• 한국CDE학회논문집
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• 제19권4호
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• pp.332-339
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• 2014

This paper presents on the development of wheel-terrain interaction device using low-priced sensors, which will be used to predict the drawbar pull and optimal slip of off-road vehicle in real time. The essential variables obtained in the device to predict the mobility of vehicles are determined based on semi-empirical model describing the wheel-terrain interaction. Using the developed device, the experiments about the wheel-terrain interaction were performed on the soil of the Jumunjin standard sand, which yielded dynamic weight, motor driving torque, drawbar pull, and sinkage with respect to wheel slip ratio. Finally, the repeatability of the measured data are verified through repeating the experiments three times on the same condition.

• 한국군사과학기술학회지
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• 제13권5호
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• pp.894-902
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• 2010

This paper presents a vision-based robust off-road terrain classification method against environmental variation. As a supervised classification algorithm, we applied a neural network classifier using wavelet features extracted from wavelet transform of an image. In order to get over an effect of overall image feature variation, we adopted environment sensors and gathered the training parameters database according to environmental conditions. The robust terrain classification algorithm against environmental variation was implemented by choosing an optimal parameter using environmental information. The proposed algorithm was embedded on a processor board under the VxWorks real-time operating system. The processor board is containing four 1GHz 7448 PowerPC CPUs. In order to implement an optimal software architecture on which a distributed parallel processing is possible, we measured and analyzed the data delivery time between the CPUs. And the performance of the present algorithm was verified, comparing classification results using the real off-road images acquired under various environmental conditions in conformity with applied classifiers and features. Experiments show the robustness of the classification results on any environmental condition.

• 한국안전학회지
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• 제32권6호
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• pp.143-149
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• 2017

According to traffic accidents statistics, the number of fatalities, injuries and the rate of increase of traffic accidents have been decreasing over last 5-years. The fatality rate is 1.9 for total accidents but the fatality rate for single vehicle accidents shows a 7.9, which is 4 times greater than the average for all accidents. Single vehicle accidents, usually occur as a vehicle impacts a fixed objects on the roadside as the vehicle runs-off from the road. However, few researches have been conducted considering the accident severity of single vehicle accidents which impact to the fixed objects on the road. The single vehicle accident is directly related to the composition of road cross section, (since it is the required the minimum width of a road for all run-off-the-road vehicles to recover or come to a safe stop). Therefore, this study analyzes the influence of road cross section on traffic accidents to find out the severity of single vehicle accident. To analyze the road elements which are related to the accident severity, the Ordered Probit Model was used. As variables, the element of road cross section such as the radius(m), vertical curve(%), cross sectional grade(%), road width(m). number of climbing lane, median, and curb, were used (as was the 3-years of accidents data). This study found out that cross slope(%), road width(m), and the number of climbing lane are related to the severity of accident. The result of this study could be expected to improve the road safety and to be used as the base data for further road safety research.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.780-785
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• 2003

Maintaining track tension in tracked vehicles minimizes the excessive load on the tracks and prevents the peal-off of tracks from the road-wheel, and adequately guarantees the stable and improved driving of the tracked vehicles. However, the track tension cannot be easily measured due to the limitation in the sensor technology, harsh environment, etc. In this study, the track tension is estimated in real-time from the measurable signals of tracked vehicles and controlled based on a fuzzy logic controller. The proposed control system is implemented on tracked vehicles and its performance is evaluated under various driving conditions.

• Journal of Advanced Marine Engineering and Technology
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• 제25권6호
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• pp.1203-1210
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• 2001

This study was carried out to develop an engine for off-road vehicles especially for farm tractors using the liquefied petroleum gas (LPG) which is known as a source of energy having good potential of substitute fuel for diesel engine because of its economical advantage and low pollutant materials after combustion. The study was focused on develop an engine of high in specific power output, low in specific fuel consumption and emission of pollutants. A series of teat was dope on the engine - various laboratory tests to analyze performance of the engine and actual field tests with the engine installed on a farm tractor as a power source.

