Development and performance evaluation of lateral control simulation-based multi-body dynamics model for autonomous agricultural tractor

손모아,전현호,백승윤,백승민,김완수,김연수,신대윤,임류갑,김용주 충남대학교 농업과학연구소 2023 Korean Journal of Agricultural Science Vol.50 No.4

In this study, we developed a dynamic model and steering controller model for an autonomous tractor and evaluated their performance. The traction force was measured using a 6-component load cell, and the rotational speed of the wheels was monitored using proximity sensors installed on the axles. Torque sensors were employed to measure the axle torque. The PI (proportional integral) controller’s coefficients were determined using the trialerror method. The coefficient of the P varied in the range of 0.1 - 0.5 and the I coefficient was determined in 3 increments of 0.01, 0.05, and 0.1. To validate the simulation model, we conducted RMS (root mean square) comparisons between the measured data of axle torque and the simulation results. The performance of the steering controller model was evaluated by analyzing the damping ratio calculated with the first and second overshoots. The average front and rear axle torque ranged from 3.29 - 3.44 and 6.98 - 7.41 kNm, respectively. The average rotational speed of the wheel ranged from 29.21 - 30.55 rpm at the front, and from 21.46 - 21.63 rpm at the rear. The steering controller model exhibited the most stable control performance when the coefficients of P and I were set at 0.5 and 0.01, respectively. The RMS analysis of the axle torque results indicated that the left and right wheel errors were approximately 1.52% and 2.61% (at front) and 7.45% and 7.28% (at rear), respectively.

Two Distinct Subsets Are Identified from the Peritoneal Myeloid Mononuclear Cells Expressing both CD11c and CD115

손모아,나혜영,류슬혜,최완호,인현주,신현수,박지수,심다희,신성재,박채규 대한면역학회 2019 Immune Network Vol.19 No.3

To this date, the criteria to distinguish peritoneal macrophages and dendritic cells (DCs) are not clear. Here we delineate the subsets of myeloid mononuclear cells in the mouse peritoneal cavity. Considering phenotypical, functional, and ontogenic features, peritoneal myeloid mononuclear cells are divided into 5 subsets: large peritoneal macrophages (LPMs), small peritoneal macrophages (SPMs), DCs, and 2 MHCII+CD11c+CD115+ subpopulations (i.e., MHCII+CD11c+CD115+CD14−CD206− and MHCII+CD11c+CD115+CD14+CD206+). Among them, 2 subsets of competent Ag presenting cells are demonstrated with distinct functional characteristics, one being DCs and the other being MHCII+CD11c+CD115+CD14−CD206− cells. DCs are able to promote fully activated T cells and superior in expanding cytokine producing inflammatory T cells, whereas MHCII+CD11c+CD115+CD14−CD206− cells generate partially activated T cells and possess a greater ability to induce Treg under TGF-β and retinoic acid conditions. While the development of DCs and MHCII+CD11c+CD115+CD14−CD206− cells are responsive to the treatment of FLT3 ligand and GM-CSF, the number of LPMs, SPMs, and MHCII+CD11c+CD115+CD14+CD206+ cells are only influenced by the injection of GM-CSF. In addition, the analysis of gene expression profiles among MHCII+ peritoneal myeloid mononuclear cells reveals that MHCII+CD11c+CD115+CD14+CD206+ cells share high similarity with SPMs, whereas MHCII+CD11c+CD115+CD14−CD206− cells are related to peritoneal DC2s. Collectively, our study identifies 2 distinct subpopulations of MHCII+CD11c+CD115+ cells, 1) MHCII+CD11c+CD115+CD14−CD206− cells closely related to peritoneal DC2s and 2) MHCII+CD11c+CD115+CD14+CD206+ cells to SPMs.

