• 제어로봇시스템학회논문지
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• 제16권3호
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• pp.249-255
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• 2010

The paper proposes a new type of robust speed control strategy for permanent magnet synchronous motor by using PD-sliding mode hybrid control. The PD control has a good performance in the transient region while the sliding mode controller provides the robustness against system uncertainties. Taking advantages of the two control strategies, the proposed control method utilizes the PD control in the approaching region to the sliding surface and the sliding mode control near at the sliding surfaces. The chattering problem of the sliding mode controller is eliminated by applying the saturation function for the switching function of the sliding mode control. The stability of the sliding mode control is verified by using Lyapunov function with the proper selection of variable gains. It is shown that with this simple switching algorithm, stability of the overall hybrid control system is ensured. Through the simulations, the PD-sliding mode algorithm is shown to have a good performance in the transient response as well as being robust against disturbances. The robustness of the PD-sliding mode algorithm is further demonstrated against various external disturbances in the real experiments of SPMSM motor control.

• 제어로봇시스템학회논문지
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• 제8권2호
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• pp.89-96
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• 2002

A new chattering free PD-sliding mode hybrid control scheme is proposed for robot manipulators. This hybrid controller is composed of a PD controller and a semi-continuous sliding mode controller. It has a good robust performance in reaching mode which does not possess invariance property of sliding mode, and has chattering free characteristics in sliding mode. Thus, the PD-sliding mode hybrid controller has a good robust performance in the whole region. It is shown that the proposed control has a good transient response and trajectory tracking performance for a 2-link SCARA robot manipulator.

• 제어로봇시스템학회논문지
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• 제14권12호
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• pp.1286-1293
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• 2008

This paper proposes a realization of robust trajectory tracking for an industrial robot by using PD-sliding mode hybrid control. The PD control has a good performance in the transient period while the sliding mode control has robustness against the system uncertainties. The proposed control method is proposed for the control of a multi-joint robot by taking advantages of both the PD and sliding mode controls. The embodiment of distributed controllers that drive 4-DOF axes has evaluated through experiments with the multi-joint robot AT1. The PD-sliding mode algorithm which is proposed in this paper shows a good performance in the transient period and robustness against disturbances and This paper shows accuracy of end-effector.

• 한국전기전자재료학회논문지
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• 제23권5호
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• pp.383-387
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• 2010

The response characteristics of AE (acoustic emission) sensors with a coupled vibration mode and a non-coupled vibration mode were investigated according to PD(partial discharge) quantities in XLPE (cross linked polyethylene) sheets and craft papers immersed in insulating oil. The response voltages of a coupled vibration mode AE sensor were linearly proportional to the PD quantities up to 1,000 pC in XLPE sheets, while a non-coupled vibration mode AE sensor did not show the similar linearity. In case of a test of craft papers immersed in insulating oil, a linearity between response voltages and PD quantities was observed up to 550 pC, but after that, similar linearity between response voltage of any types of AE sensor and PD quantities was not shown.

• 대한방사선기술학회지:방사선기술과학
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• 제40권2호
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• pp.213-218
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• 2017

최근 고위험 임신군이 증가함에 따라 과거에 비해 음향파워 세기가 높은 도플러초음파 이용이 산전 진단에서 점차 증가하고 있으며, 여러 기관에서 가이드라인을 설정하여 과도한 노출을 자제하고 있다. 따라서 본 연구에서는 장시간 초음파검사 실시에 따른 검사모드 별 체표면의 온도변화를 알아보고 열효과에 영향을 받지 않는 노출시간을 고찰해 보고자 하였다. 시간경과에 따른 B mode, C mode, PD mode 별 초음파를 조사한 부위와 조사하지 않은 부위의 온도변화를 측정하여 차이를 비교하였으며 B mode는 초음파 조사 후 10분, 50분에서, C mode는 20분부터, PD mode는 30분부터 온도변화에 유의한 차이를 나타내었다(p<0.01). 측정시점에 따라 3개의 mode에서 모두 온도상승에 차이를 보였으며(p<0.000), PD mode가 가장 온도변화에 민감한 반응을 나타내었다. 또한 초음파 노출시간이 증가함에 따라 온도상승 시간이 짧아짐을 알 수 있었다. 따라서 배아나 태아를 관찰하기 위한 초음파검사 시 과도한 검사시간을 피하여 진단목적으로만 신속하게 사용할 것을 권고한다.

