• The Transactions of the Korean Institute of Power Electronics
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• v.3 no.3
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• pp.165-172
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• 1998

The electromechanical energy conversion conditioning and processing implementation in USM direct motion control system is generally divided into two power stages: the two-phase high-frequency ac power inversion stage for driving piezoelectric ceramic PZT transducer array off the USM stator and the mechanical thrust power conversion stage based on the frictional force between the piezo electric stator array and the rotary slider of the USM. However, the dynamic and steady-state mathematical modeling of the USM is extremely default from a theoretical point of view because it contains many complicated an nonlinear characteristics dependant on operation temperature. In +2$0^{\circ}C$~3$0^{\circ}C$, the operating characteristics of the USM has represented normal condition. But the other temperature, it has abnormal condition so that driving frequency, current and motor speed will be down. The recent USM has controller without temperature compensation. This study represents the fuzzy controller for speed compensation according to operating temperature by driving frequency.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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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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• v.6 no.1
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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.

• Proceedings of the KIEE Conference
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• 1998.07f
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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.

• Journal of Information Technology Services
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• v.11 no.1
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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.

• Transactions of Materials Processing
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• v.13 no.3
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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.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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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.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.52 no.1
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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.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.10 no.6
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• pp.88-95
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• 1996

The ultrasonic motor(USM) has good characteristics such as compact size, silent motion, high speed responce, low speed and high torque. The USM is driven by 2-phase AC electricity. The control parameters of USM are voltage, phase, and frequency of input powers, etc. In this paper, a voltage difference control is proposed. The voltage difference control has more advantage than phase difference control. Specially, current and power is lower than that of phase difference control. For this voltage diffrence control, we designed USM controller to adjust volatage and phase using PLSI(Programmable Large Scale Integration).

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.17
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• pp.8015-8015
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• 2015