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38th IEEE Photovoltaic Specialists Conference, PVSC 2012

作者： Rühle, K. Glunz, S.W. Kasemann, M. University of Freiburg Department of Microsystems Engineering 79110 Freiburg Germany Fraunhofer Institute for Solar Energy Systems ISE 79110 Freiburg Germany

ISBN: (纸本)9781467300643

The common design rules for outdoor solar cells do not apply necessarily for indoor photovoltaic cells due to differences in spectra and intensities. Since no general standard for indoor conditions is currently available, the first aim of this paper is to present a statistical approach encompassing the diversity of available intensities and spectra which shall enable a systematic derivation of a standard for indoor conditions. In a second step, the influences of injection-and spectra-dependent parameters on cell efficiencies are studied with the focus on indoor conditions. It is shown that the parallel resistance has to be increased above 50 kΩcm2 in order to achieve an efficiency above 10% at intensities below 10-3 W/cm2 (∼0.01 suns). The influence of the series resistance is negligible in this intensity range, allowing values in the order of 10 Ωcm2 without appreciable efficiency reduction. This gives room for wider design variations with respect to base and emitter doping, optimization of bulk-, surface- and emitter recombination, contact optimization and back contact cell designs. The combined evaluation of possible photovoltaic cell parameters show that efficiencies of more than 10% at intensities as low as 10-4 W/cm2 are accessible. © 2012 IEEE.

关键词： Energy harvesting

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From discrete event simulation to virtual reality environments

From discrete event simulation to virtual reality environmen...

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Workshop on Computer Safety, Reliability, and Security, SAFECOMP 2012

作者： Nielebock, Sebastian Ortmeier, Frank Schumann, Marco Winge, André Computer Systems in Engineering Otto-von-Guericke University of Magdeburg Germany Fraunhofer Institute for Factory Operation and Automation IFF Magdeburg Germany

ISBN: (纸本)9783642336744

Today's technical systems are often very complex. System dynamics are often hard to predict for humans. However, understanding system behavior is crucial for evaluating design variants and finding errors. One way to cope with this problem is to build logical or virtual simulations. Logical simulations are often very abstract, but can simulate complex behavioral sequences. Virtual reality (VR) simulation is very good for experiencing the system in a view close to reality. However, it is very often static or has only limited dynamics. Until now both approaches exist in relative isolation. In this paper, we report on our experiences in building a mixed simulation, here a discrete event simulator (DES) is coupled with a virtual reality (VR) environment. We will focus on technical and conceptual challenges, but also present possible use cases for user interaction in this strategy to make more detailed investigations possible. Finally a prototype based on the simulation tool SLX and the virtual reality environment Virtual Development and Training Platform is used to evaluate the approach. © 2012 Springer-Verlag Berlin Heidelberg.

关键词： Discrete event simulation

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Automatic camera and kinematic calibration of a complex service robot 1

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22nd conference on Autonomous Mobile systems, AMS 2012

作者： Haug, Sebastian A. Weisshardt, Florian Verl, Alexander Fraunhofer Institute for Manufacturing Engineering and Automation IPA Robot and Assistive Systems - Service Robot Applications Nobelstr. 12 70569 Stuttgart Germany

ISBN: (数字)9783642322174

ISBN: (纸本)9783642322167

Service robots operate in unstructured environments where precise and reliable calibration of vision and manipulation components is essential for successful and safe operation. So far the calibration of the service robot Care-O-bot® 3 covering only the camera sensors is not precise enough for manipulation of small objects and involves many manual error-prone steps. In an evolving research context there is constant need for recalibration and therefore a complete and precise yet quick and easy to use calibration procedure is desired. We propose an automated calibration process covering the cameras and kinematic components of a service robot and present an open-source implementation for Care-O-bot® 3. © 2012 Springer-Verlag Berlin Heidelberg.

关键词： Calibration

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An integrated solution for compensation of refractive index drop and curve change in high precision glass molding 12

An integrated solution for compensation of refractive index ...

