• 연구논문집
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• 통권32호
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• pp.15-22
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• 2002

In offset or intaglio printing machine, it's operated with combination of blanket cylinder and impression cylinder. The blanket cylinder has some number of grooves to attach the blanket on surface. In case of operating the printing machine, it has generate mechanical impact noise when the two cylinders encounter with the grooves. So, in this study, we developed a printing pressure control algorithm with hydraulic servo control system. We also proposed simulation model of experimental device to analysis the throw on force response of hydraulic servo actuator. Finally, we have reduced the mechanical impact noise and improved printing quality with a groove detecting signal and PI control of hydraulic servo actuator.

• 동력기계공학회지
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• 제20권6호
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• pp.34-39
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• 2016

This paper is the numerical study on the correlation of leakage by the variation of inlet pressure and clearance in hydrostatic bearing. The main goal of this study is to apply to the design of hydro system the results that the pocket pressure and the leakage rate according to the inlet pressure and the clearance between piston and cylinder tube. Because the hydrostatic bearing in hydraulic cylinder has the narrow rectangular channel between piston and cylinder tube, so to verify the numerical scheme, it has been compared with the experimental results of Brackbill and Kandlikar. The pressure data of numerical results inside narrow rectangular channel correlate was showed a good agreement with experimental results, thereby the numerical scheme was applied to the real model that is a hydraulic cylinder with the hydrostatic bearing. In conclusion, the pressure differences between inlet and pocket were shown within 3%. Leakage rates were showed rapidly increased pattern between about 4.5 and 6.7 times because the section area to calculate the leakage rates were proportioned to a square of diameter. The correlation equation was calculated among the inlet pressure, the clearance and the leakage rate by using the linear regression.

• 유공압시스템학회논문집
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• 제4권2호
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• pp.21-27
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• 2007

This paper deals with the issue of trajectory tracking control of a clamping cylinder for injection moulding machine, which is directly driven by speed controlled hydraulic pump in combination with AC servomotor. As a fundamental step prior to tracking controller design, feedback control system is developed by implementing a position control loop parallel with a system pressure control loop. A sliding mode controller combining velocity feedforward scheme is developed for enhancing the tracking performance. Consequently a significant reduction in tracking error is achieved for both position and pressure control applications.

• 드라이브 ㆍ 컨트롤
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• 제20권1호
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• pp.27-33
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• 2023

From the perspective of dental chair manufacturers, it is important to of localizing hydraulic system in order to secure market competitiveness. This study aims to develop the analysis model of a dental chair which overseas companies secure core technologies. The study follows the steps below. First, the component parts of the solenoid valve unit of a foreign leading company are analyzed and implemented in virtual environment. Second, dynamic behavior scenario is established based on solenoid valve signal chart provided by a foreign leading company. The analysis model is verified and its performance is analyzed using dynamic behavior according to each scenario. Third, a simulation is carried out to determine whether the cylinder velocity of designed hydraulic system surpasses 1cm/s as required by the design.

• 한국산업융합학회 논문집
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• 제26권1호
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• pp.175-181
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• 2023

In offshore plants, various equipments including cranes and davits are used for safety management. Hydraulic cylinder type actuators are mainly used for luffing operations such as cranes and davits. However, in the case of a cylinder using hydraulic pressure, a separate power pack is required to supply hydraulic pressure. When used for a long time, maintenance costs such as sticking of hydraulic valves, contamination of hydraulic oil and deterioration of hydraulic hoses occur. In addition, a lot of hydraulic oil is used in the handling of cranes and davits, which causes marine pollution due to management problems. As a result, as interest in marine pollution prevention has increased recently, interest in actuators that do not use hydraulic pressure is also increasing. Therefore, in this study, we intend to develop a davit with an electric cylinder type actuator that uses electricity rather than hydraulic pressure by the SOLAS regulation. In other words, the conceptual design of the davit driven through the linear motion of the ball screw using electricity is performed, and the structural safety of the drive is also reviewed so that it can be utilized in the industrial field.

