• Journal of ILASS-Korea
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• v.19 no.1
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• pp.40-46
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• 2014

Recently rise in oil prices feet the burden on not only diesel vehicle driver but also LPG vehicle driver, and get interested in various way to reduce fuel costs. In this study discuss on exhaust emissions characteristics on driving cycle mode and ignition advance condition change of CNG/LPLI Bi-Fuel vehicle. Experimental test was performed by changing the conditions of fuel (LPG/CNG), spark advance (Base, $10^{\circ}CA$, $15^{\circ}CA$), and driving mode (FTP-75, HWFET, and NEDC). In case of CO emission, in the order of CNG Base, CNG S/A10, S/A15 condition are average reduced -21%, -35%, -29% respectively compared to LPG fuel. The active emission reduction from the initial engine start, spark retard is likely to be beneficial in catalyst warm-up and improve combustion stability rather than spark advance.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.6
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• pp.74-80
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• 2009

Path tracking of unmanned vehicle is a basis of autonomous driving and navigation. For the path tracking, it is very important to find the exact position of a vehicle. GPS is used to get the position of vehicle and a direction sensor and a velocity sensor is used to compensate the position error of GPS. To detect path lines in a road image, the bird's eye view transform is employed, which makes it easy to design a lateral control algorithm simply than from the perspective view of image. Because the driving speed of vehicle should be decreased at a curved lane and crossroads, so we suggest the speed control algorithm used GPS and image data. The control algorithm is simulated and experimented from the basis of expert driver's knowledge data. In the experiments, the results show that bird's eye view transform are good for the steering control and a speed control algorithm also shows a stability in real driving.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.2
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• pp.192-198
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• 2001

In this study, a methodology of synchronous control which can be applied to position synchronization of a two-axes driving system has been developed. The synchronous error is caused by model uncertainties and torque disturbance of each axis. To overcome these problems, the proposed synchronous control system has been composed of two speed controllers and one synchronous controller. The speed controllers based on PID control law are aimed at the following to speed reference. And the parameters of speed controllers have been designed in order that speed response of the second axis corresponds with one of first axis. Especially, considering to model uncertainties of each axis, the synchronous controller has been designed using H$\infty$ control theory. The controller eliminates the synchronous error by controlling speed of the second axis. The effectiveness of the proposed method has been verified through simulation.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.612-618
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• 2009

Recently the roles of railways about the prevention of global warming caused by greenhouse gases and for low carbon green growth are larger than ever. And the railroad-related research institutions have been active in researching for energy conservation. Especially the urban railroad has been emerged as the best means of transportation compared to the general public transportation systems in punctuality, stability, ecology and etc. In operating the urban railroad system there are various ways for energy savings. In the larger category, One is the hardware aspect according to the structure of the vehicle and the development of control systems. The other is the software aspect which efficient train operation can be made through control of driving patterns and driving diagram. In this paper, there is sense to analyze the result in verifying expectation relation with variable and the use of electric power on this after selecting main variables that can influence to the energy of the train operation in the software aspect. First, after collecting the basic data related to operation(train speed, operating hours, power consumption, the position of stopping station, electrical power system etc.) and according to this, investigating the consumption of the energy of the operation, in the side of energy consumption deducing and analyzing problem, this will be found solutions.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.9
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• pp.146-157
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• 1999

Safety systems for road vehicles have been rapidly developed in recent years. Especially, the VDC(Vehicle dynamics Control) system is a new active safety system for road vehicles which controls its dynamic vehicle motion in emergency situations . In the case of configuring the VDC system by utilizing the ABS(Anti-lock Brake System), the role of a control logic which directly influences the vehicle motion is very important. In this study the performance of the VDC vehicle was compared to the performances of the CBS (Conventional Brake system )and ABS vehicle. For various driving conditions , the simulation of vehicle dynamics with known VDC control logics was performed. Analysis results showed the VDC vehicle could stably perform even on the road of low coefficient of friction. In addition it was shown that the basic control logic for the VDC system could outstandingly improve driving stability in the case of braking as well as constant speed cruising.

• Journal of the Korean Society of Industry Convergence
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• v.18 no.2
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• pp.67-74
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• 2015

Two-wheeled driying mobild robots are precise controlled in terms of linear contol methods without considering the nonlinear dynamical characteristics. However, in the high maneuvering situations such as fast turn and abrupt start and stop, such neglected terms become dominant and heavy influence the overall driving performance. This study describes the nonlinear optimal control method to take advantage of the exact nonlinear dynamics of the balancing robot. Simulation results indicate that the optimal control outperforms in the respect of transient performance and required wheel torques. A design example is suggested for the state matrix that provides design flexibility in the control. It is shown that a well-planned state matrix by reflecting the physics of a balancing robot greatly conrtibutes to the driving performance and stability.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.239-243
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• 2006

A noise/vibration of the forklift happens in the driving axle to charge the drive and are examined closely by an each reason. After this study consider a reduction method of a noise/vibration about the gear, axle, bearing and others, the purpose of this study is to reduce a noise/vibration for a stability of the total system. From the data to be measured through all experimental method, the problems of the gear, axle, bearing, housing and others are examined closely, and the forklift is derived the model to be the engineering. The Mechanism of the problem occurrence is examined through a palametric research about an each influence factor. Lastly, the resuls of this study propose the model to he improved.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.3
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• pp.569-574
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• 2010

The full bridge converter have been used for high power system that is needed to switch the big current. So, EMI and stability problem is occurred. The Soft switching method is the solution to solve the above problem, But implementation of soft switching(ZVS: Zero Voltage Switching) is so complicate and expensive because of the DSP MCU and shift circuit. In this paper, we introduce the technical method for driving circuit of ZVS full bridge converter with 1st order delay circuit and logic elements. The realization of this method is so simple and cheap. The effectiveness of the proposed circuit is verified by experimental results.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.12 s.189
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• pp.46-55
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• 2006

A robust motion controller based on self-organizing fuzzy control(SOFC) and feed-back tracking control technique is proposed for a two-wheel driven mobile robot. The feed-back control technique of the controller guarantees the robot follows a desired trajectory. The SOFC technique of the controller deals with unmodelled dynamics of the vehicle and uncertainties. The computer simulations are carried out to verify the tracking ability of the proposed controller with various driving situations. The results of the simulations reveal the effectiveness and stability of the proposed controller to compensate the unmodelled dynamics and uncertainties.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.4
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• pp.549-554
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• 2012

Noncontactable joystick for a low speed electric vehicle(LSEV) is developed. The joystick is proposed to replaced the steering wheel in a conventional LSEV. The main advantages of the proposed joystick are a durable and a stable in structure, simple and easy to control through discriminating the driving and braking area. To reduce error and stability in the joystick control, input and output signal of the joystick are manipulated by data averaging and differntiation. With this algorithm, the driving resolution and capability are improved. To verify the proposed algorithm, a simple prototype model which has two electric motors for propulsion and steering are used. Test results show that the prototype joystick control system is applicable to an LSEV dirve.