasonic motors has only three plate and of two wind-mill shape slotted metal endcaps a rotor whose end is hollowed out so that its periphery fits with the shape of the stator and a bearing to guide the rotor. A Finite Element Analysis was carried out to obtain the endcaps behavior under a radial displacement change of piezoelectric disk and to optimize the structure of the number of slots. Increasing the applied voltage the revolution speed of ultrasonic motors was increased. The maximum speed of 700 rpm and the maximum torque of 0.22 nN·m of the wind-mill type ultrasonic motors were obtained.

• Journal of the Korean Ceramic Society
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• v.40 no.10
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• pp.981-984
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• 2003

A novel linear ultrasonic motor for precision position control was designed and fabricated. It was composed of two piezoelectric actuators with longitudinal ultrasonic fluctuations and shaking beam. When two AC electric fields (Usinwt, Ucoswt) were applied to piezoelectric actuators respectively, the middle part of shaking beam had an elliptical trajectory. According to experimental results, the generative force was proportional to pre-load force but the speed of slider was in inverse proportion. And the bar of shaking beam had a same trajectory with simulation result.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.79-82
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• 2002

In this paper, a single phase driven piezoelectric motor design was presented for linear motion. Two metal/ceramic composite actuators, a piezoelectric ring which was bonded to a metal endcap from one side, were used as the active elements of this motor. The motor was composed of a piezoelectric ceramic, a metal ring which has 4 arms, and a guider. Motors with 30.0[mm] and 35.0[mm] diameter were studied by finite element analysis and experiments. As results, the maximum speed of motor was obtained at resonant frequency. When the applied voltage of the motor increased, the speed was increased. Also, bidirectional motion of the motor was achieved by combining two motors which have different resonant frequency.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.204-207
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• 2000

An ultrasonic linear motor was composed of a slider and a stator vibrator including piezoelectric material and elastic material. The ultrasonic linear motors mainly consist of an ultrasonic vibrator which generates elliptical oscillations. L$_1$-B$_4$ ultrasonic linear motor use longitudinal and bending multi-vibration. In order to low driving voltage and improve the life time of the ultrasonic oscillator, we used stacked piezoceramics. Stacked piezoceramics are adhered to aluminum elastic material. The finite element method was used to optimize dimension of ultrasonic vibrator and direction of vibratory displacement. As a result of estimating the characteristics of the ultrasonic linear motor, no-load velocity was 2.04[m/s] when applied voltage was 70[V$\sub$rms/] in resonance frequency.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.85-88
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• 2004

The piezoelectric ceramic is attached between 'L' type guide and 'L' type stator, This motor has rotary motion which is operated by longitudinal and bending mode. The basic structure of the two kinds of type motor that called one stator motor, two stator motor is same but we suggested a few parameters for considering their stator design and characteristics. As a result, the two stator type motor is much more useful than one stator type motor for hi-direction rotation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.08a
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• pp.80-83
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• 2002

In this study, a single phase driven piezoelectric motor design is presented for linear motion-metal/ ceramics composite structure. Using ANSYS finite element analysis software, mode shape of free motor was obtained to clarify the working principle of this motor. And characteristics of the motor was measured. The motor is composed of a piezoelectric ceramic, a metal ring which has 4 arms, and a guider. The motor with 25.0[mm] diameter was studied by finite element analysis and experimentation too. As a result, the motor was expressed the best speed in resonance frequency. And according as voltage of the motor increase, the speed increased by ratio.

• Journal of IKEEE
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• v.13 no.3
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• pp.32-38
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• 2009

Ultrasonic motor (USM) is a new type motor which is driven by the ultrasonic vibration of piezoelectric elements. It possess many useful features that electromagnetic motors do not have, such as low speed and high torque. However, ultrasonic motor has heavy nonlinear speed characteristics and is sensitive to the change of drive conditions. In order to solve these problems, we present a smooth position control scheme for ultrasonic motor using fuzzy logic control with human expertise and without the need of any precise mathematical model. A "smooth operation" consideration is included when constructing the fuzzy rule base in order to achieve a most smooth response. An experimental position control system is constructed to show the effectiveness of the proposed control scheme.