색각이상자를 위한 색채배색 개선 방안 연구 - 컬러유니버설디자인 측면에서 산업안전표지 중심으로 -

손모아 ( Son Mo-a ),손원준 ( Son Wonjun ) 한국디자인트렌드학회 2016 한국디자인포럼 Vol.53 No.-

연구배경 산업안전표지에서의 컬러는 사고 위험에 대한 정보를 즉각적으로 전달하는 시각 요소로서 정상색각인은 물론 색각이상자들도 인지 가능하도록 설계되어야 한다. 하지만 기존 산업안전표지의 컬러는 고채도 · 고명도의 원색을 사용하고 있어, 3가지 이상의 색으로 배색하여 사용할 경우 시인성이 매우 떨어지는 문제점을 안고 있다. 특히 색각이상자들이 사용하기에 큰 어려움을 안고 있는 실정이다. 이에 본 연구에서는 다양한 개인의 색채 지각 능력을 수렴할 수 있는 산업안전표지의 색채배색 연구모형을 제시하고자 한다. 연구방법 국내의 산업안전표지를 컬러를 중심으로 분류하고 이에 대하여 정상색각인과 색각이상자 각각이 인지하는 표지의 시인성을 알아보았다. 이를 기준으로 시인성과 관련된 표지의 시각요소를 도출하고, 이 분석 결과를 토대로 색채배색 연구모형을 개발하였다. 연구결과 색각이상자의 시각적 특성에 따른 산업안전표지의 시인성을 분석한 결과 3가지 이상의 색으로 배색한 표지의 경우 고명도와 고명도, 저명도와 저명도가 충돌해 콘트라스트가 낮아져 색상 간의 구분이 어려운 것으로 분석되었다. 이에 표지의 시인성을 개선할 수 있는 색채 간 명도 조정 방안에 대한 연구모형을 제시하였다. 결론 본 논문에서는 색각이상자들의 색지각 오차 범위를 줄이기 위한 색채배색 개선 방안을 제시하였다. 현재는 컬러 조정에 필요한 요소들을 수식화하는 후속연구를 진행 중에 있어, 산업안전표시 이외의 다양한 산업군에서 좀 더 용이하게 활용 가능할 것으로 기대한다. Background The colors used for industrial safety signs are visual elements which instantly convey information regarding dangers resulting from accidents, and therefore must be carefully selected and determined considering the diversty of individuals`color recognizing capabilities. Acoordingly, industrial signs currently being used are required to use prominent primary colors, but in cases where these colors are used together the contrast between the colors is reduced, making the signs harder to read, especially for those with color blindness. Therefore, this study suggests color Arrangement guidelines (manuals) for industrial safety signs fit for persons with color blindness. Methods This study analyzed the visibility of industrial safety signs recognized by persons with color blindness based on a color vision defiency simulation. Based on these results, a famework for developing industrial safety signs which persons with color blindness can read was deduced. Result As a result, the brightness difference was determined to be the element which affected visibility the most based on researching the visibility of domestic industrial safety signs` according to the visual characterstics of color blind individuals. From this, a research model for determinary the adjustments to brightness which can increase the the readability of industrial safety signs was produced. Conclusion This study suggests a color development model for reducing the range of error in the color perception of color blind persons. Further studies studies modifying necessary elements of color adjustments are currently in progress, and it is anticipated that this study will be more easily utilized in diverse industrial areas.

자율주행 트랙터 횡방향 제어 시뮬레이션 모델 성능평가

손모아(M. A. Son),전현호(H. H. Jeon),백승민(S. M. Baek),백승윤(S. Y. Baek),강영선(Y. S. Kang),김용주(Y. J. Kim) 유공압건설기계학회 2023 유공압건설기계학회 학술대회논문집 Vol.2023 No.5

Hepatoprotective effect of Hippocampus abdominalis hydrolysate

손모아 ( Moa Son ),문준영 ( Jun Young Moon ),박상규 ( Sanggyu Park ),조문제 ( Moonjae Cho ) 한국응용생명화학회 2016 Journal of Applied Biological Chemistry (J. Appl. Vol.59 No.3

Recently, liver damage contributes to big percentage of the morbidity and mortality rates worldwide. Excessive intake of alcohol is one of the major causes of liver injury. When liver injury is repeated and becomes chronic, it leads to development of fibrosis and cirrhosis. In the liver, TGF-β is a profibrogenic cytokine, which participates in various critical events cause liver fibrosis. Seahorse (Hippocampus abdominalis) is a common traditional Chinese medicine and has been widely used for centuries. Seahorse has been known to have a variety of bioactivities, such as anti-oxidant, anti-fatigue, and anti-tumor. Peptide is one of the main compounds of seahorse. In this study, we isolated enzymatic hydrolysate from seahorse H. abdominalis by alcalase hydrolysis and investigated the effect of the hydrolysate on liver injury. In the present in vitro studies, the hydrolysate increases cell viability of Chang cells and protects Huh7 cells from ethanol toxicity. In addition, the hydrolysate inhibits TGF-β-induced responses. In vivo studies show that the pretreatment of hydrolysate reduces alcohol-induced increases of serum Glutamic oxaloacetic acid transaminase and Glutamic pyruvate transaminase activities and increases liver weight and body weight. These results suggest that seahorse may have a hepatoprotective effect.

