• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.876-880
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• 2000

Vibration problem of deckhouse structure in a container vessel was investigated through the analysis and measurement. The natural frequency of deckhouse structure was found to be resonant with main engine 4th order excitations in the operating range, major sources of which were main engine inertial moment and axial thrust of the propulsion shafting system. To investigate and solve the problem, exciter test was performed to identify the vibration chracteristics of the ship structure and mechanical balancer was installed to compensate the 4th order inertial moment. Measurement results under the conditions with and without balancer operating were compared and analyzed to confirm the balancer effect. Good coincidence was found between the measurement and analysis results, which made it possible to predict the vibration problem in the earlier design stage.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1695-1696
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• 2008

KRRI (Korea Railroad Research Institute) is developing a bimodal tram since the 2003s. The vehicle will be used in the public transportation system. The bimodal tram has the advantages of both bus and train. Bus system has the advantages of flexibility of the routes delivering passengers to the destination and easy accessibility. Train is to meet the scheduled arrival and massive public transportations. The vehicle is the rubber tired tram and is all wheel steered single articulation. The propulsion system is configured by CNG hybrid system. The length of the vehicle is 18m. The vehicle lanes will be marked with permanent magnets that are buried in the road. The vehicle can be automatically operated by navigation control system (NCS). In this paper, we introduce the driving system of the bimodal tram which is developed by KRRI.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1036-1037
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• 2015

지상1차 선형동기전동기는 속도와 위치센서가 회전축에 설 부착되어져 있는 회전형 동기전동기와 달리 가이드웨이를 따라 위치센서 관련부품이 설치되어져 있다. 차상 자기부상열차로부터 전송되는 위치신호는 지상 추진인버터의 실시간 추진제어에 필요한 정보에 미흡하다. 본 논문에서는 지상1차 선형동기전동기를 구동하는 추진인버터에 대한 위치신호 추정기에 대하여 제시하였다. 지상 추진인버터가 요구하는 수준의 높은 분해능의 위치신호를 얻기위하여 직류모터 모델의 블록선도로부터 폐루프 위치관측기를 설계하고 시뮬레이션 및 실험을 통해 가용 성능 확인하였다.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1075-1080
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• 2008

An engine for marine propulsion and power generation consists of several cylinder liner-piston sets. And the oil groove is on the cylinder liner inside wall for the lubrication between a piston and cylinder. The machining process of oil groove has been carried by manual work so far, because of the diversity of the shape. Recently, we developed an automatic grinding robot system for oil groove machining of engine cylinder liners. It can covers various types of oil grooves and adjust its position by itself. The grinding robot system consists of a robot, a machining tool head, sensors and a control system. The robot automatically recognizes the cylinder liner's inside configuration by using a laser displacement sensor and a vision sensor after the cylinder liner is placed on a set-up equipment.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.10
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• pp.770-778
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• 2013

Solar sail propulsion uses solar radiation pressure to propel spacecraft without propellant, and it is useful for deep-space missions and continuos orbit maneuver missions. After a brief introduction of solar sail dynamics, locally optimal trajectories in Sun-centered and Earth-centered orbits are analyzed. Numerical simulations for the optimal trajectories are performed. Trajectory for the rendezvous with Halley comet is generated, and different planet escape methods are compared.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.876-879
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• 2003

본 논문은 전동차용 추진제어장치의 재점착제어에 관한 것이다. 본 연구에서는 공전검지 방법에 대하여 기술하고, 등가 관성량을 이용한 추정재점착제어에 관하여 제시한다. 서울시 6호선 국산화 전동차(609편성)와 광주도시철도 1호선 전동차에 적용하여 재점착 제어성의 우수함과 안정성을 검증 하고자 한다.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.886-890
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• 2003

This paper introduces the combined test results of the traction system for KHST(Korean High Speed Train: hereafter refer to KHST). The main purpose of this combined test is to verify the performance of the traction system that is designed to operate up to maximum 350km/h speed. Combined test system consists of a traction transformer, two AC-DC PWM converters, a PWM Inverter, two traction motors and flywheel system. Flywheel system represents equivalent model of the train inertia. Also traction control system and MASCON Interfaces are included. Various kinds of experiments are performed to prove total traction system performance and detail waveforms are described

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.295-296
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• 2010

본 논문에서는 고속전철용 추진제어장치의 개발 및 본선 주행시험에 관한 내용을 소개하였다. 고속열차용 추진제어장치는 입력 전류의 고조파를 감소하기 위하여 단상 PWM 컨버터 2대가 병렬로 구성되고 인버터는 3상 인버터 1대로 구성된다. 추진제어장치의 전력회로를 간단히 구성하기 위하여 최대용량(4500V/4200A)의 IGBT 전력소자를 적용하였다. 3상 인버터는 가속시 스위칭 기어현상을 저감하기 위하여 저주파 동기 PWM 기법을 적용하였다. 추진제어장치의 성능을 평가하기 위하여 실제 차량이 운행될 본선에서 속도 300km/h까지 가속시험, 비상제동 시험, 구배기동 시험 등을 실시하였다. 시험을 통하여 제작된 추진제어장치가 성능사양을 만족함을 확인하였다.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.21 no.1
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• pp.30-38
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• 2013

This paper describes the design optimization of Unmanned Aerial Vehicles(UAVs). An optimization framework has been developed and implemented for the conceptual design of UAVs. An integrated design analysis program was developed with several analysis modules such as propulsion, performance, mission, weight, and stability and control. A UAV configuration design optimization was performed by implementing the integrated analysis to enhance the endurance of UAVs. A SQP optimizer was utilized to build an optimization module for this program and sensitivity analysis was performed to determine the trends of shape variables for developing optimization objective. In conclusion, the results indicate that the resulting optimized UAVs configurations show performance improvements over the baseline design and reliable analysis results.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.15 no.3
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• pp.33-45
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• 2007

The collision avoidance maneuver flight simulation for tilt rotor unmanned aerial vehicle was performed by time-accurate numerical integration method based on wind tunnel test data. Five representative collision avoidance maneuvers were simulated under constraints of aerodynamic stall, propulsion power, structural load, and control actuator capability. The collision avoidance performances of the maneuvers were compared by the computed collision avoidance times. The sensitivities of initial flight speed and collision zone shape on the collision avoidance time were investigated. From these results, it was found that the moderate pull-up turn maneuver defined using moderate pitch and maximum roll controls within simulation constraints is the most robust and efficient collision avoidance maneuver under the various flight speeds and collision object shapes in the tilt rotor UAV applications.