A Safe Robot Arm with Safe Joints and Gravity Compensator

최동은,최준호,조창현,박신석,강성철 제어·로봇·시스템학회 2013 International Journal of Control, Automation, and Vol.11 No.2

This study presents a robot arm equipped with safe joints and multi DOFs gravity compensators. The safe joint, also referred to as “Spring-clutch”, is simple passive mechanism that consist of a spring, a cam, and a joint torque sensor. When the torque applied is lower than a pre-set threshold, the Spring-clutch serves as a rigid joint between the input and output. When the applied torque exceeds the threshold, the Spring-clutch is released and is free to rotate like a revolute joint, which significantly re-duces the collision force to avoid damage to the robot, as well as to humans. In addition, a compact joint torque sensor is installed in the Spring-clutch to measure the torque at the joint. Also, the analysis of energy and torque shows that the proposed mechanism can function as a gravity compensator capable of static balancing. Since joint torques vary in accordance with the pose of a manipulator (i.e., rotation angles), a Spring-clutch with a constant threshold torque cannot always guarantee the maximum collision torque in some poses of a manipulator. To overcome this limitation, a gravity compensator is adopted to eliminate the gravitational torque. In this research a bevel gravity compensator is applied which can perform static balancing completely. This paper describes the design principles and fabrication of the safety mechanisms and the robot arm.

텍스트마이닝을 활용한 디자인창업 관련 연구 동향 분석 - 1999년부터 2020년까지 국내 연구를 중심으로-

최동은 한국디자인트렌드학회 2022 한국디자인포럼 Vol.27 No.1

Background A comprehensive understanding of the characteristics and trends of existing studies is essential in order to specialize and systematize the field of design entrepreneurship that has grown through the interchange with other disciplines. This study aims to seek an understanding of the characteristics of the studies on design entrepreneurship and their major research topics for the last 22 years through the analysis of the research trends on design entrepreneurship in South Korea. Methods A text mining technique was used to analyze the research topics related to design entrepreneurship from 1999 to 2020. The research subjects were 334 academic research papers and theses that were found in the RISS, a research paper search site, with design entrepreneurship and design startup as keywords. Result The analysis showed that the studies on design entrepreneurship have been conducted focusing on the topics that have been traditionally studied in the fields of venture businesses and design management, and those that have recently been attracting attention in the field of design entrepreneurship. In some topics, segmentation and diversification were observed. Conclusion This study is significant in that it identifies the research topics and trends in the field of design entrepreneurship and analyzes the research trends using a text mining technique, which analyzes unstructured data. In addition, the study will provide researchers with an opportunity and direction to gain insight from an academic perspective in selecting a research topic that is different from existing ones. 연구배경 타 학문과의 교류를 통해 성장해온 디자인창업 분야를 보다 전문화하고 체계화하기 위해서는 기존 연구의 특성과 흐름에 대한 포괄적인 이해는 필수적이다. 이에 본 연구는 국내 디자인창업의 연구 동향 분석을 통하여 지난 22년간 디자인창업 분야에서 나타난 주요 연구주제와 그 특성에 대한 이해를 도모하고자 한다. 연구방법 본 연구에서는 텍스트마이닝 기법을 사용하여 1999년부터 2020년까지의 디자인창업 관련 연구주제를 분석하였다. 연구자료는 논문검색 DB 사이트 RISS에서 디자인창업, 디자인 스타트업을 검색하여 도출되는 학술논문과 학위논문 334편을 대상으로 하였다. 연구결과 분석결과 디자인창업 분야에서는 벤처창업과 디자인경영 분야에서 전통적으로 연구해온 주제와 시대별로 디자인창업 분야에서 주목받고 있는 새로운 주제들을 중심으로 연구가 진행되고 있었다. 또한 일부 주제에서는 세분화, 다각화 현상이 나타났다. 결론 본 연구는 디자인창업 분야의 연구주제와 동향을 파악하였으며, 비정형 데이터를 분석하는 텍스트마이닝 방법을 활용하여 연구 동향을 분석했다는 점에도 그 의의가 있다. 또한 연구자들에게 기존 연구와 차별성 있는 연구주제를 탐색하는데 학술적 맥락에서 통찰할 수 있는 기회와 방향성을 제공할 것이다.

EG Ejector를 이용한 에너지 절감 방안

최동은,Choe, Dong-Eun 에너지절약전문기업협회 2008 esco Vol.53 No.-

우리에게 익숙한 폴리에스터나 나일론(폴리아마이드)은 2개 이상의 단위체를 결합하여 만든 고분화 화합물이며 이들을 만드는 과정을 중합반응이라고 한다. 예를 들면 폴리에스터의 경우, PTA(Purified Telephtal Acid)와 Ethylene Glycol을 약 $280^\circC$의 고온과 0.4torr 정도의 진공에서 합성해 만들어 진다. 이 반응에 필요한 진공 조건을 유도하기 위해 Ejector가 필요한데 우리나라의 화학 섬유 공장에서는 주로 증기를 이용한 Ejector를 사용하고 있다.

