• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1996.03a
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• pp.194-199
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• 1996

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.380-386
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• 2008

The development of a new railway vehicle is under progress through the Next Generation High-Speed Rail Development Project in Korea. Its aim is to develope fundamental technology of the vehicle that can run over 400km/h. The new distributed traction bogie system, 'HEMU'(High-speed Electric Multiple Unit), will be used and is different from that of previously developed high speed railway vehicles. Previous vehicles adopted push-pull type system, which means one traction-car drives rest all of the vehicle. Due to the difference, investigation on dynamic behavior and its safety evaluation are necessary, as a part of verification of the design specification. In the paper, current progresses of researches are presented. And the High-Speed Railway vehicle system is evaluated for a dynamic characteristic simulation. Proper dynamic models including air-suspension system, wheel-rail, bogie and car-body is developed according to the vehicle simulation scenario. The basic platform for the development of dynamic solver is prepared using nodal, modal coordinate system and wheel-rail contact module. Operating scenario is prepared using commercial dynamic analysis program and used for development of dynamic model, which contains many parts such as carbodies, bogies and suspension systems. Furthermore, international safety standard is applied for final verification of the system. Finally, the reliability of the dynamic model will be verified with test results in the further researches. This research will propose a better solution when test results shows a problem in the parts and elements. Finally, the vehicle that has excellent performance will be developed, promoting academic achievement and technical development.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1095-1098
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• 2005

Most electronic chassis control systems until today have been designed with optimization on its own performance. However, According to the increase of the interest regarding a vehicle safety and development of information technique, the integration technique of current chassis systems is being emphasized. Each enterprise proposed it with name of GCC(Global Chassis Control) or UCC(Unified Chassis Control). This study realizes control algorithm of suspension and brake by using the vehicle model of low degree of freedom as the primary stage of realization of integrated chassis control system. The proposed algorithm build the simulation environment connected to the CarSim having full vehicle model of 27 degree of freedom for raising the thrust of results

• International Journal of Automotive Technology
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• v.8 no.3
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• pp.309-317
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• 2007

In this study, we conducted a vibration fatigue analysis of the lower control arm in a vehicle suspension system. The vehicle was driven during the tests so that the dynamic effects could be taken into account. The dynamic load of the frequency domain was superimposed on the frequency response analysis. We performed a virtual proving ground test using multi-body dynamics, along with a finite element analysis and fatigue life predictions. Shape optimization was also considered using the design of the experimental approach, and a response surface analysis was performed to improve the durability performance of the lower control arm. We identified the elements that had the most influence on the optimal shape of the finite element model and analyzed the sensitivity of those elements. Then the optimal points that minimized the amount of damage to the areas of interest were determined through a response surface analysis. The results suggested that the fatigue life of the model increased as its mass was not increased excessively, and demonstrated that these design procedures yielded an appropriate optimized lower control arm model.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.23 no.4
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• pp.403-407
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• 2014

To use vibration energy to generate electricity, a resonance vertical linear electric generator was applied to the suspension of a vehicle in a previous paper. However, the working conditions, including mass change in the vehicle body related to the cargo on board, number of passengers and the temperature difference caused by the operating environment, can influence the permanent magnet, which is the main component of the electric generator. Therefore, a robust optimum design is required to minimize the influences from the diverse operation conditions and maximize the electromotive force of the electric generator. In this paper, a resonance linear electric generator is introduced. Vibration response analysis to find the input velocity of the electric generator and an electromagnetic transient analysis to apply changes in the performance of the permanent magnet are performed. Finally, the optimum value of each design variable is derived using a Taguchi method.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.6
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• pp.633-641
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• 2015

The ROM (roll over mitigation) system is a next-generation suspension system that can improve vehicle-driving stability and ride comfort. Currently, mass-produced safety systems, such as ESC (electronic stability control) and ECS (electronic control suspension), enable measurements of longitudinal and lateral acceleration as well as yaw rate through inertial sensor clusters, but they lack direct measurements of the roll angle. Therefore, in this paper, a roll angle estimation algorithm from ESC system sensors and tire normal force has been proposed. Furthermore, this study presents a method for roll over mitigation force distribution between the front and rear of a ROM system. Performance and reliability of the roll angle estimation and roll over mitigation force distribution were investigated through simulations. The simulation results showed that the proposed control algorithm and strategy are reliable during vehicle rollovers.