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12th International Conference of the European Society for Precision engineering and Nanotechnology, EUSPEN 2012

作者： Klocke, Fritz Dambon, Olaf Su, Lijuan Wang, Fei He, Peng Liu, Gang Yi, Allen Y. 1Fraunhofer Institute for Production Technology IP Aachen Germany Department of Integrated Systems Engineering Ohio State University United States

ISBN: (纸本)9780956679000

In precision glass molding, refractive index change and geometrical deviation (curve change) occurred during molding process can result in substantial amount of optical property change to the glass lenses. Previously, refractive index drop and curve change were investigated in separate studies by the authors. However, optical performance of a molded glass lens depends on both refractive index and geometry. In order to fabricate glass aspherical lenses with optimal performance, both refractive index and curve have to be considered simultaneously. This research presented an integrated compensation procedure for both refractive index and curve changes of a molded glass lens. First, group refractive index change predicted by finite element method simulation was used to provide a compensated lens design. Second, curve change of the molded aspherical glass lenses was compensated with a previously developed numerical simulation approach, which was used to modify the mold shape to compensate for thermal shrinkage of the molded glass lenses. Measurements of geometry and optical performance confirmed that the molded lenses perform as specified by the original design. It also demonstrated that finite element method assisted compensation procedure can be used to predict the final optical performance of compression molded glass components.

关键词： Refractive index

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Pattern-based integrative design of molded interconnect devices (MID)

Pattern-based integrative design of molded interconnect devi...

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12th International Design Conference, DESIGN 2012

作者： Dumitrescu, R. Gaukstern, T. Jürgenhake, C. Gausemeier, J. Kühn, A. Department Product Engineering Fraunhofer Institute for Production Technology IPT Project Group Mechatronic Systems Design Zukunftsmeile 1 33102 Paderborn Germany

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Model-based development of context-aware applications using the MILEO-context server

Model-based development of context-aware applications using ...

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IEEE Annual Conference on Pervasive Computing and Communications Workshops (PerCom)

作者： Manfred Wojciechowski Markus Wiedeler Fraunhofer Institute of Software and Systems Engineering (ISST) Dortmund Germany

In this paper we describe our methodology for building context-aware applications. It supports a systematic definition, conception and development of the context-aware features of an application along the different phases of a software development process. Its application has helped us in the discussion and conception of these features in project teams with non-technical domain experts. A context meta-model defines the common concepts and features of concrete context models, which are used in the transition between the different development phases. This context meta-model has been implemented in our context server MILEO. Thus it allows a model-based realization of an application's context logic without explicit programming. We describe how we have applied our methodology in the project `Daily Care Journal'.

关键词： Context Context modeling Servers Adaptation models Context-aware services Sensors Programming

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User-centered Design and Evaluation of an Integrated AR-VR System for Tele-Maintenance

User-centered Design and Evaluation of an Integrated AR-VR S...

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IEEE International Conference on systems, Man, and Cybernetics

作者： Michael Kleiber Thomas Alexander Carsten Winkelholz Christopher M. Schlick Human-Machine-Systems Engineering Fraunhofer FKIE Institute of Industrial Engineering and Ergonomics RWTH Aachen University

ISBN: (纸本)9781467317139

In case of undocumented machine failures on-site maintenance personnel can cooperate with a remote expert using telecommunication equipment. We present a new concept for a maintenance system which provides a synchronous shared visual workspace even when only limited bandwidth is available. A mechanic uses an Augmented Reality (AR) system which is connected to the Virtual Reality (VR) system of a remote expert. The expert interactively creates 3D instructions on his VR system that are displayed on a hand-held tablet computer of the mechanic. The mechanic considers these instructions during his maintenance work but can also interact with the live AR view to create spatial references for the expert. The system was evaluated by 18 experienced automobile mechanics. The maintenance task consisted of the disassembly of the camshaft housing of an internal combustion engine. The results show that participants completed more tasks and used less verbal instructions when using the VR system compared to a video system.

