• 한국자동차공학회논문집
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• 제14권6호
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• pp.57-65
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• 2006

An approximate function approach has been developed using the subsystem synthesis method for real-time multibody vehicle dynamics models. In this approach, instead of solving loop closure constraint equations of the suspension linkage, approximate functions are used. The approximate function represents the functional relationship between dependent coordinates and independent coordinates of the suspension subsystem. This kinematic relationship is also included in the suspension subsystem equations of motion. Different order of polynomial functions are tried to find out the best candidate functions. The proposed method is also compared with the conventional subsystem synthesis method to verify its efficiency and accuracy.

• 한국자동차공학회논문집
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• 제10권3호
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• pp.185-191
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• 2002

A window-based multibody dynamics program CADyna(Computer Aided Dynamics) is developed and applied for kinematic and dynamic analysis ova steering system. The program is composed oft pre-processor, a main processor, and a post-processor. The pre-processor is developed with Visual C7+ and the post-processor is developed with OpenGL and TeeChart. The main processor generates the equations of motion employing velocity transformation technique. The developed program is customized for the design of an intermediate shaft in a steering system.

• 대한기계학회논문집A
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• 제33권1호
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• pp.89-97
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• 2009

In this paper, a computer software for dynamic analysis of a high mobility tracked vehicle with pre/post processor is developed. Model of a tracked vehicle is composed of chassis, turret, mount, gun, and road-wheel assembly. Track is modeled as an extensible cable and the track tensions are applied on the wheels as external forces. The system equations of motion and constraint acceleration equations are derived in the joint coordinate space using the velocity transformation method. The pre and post processors are developed using the Visual C++.

• 대한기계학회논문집A
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• 제35권8호
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• pp.863-867
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• 2011

본 논문에서는 우등버스용 MR 댐퍼의 특성 시험 결과를 분석하고, 비선형 히스테리시스 특성을 모델링할 수 있는 실험적 모델링이 제시된다. MR 댐퍼의 인가전류에 따른 실험적 모델을 구성하고, 매트랩의 최적설계 툴 박스를 이용하여 계수를 규명한다. 우등버스의 전차량 시뮬레이션을 통하여 차량동역학 해석용 MR 댐퍼의 실험적 모델의 유용성을 검증한다.

• 한국자동차공학회논문집
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• 제14권2호
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• pp.158-165
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• 2006

In this paper, a new uni-axial bushing model for vehicle dynamics analysis is proposed. Bushing components of a vehicle suspension system are tested to capture the nonlinear and hysteric behavior of the typical rubber bushing elements using the MTS machine. The results of the tests are used to develop the Bouc-Wen bushing model. The Bouc-Wen model is employed to represent the hysteretic characteristics of the bushing. ADAMS program is used for the identification process and VisualDOC program is also used to find the optimal coefficients of the model. Genetic algorithm is employed to carry out the optimal design. A numerical example is suggested to verify the performance of the proposed model.

• 한국자동차공학회논문집
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• 제9권2호
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• pp.176-184
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• 2001

The VDC(Vehicle Dynamics Control) is a control system whose target is to improve vehicle stability under critical motion. The system has a good potential of becoming a standard active safety unit in passenger vehicles since it can be implemented on top of the ABS/TCS system with little extra cost. This, however, is possible only when the signals that the VDC system demands can be obtained with sufficient accuracy. In this research, estimators for the road friction coefficient and body sideslip angle have been designed. The two variables have great influence upon performance of the VDC system but not directly measurable. For the estimator design, the Newton method and the nonlinear observer theory have been exploited. The performance of the estimator have been verified via simulations on critical driving conditions.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.864-869
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• 2004

In this paper, a blackbox approach is carried out to model the nonlinear dynamic bushing model. One-axis durability test is performed to describe the mechanical behavior of typical vehicle elastomeric components. The results of the tests are used to develop an empirical bushing model with an artificial neural network. The back propagation algorithm is used to obtain the weighting factor of the neural network. Since the output for a dynamic system depends on the histories of inputs and outputs, Narendra's algorithm of 'NARMAX' form is employed in the neural network bushing module. A numerical example is carried out to verify the developed bushing model.

• 한국자동차공학회논문집
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• 제21권2호
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• pp.122-130
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• 2013

Rail geometries such as cant, grade and curvature can be easily represented by means of a track coordinate system. In this analysis, in order to derive a dynamic and constraint equation of a wheelset, the track coordinate system is used as an intermediate stage. Dynamic and constraint equations of railway vehicle bodies except the wheelset are written in the Cartesian coordinate system as a conventional method. Therefore, whole dynamic equations of a railway vehicle are derived by combining wheelset dynamic equations and dynamic equations of railway vehicle bodies. Constraint equations and constraint Jacobians are newly derived for the track coordinate system. A process for numerical analysis is suggested for the derived dynamic and constraint equations of a railway vehicle. The proposed dynamic analysis of a railway vehicle is validated by comparison against results obtained from VI-RAIL analysis.

• 한국정밀공학회지
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• 제13권10호
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• pp.30-35
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• 1996

Tires, bushings and stabilizers are the most difficult elements in vehicle modeling for dynamic analyses. Many studies were performed for tire modeling and the primitive data of bushing elements can be obtained from the suspension designer, but there are few things for stabilizer. This paper presents simulation results for the 3 kinds of stabilizer model with the multi-body dynamic analysis program ADAMS. Each simulation result was compared with the vehicle test result, and the stabilizer model was proposed to analyze the vehicle behaviors precisely.

• 한국자동차공학회논문집
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• 제14권4호
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• pp.199-206
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• 2006

Real time vehicle dynamics models have been developed with the subsystem synthesis method for intelligent vehicle HILS system. Three different models for solving subsystem equations are compared in order to find out the best suitable model for HILS applications. The first model is based on the generalized coordinate partitioning technique, and the second one is on the approximate function approach, and the last one is on the constraint stabilization method. To investigate the theoretical efficiency of three proposed methods, arithmetic operators used in the formulations of three models are counted. Bump run simulations with half-sine bump have also carried out with three different models to measure the actual CPU time to validate theoretical investigation.