• 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.

• 한국철도학회논문집
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• 제10권4호
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• pp.414-419
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• 2007

The contact characteristics of the current collection system are investigated by analyzing data collected during a test run of the Korean high speed rail vehicle. For the analysis, the signals from accelerometers and load cells attached to the various parts of the pantograph are analyzed in both the time and frequency domains. In the frequency domain, the pantograph response consists of low frequency components related to the rigid-body motion of the panhead assembly and high frequency components due to the structural vibration modes of the pantograph. The analysis shows that the inclusion of the high frequency structural vibration modes of the pantograph in the contact force calculation has a negligible effect on the predicted mean value of the contact force but significantly affects the magnitude of its fluctuations. This finding implies that numerical simulations using lumped element models of the pantograph may accurately predict the mean contact force but is limited in its capacity for predicting the fluctuation about the mean. Since the ratio of the fluctuation to the mean in the contact force increases with increased train speed, the limitation of the predictions based on numerical simulation results becomes more pronounced at higher train speed.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.905-911
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• 2009

The viscosity drive method by the wheel which is widely used in the conventional railway systems needs a large friction force between the wheel and the guide-rail, which brings on a thrust force for a quick acceleration and a high-speed travelling. In addition, the viscosity drive method needs an increase of the vehicle weight for a large friction force. However, a maglev train is possible to be driven by the electro-magnet instead of the wheel, which produces a levitation and thrust force without any contact. In general, low-speed maglev train uses a linear induction motor(LIM) for propulsion that is operated under 300[km/h] due to the power-collecting and end-effect problems of LIM. In case of high-speed maglev train, a linear synchronous motor(LSM) is more suitable than LIM because of a high-efficiency and high-output properties. LSM has a driving principle as same as a conventional rotary synchronous motor(RSM), and the torque of RSM becomes the thrust force of LSM. A conventional LSM has relatively large air-gap compared with a conventional RSM. So, it must be achieved a design that is considered normal force by finite-asymmetric structure, end-effect on the entry and exit part, and support structure of a moving part. Therefore, in this research, authors accomplish a conceptualizing and basic design of a small-scaled LSM, and characteristics analysis using FEM.

• 한국ITS학회 논문지
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• 제22권3호
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• pp.116-130
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• 2023

고속도로는 중장거리 지역 간을 연결하는 자동차 전용도로로 철도 및 항공 수단보다 접근성과 이동성이 우수하여 화물 수송의 중추적인 역할을 담당하고 있다. 그러나 기존의 고속도로를 이용하는 화물수송실적은 차종 구분의 혼재, 개별 화물차량의 화물적재량 파악의 어려움으로 정확한 산정에 한계가 있다. 따라서 본 연구에서는 고속도로 온라인 데이터의 분석을 통하여 보다 신뢰성있는 화물수송실적 산정 방법론의 틀을 제시하고자 하였다. 자동요금징수시스템로부터 수집된 데이터를 활용하여 고속도로 구간별 통행실적(대·km/일)을 도출하였으며 차량제원정보데이터와 고속 및 저속축중기 데이터로부터 차종별 화물 적재 원단위(톤/대)를 도출하였다. 본 연구는 기존에 제시되고 있지 않은 고속도로 구간별, 차종별 화물수송실적을 산정하는데 주요 목적이 있으며, 개방식 영업소, 민자고속도로 등을 모두 연계한 수송실적산정방법을 제시하였다는데 기존 연구와의 차별성을 가진다.

• 한국분무공학회지
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• 제18권3호
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• pp.155-160
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• 2013

Worldwide harmonized light-duty vehicle test procedure (WLTP) for emission certification has been developed in WP.29 forum in UN ECE since 2007. The test procedure is expected to be applied to Korean light-duty diesel vehicles at the same time of adoption in Europe. The air pollutant emissions from light-duty vehicles have been regulated with weight per distance travelled which means the driving cycles can affect the results. The six Euro-5 light-duty diesel vehicles including sedan, SUV and truck have been tested with WLTP, NEDC which is used for emission certification for light-duty diesel vehicles, and CVS-75 to estimate how much particle number emission can be affected by different driving cycles. The averaged particle number emissions have not shown statistically meaningful difference. The maximum particle number emission have been found in Low speed phase of WLTP which is mainly caused by cooled engine conditions. The amount of particle number emission in cooled engine condition is much different as test vehicles. It means different technical solution is required in this aspect to cope with WLTP driving cycle.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제53권12호
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• pp.718-724
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• 2004

