• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2007년도 춘계학술대회B
• /
• pp.2747-2752
• /
• 2007

A numerical study has been performed on the flow past a two-staged orifice in a rectangular duct. The flow field including the recirculation region behind the orifice was investigated and the pressure drop was calculated. Water was used as a working fluid and the flow was treated as the turbulent flow, of which the Raynolds number was 6000. The main parameters for the pressure drop and the recirculation region were the orifice's inclined angle against the duct, the interval between two orifices, the shape of the orifice's hole having the same area, and the change of the hole position at the same interval. The variation of the flow field was investigated with each parameter. Consequently, it was found that the most dominant parameter influencing the drop of the pressure was the change of the hole position at the same interval between orifices. Especially when the interval between orifices was narrow and the relative position the holes was changed, its effect to the flow field was shown most drastically as a result of this study. The SIMPLER algorithm with FLUENT code was employed to analyze the flow field.

• 소음진동
• /
• 제8권1호
• /
• pp.49-56
• /
• 1998

Although the fundamental resonance frequency of a Helmholts resonator is mainly determined by the volume of the resonator and the size of the hole, it is also affected by the position of the hole and the shape of the resonator. In this study, the inertial end corrections and the fundamental resonance frequencies of concentric pipe resonators are estimated for various positions of the hole and shapes of the resonator by using the 3-D analysis. For an effective noise reduction in concentric pipe resonators with several holes, an optimal spatial hole-distribution is proposed based on the calculated transmission loss for various hole-distributions and sizes of holes.

• 소성∙가공
• /
• 제19권5호
• /
• pp.320-324
• /
• 2010

Multi-Layer Ceramic Circuit(MLCC) in the face of thousands of fine pitch multi hole is processed. However, the fine pitch multi hole has a size of only a few micrometers. Therefore, in order to curtail the measurement time and reduce error, the image processing measurement method is required. So, we proposed an image processing measurement algorithm which is required to accurately measure the fine pitch multi hole. The proposed algorithm gets image of the fine pitch multi hole, extracts object from the image by morphological process, and extracts the parameters of its position and feature by edge detecting process. In addition, we have used the sub-pixel algorithm to improve accuracy. As a result, the proposed algorithm shows 97% test-retest measurement reliability within 2 ${\mu}m$. We found that the algorithm was wellsuited for measuring the fine pitch multi hole.

• 수산해양기술연구
• /
• 제19권1호
• /
• pp.51-56
• /
• 1983

경계요소법에 의하여 U자형 홈(groove)을 가진 평판이 측면 분포하중을 받을 때 끝부에 위치할 원형 Hole의 최적 위치의 해석을 행하고 동일한 모델(model)에 대하여 실험결과를 비교하여 다음과 같은 결론을 얻게 되었다. 1. 원형 Hole이 U자형 홈(groove)에 가까이 접근하게 됨에 따라 초기의 원형 Hole은 c.-c.선에 수직방향이 그 장축이 되는 타원형으로 변화됨을 알 수 있다. 2. 원형 Hole이 U-groove에 접근함에 따라 Hole 과 Groove 사이의 Neck부는 그 횡단면응력이 인장 및 압축이 동시에 존재하다가 점점 전체가 인장역이 됨을 알 수 있다. 3. 원형 Hole이 Groove에 접근함에 따라 판재경계와 Hole 사이의 목(neck)부분은 계속적인 압축상태를 유지한다. 4. U-groove쪽의 Neck area의 응력분포는 그 최대응력치가 Hole로 접근함에 따라 가속적으로 증가하고 Hole의 찌그러짐(distortion)의 방지를 위한 Hole의 최적중심의 위치는 Neck부의 Hole 측면의 압축응력치가 0이 되지 않는 범위가 한계임을 알 수 있다.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
• /
• pp.287-292
• /
• 1993

We use three sensors such as a vision sensor, a proximity sensor, and a force/torque sensor fused by fuzzy logic in a peg-in-hole task. The vision and proximity sensors are usually used for gross motion control and the information is used here to position the peg around the hole. The force/torque sensor is used for fine motion control and the information is used to insert the peg into the hole precisely. Throughout the task, the information of all the three sensors is fused by a fuzzy logic controller. Some simulation results are also presented for verification.

