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나종호(Jongho Na),이재우(Jaewoo Lee),강오성(Ohsung Kang) 한국자동차공학회 2011 한국자동차공학회 학술대회 및 전시회 Vol.2011 No.11
BEV (Battery Electric Vehicle) is not currently launching and applied at domestic market .In spite of that, it is getting important to make a vehicle which has a performance such as high fuel efficiency or of environmental protection. For those reasons, it is expected for vehicles to be developed. UCCB (Underhood Cross-Car Beam) ,one of main components for Electric Vehicle, is sustaining and fixing a some of parts(HVAC (Heating Ventilating and Air Conditioning)) and Electric Modules Nowadays It is widely going on a research to evaluate a strength and durability in all over the world. Strength and performance of structure are pre-expected by using a Fatigue simulation through FEA (Finite Element Analysis) to reduce a developing time and cost. Also, it can be compared with real and virtual test result. As a result of this paper, it is systematized how to set up an analysis of UCCB and proved it with reliability.
SMT 장비의 동작 상태 분류를 위한 음향 스펙트럼 비교에 관한 연구
나종호(Jongho Na),신휴성(Hyusoung Shin),박영현(Younghyun Park),윤일동(Ildong Yun) 한국산학기술학회 2021 한국산학기술학회논문지 Vol.22 No.11
SMT(Surface Mount Technology) 장비는 PCB(Printed Circuit Board) 기판에 각종 소형 전자 부품을 장착하고 납땜하는 자동화 장비를 의미한다. SMT 장비를 주기적으로 유지보수하지 않으면 장비의 고장이 발생하여 막대한 경제적 손실을 가져올 수 있으므로 SMT 장비의 동작상태 진단은 매우 중요하다. 본 논문에서는 데이터 전처리 단계에서 신호처리 기법인 시간-평균 스펙트럼의 특징 추출을 위한 새로운 기법을 제안한다. 데이터는 학습데이터와 실험데이터로 구분되며, 학습데이터를 이용하여 각 동작(소자 마운트, 실린더 에어 분출, 내부 부품 흔들림, 정지)의 정상신호를 정의한다. 그리고 시간-평균 스펙트럼 특징을 유사도 비교 기법(Histogram Intersection, KL-Divergence, Earth Mover Distance)으로 정상 임계치 범주에 속하는지 판단한다. 마지막으로, 모든 동작의 임계치 범주에 속하지 않는다면 새로운 동작이 발생하였고 비정상신호라 판단하는 시스템을 제안한다. 실험을 통해 검증 결과, 제안한 유사도 비교방법이 상대적으로 적은 학습시간으로 인공신경망과 유사한 분류 성능을 얻을 수 있다. Surface Mount Technology (SMT) devices, referred to as automated equipment, are used to mount and solder various small electronic parts of PCB boards. If the SMT equipment is not regularly maintained, the equipment may malfunction, leading to enormous economic damage. Thus, diagnosing the operating state of SMT devices is very important. In this paper, we propose a new technique for feature extraction of time-averaged spectra, which is a signal processing technique in the data preprocessing stage. The data is split into training data and testing data, and the normal signal of each operation (Element Mount, Cylinder Air Blowout, Oscillation, Stop) is defined using the learning data. Then, the signal is examined to see whether the time-averaged spectral feature belongs to the normal threshold range by using a similarity comparison technique (Histogram Intersection, KL-Divergence, Earth Mover Distance). Lastly, if the signal does not belong to the threshold range of all motions, a new motion is said to have occurred and a proposed system decides that the signal is abnormal. As a result of the verification through experiments, the proposed similarity comparison method was able to obtain classification performance similar to that of an artificial neural network with relatively less learning time.
[기술논문] 제한된 이산정보를 이용한 로어컨트롤암의 신뢰성 기반 최적설계
장준용(Junyong Jang),나종호(Jongho Na),임우철(Woochul Lim),박상현(Sanghyun Park),최성식(Sungsik Choi),김정호(Jungho Kim),김용석(Yongsuk Kim),이태희(Tae Hee Lee) 한국자동차공학회 2014 한국 자동차공학회논문집 Vol.22 No.2
Lower control arm (LCA) is a part of chassis in automotive. Performances of LCA such as stiffness, durability and permanent displacement must be considered in design optimization. However it is hard to consider different performances at once in optimization because these are measured by different commercial tools like Radioss, Abaqus, etc. In this paper, firstly, we construct the integrated design automation system for LCA based on Matlab including Hypermesh, Radioss and Abaqus. Secondly, Akaike information criterion (AIC) is used for assessment of reliability of LCA. It can find the best estimated distribution of performance from limited and discrete stochastic information and then obtains the reliability from the distribution. Finally, we consider tolerances of design variables and variation of elastic modulus and achieve the target reliability by carrying out reliability-based design optimization (RBDO) with the integrated system.
