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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Institute of Control, Robotics and Systems
Journal Basic Information
Journal DOI :
Institute of Control, Robotics and Systems
Editor in Chief :
Volume & Issues
Volume 14, Issue 12 - Dec 2008
Volume 14, Issue 11 - Nov 2008
Volume 14, Issue 10 - Oct 2008
Volume 14, Issue 9 - Sep 2008
Volume 14, Issue 8 - Aug 2008
Volume 14, Issue 7 - Jul 2008
Volume 14, Issue 6 - Jun 2008
Volume 14, Issue 5 - May 2008
Volume 14, Issue 4 - Apr 2008
Volume 14, Issue 3 - Mar 2008
Volume 14, Issue 2 - Feb 2008
Volume 14, Issue 1 - Jan 2008
Selecting the target year
Dependence of Blue Organic Emitter Layer Thickness to Optical Property of 2-wavelength White Organic Light-emitting Diodes
Park, Chan-Jun ; Cho, Nam-Ihn ; Song, Young-Wook ;
Journal of Institute of Control, Robotics and Systems, volume 14, issue 6, 2008, Pages 511~514
DOI : 10.5302/J.ICROS.2008.14.6.511
2-wavelength type white OLED devices have been made consisted of two layers; a layer with blue light emitting DPVBi host and other EML layer with yellow emitting rubrene dopant. New method to get white emitting device has been suggested by varying thicknesses of the DPVBi layer. The ITO/2-TNATA(
) structure has showed optimum results in CIE coordinates of (0.3233, 0.33). OLED devices with this structure has properties of
at turn-on voltage of 3.9V and
at 7.9V. This structure has advantages of simple fabrication and easy to emit the white color.
Selection of Heater Location in Linear Source for OLED Vapor Deposition
Joo, Young-Cheol ; Han, Choong-Hwan ; Um, Tai-Joon ; Lee, Sang-Wook ; Kim, Kug-Weon ; Kwon, Kye-Si ;
Journal of Institute of Control, Robotics and Systems, volume 14, issue 6, 2008, Pages 515~518
DOI : 10.5302/J.ICROS.2008.14.6.515
Organic light emitting diode(OLED) is one of the most promising type of future flat panel display. A linear source is used to deposite organic vapor to a large size OLED substrate. An electric heater which is attached on the side of linear source heats the organic powder for the sublimation. The nozzle of heater, which is attached at the top of the linear source has an optimal temperature. An numerical analysis has been performed to find optimal heater position for the optimal nozzle temperature. A commercial CFD program, FLUENT, is used on the analysis. Two-dimensional and three-dimensional analysis have been performed. The analysis showed that the heater should be attached at the outer side of crucible wall rather than inner side of housing, which was original design. Eighteen milimeter from the top of the linear source was suggested as the optimal position of heater. Improving thermal performance of linear source not only helps the uniformity of organic vapor deposition on the substrate but also increase productibity of vapor deposition process.
Development of Elimination Method of Measurement noise to Improve accuracy for White Light Interferometry
Ko, Kuk-Won ; Cho, Soo-Yong ; Kim, Min-Young ;
Journal of Institute of Control, Robotics and Systems, volume 14, issue 6, 2008, Pages 519~522
DOI : 10.5302/J.ICROS.2008.14.6.519
As industry of a semiconductor and LCD industry have been rapidly growing, precision technologies of machining such as etching and 3D measurement are required. Stylus has been important measuring method in traditional manufacturing process. However, its disadvantages are low measuring speed and damage possibility at contacting point. To overcome mentioned disadvantage, non-contacting measurement method is needed such as PMP(Phase Measuring Profilometry), WSI(white scanning interferometer) and Confocal Profilometry. Among above 3 well-known methods, WSI started to be applied to FPD(flat panel display) manufacturing process. Even though it overcomes 21t ambiguity of PMP method and can measure objects which has specular surface, the measuring speed and vibration coming from manufacturing machine are one of main issue to apply full automatic total inspection. In this study, We develop high speed WSI system and algorithm to reduce unknown noise. The developing WSI and algorithm are implemented to measure 3D surface of wafer. Experimental results revealed that the proposed system and algorithm are able to measure 3D surface profile of wafer with a good precision and high speed.
