• 한국자동차공학회논문집
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• 제14권5호
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• pp.145-154
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• 2006

Each part of drum brake system is loaded by continual mechanical force and thermal force every time of braking, so enough strength and stability are required. Thermal characteristic is one of the important factors in drum brake systems design. This paper presents the thermal performance such as temperature distribution and thermal contact stress of drum brake system considering several braking patterns; 80th heat braking test mode, heat fade braking test mode, general road mode, steep slope road mode and off road mode. Transient heat transfer analysis and Thermo elastic contact analysis is executed to obtain the temperature distribution, and to evaluate thermal stress of drum brake by using ABAQUS/Standard code. This procedure of analysis can effectively be used to improve the quality problem of brake system and to get design guideline of the new product.

• Journal of Biosystems Engineering
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• 제27권6호
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• pp.501-512
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• 2002

Traction performance of off-road vehicles is estimated using slip-traction relationships Two zero condition accepted by ASAE have been used widely to obtain the slip-traction relationships of off-road vehicles. This study was carried out using the soil bin systems to investigate the characteristic of slip-traction curves obtained using two zero conditions defined by ASAE. which are driving and driven zero condition, and to present disadvantage of slip-traction relationship based on two zero conditions of ASAE. The results of this study are summarized as follows : 1. For the driving zero condition, the curve of slip-traction relationship shows some issues. The first question is that the slip is zero when the traction is zero. The second question is that the value of slip is smaller than that of corresponding real slip, as the rolling radius decreased f3r the setting zero condition with driving wheel. 2. For the driven zero condition. slip occurs when the traction is zero, which is more realistic results than driving zero condition. But when a zero condition is set, skid occurs and this result increased the rolling radius of tire and increased slip value f3r the specific traction value of whole slip range. This kind of trend was getting bigger as the soil is softer, or the tire inflation pressure is higher. 3. From the results of this study, it was found that slip-traction relationship obtained by two zero conditions of ASAE is not realistic in estimating the traction performance of off-road vehicles. And also slip-traction relationship obtained for the same experimental condition showed different result in accordance with chosen zero condition,

• 대한기계학회논문집B
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• 제35권6호
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• pp.577-583
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• 2011

비도로 차량용 디젤엔진의 Tier 4 interim 규제를 만족하기 위하여 입자상물질과 질소산화물 배출량은 현행 규제 대비 각각 95%, 30% 저감되어야 하며, 입자상 물질을 저감하기위한 방법으로 디젤산화촉매, 부분유량 매연 여과장치 및 매연여과장치가 비도로 차량용 디젤엔진에 적용될 수 있다. 또한 질소산화물을 저감하기위해 배기가스 재순환방법, 선택적 환원촉매와 희박 질소산화물 포집장치 등이 적용될 수 있다. 본 연구에서는 56kW급 off-road 차량에서의 입자상물질과 질소산화물을 저감하기위해 매연여과장치와 고압루프 배기가스재순환 시스템이 연구되었다. 실험결과로서 디젤산화촉매와 매연여과장치는 입자상물질을 저감하는데 매우 효과적이었으며 낮은 배압과 함께 출력손실도 5%이내였다. 고압루프 배기가스재순환을 적용한 결과 중 저부하 조건에서 효과적으로 질소산화물을 저감하였으며 배기가스재순환율이 높을수록 질소산화물의 저감율도 증가하였다.

