• 한국가시화정보학회지
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• 제8권2호
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• pp.31-39
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• 2010

Hysteresis is an effect by which the order of previous events influences the order of subsequent events. Hysteresis phenomenon of supersonic internal flows with shock waves has not yet been clarified satisfactorily. In the present study, experiments are carried out on internal flow in a supersonic nozzle to clarify the hysteresis phenomena for the shock waves. Flow visualization is carried out separately on the straight and divergent channels downstream of the nozzle throat section. Results obtained were compared with numerically simulated data. The results confirmed hysteresis phenomenon for shock wave in the Laval nozzle at a certain specific condition. The relationship between hysteresis phenomenon and the range of the rate of change of pressure ratio with time was shown experimentally. The existence of hysteretic behavior in the formation, both the location and strength, of shock wave in the straight part of the supersonic nozzle with a range of pressure ratio has also been confirmed numerically.

• Journal of Mechanical Science and Technology
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• 제18권10호
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• pp.1755-1762
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• 2004

Friction phenomenon can be described as two parts, which are the pre-sliding and sliding regions. In the motion of the sliding region, the friction force depends on the velocity of the system and consists of the Coulomb, stick-slip, Streibeck effect and viscous frictions. The friction force in the pre-sliding region, which occurs before the breakaway, depends on the position of the system. In the case of the motion of the friction in the sliding region, the LuGre model describes well the friction phenomenon and is used widely to identify the friction model, but the motion of the friction in the pre-sliding such as hysteresis phenomenon cannot be expressed well. In this paper, a modified friction model for the motion of the friction in the pre-sliding region is suggested which can consider the hysteresis phenomenon as the Preisach model. In order to show the effectiveness of the proposed friction model, the sliding mode controller (SMC) with hysteresis friction compensator is synthesized for a ball-screw servo system.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2017년도 제48회 춘계학술대회논문집
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• pp.609-611
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• 2017

최근 다양한 산업 및 공학 응용분야에서 히스테리시스 현상이 자주 발생하며, 이에 대한 많은 관심과 연구가 수행되었다. 이러한 현상은 주로 압력비가 일시적으로 변화하는 과정에서 발생되며, 초음속 풍동 시동과정에 영향을 미칠 것으로 예상되나, 이에 대한 연구가 미미한 실정이다. 본 연구에서는 초음속 풍동 내부에서 발생하는 히스테리시스 현상을 수치해석으로 조사하였다. 비정상, 축대칭, 압축성 Navier-Stokes 방정식을 유한 체적법으로 이산화 하였으며, Spalart-Allmaras 난류모델을 적용하였다. 본 연구의 결과로 초음속 풍동 시동과정에서 시동압력비와 작동압력비가 다른 원인을 히스테리시스 현상으로 설명하였다.

• 전기학회논문지
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• 제56권1호
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• pp.112-116
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• 2007

We have investigated the hysteresis phenomenon of a hydrogenated amorphous silicon thin film transistor (a-Si:H TFT) and analyzed the effect of hysteresis phenomenon when a-Si:H TFT is a pixel element of active matrix organic light emitting diode (AMOLED). When a-Si:H TFT is addressed to different starting gate voltages, such as 10V and 5V, the measured transfer characteristics with 1uA at $V_{DS}$ = 10V shows that the gate voltage shift of 0.15V is occurred due to the different quantities of trapped charge. When the step gate-voltage in the transfer curve is decreased from 0.5V to 0.05V, the gate-voltage shift is decreased from 0.78V to 0.39V due to the change of charge do-trapping rate. The measured OLED current in the widely used 2-TFT pixel show that a gate-voltage of TFT in the previous frame can influence OLED current in the present frame by 35% due to the change of interface trap density induced by different starting gate voltages.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.871_872
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• 2009

This paper presents study of hysteresis model for magnetic hysteresis analysis by Preisach model. In ferromagnetic material, magnetization is non-linear and varies according to magnetic field which is called B-H curve. As hysteresis phenomenon affect on performance of motor, magnetic hysteresis analysis is essential and needed for designing motor that satisfies specification. Therefore, in this paper, methods for calculating magnetization are presented and discussed.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2011년도 제37회 추계학술대회논문집
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• pp.206-212
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• 2011

