239 research outputs found
Characterizing and imaging gross and real finger contacts under dynamic loading
We describe an instrument intended to study finger contacts under tangential dynamic loading. This type of loading is relevant to the natural conditions when touch is used to discriminate and identify the properties of the surfaces of objects â it is also crucial during object manipulation. The system comprises a high performance tribometer able to accurately record in vivo the components of the interfacial forces when a finger interacts with arbitrary surfaces which is combined with a high-speed, high-definition imaging apparatus. Broadband skin excitation reproducing the dynamic contact loads previously identified can be effected while imaging the contact through a transparent window, thus closely approximating the condition when the skin interacts with a non-transparent surface during sliding. As a preliminary example of the type of phenomenon that can be identified with this apparatus, we show that traction in the range from 10 to 1000 Hz tends to decrease faster with excitation frequency for dry fingers than for moist fingers
Haptics: Science, Technology, Applications
This open access book constitutes the proceedings of the 12th International Conference on Human Haptic Sensing and Touch Enabled Computer Applications, EuroHaptics 2020, held in Leiden, The Netherlands, in September 2020. The 60 papers presented in this volume were carefully reviewed and selected from 111 submissions. The were organized in topical sections on haptic science, haptic technology, and haptic applications. This year's focus is on accessibility
Haptics: Science, Technology, Applications
This open access book constitutes the proceedings of the 12th International Conference on Human Haptic Sensing and Touch Enabled Computer Applications, EuroHaptics 2020, held in Leiden, The Netherlands, in September 2020. The 60 papers presented in this volume were carefully reviewed and selected from 111 submissions. The were organized in topical sections on haptic science, haptic technology, and haptic applications. This year's focus is on accessibility
Development of PVDF tactile dynamic sensing in a behaviour-based assembly robot
The research presented in this thesis focuses on the development of tactile event sigÂŹ
nature sensors and their application, especially in reactive behaviour-based robotic
assembly systems.In pursuit of practical and economic sensors for detecting part contact, the application
ofPVDF (polyvinylidene fluoride) film, a mechanical vibration sensitive piezo material,
is investigated. A Clunk Sensor is developed which remotely detects impact vibrations,
and a Push Sensor is developed which senses small changes in the deformation of a
compliant finger surface. The Push Sensor is further developed to provide some force
direction and force pattern sensing capability.By being able to detect changes of state in an assembly, such as a change of contact
force, an assembly robot can be well informed of current conditions. The complex
structure of assembly tasks provides a rich context within which to interpret changes
of state, so simple binary sensors can conveniently supply a lot more information than
in the domain of mobile robots. Guarded motions, for example, which require sensing a
change of state, have long been recognised as very useful in part mating tasks. Guarded
motions are particularly well suited to be components of assembly behavioural modules.In behaviour-based robotic assembly systems, the high level planner is endowed with
as little complexity as possible while the low level planning execution agent deals with
actual sensing and action. Highly reactive execution agents can provide advantages by
encapsulating low level sensing and action, hiding the details of sensori-motor complexity from the higher levels.Because behaviour-based assembly systems emphasise the utility of this kind of qualiÂŹ
tative state-change sensor (as opposed to sensors which measure physical quantities),
the robustness and utility of the Push Sensor was tested in an experimental behaviourbased system. An experimental task of pushing a ring along a convoluted stiff wire is
chosen, in which the tactile sensors developed here are aided by vision. Three differÂŹ
ent methods of combining these different sensors within the general behaviour-based
paradigm are implemented and compared. This exercise confirms the robustness and
utility of the PVDF-based tactile sensors. We argue that the comparison suggests
that for behaviour-based assembly systems using multiple concurrent sensor systems,
bottom-level motor control in terms of force or velocity would be more appropriate
than positional control. Behaviour-based systems have traditionally tried to avoid
symbolic knowledge. Considering this in the light of the above work, it was found
useful to develop a taxonomy of type of knowledge and refine the prohibition
Tribological interactions of the finger pad and tactile displays
This thesis summarise the results of an investigation of the tribological interactions of the human finger pad with different surfaces and tactile displays. In the wide range of analyses of the mechanical properties of the finger pad, an attempt has been made to explain the nature of the interactions based on critical material parameters and experimental data. The experimental data are presented together with detailed modelling of the contact mechanics of the finger pad compressed against a smooth flat surface. Based on the model and the experimental data, it was possible to account of the loading behaviour of a finger pad and derive the Youngâs modulus of the fingerprint ridges. The frictional measurements of a finger pad against smooth flat surfaces are consistent with an occlusion mechanism that is governed by first order kinetics. In contrast, measurements against a rough surface demonstrated that the friction is unaffected by occlusion since Coulombic slip was exhibited. The thesis includes an investigation of critical parameters such as the contact area. It has been shown that four characteristic length scales, rather than just two as previously assumed, are required to describe the contact mechanics of the finger pad. In addition, there are two characteristic times respectively associated with the growth rates of junctions formed by the finger pad ridges and of the real area of contact. These length and time scales are important in understanding how the Archardian-Hertzian transition drives both the large increase of friction and the reduction of the areal load index during persisting finger contacts with impermeable surfaces. Established and novel models were evaluated with statistically meaningful experiments for phenomena such as lateral displacement, electrostatic forces and squeeze-film that have advanced applications
Annual Report 2019 - Institute of Ion Beam Physics and Materials Research
The Institute of Ion Beam Physics and Materials Research conducts materials research for future applications in, e.g., information technology. To this end, we make use of the various possibilities offered by our Ion Beam Center (IBC) for synthesis, modification, and analysis of thin films and nanostructures, as well as of the free-electron laser FELBE at HZDR for THz spectroscopy. The analyzed materials range from semiconductors and oxides to metals and magnetic materials. They are investigated with the goal to optimize their electronic, magnetic, optical as well as structural functionality. This research is embedded in the Helmholtz Associationâs programme âFrom Matter to Materials and Lifeâ. Seven publications from last year are highlighted in this Annual Report to illustrate the wide scientific spectrum of our institute.
