• 전력전자학회논문지
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• 제9권6호
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• pp.612-619
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• 2004

회전형 전동기와 볼스크류 및 타이밍 벨트를 이용한 서보 시스템은 NC, 가공기, 로봇 및 공장 자동화를 포함하여 산업 시스템 전반에 널리 사용되고 있다. 하지만, 동력의 전달에서 발생하는 비선형적인 마찰 및 댐핑현상은 제어 시스템 전체의 성능을 감소시키고, 특히 저속 정역 운전에서 그 영향이 크게 나타난다. 본 논문에서는 서보 제어시스템에서 발생하는 비선형적인 마찰 토크의 보상을 위해 가중치를 가지는 이중 제어 구조를 적용하였다. 본 논문에서 제안된 이중 제어 구조는 서보 제어 시스템에서 널리 사용되는 PI 속도 제어기 내부에 비선형적인 마찰 토크의 영향을 보상하는 내부 제어기를 가지는 구조이다. 특히, 내부의 제어기는 마찰 토크에 의한 시스템의 속도오차에 대하여 가중치를 가지는 구조로 설계되어 있고, 제어기의 이득은 외부 속도 제어기의 이득에 대하여 비례적으로 적용되므로, 안정성이 매우 높고 구조가 매우 간단하다. 본 논문에서 제안된 이중 제어 구조에 의한 비선형 마찰 토크 보상 방식은 시뮬레이션 및 실험을 통하여 그 성능을 검증한다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.158-161
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• 2003

Recently, the evolution in production techniques (e.g. high-speed milling), the complex shapes involved in modem production design, and the ever increasing pressure for higher productivity demand a drastic improvement of the dynamic behavior of the machine tool axes used in production machinery. And also machine tools of multi functional and minimized parts are increasingly required as demand of higher accurate in some fields such as electronic and optical components etc. The accuracy and the productivity of machined parts are natural to depend on the linear system of machine tools. The complex workpiece surfaces encountered in present-day products and generated by CAD systems are to be transformed into tool paths for machine tools. The more complex these tool paths and the higher the speed requirements, the higher the acceleration requirements are needed to the machine tool axes and the motion control system, and the more difficult it is to meet the requirements. The traditional indirect drive design for high speed machine tools, which consists of a rotary motor with a ball-screw transmission to the slide, is limited in speed, acceleration, and accuracy. The direct drive design of machine tool axes. which is based on linear motors and which recently appeared on the market. is a viable candidate to meet the ever increasing demands, because of these advantages such as no backlash, less friction, no mechanical limitations on acceleration and velocity and mechanical simplicity. Therefore performance tests were carried out to machine tool axes based on linear motor. Especially, dynamic characteristics were investigated through circular test.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.2430-2434
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• 2005

Automatic FPC punching instrument for the improvement of working condition and cost saving is introduced in this paper. FPC(flexible printed circuit) is used to detect the contact position of K/B and button like a cellular phone. Depending on the quality of the printed ink and position of reference punching point to the FPC, the resistance and current are varied to the malfunctioning values. The size of reference punching point is 2mm and the above. Because the punching operation is done manually, the accuracy of the punching degree is varied with operator's condition. Recently, The punching accuracy has deteriorated severely to the 2mm punching reference hall so that assembly of the K/B has hardly done. To improve this manual punching operation to the FPC, automatic FPC punching system is introduced. Precise mechanical parts like a 5-step stepping motor and ball screw mechanism are designed and tested and low cost PC camera is used for the sake of cost down instead of using high quality vision systems for the FA. 3D Mechanical design tool(Pro/E) is used to manage the exact tolerance circumstances and avoid design failures. Simulation is performed to make the complete vision based punching machine before assembly, and this procedure led to the manufacturing cost saving. As the image processing algorithms, dilation, erosion, and threshold calculation is applied to obtain an exact center position from the FPC print marks. These image processing algorithms made the original images having various noises have clean binary pixels which is easy to calculate the center position of print marks. Moment and Least square method are used to calculate the center position of objects. In this development circumstance, Moment method was superior to the Least square one at the calculation of speed and against noise. Main control panel is programmed by Visual C++ and graphical Active X for the whole management of vision based automatic punching machine. Operating modes like manual, calibration, and automatic mode are added to the main control panel for the compensation of bad FPC print conditions and mechanical tolerance occurring in the case of punch and die reassembly. Test algorithms and programs showed good results to the designed automatic punching system and led to the increase of productivity and huge cost down to law material like FPC by avoiding bad quality.