• Journal of Institute of Control, Robotics and Systems
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• v.4 no.1
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• pp.62-67
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• 1998

Gimballed Inertial Navigation Systems(GINS) are sophisticated autonomous electro-mechanical systems which supply the position, velocity and attitude of the vehicle on which they are mounted. In order to maintain accuracy of outputs, the GINS are required to regularly calibrate senior errors. However, existing calibration methods take up a long time due to multiposition alignments needed to increase accuracy. A particular system formulation for calibration of a GINS is proposed to enhance system observability and thus to expedite calibration procedure. Performance of the proposed calibration method is compared with existing methods such as Schuler test and muliposition alignment. Simulation studies show the proposed system formulation associated with a suggested suboptimal filter is accurate as well as efficient in error identification essential to GINS calibration.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.2
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• pp.32-38
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• 2006

A vehicle adaptive cruise control strategy based on human drivers' driving characteristics has been investigated. Human drivers driving characteristics have been analyzed using vehicle test data obtained from 125 participants. The control algorithm has been designed to incorporate the driving characteristics of the human drivers and to achieve natural vehicle behavior of the controlled vehicle that would reduce the workload of the human driver. Vehicle following characteristics of the cruise controlled vehicle have been compared to real-world driving radar sensor data of human drivers using a validated vehicle simulator. and compare nominal cruise control and adaptive cruise control.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.3
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• pp.99-106
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• 1998

Recently, scientists introduced a new type of microscope capable of investigating nonconducting surfaces in an atomic scale, which is called AFM (Atomic Force Microscope). It was an innovative attempt to overcome the limitation of STM (Scanning Tunnelling Microscope) which has been able to obtain the image of conducting surfaces. Surfaces of samples are imaged with atomic resolution. The AFM is an imaging tool or a profiler with unprecedented 3-D resolution for various surface types. The AFM technology, however, leaves a lot of room for improvement due to its delicate and fragile probing mechanism. One of the room for improvements is gap control between probe tip and sample surface. Distance between probe tip and sample surface must be kept in below one Angtrom in order to measure the sample surface in Angstrom resolution. In this paper, AFM system modeling, experimental system identification and control scheme based on system identification are performed and finally sample surface is measured by home-built AFM with such a control scheme.

• Journal of KSNVE
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• v.7 no.2
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• pp.311-317
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• 1997

In this paper the active vibration control system using a linear oscillatory actuator(LOA) is studied to suppress structural vibration. In the LOA, the AC-power-energized armature generates a shift field in an air gap, which produces a oscillating force to the mover in the magnetic field generated by high density permanent magnets. LOA has relatively simple structure with almost maintenance free, compared with a hydraulic actuator. Performance test of the active vibration control system using a LOA is carried out on a steel test structure under base excitation. From this test, it is confirmed that the acceleration level of the test structure is drastically reduced near the resonant region.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.9
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• pp.1461-1467
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• 2001

This paper proposes a new approach for the ant-swing control of overhead cranes. The proposed control consists of a model-based anti-swing control scheme and a practical path planning scheme. The anti-swing control scheme is designed based on the Lyapunov stability theorem; the proposed control does not require the usual constraints of small load mass, small load swing, slow hoisting speed, and small hoisting distance, but guarantees asymptotic stability while keeping all internal signals bounded. The path planning scheme is designed based on the concepts of minimum-time control and anti-swing control; the proposed path planning generates near-minimum-time trajectories independently of hoisting speed and distance. The effectiveness of the proposed control is shown by computer simulation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.227-229
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• 2002

In this paper, we report on a microstrip line voltage controlled tunable bandpass filter. We used the characteristic the relative dielectric constant of thin film ferroelectrics depends on the applied dr voltage. we designed using Au/BSTO/MgO/Au structure. We cascaded many resonators for large furling range sustaining 1 GHz renter frequency, narrow band, low IL ($\leq$4 dB). We could design the BPF of which center frequency is 16 GHz, 1.9 GHz tuning range, the narrow bandwidth within 800 MHz, low insertion loss less than 3 dB by adjusting the gap of 3 cascaded resonators.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.52 no.5
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• pp.226-226
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• 2003

When an excessive voltage is applied to the discharge gap in ozone generator, the discharge room temperature becomes higher. As is well own, the efficiency of the ozone generation is deteriorated by the excessively hot temperature because of the decomposition reaction. In this paper, the simple small capacity ozone generating controller has been introduced, which provides effective and stable silent discharge characteristics over wide range input power. The proposed power controller has two important advantages, which imply that the production rate of ozone can be controlled linearly according to the delivered power and the surplus energy is recovered to the source. The experimental results are given to verify the performance of the pre proposed controller.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.2
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• pp.226-235
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• 1992

This paper is concerned with the robust control of LQ state feedback regulators with poles in a specified region in the presence of system uncertainty. The robust stability results for the constant and nonlinear time varying perturbations are derived in terms of bounds of the perturbed system matrices and the weighting matrices in the performance index of LQ problem. The theoretical results are applied to the gap control problem of an attractive-type-magnetic levitation system and the effectiveness is proved by the implementation of digital control using 16 bits microcomputer.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2143-2145
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• 2005

Power semicondcutor인 IGBT MOSFET, GTO, SI-Thyristor등은 높은 스위치 신뢰성과 life time, 그리고 fast repetition rate 등을 지니고 있기 때문에 medium/High voltage영역에서 스위치 사용이 대두되어 왔으나, Thyratron이나 Trigatron(Gap switch)와 비교하여 낮은 전압/전류를 스위칭하기 때문에 전통적으로 직렬연결을 통해 high voltage 영역의 스위치로 사용되어 왔다. 하지만, 직렬연결되어 있는 각각의 power semiconductor와 gate driving circuit의 on/off synchronization이 맞지 않기 때문에 부하의 급격한 변화에 따른 전압의 balance에 문제가 가장 심각하게 대두되어 왔다. 이러한 문제를 해결하기 위해서 gate driving circuit에서 제어를 해주는 방법과 power semiconductor에서 제어를 해주는 방법이 있으나 두 방식 모두 문제점이 있다. 본 논문에서는 기존의 zener clamping방식에서 벗어나 새로운 active clamping방식의 직렬연결을 제안했으며 시뮬레이션과 실험을 통해 나타난 이 결과들은 on/off transient 시 symmetry를 유지하는데 효과적이라는 것을 보여주고 있다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.11
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• pp.1733-1740
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• 2004

In the transverse flux linear induction motor(TFLIM) with the general secondary composed of conductor and back-yoke, there exists a magnetized force into the normal direction or the air-gap direction of the thrust motion as well as the thrust force. Therefore, the various methodologies have been tried to use the normal force by the two independent control variables of the multi-phase input. But, as the force depends inevitably and strongly on the thrust force, it is essential to decouple both forces for two control index. In this paper, we suggest a novel approach capable of compensating the couple between both forces and the control index by using the DC-biased multi-phase input, and then realizing the independent control of TFLIM.