피스톤의 형상 모델링 및 CNC 가공 데이터 산출용 소프트웨어 개발

이철수,이제필,김성복,Lee, Cheol-Soo,Lee, Je-Phil,Kim, Seong-Bok 대한산업공학회 1999 산업공학 Vol.12 No.1

A noncircular cutting such as a piston cutting has depended on the copy-machining because of its complex shape. But the copy-machining needs a master model and brings about a low quality of the piston caused by being worn out of the master model. And the lower cutting speed reduces the productivity. In this paper, for solving these problems, a specialized software system and its subsequent procedure are presented. The shape of a piston consists of an oval, an offset, recesses, and eccentricities. The paper describes these shapes as a consistent equation that is a function of the rotational angle and the position of longitudinal direction(Z-axis). It is simple to define the characteristic geometry of a piston and to generate a tool path for CNC machining. This paper proposes the a proper structure of a 4-axes CNC(Computerized Numerical Control) lathe for machining the piston. As well as X-axis and Z-axis, are attached to the machine a C-axis for rotation and a Y-axis for higher speedy prismatic motion parallel to X-axis.

상호 결합을 이용한 광대역 E-면 H 섹터 혼 위상 배열 안테나 설계

이철수,백정기,Lee, Cheol-Soo,Pack, Jeong-Ki 한국전자파학회 2007 한국전자파학회논문지 Vol.18 No.6

H 섹터 혼 안테나는 일정한 빔 커버리지를 가지면서 빔 조향을 하는 광대역 위상 배열 송신기의 복사 소자로 유용하다. 본 논문에서는 상호 결합을 이용하여 3:1 주파수 대역과 ${\pm}60^{\circ}$의 빔 조향 범위를 갖는 광대역 E-면 H 섹터 혼 위상 배열 안테나를 설계하였다. 주자계면에서 반전력 빔 폭이 $30{\sim}50^{\circ}$을 갖는 H 섹터 혼 안테나를 설계하였다. 도파관 시뮬레이터를 이용하여 상호 결합을 포함하는 능동 반사 계수를 계산하였고, 광대역 주파수 범위에서 상호 결합에 의하여 능동 반사 특성이 개선되었다. 이러한 결과를 이용하여 $8{\times}1$ H 섹터 혼 위상 배열안테나를 제작하였다. 주자계면에서의 반전력 빔 폭과 능동 반사 계수의 측정 결과는 시뮬레이션 결과와 잘 일치하였다. 빔 조향된 복사 빔들의 첨두치 패턴은 능동 소자 패턴과 잘 일치하였다. 3:1 주파수 대역과 빔 조향 범위에서 능동 반사 계수는 대부분 0.3 이하로 측정되었다. An H-sector horn antenna has a constant beam coverage characteristic and it can be useful for application to a wide band phased array antenna system. In this paper, we designed a broadband E-plane H-sector horn phased-array antenna, which has a 3:1 bandwidth and ${\pm}60^{\circ}$ beam steering capability. An H-sector hem antenna was designed to have $30{\sim}50^{\circ}$ half-power beam width in the principal H-plane. The active reflection coefficient including mutual coupling was calculated using a waveguide simulator, and the active reflection characteristic was improved by mutual coupling over wide frequency range. Using these results, an $8{\times}1$ H-sector phased array antenna was fabricated. The measurement results for the half-power beam width in the principal H-plane and the active reflection coefficient showed a good agreement with the simulation results. The peak-value pattern in the steered radiation beams also agreed well with the active element pattern. The measured active reflection coefficients within the beam steering range are mostly less than 0.3 over the 3:1 frequency range.

자동차 타이어 모델의 곡면 모델링 및 5축 NC 가공

이철수,Lee, Cheol-Soo 대한산업공학회 1996 산업공학 Vol.9 No.2

Recently, the tire mold of a passenger car is made almost via aluminum casting, and it is necessary to prepare a master model of the tire for the casting. Because of the geometrical feature of tire, as well known, the master model must be machined by a 5-axis NC machine. The paper proposes a procedure to model and machine the master model. The approach includes (a) transformation of 2D drawing of tire into 3D geometry, (b) modeling surfaces of tire, and (c) inverse kinematics of a 5-axis NC machine. An implementation of the proposed procedure is also presented.

