• Proceedings of the KSR Conference
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• 2007.11a
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• pp.917-922
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• 2007

Electromagnetic suspension, the suspension system used for Maglev trains, is now being applied to urban and inter-city transportation systems, offering environmental benefits. This suspension system is actively controlled to stabilize the suspended vehicle as it runs over an elevated guideway, which, for various reasons, may have deviations in its height. For this reason, frequency responses of the suspension to height deviations must be predicted in the system design cycle. The equations of motion of the electromagnetic suspension employing the 5 state feedback control law are derived for frequency analysis. The results of this paper could be used to determine design requirements for the urban Maglev transportation system currently under development in Korea.

• Transactions of Materials Processing
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• v.16 no.3 s.93
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• pp.201-209
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• 2007

Generally, the forming process of suspension system parts have been considered only considered with the formability and have not been considered with the durability of suspension system. But the durability of suspension system is very important characteristic for the dynamic performance of vehicle. Therefore, the suspension system should be manufactured to consider the durability as well as the formability. This paper is about an optimum forming process design with the effect of section properties to consider the roll durability of torsion beam type suspension. In order to determine the tube hydroforming process for the satisfaction the roll durability, the stamping and hydroforming simulation by finite element method were performed. And the results from finite element analysis and roll durability examination showed the tube hydroforming process of torsion beam is optimized as satisfying the durability performance.

• Structural Engineering and Mechanics
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• v.44 no.3
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• pp.363-378
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• 2012

The stiffness of a suspension system is provided by the bushings and the stiffness of the wheel center controls the suspension's elasto-kinematic (e-k) specification. So the stiffness of the wheel center is very important, but the stiffness of the wheel center is very hard to measure. The paper give a new method that we can use the stiffness of the bushings to calculate the equivalent stiffness of the wheel center, which can quickly and widely be used in all kinds of suspension structure. This method can also be used to optimize and design the suspension system. In the example we use the method to calculate the equivalent stiffness of the wheel center which meets the symmetric and positive conditions of the stiffness matrix.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.4
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• pp.683-692
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• 2002

The most important parameter for hydraulic active suspension system is to sustain desirable vehicle maneuvering stability and ride comfort without increasing power consumption. The performance of hydraulic active suspension system depends on damping force of body damping valve and piston damping valve. Hydraulic actuator design and damping valve parameter selection are essential and basic procedure to design hydraulic system. This paper is on computer simulation with use of mathematical model that was delivered from dynamic characteristic of hydraulic actuator, as know basic damping characteristics of hydraulic active suspension system. The aim of this paper is to select the system parameter that affect mainly hydraulic active suspension, and identify the validity on the system parameter selection.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.509-512
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• 1995

A new modeling incorporating the role of control arm is proposed for the Macpherson type suspension system. Vertical displacement of the sprung mass and angular displacement of the control arm are selected as main control variables in the new modeling. With the same values of suspension vehicle parameters the conventional modeling and the new modeling are compared in terms of open loop characteristics.

• 제어로봇시스템학회:학술대회논문집
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• 1995.10a
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• pp.287-290
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• 1995

Recently H$_{\infty}$ control theory for nonlinear systems based on the Hamilton-Jacobi inequality has been developed. In this paper, we apply the state feedback controller solved via Riccati equation to a semi-active suspension model, two degree of freedom vehicle model, and show that it is effective for vibration control..

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.217-217
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• 2000

A decentralized robust EA(eigensoucture assignment) controller is designed for an active suspension system of a vehicle based on a full car model with 7-degree of freedom. Using overlapping decomposition, the full car model is decentralized by two half car models. For each half car model, a robust eigenstructure assignment controller can be obtained by using optimization approach. The performance of the decentralized robust EA controller is compared with that of a conventional centralized EA controller through computer simulations.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.1
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• pp.110-123
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• 2000

In this Study, the dynamic equation for vibration analysis of mechanical systems with kinematic constraints is derived. This equations are derived in terms of small displacements of Cartesian coordinates, and are applied to compute the dynamic response and the natural modes of the suspension system of a vehicle. The results are validated through the comparison with the results from conventional nonlinear dynamic analysis and modal test.

• Transactions of the Korean Society of Automotive Engineers
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• v.25 no.3
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• pp.344-349
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• 2017

Suspension noise from under a passenger car is one of the important factors that impact the perceptual quality for drivers. However, it is difficult to validate this by component level testing in the early stage of development, because suspension noise caused by interaction of the related parts has been found at saleable vehicles late during development or at the manufacturing stage, when many customers have already filed for claims. This study proposed a validation testing under research by the DFSS process that enables reproduction of vehicle level noise by component level testing using a shock absorber with the related parts, such as urethane bumper and top mount. This study also developed a compromised test matrix while analyzing the noise factors through experimental design and analysis of variance to determine what factors can affect noise. Based on this study, we expect that the vehicle level and customer claim can be validated during initial development timing by a more reliable component noise validation test.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.984-988
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• 2010

In Korea, the next generation high-speed train, whose target is maximum speed of 400km/h and operating speed of 370km/h, has been developed since 2007. In this paper, the safety of the next generation high-speed train is compared UIC 518OR under the malfunctioning situation of the suspension system. The bogie of the next generation high-speed train has two suspensions. Two different vehicle models of the next generation high-speed train are created by using VAMPIRE and ADAMS/Rail, which are specialized to design railway vehicle. And Those models are showed same dynamic properties. First of all, the sensitivity analysis of ModelCenter is performed using model of VAMPIRE. One suspension element which has significant effects on the safety are selected by result of the sensitivity analysis. And then, the dynamic analysis when the suspension element is broken is performed using ADAMS/Rail. The 30km track between Pungsegyo and Biryong tunnel in Gyeongbu High-speed Line was used at the dynamic analysis. The estimated value is found by using the normal method of UIC 518OR. The estimated values on the normal/fault state and the limit values of UIC 518OR are compared. Finally, the safety of the next generation high-speed train is verified.