• 한국자동차공학회논문집
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• 제23권6호
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• pp.633-641
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• 2015

The ROM (roll over mitigation) system is a next-generation suspension system that can improve vehicle-driving stability and ride comfort. Currently, mass-produced safety systems, such as ESC (electronic stability control) and ECS (electronic control suspension), enable measurements of longitudinal and lateral acceleration as well as yaw rate through inertial sensor clusters, but they lack direct measurements of the roll angle. Therefore, in this paper, a roll angle estimation algorithm from ESC system sensors and tire normal force has been proposed. Furthermore, this study presents a method for roll over mitigation force distribution between the front and rear of a ROM system. Performance and reliability of the roll angle estimation and roll over mitigation force distribution were investigated through simulations. The simulation results showed that the proposed control algorithm and strategy are reliable during vehicle rollovers.

• 대한임베디드공학회논문지
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• 제17권5호
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• pp.257-263
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• 2022

Active stabilizers use signals such as steering angle, yaw rate, and lateral acceleration to vary the roll stiffness of the front and rear suspension depending on the vehicle's driving conditions, and are attracting attention as RSC (Roll Stability Control) system that suppresses roll when turning and improves ride comfort when going straight. Various studies have been conducted in relation to active stabilizer bars and RSC systems. However, accurate modeling of passive stabilizer model and active stabilizer model and vehicle dynamics analysis result verification are insufficient, and performance result analysis related to vehicle roll angle estimation and electric motor control is insufficient. Therefore, in this study, an accurate vehicle dynamics model was constructed by measuring the passive/active stabilizer bar model and component parameters. Based on this, the analysis result with high reliability was derived by comparing the roll angle estimation algorithm based on the lateral acceleration and suspension of the vehicle with the actual vehicle driving test result. In addition, it was intended to accurately analyze the motor torque characteristics and roll reduction effects of the electric motor-driven RSC system.

• Journal of Positioning, Navigation, and Timing
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• 제6권4호
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• pp.135-140
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• 2017

This paper proposes a signal merging algorithm to increase the signal-to-noise ratio (SNR) of a GPS correlator output to estimate the roll angle of a rotating vehicle in a weak GPS signal environment. Rotation Locked Loop (RLL) algorithm is used to estimate a roll angle using the characteristics that the power of the GPS signal measured at the receiver of a rotating vehicle varies periodically. First, delay times are calculated to synchronize GPS signals using satellites' and receiver's positions and the rotation frequency of a vehicle, and then correlator outputs are delayed in time and merged with each other, resulting in the increase of an SNR in a correlator output. Finally, simulations are conducted and the performance of the proposed algorithm is validated.

• 한국항공우주학회지
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• 제43권2호
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• pp.133-140
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• 2015

본 논문에서는 단일 저가형 범용 GPS 수신기와 롤 축 각속도계를 이용하여 롤 회전 비행체의 롤 자세각을 결정하는 기법을 제안한다. 비행체에 부착된 GPS 수신기의 신호 수신강도는 GPS안테나가 향하는 방향과 비행체의 종축이 이루는 평면 내에 GPS위성이 존재할 때 최대가 된다. 비행체의 종축이 속도벡터와 일치한다고 가정하면, 비행체에 대한 GPS위성의 상대위치벡터를 이용하여 GPS 안테나 신호가 최대일 때의 롤 각을 결정할 수 있다. 롤 각 결정의 정밀도를 높이기 위해 롤 축 각속도계를 이용한 칼만필터를 구성하였다. 6-자유도 시뮬레이션을 통해 제안된 방법의 성능을 검증하였다.

• 한국항공우주학회지
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• 제48권9호
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• pp.681-689
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• 2020

본 논문에서는 유도형 탄약의 모사 기체를 제작하고 공중에서 탄체에 롤축 회전을 인가한 뒤 롤축 저속 회전 중인 탄체의 롤각 추정 성능을 실험적으로 검증한 방법과 결과를 소개한다. 멀티로터형 무인기를 모선으로 사용해 유도형 탄약 모사 기체에 초기 속도와 고도를 부여하였으며 탄체 투하, 탄체 회전, 롤각 추정 및 안정화로 이어지는 비행 시험 시나리오를 통해 롤각 추정 결과를 분석한다. 약 200m의 고도에서 수평 방향으로 15m/s의 속력으로 탄체를 투하한 뒤 내부의 반동차(Reaction Wheel)를 사용하여 탄체를 회전시켰으며 특히, 상용 GPS/INS와의 비교를 통해 롤각 추정 결과를 제시한다. 아울러, 반동차를 이용하여 공중에서 탄체를 롤축 회전시키는 메커니즘들을 비교하고 실제 구현한 결과도 소개한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.153-155
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• 2004

This paper proposes a real-time approach on the rotational motion estimation and correction for the roll stabilization of the sight system. This method first estimates a rotation center by the least-mean square algorithm based on the motion vectors of some feature points. And, then, a rotation angle is searched for a best matching block between a reference block image and seccessive input images using MPC(maximum pixel count) matching criterion. Finally, motion correction is performed by the bilinear interpolation technique. Various computer simulations show that the estimation performance is good and the proposed algorithm is a real-time implementable one to the TMS320C6415(500MHz) DSP.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.40-40
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• 2000

Generally a RF AGC controls the roll gap using the variation of rolling force caused by the roll eccentricity and the entry thickness of material, but these can not be classified. The Feed- forward AGC method, which controls the next stand roll 9ap by estimation the skid mark of the previous stand output thickness is needed to supplement the shortage of RF AGC. In this paper, an improved filtering method of skid mark which take account of the kinds of materials, the final objective thickness and the roll speed is proposed, In addition, an improved estimation method of control point using the speedometer and looper angle is suggested, Via simulation, the performance improvement of the suggested FF AGC method is verified.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 춘계학술대회논문집
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• pp.168-171
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• 2003

Generally RF AGC (Roll Force Automatic Gauge Control) controls the roll gap using the variation of rolling force caused by the roll eccentricity and the entry thickness of material, but RE AGC takes the bad effect of the roll eccentricity. The Feed-forward (FF) AGC method, which controls the next stand roll gap by the estimation of the thickness variation due to skid mark is needed to supplement the shortage of RF AGC. In this paper, an adaptive filtering method which takes account of the kind of material, the final objective thickness and the rolling speed is proposed to predict skid mark thickness variation. In addition, an improved estimation method of control point using a speedometer and looper angle is suggested. Via on line test, the performance improvement of the suggested FF AGC method is verified.

• 제어로봇시스템학회논문지
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• 제10권7호
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• pp.611-617
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• 2004

This paper presents a simple method of rotational motion estimation and correction for roll axis stabilization of an image. The scheme first computes the rotation center by taking least squares of selected local velocity vectors, and the rotational angle is found from special subset of motion vectors. Roll motion correction is then performed by the nearest neighbor interpolation technique. To show the effectiveness of our approach, the synthetic and real images are evaluated, resulting in better performance than the previous ones.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2005년도 창립60주년 기념 추계 학술대회
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• pp.194.1-194.1
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• 2005