• 한국생산제조학회지
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• 제20권5호
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• pp.639-645
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• 2011

Wheel-loader is a construction vehicle for uploading soil or sand into truck and transportation of materials, which requires large driving power and high rotational speed. To improve the working efficiency, the operator has to shift gears and control levers for bucket & boom simultaneously. Therefore, the automatic transmission has been introduced to enhance operator's convenience and enable effective operation. To develop the automatic transmission for the wheel-loader, technologies such as gears and a clutch-pack design and shift algorithm are required for improvement of shift quality. In this paper, the shift algorithm for the wheel-loader was developed and its shift pattern was analyzed. As the shift control is affected by the pressure profile for the clutch control, the shift quality depending on the pressure profile has been evaluated using experiment and simulation model analysis.

• 전기전자학회논문지
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• 제24권2호
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• pp.610-618
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• 2020

본 논문에서는 규칙기반 알고리즘을 이용한 수소연료전지/배터리 하이브리드 철도차량 모델링을 제시한다. 모터의 운전영역에 따른 토크 곡선을 계산하여 견인 시스템의 구동 전력을 결정하고 철도차량의 각 운전 모드에 적용하여 전기 시스템을 모델링 한다. 전기 시스템의 전력은 규칙기반 알고리즘을 이용한 에너지 관리시스템(Energy Management System, EMS)으로 결정한다. 배터리의 충전상태(State Of Charge, SOC)에 따라 운전 영역을 세분화하여 수소 소비량을 효율적으로 관리한다. 제안하는 철도차량 모델링의 타당성은 MATLAB/Simulink 시뮬레이션을 통해 검증한다.

• 제어로봇시스템학회논문지
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• 제22권7호
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• pp.552-556
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• 2016

Obstacle detection is a key feature in the safe driving control of electric wheelchairs. The suggested obstacle detection algorithm was designed to provide obstacle avoidance direction and detect the existence of cliffs. By means of this information, the wheelchair can determine where to steer and whether to stop or go. A 3D depth camera (Microsoft KINECT) is used to scan the 3D point data of the scene, extract information on obstacles, and produce a steering direction for obstacle avoidance. To be specific, ground detection is applied to extract the obstacle candidates from the scanned data and the candidates are projected onto a 2D map. The 2D map provides discretized information of the extracted obstacles to decide on the avoidance direction (left or right) of the wheelchair. As an additional function, cliff detection is developed. By defining the "cliffband," the ratio of the predefined band area and the detected area within the band area, the cliff detection algorithm can decide if a cliff is in front of the wheelchair. Vehicle tests were carried out by applying the algorithm to the electric wheelchair. Additionally, detailed functions of obstacle detection, such as providing avoidance direction and detecting the existence of cliffs, were demonstrated.

• 대한인간공학회지
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• 제22권2호
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• pp.15-28
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• 2003

The one of the most important factors is the platoon design on developing AH3(Advanced Highway System), as it is related to traffic efficiency and drivers' safety. This study was evaluated that how much speed is comfortable for drivers and how long distance is appropriate for vehicular gap of platoon by measuring drivers' physiology signal and sensibility. A fixed-based AHS simulator was developed by using a real vehicle cockpit and the restructured part of Korean highway for human factors evaluation. The EEG(electroencephalogram), ECG (electrocardiogram) and GSR(Galvanic Skin Response) were measured for obtaining drivers' physiology signal according to the change of speed and gap. The brain wave(${\alpha},\;{\beta},\;{\delta},\;{\theta}$) by EEG, the response of the autonomic nervous system. the sympathetic and parasympathetic nervous system, by ECG, and relax-arousal situation by GSR were analyzed. The SD(Semantic Differential) method was also applied to evaluate drivers' sensibility by 5-grade evaluation scale with 96 adjectives. SSQ(Simulator Sickness Questionnaire) was used to measure the simulator sickness of pre and post driving, two times. As the results, drivers were comfortable with 120km/h speed of platoon and lam to 15m vehicular distance. The results of this study may differ from the adaption of the reality because of many parameters. However, the purpose of this study is show to significant results of the drivers' safety and the acceptability of human factors evaluation.

• 설비공학논문집
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• 제26권3호
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• pp.122-129
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• 2014

In order to extract shaft power from thermal energy in a R134a Rankine cycle as waste heat recovery system of a passenger car, a scroll expander has been designed. Algebraic spiral is adopted as the base curve for scroll wrap profile in the compact scroll design. About 19% reduction in scroll diameter is accomplished when compared to the conventional involute scroll. Performance analysis on the designed scroll expander shows that the expander efficiency is 85.5% at the vehicle speed of 120 km/hr and it decreases to 67.2% at 60 km/hr, provided that the scroll clearance is kept at 10 ${\mu}m$. The expander can produce shaft power equivalent to about 13~14% of the driving power within the speed range of 60~120 km/hr.

