• Journal of Applied Reliability
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• v.12 no.2
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• pp.91-103
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• 2012

Tubular markers for road safety facilities are used to lead the driver's sight line and separate the lanes on the road. Such tubular markers are usually installed on the road and frequently hit by vehicles, they are accordingly requested to assure the product durability. The traditional evaluation method of tubular markers include only quality tests of the material properties. However, most of consuming agencies in charge of road management at fields have proposed problems on long-term performance of the products hit by vehicles under various weather conditions. Therefore, the objectives of this study are to develop the reliability test methods and equipments to simulate the product failures of tubular markers due to vehicle collision and wheel compression and the delamination and discoloration of reflection sheets attached on the surface of the products under high and low temperatures.

• Journal of Auto-vehicle Safety Association
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• v.12 no.3
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• pp.34-42
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• 2020

ADAS (Advanced Driver Assistance Systems) uses sensors such as camera, radar, lidar and GPS (Global Positioning System). Among these sensors, the camera has many advantages compared with other sensors. The reason is that it is cheap, easy to use and can identify objects. In this paper, therefore, a theoretical formula was proposed to obtain the distance from the vehicle's front wheel to the lane using a monocular camera. And the validity of the theoretical formula was verified through the actual vehicle test. The results of the actual vehicle test in scenario 4 resulted in a maximum error of 0.21 m. The reason is that it is difficult to detect the lane in the curved road, and it is judged that errors occurred due to the occurrence of significant yaw rates. The maximum error occurred in curve road condition, but the error decreased after lane return. Therefore, the proposed theoretical formula makes it possible to assess the safety of the LKA system.

• International Journal of Railway
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• v.3 no.3
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• pp.90-94
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• 2010

In this paper, driving functions of the Korea High-speed Trains were decomposed based on systems engineering architecture. In order to analyze the driving function, various systems engineering tools and methods were used. Moreover, interfaces of decomposed driving functions were analyzed to figure out purposes of the driving functions. Through activity modeling of driving function of the Korea High-Speed Trains, main functions were derived when starting, speeding and stopping. When the high speed train is speeding, pre-departure checks and wheel slide prevention are essential driving activities for the safety and when the high speed train runs high speed, maintaining driving stability by monitoring bogie hunting and monitoring drivers' safe operation by vigilance systems is important. Furthermore, when the train is braking, the driver should checks brake and suspensions as safety actions.

• Korean Journal of Agricultural Science
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• v.43 no.4
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• pp.650-655
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• 2016

Gears are components of transmission which transmit the power of an engine to a machine and offer numerous speed ratios, a compact structure, and high efficiency of power transmission. Gear train design in the automotive industry uses simulation software. However, PTO (Power Take-Off) gear design for agricultural applications uses the empirical method because of the wide range of load fluctuations in agricultural fields. The PTO is an important part of agricultural tractors which transmits the power to various tractor implements. Therefore, a simulation was essential to the optimal design of the PTO. When the PTO gear is optimally designed, there are many advantages such as low cost, reduced size, and light weight. In this study, we conducted the bending and contact safety factor simulation for the PTO gear of an agricultural tractor. The bending and contact safety factors were calculated on ISO 6336 : 2006 by decreasing the face widths of the PTO pinion and wheel gear from 18 mm at an interval of 1 mm. The safety factor of the PTO gear decreased as the face width decreased. The contact safety factors of the pinion and wheel gear were 1.45 and 1.53, respectively, when the face width was 18 mm. The simulation results showed that the face width of the PTO gear should be greater than 9 mm to maintain the bending and contact safety factors higher than 1. It would be possible to reduce the weight of the PTO gear for different uses and working conditions. This study suggests that the possibility of designing an optimal PTO gear decreases as its face width decreases.

• Journal of the Korean Society for Railway
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• v.12 no.6
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• pp.859-864
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• 2009

When the vehicle passes through turnout, the design is required to minimize the change of lateral force. Therefore, in case the vehicle passed the through turnout, we ought to execute dynamic analysis of the interaction between the vehicle and turnout in order to make an estimate of the lateral force and the derailment coefficient on the turnout. In this paper, we established the analytical model of the vehicle and turnout and analysed running safety when the vehicle passes through turnout in order to improve running safety of the vehicle on turnout. Also, to verify the vehicle and turnout model, we analysed reaction force and running behavior between wheel and rail, and running safety of the vehicle by changing cradle part and the tongue rail when the vehicle passes through turnout.

• Structural Engineering and Mechanics
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• v.59 no.4
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• pp.683-701
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• 2016

Safety is the prime concern for a high-speed railway bridge, especially when it is subjected to a collision. In this paper, an analysis framework for the dynamic responses of train-bridge systems under collision load is established. A multi-body dynamics model is employed to represent the moving vehicle, the modal decomposition method is adopted to describe the bridge structure, and the time history of a collision load is used as the external load on the train-bridge system. A (180+216+180) m continuous steel trussed-arch bridge is considered as an illustrative case study. With the vessel collision acting on the pier, the displacements and accelerations at the pier-top and the mid-span of the bridge are calculated when a CRH2 high-speed train running through the bridge, and the influence of bridge vibration on the running safety indices of the train, including derailment factors, offload factors and lateral wheel/rail forces, are analyzed. The results demonstrate that under the vessel collision load, the dynamic responses of the bridge are greatly enlarged, threatening the running safety of high-speed train on the bridge, which is affected by both the collision intensity and the train speed.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.89.4-89
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• 2001

We propose an electric wheelchair that is suitable for the upper-limbs disabled with sufficient operability and low expenses. Features of this wheelchair, 1) By instating a simple mechanical module, existing electric wheelchairs can be readily converted to a special version for the upper-limbs disabled. 2) The electric wheelchair can be freely operated by motion of a head. 3) A vision system to assure safety operation by the disabled is introduced.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.1073-1074
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• 2009

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.731-735
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• 1990

The mobile robot, named as KAEROT, is designed to go up and down stairs in nuclear facilities. To get a proper stable motion, kinematic modeling and analysis are seriously considered and new climbing algorithm is proposed focused on the stability. A couple of small wheels of one planetary wheel have to contact the surface ol stairs all the time to give the guarantee for stability and safety. To confirm the validity of the proposed algorithm, simulation is carried out. The results make evident of feasibility for the algorithm.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.1264-1269
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• 2006

Measurement and estimation of rail irregularity is an important factor to concern travelling safety of train. Now a day, rail irregularity have been measured by EM120 and ROGER 1000K imported from MERMAC Co. Italy and making researches actively in Korea. This paper mainly consider to find correlation between acceleration value of wheel axle in HSR350x and rail irregularity value measured by EM120.