A Design and Implementation of a Mobile Test Device Based-on Embedded System
Kim, Hong-Kyu ; Lee, Ki-Wha ; Moon, Seung-Jin ;
Journal of Institute of Control, Robotics and Systems, volume 14, issue 6, 2008, Pages 523~529
DOI : 10.5302/J.ICROS.2008.14.6.523
In this paper, we proposed mobile LCD module test device on embedded based, when operating the existing LCD, divide flicker clearly in full frame, and configuration so as to support between other CPU interface, MDDI, SPI, 24Bit RGB interface, etc. that is based on a high-speed CPU. In addition, when demand to test about each pixel of LCD, it is possible to change IP design of H/W, FPGA, but proposed system is application possible without other design changing. Proposed system is made smaller and equipped with battery, so secure with mobility for effective test the LCD/OLED module and it is able to test the pattern by the client program, for example exiting picture, mpeg, simple pattern test and test per pixel, scale, rotation, Odd/Even pixel per video, etc. From now on, if integrating with independent test system and it is configured that is able to mutual communication and test, it is expected to reduce consumption of human resources and improve productivity for LCD module test.
Optical Characteristics of the LGP with Nanometer-patterned Sizes on Its Both Surfaces
Hong, Chin-Soo ; Kim, Chang-Kyo ; Lee, Byoung-Wook ; Kim, Kyoung-Rae ;
Journal of Institute of Control, Robotics and Systems, volume 14, issue 6, 2008, Pages 530~534
DOI : 10.5302/J.ICROS.2008.14.6.530
The LGP with nanometer structures resulted in enhancement of optical efficiency. Its fundamental mechanism is to recycle the polarized light via one round-trip through QWP(Quarter-wave Plate) but the maximum efficiency to reach with this method is limited up to 2. To get the larger efficiency than this a LGP with 1D PC(one-dimensional photonic crystal) nanometer-patterned on its top and bottom surfaces is suggested. For its optimum design the computer simulation is performed and suggests a grating that the spatial frequency between adjacent patterns is 500nm, its height 250nm, duty cycle 50%, and its cross section is rectangular. The angles of transmitted light are nearly the same as the results expected from the generalized Snell's law. Thus the Mathematica code, developed in this experiment, will be applied to designing the optimized LGP. The LGP with nanometer-patterened 1D PC LGP on its both surfaces shows the enhancement of transmitted intensity distribution up to 5.7 times.
High Efficiency Half-bridge DC-DC Converter for an LED Backlight Drive System of LCD Module Inspection Equipment
Yoo, Doo-Hee ; Jeong, Gang-Youl ;
Journal of Institute of Control, Robotics and Systems, volume 14, issue 6, 2008, Pages 535~542
DOI : 10.5302/J.ICROS.2008.14.6.535
This paper presents a high efficiency half-bridge DC-DC converter for an LED backlight drive system of LCD module inspection equipment. The proposed converter improves the converter efficiency using characteristics of the asymmetrical half-bridge converter and the self-driven synchronous rectifier, and thus improves the total efficiency of the LED backlight drive system. The synchronous rectifier applied to the proposed converter is the new topological synchronous rectifier, which changes slightly the transformer structure and the synchronous switch connection in the asymmetrical half-bridge converter with a conventional self-driven synchronous rectifier. Since the proposed converter utilizes the transformer leakage inductor as its resonant inductor, its structure is simplified. The proposed converter well operates under the universal DC input voltage (
). The operational principle and a design example for a 100W prototype are discussed in detail, respectively. Experimental results are shown for the designed prototype converter under universal DC input voltage.
Ultrasonic ACF Bonding Technique for Mounting LCD Driver ICs
Joung, Sang-Won ; Yun, Won-Soo ; Kim, Kyung-Soo ;
Journal of Institute of Control, Robotics and Systems, volume 14, issue 6, 2008, Pages 543~547
DOI : 10.5302/J.ICROS.2008.14.6.543
In the paper, we develop the ultrasonic bonding technique for LCD driver chips having small size and high pin-density. In general, the mounting technology for LCD driver ICs is a thermo-compression method utilizing the ACF (An-isotropic Conductive Film). The major drawback of the conventional approach is the long process time. It will be shown that the conventional ACF method based on thermo-compression can be remarkably enhanced by employing the ultrasonic bonding technique in terms of bonding time. The proposed approach is to apply the ultrasonic energy together with the thermo-compression methodology for the ACF bonding process. To this end, we design a bonding head that enables pre-heating, pressure and ultrasonic excitation. Through the bonding experiments mainly with LCD driver ICs, we present the procedures to select the best combination of process parameters with analysis. We investigate the effects of bonding pressure, bonding time, pre-heating temperature before bonding, and the power level of ultrasonic energy. The addition of ultrasonic excitation to the thermo-compression method reduces the pre-heating temperature and the bonding process time while keeping the quality bonding between the LCD pad and the driver IC. The proposed concept will be verified and demonstrated with experimental results.
