• 한국자동차공학회논문집
• /
• 제19권3호
• /
• pp.113-121
• /
• 2011

Rollover accident is one of the serious traffic accident and rollover accident takes high portion of all accident. The most common type of rollover is a tripped rollover which occupy 95% of all type of single-vehicle rollover. Tripped rollover occurs when a vehicle leaves normal road way and tripped by loose gravel, soil of fixed object such as guard rail, curbs and ditches. And the rest of the type of rollover is un-tripped rollover. An un-tripped rollovers that occurs during high-speed collision avoidance maneuvers. In this paper, presents the explanation of the un-tripped rollover test method and procedure, additionally this paper deals with various occurrence in the un-tripped test such as occurring excessive tire camber in the un-tripped test, tire side-wall contact with road surface and roll oscillation. And this paper analyzes the analysis of the roll rate amplitude in specific frequency through the FFT (Fast Fourier Transform) and the roll angle at the steering reverse timing which is the Fishhook test roll rate feedback time. Finally, this paper analyzes the relations between the estimated steady state roll gain and rollover stability.

• ETRI Journal
• /
• 제40권1호
• /
• pp.26-38
• /
• 2018

To overcome considerable path loss in millimeter-wave propagation, high-gain directional beamforming is considered to be a key enabling technology for outdoor 5G mobile networks. Associated with beamforming, this paper investigates propagation power loss characteristics in two aspects. The first is beamwidth effects. Owing to the multipath receiving nature of mobile environments, it is expected that a narrower beamwidth antenna will capture fewer multipath signals, while increasing directivity gain. If we normalize the directivity gain, this narrow-beamwidth reception incurs an additional power loss compared to omnidirectional-antenna power reception. With measurement data collected in an urban area at 28 GHz and 38 GHz, we illustrate the amount of these additional propagation losses as a function of the half-power beamwidth. Secondly, we investigate power losses due to steering beam misalignment, as well as the measurement data. The results show that a small angle misalignment can cause a large power loss. Considering that most standard documents provide omnidirectional antenna path loss characteristics, these results are expected to contribute to mmWave mobile system designs.

• 한국전자통신학회논문지
• /
• 제13권6호
• /
• pp.1199-1206
• /
• 2018

복합 위상천이기 구성은 배열안테나를 부 배열로 구성한 후, 부 배열 내부에는 일반적인 위상천이기를 사용하고, 부 배열 단위에는 실시간 지연 위상천이기를 사용하는 구성이다. 상기 구성은 빔 편이 현상을 효율적으로 개선할 수 있으나, 배열 구성이 적절하지 않으면 위상배열안테나 주 빔의 주파수 별 이득 편차가 발생하게 된다. 이와 같은 문제를 해소하기 위해 시스템 설계 주요 요구사항인 비 대역폭, 최대 빔 조향 각도 그리고 최대 이득 편차 제한 기준을 기반으로 효율적인 배열을 구성할 수 있는 간소화된 수식을 제시하였다.

• 한국통신학회논문지
• /
• 제27권3C호
• /
• pp.241-247
• /
• 2002

본 논문에서는 여러 개의 첩 광섬유 격자( Chirped fiber gratings CFGs )와 한 개의 파장 가변광원을 이용하 연속적으로 빔의 주사 방향을 조정할 수 있는 송신용 선형 위상배열 안테나용 실 시간지연 선로를 제안하였다. L-밴드, S-밴드 그리고 X-밴드에서 측정된 CFG의 평균 군 지연 기울기는 177 ps/nm이었다. 최대 빔 주사각을 180$^{\circ}$로 설계한 4개의 안테나 소자로 구성된 10 GHz 송신용 선형 위상배열 안테나 구조에서 전산 모의 실험 결과로 얻은 최대이득은 11.6 dB로 나타났다.

• 제어로봇시스템학회논문지
• /
• 제13권5호
• /
• pp.414-421
• /
• 2007

This paper presents a engine/brake integrated VDC(Vehicle Dynamic Control) system using neural network algorithm methods for wheel slip and yaw rate control. For stable performance of vehicle, not only is the lateral motion control(wheel slip control) important but the yaw motion control of the vehicle is crucial. The proposed NNPI(Neural Network Proportional-Integral) controller operates at throttle angle to improve the performance of wheel slip. Also, the suggested NNPID controller performs at brake system to improve steering performance. The proposed controller consists of multi-hidden layer neural network structure and PID control strategy for self-learning of gain scheduling. Computer Simulation have been performed to verify the proposed neural network based control scheme of 17 dof vehicle dynamic model which is implemented in MATLAB Simulink.