• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.5
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• pp.1133-1138
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• 2012

In the paper, design of nonlinear sliding surfaces which are based on optimal control is studied, The state trajectory by the input of optimal control was obtained by Frobenius theorem and matrix decomposition method, was set the nonlinear sliding surfaces of the system. The states is maintained to sliding surfaces from initial states. As the result, robustness of the system can be guaranteed throughout an entire response of the system starting form the initial time instance, the uncertainty and external disturbance that can occur during the reaching time is removed, the problem of large control input was solved, and setting the sliding surfaces optimal path was able to reduce the tracking time. The validity of the proposed control scheme is shown in computer simulation for inverted pendulum.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.588-593
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• 2011

In this study, the performance analysis method for ramjet engine system with atmospheric air disturbance was proposed. Flight path was determined to satisfy dynamic pressure constant at each flight altitude. The atmospheric air disturbance incoming into a engine intake was simulated by the model Tank proposed. The performance parameters was investigated at each flight condition with air disturbance. Engine operation stability was evaluated as analysis of the normal shock position.

• Journal of Drive and Control
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• v.13 no.3
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• pp.15-23
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• 2016

The direct-drive servo valve(DDV) is a kind of one-stage valve because the main spool valve is directly driven by the dc motor. Since the DDV structure is simple, it is less expensive, more reliable, and offers a reduced internal leakage and a reduced sensitivity to fluid contamination. The control system of the DDV is highly nonlinear due to a current limiter, a voltage limiter, and the flow-force effect on the spool motion. The shape of the step response of the DDV-control system varies considerably according to the magnitudes of the step input and the load pressure. The system-design requirements mean that the overshoots should be less than 20%, and the errors at 0.02s should be less than 2%, regardless of the reference-step input sizes of 1V and 5V and the load-pressure magnitudes of 0MPa and 20.7MPa. To satisfy the system-design requirements, the PID-controller parameters of $K_c$, $T_i$ and $T_d$, and the derivative-feedback gain of $K_{der}$ are designed using the root locus and manual tuning.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.4
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• pp.906-912
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• 2014

The study of fish robot is a main subject that are related with the propulsive force comparison using a varying amplitude and frequency for body and tail motion trajectory, and the quick turn using a proper trajectory function. In this study, when a fish robot thrusts forward, feedback control is difficult to apply for a fish robot, because body and tail joints as a sine wave are rolled. Therefore, we detect the virtual position based on the path of the fish robot, define the angle errors using the detected position and the look-ahead point on the given path, and design a controller to track given path. We have found that the proposed method is useful through the computer simulations.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.5
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• pp.41-47
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• 2002

In this paper, a guidance law applicable to aircraft automatic landing is proposed and its performance is compared with the conventional ILS-type landing approach. The concept of miss distance, which is commonly used in the missile guidance laws, and Lyapunov stability are effectively combined to obtain the landing guidance law. The new landing guidance law is integrated into the existing controller and is applied to the landing approach and flare phases of landing procedure. Numerical simulation results show that the new landing guidance law is a viable alternative to the conventional strategies that directly control the longitudinal deviation or altitude.

• 한국공간정보시스템학회:학술대회논문집
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• 2004.12a
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• pp.91-97
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• 2004

