• Journal of Auto-vehicle Safety Association
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• v.12 no.3
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• pp.13-19
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• 2020

This paper presents steering controller for unintended lane departure avoidance under crosswind using vehicle lateral disturbance estimation. Vehicles exposed to crosswind are more likely to deviate from lane, which can lead to accidents. To prevent this, a lateral disturbance estimator and steering controller for compensating disturbance have been proposed. The disturbance affecting lateral motion of the vehicle is estimated using Kalman filter, which is on the basis of the 2-DOF bicycle model and Electric Power Steering (EPS) module. A sliding mode controller is designed to avoid unintended the lane departure using the estimated disturbance. The controller is based on the 2-DOF bicycle model and the vision-based error dynamic model. A torque controller is used to provide appropriate assist torque to driver. The performance of proposed estimator and controller is evaluated via computer simulation using Matlab/Simulink.

• Transactions of Materials Processing
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• v.32 no.6
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• pp.376-383
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• 2023

The torsion bar, which is a steering torque sensor, is mounted between the steering pinion and the input shaft in the IPA(input pinion assembly). Accurate torque measurement is important to improve the sense of operation, and the straightness of the torsion bar can affect torque measurement. In this study, the amount of bending was measured and the exact shape was analyzed regarding the bending phenomenon in the press-fitting process for torsion bars. The effect of alignment error was analyzed through finite element forming analysis. Process data analysis was conducted for the double-end press fit model. If there is an alignment error of about 10% of the serration tooth height, the indentation load is reduced by about 10%. If there is an alignment error, the torsion bar is rotated.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.1077-1078
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• 2012

• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.9-11
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• 2009

자동차 EPS(Electric Power Steering)용 소용량 표면부착형 영구자석 동기전동기(SPMSM : Surface mounted Permanent Magnet Synchronous Motor)의 설계에는 주로 토크리플 및 코깅토크 저감이 설계목표로 결정되는데, 토크리플과 코깅토크는 치폭, 요크폭, 자석 극호각 등 전동기 형상에 영향을 많이 받는다. 특히, 자석 극호각에 따라 변동이 극심한데, 이는 출력특성이 공극 자속밀도 변화량에 크게 의존하기 때문이다. 한편, 일반적으로 토크리플과 코깅토크의 최소점은 각각 다르기 때문에, 소용량 SPMSM 설계시 큰 어려움으로 작용한다. 따라서 본 논문은 이러한 현상을 효과적으로 고려한 소용량 SPMSM 최적설계를 목적으로 하며, 600W급 고전압 EPS용 전동기 설계를 통해 연구의 타당성을 검증한다.

• ICROS
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• v.21 no.1
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• pp.31-36
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• 2015

운전자에게 편의성을 제공하는 차량의 주행관련 Advanced driver assist system (ADAS)에는 차량의 종방향과 횡방향 운동에 대한 제어기가 요구된다. 횡방향 제어를 위해서는 조향 시스템의 조향각 제어가 요구되는데 최근 구조적으로 간단하고 연비향상, 차량의 중량 감소, 빠른 응답성을 가지고 있는 전기적 파워 조향 (Electric power steering, EPS) 시스템이 자동차 산업에서 널리 사용되고 있다. 차량의 주행관련 ADAS를 사용하여 자율 주행 시 EPS 시스템은 상위 제어기에서 계산된 필요한 조향각을 추종 할 수 있도록 조향 핸들의 각 제어를 해야 한다. 그러나 일반적인 EPS 시스템은 운전자가 조향 핸들에 인가된 토크를 보조해 줄 수 있는 토크를 출력해 준다. 본 논문에서는 이러한 문제를 해결하는 방법들을 설명한다. 먼저 EPS 시스템의 기본 기능에 대해서 설명을 하고, 자율 추행 차량을 위한 조항 핸들의 각 제어를 위한 proportional-integral 제어, 슬라이딩 모드 제어 (Sliding mode control), 관측기 기반 비선형 댐핑 제어(Observer based nonlinear damping control) 등과 같은 다양한 기법의 제어 알고리즘들에 대한 방법들이 고찰되었다.

