• 한국자동차공학회논문집
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• 제22권1호
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• pp.174-182
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• 2014

Recently, not only common types of hybrid electric vehicle (HEV) such as series or parallel but many other types of HEVs including 4WD hybrid electric vehicle have been developed and released. In this study, analysis of fuel economy and driving performance for 2WD and 4WD HEV are conducted using backward simulation based on dynamic programming. To analyze the characteristics of 4WD HEV, tire slip model based on vehicle dynamics was applied to the backward simulation program. As a result, 2WD HEV shows better fuel economy than 4WD HEV because of relatively simple configuration. However, in a severe road condition, 4WD HEV shows better driving performance that 2WD HEV had about 6% of impossible time to follow the driving cycle though the 4WD HEV had no impossible time.

• 디지털융복합연구
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• 제10권1호
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• pp.379-384
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• 2012

조립공정의 상세한 과정을 보여주기 위해 Script 언어를 사용하여 자동차 조립공정을 3D로 시뮬레이션 하였다. 3D 가시화 기술은 산업현장에서의 학습활동을 가시화하는데 최적의 방법이 될 수 있다. 특히 시뮬레이션은 자동차 관련하여 엔진 부분과 타이어부분에 대하여 조립과정을 3D로 자동화하여 보여줄 수 있도록 구현하였다. 특히 터치스크린을 바탕으로 하여 사용자가 실제로 작업도중에 학습할 수 있도록 실험하였다.

• International Journal of Automotive Technology
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• 제7권7호
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• pp.803-812
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• 2006

In order to reduce the negative effects of dynamic coupling among vehicle subsystems and improve the handling performance of vehicle under severe driving conditions, a vehicle chassis control integration approach based on a main-loop and servo-loop structure is proposed. In the main-loop, in order to achieve satisfactory longitudinal, lateral and yaw response, a sliding mode controller is used to calculate the desired longitudinal, lateral forces and yaw moment of the vehicle; and in the servo-loop, a nonlinear optimizing method is adopted to compute the optimal control inputs, i.e. wheel control torques and active steering angles, and thus distributes the forces and moment to four tire/road contact patches. Simulation results indicate that significant improvement in vehicle handling and stability can be expected from the proposed chassis control integration.

• 한국자동차공학회논문집
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• 제23권4호
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• pp.361-370
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• 2015

There will inevitably be errors and uncertainties in tire yaw mark related critical speed formula, which is derived merely from the relationship between the centrifugal force and the friction force acting on the point-mass vehicle. Constructing and measuring yaw marks through appropriate simulation works have made it possible to perform uncertainty analysis in calculation of critical speeds under variation of variety of conditions and parameters while existing yaw mark experimental tests have not performed properly. This paper does not present only the critical speed analysis results for parametric sensitivity and uncertainty of chord and middle ordinate, coefficient of friction and road grade, but also modeling uncertainty such as variation of braking level during turning and vehicle size. The yaw mark analysis methods and results may be now applied in practice of traffic accident investigation.

• 한국공작기계학회논문집
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• 제14권6호
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• pp.68-73
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• 2005

Tire manufactures have dealt with noise problem by varying the pitch of the tread. The various formulas for the variations are generally determined differently, however. Often these variations are based on a combination of trial and error, intuition, and economics. Some manufactures have models and analogs to test tread patterns and their variations. These efforts, however practical, do not determine the best variation beforehand or guarantee the best results. For this reason it was felt that a general mathematical approach fur determining the best variation was needed. Moreover, the method should be completely general, easy to use, and sufficiently accurate. This paper discusses a mathematical method called Mechanical Frequency Modulation(MFM) which meets the above requirements. Thus, MFM pertains to computing an irregular time sequence of events so that the resulting excitation spectrum is shaped to a preferred form. The first part of this paper treats the theoretical basis for computing an optimum variation ; the second part discusses experimental results and simulation program which corroborate the theory.

• 전기학회논문지
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• 제63권1호
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• pp.162-172
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• 2014

A three-dimensional dynamic model for simulating various motions of full vehicle is presented. The model has 16 independent degrees of freedom (DOF) consisting of three kinds of components; a vehicle body of 6 DOF, 4 independent suspensions equipped at every corner of the body, and 4 tire models linked with each suspension. The dynamic equations are represented in six coordinate frames such as world fixed coordinate, vehicle fixed coordinate, and four wheel fixed coordinate frames. Then these lead to the approximated prediction model of vehicle posture. Both lateral and longitudinal dynamics can be computed simultaneously under the conditions of which various inputs including steering command, driving torque, gravity, rolling resistance of tire, aerodynamic resistance, etc. are considered. It is shown through simulations that the proposed 3D model can be useful for precise design and performance analysis of any full vehicle control systems.

