• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 Techno-Fair 및 추계학술대회 논문집 전기물성,응용부문
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• pp.175-176
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• 2008

An ultrasonic motor of high torque with a new configuration for application in automobiles is proposed. The newly designed stator is two sided vibrator consisting of a toothed metal disk with a piezoelectric ceramic ring bonded on both faces of the disk which generates a flexural traveling wave along the circumference of disk. In this configuration, the displacement on the surface of stator may not be confined. It also produces a large vibrating force and amplitude because the vibrator is sandwiched by two piezoelectric plates. It is possible to increase the torque by improving the vibration characteristics. To compute the vibration mode of the motor of diameter 48 mm, the finite element method was used. A 6th mode was chosen as the operation mode with a resonance frequency of about 64.4 kHz. According to this design and measured its performance, a prototype was fabricated. The performance measurement of the prototype motor showed that its stall torque was about 1.8 Nm and efficiency was 37 % at 60 % of the maximum torque.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.228-229
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• 2006

본 연구에서는 초음파 모터 등의 고출력 액츄에이터에 응용 가능한 $04Pb(Ni_{1/3}Nb_{2/3})O_3-6Pb(Zr_xTi_{1-x})O_3$ 조성시스템에 소결온도를 달리하여 압전, 유전특성 및 미세구조에 관해 고찰하였다. 본 조성을 $1200^{\circ}C$ 온도에서 2, 4, 6, 8시간 소결하여 시편을 제조하였으며 이의 결정구조 및 미세조직을 분석하였다. 소결시간 증가에 따라 전기기계결합계수와 기계적품질계수는 증가하였으며, 압전상수는 Zr(Zr+Ti)비 0.390까지 증가하였으나 그 이상 증가함에 따라 감소하였다. 압전특성은 $1200^{\circ}C$에서 4시간 소결한 Zr=0.390인 조성에서 ${\varepsilon}_r$ = 4487, $k_p$ = 0.72. $d_{33}$ = 710, $Q_m$ =109의 우수한 특성을 나타내었다.

• 재활복지공학회논문지
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• 제5권1호
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• pp.103-110
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• 2011

본 논문에서는 지능형 휠체어를 위한 시선 인식 인터페이스에 대해 제안한다. 시선 인식 인터페이스는 조이스틱을 움직이기 힘든 중증 장애인을 위해 시선 인식 및 추적을 이용하여 전동휠체어를 움직일 수 있게 하는 사용자 인터페이스이다. 지능형 휠체어는 시선인식 및 추적 모듈, 사용자 인터페이스, 장애물 회피 모듈, 모터 제어 모듈, 초음파 센서 모듈로 구성된다. 시선인식 및 추적 모듈은 적외선 카메라와 두개의 광원으로 사용자 눈의 각막 표면에 두 개의 반사점을 생성하고, 중심점을 구한 뒤, 동공의 중심점과 두 반사점의 중심을 이용하여 시선을 인식하고 추적 한다. 제안된 방법의 시선 인식 인터페이스는 실험을 통해 시선을 이용하여 지능형 휠체어에 명령을 하달하고 지능형 휠체어가 임의로 설치된 장애물을 감지하고 정확하게 장애물을 회피 할 수 있음을 보였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.2
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• pp.664-668
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• 2003

Transducer for ultrasonic linear motor with the symmetric and anti-symmetric modes was studied. The ultrasonic linear motor consists of two Langevin type piezoelectric vibrators that cross at right angles with each other in tip. In order to excite symmetric and anti-symmetric modes, the transducer must have a phase shift of 90 degree in space and time. Therefore, the tip of transducer moves on an elliptical motion. In this paper, the finite element analysis was used to optimize dimension and displacement of the transducer. The ultrasonic motor was fabricated using the simulated result and the driving characteristics were measured. No-load velocity was 0.28[m/s] and the maximum efficiency was 30[%] in resonance frequency.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.2
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• pp.636-640
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• 2003