• 한국해양공학회지
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• 제29권2호
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• pp.120-127
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• 2015

When a deep-seabed lifting pump is kept this device has bending and deformation in the axis due to its long length(8m). These influences can be caused a breakdown. Therefore, a mounting must be developed to keep the lifting pump safe. This paper discusses the hydraulic cylinder design of the lifting pump and structural safety estimation of the mounting using SBD(simulation-based design). The multi-body dynamic simulation method is used, which has been used in the automotive, structural, ship building, and robotics industries. In this study, the position and diameter of the hydraulic cylinder were determined based on the results of the strokes and buckling loads for the design positions of the hydraulic cylinder. A structural dynamic model of the mounting system was constructed using the determined design values, and the structural safety was evaluated using this dynamic model. According to these results, this system has a sufficient safety factor to manufacture.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.917-922
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• 2008

In order to reduce energy consumption, secondary controlled system has been applied to many types of equipments. In lifting equipments or press machines using hydraulic cylinder, a hydraulic transformer is used as a control component instead of a valve for motion control and a component for recovering potential energy of load. The transformer is combination of a variable displacement pump/motor as a secondary controlled element and a fixed displacement pump/motor. Based on the nominal model derived from mathematical model, the feedback type two-degree-of-freedom controller is designed and implemented. From simulation results, the disturbances including nonlinear friction torque, leakage flow and load force can be compensated and good positioning accuracy is obtained. It show that the proposed controller is effective.

• 대한기계학회논문집A
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• 제28권7호
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• pp.955-960
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• 2004

In this paper, a neural network controller that can be implemented in parallel with a PD controller is suggested for motion control of a hydraulic servo cylinder. By applying a self-excited oscillation method, the system design parameters of open loop transfer function of servo cylinder system are identified. Based on system design parameters, the PD gains are determined for the desired closed loop characteristics. The Neural Network is incorporated with PD control in order to compensate the inherent nonlinearities of hydraulic servo system. As an application example, a motion control using PD-NN has been performed and proved its superior performance by comparing with that of a PD control.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2015년도 추계학술대회
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• pp.910-912
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• 2015

본 논문에서는 중장비나 댐의 수문 등의 적용된 유압 실린더의 변위(stroke)를 검출하여 유압 실린더의 정밀제어 또는 자동화를 위한 정전용량 센서(Capacitive Sensor) 및 변위 검출 시스템을 설계하였다. 기존 실린더의 변위 검출 방식인 코일을 이용한 자기장 센서, LVDT 센서 등은 높은 정확도에 비해 충격 및 진동 완화 또는 센서 보호 하우징(Housing) 등 부수적인 설비에 따른 높은 비용, 큰 부피와 같은 문제가 있다. 따라서 이러한 개선하기 위해 유압 실린더 내의 직접 적용되어 실린더의 변위 검출이 가능한 정전용량 센서를 설계하였으며, 설계한 정전용량 센서를 통하여 실린더의 변위에 따른 커패시턴스 값을 검출하여 실린더 위치 측정이 가능한 시스템을 설계 및 검증 하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집A
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• pp.426-432
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• 2000

The hydraulic loading system real-time simulator using a PC and I/O interface board is developed to simulate the dynamic characteristics of hydraulic loading system in real time. The simulator receives the digital on-off control signals generated by the operator through the D/I channels, updates the state and output variables of the hydraulic loading system responding to the input signals and draw the moving pictuters of the lift cylinder, lift arm and loading box on the PC monitor in real time. Also, the operator can observe the displacement and pressure of cylinder, the rotatinal angle, reaction force, and safety factors of lift arm representing the operation of hydraulic loading system through the PC monitor in real time. The real-time simulator can be a very useful tool to design industrial dynamic systems and feel the goodness of the system operation since the operator can observe the moving pictures of the operating system in real time as he operates the real time simulator.