• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.8 s.179
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• pp.1899-1909
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• 2000

This paper proposes a new $H_{\infty}$ yaw moment control scheme using brake torque switching for improving vehicle performance and stability especially in high speed driving. In the scheme, one wheel is selected, depending on the vehicle states, at which a brake torque for control is applied. Steering angles are modeled as a disturbance to the system and the $H_{\infty}$ controller is designed to minimize the difference between the performance of the vehicle and that of the desired model. Its performance robustness as well as stability robustness to system parameter variations is assured through ${\mu}$-analysis. Various simulations with a nonlinear 8-DOF vehicle model show that proposed controller enhances the vehicle performance and stability under disturbances and parameter variations as well as under the normal driving condition.

• Journal of Auto-vehicle Safety Association
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• v.7 no.2
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• pp.32-38
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• 2015

A sine with dwell test is well known as a test scenario for evaluation of performance of electronic stability control(ESC) on passenger vehicles and heavy commercial vehicles. However, when it comes to ESC for medium commercial vehicles, the test scenario has not been established yet. In this paper, the sine with dwell test was modified considering characteristics of medium commercial vehicles. The three main modifications of the original test scenario are the steering angle level, steering frequency, and loading condition of the vehicle. These modifications are derived from simulation study for different medium commercial vehicles. From simulation study, it was shown that the ESC system for medium commercial vehicle is objectively evaluated by the proposed test scenario. A clear improvement on vehicle stability was seen in the results when ESC system was used.

• Journal of Korean Society of Transportation
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• v.27 no.3
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• pp.71-77
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• 2009

The ubiquitous transportation system environments make it possible to collect each vehicle's position and velocity data and to perform more sophisticated traffic flow management at individual vehicle or platoon level through V2V and V2I communications. The VISSIM simulation experiments were performed to address the issues in developing the preventive congestion management algorithm proposed in the companion paper. Traffic flow stability measures were developed based on the platoon profile, which enables us to explicitly consider traffic flow stability in traffic flow management. Traffic flow management strategies according to the traffic flow states were proposed: Maintain the equilibrium speed for free flow state, maintain the traffic flow stability by platoon control for critical state, and surpress the shock wave propagation for congested state. And finally potential benefit of the proposed traffic flow management scheme was evaluated based on the simulation experiment results. It is considered that extensive field experiments should be performed to confirm the simulated results.

• 한국IT서비스학회:학술대회논문집
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• 2009.05a
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• pp.509-512
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• 2009

최근 차량용 IT 기술이 발달함에 따라 네비게이션, 위치추적, 인터넷 접수, 원격 차량 진단, 사고감지, 긴급구난, 교통정보 등을 제공하는 서비스들이 등장하고 있다. 또한 차량의 편의성과 안정성을 추구함과 동시에 친환경 등에 대한 요구도 증가하고 있다. 그리고 최근 차량 상호간 정보의 교환이 더욱 필요해짐에 따라 차량간의 무선 통신 기능이 중요해지고 있으며 차량 내의 네트워크 기술에 대한 연구도 필요하다. 현재 차량 내 네트워크로는 CAN, LIN, MOST등의 유선으로 된 버스 시스템을 중심으로 한 차량 제어 시스템과 멀티미디어 시스템으로 크게 구분할 수 있다. 그러나 자동차 내에 장치 배선이 복잡해짐에 따라 차량의 무게 증가, 고장율의 증가, 연비 저하 등으로 이어지고 있다. 이러한 문제를 보완하기 위해 차량 내에 무선 센서 네트워크 시스템과의 통합 개발이 요구되고 있다. 본 논문에서는 빠르게 발전하고 있는 차량 내 네트워크에 대한 기술개발 동향을 분석하고, 유무선 통합형 차량 내 네트워크 응용 서비스들을 제시하고자 한다.

• Information and Communications Magazine
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• v.34 no.5
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• pp.10-18
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• 2017

본고에서는 자율주행 완성차와 자율주행 융합 부품 관련 기술과 국내외의 자율주행자동차 산업정책과 기술 개발 동향을 살펴본다. 자율주행 차량은 고안전, 고편의, 친환경, 신생태계의 자동차 산업에서의 4가지 미래 키워드를 만족시키는 기술로서 국가차원의 전략적 양성이 필요하다. 자율주행자동차 산업은 자동차 산업 생산기반 및 우리나라의 IT, 반도체 등의 기술 활용이 가능하며, 아직 상용화 되지 않은 분야로서 자율주행 분야의 상용화 기술 조기 확보 시 세계시장을 선점 할 수 있다. 따라서 자율주행 완성차 및 부품업체 등의 복수 수요기관이 참여하여 중소, 중견 부품업체 수요처 다각화 및 생태계 체질 개선, 자율주행 핵심부품 및 제어를 위한 SW 등 원천기술 확보 및 수입대체, 자율주행 기술과 관련 센서 선도기술 개발 및 글로벌 중견기업 육성을 기대 할 수 있다. 또한 빠르게 자율주행자동차 관련 기술개발이 진행되고 전장 부품이 자동차에서 차지하는 비중이 커짐에 따라 서로 연결되어 동작하는 전기전자 시스템의 기능안전 확보의 필요성이 대두되고 있다. 이미 해외에서는 자동차 전자제어 시스템 의무 장착을 강화시키는 추세이며 차량 안전 확보를 위해 전자제어장치의 기능 안정성의 중요성과 기술 표준의 필요성을 기반으로 자동차 기능 안전선 국제 표준을 규격화하고 있다. 따라서 본고에서는 국내외의 자율주행차량 분야의 산업 현황과 기술 동향을 살펴봄으로써 시장의 현황을 파악하고 자동차 기능 안전성 국제 표준에 관하여 알아본다.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.9
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• pp.38-45
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• 2016