유체 시스템에서 히스테리시스 현상은 다양한 산업 및 공학의 응용 분야에서 발생하며, 주로 압력비의 시간변화 과정에서 발생한다. 초음속 노즐에서 충격파를 포함한 유동장은 이러한 히스테리시스 현상의 지배적인 영향을 받는다. 그러나 이와 관련된 유동의 물리적 현상에 대해서는 연구가 미비한 실정이다. 본 연구에서는 노즐구동압력비의 변화 과정 동안 초음속 노즐의 유동을 파악하기 위해 실험적 연구를 수행하였다. 순간 표면압력을 측정하기 위하여 다수의 압력변환기를 사용하였으며, 유동장의 가시화는 나노스파크 광원을 가지는 쉴리렌 가시화 장치를 이용하였다. 본 연구로부터, 히스테리시스 현상은 노즐의 기하학적 형상뿐만 아니라 압력비의 시간변화에 크게 의존하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 D
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• pp.2368-2370
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• 2000

In this paper, we proposed an inverse hysteresis model to cancel the nonlinear hysteresis phenomenon of a piezoelectric actuator and design a feedback control system based on the inverse hysteresis model. The piezoelectric actuator performs much better in open-loop response. However, the nonlinear hysteresis phenomenon should be linearized and the closed-loop control should be executed to get the required performance in the area, where high-speed and high-accuracy are required. Thus, it is shown by simulation that a good position tracking performance can be obtained for the repetitive desired position trajectory.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제34회 춘계학술대회논문집
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• pp.357-361
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• 2010

When high-pressure gas is exhausted through nozzle exit to the atmosphere, expanded supersonic jet is formed with the Mach disk at a specific condition. In two-dimensional supersonic jets, the hysteresis phenomenon of the reflected shock waves is found to occur under quasi-steady flow conditions. Transitional pressure ratio between the regular reflection and Mach reflection in the jet is affected by this phenomenon. In the present study, experiments are carried out on internal flow in a supersonic nozzle to clarify the hysteresis phenomena for the shock waves and to discuss its interdependence on the rate of the change of pressure ratio with time. Flow visualization is carried out separately on the straight and divergent channels downstream of the nozzle throat section. The influence that the hysteresis phenomena have on the location of shock wave in a supersonic nozzle is also investigated experimentally.

• 전력전자학회논문지
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• 제19권2호
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• pp.139-148
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• 2014

State-of-charge (SOC) is one of the significant indicators to estimate the driving range of the electric vehicle and to control the alternator of the conventional engine vehicles as well. Therefore its precise estimation is crucial not only for utilizing the energy effectively but also preventing critical situations happening to the power train and lengthening the lifetime of the battery. However, lead-acid battery is time-variant, highly nonlinear, and the hysteresis phenomenon causes large errors in estimation SOC of the battery especially under the frequent discharge/charge. This paper proposes a novel estimation technique for the SOC of the Lead-Acid battery by using a well-known Extended Kalman Filter (EKF) and an electrical equivalent circuit model of the Lead-Acid battery considering diffusion and hysteresis characteristics. The diffusion is considered by the reconstruction of the open circuit voltage decay depending on the rest time and the hysteresis effect is modeled by calculating the normalized integration of the charge throughput during the partial cycle. The validity of the proposed algorithm is verified through the experiments.

• 한국추진공학회지
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• 제16권2호
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• pp.58-64
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• 2012

유체 유동 시스템 내 히스테리시스 현상은 현재 다양한 산업 및 공학적인 응용분야에서 매우 빈번하게 발생되고 있으며, 이는 압력비 변화과정에서 주로 나타난다. 충격파를 포함한 초음속 노즐 유동장에서 히스테리시스 현상이 매우 발생하기 쉬우며, 이에 대한 물리적 유동특성에 대해서는 여전히 많이 알려지지 않았다. 본 연구에서는 노즐 압력비 변화에 따른 초음속 노즐내부 유동특성에 대해 조사하기 위해 실험적 연구를 수행하였다. 시간에 따른 노즐 벽압력 변화를 측정하기 위하여 다수의 압력변환기를 사용하였으며, 유동장의 가시화를 위해 나노스파크 쉴리렌 가시화 기법을 적용하였다. 연구 결과를 통해 히스테리시스 현상은 노즐의 기하학적 형상뿐만 아니라 시간에 따른 압력비 변화에 크게 의존함을 알았다.