• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1721-1726
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• 2004

The studies of the half active suspension have been performed using various suspension models. In the early days, the modeling considered the inputs to the active suspension as the linear forces. Recently, due to the development of new control theory, the forces input to the half car active suspension system has been replaced by an actual input to the hydraulic actuators. Therefore, the dynamic of the active suspension system now consists of the dynamic of half car suspension system plus the dynamic of the hydraulic actuators. This paper proposed a new modeling technique in integrating both dynamic models. The proportional integral sliding mode control technique is utilized to control the hydraulically actuated of the half car active suspension system. The performance of the half car hydraulically actuated active suspension system is simulated with a bump input. The results show that the proposed modeling technique and the proportional integral sliding mode controller are improved the ride comfort and ride handling of the half car active suspension system.

• 연구논문집
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• s.27
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• pp.35-45
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• 1997

The dynamic design process for the articulated bogie of light rail vehicle(LRV) was studied to design a primary and secondary suspension elements. Suspension stiffness and damping is selected on the basis of the ride quality and suspension stroke trade-off. LRV was modeled as a 2 d.o.f linear system for the design of vertical suspension characteristics and a 4 d.o.f linear system for the design of lateral suspension characteristics. FRA's class-4-track irregularity was used for the exciting disturbance on track. The optimum value of primary and secondary suspension characteristics was determined using this design process.

• Advances in Automotive Engineering
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• v.1 no.1
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• pp.1-20
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• 2018

The aim of this study is the optimization of the parameters of interconnected Hydro-Pneumatic (HP) suspension system of a three-axle vehicle for ride comfort and handling. For HP suspension systems of equivalent vertical stiffness and damping characteristics, interconnected HP suspension systems increase roll and pitch stiffness and damping characteristics of the vehicle as compared to unconnected HP suspension systems. Thus, they result in improved handling and braking/acceleration performances of the vehicle. However, increased roll and pitch stiffness and damping characteristics also increase roll and pitch accelerations, which in turn result in degraded ride comfort performance. Therefore, in order to improve both ride comfort and vehicle handling performances simultaneously, an optimum parameter set of an interconnected HP suspension system is obtained through an optimization procedure. The objective function is formed as the sum of the weighted vertical accelerations according to ISO 2631. The roll angle, one of the important measures of vehicle handling and driving safety, is imposed as a constraint in the optimization study. Upper and lower parameter bounds are used in the optimization in order to get a physically realizable parameter set. Optimization procedure is implemented for a three-axle vehicle with unconnected and interconnected suspension systems separately. Optimization results show that interconnected HP suspension system results in improvements in both ride comfort and vehicle handling performance, as compared to the unconnected suspension system. As a result, interconnected HP suspension systems present a solution to the conflict between ride comfort and vehicle handling which is present in unconnected suspension systems.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.5
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• pp.146-153
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• 2004

Torsion beam rear suspension has been widely adopted to the rear suspension of vehicle by reason of simple structure and cost competitiveness. Since the kinematic characteristics of torsion beam rear suspension are determined by elastic behavior of torsion beam, quasi-static analysis based on finite element modeling of torsion beam has been conducted to obtain the kinematic parameters of torsion beam rear suspension. In this paper, simple kinematic equations with rear geometric parameters are derived to predict the kinematic behavior of torsion beam rear suspension. The suspension design parameters such as roll center height, roll stiffness, roll steer and roll camber can be easily obtained with the kinematic equations. The suggested kinematic equations are validated from comparison with the test results and solution offered by ADAMS. The suspension design parameters varied with the position of torsion beam are discussed.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.811-815
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• 2005

Traditional passive suspension has limitations to meet the required specifications of high level trains, and so Active suspension system is proposed to meet the requirements with active components which could be controlled by external signal for optimized behavior of train. Active suspension is to be divided by Full active suspension and Semi-active suspension whether using the external power source or not, and though the performance of Semi-Active suspension is worse than Full one. Semi-active suspension is focused with its effectiveness per cost. Semi-Active suspension system consists of sensors, ECU (electrical control unit), and variable damper, which are to be designed to be fit for train system. And the software of ECU is to be developed for to be suited to its dynamic behavior through simulation result calculated by proven model. In this experimental study, the hardware and software of semi-active suspension system is to be realized and its performance for improvement of ride quality to be confirmed through roller rig test.

