• 드라이브 ㆍ 컨트롤
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• 제16권4호
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• pp.87-92
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• 2019

Rotary dampers are damping devices which provide high resistance to shaft rotation. Rotary dampers are being used in various areas to enable the gentle opening and closing of the rotation motion relative to home furniture, industry machinery and automotive parts. Rotary dampers can be installed directly at the rotating point of a various part and can achieve uniform, gentle movement which increases quality and value of products. And generally, the silicone fluid is used as the damping medium because of its stable viscous properties. The movement of these little decelerators can be achieved with a high viscosity of working fluid and throttles installed in the body of the rotary damper. The damping force can be achieved clockwise, anti-clockwise or in both directions according to the structure of the orifices or throttles. In this paper, the torque performances of the rotary damper containing air in the working fluid were studied. For this purpose, the torque characteristic of the rotary damper according to the variation of various operating conditions such as clearance of leakage, dimensions of groove orifice, content ratio of air, etc., were simulated with AMEsim software.

• 유공압시스템학회논문집
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• 제8권3호
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• pp.1-7
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• 2011

As the technologies of electronic device have advanced these days, most of mechanical systems are designed with electronic control unit to take advantage of control parameter adaption to operating conditions and firmware flexibilities as well. On-board diagnosis, which detects the system malfunction and identifies potential source of error with its own diagnostic criteria, and fail-safe that can switch the mode of operation in view of recognized error characteristics enables easy maintenance and troubleshooting as well as system protection. This paper dealt with the development of diagnosis and fail-safe function for proportional flow control valve. All type of errors related to valve control system components are investigated and assigned to a specific hexadecimal codes. Cumulative error detection algorithm is applied in order for the sensitivity and reliability to be appropriate. Embedded simulator which runs simultaneously with system program provides the virtual error simulation environment for expeditious development of error detection algorithm. The diagnosis function was verified both with solenoid valve and embedded simulator test and it will enhance the valve control system monitoring function.

• 드라이브 ㆍ 컨트롤
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• 제10권2호
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• pp.13-22
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• 2013

It is difficult to analytically derive a volumetric displacement formula of gerotor hydraulic pump/motor because geometric shape of rotors is complicated. An analytical method about the volumetric displacement is proposed in this work, which is relatively easy and based upon two physical concepts. The first one is energy conservation between hydraulic energy of the pump/motor and mechanical input/output energy. The second concept is torque equilibrium with respect to inner and outer rotors. The formula about the volumetric displacement is derived for the common case of inner and outer rotors rotate with respect to fixed axes. The formula is verified by comparing another analytical displacement formula, and it is numerically verified by comparing numerical results, which is calculated for geometric specification of a motor. The numerical displacement is calculated through CAD software program and MATLAB program. The proposed analytical formula can be utilized in analysis and design of hydraulic gerotor motors.

• 드라이브 ㆍ 컨트롤
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• 제14권3호
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• pp.8-17
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• 2017

With automobiles sharply increasing in numbers worldwide, we are faced with critical social issues such as traffic accidents, traffic jams, environmental pollution, and economic inefficiency. In response, research on ITS is promoted mainly by regions with advanced automotive industry such as the U.S., Europe, and Japan. While Korea is working on moving forward in the global market through developing and turning to global standards systems related to ASV (Advanced Safety Vehicle), the country is not fully prepared for such projects. The purpose of ACC (Adaptive Cruise Control) is to control a vehicle's longitudinal speed and distance and minimize driver workload. Such a system should be valuable in preventing accidents, as it reduces driver workload in the 21st-century world of telematics created by development of the automobile culture industry. In this light, the thesis presents a method to test and evaluate ACC system and a mathematical method to assess distance. For the proposed test and evaluation, theoretical values are tested with vehicle test and a database is acquired, by using vehicles equipped with an ACC system. Theoretical evaluation criteria for developing ACC system may be used and scenario-specific evaluation methods may find useful application through testing the formula proposed by comparing the database and mathematical method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.557-558
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• 2007

변화, 발전하는 IT기술과 디지털 기술, 그리고 네트워킹 기술 등에 따라 변전소의 운용 및 자동화 부문에 있어서도 적지 않은 변화가 일어나고 있다. 변전소의 건설 및 운용 면에 있어서도 예외가 아니며, 관련된 관심 사항으로는 시스템 구축 및 운용 시의 경제적인 측면, 시스템의 신뢰성, 그리고 유지보수 및 설비 관리의 효율성 등을 언급할 수 있다. 최근의 기술 추세는 Ethernet 통신 기반의 Network Device를 근간으로 하는 시스템으로의 변신을 주장하고 있으며, 세계 유수의 전력 설비 Maker에서도 이에 부응하기 위한 Network Device를 개발, 출시하고 있는 실정이다. 당소에서도 이와 같은 기술 추세에 부응하여 소위 미래형 변전소에서 요구되는 각종 ND의 개발을 추진하고 있으며, 그 첫번째 결과물로 154kV GIS의 운용 시에 요구되는 각종 제어 및 감시를 위한 Digital Control Unit(이하 DCU)을 개발하였다. 두 번째로 이와 같은 DCU와 연계하여 기존의 Remote Control 기능을 구비하고 상위시스템과 연결되며 변전실내에서 운용되는 Remote Control Unit(이하 RCU)을 개발하였다. 마지막으로 예방진단 시스템과 관련하여 주요 전력 설비의 상태 정보를 취합하는 Serial 통신 기반의 Static Type의 Diagnostic Analysis Unit(이하 DAU)을 하나의 Network Device로 개발함으로써 감시, 진단, 제어 등의 요구기능이 일체화 된 네트워크 기반의 미래형 변전소 자동화 시스템 구축에 한걸음 다가가는 기반을 마련하였다.

