• 한국정밀공학회지
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• 제18권7호
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• pp.40-45
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• 2001

This paper proposes a methodology for the small-displacement-movement of a piston and develops a hybrid control algorithm for the precision position control of a pneumatic rodless cylinder. The pneumatic system uses the voltage-proportional solenoid valves to minimum valve switching since the on/off type valves are create diffculties for accurate position control and induce a lot of valve switching. For the accurate position control a methodology for the small-displacement-movement of the piston is developed and identified experimentally. The main consideration on the development of the hybrid control law is to eliminate a stick-slip phenomenon in the pneumatic control system. This paper addresses these critical issues and presents experimental results for the pneumatic control system.

• 전기학회논문지
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• 제60권10호
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• pp.1959-1965
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• 2011

Measuring the movement of joint angle of human body is very important clinically. Human joint angle displacement can be used to evaluate the degree of disease and disability. Also, we can determine the rehabilitation process with angular information. Conventional methods for measuring angular displacement are many weakness. The purpose of this study is to overcome the limitations of existing equipments by using optical method. For this reason, optical sensor system was used to correlate detected light signal with joint angle. Experimental results of the applied joint model in this study showed that joint angular displacement can be measured by optical signals. The suggested method is simple, durable, small, lightweight, convenient, and cost effective.

• 한국정밀공학회지
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• 제25권1호
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• pp.79-84
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• 2008

For the precision measurement of industrial products, the location of holes inside the products, if they exist, are often selected as feature points. The measurement of hole location would be performed by vision and laser-vision sensor. However, the usage of those sensors is limited in case of big change of light intensity and reflective shiny surface of the products. In order to overcome the difficulties, we have developed a hole displacement measuring device using contact-type displacement sensors (LVDTs). The developed measurement device attached to a robot measures small displacement of a hole by allowing its X-Y movement due to the contact forces between the hole and its own circular cone. The developed device consists of three plates which are connected in series for its own function. The first plate is used for the attachment to an industrial robot with ball-bush joints and springs. The second and third plates allow X-Y direction as LM guides. The bottom of the third plate is designed that various circular cones can be easily attached according to the shape of the hole. The developed system was implemented for its effectiveness that its measurement accuracy is less than 0.05mm.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.360-363
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• 2005

Biomimetic actuators composed of cellophane with an electrically conducting polyaniline(PANI) film have been fabricated and tested in air ambience conditions doped with two different counter ions such as perchlorate (${ClO_4}^-$) and tetrafluoroborate (${BF_4}^-$). Fabrication of the trilayer CP//CELLOPHANE//CP substantially enhanced the tip displacement (13.2mm) compared to the small displacement (8.3mm) of the bilaye. CP//CELLOPHANE. The ion migration among layers is the main factor behind the expansion of cellophane, while the expansion/contraction of PANI are dependent on the redox reaction of the polymer. The displacement of the composite is dominated by the humidity content. This implies that the actuation principle is possibly due to the assistance of water existing.

• 한국지반환경공학회 논문집
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• 제23권9호
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• pp.25-31
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• 2022

Attaching shelf to retaining structure leads to a decrease in the total lateral earth pressure. This decrease enables the retaining structures to become more stable, to have small displacement, and to exhibit lower bending moments, the relief shelves effects are analyzed using FEM in order to understand how they stabilize cantilever wall in this study. Several models are varied by changing location and width of shelves to realize earth pressure and displacements of retaining wall. The displacement is getting smaller because earth pressure acting on shelf increases as shelves locations are lower and width is longer. The ground settlement variation effects caused by relief shelves are studied also. The ground settlement increases abruptly where shelf location is between of 0.5H and 0.625H, and settlement decreases suddenly where shelf width is between b/h=0.375 and b/h=0.500. The shelf significantly reduces earth pressure and movement of the wall. This decrease in the lateral pressure increases the retaining structure stability.

• 대한치과교정학회지
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• 제28권4호
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• pp.563-580
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• 1998

치열의 치군 후방이동을 유발하는 교정력에 의해 발생되는 개개 치아의 초기 변위와 응력분포를 평가하고자 본 연구를 시행하였다. 유한요소법을 이용하여 상악 치아와 치근막, 그리고 치조골의 해부학적 형태와 생체적 특성을 컴퓨터로 재현하고 모형화된 브라켓을 부착한 3 차원 유한요소 모델을 형성하였다. 치열의 치군 후방이동에 사용되는 구외력과 II급 악간고무, ideal arch wire와 MEAW(Multiloop Edgewise Arch Wire), 그리고 호선에 부여된 tip back bend 에 의해 야기되는 치아 변위를 비교, 분석하였다 그리고 이러한 치료방법을 상악 제 2 대구치를 발거한 경우와 발거하지 않은 경우에 각각 적용하여 상악 제 2대구치 존재유무에 따른 치아이동 양상의 변화를 분석한 결과 다음과 같은 결론을 얻었다. 1. 전치부 헤드기어에 의해 발생되는 치아변위는 후방 치체변위와 후방 경사변위, 그리고 수직변위 모두 치열 전방부에 집중되어 있었다. 2. Ideal arch wire에 II급 악간고무를 적용한 경우, 치아변위가 치열 전방부에 집중되었으나 ideal arch wire에 tip back bend를 부여하면 악간고무에 의한 견인력이 후방으로 전달되었다. 부여하는 tip back bend의 양이 증가할수록 전치부의 후방 치체변위와 설측 경사변위는 감소하였고 구치부의 후방 치체변위와 경사변위는 증가하였으며 II급 악간고무에 의한 전치부 정출이 감소하였다. 3. MEAW와 II급 악간고무를 적용한 결과, 치아변위 경향은 ideal arch wire와 II급 악간고무를 사용한 경우와 유사하였으나 작은 양의 치아변위와 함께 치열내 개개치아의 비교적 균등한 이동양상을 보였다. 4. 상악 제 2 대구치가 존재하는 유한요소 모델에 상악 제 1 대구치까지만 교정장치를 장착하고 후방이동을 시도한 결과 상악 제 1 대구치 치아이동이 감소하는 경향을 보였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.304-307
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• 2003