Analysis of Japanese Women's Abdominal Shapes Using the Three Dimensional Human Body Model

최동은,나카무라 켄스케,쿠로가와 타카오,Choi, Dong-Eun,Nakamura, Kensuke,Kurokawa, Takao The Korean Fiber Society 2011 한국섬유공학회지 Vol.48 No.1

Female body parts, such as breasts, the abdomen, and hips, have three-dimensional shapes that are important for both the ergonomics and beauty of clothing design. The purpose of this study is the three-dimensional analysis and classification of women's abdomens using a geometric model of a three-dimensional human body. The geometric model used in this study is a method of modeling the body surface data acquired by three-dimensional measurements. It describes the shape of the body surface by means of control points on a cylindrical bi-cubic B-spline surface normalized using reference points on the body surface. The three-dimensional body shape measurement data were derived from 556 Japanese females aged 19 to 63. After finding the control points that determine the abdominal shape by applying the measurement data of each three-dimensional human body to the developed geometric model, 99 three-dimensional coordinates of the abdominal shape control points, comprising $99{\times}3$ (x, y, z coordinates)=297 coordinates, were obtained. The method used for analysis was the principal components method based on the variance-covariance matrix. The cumulative contribution rate from the first principal component to the fourth principal component was 82%, indicating that abdominal shapes can be described accurately by these four components. The I st component describes the abdominal protrusion and waist thickness. The 2nd component describes the longitudinal length and crosswise radius of the abdomen. The 3rd component indicates the degree of slimming and skin fold droop. The 4th component describes the lower abdomen droop level and the upper abdomen swelling level.

몸살 외 1편

최동은 고요아침 2008 열린시학 Vol.13 No.2

Design of Safe Joint with Variable Threshold Torque

최동은,조창현,이우섭,Seong Hun Hong,강성철,이형철 한국정밀공학회 2014 International Journal of Precision Engineering and Vol. No.

This study presents a passively variable threshold torque Spring-Clutch (PVSC). When human beings and robots work together asin the service robot example, physical safety of the former should be guaranteed. A passive mechanism is usually preferred becauseof its high reliability and fast response to collision. The PVSC comprises the Spring-Clutch mechanism (in that a spring and cam areutilized for generating threshold torque), and an adjuster (an additional cam and lever mechanism to adjust the threshold torque). It functions as a rigid joint between the input and output. However, when the applied torque exceeds the threshold value, the PVSCjoint is fully released and becomes freely rotatable to guarantee safety during contact. The threshold torque is passively adjustedaccording to the gravitational torque and, therefore, a constant releasing torque is maintained for all joint rotation angles. Thethreshold torque of the PVSC increases (or decreases) in response to the variation in the deflection of the spring (achieved by usingthe adjuster) according to the rotation angle (or gravitational torque). Experiments were performed and the PVSC was implementedin the second joint of the SS-Arm IV.

유럽 탐방을 통한 벌 중심 연구체계 국내 적용 방안

최동은,박철진,신정윤,양지혜 한국환경정책학회 2014 한국환경정책학회 학술대회논문집 Vol.2014 No.10

프탈로시아닌 박막을 이용한 가스센서

최동한 청주대학교 산업과학연구소 1999 産業科學硏究 Vol.17 No.1

The phthalocyanine thin film gas sensors were fabricated and their gas sensing characteristcs were investigated. The lead phthalocyanine(PbPc) thin films showed the highest sensitivity to lppm NO₂ in air at an operating temperature of 190 C. The sensitivity of the lead phthalocyanine thin films to lppm NO₂ gas was 70% at an operating temperature of 190℃. The sensor s output reached the saturation value after 30seconds and recovered after 120seconds.

이중 지연선 SAW Gas Sensor의 제작 및 특성

최동한 청주대학교 산업과학연구소 1996 産業科學硏究 Vol.14 No.-

A surface acoustic wave (SAW) NO_(2) gas sensor has been designed, fabricated and tasted. The sensor consists of SAW dual delay lines was fabricated on a single LiTaO_(3) substrate using photolithographic technique. Each delay line was configured as an oscillator. The propagation path of one delay line was coated with a sublimated film of lead phthalocyanine (PbPc), while the other was uncoated and used as a stable reference.

γ-Fe_(2)O_(3)의 미세구조 분석

崔東漢 청주대학교 산업과학연구소 1992 産業科學硏究 Vol.10 No.-

The microstructure of γ-Fe₂O₃ which is well known for as hydrocarbon gas sensitive material, has been investigated with Mossbauer spectroscopy. The Mo¨ssbauer paramenters, such as IS, QS, and MHF, and the states of iron in the γ-Fe₂O₃ were analyzed at room temperature and 350℃. From the experimental results, there are only Fe³ ions in the r-Fe₂O₃ and Fe² ions were not observed. The MHF at room temperature were 496 KOe(A-site) and 513 KOe(B-site), respectively. And the value of MHF at the temperature of 350℃ decreased to 382 KOe(A-site) and 413 KOe(B-site) that is due to the magnetic transition effects and disordered magnetic spin. The absorption ratio was decreased at 350℃ owing to lattice vibration in the γ-Fe₂O₃. The value of IS at 350℃ was slightly decreased and that could be attributable to second doppler effects caused by the temperature difference between γ-ray source and absober. And the values of IS and QS suggest that only Fe+³ ions are exist in the γ-Fe₂O₃ at room temperature and 350℃.