• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.664-667
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• 2001

A flat-type L$_1$-B$_{8}$ Mode Ultrasonic motor(USM) uses longitudinal-bending multi-mode vibrator which is constructed with the metal-piezoceramic composite thin plate vibrator. Especially, the characteristics of vibrating displacement of the vibrator are important for the fabrication of USM. So, in this study, we tried to analyze them by the FEM(finite element method) simulation program. ANSYS 5.6 we used is a finite element software enabling the analysis of 2 or 3 dimensional structure of piezoelectric materials. Using this made us analyzing the resonance frequency and calculating displacement of vibrator and then the position of the projection.n.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.11
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• pp.2723-2731
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• 2000

Ultrasonic motors(USM) has been emerging as one type actuators, which possess many advantages such as high torque, low weight, compact size and no magnetic field generation. In spite of these features, there are several problems to be solved, which are temperature rise in case of long term operation, non -linearity, and hysteresis. Among these, hysteresis cause the most serious problem in force/torque control applications. To cope with this paper we propose a new PWM driving method which can be applied to force/torque control applications. To cope with this problem, in this paper we propose a new PWM driving method which can applied to force/torque control of USM. To verify the proposed method, an experimental setup was built and several experiments were performed.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.328-330
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• 1994

The Ultrasonic motor(USM) has many good characteristics such as high torque at low speed range, large holding torque based upon frictional force, high speed response, flexible free ferns, compactness in size, low magnetic noise and silentness in motion. Because of having low speed rotation, USM is good as an actuator of a small size direct drive (DD) manipulator. The acturators for the DD manipulators must have good controllability on the speed and torque from zero to maximum value continuously. New method was developed for speed and torque control by the phase difference control of the two-phase driving signals of the motor. Then rule adjustable compliant and dumped motion was realized on the output shaft of the motor by PD control of the output shaft angle.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.7
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• pp.133-140
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• 2002

Ultrasonic Machining (USM) is widely used in cutting of non-conductive, brittle workpiece materials such as engineering ceramics. However, USM has a limitation in its application to micro machining because problems are occurred in attaching micro tools to the machine and maintaining high precision. Therefore Micro Ultrasonic Machining (MUSM) with WEDM is proposed in this research. The experiments are produced as the change of shaft diameter and abrasive size.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2003.12a
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• pp.253-256
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• 2003

현재 IETF RFC 3414에서 제안한 SNMP 메시지 인증 및 기밀성 서비스용 키 분배방식은 관리자의 패스워드를 기반으로 국지 키를 생성하는 알고리즘을 사용한다. 이는 관리자의 패스워드 노출 방지를 위해 관리자가 지리적으로 분산된 SNMP 관리객체 (Managed Agent)를 순회하면서 설치해야 한다는 문제점과 또한 관리객체에 SNMP 메시지를 전송되는 시점에서 국지 키가 계산되어 SNMP 메시지의 전송지연 문제점을 내포하고 있다. 본 논문에서는 누구나 관리객체 설치가 가능하고 SNMP 메시지 전송지연을 제거할 수 있도록 SNMPv3 USM에 Diffie-Hellman 키 분배 방식을 적용하는 방안을 제안하였다. 제안된 방식은 RFC 3414와 동일한 수준에서 SNMP 메시지 인증 및 기밀성 서비스를 제공한다.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.866-867
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• 2007

최근의 소형화 추세에 따라 소형 액추에이터에 대한 수요가 늘고 있다. 여러 가지 액추에이터 중 특히 초음파 모터(USM)는 소형화하기에 용이한 특성을 가지고 있다. 지금까지 USM의 contact mechanism에 대한 수많은 연구가 있었지만, 아직 확립된 해석방법이 존재하지 않는다. 본 논문에서는 수치적 방법과 해석적 방법을 결합하여 지름 9[mm]의 링타입 회전형 초음파 모터(RUSM)를 분석하였다. 이 방법을 사용함으로써 모터의 특성을 쉽고 빠르고 정확하게 분석할 수 있다. 분석된 결과는 실험 결과와 비교함으로써 검증하였다.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.39-41
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• 1995

The inherent performance of Ultrasonic Motor(USM) which is on of highlighted a directly-driven positioning servo motor/actuator. In this paper, the speed of control USM based on neural network control. The neural network control can roughly be classified as the direct control and indirect control schemes. An indirect control scheme is adopted for Ultrasonic Motor speed control. A back propagation algorithm is used to train neural network controller. The Simulation results show that this neural network control system can provide good dynamical responses.

• The Bulletin of The Korean Astronomical Society
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• v.32 no.1
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• pp.44.1-44.1
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• 2007

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.2
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• pp.213-218
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• 2013

Ultrasonic machining (USM) is a new method used in metal cutting. This process does not involve heating or any electrochemical effects, causes low surface damage, has small residual stress, and does not rely on the conductivity of the workpiece. These characteristics are suitable for the machining of brittle materials such as glass or ceramics. However, the use of USM for brittle materials generates cracks on the workpiece. Therefore, in this study, Taguchi's method was used to optimize the processing conditions of micro holes drilled in glass and ceramics. This method was used to successfully reduce the number of cracks at the entrance and the exit of the micro holes.

• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.6
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• pp.500-509
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• 2007

In this paper, we propose a novel pc-based 8-channel USB interface digital multi-controller (DMC) has capacity to be able to adjust ultrasonic motor's (USM's) the parameters-frequency, amplitude, phase difference using FPGA. The proposed DMC can control parameters directly by digital logic through a FPGA. Since it has counter circuit for rotary encoder to measure position and velocity of USM, the other separate circuits are unnecessary. Therefore, it could reduce the size of controller and the production cost. Finally, to verify the performance of proposed DMC, we tested the speed characteristic of two types USM with no-load as adjusting the parameters.