• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.413-418
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• 2005

Vibration test using the MAST(Multi Axial Simulation Table) is more reliable test than conventional testing process focused on one directional vibration test. The former test could be possible with a advanced control algorithm and hardware supports so that most of the operation is automatically conducted by MAST system itself except the input information that is derived from the measured data. That means the reliability of the vibration test is highly depended on the input profile than any other cases before. In this paper, the optimal algorithm based on energy method is introduced so that the best combination of candidated input PSD data could be constructed. The optimal algorithm renders time information so that the vibration fatigue test is completely possible for any measured signals one wants. The real road test is conducted in short intervals containing some rough roads and the candidated input PSD is obtained from the extra road in proving ground. The testing is targeted for the electronically operated door and seat.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.6
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• pp.1464-1473
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• 1990

Optimal design parameters are estimated from the sensitivity function and performance index variation. Suspension design modification for performance improvement and basic materials for practical applications are presented. The linear quarter model of a vehicle suspension is analyzed in order to represent the utilities of sensitivity analysis, and sensitivity function is determined in the frequency domain. The change of frequency response function is predicted, which depends on the design parameter variation and the property is verified by computer simulation. As an investigation results of sensitivity function for the vibrational amplitude of sprung mass to road profile input, it is shown that the most sensitive parameters are the suspension damping and the suspension stiffness. In order to identify the effects of these two parameters to the performance of suspension system, the performance index variation according to the changes of parameters is considered and then optimal design parameters are determined. It is verified that the system response is improved noticeably in the both of frequency and time domain after the design modification with the optimal parameters.

• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.71-74
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• 2008

This paper aims at studying the key design elements for the optimal ventilation system design, developing the design models and suggesting the design guidelines. The key elements include the basic exhaust emission rate, wall friction coefficient, vehicle drag coefficient and slip streaming effect, jet fan operating efficiency, natural ventilation force and installation scheme for jet fans and ventilation monitors in tunnel. The design models developed in this study are one-dimensional ventilation simulator to analyze the air flow, pressure profile and pollutant dispersion inside and outside tunnel, expert model to choose the optimal ventilation method, and the ventilation characteristic chart to evaluate the preliminary ventilation system. The study results are reflected in the design guideline for road tunnel ventilation system.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.117.5-117
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• 2001

This paper presents the key idea of handlebar reaction force and pedal resistance force generation in creating life-like feeling in KAIST bicycle simulator. Also, it provides methods to evaluate its reality level with given reaction force profile. In KAIST bicycle simulator, the pedal resistance force and the handlebar reaction force are calculated using the bicycle dynamic model. With the information handlebar angle, rider´s pedaling torque and road profile transmitted from the handlebar system, the pedal system and the visual part, the bicycle dynamics engine calculates the handlebar reaction force and the pedal velocity. The handlebar system and the pedal resistance system generate reaction force and resistance force transmitted from dynamics engine. However to make more realistic riding feeling ...

• Journal of IKEEE
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• v.22 no.1
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• pp.29-37
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• 2018

In recent years, there have been increasing interests in the mobile crowdsourcing that exploits multiple sensors, communication and user interfaces, and the computation power of widespread smartphones. In this paper, we present a novel mobile crowdsourcing-based driver assistance systems (MC-DAS) that crowdsource the sensor data of smartphone app having already passed a road segment, generate its profile information through a massive data processing, and forward this profile to the smartphone app of vehicle entering the road segment. Based on the MC-DAS platform, we also design and implement a new navigation system that advices the vehicle speed depending on the speedbump and on the road curvature profile. We expect that the proposed MC-DAS platform will be used as a platform for emerging new mobile crowdsourcing applications.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.293-298
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• 1993

In ground vehicles, the increasing demand for safety and ride comfort which are trade-off relation, especially at high speeds, has led to the development od actively controlled suspensions. The LQG/LTR controller can be used to design a robust feedback control system that deals with disturbance rejection properties as well as insensitivity to modelling errors and sensor noise. And when the disturbance can not be measured but is limited within a certain frequency range, a bandpass feedback to eliminate the disturbance response can be used. In this paper, hybrid controller cosisted of bandpass feedback controller and LQG/LTR controller is applied to a quarter-car model moving on a randomly profiled road. The random road profile considered as colored noise is shaped from white noise by use of shaping filter. The performance of the hybrid control system is compared with that of an LQG/LTR controlled system.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.7
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• pp.74-81
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• 1995

In this paper, a composite controller cosisted of bandpass feedback controller and LQG/LTR controller is applied to a quarter-car model moving on a randomly profiled road. The LQG/LTR controller is used to achieve a design transfer toop. A bandpass feedback controller is adopted to eliminate the response due to the disturbance, which generally can not be measured, confined within an interested frequence range. The random road profile considered as colored noise is shaped from white noise by use of shaping filter. The performance of the composite control system is compared with that of an LQG/LTR control system.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.355-358
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• 1996

Electrical Power System (EPS) of Electric Vehicle which consists of batteries, motor and driving subsystem, has been modeled. A battery model is modeled with an electrical circuit representing a characteristics of real battery. Driving subsystem is modeled as three different level namely exact, average and functional models. Load profile includes road information, speed profile and EV mechanical parameters, which are incorporated into a reference torque in the driving subsystem model. A system model is integrated to simulate the performance of electric vehicle such as energy balance, battery status, and electrical stress of each subsystem.

• Proceedings of the KIEE Conference
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• 1999.07b
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• pp.841-843
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• 1999

This paper presents a design of stabilization controller for combat vehicle. A Stabilization system reject disturbances while vehicle moving. The conventional stabilization controller used to constant gain. We can improve the aiming performance by appropriate controller gain. We can find the proper controller gain for road frequencies by evolution strategy(ES). The relationship between the frequencies and proper control gains are generalized by use of the neural network. The road frequency estimated by wavelet transform of disturbance signal. The simulation result show that proposed controller is superior to the conventional stabilization controller.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.871-875
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• 1996

The Output feedback linear quadratic regulator control is applied to the design of active suspension system using 7 DOF full car model. The performance index reflects the vehicle vertical movement, pitch and roll motion, and minimization of suspension stroke displacements in the rattle space. The elements of gain matrix are approximately decoupled so that each suspension requires only local information to generate the control force. The simulation results indicates that the output feedback LQ controller is more effective than purely passive or full state feedback active LQ controllers in following the road profile at the low frequency range and suppressing the road disturbance at the high frequency ranges.