• 전력전자학회논문지
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• 제3권3호
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• pp.165-172
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• 1998

USM의 전기 기계적인 변환은 USM의 고정자에 정렬된 PZT트랜듀서를 구동하기 위한 2-상 고주파 전력 변환부와 고정자와 회전자 사이에 마찰력을 변환하는 기계적인 트러로써 나눠지며 이러한 구조특성 때문에 온도에 의한 비선형 특성이 내포하게 된다. 초음파 모터의 외함의 온도가 +2$0^{\circ}C$~3$0^{\circ}C$에서는 정상적인 특성을 나타내지만 장시간의 운전에 의한 모터의 마찰열에 의해 온도증가는 구동주파수, 구동전류, 속도의 감소를 가져온다. 현재 사용되고 있는 초음파 모터는 온도에 대한 보상이 이뤄지지 않고 있다. 본 논문에서는 퍼지제어 기법을 통해 초음파 모터의 운전중 외함의 온도증가에 따른 속도 보상용 시스템을 제안한다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.585-588
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• 2002

The USM uses friction between a mobile part (rotor) and a vibration part(stator), which is different from the principle of the conventional motor based on the interaction of electric and magnetic fields. In this thesis, a flat-type $L_1-B_8$ mode USM was designed and fabricated the characteristics of an ultrasonic vibration. The results of fabricated USM are as follows: (1) In case of ultrasonic motor with elastic-body of stainless, when applied voltage, frequency, pressing force of rotor were 50 [V], 27.9 [kHz], 1.5 [N], 5.0[mN m] respectively, the speed of revolution could be presented up to 0 [cm/s]. (2) In case of ultrasonic motor with elastic-body of brass, when applied voltage, frequency, pressing force of rotor were 50 [V], 21.4 [kHz], 1.5 [N], 1.4[mN m]respectively, the speed of rotor revolution was presented up to 0 [cm/s]. (3) The USM of elastic-body of stainless showing 1.17[%], somewhat low, in the maximum efficiency according to torque was superior to the USM of elastic-body of brass showing 0.34 [%]. The Flat-type $L_1-B_8$ mode USM had characteristics of typical drooping torque-speed, large torque and high speed, and operating in both directions by phase reversal.

• Journal of Power Electronics
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• 제6권1호
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• pp.38-44
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• 2006

In this paper, a speed sensorless control for an ultrasonic motor (USM) using a neural network (NN) is presented. In the proposed method, rotor speed is estimated by a three-layer NN which adapts nonlinearities associated with load torque and motor temperature into control. The intrinsic properties of a USM, such as high torque for low speeds, high static torque, compact size, etc., offer great advantages for industrial applications. However, the speed property of a USM has strong nonlinear properties associated with motor temperature and load torque, which make accurate speed control difficult. These properties are considered in designing a control method through the application of mathematical models. In these strategies, a detailed speed model of the USM is required which makes actual applications impractical. In the proposed method, a three-layer NN estimates the speed of the USM from the drive frequency, the root mean square value of input voltage and the surface temperature of the USM, where no mechanical speed sensor is needed. The NN speed based estimator enables inclusion of variations in driving conditions due to input signals of the NN involved during the driving state of the USM. The disuse of sensors offers many advantages on both the cost and maintenance front. Moreover, the model free sensorless control method offers practical controller construction within a small number of parameters. To validate the proposed speed sensorless control method for a USM, experiments have been executed under several conditions.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 F
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• pp.2151-2155
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• 1998

The traveling wave type ultrasonic motor(USM) has no electro-magnetic circuits( coil or core). The driving principle of the USM is based on high-frequency mechanical vibrations and frictional force. The USM, thus, is fed by two-phase high - frequency sinusoidal inverter using its series resonant parasitic components. For the using of series resonant type inverter, it should be needed to a USM parasitic capacitance and a proper inductor chosen. In this paper, the values of optimal inductance are designed and the efficiency of USM drives is achieved. The effectiveness of the proposed design is demonstrated by experiments.

• 한국IT서비스학회지
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• 제11권1호
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• pp.141-153
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• 2012

USM(Unit Service Management System) is the development tool and methodology to handling the event process in a U-City integrated platform by using the minimum unit services. USM can be one of the SOA development methodology. Minimum unit service has a minimum business logic that can be executed with input and output parameters. Minimum unit service consists of three parts : service profile, service input and output parameters and service execution information. USM provides two types of the execution method. One is module execution and the other is web service execution. The development of the event sinario by the USM development methodology can reduce the cost and duration of the u-service development by raising the rate of reusing minimum unit service.