关键词： Virtual reality Augmented reality Evaluation mechanic TELEMAINTENANCE Telecommunication Device Maintenance engineering instruction Professional personnel video equipment Variable reluctance User-centred design disassembly and assembly site maintenance

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Singularity-free state-space representation for non-holonomic, omnidirectional undercarriages by means of coordinate switching

Singularity-free state-space representation for non-holonomi...

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2012 IEEE/RSJ International Conference on Intelligent Robots and systems

作者： Christian Connette Martin Hägele Alexander Verl Department of Robot Systems Fraunhofer Institute for Manufacturing Engineering and Automation Stuttgart Germany

Non-holonomic, omnidirectional undercarriages that are composed of steered standard wheels seem to provide a solid compromise between versatility, flexibility and high robustness against various ground conditions. However, such undercarriages are characterized by the occurrence of a number of singular configurations. To avoid these singular configurations most control-approaches restrict the admissible configuration-space thus eventually reducing the mobility and flexibility of the undercarriage. Within this work a state-space representation that forms a locally singularity-free atlas of the admissible configuration-space is presented. Based on this state-space description a switching based controller is developed that incorporates the former singular regions into the used configuration space and thus allows to exploit the full flexibility of non-holonomic, omnidirectional undercarriages. The implemented controller is quantitatively and qualitatively evaluated and compared to one approach that avoids the singular regions and one that completely neglects the non-holonomic bindings.

关键词： Wheels Robot kinematics Mobile robots Switches Aerospace electronics

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Battery management network for fully electrical vehicles featuring smart systems at cell and pack level

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16th International Forum on Advanced Microsystems for Automotive Applications, AMAA 2012

作者： Otto, A. Rzepka, S. Mager, T. Michel, B. Lanciotti, C. Günther, T. Kanoun, O. Department Micro Materials Center Fraunhofer Institute for Electronic Nano Systems ENAS Technologie-Campus 4 09126 Chemnitz Germany Department Advanced System Engineering Fraunhofer Institute for Electronic Nano Systems ENAS Warburger Str. 100 33098 Paderborn Germany Italy Chemnitz University of Technology Reichenhainer Str. 70 09126 Chemnitz Germany

ISBN: (纸本)9783642296727

Current limitations of battery systems for fully electric vehicles (FEV) are mainly related to performance, driving range, battery life, re-charging time and price per unit. New cell chemistries are able to mitigate these drawbacks, but are more prone to catastrophic failures due to a thermal runaway than current solutions. Therefore, new and more advanced management strategies are necessary to be able to safely prevent the energy storage system from ever coming into this critical situation. In this paper, a novel battery management system (BMS) architecture is introduced, which will be able to meet these high requirements by introducing a network that has smart satellite systems in each macro-cell or even in each individual cell. In addition, the issues of safety and reliability to be considered for the integration and packaging technologies of the smart satellite systems will be described as well. The work reported is part of the European project 'Smart-LIC', which is supported by EPoSS, and the German project 'HotPowCon'.

关键词： Lithium-ion batteries

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Degradation study on optical materials for concentrator photovoltaics

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AIP Conference Proceedings 2012年第1期1477卷 276-280页

作者： Fabian Eltermann Kerstin Roeder Maike Wiesenfarth Juergen Wilde Andreas W. Bett Fraunhofer Institute for Solar Energy Systems Freiburg Germany University of Freiburg Department of Microsystems Engineering Freiburg Germany

In this work the impact of accelerated aging on the spectral transmission and the mechanical robustness of silicone elastomers for concentrator photovoltaic applications was investigated. Therefore, specific test samples were manufactured. The samples were annealed at 150 °C to assure a complete cross-linking. These samples were exposed to humidity freeze, to a pressure cooker test, and to UV light. To investigate optical materials under UVA intensity up to 10 W/cm2 a test setup was developed. Thus, a UV dosage of 10000 kWh/m2 was applied to the silicone samples after thermal treatment. The mean transmission was used as a measure to identify changes in the spectral behavior and was, therefore, compared after the stress tests with the initial value. No total failures but rather degradation was observed, mainly in the range of ultraviolet and visible light. In addition, the shear strengths for the silicone elastomers were compared before and after stress.

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