• KSTLE International Journal
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• v.7 no.1
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• pp.1-4
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• 2006

The electro rheological behavior of the hollow polyaniline pimelate suspension in silicone oil was investigated. Hollow polyaniline pimelate suspension showed a typical ER response (Bingham flow behavior) upon application of an electric field. The shear stress for the suspension exhibited the dependence with a factor equals to 0.84 power on the electric field. The experimental results for the hollow polyaniline pimelate suspension correlated with the conduction models of Tang et al., and this suspension behaved as an ER fluid.

• Wind and Structures
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• v.10 no.6
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• pp.533-542
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• 2007

The cable-stayed-suspension hybrid bridge is a cooperative system of the cable-stayed bridge and suspension bridge, and takes some advantages and also makes up some deficiencies of both the two bridge systems, and therefore becomes strong in spanning. By taking the cable-stayed-suspension hybrid bridge, suspension bridge and cable-stayed bridge with main span of 1400 m as examples, the mechanics performance including the static and dynamic characteristics, the aerostatic and aerodynamic stability etc is investigated by 3D nonlinear analysis. The results show that as compared to the suspension bridge and cable-stayed bridge, the cable-stayed-suspension hybrid bridge has greater structural stiffness, less internal forces and better wind stability, and is favorable to be used in super long-span bridges.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.771-776
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• 2002

Optimal shape of the NFR suspension is studied and developed to improve the dynamic performance and reduce the vibration of the suspension system including a optical head slider. Since accurate position control and stability of the slider motion are highly required in NFR due to the narrower track width and the heavier slider than HDD slider with the low flying height, the dynamic characteristics of the suspension are very important to the mechanical performance of the system. The first natural frequencies in flexural and lateral motion of the suspension are critical factors affecting the dynamics and stability of the flying head, so that the dynamic parameters should be designed properly to avoid an excessive vibration or a crash of the slider on the disk. This paper optimizes the shape of the suspension based on homogenization method in NASTRAN and develops a new suspension shape for NFR system. The suspension is tested on experiment to verify the improvement of the dynamic characteristics.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.5
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• pp.514-520
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• 2015

The effects of suspension stiffness on the reaction load of the gearbox suspension for a three-point suspension wind turbine drive train were investigated by finite element analysis. The reaction forces of the gearbox suspension appear to increase as the gearbox suspension stiffness increases; however, the main bearing stiffness has a reverse effect on the reaction forces. The influence of the gearbox suspension stiffness is greater than that of the main bearing. Since the suspensions must provide the gearbox with proper support, it is not practical to use soft gearbox suspension for small reaction forces. It is more feasible to use stiff main bearings. As a guideline for the main bearing stiffness in the present study, we propose a relative stiffness of 100-150% of the reference.

• Wind and Structures
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• v.14 no.3
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• pp.209-220
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• 2011

The cable system is generally considered to be a structural solution to increase the spanning capacity of suspension bridges. In this work, based on the Runyang Bridge over the Yangtze River, three case suspension bridges with different 3D cable systems are designed, structural dynamic characteristics, the aerostatic and aerodynamic stability are investigated numerically by 3D nonlinear aerostatic and aerodynamic analysis, and the cable system favorable to improve the wind-induced instability of long-span suspension bridges is also proposed. The results show that as compared to the example bridge with parallel cable system, the suspension bridge with inward-inclined cable system has greater lateral bending and tensional frequencies, and also better aerodynamic stability; as for the suspension bridge with outward-inclined cable system, it has less lateral bending and tensional frequencies, and but better aerostatic stability; however the suspension bridge is more prone to aerodynamic instability, and therefore considering the whole wind-induced instability, the parallel and inward-inclined cable systems are both favorable for long-span suspension bridges.