• 로봇학회논문지
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• 제11권3호
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• pp.183-192
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• 2016

Generating motion of center of mass for biped robots is a challenging issue since biped robots can easily lose balance due to limited contact area between foot and ground. In this paper, we propose force control method to generate high-speed motion of the center of mass for horizontal direction without losing balancing condition. Contact consistent multi-body dynamics of the robot is used to calculate force for horizontal direction of the center of mass considering balance. The calculated force is applied for acceleration or deceleration of the center of mass to generate high speed motion. The linear inverted pendulum model is used to estimate motion of the center of mass and the estimated motion is used to select either maximum or minimum force to stop at goal position. The proposed method is verified by experiments using 12-DOF torque controlled human sized legged robot.

• Tribology and Lubricants
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• 제24권6호
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• pp.285-290
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• 2008

The purpose of this paper is to present the case study of tribological failure analysis on the gear damages, oil leakage, and sealant sealing in a manual transmission of front engine and front wheel drive vehicle. The manual transmission is to change the speed range and direction of the engines depending on the driving conditions by friction driving forces with input and output gear system. The material property and surface roughness of the gears are strongly related to the gear noise and micro-vibration, oil leakage and wear, which may decrease the real contact area of the gear and the strength of the oil film thickness between the driving gear and driven one. The O-ring damage of speedometer driven gear and bad sealant sealing of oil pan may produce oil leakage through the contact surfaces, which cause the oil shortage and seizure on the sliding surfaces of the transaxle gears. In the failure case study, the proper repair working and good lubrication are very important for the long life of the transaxle without any tribological failures and oil leakage.

• 한국초전도ㆍ저온공학회논문지
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• 제10권3호
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• pp.1-4
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• 2008

For the effective evaluation of superconducting properties of a coated conductor, with a long length, a non destructive characterization technique including a reel-to-reel (R2R) Hall measuring system have been developed. A non-contact R2R Hall sensor array system was particularly designed to measure the superconducting property of coated conductors. The superconducting properties of long length coated conductors were measured by using this device. It was demonstrated that this system was convenient to measure the intensity and distribution of the magnet field applied perpendicular to the surfaces of the coated conductors. Using this device, the defect and low critical current density(Jc) area of coated conductors could be detected in real-time measurement.

• Journal of Welding and Joining
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• 제14권6호
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• pp.131-139
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• 1996

The response of the arc sensor using the welding current and/or welding voltage as its outputs has been obtained by the analysis and/or experiments of the static characteristics of arc sensor. But in order to improve the reliability of arc sensor, it is necessary to know its dynamic characteristics. So in this paper, it is presented the dynamic model of arc sensor including the power source, arc voltage, electrode burnoff rate, and wire feed rate. A numerical simulation of the dynamic model of arc sensor was implemented, computing the welding current with input of CTWD. The results of computer simulations and experiments of $CO_2$arc welding showed that a linear relationship between weaving center - weld line distance and current area difference was established. Additionally, a real-time weld seam tracking system interfaced with industrial welding robot was constructed, the result of the weld seam tracking experiment for weld line with an initial offset error of 5$^{\circ}$was good.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.433-433
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• 2012

As the requirement in patterning geometry continuously shrinks down, the termination of etch process at the exact time became crucial for the success in nano patterning technology. By virtue of real-time optical emission spectroscopy (OES), etch end point detection (EPD) technique continuously develops; however, it also faced with difficulty in low open ratio etching, typically in self aligned contact (SAC) and one cylinder contact (OCS), because of very small amount of optical emission from by-product gas species in the bulk plasma glow discharge. In developing etching process, one may observe that coupon test is being performed. It consumes costs and time for preparing the patterned sample wafers every test in priority, so the coupon wafer test instead of the whole patterned wafer is beneficial for testing and developing etch process condition. We also can observe that etch open area is varied with the number of coupons on a dummy wafer. However, this can be a misleading in OES study. If the coupon wafer test are monitored using OES, we can conjecture the endpoint by experienced method, but considering by data, the materials for residual area by being etched open area are needed to consider. In this research, we compare and analysis the OES data for coupon wafer test results for monitoring about the conditions that the areas except the patterns on the coupon wafers for real-time process monitoring. In this research, we compared two cases, first one is etching the coupon wafers attached on the carrier wafer that is covered by the photoresist, and other case is etching the coupon wafers on the chuck. For comparing the emission intensity, we chose the four chemical species (SiF2, N2, CO, CN), and for comparing the etched profile, measured by scanning electron microscope (SEM). In addition, we adopted the Dynamic Time Warping (DTW) algorithm for analyzing the chose OES data patterns, and analysis the covariance and coefficient for statistical method. After the result, coupon wafers are over-etched for without carrier wafer groups, while with carrier wafer groups are under-etched. And the CN emission intensity has significant difference compare with OES raw data. Based on these results, it necessary to reasonable analysis of the OES data to adopt the pre-data processing and algorithms, and the result will influence the reliability for relation of coupon wafer test and whole wafer test.