In this paper, stacked piezoelectric ceramics were used for obtaining a large vibration for a small ultrasonic motor which is useable for the both linear drive and rotational drive. We studied this motor through the finite element analysis method and the simulated driving characteristics were presented. As results, the displacement of the tip of the stator was increased when the layers of the ceramics were increased. Also, by inserting additional aluminum plates between the ceramics and the aluminum bar, the displacement were amplified. In this model, two voltages which have 90 degree phase difference were applied for the bi-directional movement.

• Structural Engineering and Mechanics
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• 제48권3호
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• pp.367-382
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• 2013

Different types of long slender pile shall buckle with weak soil and liquefied stratum surrounded. Different from considering single side earth pressure, it was suggested that the lateral earth pressure can be divided into two categories while buckling: the earth pressure that prevent and promotes the lateral movement. Active and passive earth pressure calculation model was proposed supposing earth pressure changed linearly with displacement considering overlying load, shaft resistance, earth pressure at both sides of the pile. Critical buckling load calculation method was proposed based on the principle of minimum potential energy quoting the earth pressure calculation model. The calculation result was contrasted with the field test result of small diameter TC pile (Plastic Tube Cast-in-place pile). The fix form could be fixed-hinged in the actual calculation assuring the accuracy and certain safety factor. The contributions of pile fix form depend on the pile length for the same geological conditions. There exists critical friction value in specific geological conditions that the side friction has larger impact on the critical buckling load while it is less than the value and has less impact with larger value. The buckling load was not simply changed linearly with friction. The buckling load decreases with increased limit active displacement and the load tend to be constant with larger active displacement value; the critical buckling load will be the same for different fix form for the small values.

• 자원환경지질
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• 제26권2호
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• pp.227-237
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• 1993

Lineaments in the Kyungsang basin most intensely develop in the East coast domain including the Yangsan fault, which dominantly run in NNE direction. The geometry of small fault population near or along the Yangsan fault represents the dominant strikes of N35E, high angle dips and shallowly plunging rakes with dextral movement sense. Stereographic solution on the Yangsan fault geometry gives the dip of 88SE, the slip direction of 17,024 and the slip rake of 18, which were determined from the strike (N23E) of the fault measured on map, and the average attitude (N35E, 84SE) and fault striation (16, 037) of small fault population considered as Riedel shears. It is judged from the geometry of small fault population to the main Yangsan fault and dragging features of bedding attitude near the fault that the Yangsan fault was produced from dextrally strike-slip movement. The movement of the Yangsan and the adjacent parallel faults is thought to be taken place much later than the other fault sets in the Kyungsang basin. It might occur during the geologic age from Eocence to early Miocene according to the consideration of K-Ar ages of the igneous rocks near the fault. The estimated paleostress state indicates ENE shortening and NNW extension. The displacement of the Yangsan fault in the study area is not constant along the fault but decreases from the south to the north. Taking the northern end of the study area as a separating point the whole extension of the Yangsan fault may be divided into southern and northern segments.

• Smart Structures and Systems
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• 제15권6호
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• pp.1543-1567
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• 2015

In this study, a wireless crack sensor is developed for monitoring cracks propagating in two dimensions. This sensor is developed by incorporating a laser-based optical navigation sensor board (ADNS-9500) into a smart wireless platform (Imote2). To measure crack propagation, the Imote2 sends a signal to the ADNS-9500 to collect a sequence of images reflected from the concrete surface. These acquired images can be processed in the ADNS-9500 directly (the navigation mode) or sent to Imote2 for processing (the frame capture mode). The computed crack displacement can then be transmitted wirelessly to a base station. The design and the construction of this sensor are reported herein followed by some calibration tests on one prototype sensor. Test results show that the sensor can provide sub-millimeter accuracy under sinusoidal and step movement. Also, the two modes of operation offer complementary performance as the navigation mode is more accurate in tracking large amplitude and fast crack movement while the frame capture mode is more accurate for small and slow crack movement. These results illustrate the feasibility of developing such a crack sensor as well as point out directions of further research before its actual implementation.