• Journal of KSNVE
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• v.6 no.1
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• pp.35-44
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• 1996

This paper presents a new type of fuzzy-sliding mode controller for robust tip position control of a single-link flexible manipulator subjected to parameter variations. A sliding mode controller is formulated with an assumption that imposed parameter variations are bounded so that certain deterministic performance can be guaranted. In the design of the sliding mode controller, so called moving sliding surface is adopted to minimize the reaching phase and thus mitigate system sensitivity to the variations. The sliding mode controller is then incorporated with a fuzzy technique to reduce inherently ever-existing chattering which is impediment in position control of flexible manipulators. A set of fuzzy parameters and control rules are obtained from a relation between predetermined sliding surface and representative points in the state space. Computer simulations are undertaken in order to demonstrate superior control performance of the proposed methodology.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.1030-1033
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• 2005

Today's most equipments that contain embedded system only support simple menus and background graphics. However, as the embedded system is applied for much more various fields and the user's needs for graphical interface become higher, the support for multimedia and moving pictures became an important criterion to evaluate the performance of a equipment. Because the present embedded system uses software to construct display environment, it is difficult to meet the bandwidth for multimedia contents and moving pictures. Using software for graphic also lowers the performance of the main function by overloading the processor. In this paper, we present an OLED/TFT-LCD controller suitable for embedded systems. The architecture we propose is described in HDL and the performance is evaluated in comparison with the existing embedded systems.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.6
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• pp.773-781
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• 2018

In recent years, a study of power-line inspection using an unmanned aerial vehicle (UAV) has been actively conducted. However, relevant studies have been conducting power-line inspection with an UAV operated by manual control, and they have developed just power-line detection algorithm on aerial images. To overcome limitations of existing research, we propose a drone-based power-line tracking system in this paper. The main contributions of this paper are to operate developed system under configured environment and to develop a power-line detection algorithm in real-time. Developed system is composed of the power-line detection and the image-based tracking control. To detect a power-line in real-time, a region of interest (ROI) image is extracted. Furthermore, clustering algorithm is used in order to discriminate the power-line from background. Finally, the power-line is detected by using the Hough transform, and a center position and a tilt angle are estimated by using the Kalman filter to control a drone smoothly. We design a position controller and an attitude controller for image-based tracking control, and both controllers are designed based on the proportional-derivative (PD) control method. The interaction between the position controller and the attitude controller makes the drone track the power-line. Several experiments were carried out in environments where conditions are similar to actual environments, which demonstrates the superiority of the developed system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.11
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• pp.2534-2539
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• 2015

Method for regulating voltage using a generator voltage regulating device (AVR) is divided in an existing analog system and a digital replacement. Typically, to adjust the voltage by using a brushless excitation system of the type to be reduced for a voltage change under all. The control method of the AVR as a PID (proportional-integral-differential) control method is widely used. However, the control scheme is to reduce the transient response of the control parameters of the controller to the control object. Therefore, if the control target should change, there is a problem, reset the parameters of the controller again. In this study, without having to reset the parameters of the controller for the parameter variations to be controlled iPID (intelligent PID) using a controller designed to obtain a generator AVR system voltage variation is small in response to full load is applied to and through simulations and experiments improved transient response.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.8
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• pp.930-935
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• 2019

Our proposed system, MobiAutoBot, is a conceptual model of robotics process automation software at a cognitive automation level that can support mobile devices. MobiAutoBot consists of two parts: MobiAutoBot controller and MobiAutoBot runner. The MobiAutoBot controller directs, monitors, and interacts the Job on the mobile device, and the MobiAutoBot runner installed on the mobile device performs the commanded operation. If we provide automation for mobile devices to small businesses through our proposed MobiAutoBot, we can build low-cost robotic process automation functions that can be linked to existing information systems with mobile devices such as simple smartphones, even without an expensive information-based infrastructure. Our proposal is expected to serve as an opportunity to spread automation of robotics processes even to small and medium-sized companies and individual users who are difficult to equip with all information system infrastructure.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.12
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• pp.5723-5743
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• 2018

The evolving internet-based services demand high-speed data transmission in conjunction with scalability. The next generation optical network has to exploit artificial intelligence and cognitive techniques to cope with the emerging requirements. This work proposes a novel way to solve the dynamic provisioning problem in optical network. The provisioning in optical network involves the computation of routes and the reservation of wavelenghs (Routing and Wavelength assignment-RWA). This is an extensively studied multi-objective optimization problem and its complexity is known to be NP-Complete. As the exact algorithms incurs more running time, the heuristic based approaches have been widely preferred to solve this problem. Recently the software-defined networking has impacted the way the optical pipes are configured and monitored. This work proposes the dynamic selection of path computation algorithms in response to the changing service requirements and network scenarios. A software-defined controller mechanism with a novel packet matching feature was proposed to dynamically match the traffic demands with the appropriate algorithm. A software-defined controller with Path Computation Element-PCE was created in the ONOS tool. A simulation study was performed with the case study of dynamic path establishment in ONOS-Open Network Operating System based software defined controller environment. A java based NOX controller was configured with a parent path computation element. The child path computation elements were configured with different path computation algorithms under the control of the parent path computation element. The use case of dynamic bulk path creation was considered. The algorithm selection method is compared with the existing single algorithm based method and the results are analyzed.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.6
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• pp.659-665
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• 2023

The exciter of a ship generator adjusts the magnetic flux through excitation current control to maintain the output terminal voltage constant. The voltage controller inside the exciter typically uses a proportional integral control method. however, the response characteristics determined by the gain and time constant produce unwanted output owing to an inappropriate setting value that can reduce the quality and stability of power within the ship. In this study, a neural network circuit is learned using stable input/output data that can be obtained through the AC4A type exciter model provided by IEEE, and the simulation is performed by replacing the existing proportional integral control type voltage controller with the learned neural network circuit controller. Consequently, overshooting was improved by up to 9.63% compared with that of the previous model, and excellence in stable response characteristics was confirmed.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.272-275
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• 1997

When a manipulator makes contact with an object having position uncertainty, performance measures vary considerably with the control law. To achieve the optimal solution for this problem, an unique objective function that weights time and impact force is suggested and is solved with the help of variational calculus. The resulting optimal velocity profile is then modified to define a sliding mode for the impact and force control. The sliding mode control technique is used to achieve the desired performance. Sets of experiments are performed, which show superior performance compared to any existing controller.

• International Journal of Control, Automation, and Systems
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• v.5 no.6
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• pp.712-717
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• 2007

This paper is concerned with the problem of state feedback control of continuous-time nonlinear Markovian jump systems, which are represented by Takagi-Sugeno fuzzy models. A new method for designing state feedback stabilizing controllers is presented in terms of solvability of a set of linear matrix inequalities (LMIs), and it is shown that the new design method provides better or at least the same results of the existing method in the literature. Finally, a numerical example is given to illustrate the effectiveness of the proposed method.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10a
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• pp.801-806
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• 1987

The receding horizon tracking control for the discrete time invariant systems is presented in this paper. This control law is derived with the receding horizon concept from the standard tracking problems. Stability properties of this control law are analyzed. It is shown that there exists a finite horizon index for which the closed loop systems are always asymptotically stable. The receding horizon tracking control is a kind of predictive control and will add a new clan to many existing predictive controls, with which some comparisons are made.