• 한국철도학회논문집
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• 제14권6호
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• pp.562-568
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• 2011

철도선형에서 평면원곡선과 종곡선의 경합은 예기치 않은 주위 환경조건들에 의해 빈번히 발생하고 있으며, 이는 차량의 주행안정성, 승차감, 그리고 궤도유지보수비에 많은 영향을 끼친다. 본 연구에서는 경합부의 역학적 이론을 바탕으로 산정된 보정캔트량을 고속철도에 적용하여 궤도에 미치는 영향 및 차량의 주행안전성, 승차감을 분석하여 보정캔트의 효과에 대한 해석적 연구를 수행하였다. 그 결과 보정캔트가 있는 경우가 차량의 주행안전성 및 궤도작용력, 승차감 측면에서 모두 좋은 것으로 나타났다.

• 한국소음진동공학회논문집
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• 제27권1호
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• pp.65-71
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• 2017

This work presents a comparative work on the ride comfort of a quarter car suspension system between two different magneto-rheological (MR) dampers; one is conventional type without bypass hole and the other is featured by several bypass holes in the piston. As a first step, two different MR dampers are designed on the basis of the governing equation and manufactured with same geometric dimensions except the bypass holes. After investigating the field-dependent damping properties, two dampers are installed to the quarter car suspension system. The suspension model is then derived and a sky-hook controller is implemented to identify vibration control performance under random road. It is shown that the suspension system with MR damper featured by the bypass holes can provide much better ride quality than the case without the bypass holes. This is validated via experimental implementation.

• 한국정밀공학회지
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• 제30권10호
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• pp.1051-1059
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• 2013

In general, lateral ride comfort of railway vehicle is mainly influenced by a secondary suspension placed between the bogie and carbody. Higher operating speeds of train results in increased vibration of carbody, which has a negative impact related to the ride comfort. To solve this problem, researches to replace the conventional passive suspension with (semi)active technology in the secondary suspension of a railway vehicle have been carried out. The semi-active suspension using the magneto-rheological damper is relatively simpler system and has advantage in maintenance compared to the hydraulic type semi-active damper. This study was performed to reduce lateral vibration acceleration of carbody related to ride comfort of railway vehicles with a semi-active suspension system. The numerical analysis was conducted by replacing passive lateral damper with semi-active MR damper, and robust control with the MR damper was applied to the 1/5 scaled railway vehicle model.

• 한국정밀공학회지
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• 제18권2호
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• pp.32-39
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• 2001

• 한국기계가공학회지
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• 제16권5호
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• pp.91-98
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• 2017

This study was conducted to optimize the spring constant and the damping coefficient, which are design parameters of the tractor cabin suspension system, to minimize the ride vibration. A 3D tractor MBD (multi-body dynamics) model with a cabin suspension system was developed using a dynamic analysis program (Recurdyn). Using the developed model and optimization algorithm, the spring constant and the damping coefficient, which are the design parameters of the cabin suspension for the tractor, was were optimized so thatto minimize the maximum overshoot for the vertical displacement of the cabin was minimized. The percent maximum overshoot of the tractor cabin was simulated for the 13 initial models, which were obtained using the ISCD-II method, and for the 3 additional SAO models presented in the optimization algorithm software. The model that represents with the smallest percent maximum overshoot among the 16 models was selected as the optimized model. The percent maximum overshoot of the optimized model was about approximately 5% lower than that of the existing model.

• International Journal of Internet, Broadcasting and Communication
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• 제9권2호
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• pp.37-41
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• 2017

In the development of means of transportation, human beings who walk, ride or ride carriages are now enjoying the benefits of many means of transportation, including bicycles, airplanes, trains, buses, and cars. In the case of automobiles among various means of transportation, there is an advantage that an individual can conveniently move while possessing it. To solve air polution problems at the same time, eco-friendly automobiles such as low-noise, low-pollution, and high-efficiency automobiles have emerged. However, in the case of eco-friendly vehicleJ, engine noise at low speeds is a noise that is unlike existing vehicles and poses a threat to the safety of pedestrians. In this study, virtual engine system has been developed to prevent engine accidents caused by low- The pedestrians are aware of the fact that the vehicle is approaching.

• 제어로봇시스템학회논문지
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• 제5권8호
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• pp.907-913
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• 1999

For an automated transportation system like PRT(Personal Rapid Transit) system or IVHS, an efficient vehicle-merging algorithm is required for smooth operation of the network. For management of merging, collision avoidance between vehicles, ride comfort, and the effect on traffic should be considered. This paper proposes an unmanned vehicle-merging algorithm that consists of two procedures. First, a longitudinal control algorithm is designed to keep a safe headway between vehicles in a single lane. Secondly, 'vacant slot and ghost vehicle' concept is introduced and a decision algorithm is designed to determine the sequence of vehicles entering a converging section considering energy consumption, ride comfort, and total traffic flow. The sequencing algorithm is based on fuzzy rules and the membership functions are determined first by an intuitive method and then trained by a learning method using a neural network. The vehicle-merging algorithm is shown to be effective through simulations based on a PRT model.

• Journal of Mechanical Science and Technology
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• 제17권7호
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• pp.958-965
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• 2003

Structural integrity of either a passenger car or a light truck is one of the basic requirements for a full vehicle engineering and development program. The results of the vehicle product performance are measured in terms of ride and handling, durability, noise/vibration/harshness (NVH), crashworthiness and occupant safety. The level of performance of a vehicle directly affects the marketability, profitability and, most importantly, the future of the automobile manufacturer In this study, we used the virtual proving ground (VPG) approach for obtaining the dynamic characteristics. The VPG approach uses a nonlinear dynamic finite element code (LS-DYNA3D) which expands the application boundary outside the classic linear static assumptions. The VPG approach also uses realistic boundary conditions of tire/road surface interactions. To verify the predicted dynamic results, a single lane change test has been performed. The prediction results were compared with the experimental results, and the feasibility of the integrated CAE analysis methodology was verified.

• International Journal of Automotive Technology
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• 제6권3호
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• pp.251-257
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• 2005

Several air cells are installed in the seat cushion to adjust the stiffness of seat by changing the air pressure. To select proper air pressure in the air cells, two kinds of tests are performed. For the pressure distribution on the seat, the maximum pressure and mean pressure are compared. And for the dynamic ride values, SEAT (Seat Effective Amplitude Transmissibility) values are calculated and compared. These experiments are carried out with three different drivers, three different vehicle speeds on the highway and two different speed on the primary road, and three different air pressures. From the real car tests, optimum air cell pressure depending on the vehicle speed and driver's weight are recommended.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.47-50
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• 2011

Test Results of noise, ride comfort and vibration tests are investigated for three kinds of light rail transit vehicles which have passed the performance test and the test criteria has been satisfied. Noise level of light rail transit vehicles was 64~69dB(A) at stop and 74~75dB(A) when operated at full speed. The ride comfort index according to UIC 513R was 2.02 to 2.45. Vibration level of rubber tired light rail transit vehicle was from 'normal' to 'good' and that of iron wheel light rail transit vehicle was 'good' to 'excellent'. These data are the results for three kinds of light rail transit vehicles and more data can be accumulated after further performance test. These data can be used for a reference for the design of light rail transit vehicles.