• 한국초전도ㆍ저온공학회논문지
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• 제11권2호
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• pp.20-24
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• 2009

In order to explain the operating characteristics of LTMFP in a wide range of driving frequency, an analytical equation that takes into account the detailed behavior of the normal spot is necessary. In this paper, based on the phenomenon of magnetic diffusion of the superconductor we modified the theoretical equations for pumping action in LTMFP. The modified equations explained well the pumping actions under the different load magnets. These results are important to explain the pumping tendency of the LTMFP according to driving frequency.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.671-674
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• 2006

Due to the stricter requests of the human perception of images, many industrial standards such as TCO'03 have been made to survey the Flat Panel Displays (FPD) nowadays. The angular-dependence luminance uniformity is an important item to evaluate the performance of FPD. In this article, we focus on the above test item base on TCO'03 standard in the case of vertical direction of ${\pm}15^{\circ}$. With controlling the driving voltage toward the liquid crystals of TN-type TFT-LCD, there exists a voltage-driving range which can achieve the value of the $L_{max}/L_{min}$ at ${\pm}15^{\circ}\;{\leq}1.7$ readily. Both experiment and simulation have been well analysis.

• 한국전기전자재료학회논문지
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• 제19권12호
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• pp.1099-1105
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• 2006

In this paper, the equivalent circuit model of a Rosen-type multilayer piezoelectric transformer(MPT) has been proposed based on the Mason's equivalent circuit model and the principle of single layer piezoelectric plate. From the piezoelectric direct and converse effects, the symbolic expressions between the electric inputs and outputs of the MPT have been derived from the equivalent circuit model. A simplified equivalent circuit model of the MPT whose driving part has a single input form has been proposed. The symbolic expressions of the driving part have been derived from the simplified equivalent circuit model and the model was compared with the multi-input equivalent circuit model through the simulation. In the comparisons between the simulation results and the experimental data, output voltage is 630 Vp-p in case of 11-layered MPT and 670 Vp-p for 13-layered MPT over the experiment range. As the load resistance increases, output voltage increases and saturates over $300k{\Omega}$ and the resonant frequency changes from 102 kHz to 103 kHz. The simulation and the experimental results agree well over different load resistances and frequencies.

• 자동차안전학회지
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• 제13권1호
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• pp.14-25
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• 2021

This paper presents a RLS based adaptive sliding mode observer (A-SMO) for unknown fault reconstruction in longitudinal autonomous driving. Securing the functional safety of autonomous vehicles from unexpected faults of sensors is essential for avoidance of fatal accidents. Because the magnitude and type of the faults cannot be known exactly, the RLS based A-SMO for unknown acceleration fault reconstruction has been designed with relationship function in this study. It is assumed that longitudinal acceleration of preceding vehicle can be obtained by using the V2V (Vehicle to Vehicle) communication. The kinematic model that represents relative relation between subject and preceding vehicles has been used for fault reconstruction. In order to reconstruct fault signal in acceleration, the magnitude of the injection term has been adjusted by adaptation rule designed based on MIT rule. The proposed A-SMO in this study was developed in Matlab/Simulink environment. Performance evaluation has been conducted using the commercial software (CarMaker) with car-following scenario and evaluation results show that maximum reconstruction error ratios exist within range of ±10%.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2524-2528
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• 2003

High-precision position system is widely used in lots of fields such as semiconductor industry, biotechnology, display and other up-to-date industry field. One of the main issues is to have a long traveling range with precision. There are a few solutions. For instance, there are inchworm methods, lever principle. In this study, we use lever principle to amplify output displacement with a new mechanical amplification structure. We designed new type 3DOF stage with PZT actuator and capacitive sensor. Non-monolithic structure is suggested to obtain the convenience of assembly and modification. Driving parts are designed as modules that generate displacement amplification of each axis. Designed motion module consists of 3 flexure hinges and a PZT actuator with double L lever structure.

• 소음진동
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• 제5권3호
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• pp.403-411
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• 1995

Square beam type piezoelectric vibrating gyro is developed for the measurement of angular velocity, which is compact, small in size and mass- producible. It features that three pieces of piezoelectric ceramics and bonded onto one face of equilateral square bar type gyro head. Two of them are used as sentuators which drive the gyro head and measure Coriolis force. The third piece is used for the feedback signal in order to resonate the gyro head and measure Coriolis force. The third piece is used for the feedback signal in order to resonate the gyro head with its fundamental natural frequency. Matching two fundamental natural frequencies in the gyro head with its driving frequency is found critical in the design of vibration gyro. Calibration results show that the vibrating gyro developed has the dynamic characteristics of first-order system within the frequency range of interest, which can be easily compensated by a lead compensator.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 추계학술대회 논문집 학회본부
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• pp.321-324
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• 1988

This paper presents the result of driving performance analysis of PMSM type AC servo motor based on control system using a microprocessor. The experiment using the microprocessor is tested with a 120[v], 200[w] PMSM type AC servo motor. The PWM signal generated in the microprocessor for the servo motor voltage is chapped by power transistor modules to change the AC servo motor speed. The torque of the AC servo motor with a permanent magnet can be easily controlled over a wide range by changing the AC servo motor current.

