• 대한기계학회논문집
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• 제18권6호
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• pp.1374-1381
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• 1994

This study suggests a new type shaft generating system driven by hydrostatic transmission suitable for small size vessels. In this system, the hydraulic motor speed is controlled by displacement adjustment using a 3-way high speed on/off valve. The 3-way high speed valve is operated by PWM control signal. In this study, a digital robust servo control algorithm is applied to the controller design of the system. By experiments and numerical computations, the frequency variation characteristics of the generating system under various disturbances are investigated. Conclusively, it is said that the shaft generating system proposed in this study shows excellent control performances.

• 대한전기학회논문지:시스템및제어부문D
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• 제51권10호
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• pp.477-482
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• 2002

One of the key technologic requirements for rotary blood pumps is the sealing of the motor shaft. A mechanical seal, a journal bearing, magnetic coupling, and magnetic suspension have been developed, but they have drawbacks such as wear, thrombus formation, and power consumption. A magnetic fluid seal is durable, simple, and non power consumptive. Long-term experiments confirmed these advantages. The seal body was composed of a Nd-Fe-B magnet and two pole pieces; the seal was formed by injecting magnetic fluid into the gap (50${\mu}m$) between the pole pieces and the motor shaft. To contain the ferro-fluid in the seal and to minimize the possibility of magnetic fluid making contact with blood, a shield with a small cavity was attached to the pole piece. While submerged in blood, the sealing pressure of the seal was measured and found to be 31kPa with magnetic fluid LS-40 (saturated magnetization, 24.3 KA/m) at a motor speed of 10,000 rpm and 53kPa under static conditions(0mmHg). The specially designed magnetic fluid seal for keeping liquids out is useful for axial flow blood pumps. The magnetic fluid seal was incorporated into an intra-cardiac axial flow blood pump.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 추계학술대회 논문집
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• pp.229-230
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• 2009

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 추계학술대회 논문집
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• pp.428-432
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• 2004

The important problem in the high speed spindles is to reduce and minimize the thermal effect by the motor and ball bearings. Thermal characteristics according to the bearing preload and hollow shaft cooling are studied for the test spindle with the oil mist lubrication and high frequency motor. Bearings and motor e main heat generation, and heat generation by ball bearings as a function of load, viscosity and gyroscopic moment effect are considered. Temperature distribution and thermal displacement according to the speed of spindle are measured by thermocouple and gap sensor. The results show that the fitting preload and hollow haft cooling are very effective to minimize the thermal effect by the motor and ball bearings.

• 한국해안·해양공학회논문집
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• 제22권5호
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• pp.326-332
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• 2010

해수 임펠러샤프트의 각종 하중에 의한 파단과 이를 개선하기위한 재설계는 정적, 동적 해석을 통한 원인분석과 유한요소법을 이용하여 효과적으로 수행할 수 있다. 본 논문에서는 전형적인 임펠러 샤프트의 파손에 대한 원인 분석을 수행하고 관련된 재설계기법을 제시하였다. 일차적으로 정적구조해석을 수행하였고 다음으로 구조물의 외력과의 공진문제를 포함한 동적해석을 수행하였다. 구조해석은 ANSYS코드를 사용하였으며, 결과적으로 파단원인을 찾아 분석하였다. 주된 파단원인은 과도한 굽힘모멘트의 발생과 응력집중, 구조물의 외력과의 공진에 의한 것으로 분석되었다. 해수 임펠러샤프트의 파단과 관련된 재설계기법의 이론적 배경을 정립하였으며, 재설계기법의 적용성과 정적, 동적 샤프트 재설계에 대한 유용성을 제시하였다.

• 동력기계공학회지
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• 제6권3호
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• pp.36-41
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• 2002

A swashplate type piston motor with a tripod joints is introduced to improve compactness and starting torque in conventional types of motor. If the driving torque of motor shaft is transmitted by utilizing the mechanism, its friction torque loss would be drastically reduced and mechanical efficiency would be improved because the lateral force on the piston of the rod type motor with tripod joints mechanism is relatively smaller than that of the conventional plunger type motor. In particular, kinematics analysis for the mechanism are done as a preliminary study to investigate the feasibility of the mechanism in the axial piston motor. General formulas are derived from the displacement and velocity analysis of the mechanism, showing relationships between output shaft and shoe holder motion. A series of numerical calculations are carried out for a medium size motor with 160cc/rev using the formulas and their graphical plots are shown as well.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2002년도 학술대회논문집
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• pp.339-342
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• 2002

In the industrial motor drive system which is composed of a motor and load connected with a flexible shaft, a torsional vibration is often generated because of the elastic elements in torque transmission. To solve this problem H$_{\infty}$ controller was designed. In this paper, H$_{\infty}$ control of 2-mass system using H$_{\infty}$ filter for compensating shaft torque is proposed. Pole-zero maps show the validity of proposed controller.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1147-1152
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• 2004

Switched Reluctance Motors have an inexpensive, intrinsic simplicity and low cost that makes them well suited to home appliance and office applications. However the motor suffering with necessity of shaft position sensor, lead to non-linearity of operations. Further, the involvement of static converters deteriorates the operational power factor. Implementation of a sensorless algorithm, can remove the need of position sensors. Also, the drive includes a compact power factor control in the input stage by implementing Zero Current Switching Quasi-Resonant Boost Technology. This paper presented, aims at optimized low line current distortion, high power factor, low cost and a shaft position sensorless Switched Reluctance Motor drive.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.42-45
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• 2002

In the two-mass motor drive system driving a load through a flexible shaft or transmission system, a shaft torsional vibration is often generated. The overshoot of the motor drive system easily causes vibration. In this case I-PD controller has been generally used in speed control, because of the simplicity of structure. This paper using an analytical pole assignment design, proposes the overshoot formulas, and the settling time formula. The objective of this paper is to provide a design method of I-PD controller by using overshoot formulas, and settling time formula. The simulation results show that we can design the controller with desired overshoot and settling time.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 A
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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.