타이어 사이드판의 문자 가공을 위한 4축 가공 시스템

이철수,박광렬,Lee, Cheol-Soo,Park, Gwang-Ryeol 대한산업공학회 1998 산업공학 Vol.11 No.2

The letters of the automobile tire are usually engraved on the side-wall. The shape of the side-wall is a sculptured surface generated by the rotational sweeping of a profile curve. The letters laid on the side-wall are usually designed by a 2-dimensional CAD. It is impossible to machine the letters on the surface accurately by 3-axis NC machining, because the axis of cutter should be tilted to align with the normal vector of the surface. In this case. the degree of freedom for the machine is at least four. This paper describes an idea for tool path generation of a 4-axis machine by using the 2-dimensional CAD data of the letters and the surface of the side-wall. This study includes the following procedures; (1) measuring the profile of the side-wall surface and curve-fitting of the measured points. (2) the 'non-parallel projection' of the letters on the side-wall, and (3) an inverse kinematics of the 4-axis lettering machine. Procedures in this paper are programmed in C-language on Windows95 environment. With a PC based CNC controller and a 4-axis lettering machine. these are tested sucessfully for the practical use.

선박용 플랫바의 자동 네스팅 및 가스/플라즈마에 의한 NC 절단

이철수,박광렬,Lee, Cheol-Soo,Park, Gwang-R. 대한산업공학회 1996 산업공학 Vol.9 No.3

The 'flat-bar' is a stiffener which is a component of ships. It is basically a long rectangle and has 'end-cut' shapes at both sides. The paper describes a fast nesting algorithm of the flat-bar, and a procedure to generate cutting path of gas/plasma torch, which is operated by a NC (numerically controlled) gas/plasma cutting machine. Proposed procedures are written in C-language and executable on VAX machine with Open VMS operating system.

컴퓨터 비젼에 의한 PCB 검사를 위한 검사 정보 생성 시스템 개발

이철수,고은희,Lee, Cheol-Soo,Go, Eun-Hee 대한산업공학회 1998 산업공학 Vol.11 No.2

For the PCB inspection by computer vision, in some cases, the MRLC file should prepared. The MRLC file contains a RLC(Run Length Code) and a direction flag. In this paper, a generating method of MRLC is described. It is composed of two procedure as followings; (i) rasterizing Gerber file which is a vectorized image of PCB panel, and (ii) calculating a MRLC that is useful for the inspection as a template image. The suggested procedures are written in C-language and executable on Windows 95 and Windows NT.

다중 증폭 회로를 이용한 높은 선형 특성을 갖는 광대역 능동 안테나 설계

이철수(Cheol-Soo Lee),정근석(Geoun-Seok Jung),백정기(Jeong-Ki Pack) 한국전자파학회 2008 한국전자파학회논문지 Vol.19 No.11

능동 안테나는 수동 안테나에 비하여 소형으로 광대역 특성 및 높은 이득을 얻을 수 있으나, 잡음 및 불요파 신호가 발생되는 단점이 있다. 또한, 수신 시스템의 초단부에 위치하므로, 고감도 수신 시스템을 위하여 불요파 신호 특성이 좋아야 한다. 본 연구에서는 출력단 P1dB가 3 ㏈m 이상이고 100~500 ㎒에서 동작하며, 실환경에서 높은 선형 특성을 갖는 능동 안테나를 개발하였다. 이를 위하여 공통 드레인 FET와 2단 BJT의 능동 회로를 구성하였고, ADS를 이용하여 능동 안테나를 설계하였다. 제작된 능동 안테나의 평균 이득, 평균 잡음 지수, OIP3, VSWR 및 P1dB는 각각 9.7 ㏈i, 10 ㏈, 14 ㏈m, 1.7:1 및 3 dBm으로 설계치와 잘 일치하였다. 도심 인근지역에서 측정된 수신 스펙트럼 특성은 설계된 능동 안테나가 CS 구조를 갖는 참고문헌 [9]의 안테나보다 불요파 신호 특성이 약 10~30 ㏈B가 개선되어 방송 및 상용 신호와 혼재된 상태에서 신호 세기가 약한 미지의 신호를 검출하기 위한 고감도 수신 시스템에 적용할 수 있음을 보였다. An active antenna(AA) can have wider bandwidth and more gain with small antenna size than those of passive antennas. However, AA inherently generates thermal noise and spurious signals from an active device. Moreover, the spurious performance of AA is very important in a highly sensitive receiving system since it is located at the front end of the receiving system. In this study, we developed an AA with 100~500 ㎒, having the output P1dB higher than 3 ㏈m and little spurious signals in real environments. To achieve such performance, we designed an AA with 3-stage amplifier using CD(common drain) FET and 2 BJTs. Its electrical performances were simulated using ADS. The measurement results for typical gain, NF, OIP3, VSWR and P1dB in the required frequency band were 9.7 ㏈i, 10 ㏈, 14 ㏈m, 1.7:1 and 3 ㏈m respectively. They are in good agreement with simulation results. The unwanted spectrum level of the proposed AA is 10~30 ㏈ lower than that of the antenna<SUP>[9]</SUP> with CS(common source) FET configuration at a west suburban area of Seoul, which shows that the proposed AA can be applicable to a highly sensitive receiving system for detecting unknown weak signals mixed with broadcasting and civilian communication signals.