GPS 및 무선 통신 기술의 발달과 무선기기의 소형화, 고속 네트워크 구축 등에 힘입어 휴대전화 사용 고객이나 차량의 위치 추적이 용이해지고 있다. 이로 인해 차량 및 고객이 변화하는 위치에 따라 적절한 서비스를 제공하는 위치 기반 서비스가 활발히 연구되고 있으며, 원활한 교통 소통 및 물류 수송을 위해 차량의 위치 정보를 적절히 활용, 관리하는 차량 추적 및 관리 시스템이 개발되고 있다. 그러나 개발된 차량 관리 시스템들은 각 시스템마다 서로 다른 차량 위치 데이터 저장 구조 및 질의 처리 방식과 색인 기법 등을 활용하기 때문에, 시스템간의 호환 및 정보 교환 등에 어려움을 갖고 있다. 따라서 이 논문에서는 차량 관리 시스템간의 정보 교환 및 차량의 위치 및 궤적 데이터의 효과적인 질의를 지원하기 위한 이동 객체질의어를 설계하고, 이를 지원하는 차량 관리 시스템을 구현한다. 제시된 이동 객체 질의어는 SQL를 기반으로 물류 관리 시스템에서 특정 구간 사이의 궤적, 특정 지점에서의 출발 렌 도착 시간 및 불확실한 위치 추정 등과 같은 차량의 이동에 대한 정보를 얻기 위해 지원된다. 그리고, 물류 차량 관리를 포함한 다양한 이동 객체 관리 시스템에서 이러한 이동 객체 질의어와 같은 어떤 표준화된 질의어를 지원할 경우, 서로 간의 정보 활용에 많은 도움을 줄 수 있다.

• Korean Journal of Optics and Photonics
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• v.12 no.4
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• pp.281-288
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• 2001

In this study we carried out athermalization analysis and tests to meet the required optical performance for thennal imaging systems even if the systems were operating over a wide temperature range. By using optical design programs such as Code- V and SIGMA2100, the simulation for athermalization was done with FPA thermal imaging system. In the athermalization test putting the thermal imaging system and collimator into a temperature chamber, the images depending on the temperature were recorded on video tape. In particular, the zoom thermal imaging system with two dimensional array detector was tested to check the result of the athermalization simulation. As a result, it was proved to meet the required optical performance for the thermal imaging system within $-32-+50^{\circ}C$ temperature range. range.

• Journal of IKEEE
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• v.9 no.1 s.16
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• pp.47-56
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• 2005

A new improved robust variable structure tracking controller is presented to provide an accurately prescribed tracking performance for brushless direct drive(BLDD) servo motors(SM) under uncertainties and load variations. A special integral sliding surface suggested for removing the reaching phase problems can define its ideal sliding mode and virtual ideal sliding trajectory from an initial position of SM. The tracking error caused by the nonzero value of the sliding surface is derived. A corresponding continuous control input with the disturbance observer is suggested to track a predetermined virtual ideal sliding trajectory within a prescribed value under all the uncertainties and load variations. The usefulness of the proposed algorithm is demonstrated through the comparative simulations for a BLDD SM under load variations.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.8
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• pp.1759-1766
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• 2003

This paper proposes a neuro­fuzzy controllers for trajectory tracking control of robot manipulators. The computed torque method is an effective means for trajectory tracking control. However, the tracking performance of this method is severely affected by the uncertainties of robot manipulators. Therefore, the proposed controller is used to compensate the uncertainties of robot manipulators. In the neuro­fuzzy controllers, the number of fuzzy rules used forty­nine. The effectiveness of the proposed controllers is demonstrated by computer simulations using two­link robot manipulator, As a result, it is confirmed that the output of the proposed neuro­fuzzy controllers can efficiently decrease the uncertainties of robot manipulator.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.6
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• pp.1574-1580
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• 2008

In this paper, to bring under robust and accurate control of auto-equipment systems which disturbance, parameter alteration of system, uncertainty and so forth exist, neural network controller called dynamic neural processor(DNP) is designed In order to perform a elaborate task like as assembly, manufacturing and so forth of components, tracking control on the trajectory of power coming in contact with a target as well as tracking control on the movement course trajectory of end-effector is indispensable. Also, the learning architecture to compute inverse kinematic coordinates transformations in the Plants of auto-equipment systems is developed and the example that DNP can be used is explained. The architecture and learning algorithm of the proposed dynamic neural network, the DNP, are described and computer simulations are provided to demonstrate the effectiveness of the proposed learning method using the DNP.