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A study on TAS sensor failure detection algorithm for redundant system based EPS system
Sangwoo Jeong(정상우),Daesung Kim(김대성),Jonghyun Pyo(표종현),Jinhwan Lee(이진환) 한국자동차공학회 2022 한국자동차공학회 학술대회 및 전시회 Vol.2022 No.11
The redundant system serves to increase the robustness against failure by operating the two or multiple identical systems simultaneously. In particular, it became one of the widely applied method to increase functional safety in the automobile industry as automobiles are being changed from mechanical to electronic. However, even two identical systems or sensors are used simultaneously, it can be known that a failure has occurred when the two output values are different, but there is a limitation in that it is difficult to determine which of the two is the result of normal operation. This limitation results in degrading overall system performance or even suspend the system operation. To solve this problem, a method using three or more identical systems is also used, but it is disadvantageous in terms of cost and system complexity. The research objective of this paper is to maintain the steering assistance performance of Electronic Power Steering system using the two steering angle sensors by determining which sensor is operating normally when one sensor has faults. In this paper, a normally operating sensor is determined using the steering angle estimated by bicycle model based Extended Kalman Filter. In addition, a fault determination algorithm was applied to increase the robustness for the estimation result. The performance of the proposed algorithm is shown in experimental result that steering assistance can be maintained in case of one of the two sensor has abnormal operation.
무가선 트램의 주행안전성 향상을 위한 선로인식기반 충돌 판단 시스템
박승진(Seungjin Park),정상우(Sangwoo Jeong),이민철(Minchul Lee),선우명호(Myoungho Sunwoo) 한국철도학회 2016 한국철도학회 학술발표대회논문집 Vol.2016 No.10
트램은 일반철도와는 달리 선로상에 보행자와 같은 돌발 장애물이 나타날 수 있는 주행 환경을 가진다. 기존에 개발되고 있는 레이더 기반 충돌 판단 시스템의 경우 센서 특성상 사람을 인식하기 어렵고 횡 방향 운동 추정에 한계가 있다. 이러한 한계를 극복하기 위해 이 연구에서는 카메라와 레이저스캐너의 융합정보 기반 충돌 판단 시스템을 제안한다. 제안된 시스템은 단안 카메라 기반 선로 인식 부분 및 인식 정보와 레이저스캐너 기반 충돌가능물체 거동 예측 부분으로 구성된다. 해당 시스템은 실제 트램이 주행환경에서 취득한 데이터 기반으로 검증 되었다. 본 연구에서 제안한 선로 인식 부분은 선로에 인식에 적합한 필터를 설계해 보다 강건한 선로 인식을 할 수 있으며 충돌가능물체에 대한 예측을 통하여 효율적인 충돌 판단을 가능하게 하였다. Unlike general trains, a wireless tram’s driving environment carries the risk of people or vehicles suddenly entering into its rails. Previous systems for trams detected objects using radar. However, radar-based collision risk assessment systems were found to have several disadvantages. For instance, low-cost radar systems cannot detect people and have difficulty in estimating lateral motion. To overcome such issues, this paper will propose a camera and laser scanner convergence-based collision risk assessment system. The proposed system consists of a monocular camera-based rail detection module and a detected rail and object-based behavior recognition module. The applicability of this system was evaluated based on logged sensor data-based simulations. The proposed system in this paper effectively detects rails by removing lanes from its detection range and assesses the collision risk efficiently through the prediction of collisional objects.
접촉 점화성 추진제의 충돌형 혼합 특성 연구 동향 조사
김규섭(Kyu-Seop, Kim),김예현(Yehyun Kim),정상우(Sangwoo Jung),정준영(Junyeong Jeong),권세진(Sejin Kwon) 한국추진공학회 2019 한국추진공학회 학술대회논문집 Vol.2019 No.5
접촉 점화 추진제 특성을 활용한 추력기는 간단한 시스템 구조와 점화의 높은 신뢰성을 기반으로 고고도, 우주 환경에서의 적용되어 왔다. 미국을 위시한 선진국의 경우 사산화질소/아민 계열의 추진제의 충돌 혼합 특성을 1960년대 이후로 심도 깊은 연구를 진행하고 있으며 최근 차세대 접촉 점화 추력기 역시 고성능화, 경량화 측면에서 활발한 연구개발을 수행하고 있다. 본 논문에서는 접촉 점화성 추진제의 충돌형 혼합 특성과 반응성 유동 분리(Reactive Separation Flow), 간헐적 폭발(Popping)의 충돌 혼합 시 발생할 수 있는 연소 불안정성에 대한 연구 동향을 조사하고 요약하였다. The hypergolic thruster has been extensively researched and applied on spacecraft propulsion based on simple system and high reliability of ignition. Research on impingement characteristics of N2O4/Amine has been profoundly carried out since the 1960s in advanced countries, especially the US. Recently enhancement of advanced hypergolic thruster using MON/MMH is currently planned by NASA in terms of improving compactness and high performance. In this work, technical trends of mixing of hypergolic propellant and its combustion instabilities such as reactive separation flow and poping were investigated.
신창주(Changjoo Shin),홍진숙(Chinsuk Hong),정의봉(Weuibong Jeong),정상우(Sangwoo Jeong) 한국소음진동공학회 2010 한국소음진동공학회 학술대회논문집 Vol.2010 No.10
This paper reports active control of clamped beams using acceleration feedback controllers (AF). The equations of motion of clamped beam under force and moment pairs were derived and the equations of AF controllers were formulated. The effect of the parameters - gain and damping ratio - of the AF controllers on the open loop transfer function was investigated mainly in terms of the system stability. Increasing the gain of the AF controller tuned at a mode, the magnitude of the open loop transfer function is increased at all frequencies. The increase of the damping ratio of the AF controller leads to decrease the magnitude of the open loop transfer function and modifies its phase characteristics to be more stable. Three AF controllers connected in parallel were then proposed. Each AF controller is tuned at the 2nd, 3rd and 4th modes, respectively. Their parameters were determined to remain the system to be stable based on the results of the parametric study. A significant reduction in vibration at the 3 modes can be obtained.