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191.
Jong-Hwi Seo Jae-Chul Hwang Yong-Won Choi Hong-Jae Yim 《Journal of Mechanical Science and Technology》2009,23(4):1035-1039
Recently, the size of raw glass has been greatly increased in the new generation Liquid Crystal Display (LCD) technology.
To handle bigger and heavier glasses, it is necessary to develop a large scale LTR (LCD Transfer Robot) to support various
complicated LCD fabrication processes. This adjustment will result in difficult design problems such as vibration, handling
accuracy deterioration, and high stress due to heavier dynamic loads. In turn, these will result in inaccurate transfer motion
and fatigue cracks.
In this paper, the dynamic simulation technique is introduced to validate a baseline design and to propose new and improved
designs for the best performance of heavy-scaled LCD transfer robots. The dynamic models and analysis results were verified
by real experiments including strain measure test and motor power test. Using the verified simulation model, some dynamic
situations such as the robot’s emergency stop and free fall situation, which were not impossible to test using the real proto
robot, were analyzed and predicted using the simulation model.
This paper was presented at the 4th Asian Conference on Multibody Dynamics(ACMD2008), Jeju, Korea, August 20–23, 2008.
Jong-Hwi Seo received a B.S. M.S. and Ph.D. degrees from Ajou University in 1998, 2000 and 2005, respectively. He is currently a senior
engineer in Mechatronics and Manufacturing Technology Center of Samsung Electronics Co. His research interests are in the
area of multibody dynamics, robotics and mechanism design.
Jae Chul Hwang received a B.S., M.S., and Ph.D. degrees in mechanical engineering from Seoul National University, Korea, in 1996, 1998,
and 2002, respectively. He is currently a senior engineer in Mechatronics and Manufacturing Technology Center of Samsung Electronics
Co., Ltd. His research interests are in the area of kinematics and dynamics of serial and parallel kinematic robot.
Yong-Won Choi received a M.S degree in Mechanical Engineering from Korea University in 1993. He has worked for Samsung Electronics, Ltd
from 1993 and is currently a principle engineer at Robot Mechanism Part in Mechatronics and Manufacturing Technology Center
of Samsung Electronics Co. He is interest in the area of robotics, control and mechanism design.
Hong Jae Yim received B.S. and M.S degrees in mechanical engineering from Seoul National University, Korea, in 1979, and 1983, respectively.
He received Ph.D degree from Univ. of Iowa, USA. He is currently a professor in School of Mechanical & Automotive Engineering,
Kookmin University. His research interests are in the area of computer aided kinematics and dynamics of mechanical systems. 相似文献
192.
This paper considers a distributed job shop scheduling problem where autonomous sub-production systems share common machines with each other. Each sub-production system is responsible for the scheduling of a set of jobs to minimise the total completion time on shared machines. A sub-production system has ultimate responsibility on maintaining private information such as objective function, processing time and routings on shared machines. Also sub-production systems must cooperate each other in order to achieve a global goal while sharing minimum of private information. In this research, we propose a distributed cooperation method in which sub-production systems and shared machines interact with one another to find a compromised solution between a locally optimised solution and a system-wide solution. We tested the proposed method for small, medium and large size of job shop scheduling problems and compared to a global optimal solutions. The proposed method shows promising results in terms of solution qualities and computational times. 相似文献
193.