• 드라이브 ㆍ 컨트롤
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• 제14권4호
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• pp.45-50
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• 2017

The gas spring is a hydropneumatic adjusting element, consisting of a pressure tube, a piston rod, a piston and a connection fitting. The gas spring is filled with compressed nitrogen within the cylinder. The filling pressure acts on both sides of the piston and because of area difference it produces an extension force. Therefore, a gas spring is similar in function compare to mechanical coil spring. Conversely, optimization is a process of finding the best set of parameters to reach a goal while not violating certain constraints. The AMESim software provides NLPQL (Nonlinear Programming by Quadratic Lagrangian) and GA (genetic algorithm) for optimization. The NLPQL method builds a quadratic approximation to the Lagrange function and linear approximations to all output constraints at each iteration, starting with the identity matrix for the Hessian of the Lagrangian, and gradually updating it using the BFGS method. On each iteration, a quadratic programming problem is solved to find an improved design until the final convergence to the optimum design. In this study, we conducted optimization design of the gas spring reaction force with NLPQL.

• 드라이브 ㆍ 컨트롤
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• 제15권4호
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• pp.74-80
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• 2018

A damper is a hydraulic device designed to absorb or eliminate shock impulses which is acting on the sprung mass of vehicle. It converting the kinetic energy of the shock into another form of energy, typically heat. In a vehicle, a damper reduce vibration of car, leading to improved ride comfort and running stability. Therefore, a damper is one of the most important components in a vehicle suspension system. Conventionally, the design process of vehicle suspensions has been based on trial and error approaches, where designers iteratively change the values of the design variables and reanalyze the system until acceptable design criteria are achieved. Therefore, the ability to tune a damper properly without trial and error is of great interest in suspension system design to reduce time and effort. For this reason, a many previous researches have been done on modeling and simulation of the damper. In this paper, we have conducted optimal design process to find optimal design parameters of damping force which minimize a acceleration of sprung mass for a given suspension system using genetic algorithm.

• 드라이브 ㆍ 컨트롤
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• 제18권4호
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• pp.28-34
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• 2021

Among the currently available types of fuel, LNG emits a relatively small amount of nitrogen oxide and carbon dioxide when it burns in the engine. However, since LNG is a flammable material, leakage during bunkering can lead to accidents, such as fires. Therefore, it is necessary to install a remote operation emergency shut-down (ESD) valve to block the flow and leakage of LNG in an emergency situation that occurs during bunkering. The ESD valve uses a hydraulic driving device consisting of a hydraulic control valve and a hydraulic motor to control globe valve disc displacement, which regulates the flow path for LNG transfer. At this time, there are various nonlinearities in hydraulic driving devices; hence, it is necessary to design a controller with robust control performance against these uncertainties. In this study, modeling of the ESD valve was carried out, and a sliding mode controller to control the displacement of the globe valve disc was designed. As a result, it was confirmed that the designed control performance could be achieved by overcoming nonlinearity characteristics using the designed controller.

• 한국ITS학회 논문지
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• 제22권2호
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• pp.93-104
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• 2023

도로법에 의거한 도로교통량 상시조사는 매설식 AVC를 통해 12종 차종분류가 이루어지고 있다. 하지만 매설식 AVC 장비는 차량과의 마찰, 도로 균열, 소성변형, 도로공사로 인한 센서의 물리적 파손 등으로 인해 장비 가동률이 낮고, 수집 정보의 정확도와 신뢰도 저하 문제가 발생하고 있다. 이로인해 장비보수 등 유지비용 또한 증가하고 있다. 이러한 문제를 해결하고자 비매설식 AVC 장비 도입을 위한 연구가 진행되고 있으나, 차종을 분류하기 위해 복수의 장비 또는 교통량 정보 매칭을 위한 별도의 DB 구축·운영이 필요하였다. 이에 본 연구에서는 자동차 관리법에 근거하여 운영 중인 자동차관리정보시스템(VMIS)의 차량 제원 정보와 번호판 자동인식 기술(ANPR)을 활용한 12종 차종분류 방안을 마련하고자 하였다. 이를 통해 기존 도로교통량 조사체계를 개선하고 자동차 제원 정보를 활용하여 친환경 차량 분류 등 도로교통량 통계 고도화, 다변화에 기여할 수 있을 것으로 기대된다.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2008년도 정기학술발표대회 논문집
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• pp.364-367
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• 2008

현재 건설 산업에서 나타나고 있는 숙련공 부족 현상, 기술자의 고령화 문제, 안전상의 문제 등을 해결하기 위한 대안으로 자동화 건설기계들의 개발 요구가 점점 높아지고 있다. 특히 토공작업은 매우 기계 의존적인 작업이기 때문에 자동화된 굴삭기 개발과 관련된 연구가 많이 이루어지고 있다. 자동화 굴삭 시스템을 개발하는 데 있어서는 안전을 확보하는 것이 중요하다. 그래서 본 연구의 주제는 자동화 굴삭 시스템의 안전성을 어떻게 향상시키는 기술을 개발하는 데에 있다. 또한 본 연구의 목적은 굴삭 작업에 있어서 자동화 굴삭기의 객체 탐지를 위한 알고리즘을 개발하여 소프트웨어에 적용하는 것이다. 선행연구를 통해 여러 가지 센싱 기술들의 성능에 대해 조사 및 분석을 실시하였으며, 최적의 레이저 센서를 선정하여 성능의 적정성을 입증하기 위한 실험을 실시하였다. 사용자 인터페이스 프로그램을 위한 객체탐지 알고리즘을 개발하였고, 이는 자동화 굴삭 시스템의 안전관리 시스템 개발의 원천기술로써 활용될 수 있을 것이다.