• 한국지능시스템학회:학술대회논문집
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• 한국지능시스템학회 2007년도 추계학술대회 학술발표 논문집
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• pp.296-299
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• 2007

본 논문에서는 전기로 합금철 투입 중량을 보다 정밀하게 제어하기 위하여 퍼지 함수를 사용한 제어 기법을 적용하였다. 합금철 중량 제어에 사용된 퍼지 제어는 기존 단순 패턴 제어에 비하여 합금철 계량 정밀도를 높였으며, 합금철 계량 시간을 크게 단축시켰다. 한편 퍼지 제어 함수는 제어수식을 일반화시켜서 Programmable Logic Controller (PLC)의 래더 프로그램으로 구현하였다.

• 한국항공우주학회지
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• 제46권6호
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• pp.487-495
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• 2018

환형 갭과 핀틀갭의 면적을 동시에 제어할 수 있는 가변 슬리브 인젝터의 분무특성을 실험적으로 분석하고, 넓은 추력범위에서 일정한 성능으로 제어할 수 있는 방안을 연구하였다. 슬리브의 개도에 관계없이 일정한 차압을 설정한 경우 설계유량을 만족하지 못하는 것을 확인하였다. 이를 개선하기 위해 개도에 따라 환형 갭과 핀틀 갭에서의 차압을 개도에 따라 다르게 적용하였다. 운용범위 내에서 설계 유량을 만족하였고, 선형적인 슬리브 면적으로 25%에서 100%까지 선형적으로 추력제어가 가능한 것을 확인하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.120.5-120
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• 2002

1. Introduction 2. Property of FPGA 3. Evolvable Hardware (EHW) 4. Genetic Algorithm Processor (GAP) 5. State Machine 6. Conclusion

• 대한전기학회논문지:시스템및제어부문D
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• 제52권6호
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• pp.342-350
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• 2003

In this paper, a levitation controller for a magnetic levitation(MagLev) system is designed and implemented. The target to be controlled is PEM(permanent and electromagnet) type with 4-corners levitation which is open-loop unstable, highly non-linear and time-varying system. The digital control system consists of a VME-based CPU board, AD board, PU board, 4-Quadrant chopper, and gap sensor, accelerometer as feedback sensors. In order to estimate the velocity of the magnet, we used 2nd-order state observer with acceleration and gap signal as input and output, respectively. Using the estimated states, a state feedback control law for the plant is designed and the feedback gains are selected by using the pole-placement method. The designed controller is experimentally validated by step-type gap reference change and force disturbance test.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1995년도 Proceedings of the Korea Automation Control Conference, 10th (KACC); Seoul, Korea; 23-25 Oct. 1995
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• pp.154-157
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• 1995

A magnetic levitation control system is nonlinear and very unstable. Thus there should be a stabilizing compensation network and a feedback path. Due to the levitation control a noncontact photoresistor sensor is generally used. One photocell provides a certain amount of variation in length by the ball shadow casted on the cell surface. Furthermore at the boundary of the cell, the linearity of sensitivity deteriorates severely. To overcome the constraints of the length and linearity, an efficient sensor array is deviced and applied in the feedback path of a large-gap magnetic levitation control system. A number of CdS photocells and a summing circuit of the sensor output signals are used for a sensor array. The levitation length of a ball and the transient performances are main objectives of the large-gap suspension system using the sensor array.

• Journal of Advanced Marine Engineering and Technology
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• 제22권6호
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• pp.888-893
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• 1998

In this paper, we present a magnetic levitation system which has not a gap sensor with sensor-less realization and stabilizing controller design. For measuring gap between magnet and levitated object we propose a gap sensorless method and adop two-degree-of-freedom controller for robust-ness and performence of the magnetic levitation system. From time responeses we confirm that the proposed sensorless method which can be applied to magnetic levitation system. Also the designed stabilizing controller has good disturbance rejection and reference tracking performance.

• 정보저장시스템학회논문집
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• 제5권1호
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• pp.41-46
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• 2009

In SIL-based NFR servo systems, the residual error and the overshoot that are occurred in the process of the modes-witching servo which consists of approach, gap-control modes, and safety mode are reduced by using PID controller. However, the design method of conventional PID controller is not sufficient for the stable air gap control system. Therefore, the optimal PID controller using LQR manner is more useful to find the designed parameters of PID controller. In this paper, we show that the performance of the optimal PID controller is better than that of the lead-lag controller.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.1004-1008
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• 2003

Near-filed optical storage using cantilever aperture tip is a promising way fer next generation optical data storage. To enhance the speed of reading and writing data, gap between tip and media should be controlled fast and precisely within near field region. In this paper, several PZT actuators are analyzed far constructing dual servo control algorithm: coarse actuators(stact. PZT, bimorph PZI) for media surface inclination and One actuator(film PZT) for media surface roughness. Dynamic analysis of stack PZT, bimorph PZT, and film PZT are performed through the frequency response. Based on the frequency response and mathematical model, fast analog controller is designed.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제52권11호
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• pp.535-540
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• 2003

Since axial flux motor has an advantage over more conventional radial flux type motor such as high power density, it can be used as a power train for hybrid electric vehicle and electric vehicle. Also operating range can be extended and efficiency can be improved by changing air gap. Optimal operating air gap is estimated based on the measured efficiency at different air gap. Motor model is developed based on estimated optimal air gap and efficiency. Motor/controller performance is analyzed through simulation. Possible application area of axial flux motor was explored through simulation.

• 한국산업융합학회 논문집
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• 제26권6_2호
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• pp.1127-1134
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• 2023

In this paper, we proposes a study on air gap control for magnetic levitation of transverse flux permanent magnet electromagnets. In general, mechanical systems have a high failure rate of bearings. Bearings in particular are problematic because they have high surface wear rate and degradations. To solve this problem, replacing the bearing with a magnetic levitation electromagnet system can provide lightweight and efficiency improvements. However, precise air gap control is essential to control the magnetic levitation electromagnet system. Therefore, in this paper, we identify the instable cause of gap control through a mathematical modeling and verify through experiment a control algorithm that can use compensation.