쟁기 경운 작업 부하 분석을 통한 3점히치 동역학 시뮬레이션 모델 개발

손모아 ( Mo-a Son ),백승윤 ( Seung-yun Baek ),백승민 ( Seung-min Baek ),전현호 ( Hyeon-ho Jeon ),이준호 ( Jun-ho Lee ),강영선 ( Young-sun Kang ),김용주 ( Yong-joo Kim ) 한국농업기계학회 2022 한국농업기계학회 학술발표논문집 Vol.27 No.2

The tractor performs agricultural operations in an uneven environment by attaching the implement to a 3-point hitch. Therefore, continuous load is generated on the 3-point hitch connected to the attachment and the tractor, result in fatigue and plastic failure. In this study, a dynamic simulation model was developed to predict the load occurring on the eyebolt of the 3-point hitch, which is the main damaged component. The development of the dynamics model was performed using the specifications of the 78 kW class tractor. Traction load of the 3-point hitch was measured by plow tillage operation. the average traction loads on the left and right sides of the lower link, and top link were approximately 8,099.97, 4,943.06, and 636.11 N, respectively. The simulation and measured average load of the left eyebolt were about 610.30 and 597.15 N, respectively. In the case of the right eyebolt, the simulation and measured average load of about 1,179.78, and 1,145.06 N, respectively. The simulation and measured load the error was similar accounting for about 2% on the left eyebolt and 3% on the right eyebolt. We plan to conduct damage analysis and reliability study in various agricultural operations.

농업용 트랙터의 가변형 3점 히치 유압 시뮬레이션 모델 개발

손모아 ( Mo-a Son ),전현호 ( Hyeon-ho Jeon ),백승민 ( Seung-min Baek ),백승윤 ( Seung-yun Baek ),이준호 ( Jun-ho Lee ),김용주 ( Yong-joo Kim ) 한국농업기계학회 2022 한국농업기계학회 학술발표논문집 Vol.27 No.1

현재 트랙터에 사용하고 있는 3점 히치는 작업기 탈부착 시 자유도가 낮고 조작이 어려워 작업기 교환에 많은 시간이 소요되기 때문에 이를 개선하기 위한 연구가 필요하다. 본 연구에서는 높이 및 폭 조절이 가능한 3점 히치를 개발하기 위해 시뮬레이션 모델을 개발하였으며, 제원에 따른 시뮬레이션을 수행하였다. 유압 시스템 해석은 상용 소프트웨어인 AMESim (Ver.: 16, lmagine S. A. company, France)을 사용하였다. 가변형 3점 히치 장치의 유압시스템 단품모델은 국내 중형 마력급 이상의 트랙터에서 사용하는 3점 히치(Category-Ⅲ) 의 제원을 참고하여 개발하였다. 유압 펌프의 토출 유량은 52.8 lpm(@2,200rpm)으로 설정하였으며, 농작업 조건을 반영하여 유압펌프의 회전속도는 일정하게 설정하였다. 유압 실린더의 피스톤 직경 및 스트로크 길이는 65, 115 mm로 설정하였으며, 3점 히치에 작용하는 수직 하중을 구현하기 위해 외력 적용이 가능한 실린더 모델을 활용하였다. 입력 신호 값은 작업기의 무게(800 kg)를 반영하여 지속적인 하중이 작용하도록 구성하였다. 3점 히치 장치의 시뮬레이션 해석은 승강 및 하강 조건에서 각각 수행되었으며, 펌프의 토출 유량 및 압력은 2 sec의 안정화 구간 이후 각각 27.2 MPa, 880 cc/s으로 나타났으며, 실린더 입력 단의 유량 및 압력은 각각 25.0 MPa, 880 cc/s으로 나타났다. 유압 펌프의 신뢰성 평가 기준은 85% 이상의 효율을 가진 모델을 기준으로 시뮬레이션 모델은 이를 만족하는 것으로 나타났다. 차후 연구에서는 추가 실린더를 구성하여 가변형 3점 히치 구현을 위한 연구를 수행할 예정이다.

수소연료전지 트랙터 기술 동향

손모아(Mo A Son),강영선(Young Sun Kang),김용주(Yong Joo Kim) 유공압건설기계학회 2023 드라이브·컨트롤 Vol.20 No.2

간암세포주 Huh7에서 Hepatitis B virus X protein에 의한 간섬유화

손모아 ( Mo A Son ),박상규 ( Sang Gyu Park ),조문제 ( Moon Jae Cho ) 한국응용생명화학회 2016 Journal of Applied Biological Chemistry (J. Appl. Vol.59 No.1

Hepatitis B virus infection can cause hepatic fibrosis leading to cirrhosis and hepat℃ellular carcinoma. However the mechanism remains poorly understood. In this study, we found that Hepatitis B virus X-protein (HBx) increases vimentin, fibronectin, slug, snail and NOX4 expression. Because NOX4- mediated reactive oxygen species can increase slug and snail, which can induce fibrosis, HBx may be a key regulator of hepatic fibrosis development via NOX4 induction.

Development of the Simulation Model for Tractor 3-Point Hitch using AMESim

M. A. Son(손모아),H. H. Jeon(전현호),S. M. Baek(백승민),S. Y. Baek(백승윤),J. H. Lee(이준호),Y. J. Kim(김용주) 유공압건설기계학회 2022 유공압건설기계학회 학술대회논문집 Vol.2022 No.06