• 에너지공학
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• 제18권2호
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• pp.136-140
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• 2009

자동차 공회전은 운전자의 운전 만족도에 여러 영향을 미친다. 또한 보다 높은 연료 경제성의 요구가 고조됨에 따라, 자동차 생산자들은 계속적으로 보다 나은 운전조건의 혜택에 관심을 갖는다. 스파크 점화기관의 공회전에서 기관의 안정성은 연소변동에 의해 좌우되며, 기관의 안정성은 연료분사시기, 점화시기, 그리고 공기연료비 등의 요소들에 영향을 받게 된다. 본 연구에서는 공회전에서 연료분사시기, 점화시기 그리고 공기연료비 등에 따라, 연소의 안정성과 변동율에 미치는 영향을 조사하였다.

• 한국인터넷방송통신학회논문지
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• 제11권5호
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• pp.47-52
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• 2011

본 논문에서는 주행 중 타이어와 노면이 마찰하면서 발생하는 초음파 신호에서 이물질로 인해 야기되는 우성주기를 검출하여 타이어 손상 유무를 판별하는 알고리즘에 대해 연구하였다. 손상된 타이어에서 획득한 초음파 신호의 포락선에 대해 전력스펙트럼을 산출하고 통계적 처리에 의한 임계값을 설정함으로써 우성주기를 판별하는 알고리즘을 제안하였다. 모의실험 결과, 시속 80km/h로 주행 시 초음파 신호의 포락선에 대해 전력스펙트럼의 피크주기 97.6ms에 비해 제안된 알고리즘의 우성주기는 100ms로서 포락선 피크의 평균주기 101.24ms를 기준으로 하였을 때 더 정확한 주기 측정 결과를 보였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.652-654
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• 2015

Integrated switched reluctance motor drive as an electric vehicle battery charger is presented in this paper. The SRM, which is used as the traction power in the driving mode, is used in the charge circuit to improve the power factor of charging system. The charging circuit can share the power switches of the asymmetric converter and phase windings of SRM to charge the battery, and can reduce the size and cost of the system in the plug-in system. To keep the rotor at standstill, zero torque control method is proposed. Since the inductances of the SRM windings are not same at any stop position, the charger controller controls the reference current to satisfy the total charging current with PFC and zero torque condition. A novel cubic equation method is proposed as a current reference distributor of the charging controller. Simulations are performed by MATLAB software and results satisfy the Effectiveness of proposed battery charging system.

• Advances in Automotive Engineering
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• 제1권1호
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• pp.143-152
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• 2018

In this study an economical image stitching algorithm for use in automotive industry is developed for retrofittable panoramic image assistance applications. The aim of this project is to develop a driving assistance system known as Panoramic Parking Assistance (PPA) which is cheap, retrofittable and compatible for every type of automobiles. PPA generates bird's eye view image using cameras installed on the automobiles. Image stitching requires to get bird's eye view position of the vehicle. Panoramic images are wide area images that cannot be available by taking one shot, attained by stitching the overlapping areas. To achieve correct stitching many algorithms are used. This study includes some type of these algorithms and presents a simple one that is economical and practical. Firstly, the mathematical model of a wide view of angle camera is provided. Then distorted image correction is performed. Stitching is implemented by using the SIFT and SURF algorithms. It has been seen that using such algorithms requires complex image processing knowledge and implementation of high quality digital processors, which would be impracticle and costly for automobile use. Thus a simpler algorithm has been developed to decrase the complexity. The proposed algorithm uses one matching point for every couple of images and has ease of use and does not need high power processors. To show the efficiency, images coming from four distinct cameras are stitched by using the algorithm developed for the study and usability for automotive application is analyzed.

• Journal of Advanced Marine Engineering and Technology
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• 제23권3호
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• pp.292-299
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• 1999

DC motors are widely used in many industrial fields as the actuator of the robot and the driving power motors of the electrical vehicle, Usually in the sensors of DC motors such as the encoder the tachogenerator and the potentiometer etc. are applied, But usage of these sensors results in the increased price and operating cost such that the application of the motors are limitted. To solve this problem another method to construct low cost control system is investigates. In this paper a new speed control method for DC motor is proposed. This method uses motor parameters instead of using speed or position sensors. In this way the angular velocity is estimated by the measure-ment values of the armature voltage and current instead of measuring the sensor signal. This paper presents an alorithm for estimating the angular velocity of DC motor The effectiveness of the proposed method is verified by experimental results. Also the applicability of the proposed method is presented by applying to the velocity contol of a wheeled mobile robot.