• 유공압시스템학회논문집
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• 제4권1호
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• pp.18-24
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• 2007

The continuously variable transmission (CVT) of which speed ratio can change continuously in a fixed range has the benefits of low fuel consumption and exhaust gas because it enables the engine of a vehicle to operate in a high efficiency range regardless of vehicle speed. The speed ratio of belt type CVT is controlled by adjusting line pressure. The one of the line pressure control methods, mechanical-hydraulic control is usually adopting VDT's control method, in which the secondary solenoid valve has two functions both a regulator and a line pressure controller. However, this control method could not show the high performance of CVT with optimal driving capability because of the limitation of simple control algorithm, and it could not gain market share sufficiently in spite of the advantage of CVT with low fuel consumption. On the other hand, the electro-hydraulic control method gives the enhancement of power performance and low fuel consumption by implementing various driving mode using the proportional control or PWM control. The key of CVT technique is to develop a control algorithm of the electro-hydraulic solenoid valve in order to implement the speed ratio efficiently. In this paper, the line pressure control algorithm is proposed and the hydraulic system is controlled using metal belt type CVT test rig and the embedded ECU platform.

• 조명전기설비학회논문지
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• 제14권6호
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• pp.1-5
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• 2000

최근 디지털 텔레비젼전 및 고해상도(High Definition) 텔레비전용 표시장치로 교류형 풀랴즈마 디스플레이가 각광 받고 있다. 상용화되고 있는 교류형 플라즈마 디스플레이의 구조를 보면 3전극행 면방전형(three electrodes surface discharge type)이 주류이다. 재의 효율은 11m/W의 수준으로 본격적인 상용화를 위해서는 효율의 향상이 관건이다. 효율 향상올 위해서는 패널 구조(Panel structure)의 개선도 필요하지만 주어진 구조에서 최대한의 효율을 갖도록하는 구동방법의 최적화가 선결 과제이다. 교류형 플라즈마 디스플레이의 방전 이미지는 연속되는 방전 발광에 의해 이루어 진다. 대부분의 전략 소모는 연속되논 발광을 위한 유지 방전에서 소모되기 때운에 유지방전의 파형의 최적화는 고 방전 효율을 위한 중요한 과제이다. 구동 방식으로서는 ADS(Address and Display period Separated) 구동이라는 방식이 일반적으로 널리 쓰이고 있다. 이 구동법의 평균 유지방전 주파수는 수십 [kHz]이지만 실제 주파수는 100[kHz]에서 200[kHz] 사이의 상당히 높은 값이다. 본 연구 결과에 따르면 형광체가 가시광을 방출시킬 때 형광체 재료의 특성상 감쇄시간(Decay Time)이 수 ms에 이른다. 만약 감쇄 시간이 유지방전 펄스으 주기보다 길다면 방전에서 만들어진 진공자외선(Vacuum Ultra Violet Rav)이 가시광으로 변환애 효과적으로 이용되지 못한다. 결국 발광 효율은 유지방전 주파수에 비례하여 감소한다. 결론적으로 말해 저 주파수 유지 방전으로 발광효율을 크게 개선할 수 있다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제48권5호
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• pp.241-248
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• 1999

Recently, many linear motion generators and motors are rapidly finding applications that ranges from short stroke linear motion vibrators, such as dynamic cone type loudspeakers to stirling engine driven linear reciprocating alternators, compressors, textile machines etc. The stroke-length may go up to 2m, and the maximum speed is in the range of 5 to 10m/s with oscillating frequency as high as 15 kHz. Therefore, the linear oscillating actuators(LOAs) may be considered as variable speed drivers of precise controller with stoke-length and reversal periods during the reciprocating motion. In this paper, the design, fabrication, experiments, and extraction of control parameters of a moving coil type LOA for driving of linear reciprocating motion control systems, are treated. The actuator consists of the NdFeB permanent magnets with high specific energy as the stator produced magnetic field, a coil-wrapped nonmagnetic hollow rectangular bobbin structure, and an iron core as a pathway for magnetic flux. Actually, the design is accomplished by using FEM analysis for the basic configuration of a magnetic circuit, and characteristic equations for coil design. In order to apply as the drivers of a linear motion reciprocating control system, the control parameters and circuit parameters, such as input voltage-stoke, exciting frequency-stoke, coil inductance and so on, are extracted from the analysis and experiments on concerning a fabricating LOA.