Swing-up Control for a Rotary Inverted Pendulum with Restricted Rotation Range
Lee, Y.S. ; Oh, J.J. ; Shim, S.Y. ; Lim, H. ; Seo, J.H. ;
Journal of Institute of Control, Robotics and Systems, volume 14, issue 6, 2008, Pages 548~553
DOI : 10.5302/J.ICROS.2008.14.6.548
In this paper, we propose a new swing-up control strategy for rotary inverted pendulums with restricted rotation range. The control law is derived from a Lyapunov function. The Lyapunov function is defined as the square of the sum of the absolute value of the total mechanical energy and weighted squares of the arm's angular displacement and velocity. By adjusting the weighting parameters in the Lyapunov function, we can affect the swing-up strategy such that the restriction on rotation range can be satisfied. Finally, we verify the performance of the proposed control law through simulation and experiments.
A Stability Analysis Scheme for a Class of First-Order Nonlinear Time-Delay Systems
Choi, Joon-Young ;
Journal of Institute of Control, Robotics and Systems, volume 14, issue 6, 2008, Pages 554~557
DOI : 10.5302/J.ICROS.2008.14.6.554
We analyze the stability property of a class of nonlinear time-delay systems with time-varying delays. We present a time-delay independent sufficient condition for the global asymptotic stability. In order to prove the sufficient condition, we exploit the inherent property of the considered systems instead of applying the Krasovskii or Razumikhin stability theory that may cause the mathematical difficulty of analysis. We prove the sufficient condition by constructing two sequences that represent the lower and upper bound variations of system state in time, and showing the two sequences converge to an identical point, which is the equilibrium point of the system. The simulation results illustrate the validity of the sufficient condition for the global asymptotic stability.
Optical Axis Auto-adjustment of Objective Lens in Optical Disc Drives
Ryoo, Jung-Rae ; Moon, Jung-Ho ; Cho, Ju-Pil ;
Journal of Institute of Control, Robotics and Systems, volume 14, issue 6, 2008, Pages 558~563
DOI : 10.5302/J.ICROS.2008.14.6.558
Optical axis misalignment, which represents the position deviation of the objective lens from the optical axis, is an inevitable assembly error in an optical pick-up. Since the laser power intensity varies with respect to the distance from the optical axis, the misalignment leads to variation of the laser spot power intensity, which is one of the critical factors increasing data bit-error-rate in optical disc drives. In this paper, an auto-adjustment scheme for optical axis alignment is proposed to eliminate the undesirable variation of the laser spot power intensity in optical disc drives. An envelope of the data RF signal is extracted and utilized to detect the optical axis misalignment. Then an adjustment input is added to the driving input of the tracking actuator to shift the objective lens to the optical axis. Finally, the feasibility is verified by experiments.
Extraction of Optimal Time-Delay in Adaptive Command Shaping Filter for Flexible Manipulator Control
Park, Joo-Han ; Rhim, Sung-Soo ;
Journal of Institute of Control, Robotics and Systems, volume 14, issue 6, 2008, Pages 564~572
DOI : 10.5302/J.ICROS.2008.14.6.564
The performance of the direct adaptive time-delay command shaping filter depends on the select time-delay. In the previously introduced direct adaptive command shaping filter, however, the time-delay value is fixed and only the magnitudes of the impulses are learned. In this paper, the authors introduce a new scheme to adapt the time-delay which is to be used in conjunction with the direct adaptive command shaping for the improved vibration suppression in flexible motion system. In order to formulate the time-delay adaptation scheme, the authors have analyzed the effect of the time-delay value on the performance of the direct adaptive command shaping filter. By modifying the direct adaptation formula based on the analysis result the authors have established a set of equations to adapt the time-delay toward the optimal value. Simulation results show the effectiveness of the proposed time-delay adaptation approach for the improved vibration suppression.
Automatic Gait Generation for Quadruped Robot Using a GP Based Evolutionary Method in Joint Space
Seo, Ki-Sung ; Hyun, Soo-Hwan ;
Journal of Institute of Control, Robotics and Systems, volume 14, issue 6, 2008, Pages 573~579
DOI : 10.5302/J.ICROS.2008.14.6.573
This paper introduces a new approach to develop a fast gait for quadruped robot using GP(genetic programming). Planning gaits for legged robots is a challenging task that requires optimizing parameters in a highly irregular and multidimensional space. Several recent approaches have focused on using GA(genetic algorithm) to generate gait automatically and shown significant improvement over previous results. Most of current GA based approaches used pre-selected parameters, but it is difficult to select the appropriate parameters for the optimization of gait. To overcome these problems, we proposed an efficient approach which optimizes joint angle trajectories using genetic programming. Our GP based method has obtained much better results than GA based approaches for experiments of Sony AIBO ERS-7 in Webots environment.
