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31.
Industry case studies in the use of immersive virtual assembly 总被引:1,自引:0,他引:1
Sankar Jayaram Uma Jayaram Young Jun Kim Charles DeChenne Kevin W. Lyons Craig Palmer Tatsuki Mitsui 《Virtual Reality》2007,11(4):217-228
In this paper, we report on two engineering case studies that have been conducted as part of a Virtual Assembly Technology
Consortium. The objectives of the case studies were to determine if immersive virtual assembly capabilities allow industry
assembly situations to be modelled and studied realistically, and to demonstrate the downstream value of the virtual assembly
capabilities in areas such as ergonomics, assembly installation, process planning, installation, and serviceability. What
is of special significance is that instead of modelling simplified problems or perceived representative situations, the case
studies were constructed from actual assembly floor projects and situations encountered at industry member sites and with
considerable participation from industry engineers and manufacturing shop floor personnel. Based on the success of the case
studies, the consortium members inferred that virtual assembly methods are poised to move out of the realm of special projects
and test scenarios to deployment in the actual design and manufacturing cycle. However, in order to be truly accepted in industry,
there are still issues to be addressed in terms of ease of use, portability of the applications, and preparation of the models
for the evaluations. Thus, the case studies added a new dimension to the exploration and understanding of how this new technology
could be of practical value in industry. 相似文献
32.
Organometallic Bonding in an Ullmann‐Type On‐Surface Chemical Reaction Studied by High‐Resolution Atomic Force Microscopy
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Shigeki Kawai Ali Sadeghi Toshihiro Okamoto Chikahiko Mitsui Rémy Pawlak Tobias Meier Jun Takeya Stefan Goedecker Ernst Meyer 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(38):5303-5311
The on‐surface Ullmann‐type chemical reaction synthesizes polymers by linking carbons of adjacent molecules on solid surfaces. Although an organometallic compound is recently identified as the reaction intermediate, little is known about the detailed structure of the bonded organometallic species and its influence on the molecule and the reaction. Herein atomic force microscopy at low temperature is used to study the reaction with 3,9‐diiododinaphtho[2,3‐b:2′,3′‐d]thiophene (I‐DNT‐VW), which is polymerized on Ag(111) in vacuum. Thermally sublimated I‐DNT‐VW picks up a Ag surface atom, forming a C? Ag bond at one end after removing an iodine. The C? Ag bond is usually short‐lived, and a C? Ag? C organometallic bond immediately forms with an adjacent molecule. The existence of the bonded Ag atoms strongly affects the bending angle and adsorption height of the molecular unit. Density functional theory calculations reveal the bending mechanism, which reveals that charge from the terminus of the molecule is transferred via the Ag atom into the organometallic bond and strengths the local adsorption to the substrate. Such deformations vanish when the Ag atoms are removed by annealing and C? C bonds are established. 相似文献
33.
Accurate localization is required for autonomous robots to navigate in cluttered environments safely. Therefore, Extended Kalman Filter (EKF) and Unscented Kalman Filter (UKF), which incorporate probabilistic concepts as localization methods, have been researched up to now. It should be noted, however, that the errors of kinematic parameters such as wheel diameter, tread, and mounting sensor offset are not enough considered in conventional works. We propose an Augmented UKF-SLAM (AUKF-SLAM), which is an extension of the UKF-SLAM and can estimate the kinematic parameters including a sensor mounting offset together with the localization and mapping. The UKF-SLAM and the AUKF-SLAM are compared through some simulations to show that the proposed AUKF-SLAM is more accurate than the UKF-SLAM. Furthermore, localization experiments with only odometry are conducted using a real robot. The experimental results show to demonstrate that the localization using kinematic parameters estimated by the AUKF-SLAM is more accurate than that using values measured by hand in advance. Through some experimental verifications in an elevator hall, cluttered rooms, and a long distance corridor, it is confirmed that the proposed AUKF-SLAM which simultaneously estimates the effective kinematic parameters largely contributes to the total accuracy improvement of SLAM. 相似文献
34.
Isaku Nagai Genki Yamauchi Keiji Nagatani Keigo Watanabe Kazuya Yoshida 《Advanced Robotics》2013,27(15):1147-1160
We propose a novel method for positioning a mobile robot in an outdoor environment using lasers and optical sensors. Position estimation via a noncontact optical method is useful because the information from the wheel odometer and the global positioning system in a mobile robot is unreliable in some situations. Contact optical sensors such as computer mouse are designed to be in contact with a surface and do not function well in strong ambient light conditions. To mitigate the challenges of an outdoor environment, we developed an optical device with a bandpass filter and a pipe to restrict solar light and to detect translation. The use of two devices enables sensing of the mobile robot’s position, including posture. Furthermore, employing a collimated laser beam allows measurements against a surface to be invariable with the distance to the surface. In this paper, we describe motion estimation, device configurations, and several tests for performance evaluation. We also present the experimental positioning results from a vehicle equipped with our optical device on an outdoor path. Finally, we discuss an improvement in postural accuracy by combining an optical device with precise gyroscopes. 相似文献
35.
