• IE interfaces
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• v.7 no.3
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• pp.201-212
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• 1994

In this paper, we develop computerized procedures of the S-Curve, the cumulative progress rates of load input, applied to shipbuilding basic plan. For a real world ship yard, we study the application related problems and develop more efficient procedures of applying the curves in terms of usability and computerization. The yard currently do not have any mathematical expression for the S-Curve. They express the curves using data tables which represents data points of the manually drafted S-Curve graphs, which causes the difficulties in efficient computerization. Another problem the yard has is the lack of the feedback procedure of the actual load different from the initial plan. Due to those problems, the application procedures of the S-Curve require much time and endeavor amounting two full time employees. To resolve the problems, we develop the mathematical expression of the S-Curve using beta distribution function and the feedback procedure regenerating the planned load reflecting the difference between the initial plan and its realization. To build user friendly program, the graphic user interface is also developed using OSF/MOTIF toolkits. Through the development, we reduce the burden required in applying the curves to a part-time job of one employee.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.6
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• pp.1036-1041
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• 2008

Periodic disturbance is practically occurred in several engineering applications, especially in data storage systems. However, recently addressed controls for such problem were mostly dealt with its deterministic nature, which is rarely practical in real-time implementation. We present an adaptive control approach for DC motor systems with periodic stochastic disturbance whose frequency and magnitude are both random variables. We establish adaptive state feedback control which is linearly composed of nominal and corrective control parameter matrices. The former is derived from a nominal system model voiding disturbance and the latter is constructed from a disturbed system model by using Lyapunov stability theory. We carry out computer simulation to evaluate the proposed control methodology and compare to the recently addressed control method to demonstrate its superiority.

• Korean Journal of Computational Design and Engineering
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• v.15 no.2
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• pp.136-143
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• 2010

Realistic Modeling is to maximize the reality of the environment in which perception is made by virtual environment or remote control using two or more senses of human. Especially, the field of haptic rendering, which provides reality through interaction of visual and tactual sense in realistic model, has brought attention. Haptic rendering calculates the force caused by model deformation during interaction with a virtual model and returns it to the user. Deformable model in the haptic rendering has more complexity than a rigid body because the deformation is calculated inside as well as the outside the model. For this model, Gibson suggested the 3D ChainMail algorithm using volumetric data. However, in case of the deformable model with non-homogeneous materials, there were some discordances between visual and tactual sense information when calculating the force-feedback in real time. Therefore, we propose an algorithm for the Volume Haptic Rendering of non-homogeneous deformable object that reflects the force-feedback consistently in real time, depending on visual information (the amount of deformation), without any post-processing.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1692-1695
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• 1997

In this paper, a new control scheme for master-slave control of telerobot is proposed. The porposed method can be classified into unilater master-slave control methods in the aspect of the data flow. But the master arm in the proposed control scheme can deliver operator the similar kinesthetic sense as other bilateral force reflecting master arms do. The principle concept is that the sensed operator's force/torque is used as the reference input for a damping controller type of telerobot controller which track the operators efforts. Master arm and master controller can be implemented in a simple form, and it needs not be driven by actuators, but force sensing capability.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.236-239
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• 2003

In this paper, we investigate the issues for the design and implementation of tele-operation system based on the haptic interface. Here, the 3-DOF haptic device and the x-y-z stage are employed as master controller and slave system respectively. In this master-slave system, the force feedback algorithm, the modeling of virtual environments and the control method of x-y-z stage are proposed. In this paper, inernet network is used for data communication between master and slave. We construct virtual environment of the real convex surface from the force-feedback in controlling the X-Y-Z stage and getting the force applied by the 3-DOF haptic device.

• Journal of Welding and Joining
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• v.21 no.4
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• pp.80-86
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• 2003

Arc-spot welding is generally used in joining of precise parts such as case and core in electric compressor. It is important to control joining deformation in electric compressor because clearance control of micrometer order is needed for excellent airtightness and anti-nose. The countermeasures for this deformation in field have mainly been dependent on rule of try and error by operator's experience because of productivities. For control this deformation problem without influence on productivities, development of exact simulation model should be needed. In this study, on the basis of previous study, the analysis model io predict deformation of precise order in arc-spot welded structure with non-uniform stiffness is brought up through feedback and tuning between monitoring data and analysis results. For this, deformation monitoring system was built and boundary condition considering mechanical melting temperature was applied.

• Agricultural and Biosystems Engineering
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• v.1 no.1
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• pp.22-29
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• 2000

The development of bio-response feedback control system known as the speaking plant approach has been a challenging task for plant production engineers and scientists. In order to achieve the aim of developing such a bio-response feedback control system, the primary concern should be to develop a practical non-invasive technique for monitoring plant growth. Those who are skilled in raising plants can sense whether their plants are under adequate water conditions or not, for example, by merely observing minor color and tone changes before the plants wilt. Consequently, using machine vision, it may be possible to recognize changes in indices that describe plant conditions based on the appearance of growing plants. The interpretation of image information of plants may be based on image features extracted from the original pictorial image. In this study, the performance of a finite element retina was optimized by a genetic algorithm. The optimized finite element retina was evaluated based on the performance of neural plant growth monitor that requires input data given by the finite element retina.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.2
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• pp.124-130
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• 2003

The electro-hydraulic servo system with a servo valve is applied widely in force control. However, the composition of control system using a servo valve is difficult due to nonlinearities in the servo valve, such as square-root terms in flow equation. The electro-hydraulic servo system using a DDV(Direct Drive Valve) instead of a servo valve was proposed and it's characteristics was estimated. The DDV and whole system are modelled by parameter identification using the input-and-output data, then the models are verified by the comparison of simulation with experiment. Also, the state feedback controller has been designed based on this model, then the performance of the electro-hydraulic force servo system using a DDV is evaluated by simulation and experimental results.

• Journal of Electrical Engineering and Technology
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• v.8 no.6
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• pp.1389-1399
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• 2013

A discrete controller is designed for low power dc-dc switched mode power supplies. The approach is based on time domain and the control loop continuously and concurrently tunes the compensator parameters to meet the converter specifications. A digital state feedback control combined with the load estimator provides a complete compensation, which further improves the dynamic performance of the closed loop system. Simulation of digitally controlled Buck converter is performed with MATLAB/Simulink. Experimental results are given to demonstrate the effectiveness of the controller using LabVIEW with a data acquisition card (model DAQ Pad - 6009).

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.295-298
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• 1996

In this paper, a self-tuning optimal control algorithm is proposed to retain the optimal performance of an active suspension system, when the vehicle has some time varying parameters and parameter uncertainties. We consider a 2 DOF time-varying quarter car model which has the parameter variation of sprung mass, suspension spring constant and suspension damping constant. Instead of solving algebraic riccati equation on line, we propose a neural network approach as an alternative. The optimal feedback gains obtained from the off line computation, according to parameter variations, are used as the neural network training data. When the active suspension system is on, the parameters are identified by the recursive least square method and the trained neural network controller designer finds the proper optimal feedback gains. The simulation results are represented and discussed.