• Transactions of the Korean Society of Mechanical Engineers
• /
• v.19 no.1
• /
• pp.38-44
• /
• 1995

We made a counter to measure the output of motor encoders for the motion error analysis of a CNC machining center, and have measured the dynamic characteristics and the position errors experimentally. Especially, we measured the radius errors for different feedrates and different radii when the CNC machining center performed a circular interpolation. We have also used an iterative learning method to reduce the radius errors and stick motion errors generated by the CNC machining center performing a circular interpolation. The results show that the proposed learning scheme can reduce the radius error and stick motion error significantly. The reduction of errors becomes more pronounced for higher feedrate and smaller radius.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.13 no.6
• /
• pp.15-22
• /
• 2014

With a conventional positioning apparatus, it is very difficult simultaneously to achieve desired driving ranges and precision levels at the sub-micrometer level. Generally, a lead screw and friction drive have been used as servo control systems. These have large driving ranges, and high-speed positioning is feasible. In this study, we present a global servo system controlled by a laser interferometer acting as a displacement measurement sensor for achieving positioning accuracy at the sub-micrometer level.

• Proceedings of the KIEE Conference
• /
• 2005.07c
• /
• pp.2351-2353
• /
• 2005

본 논문은 포장도로의 표면 상태를 고성능의 레이저 변위 센서를 사용하여 정밀하게 측정하고, GPS(Global Positioning System)를 사용하여 측정 위치 데이터를 획득하는 도로 표면 측정 장비 개발에 관한 논문이다. 본 연구에서는 전체 시스템을 설계하고, 차량 주행을 모사한 실험 모형을 제작하여 실내 실험을 실시하였으며, GPS 단말기로부터 실시간으로 위치 신호를 수신하여 도로면 데이터와 연동할 수 있도록 하였다. 그리고 평가 차량의 전면에 레일(rail)을 장착하여 레이저 변위 센서가 좌우로 왕복운동이 가능하도록 하였으며, 레일을 작동시킨 상태에서 도로면을 측정해 보았다. 실험 모형의 측정 곁과는 차량이 80km/h로 주행할 때 도로 표지 타이닝(tinning)의 폭 오차 3.24%, 깊이 오차 5%였다. 차량이 정지된 상태에서 레일을 작동시켜 요철을 측정하였을 경우 레일 방향에 대한 폭 오차는 0.07%였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.07b
• /
• pp.826-829
• /
• 2004

휴대폰이나 PDA등의 카메라 렌즈구동용으로 탑재 가능한 소형 압전 초음파 리니어 모터를 개발하였다. 선형 동작을 위한 구동력은 압전 세라믹과 1개 또는 2개의 세라믹으로 이루어진 uni- 또는 bimorph 형태의 압전 엑츄에이터에서 얻을 수 있다. 즉 초음파 영역의 펄스형태의 전압을 인가함으로써 정 또는 역의선형 운동과 인가하는 전압의 주기에 따라 정밀한 위치조절이 가능하고 제조공정이 용이하고 구조가 간단한 것을 특징으로 하는 모터이다. 본 연구에서는 소형 압전 초음파 리니어 모터의 원리와 동작특성을 고찰하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2009.05a
• /
• pp.615-618
• /
• 2009

2 axis Pan-tilt had been developed and utilize by vessel for the purpose of motion characteristic measurement. Besides, it also use to analysis structural design and fabrication. Test procedure had been created to produce most optimal design and to show the Nano Driving precision result performance.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2021.05a
• /
• pp.90-92
• /
• 2021

본 연구에서는 아마추어 또는 운동선수의 아이스하키 슈팅 훈련을 지원하는 IoT 시스템을 제안한다. 고성능 레이더 센서를 이용하여 퍽의 최대속도를 정밀하게 측정하고, 블루투스로 스마트폰에 전송된 퍽 속도 정보를 안드로이드 앱에서 간편하게 확인할 수 있으며, 측정 기록이 데이터베이스에 저장된다. 본 논문은 아이스하키 훈련을 보조하는 지능적인 코칭 시스템 개발을 위한 예비 연구로서, 실험결과는 레이더 센서 기술과 모바일 앱 기술을 통해 스포츠 훈련 보조 시스템 구현의 가능성을 보여준다.

• Journal of Navigation and Port Research
• /
• v.39 no.3
• /
• pp.173-178
• /
• 2015

In these days, the world has been increasing the development of various underwater vehicles such as ROVs (Remotely operated underwater vehicles) and AUVs (Autonomous underwater vehicles). And the importance of submarine's maneuverability is especially being emphasized. Therefore, accurate values of the derivatives in equations of motion are required to control motion of the submarines. The aims of the present study are to experimentally derive Hydrodynamic derivatives derived by the vertical planar motion mechanism (VPMM) model test, and to estimate vertical dynamic stability was estimated by using the linear hydrodynamic derivatives, the hydrodynamic derivatives of the submarine, which have a high propriety, were provided by using the fourier analysis of measured forces and moments. Furthermore it is confirmed that the experimental derivatives shows well agreement with the theoretical estimations, and the dynamic stability of the submarine was estimated as a good state, which implies that the value is greater than zero.