• Journal of Auto-vehicle Safety Association
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• v.12 no.2
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• pp.27-32
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• 2020

This paper presents steering system requirements to ensure the stabilized lateral control of autonomous driving vehicles. The two main objectives of a lateral controller in autonomous vehicles are maintenance of vehicle stability and tracking of the desired path. Even if the desired steering angle is immediately determined by the upper level controller, the overall controller performance is greatly influenced by the specification of steering system actuators. Since one of the major inescapable traits that affects controller performance is the time delay of the steering actuator, our work is mainly focused on finding adequate parameters of high level control algorithm to compensate these response characteristics and guarantee vehicle stability. Actual vehicle steering angle response was obtained with Electric Power Steering (EPS) actuator test subject to various longitudinal velocity. Steering input and output response analysis was performed via MATLAB system identification toolbox. The use of system identification is advantageous since the transfer function of the system is conveniently obtained compared with methods that require actual mathematical modeling of the system. Simulation results of full vehicle model suggest that the obtained tuning parameter yields reduced oscillation and lateral error compared with other cases, thus enhancing path tracking performance.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.123-124
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• 2015

본 논문에서는 동기전동기(PMSM: Permanent Magnet Synchronous Motor)의 고정자 형상 변화를 통한 코깅토크(Cogging Torque)와 토크리플(Torque Ripple)저감에 대해 다루고자 한다. 고정자의 치의 두께와 길이에 변화를 주면서 FEM(Finite Elements Method)기반의 성능분석을 실시하여 각 형태에 대한 평균토크, 토크리플, 코깅토크를 분석, 비교해보았다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.10
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• pp.1923-1929
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• 2009

The design of SPMSM(surface mounted permanent magnet synchronous motor) has been performed to reduce cogging torque and torque ripples. In general, cogging torque and torque ripples are affected by the shapes of teeth width, yoke depth, magnet pole arc, etc. Particularly, the minimum design point of cogging torque and torque ripples are different so that the design of SPMSM should be done to compromise both of them for precision application. In this paper, the design of PMSM for EPS(electric power steering) system is performed to verify the validity, and the design characteristics versus teeth width, yoke depth, and magnet pole arc are investigated in order to find out the minimum point of cogging torque and torque ripples. In addition, skew of PM is applied for cogging torque reduction.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.10
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• pp.1403-1407
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• 2013

This paper presents the method to calculate the motor parameters considering skew in EPS Interior Permanent Magnet Synchronous Motor (IPMSM). The skew is applied to stator or rotor by general technology used for design of reducing noise and vibration in motor. The characteristics analysis of motor including the skew is mostly used by 3D Finite Element Analysis (FEA), though, this analysis is a very time-consuming to perform. Besides, The reliability lacks due to the considerable change of motor characteristics according to the number of elements in 3D FEA. However, analysis time and effort can be saved by characteristic analysis considering skew using 2D FEA. Therefore, in this paper, a quick and accurate method for the calculations of motor parameters considering skew is suggested. The proposed method is verified by the comparison of calculated and experimental results.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.904-905
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• 2011

본 논문에서는 기존의 EPS(Electric Power Steering) 시스템에 IPMSM을 적용하고 속도 및 위치를 검출하기 위하여 Magnetic Position Sensor를 사용하였다. 이�� Magnetic Position Sensor의 신호는 정현파의 출력을 갖지만 고조파의 성분으로 인하여서 파형이 왜곡되고 이러한 파형의 왜곡으로 인해 위치 검출의 오차를 갖게 된다. 본 논문에서는 이러한 오차를 줄이기 위하여 다구찌 기법과 3차원 유한요소법(3D FEM)을 사용하여 고조파를 저감시킬 수 있도록 여러 변수를 변화하여서 최적의 설계를 통하여 실제 실제 센서 출력과 비교하여 자동차 산업 전반에 기여 하고자 한다.