• International Journal of Precision Engineering and Manufacturing
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• 제4권3호
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• pp.12-19
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• 2003

This paper describes the design of a robot's hand with two fingers for stably grasping an unknown object, and the development of a 3-axis force sensor for which is necessary to constructing the robot's fingers. In order to safely grasp an unknown object using the robot's fingers, they should measure the forces in the gripping and in the gravity directions, and control the measured forces. The 3-axis force sensor should be used for accurately measuring the weight of an unknown object in the gravity direction. Thus, in this paper, the robot's hand with two fingers for stably grasping an unknown object is designed, and the 3-axis force sensor is newly modeled and fabricated using several parallel-plate beams.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 추계학술대회 논문집
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• pp.85-89
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• 2002

This paper used the Laser Speckle Interferometry to present the strain analysis of Nd:YAG Laser welding zone. Previous TIG welding to sheet plate, which welds only high-skilled engineer, produces residual stress nearby welding zone due to thermal effect. However, Laser welding makes sheet pate welding easy and thermal effect minimum. Thermal effect zone is measured by strain analysis of the laser-welding zone by ESPI under tensile testing of sheet plate welded by Nd:YAG laser. The ESPI results, which compared with strain gage method, are agreed within error 3 %.

• 대한기계학회논문집A
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• 제26권9호
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• pp.1874-1881
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• 2002

Heat dissipation technology using the flow resonant phenomenon is a kind of a new concept in the heat transfer area. A vibration exciter is needed to enhance air flow mixing which has the natural shedding frequency of thermal system. A mechanical vibrating device for the air flow oscillation is introduced, which is driven by a moving coil actuator with a displacement estimator using strain gage. An analytical dynamic model for this mechanical vibration exciter is presented and its validity is checked by the comparison with experimental data. Values of some unknown system parameters in the analytic model are estimated through the system identification approach. Based on this mathematical model, the vibration exciter using strain displacement estimator is developed. During the experimental verification phase, it turns out the high modal resonant characteristics of a vibrating plate are a major barrier against obtaining a high bandwidth vibration exciter.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 C
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• pp.1416-1418
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• 1994

Expressions for the displacement of a bimorph, one end fixed and the other free, has been introduced when sinusoidal inputs were applied to the ceramic plates on a thin metal plate. Maximum displacements at the free end and strains at the position of strain gage attached were measured when various wave forms, voltages, and frequencies were applied to the bimorph whose length is 6.6[cm], width 2.5[cm], and thickness 0.0365[cm]. Under the constant voltage ( $70[V_{peak}]$ ), the strains and the displacements at the free end were larger than the case of the sinusoidal input when the square wave was applied and were smaller when triangular wave. It was shown that the displacements at the free end and the strains of the gage position were increased as the applied voltage in the range of $30-90[V_{peak}]$ and effective length were increased. And it was also found that the resonant frequency of a bimorph was decreased as its effective length was increased, and that the displacements and the strains were maximum at the resonant frequency.

• 대한기계학회논문집A
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• 제22권2호
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• pp.353-364
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• 1998

This paper describes the design processes and evaluation results of a small-sized six-axis force/torque sensor. The new six-axis force/torque sensor including S-type structure has been developed using a parallel plate structure as a basic sensing element. In order tominimize coupling errors, the location of strain gages has been determined based on the finite element analysis and the connections of strain gages have been made such that the bridge circuit with 4 strain gages becomes balanced. Several design modifications result in a similar strain sensitivity for six-axis forces and moments, and the reduced coupling errors of 2.6% FS between each forces and moments. Calibration test results show that the six-axis load cell developed which has light weight of 135g and the maximum capacities of 196 N in forces and 19.6 N.m in moments is estimated to be within 7.1% FS in coupling error.

• 한국강구조학회 논문집
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• 제25권5호
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• pp.543-553
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• 2013

춤이 깊은 골형 데크는 그 단면의 형태가 개방형 단면(개단면(開斷面))으로 단면의 불안정성에 의한 휨비틀림 등의 구조적 문제를 일으킬 수 있다. 박판의 냉간성형강인 데크와 캡플레이트의 접합에 사용되는 연결재(파스너)는 볼트, 리벳, 용접 그리고 나사 접합이 있다. 이 연구는 냉간성형강을 사용한 춤이 깊은 데크와 보강용 캡플레이트간의 직결나사 접합부에 관한 실험적 연구로, 직결나사 접합부의 파괴거동과 최대내력에 영향을 주는 직결나사 배치방법, 직결나사 수, 직결나사 간격 그리고 직결나사 머리밑판의 두께변화를 실험변수로 하여 국외 설계기준식 비교 분석하고자 한다.

