• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.2
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• pp.822-827
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• 2013

In this paper, how to stop a moment to experiment with stop function, electric brake type scale model propulsion system is designed and fabricated by control of the braking torque is proposed. Scale model system for motor-driven, inertial load, the structure of the load for the motor and the inverter system was constructed with two sets of converters, the actual range of the rotational speed of the vehicle DDM experiments to be able to. In Additional, observer to estimate the rotor position and speed of using resolver, and the pole at low speed, speed detection methods have been developed. As a result of this study, first, stop the moment Second, the reduction of braking torque, and how to initiate the operation of the air brake blending by using the braking, improve braking methods that only use the electric brake to stop brought.

• KSTLE International Journal
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• v.4 no.1
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• pp.18-26
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• 2003

Recently, fluid dynamic bearings (EDBs) have important applications in miniature rotating machines such as those found in the computer information storage industry, due to their outstanding low acoustic noise and NRRO (Non-Repeatable Run Out) characteristics. This research investigates the dynamic behavior of fluid dynamic bearings composed of hydrodynamic herringbone groove journal and spiral groove thrust bearing. The five degrees of freedom of FDB are considered to describe the real motion of a general rotor bearing system. The Reynolds equation and five nonlinear equations of motion for the dynamic behavior are solved simultaneously, The incompressible Reynolds equation is solved by using the finite element method (FEM) in order to calculate the pressure distribution in a fluid film and the five equations of motion by using the Runge-Kutta method. The reaction forces and moments are obtained by integrating the pressure along the fluid film. Numerical results are validated by comparing with the previously published experimental and numerical results. As a result the dynamic behavior of FDB spindle such as orbit, floating height, and angular orbit is investigated by considering the conical motion under the static and dynamic load conditions.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.4
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• pp.361-366
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• 2015

In this paper, we propose a novel surveillance throwing robot which is compact, light-weight and has an efficient shock absorption mechanism. The throwing robot is designed in a spherical shape to be easily grabbed by a hand for throwing. Also, a motor-wheel linking mechanism is designed to be robustly protected from shocks upon landing. The proposed robot has a weight of 2.2kg and the diameter of its wheels is 150 mm. Through the field experiments, the designed robot is validated to withstand higher than 13Ns of impulse.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.10 no.5
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• pp.57-65
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• 1996

초고속 정전유도형 정전전동기의 개발의 위한 기초연구로서 회전자 물질의 표면저항률, 비유전율 및 전하완하시정수의 변화에 따른 회전자의 회전속도특성을 조사하였다. 회전자표층물질의 비유전율 및 표면저항률은 클수록 회전자의 회전속도는 증가하였으며, 또한 이 두 요소를 곱한 회전지표면에 유도된 전하의 완화시정수가 클수록 회전속도는 증가하였다. 한편 회전자표층물질로서 도전성물질(Ti)을 폴리프로필렌 위에 불연속적으로, 즉 띠의 모양으로 증착한 시료를 사용하여 띠의 폭 및 경사각의 변화에 따른 회전자의 회전속도특성 및 토크 특성을 조사하였다. 이 경우 띠의 폭이 적어질수록 회전자의 회전수는 지수함수적으로 증가하였으며, 등간격으로 세분화한 것을 회전자의 축에 대해서 회전방향으로 경사각$\theta$만큼 기울였을 때 $\theta$=60。 및 150。일 때 회전자의 회전속도가 가장 큰 것으로 나타났으며, 특히 경사각 $\theta$=0。일때에 비해서 약 125[%]정도 높은 회전속도를 보였다. 최대토크 및 최대출력은 각각 {{{{25$\times$ { 10}^{ -6} [Nm]}}}}및 11.5[mW]이었다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.300-300
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• 2007

최근 전기전자기기 및 광학기기 등의 소형화 및 고기능에 맞추어 구동 장치의 소형화가 필수적으로 요구됨에 따라, 보다 간단한 구조의 다양한 소형 압전 선형 모터에 대한 개발이 활발히 진행되고 있다. 본 연구에서는 굴곡 진동 모드를 갖는 평판형의 압전체와 탄성체로 구성된 압전 트랜스듀서와 두 개의 압전 트랜스듀서를 연결하여 타원 운동을 구현하기 위해, 굴곡 변형이 발생하는 한 쌍의 압전 트랜스듀서에 $90^{\circ}$ 위상차를 갖는 정현파를 각각 인가하여, 한 쌍의 압전 트랜스듀서를 연결하는 돌출부에서 타원궤적을 형성하는 소형 압전 액츄에이터를 설계하였다. 유한요소해석 프로그램인 ATILA를 이용하여 결합부의 타원 궤적의 형성하기 위한 압전 트랜스듀서의 최적 동작 주파수로 운동 모드를 결정하고자 한다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.791-798
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• 2001

