• 한국정밀공학회지
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• 제10권4호
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• pp.200-205
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• 1993

In many applications, the typical parallel-jaw end-effector of a robot arm has been remarkably satisfactory. But, it is not adequate for the applications such as complicated manipulation. In the study, a finger with 4 joints (so, having redundancy) was consturcted to investigate the characteristics of an articulated hand. Each joint was driven by one actuator, and the motor torque was transmited to each joint through a tendon-pulley system. In the context, major considerations for hardware design and the method to solve the inverse kinematics of a redundant manipulator were presented. Finally, the basic capabilities of an articulated hand were presented through experiments.

• 한국정밀공학회지
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• 제10권2호
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• pp.30-39
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• 1993

The study is concerned with the thermo-viscoplastic finite element analysis of nonisothermal hot container extrusion through conical dies. The problem is treated as a non-steady state incorporating the nonisothermal heat transfer analysis. The analysis of temperature distribution includes heat transfer though the boundary surface including conduction, convection and radiation. The analysis of heat transfer is decoupled with the analysis of deformation and the material interaction is considered through iteration procedure. The effect of important process parameters including die angle and extrusion ratio in the process is investigated. Due to the geometric feature for the container extrusion through conical dies, automatic remeshing is mandatory. Automatic remeshing is achieved by introducing the modular remeshing technique.

• 한국정밀공학회지
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• 제10권1호
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• pp.77-88
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• 1993

In this paper, we propose a stereo vision system to solve correspondence problem with large disparity and sudden change in environment which result from small distance between camera and working objects. First of all, a specific feature is divided by predfined elementary feature. And then these are combined to obtain coded data for solving correspondence problem. We use Neural Network to extract elementary features from specific feature and to have adaptability to noise and some change of the shape. Fourier transformation and Log-polar mapping are used for obtaining appropriate Neural Network input data which has a shift, scale, and rotation invariability. Finally, we use associative memory to obtain coded data of the specific feature from the combination of elementary features. In spite of specific feature with some variation in shapes, we could obtain satisfactory 3-dimensional data from corresponded codes.

• 한국정밀공학회지
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• 제12권1호
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• pp.58-67
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• 1995

A path planning algorithm using a laser range finder are presented for real-tiem navigation of an autonomous guided vehicle. Considering that the laser range finder has the excellent resolution with respect to angular and distance measurements, a sophisticated local path planning algorithm is achieved by using the human's heuristic method. In the case of which the man knows not rhe path, but the goal direction, the man forwards to the goal direction, avoids obstacle if it appears, and selects the best pathway when there are multi-passable ways between objects. These heuristic principles are applied to the path decision of autonomous guided vehicle such as forward open, side open and no way. Also, the effectiveness of the established path planning algorithm is estimated by computer simulation in complex environment.

• 한국전자통신학회논문지
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• 제19권1호
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• pp.181-188
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• 2024

정밀 설비 기술의 발전으로 4축 CNC 정밀 가공 기술의 중요성이 증대되고 있다. 그러나, 복잡한 형상 가공으로 인해 시스템 구동은 어려운 실정이다. 본 논문은 이러한 문제를 해결하기 위해 4축 제어 구조물을 제작하고, 상용 프로그램을 이용없이 Bresenham's Line Algorithm과 Runspeed Algorithm을 구현하여 정밀 제어 및 효율성을 비교하였다. Runspeed를 적용할 경우 Bresenham 대비 약 12.03%의 오차 개선과 곡률 정밀도 향상이 있었으며, 회전축 A모터를 구동하여 입체 구조물에도 정밀한 가공이 가능함을 확인하였다.

• 한국정밀공학회지
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• 제13권3호
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• pp.56-62
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• 1996

This paper presented a new measuring system to improve circular motion accuracy by using two-dimensonal probe and master ring for NC machine tools. This measuring system reduced the circular motion error conspicuously by eliminating the influence of the acceleration/deceleration range and compensating the friction force whose influences were significant while measuring the motion. Experimental results show that this system had enough accuracy to measure a circular motion for NC machine tools, compared with the circular test method and the r .theta. method.

• 한국정밀공학회지
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• 제12권11호
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• pp.148-158
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• 1995

This paper describes a hierarchical structure for feature definition and classification, and feature representation method based on frame structure for process planning of prismatic machined components of injection mold. The concept of Volume Removal Directions and Vertical Faces is proposed to develop a method to define and to classify features for components of injection mold systematically. A method for classifying features by the combination of volume removal directions and vertical faces is developed, and also a feature representation method by using frame structure to represent design and manufacturing information is presented.

• 한국정밀공학회지
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• 제4권3호
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• pp.12-18
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• 1987

오늘날 국내외에서의 FA(Facorty Automation)에 관한 움직임이 활발해진 것 같다. 공업선진국에서는 새 FA에 관한 Project가 탄생, 기초적인 연구개발의 진첩이 이루어지고 있다. 여기선 한국정밀공학회의 개별회원 및 단체 회원을 위하여 특히, 최근 주목되고 있는, 통합화(CIM), 지능화(Intellgence)및 표준화에의 동향에 대해서 그 개관을 소개하고져 한다.

• 방송공학회논문지
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• 제28권1호
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• pp.21-30
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• 2023

컴퓨터 생성 홀로그래피는 일반 이미지에 비해 연산 부하와 메모리 요구량이 크다. 본 논문은 정밀도를 낮추어 연산속도를 높이는저정밀도(low-precision) 및 혼합정밀도(mixed precision) 연산 방법을 회절연산에 적용하여, 정밀도에 따른 홀로그램의 생성 속도와 품질의 변화를 분석한다. 본 논문은 배정밀도, 단정밀도, bfloat16 정밀도에서의 회전 연산을 비교하였으며, bfloat16의 회절연산의 속도가 배정밀도에 비해 최대 5.94배, 단정밀도에 비해 1.52배 빠른 것을 확인하였다. 또한, MSE, PSNR, SSIM을 기준으로 회절 연산의오차를 측정하였으며, 정밀도가 낮아질수록 홀로그램 품질이 낮아지는 것을 확인했다. 하지만, 정성적인 이미지 품질에는 유의미한 영향이 없는 것을 확인했다. 이러한 결과는, bfloat16등 낮은 정밀도 연산의 홀로그램 연산으로의 적용 가능성을 보여준다.

• 한국정밀공학회지
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• 제17권12호
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• pp.26-33
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• 2000