• 전자공학회논문지A
• /
• 제31A권6호
• /
• pp.134-142
• /
• 1994

A kink due to the lasing of the first transverse mode in laser diodes is investigated using rate equations based on the spatial hole burning model. An analytic expression for the kink power is derived and the result agrees well with experimental results. It is also shown that the position of a kink can be identified in the electrical derivative characteristics as well as in light output vs, current characteristics.

• 한국정밀공학회지
• /
• 제21권1호
• /
• pp.101-108
• /
• 2004

An electro-hydraulic manipulator using hydraulic actuators has many nonlinear elements, and its parameter fluctuations are greater than those of an electrically driven manipulator. So it is relatively difficult to obtain stable control performance. In this report, we applied disturbance estimation and compensation type robust control to all axes in a 3-link electro-hydraulic manipulator. From the results of experiment, it was confirmed that the performance of trajectory tracking and attitude regulating is greatly improved by the disturbance observer, which model is the same for each axis. On the other hand, for the autonomous assembly tasks, it is said that compliance control is one of the most available methods. Therefore we proposed compliance control which is based on the position control by disturbance observer for our manipulator system. To realize more stable contact work, the states in the compliance loop are feedback, where not only displacement but also velocity and acceleration are considered. And we applied this compliance control to Peg-in-Hole insertion task and analyzed mechanical relation between peg and hole. Also we proposed new method of shifting the position of end-effector periodically for the purpose of smooth insertion. As a result of using this method, it is experimentally confirmed that Peg-in-Hole insertion task with a clearance of 0.05［mm］can be achieved.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1993년도 하계학술대회 논문집 A
• /
• pp.410-413
• /
• 1993

Chamferless peg-in-hole process of the cylindrical type parts using force/torque sensor and vision sensor is analyzed and simulated in this paper. Peg-in-hole process is classified to the normal mode (only position error) and tilted mode(position and orientation error). The tilted mode is sub-classified to the small and the big tilted mode according to the relative orientation error. Since the big tilted node happened very rare, most papers dealt with only the normal or the small tilted mode. But the most errors of the peg-in-hole process happened in the big tilted mode. This problem is analyzed and simulated in this paper using the force/torque sensor and vision senor. In the normal mode, fuzzy logic is introduced to combine the data of the force/torque sensor and vision sensor. Also the whole processing algorithms and simulations are presented.

• 한국안전학회지
• /
• 제4권1호
• /
• pp.59-70
• /
• 1989

This paper deals with the experimental study on the flow characteristics in straight flow can type combustor which has been used for high pressure ratio gas turbine combustor. The author has investigated the effects of swirl number and secondary air hole arrays in axial position on the flow characteristics by adopting the tuft method and 5-Hole Pilot Tube. From these experiments, as the swirl number increases, the results obtained is that the area of recirculation zone becomes wide and the position of vortex-core region approaches to the near of fuel nozzle in the model combustor. The most favourable penetration is obtained when secondary air jet is introduced through the air holes distributed in the form of paralled two rows in axial position of model combustor.

• 한국인터넷방송통신학회논문지
• /
• 제23권2호
• /
• pp.21-27
• /
• 2023

본 논문은 골프에서 퍼팅 조준을 도와주는 앱의 개발에 관한 연구이다. 제안된 앱은 그린에서의 홀 컵의 위치와 크기를 측정하여 조준 시 홀 컵과 조준 지점과의 거리를 알려준다. 이를 위하여 인공지능의 객체 인지 기술을 적용하여 개발하였다. 스마트 폰의 카메라로부터 들어오는 이미지에 대하여 객체 인지 기술을 사용하여 실시간으로 홀 컵의 위치와 크기를 측정한다. 그 결과를 이용하여 카메라의 이미지 위에서 조준 지점과 홀 컵과의 거리를 표시함으로써 조준을 도와주는 것이다. 제안된 앱은 아이폰의 iOS에서 개발하였다. 개발된 앱의 성능 측정 결과 실시간으로 충분히 홀 컵을 인지하여 도움 정보를 출력할 수 있었으며, 표시된 거리도 조준에 도움이 될 정도로 정확하였다.