• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1998년도 춘계학술대회논문집; 용평리조트 타워콘도, 21-22 May 1998
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• pp.233-237
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• 1998

In this work, to identify the dynamic characteristics of disk-spindle system in hard disk drive, experimental modal analysis was performed. And an experimental analysis system including testing apparatus, precision sensors, and analysis software was established in order to perform the testing effectively. From the experimental results, coupled and uncoupled modal characteristics of 3-disk spindle system are clearly identified.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1994년도 추계학술대회 논문집
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• pp.455-459
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• 1994

One relay control implementation to the servo control systepm is contrlved mainly for the high power electric or electro hydraulic type drive system. Proposed SERME control is relay emulated software scheme accounting a reay producing maximum torque in both direction in the insufficient bandwidth control system. Possibillty is proposed mathematically prlor to emperical work out.

• Journal of Power Electronics
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• 제14권1호
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• pp.115-124
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• 2014

This paper presents the implementation of two-arm modulation (TAM) technique for the independent control of a two-induction motor drive fed by a five-leg inverter (FLI). A carrier-based space vector pulse width modulation technique for TAM is proposed to generate switching signals for FLI. Two independent three-phase space vector modulators are utilized to control two motors. The motor drive system applies two separate indirect field-oriented control methods. The stationary voltage outputs from the vector control are synthesized in the three-phase space vector modulator to generate switching signals for FLI. The performance of the independent control of the motors and the voltage utilization factor are likewise analyzed. Simulation and experimental results verify the effectiveness of the proposed method for the independent control of the two-motor drive system. The proposed technique is successfully validated by dSPACE DS1103 experimental work.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 Proceedings of the Korea Automatic Control Conference, 11th (KACC); Pohang, Korea; 24-26 Oct. 1996
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• pp.315-318
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• 1996

In this paper a new positioning method for cylindrical work pieces on rotating supports is studied. A work piece on a rotating axis is positioned by an impact drive mechanism (IDM) whose driving parameters are steadily updated by observing the object movement. The application of this actuator and the use of a multi-functional PC board for all necessary input and output operations such as e.g. data acquisition or wave form generation allow an alignment with a precision of less than 1.mu.m in a relatively short time and at low cost compared to conventional methods.

• Tribology and Lubricants
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• 제17권1호
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• pp.1-9
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• 2001

Hard disk drives operate in various environmental conditions. Thus, it is necessary to assess the reliability of the head/disk interface under these conditions. In this work, stiction and acoustic emission signals were investigated under different temperature, humidity, and ambient pressure conditions. Also, track average amplitude was observed for disk failure in N$_2$environment. It is shown that failure of the head/disk interface occurs more readily at high temperature and low ambient pressure conditions.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.675-677
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• 2004

This paper presents a nonlinear controller design for optical disk drive systems to improve anti-shock performance. The nonlinear anti-shock controller is added parallel to the original linear servo control loop. In the previous work, dead-zone nonlinear element is used for nonlinear controller and PID control method is used for linear controller. Although this strategy improves anti-shock performance, it has a narrow stability bound. In this paper, we propose dead-zone with saturation nonlinear element for the nonlinear controller. Since this nonlinear element improves stability margin, we can use higher gain of dead-zone than the controller with dead-zone only. In the linear controller design, we show that lead-lag control has improved stability margin over PID control. Numerical simulation results show that the proposed method can get better performance to the external shock than previously proposed method.

• 전력전자학회논문지
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• 제16권6호
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• pp.554-560
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• 2011

단일 주파수로 유도가열에 의한 표면 경화 열처리 공정에서 생기는 설비의 이중 투자 문제 및 열처리 공정시간을 단축할 수 있도록 하기 위해 하나의 공정에서 두가지 공정을 동시에 처리할 수 있도록 해주는 동시 이중 주파수(Simultaneous dual frequency: SDF) 구동기법 기술에 대해 설명한다. 본 논문에서는 듀얼 방식의 인버터를 제안하여 이중 주파수(Dual frequency) 구동기법을 구현하였으며 시뮬레이션과 실험을 통해 제안된 인버터의 이중 주파수제어 및 전력제어를 검증하였다.

• 한국산업정보학회논문지
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• 제24권5호
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• pp.121-127
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• 2019

본 논문에서는 물류창고, 제조업, 협업 로봇 등 다양한 애플리케이션에 활용되고 있는 비홀로노믹 제약을 가진 차동 바퀴형 모바일 로봇의 용이한 운용을 위한 로컬 속도 생성 제어 알고리즘을 제안한다. 기존의 차동 바퀴형 모바일 로봇 운용 방법은 운용자가 자신의 좌표계가 아닌 로봇의 좌표계를 기준으로 인지하고 로봇의 속도를 직접 생성해야 하였으며, 이로 인해 운용의 직관성이 낮아지고 업무의 효율 저하 및 사고 발생률이 증가하게 된다. 본 연구에서는 이를 개선하여 운용자가 자신의 좌표계를 기준으로 로봇을 운용할 수 있도록 한다. 제안하는 알고리즘은 실제 차동 바퀴형 모바일 로봇을 활용한 실험을 통하여 알고리즘의 효용성을 검증한다.

• Journal of Power Electronics
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• 제3권1호
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• pp.49-54
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• 2003

A novel control scheme of using a single electronic drive to synchronize two synchronous motors is investigated analytically. The developed control strategy extends the conventional vector control technology, Specifically, it utilizes the property that the motion of two motors can be independently controlled by the q-axis currents provided the desired q-axis currents can be achieved by adjusting physical armature currents. The latter part is indeed guaranteed by adding a position offset to one of the motors. This work has a potential of cost saving in practice where the cost of drive is a major concern.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2001년도 제33회 춘계학술대회 개최
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• pp.122-126
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• 2001

Magnetic hard disk drive is continually being pushed to reduce head-disk spacing for higher recording densities. The current minimum spacing between the air-bearing slider and disk has been reduced to under 15 nm. In this work, it was investigated if flying height could be lowered under the height of laser bumps. With the reduction of the spinning speed, the flying height was decreased under the height of laser bumps. When a head swept between landing zone and data zone, the head-disk impact was monitored using AE and friction signals. It is demonstrated that magnetic hard disk drive could be operated without tribological failures under the height of laser bumps.