• Aerospace Engineering and Technology
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• v.7 no.1
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• pp.49-60
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• 2008

In this technical paper, summarization of developmental results for the tilt-rotor SUAV Drive System being developed in the Smart UAV Development Center is carried out in view of design and analysis for the major components. The Drive System driving for the Rotor System of the SUAV is composed of very precise and advanced equipments, and also the applied technologies for development of the system had not ever experienced in the Korea. Therefore the collaboration study with an advanced company (EATI) in the USA performed in order to develop the SUAV Drive System.

• Proceedings of the IEEK Conference
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• 2003.07c
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• pp.2811-2814
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• 2003

본 논문에서는 Sub-nano 수준의 위치정밀도와 분해능을 갖는 Piezo actuator 의 제어기 설계를 목적으로 하였다. 이산 시간 상태 공간에서의 Piezo actuator를 이용한 1 축 스테이지 드라이브 시스템 SISO 제어기를 설계하였다. Piezo actuator 의 소재 자체의 특성으로는 Hysteresis 가 있으며, 이는 정상상태에서 Piezo actuator 의 위치 오차를 발생하는 주요 원인이 된다. 제어기의 설계는 극점 배치 방법을 기본으로 하여 Hysteresis 에 대한 보상을 목적으로 적분제어방식과 외란 추정기를 각각 적용하였다. 모의실험을 통하여 제어기의 설계 및 시뮬레이션 하였으며, Hysteresis 에 대한 보상이 이루어짐을 보았고, 실험을 통하여 이를 증명하였다.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.10a
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• pp.109-114
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• 1997

차세대 원전 1주기 노심에 대해 MSHIM기법을 적용하여 100-50-100% 출력, 14-2-6-2시간 형태의 일일부하추종운전시 노심 거동을 ONED94 전산코드를 통해 모사하였다. 계산결과 1300MWe급 차세대 원전에서 단순한 제어봉 구동논리를 통해 부하추종운전중의 잉여반응도와 축방향 출력분포를 적절히 제어할 수 있었으며, 붕산수 조절없이 안전한계 범위 내에서 일일부하추종운전이 가능하였다. 또한 MSHIM기법을 위한 차세대원전의 제어봉 배치를 변경 제시하였다.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.3
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• pp.211-216
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• 2015

Large hydraulic excavator weighted 90 tons used the several pumps installed in parallel to use the hydraulic pump driving gearbox to improve fuel consumption by improving the energy efficiency of the hydraulic system. Gearbox connected to hydraulic pump supply the mechanical output to the high pressure and low pressure pump to be supplied by torque and rotation, which are the mechanical power, through a input shaft connected to large size engine of the excavator. So, gearbox connected to hydraulic pump is same as main artery in the human body and is required long life because it operates the hydraulic pump continuously during operating the engine. This study had used oil contamination analysis method to check the wear characteristics of the gearbox and frequency response characteristic analysis method to check the failure of the teeth failures of gearbox, while the test equipment adopted by the electrical feedback method to reduce the energy consumption was operating for the life assessment, in which the required power was 600 kW input power.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.1
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• pp.1-8
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• 2016

In this study, we propose a control algorithm for Inertially Stabilized Platforms (ISP), which combines Disturbance Observer (DOB) with conventional proportional integral derivative (PID) control algorithm. A single axis ISP system was constructed using a direct drive motor. The joint friction was modeled as a nonlinear function of joint speed while the accuracy of the model was verified through experiments and simulation. In addition, various Q-filters, which have different orders and relative degrees of freedom (DOF), were implemented. The stability and performance of the ISP were compared through experimental study. The performance of the proposed PID-plus-DOB algorithm was compared with the experimental results of the conventional double loop PID control under artificial vehicle motion provided motion simulator with six DOF.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.227-231
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• 2004

Technological advance in information technology has sparked the necessity of small form factor (SFF) optical disk for mobile devices. Small form factor optical disk is highly anticipated to be a next generation storage device because it can be used for a cost-effective way compared with solid state memory. For the application to the 5 mm height small-form-factor optical disk drive, we have presented an optical flying head and swing arm actuator. In this study, we propose a small 1-axis actuator for compensating ficus error and SA due to the variation of cover-layer thickness in the cover-layered small optical disk. The main design issues of the 1-axis actuator are the realization of compact structure and the new support structure of the actuator: Finally, the compensating principle and performance of the 1-axis actuator will be explained.

• Journal of the Korean Society of Propulsion Engineers
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• v.5 no.2
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• pp.44-50
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• 2001

After modeling an aircraft turboprop engine using SIMULINK$\circledR$, performance simulation of PT6A-62 engine, which is main power plant of KT-1, was performed. For validation, performance parameters of the SIMULIINK model were compared with the simulated results by GASTURB program. It was confirm that the results by the SIMULINK model were well agreed with those by GASTURB within 1.07%, It was assumed that installation losses were bleed-air exteraction with a range from 0% to 5%, and power for accessories with a range from 0 to 20hp. In this investigation, it was found that the shafthorsepower was decreased by maxium 0.68%, but specific fuel consumption ratio was not effected nearly by these losses.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.1
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• pp.8-14
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• 2013

This paper intends to provide the whirling characteristics of an asymmetric rotor-shaft system with a non-ideal DC motor. The equations of motion have been derived in terms of system parameters such as the internal/external damping, the asymmetry and the motor voltage. By imposing the conditions that the motor input power should be balanced by the dissipated power, steadystate whirling characteristics are obtained such as the whirling amplitude, the whirling frequency and the stability diagrams. Results show that the whirling stability is affected by the internal/external damping and the asymmetry as well as the motor voltage. Also, the whirling amplitude at the steadystate is increased and the motor speed is lowered as the internal damping becomes higher or the external damping is reduced. In addition, the asymmetry causes the variation of the whirling orbit, which becomes splitted into two distinct trajectories. Finally, non-ideal characteristics of the DC motor is found to reduce the whirling motion in case of steadystate whirling with high asymmetry and high internal damping.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.1
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• pp.48-56
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• 2008

Nowadays, CMG(Control Moment Gyros) becomes one of the essential actuators for satellite attitude control. The method to define the key requirements of CMG is suggested to avoid CMG's singularity problem for the limited envelope of angular momentum of 2H. Furthermore, the analysis and simulation are carried out to provide a necessary guideline when three CMGs are used for spacecraft control purpose. An improved configuration of redundant four CMG cluster, slightly different from the conventional configuration, is proposed not only to avoid the CMG singularity problem, but to improve agility about roll or pitch-axis.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.1
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• pp.151-159
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• 2003

The front 2 pieces of the 3-piece steel propeller shaft installed on a 8.5-ton truck were redesigned with a 1 -piece composite propeller shaft with steel yokes and spline parts to get the reduction of weight and the improvement of NVH characteristics. Based on the analysis of bending vibration, strength and cure-induced residual stresses of the composite propeller shaft, proper composite materials and stacking sequences were selected. The composite propeller shaft requires a reliable joining method between the shaft and steel end parts through a steel connector. From 3-D contact stress analyses of the laminated composite shaft with bolted Joints, the 3-row mechanical joint which satisfies the torque transmission capability has been designed. Several full-scale composite shafts were fabricated and tested to verify the design analyses. The design requirements are shown to be satisfied. With the newly designed composite shaft, the weight reduction more than 50% and improvements in NVH characteristics have been achieved.