• 제어로봇시스템학회논문지
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• 제17권4호
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• pp.313-320
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• 2011

Multi-axle driving vehicles that are used in special environments require high driving performance, steering performance, and stability. Among these vehicles, 6WS/6WD vehicles with middle wheels have structural safety by distributing the load and reducing the pitch angle during rapid acceleration and braking. 6WS/6WD vehicles are favored for military use in off road operations because of their high maneuverability and mobility on extreme terrains and obstacles. 6WD vehicles that using in-wheel motor can generate the independent wheel torque without other mechanical parts. Conventional vehicles, however, cannot generate an opposite driving force at each side wheel. Using an independent steering and driving system, six-wheel vehicles can show better performance than conventional vehicles. Using of independent steering and driving system, the 6 wheel vehicle can improve a performance better than conventional vehicle. This vehicle enhances the maneuverability under low speed and the stability at high speed. This paper describes an independent 6WS/6WD vehicle, consists of three parts; Vehicle Model, Control Algorithm for 6WS/6WD and Simulation. First, vehicle model is application of TruckSim software for 6WS and 6WD. Second, control algorithm describes the optimum tire force distribution method in view of energy saving. Last is simulation and verification.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 춘계학술대회 논문집 센서 박막재료연구회 및 광주 전남지부
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• pp.6-9
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• 2008

A 3D depth measurement system is proposed for mobile vehicles. Depth measurement system which is composed of a rotating mirror, a line laser and mono-camera is employed to detect depth, where the laser light is reflected by the mirror and projected to- the scene objects whose locations are to be determined. The obtained depth information is converted into an image. Such depth images of the road region represent even and plane while that of off-road region is irregular or textured. Road region is detected employing a simple spatial differentiation technique to detect the plain textured area. Identification results of the diverse situation of Non-linear trail are included in this paper.

• 한국소음진동공학회논문집
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• 제19권11호
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• pp.1144-1150
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• 2009

Appropriate vibration model is required to predict in advance the vibration level of a large vehicle which carries sensitive electronic/mechanical equipments and drives often on the unpaved and/or off-road conditions. Central tire inflation system(CTIS) is recently adopted to improve the mobile operation of military and bulletproof vehicles. In this paper, full vehicle model(FVM) having 11 degrees of freedom and equipped with CTIS has been developed for a large vehicle which has $8\times8$ wheels$\times$driving wheels. Usability of the developed model is validated via road tests for three different modes (i.e. highway, country, and mud/sand/snow modes) and for various velocity conditions. The developed FVM can be used to predict the vibration level of the large vehicle as well as to determine the driving velocity criterion for different road conditions.

• 융합신호처리학회논문지
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• 제6권1호
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• pp.1-7
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• 2005

본 논문은 컴퓨터 비전 기반의 인식 기법으로 주간 시내도로에 정차된 버스와 보도 사이로 접근하는 측후방 차량을 탐지하는 시스템을 설명한다. 이 시스템은 승객의 안전한 하차를 위해 버스 운전자와 승객에게 차량의 접근 유무를 알려준다. 버스의 측후방 영상은 버스가 정차할 때마다 버스 중앙 출입문 상단에 장착된 카메라에서 입력된다. 이 영상에서 버스와 보도 사이에 탐색영역을 설정하고 이 영역에서 영상의 변화와 소벨 필터링으로 차량을 탐지한다. 탐지된 차량의 중심점을 잡은 후, 위치 및 가로 세로의 크기를 이용하여 거리, 속도, 방향을 알아낸다. 이 정보를 이용하여 하차하는 승객에게 위험한 상황이라 판단될 경우, 운전자와 승객에게 위험을 알려준다. 실험결과로 시내 주행시 87% 이상의 탐지율을 나타내었다.

• 로봇학회논문지
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• 제5권4호
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• pp.339-348
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• 2010

One of the requirements for autonomous vehicles on off-road is to move stably in unstructured environments. Such capacity of autonomous vehicles is one of the most important abilities in consideration of mobility. So, many researchers use contact and/or non-contact methods to determine a terrain whether the vehicle can move on or not. In this paper we introduce an algorithm to classify terrains using visual information(one of the non-contacting methods). As a pre-processing, a contrast enhancement technique is introduced to improve classification of terrain. Also, for conducting classification algorithm, training images are grouped according to materials of the surface, and then Bayesian classification are applied to new images to determine membership to each group. In addition to the classification, we can build Traversability map specified by friction coefficients on which autonomous vehicles can decide to go or not. Experiments are made with Load-Cell to determine real friction coefficients of various terrains.