• 제어로봇시스템학회:학술대회논문집
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• 1993.10b
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• pp.9-23
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• 1993

Free-form surface machining is usually performed with an NC milling machine and a ball end milling cutter. Since this conventional method is basically sculpting on a plane, it is not suitable for three dimensional body machining. This article will introduce a new machining method for three dimensional body with free-form surface and newly developed machine tool suitable for such machining.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.656-658
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• 1992

Electronically controlled magnetic bearings offer two major advantages over conventional ball bearings: there is no mechanical wear, and the shaft position is under precision control. The former characteristic is useful in rotary systems, which require reliability under maintenance-free conditions. In this paper, we introdue development tendency and technology of magnetic bearing.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.76-79
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• 1999

A study on simulation using Matlab shows the dynamic condition of a beam on feed-back with encorder. A controller for rapid response interpreted the stability on simulation with pole-placement technique. The effect of response was considered feed-back gain. The result of feed-back is described that various feed-back coefficient shows stable controll systems. It would be expected each result according to controllers.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.84.4-84
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• 2002

$\textbullet$ To achieve 3 high power-to-weight ratio, design of 3DOF hip module $\textbullet$ Using parallel mechanism and linear actuator consist of a ball-screw mechanism $\textbullet$ The kinematics analysis for the hip module $\textbullet$ A kinematic index to measure actuator power are introduced. $\textbullet$ It is demonstrated throught simulation that incorporation of redu ndant actuator into the hip module

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.36.6-36
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• 2002

$\textbullet$ Human motion consists of continual impact with environment $\textbullet$ External impulse model of kicking motion $\textbullet$ Models of aerodynamic forces $\textbullet$ Analysis of external impulse according to posture $\textbullet$ Simulation of a soccer ball trajectory

• Journal of the Korean Society for Precision Engineering
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• v.9 no.4
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• pp.58-64
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• 1992

이 논문에서는 Hoop속에 Ball이 구르는 간단한 전기 기계 구동 장치를 고려 하였다. 이 장치의 구조는 간단하지만 원유수송선과 같은 대형 액체를 고속 수송할 때 발생되는 "liquid slop"문제를 해석하고 제어하는데 좋은 모델이 된다. 본 연구에서는 liquid slop dynamics를 언급 하였고, 이러한 시스템을 제어 하기 위하여 재래식 PID, state-feedback 알고리즘의 유용성을 검토하였고 하이브리드 제어방식을 제안하였다. 하이브리드 제어방식이 다른방식보다 성능면에서 다소 우세함을 알 수 있었다.을 알 수 있었다.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.7
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• pp.141-146
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• 2000

A flexible tool is developed for automatic finishing of curved surfaces without any complicated control technique on three-axes machining center. The tool is made of thermosetting polyurethane elastomer on the surface of which aluminum oxide abrasives are mounted. Performance and durability of the tool are examined by finishing ball-end milled surfaces of high-alloyed tool steel. It is demonstrated that the tool removes cusp successfully without changing overall surface shape in relatively short time.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.11a
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• pp.205-211
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• 2000

Friction control is highly desirable for optimization of tribological systems. In this work, the effect of geometric structure of the solid surface on friction is investigated using a Scanning Electron Microscope equipped with a tribotester. Silicon and silicon oxide specimens were used and undulations on the surface were fabricated by mechanical and chemical methods. It is shown that the friction coefficient depends on the relative dimensions of the ball and the width of undualation. By optimizing the geometry of the undulation, friction reduction may be achieved.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.87.5-87
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• 2001

In the past, we presented the tracking system with one sampling delay. In this paper, first we propose a tracking system with N-th sampling delay, in the case where an input-output pulse transfer function of a plant Z$\_$-N/. Secondly we propose a system configuration converting an input-output pulse transfer function of a plant into Z$\_$-N/ with the inverse system of the plant. Moreover, the proposed tracking system configuration is applied to an actual Ball and Beam system and good results are obtained.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.3
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• pp.41-49
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• 2010

Two promising control candidates have been selected to test the sinusoidal reference tracking performance for a brush-type polishing machine having strong nonlinearities and disturbances. The controlled target system is an oscillating mechanism consisting of a common positioning stage of one degree-of-freedom with a screw and a ball nut driven by a servo motor those can be obtained commercially. Beside the strong nonlinearity such as stick-slip friction, the periodic contact of the polishing brush and the work piece adds an external disturbance. Selected control candidates are a Sliding Mode Control (SMC) and a variant of a feedback linearization control called Smooth Robust Nonlinear Control (SRNC). A SMC and SRNC are selected since they have good theoretical backgrounds, are suitable to be implemented in a digital environment and show good disturbance and modeling uncertainty rejection performance. It should be also noted that SRNC has a nobel approach in that it uses the position information to compensate the stickslip friction. For both controllers analytical and experimental studies have been conducted to show control design approaches and to compare the performance against the strong nonlinearity and the disturbances.