• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.887-890
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• 1996

In this study, based on the assumption that the displacements of suspension systems under the external forces are very small, a linear form of elastokinametic equations in terms of infinitesimal displacements and joint reaction forces are derived. The equations can be applied to any form of suspensions once the type of kinematic joints and bushings are identified. The validity of the method is proved through the comparison of the results from the more complex solution offered by ADAMS

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.10a
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• pp.345-350
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• 1996

The suspension system plays an important role in vehicle performance. To improve suspension characteristics related to riding comfort and handling stability simultaneously, active suspension system is developed. In this study, a hybrid control scheme is proposed, the idea of which is that the sliding mode control is applied to nonlinear hydraulic system and the skyhook control is applied for controlling the motion of the suspension system. The performance of the proposed control method is evaluated by simulation and experiment of a half car active suspension system.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.5
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• pp.132-139
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• 1997

It is difficult for most of passenger cars to attach various types of suspensions. The modular experimental vehicle, which is designed to exchange suspension systems, has been developed to evaluate the effect of design changes of a suspension upon ride and handling characteristics of a vehicle. In order to enable the assemblage between modules, the experimental vehicle design is based on a space frame construction through finite element analysis. Moreover, module frames and brackets are designed using three-dimensional solid modeler to check the interference between each part of a vehicle. Steady-state and transient road tests were performed. Multibody dynamic model and simplified linear vehicle model are made to compare with the tests. The results of simulations and tests show the performance and validity of this experimental vehicle.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1051-1056
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• 2007

The air suspension system is widely used in commercial vehicles such as buses or special purpose trucks because it improves ride better than any other types of suspension. Since the durability of vehicle parts is directly related to the safety, the evaluation of the durability at the design stage is necessary. In this research, the fatigue life of the air suspension frame for trucks is predicted by the modal stress recovery(MSR) method. Using the process proposed in this research, the fatigue life of vehicle parts can be predicted efficiently at the design stage.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.847-851
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• 1996

In this study, in order to adapt various types of suspensions that is not possible for a passenger car, and to validate the effect of the design change of a suspension upon ride and handling characteristics of vehicle, the modular experimental vehicle, which makes possible to exchange suspension systems, has been designed and developed. In order to enable the assemblage between the modules, the experimental vehicle design is based on a space frame construction through finite element analysis. Moreover, the module frames and the brackets are designed are designed using three- dimensionalsolid modeler to check the interference between each part of a vehicle. The results of simulation and experiment are compared.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.3
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• pp.419-425
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• 1988

It would be very useful if the dynamic response of a vehicle over rough ground could be predicted at the early design stage. This became more promising with the recent progress in computer hardware and software technologies. In this study, a model of a passenger car has been developed for the analysis of its dynamic response. This model can be easily used for the other passenger cars with little modification. This passenger car was modeled to be composed of lumped masses, rigid bodies, and the suspension systems with nonlinear properties. Even though a commercial dynamic simulation program, ADAMS, was used in this study, the developed model is valid for any other simulation program. Finally, the validity of the developed model and the analysis result was verified by an experiment.

• Journal of Korean Society of Steel Construction
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• v.12 no.1 s.44
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• pp.83-91
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• 2000

The first Procedure to identify structural system by using measured data is transformation of data to frequency domain and try to recognize modal characteristics in graphical condition. Those methods are doubted about the reliability to the civil structures, especially bridges which has coupled and close modal characteristics. In this paper, feasibility of time domain modal Identification methods were examined and applied double least square method to overcome bias characteristics of the identification methods. To show the advantage of proposed method, simulation were carried out for mass-spring model. And to examine the usage of the method in realistic case, sensitivity of the methods to noise was performed.

• Transactions of the Korean Society of Mechanical Engineers
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• v.8 no.4
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• pp.335-342
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• 1984

본 연구에서는 무부하상태의 기관회전에 따른 차체진동특성을 해석하기 위한 모델로서 차체질량계를-선형적 특성을 갖는 스프링 및 함쇠기(shock absorber)로 연결 된-기관계와 현가질량계로 분리하고 국내상샌의 승용차를 대상으로 하여 10자유속계의 동력학적 모델을 구성한다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.11
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• pp.1105-1111
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• 2015

The exhaust system is one of the major sources of vibrations, along with the suspension system and engine. When the exhaust system is connected directly to the engine, it transfers vibrations to the vehicle body through the body mounts. Therefore, in order to reduce the vibrations transmitted from the exhaust system, the vibration characteristics of the exhaust system should be predicted. Thus, the dynamic characteristics of the bellows, which form a key component of the exhaust system, must be modeled accurately. However, it is difficult to model the bellows because of the complicated geometry. Though the equivalent beam modeling technique has been applied in the design stage, it is not sufficiently accurate in the case of the bellows which have complicated geometries. In this paper, we present an improved technique for modeling the bellows in a vehicle. The accuracy of the modeling method is verified by comparison with the experimental results.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.1
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• pp.71-78
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• 2002

This paper is concerned with the design and implementation of magnetic damper system to reduce the vibration of suspension system actively. Cylindrical type electro-magnetic actuator with permanent magnet is analyzed and effective controller design is made. Magnetic force analyzed and transfer function for the total system is determined by experimental data using error minimization method. For experiments, simple suspension structure system is utilized, in which a magnetic damper composed of permanent magnet and digital controller is attached. In order to drive the system, bipolar power amplifier of voltage control type is utilized. Stable and high speed control board is used to perform digital control logic for the given system. This paper shows that the magnetic damper system using phase-lead controller excellently reduces vibration of 1-D.O.F (degree of freedom) suspension system.