After the scientific evaluation in the framework of the Helmholtz Programme-Oriented Funding (POF) in 2018 we had some time to concentrate on science again before end of the year a few of us again had to prepare for the strategic evaluation which took place in January 2020, which finally was also successful for the Institute
Digital fabrication of custom interactive objects with rich materials
As ubiquitous computing is becoming reality, people interact with an increasing number of computer interfaces embedded in physical objects. Today, interaction with those objects largely relies on integrated touchscreens. In contrast, humans are capable of rich interaction with physical objects and their materials through sensory feedback and dexterous manipulation skills. However, developing physical user interfaces that offer versatile interaction and leverage these capabilities is challenging. It requires novel technologies for prototyping interfaces with custom interactivity that support rich materials of everyday objects. Moreover, such technologies need to be accessible to empower a wide audience of researchers, makers, and users. This thesis investigates digital fabrication as a key technology to address these challenges. It contributes four novel design and fabrication approaches for interactive objects with rich materials. The contributions enable easy, accessible, and versatile design and fabrication of interactive objects with custom stretchability, input and output on complex geometries and diverse materials, tactile output on 3D-object geometries, and capabilities of changing their shape and material properties. Together, the contributions of this thesis advance the fields of digital fabrication, rapid prototyping, and ubiquitous computing towards the bigger goal of exploring interactive objects with rich materials as a new generation of physical interfaces.Computer werden zunehmend in GerĂ€ten integriert, mit welchen Menschen im Alltag interagieren. Heutzutage basiert diese Interaktion weitgehend auf Touchscreens. Im Kontrast dazu steht die reichhaltige Interaktion mit physischen Objekten und Materialien durch sensorisches Feedback und geschickte Manipulation. Interfaces zu entwerfen, die diese FĂ€higkeiten nutzen, ist allerdings problematisch. HierfĂŒr sind Technologien zum Prototyping neuer Interfaces mit benutzerdefinierter InteraktivitĂ€t und KompatibilitĂ€t mit vielfĂ€ltigen Materialien erforderlich. Zudem sollten solche Technologien zugĂ€nglich sein, um ein breites Publikum zu erreichen. Diese Dissertation erforscht die digitale Fabrikation als SchlĂŒsseltechnologie, um diese Probleme zu adressieren. Sie trĂ€gt vier neue Design- und FabrikationsansĂ€tze fĂŒr das Prototyping interaktiver Objekte mit reichhaltigen Materialien bei. Diese ermöglichen einfaches, zugĂ€ngliches und vielseitiges Design und Fabrikation von interaktiven Objekten mit individueller Dehnbarkeit, Ein- und Ausgabe auf komplexen Geometrien und vielfĂ€ltigen Materialien, taktiler Ausgabe auf 3D-Objektgeometrien und der FĂ€higkeit ihre Form und Materialeigenschaften zu Ă€ndern. Insgesamt trĂ€gt diese Dissertation zum Fortschritt der Bereiche der digitalen Fabrikation, des Rapid Prototyping und des Ubiquitous Computing in Richtung des gröĂeren Ziels, der Exploration interaktiver Objekte mit reichhaltigen Materialien als eine neue Generation von physischen Interfaces, bei
Haptics: Science, Technology, Applications
This open access book constitutes the proceedings of the 13th International Conference on Human Haptic Sensing and Touch Enabled Computer Applications, EuroHaptics 2022, held in Hamburg, Germany, in May 2022. The 36 regular papers included in this book were carefully reviewed and selected from 129 submissions. They were organized in topical sections as follows: haptic science; haptic technology; and haptic applications
Quantifying Cognitive Efficiency of Display in Human-Machine Systems
As a side effect of fast growing informational technology, information overload becomes prevalent in the operation of many human-machine systems. Overwhelming information can degrade operational performance because it imposes large mental workload on human operators. One way to address this issue is to improve the cognitive efficiency of display. A cognitively efficient display should be more informative while demanding less mental resources so that an operator can process larger displayed information using their limited working memory and achieve better performance. In order to quantitatively evaluate this display property, a Cognitive Efficiency (CE) metric is formulated as the ratio of the measures of two dimensions: display informativeness and required mental resources (each dimension can be affected by display, human, and contextual factors).
The first segment of the dissertation discusses the available measurement techniques to construct the CE metric and initially validates the CE metric with basic discrete displays. The second segment demonstrates that displays showing higher cognitive efficiency improve multitask performance. This part also identifies the version of the CE metric that is the most predictive of multitask performance. The last segment of the dissertation applies the CE metric in driving scenarios to evaluate novel speedometer displays; however, it finds that the most efficient display may not better enhance concurrent tracking performance in driving. Although the findings of dissertation show several limitations, they provide valuable insight into the complicated relationship among display, human cognition, and multitask performance in human-machine systems
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