Safety Cage Homologation 위한 설계, 해석 및 제작
박민근(Mingeun Park),나종호(Jongho Na),박준규(Junegyu Park) 한국자동차공학회 2016 한국자동차공학회 학술대회 및 전시회 Vol.2016 No.11
Safety is very important factor in Racecar. So Roll Cage for Racecar has been developed and optimized using FEA or CAE program. But In this Country, Many Motor Sports Teams have not been proceeding this process. In order for Motor Sports in Korea to improve, Vehicle Engineering is very important factor. So In this paper, we introduce easy design and analysis for many Motor Sports Team in Korea. Also we verified our i30 Racecar Roll Cage’s safety and stiffness using CAE program. And we compared Hyundai WRC i20 Safety Cage’s stiffness.
제한된 이산정보를 이용한 엔진 크래들의 신뢰성 기반 최적설계
임우철(Woochul Lim),나종호(Jongho Na),장준용(Junyong Jang),박상현(Sanghyun Park),김정호(Jungho Kim),이태희(Tae Hee Lee) 한국자동차공학회 2013 한국자동차공학회 학술대회 및 전시회 Vol.2013 No.11
To achieve mass reduction and performance improvement, design optimization has been studied in automotive engineering. Recently, stochastic design optimization methods are used to calculate not only the performance but also a probability of the performance. Reliability-based design optimization (RBDO) is one of the stochastic design optimization methods. In RBDO, by considering stochastic information of input variables, the reliability of the performance can be estimated. In this paper, we adopt the RBDO to design an engine cradle with limited discrete information from tolerance of a panel of an engine cradle. With the stochastic information of the input variables, the reliabilities of the performance such as stiffness, life and permanent displacement are estimated by the reliability analysis using Akaike information criterion (AIC). AIC can find the best estimated distribution of the performance from limited discrete information and then estimate the reliability from the distribution. Finally, we can reduce the mass and satisfy the target reliabilities of the performances of the engine cradle.
횡 방향 굽힘 강성 및 내구 성능을 고려한 맥퍼슨 스트럿의 경량 최적 설계에 대한 연구
김주영(Jooyoung Kim),나종호(Jongho Na),이재우(Jaewoo Lee),김용석(Yongsuk Kim) 한국자동차공학회 2014 한국자동차공학회 학술대회 및 전시회 Vol.2014 No.11
Recently, development of light-weight vehicle is the most important issue in the automobile industry to improve fuel efficiency, vehicle performance and cost reduction. So, mass or weight reduction is being tried in the vehicle body(BIW) as well as suspension components. This paper will discuss iterative optimization strategy to minimize the mass of MacPherson strut suspension while meeting the lateral bending stiffness and durability requirements. The focus of this study is to find key control factors for weight reduction of MacPherson strut considering lateral bending stiffness and durability performance. This process of optimization study consists of three steps. Firstly, to comprehend the current status of lateral bending stiffness of competitors" MacPherson strut, the strut bending test is performed and static stiffness analysis for our product is conducted with qualified test correlation model. In the second step, static stiffness analysis is conducted with selected design variables to find key factors of weight reduction. And then, fatigue & pothole analysis for the standard loadcases are performed to meet the durability target based on former result of the steps. As a result of the optimization study, we proposed the key control factors and optimum light-weight design model affecting strut lateral stiffness, durability performance.
제한된 정보를 이용한 로어컨트롤암의 신뢰성 기반 최적설계
장준용(Junyong Jang),나종호(Jongho Na),임우철(Woochul Lim),박상현(Sanghyun Park),최성식(Sungsik Choi),김정호(Jungho Kim),김용석(Yongsuk Kim),이태희(Tae Hee Lee) 한국자동차공학회 2013 한국자동차공학회 부문종합 학술대회 Vol.2013 No.5
Lower control arm (LCA)is a part of chassis in vehicles. Performances of LCA such as stiffness, durability and permanent displacement have to be considered in design optimization. However it is hard to consider different performances at once in optimization because these are measured by different tools like Radioss, Abaqus, etc. In this paper, firstly, we construct the integrated design automation system for LCA based on Matlab including Hypermesh, Radioss and Abaqus. Secondly, Akaike information criterion (AIC) is used for assessment of reliability of LCA. It can find the best estimated distribution of performance from limited stochastic information and then obtain the reliability from the distribution. Finally, we consider tolerances of design variables and variation of elastic modulus and obtain performances of target reliability by performing reliability-based design optimization (RBDO) with the integrated system.