Yang Gyun Oh Yong Hun Kim Hyeong Soon Yim Chul Jin Choi Seung Min Baek Sang Jeong Lee 《能源与动力工程:英文版》2013,(8):1478-1486
The issue of CCF (common cause failure) in digital I & C (instrumentation and control) systems is of great interest because an increasing number of such systems are implemented in nuclear power plants. For the mitigation of ATWS (anticipated transients without scram) as well as CCF within the PPS (plant protection system) and the ESF-CCS (engineered safety feature-component control system), the ADPS (advanced diverse protection system) has been developed by KEPCO E & C (KEPCO Engineering and Construction) Company for new nuclear units in Korea. As compared to the DPS (diverse protection system) design of APR1400, the ADPS has a diverse safety injection function considering a LBLOCA (large break loss of coolant accident) concurrent with the CCF of the PPS and ESF-CCS. Besides the function of SIAS (safety injection actuation signal) initiation, several CCF avoidance features, such as the changes of software design classification, communication methods, equipment platform, and man-machine interfaces, are introduced to enhance the reliability of the ADPS. In addition, the ADPS has recently incorporated four redundant channels with 2-out-of-4 voting logics to enhance its fault tolerant capability. Therefore, it is expected that the ADPS can provide an enhanced reliability regarding possible CCFs in the safety-grade digital I & C systems as well as the ADPS itself. 相似文献
194.
Jong Hwi Seo Hong Jae Yim Jae Chul Hwang Yong Won Choi Dong Il Kim 《Journal of Mechanical Science and Technology》2008,22(4):722-730
The objective of the present study is to develop a design methodology for the large scale heavy duty robot to meet the design
requirements of vibration and stress levels in structural components resulting from exposure of system modules to LCD (Liquid
Crystal Display) processing environments. Vibrations of the component structures significantly influence the motion accuracy
and fatigue damage. To analyze and design a heavy duty robot for LCD transfer, FE and multi-body dynamic simulation techniques
have been used. The links of a robot are modeled as flexible bodies using modal coordinates. Nonlinear mechanical properties
such as friction, compliance of reducers and bearings were considered in the flexible multi-body dynamics model. Various design
proposals are investigated to improve structural design performances by using the dynamic simulation model. Design sensitivity
analyses with respect to vibration and stresses are carried out to search an optimal design. An example of an 8G (8th-Generation)
LTR (LCD Transfer Robot) is illustrated to demonstrate the proposed methodology. Finally, the results are verified by real
experiments including vibration testing. 相似文献
195.
For physical and chemical sensing applications, a bimorph actuated staggered mirror (BASM) microsensor was designed and fabricated
by surface micromachining using a transparent quartz substrate. While the conventional cantilever sensors have angular deflection,
BASM’s moving mirror performs piston-type pure vertical motion in response to environmental stimuli like temperature change
and surface stress change due to molecular adsorption. Since the sensor itself has a fixed or reference mirror as well as
a moving mirror, 1) an interferometric measurement is possible without an additional reference mirror in off-axis measurement
setup, and 2) vibration measurement noise can be reduced. For preliminary test purposes, interferometric measurement using
an optical setup was performed for temperature change. At He-Ne line (632.8 nm), a temperature change of ∼0.8 K caused a minimum-to-maximum
interferometric light intensity change which corresponds to ∼144 nm shift of the moving mirror part. An optical diffraction
analysis was performed and optimal device parameters were found to maximize the sensor sensitivity. 相似文献
196.
Physiochemical properties and prolonged release behaviours of chitosan-denatured β-lactoglobulin microcapsules for potential food applications 总被引:1,自引:0,他引:1
Chitosan (CS) and β-lactoglobulin (βlg) double-wall coating was designed as a shell structure to achieve prolonged release of core material in the gastrointestinal tract (GI) for potential food applications. A model core material, brilliant blue (BB) dye, was incorporated into CS as the primary wall material, and subsequently, denatured βlg, a secondary wall material, was used to coat the outer layer. The strongest interaction occurred between 0.5% (w/v) βlg and 0.5% (w/v) CS at pH 5.5 ± 0.1, where the opposite charges of CS and βlg formed a complex, which is especially favourable in acidic beverage systems. Under simulated stomach conditions, a denatured-βlg coat resisted acid conditions and pepsin hydrolysis for 2 h. While mimicking small intestine conditions, βlg was degraded by pancreatin, causing the release of BB-loaded CS to the intestinal fluid at a constant rate. The sustained release of core material later in the GI tract provided an optimal absorption rate in the small intestine. 相似文献
197.
