렌즈왜곡효과를 보상하는 새로운 hand-eye 보정기법 ( A New Hand-eye Calibration Technique to Compensate for the Lens Distortion Effect )

정회범 대한기계학회 2000 대한기계학회 춘추학술대회 Vol.- No.-

입력-제한 시스템을 위한 자기동조 제어 알고리즘의 개발

정회범 순천대학교 공업기술연구소 1991 工業技術硏究所論文集 Vol.5 No.-

Self-tuning control algorithm for an input-constrained systems is developed and implemented in this study. Magnitude of control input for small motors is generally restricted to low level due to actuator saturation. The bounded-gain control algorithm proposed in this study yields smoother control input within the magnitude constraints comparing with the existing Clarke's suboptimal control algorithm. In the proposed algorithm, the system output responds fast at the expense of smoothness of input variation, as the weighting factor is increased. For the DC servo motor control, the system performance of the proposed algorithm is compared with that of the existing algorithm by computer simulation and experiment. The control programs are written in 8086 & 8087 assembly languages for real-time control. The output responses of both algorithms are similar, but smoothness of input variation using the proposed algorithm is verified.

제어입력 크기가 제한되는 자기동조 제어 알고리즘의 구현에 관한 연구

정회범,장효환 대한기계학회 1990 대한기계학회 춘추학술대회 Vol.- No.-

소형 로봇의 연속경로 추종제어

정회범 順天大學校 1994 論文集 Vol.13 No.1

□Magnitude of control inputs for small motors used in robot is generally restricted to low level due to actuator saturation. This paper compares the tracking performance of the bounded-gain adaptive control algorithm with the existing PD control algorithm by computer simulation and experiment. The reference trajectories are obtained using the kinematic model of Rhino XR-2 robot. The robot controller is designed and fabricated for the implementation of the control algorithms. It is shown that the bounded- gain adaptive control algorithm yields better tracking performance and smoother input variation than the PD control algorithm in the two-axis robot control.

탄산가스 아크용접에서 보호가스량에 따른 용접부의 기계적 성질

정회범,김봉태 順天大學校 1998 論文集 Vol.17 No.1

The mechanical properties of a welding part have been examined by varying the shield gas flow rate from 0ℓ/min to 24ℓ/min when the CO₂ gas arc welding with solid wire is used for welding the SS41 steel. The welding parts have been investigated through X-ray film test, bending test and tensile test, which have shown following results ; 1) X-ray film tests show no pores for the shield gas flow rate from 6ℓ/min to 24ℓ/min. But some pores are existed at inner welding part for the flow rate 2ℓ/min and 4ℓ/min. When no gas is supplied, many pores are observed at the inner and the outer welding parts. 2) A bead configuration including a fusion depth and a bead's width and height is good for the shield gas flow rate more than 8ℓ/min. 3) Bending tests show that no cracks were developed for the shield gas flow rate 16ℓ/min to 24ℓ/min. But cracks are developed at the surface of a face side for the flow rate 4ℓ/min to 12ℓ/min. For the flow rate 0ℓ/min and 2ℓ/min, specimens break into pieces. 4) Tensile strength of the welding part increases as the shield gas flow rate increases. The tensile strength of the welding part is much higher than that of the base metal for the flow rate 4ℓ/min to 24ℓ/min. Considering the above results, the effective shield gas flow rate in the CO₂ gas arc welding is 16ℓ/min to 24ℓ/min.

고정카메라와 이동카메라시스템에서 좌표변환의 연관성에 관한 연구

정회범 ( Hoi-bum Chung ) 한국환경기술학회 2007 한국환경기술학회지 Vol.8 No.3

시각서보시스템은 위치기반 시각서보와 영상기반 시각서보로 구분할 수 있는데 두 기법은 각각의 장점과 단점을 가진다. 최근들어 Malis 등이 2.5D 시각서보를 개발하였는데 이 기법은 호모그라피를 통해 병진운동과 회전운동사이의 연관관계를 분해할 수 있는 사실을 이용한다. 호모그라피는 시각서보에 사용되는 Euclidean 재생성을 제공하지만 그 물리적 의미는 명확하지 않다. 본 연구에서는 가상좌표계를 사용하여 고정카메라와 이동카메라시스템에 공통으로 적용될 수 있는 새로운 시각서보 접근방법을 제안하였다. 이 기법은 또한 호모그라피의 물리적 의미를 명확하게 지정할 수 있는 특징을 가진다. Standard visual servoing systems are classified as position-based and image-based visual servo, and both schemes have merits and drawbacks respectively. Recently, Malis et.al. have developed 2.5D visual servoing schemes by exploiting the fact that the interaction between translation and rotation components can be decoupled through a homography. The homography provides Euclidean reconstruction that can be used in the visual servoing, but the physical meaning of the homography is obscure. In this paper, a new visual servoing approach is proposed that can be applied commonly to both the fixed-camera and moving-camera system, using the virtual coordinate frame. The technique also has the characteristic that the physical meaning of the homography is specified explicitly.

