• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.764-769
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• 2006

Vibration test on MAST(multi axial simulation table) system has several advantage over one-axial vibration test that could simulate 6-DOF, 3-axial translation and 3-axial moment, at the same time. Since field vibration motion can be fully represented with 6-DOF, multi-axial vibration test on vehicle component is widely conducted in technical leading companies to make sure its fatigue performance in vibration environment. On the way to fulfill the process, editing technique of obtained field data is key issue to success a reliable vibration testing with MAST system. Since the original signals are not only too large to fulfill it directly, but all of the measured data is not guarantee its convergency on generating its driving files, editing technique of the original signals are highly required to make some events that should meet the equal fatigue damage on the target component In this paper, key technique on editing a field data feasible for MAST system is described based on energy method in vibration fatigue. To explain its technique explicitly, author first introduced a process on field data acquisition of two vehicle component and then, representing events are produced to keep up with the editing strategy about a energy method. In the final chapter, a time information regarding a vibration test on MAST system is derived from the energy data which is critical information to perform a vibration test.

• Journal of the Korean Society for Railway
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• v.15 no.5
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• pp.436-441
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• 2012

Pressure waves are generated and propagate in tunnel when train enters a tunnel with high speed. Compression wave due to the entry of train head propagates along the tunnel and is reflected at tunnel exit as expansion wave. While expansion wave due to the entry of train tail propagates along the tunnel and is reflected at tunnel exit as compression wave. These pressure waves are repeatedly propagated and reflected at tunnel entrance and exit. Severe pressure change per second causes ear-discomfort for passengers in cabin and micro pressure wave around tunnel exit. It is necessary to analyze the transient pressure phenomena in tunnel qualitatively and quantitatively, because pressure change rate is considered as one of major design parameters for an optimal tunnel cross sectional area and the repeated fatigue force on car body. In this study, we developed the characteristics method analysis based on fixed mesh system and compared with the results of real train test. The results of simulation agreed with that of experiment.

• Journal of the Korean Society for Railway
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• v.20 no.4
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• pp.512-520
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• 2017

On a typical railway, trains travel using the friction between the wheel and the rail. Contact pressure is generated between the wheel and the rail, and the magnitude of the contact pressure changes depending on the weight, speed, wheel-set hunting, and contact point of the vehicle. In this study, the contact characteristics were analyzed through the finite element analysis for the wheel/rail system on curved track, and fatigue damage and wear rate of wheel/rail according to contact pressure were analyzed through rolling contact fatigue test. Results indicate that, general and heat treated rails showed higher wear rate than wheels, and general and heat treated rail wear rate increased rapidly over a certain number of repetitions. In addition, the general rail wear rate was about 7 ~ 15% higher than that of the heat treated rail, and a regression equation for the rail wear rate with the contact pressure in the contact pressure range of 900 ~ 1,500 MPa was presented.

• Aerospace Engineering and Technology
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• v.9 no.1
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• pp.50-59
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• 2010

In this paper, the alignment and navigation results by INGU(Inertial Navigation and Guidance Unit) onboard software and by Inertial Explorer which is a post-processing software specialized for IMU(Inertial Measurement Unit) are compared for identification of inertial sensor error models and estimation of alignment and navigation errors for KSLV-I INGU. For verification of the IMU error estimated by Kalman Filter of Inertial Explorer, the covariance parameters of inertial sensor error model state are identified by using stochastic error model of inertial sensors estimated by Allan variance and the alignment and navigation test with static condition and the land navigation test with dynamic condition are carried out. The validity of inertial sensor model for KSLV-I INGU is verified by comparison the alignment and navigation results of INGU on-board software and Inertial Explorer.

• Polymer(Korea)
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• v.29 no.1
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• pp.48-53
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• 2005

Tire wear is one of the factors that most drivers have concerned and is closely related to the tire life. It is very difficult to predict tire wear because the factors affecting tire wear seem to be very comlicated. Tire wear test should be performed at real conditions for the evaluation of tire wear. In this study, we analyze tire wear according to the severities of test courses by using the dedicated test method, more severe than real driving conditions. In order to simplify the factors affecting tire wear, we define roads’ driving severities to be driving severity numbers, DSNs which are obtained by measuring the lateral accelerations of test courses. And we compared tire wear rates and profiles with DSNs. These test results can provide the tire design guide to meet tire wear performance.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.11
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• pp.1417-1423
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• 2020

This paper proposes a waypoint guidance algorithm for the Autonomous Underwater Vehicle(AUV). The proposed simplified guidance algorithm is presented, which is combined LOS guidance and cross-track guidance for path following. Cross-track error is calculated using the position of the AUV and reference path. LOS guidance and cross-track guidance are appropriately changed according to cross-track error. And the stability of the system has been improved using variable cross-track control gain by cross-track error. Also, in this paper, navigation hardware in-the loop simulation(HILS) is implemented to verify navigation algorithm of AUV that performs combined navigation using inertial navigation device and doppler velocity log(DVL). Finally, we design integrated system HILS (including navigation HILS) for performance verification of guidance algorithm of the autonomous underwater vehicle. By comparing the sea test result with HILS result, the proposed guidance algorithm and HILS configuration were confirmed be correct.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.3
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• pp.427-432
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• 2023

In this study, MEC (: Multi-access Edge Computing) proposes a cloud service network configuration for various tests of autonomous vehicles to which V2X (: Vehicle to Everything) is applied in Wave, LTE, and 5G networks and MEC App (: Application) applied V2X service function test verification of two domains (operator (KT, SKT, LG U+), network type (Wave, LTE (including 3G), 5G)) in a specific region. In 4G networks of domestic operators (SKT, KT, LG U+ and Wave), MEC summarized the improvement effects through V2X function blocks and traffic offloading for the purpose of bringing independent network functions. And with a high level of QoS value in the V2X VNF of the 5G network, the traffic steering function scenario was demonstrated on the destination-specific traffic path.