For higher efficiency and reliability of railroad trains with many electronic sensors and actuators, a distributed control system with which electronic components communicate with each other in a distributed manner via a data network is considered. This paper considers Ethernet-based Train Communication Network (TCN) for this purpose and proposes a methodology to optimize the topology in terms of transmission latency and reliability, each of which is modeled as the number of traversing backbone nodes and the number of cables between vehicles, respectively. An objective function is derived accordingly and a closed-form optimum is obtained by relaxing the integer constraint of the number of vehicles for a unit network. Then, the final integer optimum is searched around it. Through numerical evaluation, the validity of the proposed methodology and the characteristics of the resulting solutions are shown.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.125-132
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• 2017

Vehicular safety service reduces traffic accidents and traffic congestion by informing drivers in advance of threats that may occur while driving using vehicle-to-vehicle (V2V) communications in a wireless environment. For vehicle safety services, every vehicle must broadcasts a Basic Safety Message(BSM) periodically. In congested traffic areas, however, network congestion can easily happen, reduce the message delivery ratio, increase end-to-end delay and destabilize vehicular safety service system. In this paper, to solve the network congestion problem in vehicle safety communications, we approximate the relationship between channel busy ratio and the number of vehicles and use it to estimate the total network congestion. We propose a new context-aware transmit power control algorithm which controls the transmission power based on total network congestion. The performance of the proposed algorithm is evaluated using Qualnet, a network simulator. As a result, the estimation of total network congestion is accurately approximated except in specific scenarios, and the packet error rate in vehicle safety communication is reduced through transmit power control.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.458-459
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• 2008

이 논문은 자기부상열차 속력에 따른 부상제어기 성능을 분석한다. 현재 실용화 사업은 시속 110km/h 속력으로 부상공극 8 mm 기준으로 상하 3 mm 이하 변화를 목표로 개발 중에 있다. 부상제어기의 안정성에 영향을 미치는 외란으로는 가이드웨어 처짐, 크로스아암에 의한 레일 처짐, 레일 불균일, 레일 연결부 단차 등이 있다. 이러한 외란이 복합적으로 작용하지만, 설계 단계에서 각각의 영향을 단순화하여 독립적으로 그 영향을 분석할 필요가 있다. 본 논문에서는 차량속력에 따른 가이드웨어 처짐이 부상제어기에 미치는 영향을 분석한다. 하나의 전자석과 유연레일을 모델링하고 상태궤환을 갖는 제어기를 제안하여 속력에 따른 부상공극 변화를 관찰한다. 모의시험 결과 12 mm 레일의 휘어짐 상황에서 속력에 따라 부상 공극 변화가 커지지만, 실용화 사업의 목표를 달성함을 알 수 있었다.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1126-1131
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• 2007

This paper presents unified chassis control (UCC) to improve the vehicle lateral stability. The unified chassis control implies combined control of active front steering (AFS), electronic stability control (ESC) and continuous damping control (CDC). A direct yaw moment controller based on a 2-D bicycle model is designed by using sliding mode control law. A direct roll moment controller based on a 2-D roll model is designed. The computed direct yaw moment and the direct roll moment are generated by AFS, ESP and CDC control modules respectively. A control authority of the AFS and the ESC is determined by tire slip angle. Computer simulation is conducted to evaluate the proposed integrated chassis controller by using the Matlab, simulink and the validated vehicle simulator. From the simulation results, it is shown that the proposed unified chassis control can provide with improved performance over the modular chassis control.

• Journal of the Institute of Convergence Signal Processing
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• v.22 no.4
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• pp.171-178
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• 2021

Caravans are easily affected by external physical factors and often cause dangerous situations for passengers. Therefore, in order to secure the stability of the passenger, there is a need to develop a sway reduction device capable of preventing the sway phenomenon in advance. This paper aims to minimize the hitch angle between the tow vehicle and the caravan. Specifically, the initial instability of the caravan is detected through an IMU sensor mounted on each of the tow vehicle and the caravan, and a control value is calculated to reduce errors from the Hitch angle and Hitch yaw rate using a PID controller. Different braking torques are generated, distributed, and controlled on the left and right brakes of the caravan according to the calculated control value. It could be verified through the driving experiment that the hitch angle was decreased compared to the case where the performance of the sway reduction device was not controlled, and the transverse stability improvement rate was improved by 94.49% compared to before control.