As the form factor of the disk drive is decreased, many mechanical issues that are negligible in larger form factors, should be considered for the design of the miniature drives. This paper deals with basic research on vibration characteristics and design considerations of small disks and actuators. The natural frequencies of micro-sized disks with polycabonate and glass substrates are experimentally measured, being compared to FEM results. In order to investigate the effects of rotating speeds, airflow and disk size on power consumption. we measure power imposed to spindle motor when different optical disks are spins in vacuum chamber. Finally, The vibration characteristics of the micro actuator used in a IBM Microdrive are experimentally studied for the application to the basic design of micro optical disks.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.8
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• pp.3634-3641
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• 2012

This paper introduced a previous study which suggest ways to improve problems of drive control system of Ropeless Elevator when developing prior to commercialization of Ropeless Elevator. In particular, this study also manufactured motor, linear speed sensor and the miniature systems to study the implementation of the Ropeless Elevator drive. This study examined the problem of conventional PI controller through the speed control test and focused on the advanced controller based on disturbance observer for Ropeless Elevator drive. The results of this study confirmed the feasibility of the Ropeless Elevator and showed the satisfactory results of drive control techniques. This study also extracted many more problems that still need to be improved in the future for commercializing such as the sensor, high-performance controller, precision structures, safety devices and so on.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.16-20
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• 1989

In this paper, we describe the optimal driving method and magnetic flux distribution of permanent magnet which enhance torque characteristics in small-sized 3-phase brushless DC motors. The disadvantages of conventional $120^{\circ}$ constant current drive method are torque ripple, switching noise and spike voltage due to the inductance of stator coil. This shortcommings can be avoided by the switching slew-rate of driving current which is called linear voltage driving method. The aim of this study is to analyze linear voltage driving method quantatively and to determine optimal drive current waveform through computer simulation. The selection of commutation angle and slew rate of a new driving current at switching instants makes torque ripple index minimize and average torque maximize. And the validity of this new driving method was assured by Fourier analysis. Considering two dimensional nonlinear magnetic flux distribution on the permanent magnet, we suggest optimal flux distribution according to the presented driving method which improves torque characteristics.

• Annals of Clinical Neurophysiology
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• v.8 no.2
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• pp.125-134
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• 2006

Among the various physiological factors that affect nerve conduction velocity (NCV), temperature is the most important. Because the influence of temperature is the most important source of error. It is known from animal experiments that conduction is eventually completely blocked at low temperatures, the myelinated A fibers being the first affected and the thin fibers of group C the last. Many studies showed that the NCV decreases linearly with lowering temperature within the physiological range. The distal motor latency increased by $0.2msec/^{\circ}C$ drop in temperature between $25^{\circ}C$and $35^{\circ}C$ in the median, ulnar and peroneal nerves. The temperature affect the neuromuscular transmission; The miniature endplate potential (MEPP) and endplate potential (EPP) are increase with increasing temperature. In myasthenia gravis, the reduction in the decremental response is observed following cooling. The lowering temperature make increase the amplitude of sensory compound action potential; make enlarge the surface area of compound muscle action potential with very little increase in amplitude; make diminish the fibrillation potential and increase the myotonia in needle electromyography (EMG). Because of these findings mentioned above, the skin temperature should be routinely monitored and controlled during nerve conduction tests and needle EMG and should be taken into account when interpreting the findings.

• The Journal of the Korea Contents Association
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• v.9 no.12
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• pp.1-9
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• 2009

A doll created by various materials is a miniature based on human model, and it has been one of components in a puppet show to take some responsibility for human's culture activity. However, demand and supply keeps on the decrease in the puppet show industry, since professional puppeteer has been reduced rapidly, and also it is difficult to initiate into the skill. Therefore, many studies related Robotic Marionette for automation of puppet show have been internationally accompanied, and more efficient structure design and process development are required for better movement and express of puppet with motor based controller. In this research, we suggest the effective way to enable to express the marionette's motion using motion data based on motion capture and 3D graphic program, and through applying of 3D motion data and proposal of simulation process, it will be useful to save time and expenses when the Robotic Marionette System is practically built.