등가 모델을 이용한 광대역 수신용 능동 다이폴 안테나 설계

이철수(Cheol-Soo Lee),백정기(Jeong-Ki Pack) 한국전자파학회 2008 한국전자파학회논문지 Vol.19 No.1

VHF 대역에서 능동 안테나는 작은 크기로 인하여 많이 사용되고 있다. 능동 안테나는 안테나와 증폭기가 직접 연결되어 있으며, 수신 시스템의 초단부에 위치하고 있으므로, 능동 안테나의 이득 및 잡음 지수 특성은 좋은 감도를 위하여 중요하다. 본 연구에서는 5:1 대역폭(100~500 ㎒)에서 동작하며, 다이폴과 P-HEMT 증폭기로 구성되는 능동 다이폴 안테나를 개발하였다. 능동 다이폴 안테나의 요구된 성능을 얻기 위하여, 안테나와 증폭기를 동시에 설계되어야 한다. 이를 위하여, 1-포트 다이폴 안테나를 등가의 2-포트 시스템으로 모델링하는 등가 포트 개념을 도입하였다. 이러한 제안된 등가 포트를 이용하여 ADS로 능동 다이폴 안테나의 성능에 대한 시뮬레이션 하였다. 안테나의 이득과 잡음 지수 특성을 측정하기 위하여, 2-포트 등가 임피던스 모델을 이용하였다. 제작된 능동 다이폴 안테나의 측정된 평균 이득, 잡음 지수 및 VSWR은 각각 8 ㏈i, 9 ㏈, 1.7:1이다. 방사 패턴은 다이폴 안테나와 같은 특성을 얻었다. 시뮬레이션 결과와 측정된 결과를 비교 시, 제안된 방법의 타당성을 확인하였다. In the VHF range, active antennas are widely used for wideband applications due to their small size. Active antenna consists of antenna elements and amplifiers, which are directly connected to each other. Gain and noise-figure characteristics are very important for good sensitivity performance, because it is located at the front end of a receiving system. In this study, we developed an active dipole antenna with 5:1 bandwidth(100~500 ㎒), which consists of a dipole antenna and a P-HEMT amplifier. To obtain required performances, the antenna and the amplifier should be designed simultaneously. In order for that, we introduced an equivalent port concept to model the 1-port dipole antenna as an equivalent 2-port system. Using the proposed equivalent port, the performance of the active dipole antenna was simulated by the ADS. In order to measure the gain and noise-figure characteristics of the antenna, we utilized the same concept of the two-port equivalent impedance model. The measurement results for typical gain, NF and VSWR in the required frequency band were 8 ㏈i, 9 ㏈ and 1.7:1, respectively. The radiation patterns at the principal planes were same as the typical radiation pattern of a dipole antenna. By comparing the simulation results with measured ones, it is confirmed that the proposed methods works well.

조선 블록 운반용 Lug 배치 자동화 시스템

이철수(Cheol Soo Lee),이재현(Jae Hyun Lee),심주현(Ju Hyun Shim),허은영(Eun Young Heo),김종민(Jong Min Kim) (사)한국CDE학회 2012 한국 CAD/CAM 학회 학술발표회 논문집 Vol.2012 No.2

스크랩 형상을 고려한 효율적 네스팅

이철수(Cheol Soo Lee),허은영(Eun Young Heo),김종민(Jong Min Kim),김동수(Dong Soo Kim) (사)한국CDE학회 2011 한국 CAD/CAM 학회 학술발표회 논문집 Vol.2011 No.1

The automatic nesting acting as a CAM system in shipbuilding industry has more constrains any other field nesting such as automobile, clothes and shoes. The nesting software has a big influence on the productivity of shipbuilding industry while it is equipped with useful functions: automated operation system, user friendly interface, generation of stable cutting data and draft, synchronization with ERP system. Many algorithms have been developed to decrease the scrap ratio and to increase the utilization of metal sheet plate. However, the satisfaction respecting to the minimization of computational time and scrap is not fulfilled yet. This study presents the attractive nesting algorithm to identify the scrap by defining the attributes while the ship parts are arranged by two steps. The bitmap-based arrangement squeezes the part to left-bottom side of plate. Secondly, the rearrangement step is carried out to more decreasing the scrap while an overlap between parts is allowed and released by moving the previously placed parts. To increase the computational efficiency in the second step, the attributes of scrap are used. The proposed method is validated using actual ship parts.