• International Journal of Control, Automation, and Systems
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• 제4권5호
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• pp.545-558
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• 2006

In this paper, PD-like visual servoing is modified in two ways: a sliding-mode observer is applied to estimate the joint velocities, and a RBF neural network is used to compensate the unknown gravity and friction. Based on Lyapunov method and input--to-state stability theory, we prove that PD-like visual servoing with the sliding mode observer and the neuro compensator is robust stable when the gain of the PD controller is bigger than the upper bounds of the uncertainties. Several simulations are presented to support the theory results.

• 한국광학회지
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• 제18권6호
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• pp.389-394
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• 2007

단일모드 광섬유를 이용한 수소센서의 특성을 이론 및 실험으로 분석하였다. 검출 소재로 팔라듐(Pd:palladium) 필름을 이용하였고 광섬유와 Pd 사이의 접착력을 강화하기 위해 니켈(Ni) 필름을 사용하였다. 제작된 센서의 반응감도와 반응시간은 팔라듐 박막의 두께에 크게 의존하였다. 단일모드 광섬유 끝단에 접착층으로 5 nm 두께의 Ni 박막과 감응막으로 10 nm 두께의 Pd가 코팅된 센서는 0.6 dB의 반사도의 변화와 $3{\sim}5$초의 반응시간을 보였다.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2003년도 학술대회논문집
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• pp.103-105
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• 2003

The principle of the ultra-high frequency (UHF) method to detect partial discharge(PD) in GIS is to measure the UHF electromagnetic waves excited by PD pulses. Such electromagnetic waves propagate along the GIS busbar in the TEM-mode, TE-mode, TM-mode. And the coaxial busbar of the GIS acts as a waveguide in which the UHF electromagnetic waves travel. This paper was studied the analysis on damping characteristic of electromagnetic waves excited by PD in GIS and presented the method to yield the cutoff frequency for determine the minimum band of sensor that detect the PD pulse.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2006년 창립20주년기념 정기학술대회 및 국제워크샵
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• pp.351-354
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• 2006

In underwater environment, the control of AUV is difficult, because of the existence of parameter uncertainties and disturbances as well as highly nonlinear and coupled system dynamics. The requirement for the simple and robust controller which works satisfactorily in those dynamical uncertainties, call for a design using the PD or sliding mode controller. The PD controller is very popular controller in the industrial field and the sliding mode controller has been used successfully for the AUV controller design. In this paper, the two controllers arc designed for ISiMI(Integrated Submergible Intelligent Mission Implementation) AUV and the performances are compared by numerical simulation under the modeling uncertainty and disturbances. The design process of PD and sliding mode controller for ISiMI AUV and simulation results are included to compare the performances of the two controllers.

• 대한전자공학회논문지
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• 제10권6호
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• pp.56-61
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• 1973

압전 결정 LiNbO3에서 탄성표면파(Rayleigh 표면파)의 온도계수가 가장 작은 131° 로테이트 Y캇트의 전반로에 Ag와 Pd를 증착하여 증착막의 두께에 따른 위상속도의 변화와 위상속도의 온도계수의 변화를 수치해석방법에 의하여 계산하였다. 계산한 결과 Ag의 경우는 증착막의 두께가 증가함에 따라 온도계수가 급격히 증가하나 Pd의 경우는 증가와 감소의 불규칙성을 보이며 wh=9000에서 -36×10 /℃의 위상속도의 온도계수의 최소치를 얻었다.