정면밀링에서 절삭저항과 표면거칠기에 관한 연구

위금식,정회범 順天大學校 1999 論文集 Vol.18 No.1

In this paper, the cutting resistance and surface roughness in deformed layer were tested for various cutting conditions of face milling. The face milling was performed on carbon steel(SM45C) and austenite stainless steel(STS304) by CNC machining center using 8 blades throw-away tip tool. Experimental tests were carried out by tool dynamometer and surface roughness tester. The results could be summarized ; 1. Cutting resistance in the direction of feed was influenced by depth of cut and cutting speed. 2. Surface roughness was increased at higher cutting speed when feed rate and depth of cut were held constant. 3. The optimal cutting conditions for face milling were 200 m/min cutting speed with 300 mm/min feed rate in SM45C, and 100 m/min cutting speed with 100 mm/min feed rate in STS304.

적외선센서를 이용한 자동높이 조절기

정회범(Hae-Beom Jeong),한병철(Byung-Cheol Han),문상국(Sangook Moon) 한국정보기술학회 2015 Proceedings of KIIT Conference Vol.2015 No.6

렌즈왜곡효과를 보상하는 새로운 hand-eye 보정기법

정회범(Hoi Bum Chung) Korean Society for Precision Engineering 2002 한국정밀공학회지 Vol.19 No.1

북동태평양 KODOS지역 심해 퇴적물의 베인 전단강도 측정 방법에 따른 결과 비교

지상범,정회수,김현섭,문재운,Chi, Sang-Bum,Jung, Hoi-Soo,Kim, Hyun-Sub,Moon, Jai-Woon 한국해양학회 1999 바다 Vol.4 No.4

북동태평양 심해저 생물자원 퇴적물에서 서로 다른 두 종류의 측정기 그리고 선상 및 육상 실험실에서 획득한 베인전단강도(vane shear strength) 자료의 비교 연구를 위하여 다중주상시료 채취기(multiple corer)로 규질 및 탄산질 퇴적물 시료를 채취하였다. 전단강도는 $2.0{\times}2.0$ cm의 베인($90^{\circ}$ four blade vane)이 장착된 수동베인측정기(hand-held vane apparatus, 수동베인) 그리고 회전식 점도계 (rotational viscometer)에 $1.0{\times}0.88$ cm의 베인을 장착하여 구성한 전동베인 측정기(motorized shear vane system, 전동베인)로 측정되었다. 수동베인과 전동베인으로 측정된 전단강도 값들은 코어 깊이에 따라 증가하는 동일한 변화 양상을 보이며, 절대 값도 유의한 차이를 보이지 않는다. 그리고 선상에서 측정된 전단강도 값에 비하여 3개훨월후 실험실에서 동일 장비에 의해 측정한 값들 또한 큰 차를 나타내지 않는다. 한편, 실험실에서 전동베인으로 동일한 코어를 2~4회 반복 측정한 결과 동일한 깊이에서도 측정 지점(hole)에 따라 차이가 나타난다. 또한 한 정점 내에서 서로 다른 코어 시료중 전단강도 값은 상당한 차이를 보이는 경우도 있다. 이는 심해저 주상 퇴적물의 물리적 특성이 생물 교란 작용 등의 영향으로 국부적으로 다르기 때문에 나타난 결과로 판단된다. 즉 심해저 퇴적물의 전단강도는 선상에서 또는 3개월이 지난 후 실험실에서, 그리고 두 종류의 기기를 사용하여도 깊이에 따른 유의한 차이를 보이지 않고, 오히려 한 코어시료 내의 국부적 물성차이 또는 한 정점 내 지점별 물성차이에 의한 변화 폭이 더 크게 나타낸다. Siliceous and calcareous deep-sea core sediments were collected by a multiple corer from the KODOS (Korea Deep Ocean Study) area, northeast equatorial Pacific, to compare vane shear strengths measured by two different apparatuses and in different places of on-board and on-land laboratories. The apparatuses were 1) a hand-held vane with four blades of $2.0{\times}2.0$ cm, and 2) a motorized shear vane system with four blades of $1.0{\times}0.88$ attached on a rotational viscometer. Depth profiles of shear strengths of core samples determined by the apparatuses do not show any consistent difference. Also, there is no consistent difference between shear strength values measured on-board and on-land laboratories after storing the core samples for three months in a cold room by a motorized shear vane system. However, there are considerable differences between depth profiles of shear strengths measured at four different points (holes) of a core sample. Moreover, significant differences among the profiles of different tube samples from a multiple corer within a sampling station were observed. Heterogeneity in physical properties of each depth and sediment column, possibly due to bioturbation and bottom current flows, is likely responsible for the differences in the geotechnical properties.