• International Journal of Control, Automation, and Systems
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• 제3권4호
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• pp.509-523
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• 2005

We are developing a novel framework, PRIDE (PRediction In Dynamic Environments), to perform moving object prediction (MOP) for autonomous ground vehicles. The underlying concept is based upon a multi-resolutional, hierarchical approach which incorporates multiple prediction algorithms into a single, unifying framework. The lower levels of the framework utilize estimation-theoretic short-term predictions while the upper levels utilize a probabilistic prediction approach based on situation recognition with an underlying cost model. The estimation-theoretic short-term prediction is via an extended Kalman filter-based algorithm using sensor data to predict the future location of moving objects with an associated confidence measure. The proposed estimation-theoretic approach does not incorporate a priori knowledge such as road networks and traffic signage and assumes uninfluenced constant trajectory and is thus suited for short-term prediction in both on-road and off-road driving. In this article, we analyze the complementary role played by vehicle kinematic models in such short-term prediction of moving objects. In particular, the importance of vehicle process models and their effect on predicting the positions and orientations of moving objects for autonomous ground vehicle navigation are examined. We present results using field data obtained from different autonomous ground vehicles operating in outdoor environments.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1996년도 춘계학술대회논문집; 부산수산대학교, 10 May 1996
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• pp.203-208
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• 1996

This paper consider the control for the vehicle suspension system using electro-rheological damper. The study is performed by using of FLC(Fuzzy Logic Controller). The model used in the simulation is quarter car and the road disturbance is regarded as white noise random process with zero mean. Proposed control technique shows good agreement compared with the result from the conventional on-off/bang-bang type control technique.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 26-27 Oct. 1990
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• pp.643-647
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• 1990

Gunner primary sight(GPS) stabilization system lays line of sight(LOS) to find out a target and transmits informations to the fire control system (FCS). In a moving vehicle, accuracy of LOS and FCS depends on the design of GPS and servomechanism system. The heavy vibration of vehicle on the severe off-road environment degenerates the stabilization capability of GPS. In this study, to stabilize of elevation for GPS using the variable structure control, we derived the dynamic equation of GPS system and designed the variable structure controller. Computer simulation results fulfilled the static and dynamic stability of GPS using the variable structure control.

• 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.

• 동력기계공학회지
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• 제17권6호
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• pp.130-135
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• 2013

It is a research about the change in reduction efficiency and performance resulting from installation of the EGR cooler, which is the core technology reducing NOx in response to standards been tightened of exhaust controls for off-road vehicle. It can reduce NOx by altering combustion temperature and oxygen concentration by recycling high-temperature exhaust gas. The target engine was large diesel engine for construction machine through by which we were able to verify a rate of change in output and capabilities for a heat-exchange within cooler itself depending on the existence of EGR cooler system. We have acquired a emission reduction technology for a construction machine by testing the reduction performance and rate of change in output.

• 제어로봇시스템학회논문지
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• 제18권6호
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• pp.526-531
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• 2012

This paper, we describe the vector control of surface mounted PMSM (Permanent Magnet Synchronous Motor) using the fuzzy controller which is suggested algorithm. In these days, when vehicle is operated or not, whether the road is covered or not, the sensitivity of the steering column is not stable. To make up for it, the PI gain of a steering column controller is adjusted by experience. It becomes the price because it need a lot of sensor. Also it is difficult to implement robust control because we need a lot of parameters for variable road conditions which are the off road, the on road, a low battery voltage, a high battery voltage, a vehicle speed. In this paper, we propose fuzzy controller using the suggested algorithm which suitable for steering system. We test the fuzzy controller with the various condition. We get the good performance of fuzzy controller even if it is nonlinear system. We check a robust the fuzzy controller using the suggested algorithm.

• 한국자동차공학회논문집
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• 제11권4호
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• pp.135-143
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• 2003

In this study, a real-time simulation model was developed for tracked vehicles with in-arm type semi-active hydro-pneumatic suspension unit using MATLAB S-functions. Since the vehicle model uses relative coordinates and massless link elements, the developed model has an enhanced analytic time performance. Through the comparison of simulation results with multi-body software(DADS), the vehicle model is verified. A controller using on-off skyhook control algorithm is designed with the pilot-centre]led proportional valve based on conventional damper characteristics. Exploiting the developed tracked vehicle model with other subsystem model such as a controller model, a suspension unit model, and a test road model, computer simulations are carried out. Control simulation results with the developed tracked vehicle model show that the semi-active suspension control system has a better performance than the conventional suspension system.