This study investigates the design factors of Interior Permanent Magnet Synchronous Motor(IPMSM) which is applied to Hybrid electric vehicle as a driving power. Recently, there are many studies of IPMSM for application to Hybrid Electric Vehicle, because IPMSM has characteristics of high torque, high power density and high efficiency which come from reluctance torque due to difference of inductance as well as magnet torque. This study analyzes the inductance and design characteristics of IPMSM by using finite element method and focuses on design and analysis of IPMSM which can operates with high efficiency at low speed range. For this embodiment, magnet shape is changed from conventional block type to arc type without any change of outline dimension of motor and this change of magnet shape makes it possible to increase back EMF and sinusoidal waveform. Analysis results are verified by test of improved and embodied motor. As a test result , increased back EMF and sharply decrease of harmonics are secured and through this contribution of reduced fuel consumption of Hybrid electric vehicle is expected.

• 한국자동차공학회논문집
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• 제20권5호
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• pp.88-94
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• 2012

Development trend of modern HSDI diesel engine is now focusing on low fuel consumption and emission because of strong interest in global environmental protection. Two big branches of criteria for modern diesel engine development are down sizing and down speeding. Down sizing keeps engine operation condition to the direction of higher load and thus pursuing for better thermal efficiency. But this may cause degraded vehicle dynamic performance because of reduced back up torque. Down speeding keeps engine operation condition to the direction of slightly higher load and lower engine speed. Therefore reduction of back up torque can be limited within flat torque area. This study analyzed fuel economy effect of down speeding on a vehicle powered by HSDI diesel engine in aspect of engine friction work, intake and exhaust pumping work, exhaust hat loss and thermal loss of fuel leakage of fuel injection system. Contribution factor of each engine and vehicle related parameters under basic and down speeding condition were compared and work balance of down speeding during NEDC was analyzed.

• 한국통신학회논문지
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• 제42권1호
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• pp.241-249
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• 2017

최근 차량용 블랙박스의 보급이 확산됨에 따라 이를 법적 증거로 사용하는 경우가 증가하고 있으며, 이에 따라 영상데이터의 무결성 검증에 대한 필요성이 대두되고 있다. 그러나 임베디드 시스템으로 분류되는 블랙박스는 적은 용량과 낮은 처리속도를 가지므로 영상파일 저장과 무결성 검증 처리의 한계점을 가진다. 본 논문에서는 제한된 자원을 가진 블랙박스 환경에서 고속경량 해시함수 LSH와 HMAC의 안전성을 이용하여 영상파일의 무결성을 보장하는 기법을 제안한다. 또한 이 기법을 구현하여 블랙박스 기기에서 무결성 검증 시의 CPU Idle Rate를 측정한 실험 결과를 제시하고, 제안한 기법의 효과성과 실용 가능성에 대해 검증한다.

• Journal of Information Processing Systems
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• 제18권2호
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• pp.258-267
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• 2022

Weak over-the-horizon perception and blind spot are the main problems in intelligent connected vehicles (ICVs). In this paper, a V2V image transmission-based road condition warning method is proposed to solve them. The encoded road emergency images which are collected by the ICV are transmitted to the on-board unit (OBU) through Ethernet. The OBU broadcasts the fragmented image information including location and clock of the vehicle to other OBUs. To satisfy the channel quality of the V2X communication in different times, the optimal fragment length is selected by the OBU to process the image information. Then, according to the position and clock information of the remote vehicles, OBU of the receiver selects valid messages to decode the image information which will help the receiver to extend the perceptual field. The experimental results show that our method has an average packet loss rate of 0.5%. The transmission delay is about 51.59 ms in low-speed driving scenarios, which can provide drivers with timely and reliable warnings of the road conditions.

• 전력전자학회논문지
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• 제21권5호
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• pp.381-387
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• 2016

Many efforts have focused on the improvement of power density and efficiency by downsizing the motor and inverter. Recently, Toyota, Honda, and GM realized that the compact-sized motor uses the hairpin structure with increased space factor. Reducing the maximum torque from high-speed technique also makes it possible to design the high-power density model. Toyota and Honda used the newly developed power semiconductor IGBT to decrease conduction loss for high-efficiency inverter. In particular, Toyota used the boost converter to increase the DC link voltage for high efficiency in low-torque high-speed region. Toyota and GM also used the double-sided cooling structure for miniaturization of inverter for high-power density.