Super-cooled State Cloud Generation System Development for T-50 Supersonic Jet Trainer Icing Test
Lee, Cheol ; Jeon, Cheol-Woo ;
Journal of Institute of Control, Robotics and Systems, volume 14, issue 6, 2008, Pages 580~586
DOI : 10.5302/J.ICROS.2008.14.6.580
Icing cloud generation system was developed to perform the in-flight icing simulation test for T-50 Supersonic Jet Trainer on the ground. The developed system successfully generated the almost natural icing cloud in the super-cooled state (liquid state) below freezing point and with the required LWC (Liquid Water Content). For full-scale aircraft icing test, an icing scaling method was adopted due to the limitation of wind generation speed with open-circuit type blower and its applicability was experimentally verified. Under the required in-flight icing condition based on the icing scaling method, T-50 aircraft subsystems were successfully operated and functionally checked.
A Baseline Constrained LAMBDA method for an Integer Ambiguity Resolution of GNSS Attitude Determination Systems
Park, Chan-Sik ; Teunissen, P.J.G. ;
Journal of Institute of Control, Robotics and Systems, volume 14, issue 6, 2008, Pages 587~594
DOI : 10.5302/J.ICROS.2008.14.6.587
In this paper, an efficient integer ambiguity resolution method for GNSS attitude determination system is described. The proposed method solves the integer least-squares with quadratic equality constraints(ILSQE) problem and shows an expansion of the LAMBDA method can be used to solve it. The solution of ILSQE is shown and an efficient implementation with a LAMBDA based method is given. The method is compared with some other methods. The results of static and dynamic tests show the dramatic improvement of the success rates of integer ambiguity resolution.
Error Analysis of Initial Fine Alignment for Non-leveling INS
Cho, Seong-Yun ;
Journal of Institute of Control, Robotics and Systems, volume 14, issue 6, 2008, Pages 595~602
DOI : 10.5302/J.ICROS.2008.14.6.595
In this paper, performance of the initial alignment for INS whose attitude is not leveled is investigated. Observability of the initial alignment filter is analyzed and estimation errors of the estimated state variables are derived. First, the observability is analyzed using the rank test of observability matrix and the normalized error covariance of the Kalman filter based on the 10-state model. In result, it can be seen that the accelerometer biases on horizontal axes are unobservable. Second, the steady-state estimation errors of the state variables are derived using the observability equation. It is verified that the estimates of the state variables have errors due to the unobservable state variables and the non-leveling tilt angles of a vehicle containing the INS. Especially, this paper shows that the larger the tilt angles of the vehicle are, the larger the estimation errors corresponding to the sensor biases are. Finally, it is shown that the performance of the 8-state model excepting the accelerometer biases on horizontal axes is better than that of the 10-state model in the initial alignment by simulation.
A Fast GPS Signal Acquisition Method for High Speed Vehicles Using INS Velocity and Multiple Correlators
Jeong, Ho-Cheol ; Kim, Jeong-Won ; Hwang, Dong-Hwan ; Lee, Sang-Jeong ; Lee, Tae-Gyoo ; Song, Ki-Won ;
Journal of Institute of Control, Robotics and Systems, volume 14, issue 6, 2008, Pages 603~607
DOI : 10.5302/J.ICROS.2008.14.6.603
This paper proposes a fast acquisition method using INS velocity and multiple correlators for high speed vehicles. In order to reduce acquisition time in GPS receiver, the method utilizes inertial velocity information and multiple correlators. Search range of the Doppler frequency is reduced by using INS velocity and the number of cells at one search can be increased by using multiple correlators. By using both multiple correlators and the INS velocity in the acquisition, search space can be greatly reduced. Experimental results show that the method gives faster signal acquisition performance than the conventional method.
Three-Dimensional Location Tracking System for Automatic Landing of an Unmanned Helicopter
Choo, Young-Yeol ; Kang, Seong-Ho ;
Journal of Institute of Control, Robotics and Systems, volume 14, issue 6, 2008, Pages 608~614
DOI : 10.5302/J.ICROS.2008.14.6.608
This paper describes a location tracking system to guide landing process of an Unmanned Helicopter(UMH) exploiting MIT Cricket nodes. For automatic landing of a UMH, a precise positioning system is indispensable. However, GPS(Global Positioning System) is inadequate for tracking the three dimensional position of a UMH because of large positioning errors. The Cricket systems use Time-Difference-of-Arrival(TDoA) method with ultrasonic and RF(Radio Frequency) signals to measure distances. They operate in passive mode in that a listener attached to a moving device receives distance signals from several beacons located at fixed points on ground. Inevitably, this passive type of implementation causes large disturbances in measuring distances between beacons and the listener due to wind blow from propeller and turbulence of UMH body. To cope with this problem, we proposed active type of implementation for positioning a UMH. In this implementation, a beacon is set up at UMH body and four listeners are located at ground area at least where the UMH will land. A pair of Ultrasonic and RF signals from the beacon arrives at several listeners to calculate the position of the UMH. The distance signals among listeners are synchronized with a counter value appended to each distance signals from the beacon.