• Journal of KSNVE
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• v.6 no.6
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• pp.791-800
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• 1996

Linear LQG controller has been investigated to control flexible link manipulators. The performance and complexity of these depend largely on the model upon which the controller is designed. In this study, the flexible modes of the link manipulator are considered to have uncertain parameters, which can be represented by random variable and these parameters are reflected on the weighting of performance. In this method, the exact modelling for the flexible modes is not necessary. The order of the resulting controller is much lower than the one based on a full model. Through numerical study, it is shown that the performance and the stability-robustness of the proposed controller reaches reasonably the one based on the full model.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10b
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• pp.599-606
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• 1992

A manipulator system that needs significantly large workspace volume and high payload capacity has greater link flexibility than typical industrial robots and teleoperators. If link flexibility is significant, position control of the manipulator's end-effector exhibits the nonminimum phase, noncollocated, and flexible structure system control problems. This paper addresses inverse dynamic trajectory planning issues of a flexible manipulator. The inverse dynamic equation of a flexible manipulator was solved in the time domain. By dividing the inverse system equation into the causal part and the anticausal part, the inverse dynamic method calculates the feedforward torque and the trajectories of all state variables that do not excite structural vibrations for a given end-point trajectory. Through simulation and experiment with a single-Unk flexible manipulator, the effectiveness of the inverse dynamic method has been demonstrated.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.379-384
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• 2005

Research interest on flexible body dynamics, has been increased recently. The major application areas are the auto-mobile, train, and heavy machinery. This paper attempted the dynamic analysis for the variable-gauge wheelset with a flexible body, to better understand the dynamic characteristics of the variable-gauge wheelset. In order to achieve this goal, a 3D-Virtual Mock-up model was built. The tendency of the stress and deformation for the flexible lever was investigated through component mode synthesis, contact mechanics and flexible body dynamics. This study is a pioneering work for the development of Korean type variable-gauge wheelset.

• Journal of KSNVE
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• v.6 no.2
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• pp.187-196
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• 1996

A new control strategy to actively control the vibration of a very flexible single link manipulator is proposed and experimentally realized. The control scheme consists of two actuators; a motor mounted at the beam hub and a piezoceramic bonded to the surface of the flexible link. The control torque of the motor to produce a desired angular motion is firstly determined by employing a sliding mode control theory on the equivalent rigid dynamics. The torque is then applied to the flexible manipulator in order to activate the commanded motion. During the motion, underirable oscillation is actively suppressed by applying a feedback control voltage to the piezoceramic actuator. Consequently, the desired tip position is favorably accomplished without vibration. Measured control responses are presented in order to demonstrate the efficiency of the proposed control methodology.

• Journal of Institute of Control, Robotics and Systems
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• v.4 no.6
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• pp.738-746
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• 1998

This paper presents a neural network-based adaptive controller for a single flexible-link. The control for feedback-error loaming of neural network is designed by using the re-definition approach. The neural network controllers are implemented on an single flexible-link experimental test-bed. The tip response is significantly improved and the vibrations of the flexible modes are damped very fast. Experimental and simulation results are presented of the proposed tip position tracking controllers over the conventional PD-type, passive controllers.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.9
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• pp.886-892
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• 2008

In this paper, a closed-loop observer to extract the center of mass (CoM) of a bipedal robot is suggested. Comparing with the simple conversion method of just using joint angle measurements, it enables to get more reliable estimates by fusing both joint angle measurements and F/T sensor outputs at ankle joints. First, a nonlinear-type observer is constructed to estimate the flexible rotational motion of the biped in the extended Kalman filter framework. It adopts the flexible inverted pendulum model which is appropriate to address the flexible motion of bipeds, specifically in the single support phase. The predicted estimates of CoM in terms of the flexible motion observer are combined with measurements (that is, output of the CoM conversion equation with joint angles). Then, we have final CoM estimates depending on the weighting values which penalize the flexible motion model and the CoM conversion equation. Simulation results show the effectiveness of the proposed algorithm.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.04b
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• pp.150-152
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• 2004

The number of layers in rigid PCB(printed circuit board) is restricted, so the number of components can be embedded in module is restricted also. But using flexible multilayer PCB, the layers over than 7 can be evaluated. In this study, to verify the possibility of application of flexible multilayer PCB to RF modules, multilayered embedded capacitor is fabricated and analyzed. The characteristics of embedded capacitor is analyzed and compared to that of MLCC and LTCC capacitor. Embedded capacitor has better electrical features than MLCC and compatible one to LTCC capacitor.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.65 no.2
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• pp.142-150
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• 2016

This paper developed new manufacture process technology of slim type flexible flat lighting product used lower power white LED. Flexible flat lighting is applied to letter sign lighting, traffic lighting, interior wall lighting, flat lighting, aquarium back lighting, wreath light etc. Main manufacture process technology were developed drawing software for electronics circuit, inkjet electronic circuit pattern and inkjet white ink coating. For pattern printing it was utilized for piezoelectonic inkjet head printing technology. Also high vacuum pressure laminating technology was waterproofing for LED flat lighting protection. Hence, form process technology we were manufactured for flexible flat lighting product of the power 12 W, input voltage 48 V and plane size $480{\times}480mm$. It acquired a these validity from experiment results.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.7 s.94
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• pp.1678-1685
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• 1993

This paper considers a time delay control of noncolocated flexible mechanical systems in discrete time domain. A stability criterion suggested in the previous paper is,extended in the consideration of infinite mode property of flexible systems and finite control sampling frequency. Based on the stability criterion, the one step advanced discrete time derivative control is suggested, which can stabilize infinite number of modes of a flexible system. The sensitivity analysis shows the robustness of the one step advanced control to the system parameter uncertainties and time delay errors. Application to a simply supported beam verifies the extended stability criterion and the effectiveness of the one step advanced D-control.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.499-504
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• 2000

Since large space structures(LSS) such as a space station, a solar power station satellite, etc., are theoretically distributed parameter and infinite-dimensional system, they have to be modeled into large finite-dimensional systems for control system design. Besides, there are fundamental problems in active vibration control of the large flexible structures. For example, a modeled large finite-dimensional system must be controlled with a much smaller dimensional controller. This causes the spillover phenomenon which degrades the control performances and reduces the stability margin. Furthermore, it may destabilize the entire feedback control system. In this paper, we proposed a novel control method for spillover suppression in the control of large flexible structures by using eigenstructure assignment. Its effectiveness in spillover suppression is investigated and verified by the numerical experiments using an example of the simply supported flexible beam which is modeled to have four controlled modes and eight uncontrolled modes.