• Journal of Drive and Control
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• v.18 no.2
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• pp.38-45
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• 2021

In recent years, the demand for an onboard scale system which can directly monitor load distribution and overload of vehicles has increased. Depending on the suspension type of the vehicle, the onboard scale system could use different types of sensors, such as, angle sensors, pressure sensors, load cells, etc. In the case of a vehicle equipped with leaf spring suspension system, the load of the vehicle is measured by using the deflection or displacement of the leaf spring. Leaf springs have hysteresis characteristics that vary in displacement depending on the load state. These characteristics cause load measurement errors when moving or removing cargoes. Therefore, this study aimed at developing an onboard scale device for cargo vehicles equipped with leaf springs. A sectional modeling method which can reduce measurement errors caused by hysteresis characteristics was also proposed.

• Journal of the Korea Society of Computer and Information
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• v.12 no.3
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• pp.287-293
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• 2007

This paper proposed modelling and design method in suspension system design to analyze active suspension equipment by adopting intelligent robust control theory. Recent in the field of suspension system design it is general to adopt active control scheme for stiffness and damping, and connection with other vehicle stability control equipment is also intricate, it is required for control system scheme to design more robust, higher response and precision control equipment. It is known that active suspension system is better than passive spring-damper system in designing suspension equipment. We analyze suspension system with considering location of front-rear wheel and driving velocity, then design robust control system. Numerical example is shown for validity of intelligent control system design in active suspension system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.160-166
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• 2018

This paper proposes an advanced suspension system and reports its performance in the framework of the preview control algorithm based on the RPS (road profile sensing) system and MSD system with the multi-stage damping characteristics. Typical disturbance inputs that cause excessive vibration and steering instability of an automobile are irregular obstacles that protrude or sink into the road surface to be driven. The control performance can be improved if information on the existence and shape function of its obstacle is known. Based on the results of the previous study, advanced research that uses the actuating system has been processed to be commercialized practically. For this purpose, a switching algorithm between the control logic and the multi-stage damping system was developed and its connectivity is presented. To verify the applicability of an actual vehicle, the proposed control system was implemented in full vehicle models and simulations were performed. The proposed system using the 3-DS actuator system, which is applied for structural simplicity, can improve the ride comfort and steering stability. In addition, the results indicate the feasibility of the intelligently controlled suspension system.

• International Journal of Railway
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• v.2 no.3
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• pp.118-123
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• 2009

Railway track alignment Standards set a minimum lenght value for straight and circular alignments (art. 5.2.9.), in order to ensure passenger ride comfort in railway vehicles of which dynamic oscillations will thus have to be limited. The transitions between alignments can cause abrupt changes (usually called discontinuities or singular points of the alignment) of curvature, of rate of change of curvature or of rate of change of cant. A passenger is likely to experience effects due to the excitation of the elastic suspension of the vehicle which generates oscillations that are damped as the vehicle moves away from the singularity. The amplitude of these oscillations should be adequately attenuated by the damping of the suspension system within the interval between two successive singular points, especially to avoid resonances. Therefore minimum lengths between two successive singular points are stated in alignment standards. Nevertheless, these nonnative values can be overly conservative in some cases. As an alternative, track alignment designers could try to assess how much the excitation has been attenuated between two successive singular points and thus assess at which point a new singularity may be present without affecting ride comfort. Although such assessment can be made with commercial SW packages which simulate the dynamic behavior of a vehicle considered as a set of rigid bodies interconnected with elastic elements simulating the suspension systems (such as SIMPACK, ADAMS or VAMPIRE), a simplified and user-friendly computation method (based upon the analytical solution of differential equations governing the phenomenon) is made available in this paper to track design engineers, not always used to working with full dynamic models.