• 한국전자통신학회논문지
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• 제6권2호
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• pp.180-185
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• 2011

TPMS(Tire Pressure Monitoring System)는 차량의 주행 또는 정차시 타이어의 압력 또는 온도 등에 따른 이상 유무를 측정하여 수신기의 표시장치에 해당 상황을 나타내주도록 설계된 안전 보조 시스템이다. TPMS의 센서부에서 측정한 데이터를 자동차 내부의 신호처리부로 무선통신을 이용하여 전송하는데, 통신 시에 다양한 간섭으로 인한 통신 장애가 발생할 수 있다. 대표적인 TPMS 간섭으로 아마추어 무선국, 컨테이너 관리용 RFID(Radio-Frequency IDentification), RKE(Remote Keyless Entry) 신호 등을 들 수 있다. 이러한 다양하면서도 높은 전력을 가지는 간섭들을 제거하기 위하여 본 논문에서는 빔형성(Beamforming) 기술을 고려한다. 이에 따른 데이터 구조 및 빔형성기에 알맞는 차량내부의 안테나 배치 등을 제안한다. 컴퓨터 시뮬레이션을 통하여 본 논문에서 제안된 기술의 간섭제거 성능을 확인 할 것이다.

• 한국전자통신학회논문지
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• 제7권3호
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• pp.499-505
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• 2012

TPMS(Tire Pressure Monitoring System)는 차량에서 사용되는 무선통신기기의 일종으로 운전자가 타이어의 상태를 보다 효율적으로 파악하고 관리하기위한 안전보조 시스템으로 정의할 수 있다. TPMS는 무선통신을 사용하므로 데이터 송/수신 시 각종 잡음이나 간섭에 의한 통신장애가 발생하게 된다. 운전자의 안전과 직결되는 타이어 사고를 사전에 예방하고 무선통신으로 인한 데이터 전송 시 보다 정확한 데이터 신뢰성 확보를 위해 본 논문에서는 신호처리수신부에서 수신신호의 SINR(signal-to-interference and noise ratio, 신호 대 간섭 및 잡음 비)을 측정하여 데이터 신뢰도를 판정하는 신뢰도 판정기법을 제안한다. 또한, 이를 수행하기 위한 효과적인 데이터 신뢰성 판정 알고리즘 구조를 제안한다. 본 논문에서 제안된 데이터 신뢰성 판정기법은 TPMS 뿐만 아니라 센서를 이용한 양방향통신 시스템에서 폭넓게 사용될 수 있을 것으로 판단되다. 컴퓨터 시뮬레이션을 통해 95%, 97%, 99%의 데이터 신뢰도를 만족하는 임계 SINR 값을 확인한다.

• 산업공학
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• 제23권2호
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• pp.89-99
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• 2010

Containers are commonly used as an effective and relatively inexpensive method for transporting goods. Unfortunately, there are often imbalances between the number of import and export containers, and some ports have a surplus of empty containers while others have a deficit. The Empty Container Simulation Game was developed to address these problems. The game is a computer role playing simulation that simulates the distribution of empty containers in order to solve empty container imbalances among ports. An optimal solution is obtained by the computer using linear programming (LP). Upon completion of the game, a player's game results are displayed along with the LP solution. The game interface was designed to provide easy access and operation. This game will serve to provide an easy understanding and planning for empty container management.

• 산업공학
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• 제4권1호
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• pp.71-81
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• 1991

Presented in this paper is a systematic approach to "modeling and simulation' of flow lines in mass production systems, using a tire trimming line as an example. The "modeling phase" consists of 1) generation of alternative line configurations, 2) construction of a reference model for each alternative, and 3) formal description of the target system. ACD(Activity Cycle Diagrams) are employed as a tool for formal description. In the "simulation phase'. block diagram models (provided by the simulation language SIMAN) and the next event methodology(implemented in FORTRAN 77) are combined in order to fully describe the flow line behavior.