As industrial technology was developed, necessity for small size motor was increased on various fields such as medical treatment and robotics. The motor should be simple structure, and it has easy process of manufacture to overcome the limit of miniaturization. So, "the windmill type ultrasonic motor" is enough to satisfy these conditions. In this paper, windmill type ultrasonic motor which was proposed by B.Koc and K.Uchino, was analyzed and fabricated with modified endcap shape. Displacements of arms of the proposed endcap were compared with the previous endcap, using the finite element analysis program (ANSYS). Better rotational characteristics was expected in proposed model as result of FEA. Experimentally, rotary motors of 3.5 [cm] diameter were fabricated, and the speed and torque of the motor were measured. As a result, speed and torque were changed in proportion to the electrical input voltages. And low efficiency which was different from an expectation was obtained in this motor. So, various problems should be improved for practical use.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 영호남학술대회 논문집
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• pp.53-56
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• 2000

Piezoelectric ceramics can provide electro-mechanical transduction with high stresses but low displacement. To obtain larger displacements, several mechanical amplifying structures have been used. High alternating displacements can be obtained using resonant structure. In this paper, we designed a bolt-tightened Langevin type ultrasonic vibrator whose resonant frequency is 50[kHz] and ceramics are multilayered. FEM(Finite Element Methode) was employed to calculate. the resonant frequencies and maximum displacements of designed vibrators. The designed resonant frequency and computer calculated frequencies were coincided. When input voltages were increased, the maximum displacements also rose. As AC voltage was applied, the maximum displacement were shown sinusoidal changes. Terminal input admittance over a frequency range spanning the resonant frequency were calculated. ANSYS was used to find resonant frequencies and calculate displacements of vibrators.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.319-319
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• 2010

The previous cross type USM(ultrasonic motor) has the stator of cross shape composed of 8 ceramics. However, ultrasonic motor with simple structure has the stator composed of only 4 ceramics. Principle of the motor is to apply alternative voltages which have 90 phase difference to attached ceramics, and then elliptical displacement is generated at four edges of elastic body. Characteristics of the motor were simulated by FEM(finite element method). The parameters were size of the stator and thickness of the ceramics. According to FEM results, driving frequency of motor is defined at 28 [kHz]. On the contrary, driving frequency of fabricated motor is defined at 26.8 [kHz] and then, experimental results were compared with FEM results at the frequency. As a result, elliptical displacement and speed of USM increased linearly with increasing applied voltage.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.320-320
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• 2010

In the case of existing ultrasonic motors, they have characteristics such as outstanding response speed, speed and high efficiency. However, it's very hard to use practically them as small motors due to complicated structure and expensive cost. This paper proposed v-type ultrasonic linear motor. Stator of the motor is composed of thin elastic body and four ceramics attached to upper and bottom areas of the body. The ceramics have each direction of polarization. When two harmonic voltages which had $90^{\circ}$ phase difference were applied to the ceramics, the symmetric and anti-symmetric displacements were generated at the tip to make the elliptical motion. To find out a model that generates maximum displacement at contact tip, FEM program was used with change of leg-angle. In addition, optimal model was chosen by considering magnitude and shape of displacement according to change of frequency.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.187-188
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• 2008

An ultrasonic motor of high torque with a new configuration for application in automobiles is proposed. The newly designed stator is a two sided vibrator consisting of a toothed metal disk with a piezoelectric ceramic ring bonded on both faces of the disk which generates a flexural traveling wave along the circumference of disk. In this configuration, the displacement on the surface of stator may not be confined. It also produces a large vibrating force and amplitude because the vibrator is sandwiched by two piezoelectric plates. It is possible to increase the torque by improving the vibration characteristics. To compute the vibration mode of the motor of diameter 48 mm, the finite element method was used. A 6th mode was chosen as the operation mode with a resonance frequency of about 64.4 kHz. According to this design and measured its performance, a prototype was fabricated. The performance measurement of the prototype motor showed that its stall torque was about 1.8 Nm and efficiency was 37% at 60% of the maximum torque.

• 제어로봇시스템학회논문지
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• 제6권4호
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• pp.327-332
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• 2000

In this paper, a new multi-fingered robot hand using ultrasonic motors and its control system are developed. The developed robot hand has four fingers and fifteen articulated joints. The distal joint of each finger is directly driven by ultrasonic motor and all joints except the distal joint has low transmission gear mechanism with the motor. The developed robot hand has several advantages in size compared to a hand using conventional DC motors, and in performance compared to a hand using tendons to drive joints. A VME-bus based hand control system and ultrasonic motor driver are also developed. The performance of the hand is confirmed by using the developed control system in real-time.