• 한국정밀공학회지
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• 제15권1호
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• pp.160-168
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• 1998

In this paper. the Joint reaction forces in the suspension system of a passenger car are determined to calculate the deflections and stresses in the damper strut. A mathematical model of the Roll Stabilizer Bar(RSB) is developed to include the RSB forces in the dynamics analysis. Using these RSB forces, the variations of the damper forces and spring forces due to the wheel strokes are determined in a McPherson strut suspension. The graphs of shear force diagram, bending moment diagram, bending stress and deflections are drawn by the calculated joint reaction forces.

• 전기학회논문지
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• 제64권7호
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• pp.1074-1080
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• 2015

In the last decades, the increasing interest in unmanned aerial vehicle(UAV) for military, surveillance, and rescue applications made necessary the development of flight control theory and body structure more and more efficient and fast. In this paper, we describe the design and performance of a prototype hexarotor UAV platform featuring an inertial measurement unit(IMU) based autonomous-flying for use in bluetooth communication environments. The proposed system comprises the construction of the test hexarotor platform, the implementation of an IMU, dynamic modeling and simulation in the hexarotor helicopter. Furthermore, the hexarotor helicopter with implemented IMU is connected with a micro controller unit(ARM-cortex) board. The P-PD control algorithm was used to control the hexarotor. We used the Matlab software to help us to tune the P-PD control parameters for quick response and minimizing the fluctuation. The control simulation and experiment on the real system are implemented in the test platform, evaluated and compared against each other.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.1383-1384
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• 2015

In this paper, a dynamics model embedded navigation filter is newly suggested for underwater autonomous systems without position or attitude aid. In order to ensure the observability on the INS errors, the hydrodynamics of the underwater vehicle is incorporated with the INS attitude error. This approach allows us to estimate and compensate the INS errors in spite of using external velocity sensor. Through the simulation, the performance and effectiveness of the proposed scheme are demonstrated.

• 한국정밀공학회지
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• 제16권5호통권98호
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• pp.19-28
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• 1999

In this study, a real-time simulation system and a washout algorithm for an excavator have been developed for a driving simulator with six degrees of freedom. The excavator model consisting of a boom. bucket, upper frame, lower frame and four wheels, has total 11 degrees of freedom. The suggested washout algorithm consists of high and low pass filters with second order. The high pass filters cut off low frequency of the motion cues limited by platform motion. The cut off frequency for the tilt coordination are suggested for a realistic regeneration of excavator motion.

• 소음진동
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• 제7권2호
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• pp.239-246
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• 1997

This paper presents an active suspension control algorithm to improve the suspension performance trade-offs between riding comfort and handling stability. In this paper, a hybrid control scheme is proposed, the idea of which is that sliding mode control is used for nonlinear hydraulic system and the skyhook control is applied to control the vehicle behavior. The parameter variations in hydraulic system are considered for the robust controller design. The performance of the proposed control method is evaluated by simulation and experiments based on a half car roll model which can reveal both heave and roll behavior.

• 한국자동차공학회논문집
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• 제21권1호
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• pp.78-85
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• 2013

This paper presents the sliding mode control methods for anti-lock brake system (ABS) with the friction force observer. Using a simplified quarter car model, the sliding mode controller for ABS is designed to track the desired wheel slip ratio. Here, new method to find the desired wheel slip ratio which produces the maximum friction force between road and tire is suggested. The desired wheel slip ratio is varying according road and tire conditions to produce maximum friction force. In order to find optimum desired wheel slip ratio, the sliding mode observer for friction force is used. The proposed sliding mode controller with observer is evaluated in simulation, and the control design is shown to have high performance on roads with constant and varying adhesion coefficients.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.653-658
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• 2009

This paper describes the structural deflection analysis method and result of EMU(Electric Multiple Units). During manufacturing of rail passenger coaches, the underframe is assigned a camber before it is integrated with other major assemblies of shell such as the side panel, the end panel and the roof. The camber of the positive deflection given intentionally to compensate for the sagging so that it remains straight at the maximum load. But some manufacturers have insisted there has no relationship between the camber and the safety or life cycle and they expect to reduce a manufacturing cost without a camber. So this study analyzes whether the camber influences on the safety or life cycle of EMU structure under a full load and regular driving condition. The structural dynamics model for a railway vehicle is introduced.

• Journal of Power Electronics
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• 제16권6호
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• pp.2016-2023
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• 2016

This paper presents a simple input-constrained current controller for a DC/DC boost converter with stability analysis that considers the nonlinearity of the converter model. The proposed controller is designed to satisfy the inherent input constraints of the converter under a physically reasonable assumption, which is the first contribution of this paper. The second contribution is providing a rigorous proof of the proposed control law, which keeps the closed-loop system along with the internal dynamics stable. The performance of the proposed controller is demonstrated through an experiment employing a 20-kW DC/DC boost converter.

• 대한전기학회논문지:시스템및제어부문D
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• 제50권1호
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• pp.31-37
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• 2001

A robust adaptive technique for the longitudinal control of a platoon of automated vehicles is presented. A nonlinear model is used to represent the dynamics of each vehicle within the platoon. The external disturbances such as wind gust and a disturbance term due to engine transmission variations and so on are considered. The state observer is used to avoid direct measurement of the relative velocity or acceleration between the controlled and leading vehicles or the controlled vehicles's acceleration. The proposed controller guarantees to recover platoon stability in operation even if a speed dependent spacing policy is adopted, which incorporates a constant time headway in addition to the constant distance. It is shown that the proposed observer is exponentially stable, and the at the robust adaptive controller is stable. The simulation results demonstrate excellent tracking even in the presence of disturbances.

• 한국가스학회지
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• 제25권2호
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• pp.13-21
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• 2021

최근 수소자동차 보급의 확대로 수소충전소의 설치가 점차 확대될 예정이다. 본 연구에서는 수소충전소의 최악의 상황을 가정한 시나리오를 기반으로 피해규모를 예측하고 보다 안전한 설계형태를 제안하고자 한다. 피해규모 예측 방법은 전산유체역학(CFD)을 이용한 Flacs solver를 사용하였으며 이전 연구자의 실험 결과와 비교하여 정확성을 검증하였다. 피해규모 예측은 수소누출과 폭발에 대해서 실시하였으며, 예측 대상은 실측치를 기반으로 한 KR model로 하였다. 그리고 비교검토 모델로는 천정이 없는 형태인 Roofless model을 선정하였다. 두 모델에 대하여 분석한 결과 KR model에서는 내부가 60 vol% 이상까지 수소가스가 누적·체류되는 현상을 확인 할 수 있었던 반면, Roofless model의 경우에는 누출 후 벽면을 타고 충전소 외부로 방출·확산되는 현상을 확인 할 수 있었다. 결론적으로 국내에 표준모델로 보급·확산되고 있는 수소충전소 모델보다는 천정이 없는 수소 충전소 형태가 안전상 유리한 것으로 검토되었다.