• Journal of Korean Society of Steel Construction
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• v.17 no.3 s.76
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• pp.263-270
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• 2005

This paper presents a program for protecting vehicles against side winds on highways. The present study consists of three processes. The first one involves giving a guideline for evaluating driving safety in high winds. The second one involves making a guideline for determining the necessity of wind protection system for a certain road area. A reasonable procedure is suggested based on the probability model of wind data on weather stations and the correction of local topographical conditions. The third one involves design of wind barriers. Both CFD analyses and wind tunnel tests were performed to find the proper type of wind barrier considering vehicle controllability, structural safety, economical efficiency as well as driver's visibility. Performance of the designed wind fences was verified from field tests. The performance of the four different types of wind barrier installed at the elevated bridge were tested and some of the results were provided.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.9
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• pp.643-651
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• 2020

A capsule train runs inside a sub-vacuum tube and can reach very high speed due to the low air resistance. A capsule train uses a superconducting electrodynamic suspension (SC-EDS) method for levitation, which allows for a large levitation gap and does not require gap control. However, SC-EDS has inherent characteristics such as the large gap variation and a small damping effect in the levitation force, which can degrade the running stability and ride comfort. To overcome this, a stability improvement device should be designed and applied based on dynamic analysis. In this study, a 1/10 small-scale testbed was developed to replicate the dynamic characteristics of a capsule train and investigate the performance of stability improvement devices. The testbed is composed of a 6-degree-of-freedom Stewart platform for the realization of bogie motion, a secondary suspension with a running stabilization device, and a carbody. Based on the dynamic similarity law proposed by Jaschinski, the small-scale testbed was manufactured, and a bogie motion algorithm was applied with the consideration of guideway irregularity and levitation stiffness. The experimental results from the testbed were compared with simulation results to investigate the performance of the testbed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.4
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• pp.752-757
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• 2008

In this paper, studied Measuring Equipment for Brake Test provided to test a braking distance and stability on various conditions while at stop/drive. It ensures an objectivity, repeatability and reproducibility for a brake test, which may be applied to various types of braking distance and stability tests anywhere in the world. With Measuring S/W for Brake Test mounted on the vehicle while at stop/drive, braking distance and stability were examined under conditions specified of NCAP and vehicle manufactures A and B's own test, which was available under all conditions and even harder ones to confirm this measuring S/W for brake test be applicable for any changed conditions for the future.

• Nuclear Engineering and Technology
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• v.27 no.5
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• pp.661-669
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• 1995

A mobile robot, named KAEROT, has been developed for inspection and maintenance operations in nuclear facilities. The main feature of locomotion system is the planetary wheel assembly with small wheels. This mechanism has been designed to be able to go over the stairs and obstacles with stability. This paper presents the inverse kinematic solution that is to be operated by remote control. The automatic stair climbing algorithm is also proposed. The. proposed algorithms generates the moving pathes of small wheels and calculates the angular velocity of 3 actuation wheels. The results of simulations and experiments are given for KAEROT peformed on the irregular stairs in laboratory. It is shown that the proposed algorithm provides the lower inclination angle of the robot body and increases its stability during navigation.

• Journal of Institute of Control, Robotics and Systems
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• v.4 no.6
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• pp.772-779
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• 1998

본 논문에서는 강인한 비선형 예측제어기를 개발하여 연구용 원자로 벽면검사를 위한 수중로봇에 적용하여 보았다. 비선형 예측제어기는 먼저 적절한 함수 확장을 이용하여 시스템의 미래 출력 값을 예측하고, 예측값과 설정치와의 차이를 최소화시키는 제어입력을 구하여 시스템에 인가한다. 이러한 제어기에 의한 폐회로 동특성은 목적함수가 상태변수로 이루어진 경우는 항상 안정한 특성을 보이고 목적함수가 출력변수으로 이루어진 경우는 상대 계수가 4이하인 경우에 안정한 특성을 보인다. 이 제어기는 기존의 비선형 제어기가 적용 불가능한 시스템에도 적용 가능한 장점을 가지고 있다. 시스템의 불확실성이 큰 경우, 제어 안정도 및 제어 성능을 향상시키기 위하여 감독제어를 비선형 예측제어기에 포함시켰다. 이러한 제어기를 수중 벽면 주행로봇에 대한 모사실험에 적용한 결과 제어기의 강인함과 제어 성능 향상을 볼 수 있었다.