• 전기학회논문지
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• 제58권10호
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• pp.2071-2078
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• 2009

In this paper, we proposed a non-contact respiration measurement system with ultrasonic proximity sensor. Ultrasonic proximity sensor approach of respiration measurement which respiration signatures and rates can be derived in real-time for long-term monitoring is presented. 240 kHz ultrasonic sensor has been applied for the proposed measurement system. The time of flight of sound wave between the transmitted signal and received signal have been used for a respiration measurement from abdominal area. Respiration rates measured with the ultrasonic proximity sensor were compared with those measured with standard techniques on 5 human subjects. Accurate measurement of respiration rate is shown from the 50 cm measurement distance. The data from the method comparison study is used to confirm the performance of the proposed measurement system. The current version of respiratory rate detection system using ultrasonic can successfully measure respiration rate. The proposed measurement method could be used for monitoring unconscious persons from a relatively close range, avoiding the need to apply electrodes or other sensors in the correct position and to wire the subject to the monitor. Monitoring respiration using ultrasonic sensor offers a promising possibility of non-contact measurement of respiration rates. Especially, this technology offers a potentially inexpensive implementation that could extend applications to consumer home-healthcare and mobile-healthcare products. Further advances in the sensor design, system design and signal processing can increase the range of the measurement and quality of the rate-finding for broadening the potential application areas of this technology.

• Steel and Composite Structures
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• 제30권2호
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• pp.109-121
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• 2019

This paper presents the second part of the modeling for the strap combined footings, this part shows a mathematical model for design of strap combined footings subject to axial load and moments in two directions to each column considering the soil real pressure acting on the contact surface of the footing for one and/or two property lines of sides opposite restricted, the pressure is presented in terms of an axial load, moment around the axis "X" and moment around the axis "Y" to each column, and the methodology is developed using the principle that the derived of the moment is the shear force. The first part shows the optimal contact surface for the strap combined footings to obtain the most economical dimensioning on the soil (optimal area). The classic model considers an axial load and a moment around the axis "X" (transverse axis) applied to each column, i.e., the resultant force from the applied loads is located on the axis "Y" (longitudinal axis), and its position must match with the geometric center of the footing, and when the axial load and moments in two directions are presented, the maximum pressure and uniform applied throughout the contact surface of the footing is considered the same. A numerical example is presented to obtain the design of strap combined footings subject to an axial load and moments in two directions applied to each column. The mathematical approach suggested in this paper produces results that have a tangible accuracy for all problems and it can also be used for rectangular and T-shaped combined footings.

• 대한토목학회논문집
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• 제28권3A호
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• pp.357-366
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• 2008

본 연구는 교량 신축이음에 대해서 윤하중 재하실험을 통해 윤하중 재하 특성을 분석하고 이를 토대로 신축이음에서의 윤하중 재하기준을 마련하는 기초데이터를 확보하고자 실시하였다. 이를 위해 국내에서 많이 사용되고 있는 레일신축이음과 핑거신축이음에 대하여 시험체를 제작하고 실제 타이어 바퀴를 사용한 정적 윤하중 재하실험을 실시하였다. 윤하중에 접촉된 레일과 핑거에서 윤하중 분배율을 파악하였는데, 레일신축이음에서 중앙 레일이 지지하는 분담율은 윤하중 크기가 증가함에 따라 감소하는 것으로 나타났고 핑거신축이음에서는 접촉 면적 증가에 따라 거의 증가하지 않고 일정하게 됨을 알 수 있었다. 윤하중 재하 특성이 기존 설계기준과 많은 차이를 나타내고 있으므로 신축이음 설계를 위한 윤하중 접지압력 분포에 대한 합리적인 기준 마련이 필요하다고 판단되었다.

• 한국정밀공학회지
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• 제24권12호
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• pp.104-110
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• 2007

Internal defects are mainly caused by a corrosive action and degradation in the pipe used in a nuclear power plant or factory. The ESPI method have the many advantages when compared with conventional method. The advantage are the area measurement ability at one time and non-contact measurement ability in the real-time. In this paper, we studied on the measurement of a internal defect by using out of plane ESPI technique. Here, we compared the experimental results using out of plane ESPI with the FEM results.

• 한국정밀공학회지
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• 제23권10호
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• pp.74-79
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• 2006

In this study, the tempering effect on the wear characteristics of induction-hardened SPS5 steel was investigated. For this purpose, three tempering conditions were applied to control the hardness of heat-treated SPS5 steel. Ball-on-disk wear tests have been performed using zircornia balls on the tempered specimens to determine the variation of wear characteristics. The results showed that friction coefficient decreased with increasing hardness for induction hardening conditions. This seems to occur because real contact area between specimen and mating ball was affected by the specimen hardness.