Combustion emissions are a major contributor to degradation of air quality and pose a risk to human health. We evaluate and apply a multiscale air quality modeling system to assess the impact of combustion emissions on UK air quality. Epidemiological evidence is used to quantitatively relate PM(2.5) exposure to risk of early death. We find that UK combustion emissions cause ~13,000 premature deaths in the UK per year, while an additional ~6000 deaths in the UK are caused by non-UK European Union (EU) combustion emissions. The leading domestic contributor is transport, which causes ~7500 early deaths per year, while power generation and industrial emissions result in ~2500 and ~830 early deaths per year, respectively. We estimate the uncertainty in premature mortality calculations at -80% to +50%, where results have been corrected by a low modeling bias of 28%. The total monetized life loss in the UK is estimated at £6-62bn/year or 0.4-3.5% of gross domestic product. In Greater London, where PM concentrations are highest and are currently in exceedance of EU standards, we estimate that non-UK EU emissions account for 30% of the ~3200 air quality-related deaths per year. In the context of the European Commission having launched infringement proceedings against the UK Government over exceedances of EU PM air quality standards in London, these results indicate that further policy measures should be coordinated at an EU-level because of the strength of the transboundary component of PM pollution. 相似文献
198.
Byung-Seung Yim Yumi Kwon Seung Hoon Oh Jooheon Kim Yong-Eui Shin Seong Hyuk Lee Jong-Min Kim 《Microelectronics Reliability》2012,52(6):1165-1173
This study investigated the effect of the viscosity of the ECAs using a low-melting-point alloy (LMPA) filler on its bonding characteristics. The curing behaviors of the ECAs were determined using Differential Scanning Calorimetry (DSC), and ECA temperature-dependant viscosity characteristics were observed using a torsional parallel rheometer. The wetting test was conducted to investigate the reduction capability of ECAs and the flow-coalescence-wetting behavior of the LMPAs in ECAs. Electrical and mechanical properties were determined and compared to those with commercial ECAs and eutectic tin/lead (Sn/Pb) solder. In the metallurgically interconnected Quad Flat Package (QFP) joint, a typical scallop-type Cu–Sn intermetallic compound (IMC) layer formed at the upper SnBi/Cu interface after curing process. On the other hand, a (Cu, Ni)6Sn5 IMC layer formed on the SnBi/ENIG interface. In addition, the fracture surface exhibited by cleavage fracture mode and the fracture was propagated along the Cu–Sn IMC/SnBi interface. The extremely low-level viscosity of ECAs had a significant influence on the flow-coalescence-wetting behavior of the LMPAs in ECAs and also on the interconnection properties. Stable interconnected assemblies showed good electrical and mechanical properties. 相似文献
199.
Lee SH Heo HS Jeong KE Yim JH Jeon JK Jung KY Ko YS Kim SS Park YK 《Journal of nanoscience and nanotechnology》2011,11(1):759-762
The catalytic cracking of oilsand bitumen was performed over nanoporous materials at atmospheric conditions. The yield of gas increased with application of nanoporous catalysts, with the catalytic conversion to gas highest for Meso-MFI. The cracking activity seemed to correlate with pore size rather than weak acidity or surface area. 相似文献
200.
We have investigated the carrier dynamics and activation energy of CdxZn(1-x)Te/ZnTe quantum dots (QDs) on GaAs and Si substrates. The carrier dynamics of QDs on GaAs and Si substrates is studied using time-resolved photoluminescence (PL) measurements, revealing shorter exciton lifetimes of QDs on Si substrate. In particular, the activation energy of electrons confined in QDs on the GaAs substrate, as obtained from temperature-dependent PL spectra, is higher than that of electrons confined in QDs on the Si substrate. Both results confirm that defects and dislocations in QDs on the Si substrate provide nonradiative channels. 相似文献