• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.3
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• pp.133-138
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• 2022

Digital radiation inspection equipment is a medical device that deals with human life and requires stability and high reliability. However, this system is currently the most advanced technology and the domestic market is almost occupied by European products including Japan. Therefore, research and development are needed not only to replace domestic medical devices, which are largely dependent on expensive imported products, but also to develop more economical and user-oriented products that are easy to operate and produce devices that lead to accurate diagnosis. In particular, among the digital X-ray systems, the motor driving technology and the mechatronics technology related to the development of mechanical devices have matured to some extent in Korea. In this paper, selection of AC servomotor for digital radiation inspection suitable for imaging purpose, and application of conversion device and control method to check performance and improve problems.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.252-252
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• 2000

The Resistance Spot Welding (RSW) has been considered as an inherently safe and reliable method far joining metals, and has been widely employed, especially in automobile body assembly shops, as a manufacturing process. In recent years, the requirement for more sophisticated quality control procedures has considerably grown in the mass production industries. The object of the application of servo control to spot welding gun is the improvement of quality control in the spot welding, one of conventional industrial areas. The important factors affecting welding qualities (shear strength, nuggest size, indentation depth) are welding current, welding time, and gun press force. Welding current and welding time are controlled by welding timer. But, the conventional welding guns using compressed air are out of control in changing gun press forces in welding process. In this paper, a servo gun welding system having a AC servo motor and a PC control system is presented. The main object of this paper is to estimate the influence of gun press force changes in the welding process (press time -> welding time -> hold time) to welding qualities, and to evaluate welding qualities in real time, by recognizing the patterns of gun press forces changed in the welding process and comparing with the standard patterns.

• Proceedings of the KIEE Conference
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• 1998.07b
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• pp.541-543
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• 1998

Generally, PI control is simple and easy to implement and gains of PI control are determined by specifying a dynamics of the servo driver system. However, the gain-tuning is so difficult that it is relied on an expert's effort. This paper presents a gain auto-tuning method for PI controllers based on a fuzzy inference mechanism. First, the proposed fuzzy inference system identifies a system moment of inertia and adjusts control gains by using the difference in speed responses between a real plant and a reference model. Second, this paper proposes an improved fuzzy PI controller. To reduce the speed overshoot, we adapt a control method that selects a proper PI gains with respect to the load inertia variation. To prove the validity of the proposed gain tuning algorithm and the feasibility of the servo drive, a high performance servo drive will be implemented by DSP(TMS320C31) and intelligent power module (IPM). The proposed controller is applied to the speed control of the 300W AC servo motor. Some simulations and experimental results show that the proposed fuzzy PI controller is more robust than the conventional PI controller against the load inertia variation.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.314-317
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• 1996

In this paper, we present a nonlinear adaptive controller for position tracking of induction motors. In constructing the adaptive controller, a backstepping approach is used under the condition of full state information, while a nonlinear observer is adopted for rotor flux estimation. The adaptive controller is shown to drive the state variables of system to the desired ones asymptotically and whose effectiveness is also shown via computer simulation.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.312-316
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• 1987

A simple hybrid circuit to control the two-phase AC motor of the nut-runners which employ the tightening torque control system is described in this paper. The circuit has emphasis on the low-cost implementation. The circuit constitutes of the V/F converter using a timer IC, the pulse width modulator using the fastening torque signal and the two-phase logic sequencer.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.406-407
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• 2018

본 논문에서는 SPMSM의 속도 및 전류제어기를 PI 혹은 I-P제어기를 조합한 네 가지 형태의 제어시스템으로 구성하여 서보시스템에 가장 적합한 형태의 제어시스템 구성과 설계기법을 도출하고, 시뮬레이션 해석을 통해 유효성을 검증한다.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.343-346
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• 2007

Recently, many nations have released standard such as EN61000-3-2 to impose a limit on the harmonic current to prevent distortion of AC line and to save energy. Also, the limit on the harmonic current makes use of a trade barrier. Therefore, Power factor correction must have been suitable for a limit on the harmonic current. This paper presents AC servo motor drive to have merits of high power factor for Desk-Top Robot.

• Proceedings of the KIEE Conference
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• 1990.11a
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• pp.10-14
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• 1990

Variable Structure System(VSS) la being extended to a new control system of ac servo machines for its merits of simple mechanism and robustness. This paper has studied about applying VSS to position control for brushless servo motor. But VSS has the chattering problem of control input. This chattering phenomenon cause acoustic noises, torque ripple and increase harmonics of the current. One of the useful way to eliminate this defect of VSS, linearlizing the switching function is discussed here. Though the conventional method of linearizing the switching function diminishes the chattering, it may degrade the robustness of the system. In this paper, new linearized switching function which shows robust performance to the parametric variation and reduces chattering simultaneously is introduced and assured by simulation.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.422-428
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• 2002

In this study, actuator, sensor, guide, power transmission element and control method are considered for ultra-precision positioning apparatus. Through previous process, single plane X-Y stage with ultra-precision positioning is manufactured. Global stage for the purpose of materialization with robust system, is combined by using AC servo motor and ball screw and rolling guide. And ultra-precision positioning system is developed by micro stage with elastic hinge type and piezo element. global servo and micro servo for the purpose of materialization positioning accuracy with nm(nanometer) are controlled simultaneously by using incremental encoder and laser interferometer as displacement measurement sensor. Through previous process, ultra-precision positioning system (100mm stroke and ${\pm}$ 10nm positioning accuracy) with single plane X-Y stage are materialized.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.5
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• pp.65-72
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• 2002

In this study, actuator, sensor, guide, power transmission element and control method are considered for ultra-precision positioning apparatus. Through previous process, single plane X-Y stage with ultra-precision positioning is manufactured. Global stage for the purpose of materialization with robust system, is combined by using AC servo motor and ball screw and rolling guide. And ultra-precision positioning system is developed by micro stage with elastic hinge type and piezo element. global servo and micro servo for the purpose of materialization positioning accuracy with nm(nanometer) are controlled simultaneously by using incremental encoder and laser interferometer as displacement measurement sensor. Through previous process, ultra-precision positioning system(100mm stroke and $\pm$ l0nm positioning accuracy) with single plane X-Y stage are materialized.