• International Journal of Control, Automation, and Systems
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• 제4권1호
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• pp.1-9
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• 2006

This paper presents the modeling and multivariable feedback control of a novel high-precision multi-dimensional positioning stage. This integrated 6-degree-of-freedom. (DOF) motion stage is levitated by three aerostatic bearings and actuated by 3 three-phase synchronous permanent-magnet planar motors (SPMPMs). It can generate all 6-DOF motions with only a single moving part. With the DQ decomposition theory, this positioning stage is modeled as a multi-input multi-output (MIMO) electromechanical system with six inputs (currents) and six outputs (displacements). To achieve high-precision positioning capability, discrete-time integrator-augmented linear-quadratic-regulator (LQR) and reduced-order linearquadratic-Gaussian (LQG) control methodologies are applied. Digital multivariable controllers are designed and implemented on the positioning system, and experimental results are also presented in this paper to demonstrate the stage's dynamic performance.

• Journal of international Conference on Electrical Machines and Systems
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• 제1권2호
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• pp.3-9
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• 2012

The paper describes a novel technique for on line parameter identification of three-phase induction motors from a single, run up to speed test. Data is sampled during this test with the normal locked rotor and synchronous speed data captured on the way to reaching the motor's rated speed. Rotor parameter variations with frequency due to skin and proximity effects and other non-linear imperfections such as heating and main flux path saturation are taken into account. This method is ideal for determining and/or verifying parameters used in high performance drives.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2001년도 학술대회 논문집
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• pp.159-162
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• 2001

A Stirling cryocooler is relatively compact, reliable, commercially available, and uses helium as a working fluid. The FPFD stirling cryocooler consists of two compressor pistons driven by linear motors which makes pressure waves and a pneumatically driven displacer piston with regenerator. It is the most suitable design for a mechanical cryocooler utilized in night vision environment. In order to get optimum operating frequency, natural frequency of piston and displacer, optimum phase angle between piston and displacer, cooling capacity, performance tests of the Stirling cryocooler by the frequency characteristics were performed.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2001년도 학술대회 논문집
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• pp.33-36
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• 2001

A free piston and free displacer(FPFD) Stirling cryocooler for cooling infrared and cryo-sensors is currently under development at KIMM(Korea Institute of Machinery & Materials). The FPFD Stirling cryocooler employs 1) the Stirling cycle for refrigeration, 2) linear motors for driving the cryocooler, 3) spring and gas support systems, and 4) fine gap for clearance seals. It is the most suitable design for a mechanical cryocooler utilized in night vision environment. The experimental results show KIMM-E1 Stirling cryocooler (with expander manufactured by KIMM) has the higher cooling power and faster response time at optimum charging pressure.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 하계종합학술대회 논문집
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• pp.40-43
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• 1989

In recent years, Levitated transportation systems have been studied in many countries, Most vehicles used for these systems are driven by linear motors and are levitated magnetically. The magnetic train HDMAG-01 is a proto-type vehicle for low-speed in the range of 100cm/S. This paper presents an outline of the drawing, the testing and its results, describes theoretical models used and compares between computer simulation and test result.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 학술대회 논문집 정보 및 제어부문
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• pp.228-230
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• 2005

In this paper, we address an active vibration control system, which suppresses the vibration engaged by magnetically levitated stage. The stage system consists of a levitating platen with four permanent magnetic linear synchronous motors in parallel. Each motor generates vertical force for suspension against gravity and propulsion force horizontally as well. This stage can generate six degrees of freedom motion via the vertical and horizontal forces. In the stage system, which represents the settling-time critical system, the motion of the platen vibrates mechanically. We designed an active vibration control system for suppressing vibration due to the stage moving. The command feedforward with inertial feedback algorithm is used for solving stage system's critical problems. The components of the active vibration control system are accelerometers for detecting stage tables's vibrations, a digital controller with high precise signal converters. and electromagnetic actuators.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1996년도 추계학술대회 논문
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• pp.34-39
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• 1996

In many industrial applicatiosns such as machine tools and automation equipments the control performance of the feed-drive systems as positioning devices of the tools and workpieces have great influences on the quality of related machines. For many electrically driven mechanical feed systems resilient couplings between motors and mechanical elements which mostly consist of elasttic shafts and gears often are unavoidable. Commonly these systems can be regarded as an elastic multi-mass systems can be regarded as an elastic multi-mass system which is dealt with this contribution. S high performance speed or position control can only be achieved with the considering of the mechanical elastic characteristics of the system. n this paper some practic characteristics of the system In this paper some practical information is given about experience in modeling design simulation and experiments for linear elastic multi-mass system,

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.1599-1604
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• 2007

LIMs propelling the MAGLEV which has been developed in Korea have 3-series and 2-parallel connection, so that 6 LIMs per one vehicle are fed by one inverter. Thrust performance of the parallel-operated LIMs can be different from each other because of variant magnetic air gaps and electrical impedance. The thrust difference between the parallel LIMs cause a twist force on the vehicle. This paper proposes an algorithm to measure thrust of the parallel-operated LIMs. The method uses a digital signal processor(TMS320F2812), voltage and current sensors. As a result, thrust, flux and currents of the parallel-operated small LIMs which are manufactured in our laboratory are monitored by the developed measurement system.

• 한국정밀공학회지
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• 제7권1호
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• pp.63-73
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• 1990

Low cost automatic welding machine is developed for the purpose of welding process automation of automobile parts with two dimensional welding joints. Developed gantry type machine is equipped with X, Y and roll axis stepping motors, and dirive units units are designed by two phase on drive scheme using shift registers. Control system is constructed by single board microcomputer of Z80A CPU, and also it is equipped with parallel input output ports and counter-timer chips. Linear and circular interpolation of welding head movement is accomplished by employing software digital differential analyzers. It has been shown that contour error of develped system is withi ${\pm}1.0mm$, meaning that the machine is suitable for CO2 arc welding process of automoble parts and is expected it's application to industry.

• 한국음향학회:학술대회논문집
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• 한국음향학회 2001년도 추계학술발표대회 논문집 제20권 2호
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• pp.193-196
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• 2001

본 연구에서는 원활한 정재파 생성과 양방향 구동이 가능한 새로운 형태의 초음파 리니어 모터를 제작하고, 그 특성을 평가하였다 본 연구에서 제안한 모터는 $\lambda/4$ 간격으로 이빨 구조를 가지는 스테이터의 상, 하부에 압전소자를 $90^\circ$ 의 위치 위상차를 갖도록 부착한 형태의, 상, 하부 압전소자에 각각 동위상, 180도의 시간 위상차를 가지는 교류 전압을 인가함으로써 양방향 구동이 가능하도록 하였다. 또한 원활한 정재파를 생성할 수 있는 최적의 구조를 결정하기 위해, 여러 가지 형태의 경계조건들에 대해 유한요소해석법을 이용하여 모델링하여 각 이빨들의 변위를 관찰함으로써 각각의 구조에 대해 타당성을 검증하였다. 위 결과를 바탕으로 세 종류의 초음파 리니어 모터를 제작하여 구동실험을 하였고, 실험 결과에 따라 속도와 추력 및 양방항성이 가장 우수한 최적의 구조를 결정하였다. 본 연구에서 제작한 모터는 최대 82.4cm/s의 속도와 0.46N의 추력을 가졌다.