• Journal of the Korean Institute of Gas
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• v.28 no.1
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• pp.59-64
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• 2024

In this study, we conducted research on a miniaturized transmission system suitable for ultra-compact electric vehicles, such as electric arts or small electric cars. While conventional electric vehicles eliminate multi-gear transmissions and control motor output or secure initial driving force through reducers, in vehicles like electric karts or compact electric cars, which have relatively small battery capacities, the driving range can be reduced or the motor can be stressed epending on the loading state. Therefore, in this study, we developed a low stage ratio 0.625 and high stage ratio 1.6 a two-stage transmission system that can change gears as needed, considering factors such as slope conditions and loading status, by applying the continuously variable transmission (CVT) mechanism. Based on the selected gear ratios, we designed the transmission and created a test rig to verify the power transmission efficiency of the developed transmission. Using the test rig, we varied the rotational speed and load of the transmission to confirm its power transmission characteristics and also examined the heat generation characteristics during shifting and operation. As a result, developed a two-stage transmission with a CVT structure.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.8-8
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• 2017

본 연구는 로타리 작업에 따른 105마력급 농업용 트랙터의 소요동력을 분석하기 위하여 수행되었다. 소요동력 측정 시스템은 차축 토크미터, PTO 토크미터, 주/보조 유압센서, 데이터 수집장치를 이용하여 구성하였다. 시험에 사용된 트랙터는 동양물산 105 HP급 트랙터 (S07, TYM, Korea)이며, 작업기는 로타베이터 (SW 230GL, Sungwoo Industrial Co. Ltd, Korea)를 사용하였다. 포장시험은 전라북도 부안군에 죽림길에 위치한 $4,000m^2$ ($100m{\times}40m$) 크기의 경작지 2곳에서 수행하였다. 포장시험 시 작업 단수는 주행단수 L3단 (2.38 km/h)에서 PTO 단수 1단 (540 rpm)과 2단 (750 rpm)으로 설정하였고, 로타리 작업 시 경심은 13 cm 조건에서 실시하였다. 트랙터 작업은 동양물산의 성능시험 업무를 맡고 있는 숙련된 작업자가 숙달된 방법으로 수행하였다. 포장시험지의 토양환경은 임의의 15곳에서 채취한 시료를 이용하여 토성, 함수율, 원추 관입지수에 대하여 미국 농무부 (USDA)법을 기준으로 분석하였다. 토양환경 분석 결과 토성은 Sandy loam (사양토), 평균 함수율은 35.15%, 평균 원추관입지수는 1,562 kPa로 나타났다. PTO 1단 작업 시 트랙터의 평균 소요동력은 차축, PTO, 주 유압, 보조 유압에 대하여 각각 1.8, 54.0, 1.3, 그리고 1.1 hp로 나타났다. PTO 2단 작업 시 트랙터의 평균 소요동력은 차축, PTO, 주 유압, 보조 유압에 대하여 각각 1.2, 79.4, 1.2, 그리고 1.0 hp로 나타났다. PTO 1단 작업 시 소요동력의 합은 58.2 hp로, 정격 마력 (105 hp) 대비 55.43 % 사용한 것으로 나타났으며, PTO 2단 작업 시 소요동력의 합은 82.8 hp로, 정격 마력 대비 78.85% 사용한 것으로 나타났다. PTO 1단 대비 2단에서는 PTO를 제외한 차축, 주 유압, 보조 유압의 소요동력이 감소하였으나, PTO에서 약 1.47배로 크게 증가하여 전체적으로 소요동력이 증가한 것으로 나타났다. 향후 다양한 작업기 및 작업 단수에 따른 소요동력을 분석하여 농업용 트랙터의 모든 부하 조건에 대한 데이터베이스 구축에 관한 연구를 수행할 예정이다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.10
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• pp.3911-3916
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• 2010

In this paper we describe contents and results on running test for ATP on-board equipment, which has propelled as one of the research projects, so called, "Reliability assessment and operation technology development for Korean-type tilting trains" in order to ensure the safety and operation efficiency of tilting trains. We developed tilting trains for the speed-up of conventional lines and for the passenger service improvement where the KTX is not available. And we made progress the operation trial test in the 120,000 km distance with the use of ATS equipment, used in existing lines, for the purpose of the reliability assessment of the developed tilting trains. We decided to accelerate the speed for more than 200km/h with respect to the 6 existing lines including Jungang-line and Chungbuk-line where KTX has not operated. According to this decision, Train control system is to be changed from ATS to ATP. We should have installed an ATP on-board unit in tilting trains and verified the operational suitability, therefore we installed the same ATP on-board unit on tilting trains as that used in the ATP construction project on Gyeongbu-line and Honam-line, and verified that the function and performance of the installed ATP on-board unit conformed to the tilting trains operation.