• 항공우주시스템공학회지
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• 제14권2호
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• pp.20-27
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• 2020

Several uncertainties in the landing environment of an aircraft are not considered, such as the falling speed, ambient temperature, and sensor noise. These uncertainties negatively affect the performance of the controller applied to a landing gear. The sliding mode control (SMC) method, which maintains the optimal performance of a controller under uncertainties, is used in this study. The landing gear is equipped with a magnetorheological damper that changes the yield shear stress according to the applied magnetic field. The applied controller employs a hybrid control combining Skyhook control and force control. The SMC maintains the optimal performance of the hybrid control by minimizing the tracking error of the damper force, even in various landing environments where parameter uncertainties are applied. The effect of SMC is verified through co-simulation results from Simscape and Simulink.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 추계학술대회 논문집
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• pp.331-336
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• 2012

This paper proposes a new type of high-frequency directional valve controlled by the piezostack actuator associated with displacement amplifier. As a first step, a dynamic model of directional valve which can operate at 200 Hz with a flow rate of 12 l/min is derived by considering pressure drop and flow force. As a second step, an appropriate piezostack is selected by considering actuation force as well as field-dependent displacement. Subsequently, in order to control spool displacement and flow rate a proportional-derivative (PD) controller is designed based on the $3^{rd}$-order valve system. Control performances such as sinusoidal trajectory tracking of the spool displacement in time domain are evaluated. In addition, the field-dependent flow rate is also presented to verify the required performance of the valve system.

• 정보저장시스템학회:학술대회논문집
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• 정보저장시스템학회 2005년도 추계학술대회 논문집
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• pp.229-234
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• 2005

A novel method to measure the interaction movement, focusing direction and tracking direction in an optical pick-up, is proposed and the decoupling control for it is discussed. First, the basic principle of the coupline analysis method using back electromotive farce is introduced. Second, the interaction analysis between focusing direction and tracking direction fur commercial slim type actuator is performed using the proposed method. Finally, the coupling analysis and decoupling control for the slim type optical pick-up are discussed. From the brief simulation, we shows that the effectiveness and validity of the proposed method.

• 한국소음진동공학회논문집
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• 제22권10호
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• pp.1020-1026
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• 2012

This paper proposes a new type of high-frequency directional valve controlled by the piezostack actuator associated with displacement amplifier. As a first step, a dynamic model of directional valve which can operate at 200 Hz with a flow rate of 12 litter/min is derived by considering pressure drop and flow force. As a second step, an appropriate piezostack is selected by considering actuation force as well as field-dependent displacement. Subsequently, in order to control spool displacement and flow rate a proportional-derivative(PD) controller is designed based on the 3rd-order valve system. Control performances such as sinusoidal trajectory tracking of the spool displacement in time domain are evaluated. In addition, the field-dependent flow rate is also presented to verify the required performance of the valve system.

• International Journal of Computer Science & Network Security
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• 제21권5호
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• pp.31-34
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• 2021

The article considers the possibilities of increasing the accuracy of estimates of the parameters of the trajectory of the target with the provision of a given probability of stable support of the air object, in particular, during its maneuver. The aim of the work is to develop a filtration algorithm that provides a given probability of stable tracking of the air object by determining the regular components of filtration errors, in particular, when maneuvering the air object, and their compensation with appropriate correction of filter parameters and estimates of air object trajectory parameters.

• 한국정보통신학회논문지
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• 제26권12호
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• pp.1816-1825
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• 2022

본 논문에서는 다양한 해상도의 카메라를 사용하는 감시 카메라 네트워크에서 각 사람을 추적하는 새로운 접근 방식을 제안한다. 다수의 비겹침 카메라 상에서 사람 추적 시 기존에 사용되던 사람 특징 정보는 다양한 카메라 시야 조건에 쉽게 영향을 받는다. 이러한 한계를 극복하기 위해 제안하는 시스템은 외모 정보와 함께 얼굴 정보를 활용한다. 일반적으로 감시 카메라로 촬영하는 사람 영상은 해상도가 낮은 경우가 많기 때문에 추적을 용이하게 하기 위해 저해상도 얼굴에서도 유용한 특징을 추출할 수 있어야 한다. 제안하는 추적 방식에서 사람 얼굴 특징을 추출하기 위해 탐지된 얼굴을 정면화한 후 텍스쳐 기반의 특징을 추출한다. 또한 감시 카메라에 포착된 얼굴의 크기가 매우 작은 경우 얼굴을 확대하는 초해상도 기법도 함께 활용한다. 공개된 데이터셋인 Dana36을 이용하여 수행한 실험결과를 통해 제안된 알고리즘의 우수한 성능을 보여준다.

• 한국정보통신학회논문지
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• 제21권2호
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• pp.416-422
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• 2017

인간과 로봇이 같은 공간에서 작업을 할 경우가 많아짐에 따라 안전성을 고려한 로봇의 제어가 필요하다. 안정성을 위해서 로봇은 인간의 힘에 순응해야 함으로 낮은 임피던스가 요구되는 반면에 높은 제어성능을 갖도록 하기 위해서는 외란에 강인하기 위해서는 높은 임피던스가 요구된다. 이러한 이율배반적인 목적을 달성하기 위해서 본 연구에서는 적분슬라이딩모드와 외란관측기(DOB)를 사용하여 인간의 힘 이외의 외란에는 강인한 특성을 보이고 인간의 힘에는 순응할 수 있는 제어기를 설계한다. 인간의 동작이 특정 주파수의 범위에 있다는 사실에 근거하여 인간에 의한 외란인 경우의 외란에 대해서는 로봇이 순응하도록 슬라이딩모드를 설계하는 것이 본 논문의 독창적인 아이디어이다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.63-67
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• 2004

The problem is improving the positioning precision of a permanent magnet linear synchronous motor (PMLSM). Thus, this paper presents the design and realization of an adaptive dither to reduce the force ripple in PMLSM. A composite control structure is used, consisting of three components: a simple feed-forward component, a PID feedback component and an adaptive feed-forward compensator (AFC). Especially adaptive feed-forward component cancel out detent force using wavelet transformation. Computer simulation results verify the effectiveness of the proposed scheme for high precision motion trajectory tracking using the PMLSM

• 제어로봇시스템학회논문지
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• 제17권7호
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• pp.641-646
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• 2011

A low cost gait analysis system, which can measure stride length, walking speed, and ground reaction force, is proposed. A gait analysis system is used for medical evaluation of patients and rehabilitation assistance. Low cost cameras are attached to a shoe and movement of a shoe is estimated using infrared LED landmarks. Ground reaction force is measured from pressure sensors, which are installed inside a shoe. Through experiments, it is shown that the proposed system can be used to obtain stride length, walking speed, and ground reaction force.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년 학술대회 논문집 정보 및 제어부문
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• pp.333-335
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• 2006

This paper presents a force-reflecting teleoperation scheme with time delay. In reciprocal systems, to improve the stability and performance of the tleleoperation system, the network provides a wide bandwidth, no congestion. However, as use of Internet increases, congestion situation of network increased and transmission time and packet loss increased accordingly. This can make system unstable at remote control. In this paper, we present a passive control scheme for a force reflecting bilateral teleoperation system via the Internet and we investigated how a varying time delay affects the stability of a teleoperation system. A new approach based on a passive control scheme was designed for the system. The simulation results and the tracking performance of the implemented system are presented in this paper.