• Economic and Environmental Geology
• /
• v.56 no.3
• /
• pp.293-300
• /
• 2023

The Shape Preferred Orientation (SPO) method has been used to analyze the orientation of fault motion, which is utilized as basic data for fault kinematics studies. The rigid grains, which as quartz, feldspar, and rock fragments, in the fault gouge are arranged in the P-shear direction through rigid body rotation by a given shear stress. Using this characteristic, the fault motion can be estimated from the SPO inversely. Recently, a method for securing precision and reliability by measuring 3D-SPO using X-ray CT images and examining the shape of a large number of particles in a short time has been developed. As a result, the SPO method analyzes the orientation of thousands to tens of thousands of particles at high speed, suggests the direction of fault motion, and provides easy accessibility and reliable data. In addition, the shape information and orientation distribution data of particles, which are by-products obtained in the SPO analysis process, are expected to be used as basic data for conducting various studies such as the local deformation of fault rocks and the fault generation mechanism.

• Korean Journal of Remote Sensing
• /
• v.36 no.5_1
• /
• pp.763-774
• /
• 2020

Wind data forecasted from the numerical weather prediction (NWP) model is generally used as the first-guess of the target tracking process to obtain the atmospheric motion vectors(AMVs) because it increases tracking accuracy and reduce computational time. However, there is a contradiction that the NWP model used as the first-guess is used again as the reference in the AMVs verification process. To overcome this problem, model-independent first guesses are required. In this study, we propose the AMVs derivation from Lucas and Kanade optical flow method and then using it as the first guess. To retrieve AMVs, Himawari-8/AHI geostationary satellite level-1B data were used at 00, 06, 12, and 18 UTC from August 19 to September 5, 2015. To evaluate the impact of applying the optical flow method on the AMV derivation, cross-validation has been conducted in three ways as follows. (1) Without the first-guess, (2) NWP (KMA/UM) forecasted wind as the first-guess, and (3) Optical flow method based wind as the first-guess. As the results of verification using ECMWF ERA-Interim reanalysis data, the highest precision (RMSVD: 5.296-5.804 ms^-1) was obtained using optical flow based winds as the first-guess. In addition, the computation speed for AMVs derivation was the slowest without the first-guess test, but the other two had similar performance. Thus, applying the optical flow method in the target tracking process of AMVs algorithm, this study showed that the optical flow method is very effective as a first guess for model-independent AMVs derivation.

• Journal of agricultural medicine and community health
• /
• v.29 no.1
• /
• pp.43-63
• /
• 2004

Objectives: The purpose of this study was to classify the patterns of health behaviors of some rural residents in Korea by sub-grouping them into populations with similar patterns of diet quality, physical activity, alcohol consumption and cigarette smoking, and then to investigate the relationship between these health behavior patterns and health status or health management of them. Methods: The study subjects were 722 rural residents above 20 years old on a typical rural district in Korea, and the data used in this study was from the survey data for health planning of a health center. Study questionnaire for this survey was developed from modifying the questionnaire for 'National Nutrition and Health Study' conducted in 1998. To classify health behavior patterns, cluster analysis was conducted. And to test the association of health behavior patterns with health status or health management, multiple logistic regression analysis were conducted. Results: The results and their implications of this study were as follows: 1. We identified six health behavior typologies : 67.8% of the sample had a good diet quality but showed sedentary activity level(good diet lifestyle) and 10.9% had heavy smoking behavior(smoking lifestyle). Individuals included in fitness lifestyle cluster(6.2%) had high physical activity level and those in drinking life style(2.6%) had had mainly large amount of alcohol. Zero point six percent of sample were included in hedonic lifestyle cluster, who showed poor health behaviors in all. Those included in passive lifestyle(11.9%) had no active health promoting activities but tended to avoid risk taking health behavior such as cigarette smoking and alcohol drinking. 2. As a result of logistic regression analysis, to compare with the individuals in good diet lifestyle, the prevalence of chronic diseases of those in fitness lifestyle showed higher and that of those in smoking lifestyle, drinking lifestyle, hedonic lifestyle, passive lifestyle showed lower than them, retrospectively. 3. Adjusting with general characteristics and health status, to compare with the individuals in good diet lifestyle, the proportion of those who had good health management practices in fitness lifestyle was higher, and the proportion of those who had health check in past 2 years was lower than them, retrospectively. Conclusions: There were some differences in health behavior patterns between rural population and national population, which influenced significantly on health status and health management practice of them. We suggested that the health promotion program for them be developed with considering these points.