• 소성∙가공
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• 제13권3호
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• pp.253-261
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• 2004

The machining technology for the brittle materials such as ceramics are applied to the fields of MEMS(micro electromechanical system) by the progress of new machining technologies such as Etching, Diamond machining, Micro drilling, EDM(Electro discharge machining), ECDM(Electro discharge machining), USM(Ultrasonic machining), LBM(Laser beam machining), EBM(Electron beam machining). Especially, the USM technology can be applied to the dieletric brittle materials such as silicon, borosilicate glass, silicon nitride, quartz and ceramics with high aspect ratio. The micro machining system with machining force controlled position servo is developed in this paper and the optimized ultrasonic machining algorithm is constructed by the force controlled position servo control. The load cell is adapted in the force measuring and the servo control algorithm, suit for the ultrasonic machining characteristics, is estabilished with using the PID auto-tunning functions at the PMAC system which is generally adapted in the field of robot industries. The precision force signal amplifier is constructed with high precision operational amplifier AD524. The vacuum adsorption chuck which is made of titanum and internal flow line is engraved, is used in the workpiece fixing. The mahining results by USM shows that there are some deviation between the force command and the actual machining force that the servo control algorithm should be applied in the machining procedures. Therefore, the constant force controlled position servo system is developed for the micro USM system and by the examination machining process in USM, the stable USM system is realized by tracking the average value of machining force.

• 천문학회보
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• 제37권2호
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• pp.160.2-160.2
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• 2012

Unified State Model(이후 USM)은 Altman(1972)에 의해 처음 제안된 이후 Chodas(1981), Raol & Sinha(1985), Vittaldev et al.(2012) 등을 거치며 연구 발전되어 왔다. 이 모델은 공간상 6개 성분의 위치, 속도 벡터를 이용해 위성의 운동을 기술하는 기존 계산 방법과 달리 4개의 Quaternion 변수를 도입하여 위성의 위치를, 3개의 Hodograph 변수를 도입하여 위성의 속도를 각각 기술한다. USM의 장점은 직교좌표계로 표현된 위성의 위치, 속도 변수에 비해 USM 변수의 변화량이 상대적으로 작기 때문에 수치 계산 시 계산의 안정도가 높다. 또한 원궤도(${\omega}$ : undefined)와 적도면 궤도(i = 0, ${\Omega}$ : undefined) 계산 시에 나타나는 특이성(singularity) 문제가 발생하지 않는다. 본 연구에서는 USM 계산방법과 기존 방법에 의한 위성궤도 계산결과의 차이를 비교 분석하였다. 지구궤도 위성의 정밀계산을 위해 이체항 이외에 지구타원체 섭동항과 대기 항력에 의한 섭동항을 추가 적용하였다. 비구형 지구 중력 포텐셜에 의한 섭동은 J4항까지 고려하였으며, 대기 항력은 간단한 exponential 모델을 적용하였다. 또한 수치계산 시 적분 간격과 정밀도 차수를 조절하여 각 모델의 계산 안정성을 테스트하였다. 본 연구의 궤도계산 결과 USM 모델을 이용한 계산방법은 그 정밀성과 계산효율성이 매우 우수한 것으로 검증되었다.

• 전기학회논문지P
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• 제52권1호
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• pp.20-27
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• 2003

In this study, we designed and made Ultrasonic motor-digital multi controller(USM-DMC) using FPGA chip, A54SX72A made in Actel Corporation. By the minute, USM-DMC can adjust the frequency, duty ratio, and phase difference parameters of USM by digital input to be each 11bit from PC. Therefore, when we use this controller, it is possible to apply typical three parameters individually as well as multi-parameters simultaneously to control the speed and the torque. What is more, the strongest point is that it can trace frequency based on optimized frequency as compared with the phase difference because we can input optimized resonant frequency while in motoring. And we test the speed of USM with the adjustment of multi-parameters, the phase difference-frequency. As the result of the test, in the case of the multi-parameters of the phase difference and frequency, the speed characteristic is more linear and stable, and wider in the range of control than the single-parameter of the phase difference or the frequency.

• 한국조명전기설비학회지:조명전기설비
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• 제10권6호
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• pp.88-95
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• 1996

초음파 모터(ultrasonic motor : USM)는 압전 세라믹소자(piezoelectric ceramics)의 초음파 진동을 이용한 마찰 구동형 모터이다. 기존의 전자식 모터와는 달리 자기화로 즉 철심과 코일이 없는 단순 구조를 갖는 특수 소형 모터로서 저속 고토오크의 특성을 지니고 있으므로 다이랙트 드라이브 방식의 액츄에이터로 활용이 가능하다. 그리고 자장이 강한 특수 환경에서도 외란의 영향을 받지 않아도 산업계 전바에 걸쳐 제어용 모터로서 높이 평가받고 있다. 따라서 실용화를 위한 여러 가지 파라미터에 대한 특성 실험과 그에 따른 제어법 개발이 시급하다. 본 논문에서는 2상 입력 전원의 전압차 제어(voltags)를 제안한다. 먼저 전압차 제어에 의하여 이론적으로 고찰하고 초음파 모터의 구동원이 되는 고정자의 한 질점에서 발생하는 타원 궤적을 시뮬레이션을 통하여 알아봄으로써 초음파 모터의 속도와 토오크 특성을 예측하였다. 그리고 입력 전압워 전압차를 조절하여 초음파 모터의 속도와 토오트 특성을 실험하였다. 그 결과를 토대로 전압차 제어가 초음파 모터의 새로운 구동 방식이 될 수 있음을 밝혔다.

• Asian Pacific Journal of Cancer Prevention
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• 제16권17호
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• pp.8015-8015
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• 2015