Xin Yang Keigo Watanabe Kiyotaka Izumi Kazuo Kiguchi 《International journal of control》2013,86(10):949-963
In this paper, we propose a decentralized control system for transporting a single object by multiple non-holonomic mobile robots. Each agent used in the proposed system has two arms, which can steer around a joint offset from the centre point between two driving wheels. One of these mobile robots acts as a leader, who is assumed to be able to plan and to manipulate the omnidirectional motion of the object by using a resolved velocity control. Other robots, referred to as followers, cooperatively transport the object by keeping a constant relative position with the object using a simple PI control. Different from conventional leader–follower type systems that transport an object by multiple robots in coordination, the present followers can plan an action based on their local coordinate and need no absolute positional information. In addition, as a special case, a system consisting of only two robots is introduced, in which the follower robot not only has an arm length controller to follow the leader but also has a fuzzy controller as an avoidance controller to avoid obstacles or a posture controller to keep a desired posture of the object. Simulation results are given to demonstrate the good performance of the proposed systems. 相似文献
36.
37.
Kuge S. Kato T. Furutani K. Kikuda S. Mitsui K. Hamamoto T. Setogawa J. Hamade K. Komiya Y. Kawasaki S. Kono T. Amano T. Kubo T. Haraguchi M. Nakaoka Y. Akiyama M. Konishi Y. Ozaki H. Yoshihara T. 《Solid-State Circuits, IEEE Journal of》2000,35(11):1680-1689
A 200-MHz double-data-rate synchronous-DRAM (DDR-SDRAM) was developed. The chip contains a delay-locked loop (DLL) which performs over a wide range of operating conditions. Post-mold-tuning allows precise replica programming. A 200-MHz intra-chip data bus is suitable for DDR operation 相似文献
38.
K Kawabata K Mitsui T Uno K Tamura K Tsurugi 《Canadian Metallurgical Quarterly》1999,259(1-2):112-119
The GTS1 gene product, Gts1p, has pleiotropic effects on the timing of budding, cell size, heat tolerance, sporulation and the lifespan of the yeast Saccharomyces cerevisiae. In this study, we found (using the yeast two-hybrid system) that Gts1p forms homodimers throughout the 18-amino acid region 296-313 which has considerable similarity to a region downstream of the Walker nucleotide-binding motif A of some ATP-binding cassette (ABC) transporters. The region contains two aspartic acid residues at 301 and 310 preceded by hydrophobic amino acid residues, and Gts1p with an Asp310 to Ala substitution showed considerably reduced homodimerization, as shown by the two-hybrid assay. Overexpression of the point-mutated Gts1p did not efficiently induce the Gts1p-related phenotypes described above, suggesting that the homodimerization of Gts1p is required for it to function in vivo. The C-terminal cytoplasmic domain of the yeast ABC transporters Mdl1p (multidrug resistance-like transporter) and Ycf1p (yeast cadmium factor or glutathione S-conjugate pump) bound to Gts1p in the two-hybrid system, and the heterodimerization activity of the Gts1p with the Asp301 to Ala substitution was more affected than the Gts1p with the Asp310 to Ala substitution. Overexpression of GTS1 considerably reduced, and disruption of GTS1 slightly decreased, cellular resistance to cycloheximide, cadmium, cisplatin and 1-chloro-2,4-dinitrophenol, which (except for cycloheximide) are all substrates of Ycf1p. These results suggest that Gts1p interacts with some ABC transporters through the binding site overlapping that of homodimerization and modulates their activity. 相似文献
39.
Mechanisms for electrical characteristic changes in MOSFET caused by electron beam irradiation were studied using a SEM-based nano-probing system. A shift in Vth occurs when a hole is trapped in a defect (oxygen vacancy) in the gate dielectric layer. Holes are generated when the plasmon is excited by electron beam irradiation. Further, an electric field is created by the positive charge-up resulting from electron beam irradiation of the ILD, causing an increase in leakage between gate and drain leading to an increase in Ioff. This study shows that advanced devices can be measured using a SEM-based nano-probing system without inducing electrical characteristic changes by optimizing the measurement conditions such as acceleration voltage, electron beam current, image magnification, ILD thickness, and electron beam irradiation time. 相似文献
40.
A diisocyanate baring ether bonds, 1,2-bis(isocyanate)ethoxyethane (TEGDI), was used for the preparation of polyurethane elastomers (PUEs). The PUEs were synthesized with either TEGDI or HDI, poly(oxytetramethylene) glycol (PTMG), and curing agents by a prepolymer method. 1,6-Hexamethylene diisocyanate (HDI) was also used as a control diisocyanate. The TEGDI-based PUEs exhibited highly softened property on account of flexibility of TEGDI itself and weaker phase separation. Another TEGDI-based PUEs were prepared with either poly(oxypropylene) glycol (PPG) or poly(caprolactone) glycol (PCL). Microphase-separated structure of these TEGDI-based PUEs are quite different from those with general diisocyanates and the PUEs were made be greatly softened. 相似文献