• 한국운동역학회지
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• 제13권3호
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• pp.341-354
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• 2003

The purpose of this study was to develop the uniaxial force plate system which is measured by the vertical force. The VGRF(vertical ground reaction force) 1.0 was composed of 2 bath digital scales, 2 indicaters, and analyzing software. This system was newly renovated to VGRF 2,0 which are 2 industrial digital scales, 2 adjustable indicators, and enforced analyzing software. Changes of the new system were as follows. First, the height of the plate was 75% lower than before. Second, sensing ability of the load cell was changed from 90 - 0.05kg to 300 - 0.1kg. Third, the speed of data processing was changed from 17 per second to 60 per second. Fourth, analyzing software was enforced to develop and calculate the data. For the test of the system, two different types(bare foot, high-heeled shoes) gait was adopted. highly skilled female walker(23yrs, height 165cm, body mass 46.8kg) participated for the experimental study. During the dynamic performance(gait analysis), the data of each load cell were very similar to the previous studies. Specifically, bare foot walking had less vertical force than high-heeled shoes. Consequently, VGRF 2.0 can sense the general dynamic movements as well as static load conditions.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.60-65
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• 2007

Local buckling behaviors of aluminum square tube beams reinforced by aluminum plates under three point bending loads have been analyzed using experimental tests combined with theoretical and finite element analyses. For this analysis true stresses were determined from applied loads and cross-sectional area records of a tensile specimen with a rectangular cross-section by real-time photographing. True strains were also obtained from in-situ local elongation measurements of the specimen gage portion by the multi-point scanning laser extensometer. Six kinds of aluminum tube beam specimens reinforced by aluminum plates were employed for the bending test. The bending deformation behaviors up to the maximum load analyzed by the numerical simulation agreed well with experimental ones. After passing the maximum load, reinforcing plate hindering the local buckling of the tube beam was debonded from the aluminum tube beam. An aluminum tube beam strengthened by aluminum plate on the upper web showed the most excellent bending capacity, which could be explained on the basis of the neutral axis shift and the local buckling deformation range.

• 한국자동차공학회논문집
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• 제13권5호
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• pp.171-180
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• 2005

Bending performances of aluminum square tube beams reinforced by aluminum plates under three point bending loads have been evaluated using experimental tests combined with theoretical and finite element analyses. A finite element simulation for the three-point bending test was performed. Basic properties of aluminum materials used for initial input data of the finite element simulation were obtained from the true stress-true strain curves of specimens which had been extracted from the Al tube beams. True stresses were determined from applied loads and cross-sectional area records of a tensile specimen with a rectangular cross-section by real-time photographing, and true strains were obtained from in-situ local elongation measurements of the specimen gage portion by the multi-point scanning laser extensometer. Six kinds of aluminum tube beam specimens adhered by aluminum plates were employed fur the bending test. The bending deformation behaviors up to the maximum load described by the numerical simulation were in good agreement with experimental ones. After passing the maximum load, reinforcing plate was debonded from the aluminum tube beam. An aluminum tube beam strengthened by aluminum plate on the upper web showed an excellent bending capability.

• 한국강구조학회 논문집
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• 제21권5호
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• pp.527-536
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• 2009

본 연구의 목적은 박판 탄소강 일면전단 2행 2열 볼트접합부의 블록전단파단거동과 면외변형의 영향을 조사하는 것이다. 하중직각 방향 연단거리, 볼트직경, 피치, 게이지 치수를 고정하고 블록전단파단이 발생하도록 실험체를 계획한다. 접합평판의 두께, 하중방향연단거리를 주요변수로 설정한다. 단순인장 실험을 실시하고 블록전단파단 양상, 최대내력을 현행의 설계기준식에 의한 예측치와 비교한다. 또한, 판 두께와 연단거리에 따른 하중방향과 직각방향으로 발생하는 면외변형의 발생조건을 조사하고 면외변형의 발생으로 인한 내력저하정도를 고찰한다.