• Journal of the Korean Society for Railway
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• v.10 no.6
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• pp.709-716
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• 2007

An active steering bogie has been theoretically proved to improve both stability and steering performance remarkably. However, It has not been commercialized yet even though many researchers have been trying to develop it because some technical difficulties still exist such as information acquisition fer active control, increasing mechanical components, high energy consumption, fail-safe problem and so on. To solve those problems, an advanced active steering mechanism is proposed in this paper. With this mechanism, required control force is small enough to use direct drives. Therefore, the number of additional mechanical components can be minimized since mechanical transducers like gears are not necessary. Fail-safe function can be also inserted easily. In this paper, concept design of the proposed active steering bogie is introduced and the possibility is verified through computer simulation using linear dynamic model.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.2
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• pp.638-645
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• 2014

This paper presents results of a study for development and application of container massive transportation system. The system is aimed to improve competing power of Korean container ports. This paper selects Double stack Multi-Trailer System (DMTS) under consideration of pros-con analysis between three systems alternatives as well as operation process of existing Korean container terminal companies. An analysis of turning radius is undertaken for applying the system. Key elementary technologies was derived by patent analysis. DMTS has no problems in utilization to existing Korean container ports. Further, the system is expected to highly potential to improve operational efficiency in the container ports thanks to its high unit transportation capacity.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.817-818
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• 2009

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.6 s.249
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• pp.684-690
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• 2006

This study proposes and validates a new column type electric power steering system (EPS-TT). It is driven by a uni-directional motor and two electro-magnetic clutches. The assist motor produces assist torque in only one direction and two clutches transmit the torque to the column of steering system in either left or right direction with respect to the steering input. A full order and a reduced order models are developed to evaluate the EPS-TT. Models are also used to investigate the vehicle responses. A PID control logic is designed to control the torque of the assist motor. A driver model is applied to the system and the resulting performances are analyzed. The results show that the performances of the full order model are similar to those of reduced order model. The results also prove that the performances achieved by the EPS-TT are improved compared to those of a conventional EPS-TT across the frequency domain.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.12
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• pp.2883-2890
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• 2000

In this study, a Hardware-In-The-Loop-Simulation(HILS) system for developing a Electric-Power-Steering(EPS) system is designed. To test a EPS by HILS system, a mathematical vehicle model with a steering system model has been constructed. This mathematical model has been constructed. This mathematical model has been downloaded to the Digital-Signal-Processor(DSP) board. To realize the lateral force acting on the front wheel in a real car. the steering wheel angle sensor and vehicle velocity have been used for input signal. The force sensor has been used for a feedback signal. The full vehicle states could by simulated by the HILS system. Consequently, the HILS system could by used to analyze control-parameters of a EPS that contributes to the maneuverability and stability of a vehicle. At the same time, the HILS system can evaluate the whole performance of the vehicle-steering system. Also the HILS system could do test could not be executed in real vehicle. The HILs system will useful for developing the control logic for the EPS system.

• Journal of Drive and Control
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• v.17 no.4
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• pp.113-124
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• 2020

Most of the work of construction equipment and agricultural machinery is done in off-road conditions. Autonomous driving required in these conditions uses GPS sensors, and PID controllers to control their speed and position. The hydrostatic steering, which is composed of a PSU, hydraulic hoses, and cylinders, rather than a mechanical coupling is used in these equipments. The PSU plays a key role in hydrostatic steering. Precise control of the position under various conditions requires detailed behavioral analysis of the basic components and operation. Two Gerotor PSU is now a commonly used safer option. The components of the PSU can be divided into mechanical and hydraulic actuating elements by its behavior. Since the system is combined by mechanical and hydraulic elements, the modelings are performed using Amesim, which is one of the most effective for the multi-domain dynamic system analysis. To confirm the validity of the model, input torque and pressures are checked with varying steering speed. The opening and the steering speed of normal and newly designed control valve set is investigated with the effect of centering spring force and friction. Finally, simulation results with fully detailed model with two gerotors are analyzed and compared with simple model.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.337-338
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• 2008

2008년 현재 우리나라는 10%의 인구가 60세 이상인 이른바 고령사회에 접어들었다. 노인 인구의 증가로 인해 노인이 여가생활 또는 일반생활을 보조하기 위한 보행 보조기에 대한 관심이 증가되고 있다. 대부분 동력이 없는 보행보조기를 사용하고 있으며 이러한 기구는 경사로 공간 또는 힘이 약한 노인들에게 취약성을 가지고 있다. 이에 동력형 보행보조로봇에 관심이 증가하고 있다. 동력형 보행보조로봇 역시 경사로에 있어서 편리성과 안전성을 높이기 위한 연구가 필요한 실정이다. 이에 본 논문에서는 보행보조로봇이 경사로에 진입 하였을 경우 기울어진 경사로의 정도를 인식하여 모터를 제어 한다. TILT 센서를 이용하여 기울이짐 정도를 측정 하였고, 또한 로봇의 전류 실시간으로 체크하여 로봇의 안전성을 향상 하였다. 제어 시스템 구성은 사용자의 보행의지를 파악하기위해 FSR 센서를 부착하여 조향장치로 사용하였으며, 경사로를 인식하기 위해 Liquid 타입의 TILT 센서를 사용하였으며, 모션 제어를 위해 DSP를 사용하였다. 본 제어 시스템을 보조보행로봇에 적용하였을 때, 보행보조로봇이 오르막 경사로에 진입시 기존보다 힘을 적게 사용하여 경사로를 진행하였으며, 경사로에서 브레이크 작동속도가 향상 되었다. 또한 내리막 경사로에서는 모터의 힘을 적게 사용하고 중력의 힘을 사용하여 이를 통해 전류의 소비량을 개선 하였다.

• Journal of Power System Engineering
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• v.3 no.3
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• pp.70-75
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• 1999

This study is for the development of tie rod end, a parts of steering system, that would be changed with plastic material. The position of weld line is founded by the analysis of Mold Flow, computer software with FEM(Finite Element Method). Then new mold is designed by consideration with the locations of weld line. PA66(G/F 35%), PA6(G/F 45%), PET(G/F 45%) and PET(G/F 55%) are tested two types loading conditions for selecting suitable material, the requirement tensile load(more 19600N). PA6(G/F 45%) showed high mechanical properties in this study. And then, tensile strength was compared between conventional metal products and the injection molded products which were reinforced with 33%, 34%, 45%. 60% of glass fiber in matrix material. In the case of, the measured two types of tensile load values are 24500N (Method-1), 21560N (Method-2) and weight is decreased by 50% of conventional one.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.459-462
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• 2006

In this study, the characteristic of a vane pump of an automative power steering system is numerically analyzed. The vane pump changes the energy level of operation fluid by converting mechanical input power to hydraulic output. To simulate this mechanism, moving mesh technique is adopted. As a result, the flow rate and pressure are obtained by numerical analysis. The flow rate agrees well with the experimental data. Moreover, the variation and oscillation of the pressure around the rotating vane are confirmed. The difference of pressure appears in the vane tip as a result of the flow characteristics. Furthermore, the back flow into the rotor was observed.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.1
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• pp.58-63
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• 2009

Flow rate of the power steering oil pump is affected by oil temperature, engine rpm and pressure of pump. In this paper, considering those conditions, approximate model expressed by flow rate characteristics between hydraulic power steering oil pump and steering gear is proposed. Oil pump displacement is considered to be 9.6cc/rev. which is adapted to mid size car. Flow rate of the oil pump is predicted from the proposed model and compared with experimental data. And catch-up is also predicted in each steering wheel speed and is compared with experimental results.