• Journal of Korean Society of Forest Science
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• v.104 no.1
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• pp.98-103
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• 2015

This study was conducted to analyze the running stability of a semi-crawler type mini-forwarder. The running stability analysis was performed by using a dynamic analysis program, RecurDyn. Physical properties of the semi-crawler type mini-forwarder was performed by using 3D CAD modeler, AutoCAD 3D. As a result from the computer simulation of stationary sideways overturning, it was found that the semi-crawler type mini-forwarder runs safely on a road with a slope not bigger than $20^{\circ}$ regardless whether it is empty or loaded, but in case of a road with a slope bigger than $20^{\circ}$, it is assumed that it is difficult for the car to run safely due to some dangers. In addition, it was found that the critical slope of its sideways overturning gets much smaller when empty since the location of its gravity center is elevated and much higher when it is loaded. As a result from the computer simulation of its hill-climbing ability, since the running speed is unstable in case of a road with a vertical slope not smaller than $28^{\circ}$, it is assumed that it is safe to drive it on a road with a slope not bigger than $28^{\circ}$. Taking a look at the result from an analysis of the running safety when it passes an obstacle, it was observed that a front tire comes off the ground when the running speed of the car is 5 and 4 km per hour respectively when it is empty and loaded while the gravity center of the front tire is watched. When taking a look at the changes in the location of the gravity center of the rear wheel crawler shaft, it was not found that the shaft comes off the ground at the test speeds both when it is empty and loaded.

• Journal of Auto-vehicle Safety Association
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• v.15 no.2
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• pp.6-12
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• 2023

For the commercialization and standardization of autonomous vehicles, demand for rigorous safety criteria has been increased over the world. In Korea, the number of extraordinary service permission for automated vehicles has risen since Hyundai Motor Company got its initial license in March 2016. Nevertheless, licensing standards and evaluation factors are still insufficient for operating on public roadways. To assure driving safety, it is significant to verify whether or not the vehicle's decision is similar to human driving. This paper validates the safety of the autonomous vehicle by drawing scenario-based comparisons between manual driving and autonomous driving. In consideration of real traffic situations and safety priority, seven scenarios were chosen and classified into basic and advanced scenarios. All scenarios and safety factors are constructed based on existing ADAS requirements and investigated via a computer simulation and actual experiment. The input data was collected by an experimental vehicle test on the SNU FMTC test track located at Siheung. Then the offline simulation was conducted to verify the output was appropriate and comparable to the manual driving data.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.2
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• pp.122-134
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• 2020

To improve traffic congestion, reduce fuel consumption, and improve the stability of truck operations, truck platooning, in which several trucks are organized in a single platoon, is being actively researched globally. Compared to the operation of a single truck, the operation of a truck platoon requires more caution before the actual operation because an accident of one vehicle in the platoon can lead to an accident with all the vehicles in the platoon. Therefore, this study examined the types of trucks and cargo suitable for truck platooning to prevent safety accidents. The review showed that a closed-van-type truck is appropriate for truck platooning to prevent falling objects during driving. In the case of cargo types, it is necessary to exclude liquids and dangerous goods defined in related laws from truck platooning.

• Journal of the Korean Society for Railway
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• v.7 no.4
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• pp.367-373
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• 2004

The investigation of running stability of the train for curved track is necessary in view of preventing the train from derailment caused by unbalanced forces transferred from the wheel and guaranteeing moderate level of running safety in curve sections. This paper carried out an analysis of running stability of tilting trains in conventional line which the test operation of tilting trains under development are scheduled. For this purpose, the wheel load and lateral pressure to the rail are evaluated. The criteria for the calculated wheel load and derailment coefficient are compared to the design criteria for running stability. It is founded that the running stability of tilting trains for curved track is guaranteed to have sufficient safety and the train speed in curve is governed by the geometric layout of track rather than the criteria for running stability.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.57-60
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• 2004

A domestic's freight stock is about 14,000 cars. Most of them is consisted of casting bogie type. Casting bogie type has some problems such as maintenance, part abrasion, running safety etc. Now a day casting bogie type have replaced with welded type bogie for high speed. The maximum speed of the container freight car is 70km/h limit at empty weight condition in case of casting type bogie frame. So there are some difficulty in commercial service for high speed coaches. Then we should re-decide whether the casting bogie type has speed up 90km/h limit at empty weight through out the vibration characteristic.