W-FYD: a Wearable Fabric-based Display for Haptic Multi-Cue Delivery and Tactile Augmented Reality

Despite the importance of softness, there is no evidence of wearable haptic systems able to deliver controllable softness cues. Here, we present the Wearable Fabric Yielding Display (W-FYD), a fabric-based display for multi-cue delivery that can be worn on user's finger and enables, for the first time, both active and passive softness exploration. It can also induce a sliding effect under the finger-pad. A given stiffness profile can be obtained by modulating the stretching state of the fabric through two motors. Furthermore, a lifting mechanism allows to put the fabric in contact with the user's finger-pad, to enable passive softness rendering. In this paper, we describe the architecture of W-FYD, and a thorough characterization of its stiffness workspace, frequency response and softness rendering capabilities. We also computed device Just Noticeable Difference in both active and passive exploratory conditions, for linear and non-linear stiffness rendering as well as for sliding direction perception. The effect of device weight was also considered. Furthermore, performance of participants and their subjective quantitative evaluation in detecting sliding direction and softness discrimination tasks are reported. Finally, applications of W-FYD in tactile augmented reality for open palpation are discussed, opening interesting perspectives in many fields of human-machine interaction

The Role of Fluorescence and Human Factors in Quantitative Transdermal Blood and Tissue Analysis Using NIR Raman Spectroscopy

This research is part of an ongoing project aimed at the application of combined near infrared (NIR) Raman and fluorescence spectroscopy to noninvasive in vivo blood analysis including but not limited to glucose monitoring. Coping with practicalities of human factors and exploring ways to obtain and use knowledge gained about autofluorescence to improve algorithms for blood and tissue analysis are the general goals of this research. Firstly, the study investigated the various sources of human factors pertinent to our concerns, such as fingerprints, turgor, skin hydration and pigmentation. We then introduced specialized in vivo apparatus including means for precise and reproducible placement of the tissues relative to the optical aperture, i.e., the position detector pressure monitor (PDPM). Based on solid instrumental performances, appropriate methodology is now provided for applying and maintaining pressure to keep surface tissues immobile during experiments while obtaining the desired blood content and flow. Secondly, in vivo human fingertip skin autofluorescence photobleaching under 200 mW 830 nm NIR irradiation is observed and it is characterized that: i) the majority of the photobleached fluorescence originates from static tissue not blood, ii) the bleaching (1/e point) occurs in 101-102 sec timescale, and also iii) a photobleached region remains bleached for at least 45 min but recovers completely within several hours. A corresponding extensive but not exhaustive in vitro systematic study narrowed down the major contributors of such fluorescence and bleaching to collagen, melanin, plasma and hemoglobin: two major static tissue constituents and two major blood proteins. Thirdly, we established that measuring the inelastic and elastic emissions simultaneously leads to a sensitive probe for volume changes of both red blood cells and plasma. An algorithm based on measurements obtained while performing research needed for this thesis, as well as some empirical calibration approaches, was presented. The calibrated algorithm showed real potential to track hematocrit variations in cardiac pulses, centrifugal loading, blood vessel blockage using tourniquet, and even during as subtle an occurrence as in a Valsalva maneuver. Finally, NIR fluorescence and photochemistry of pentosidine, a representative of the advanced glycation endproducts (AGEs) which accumulate with age and hyperglycemia, was studied. The results indicate that oxygen plays a pivotal role in its photobleaching process. We hypothesized and offered proofs showing that pentosidine is a 1O2 sensitizer that is also subject to attack by the 1O2 resulting in the photobleaching that is observed when probing tissue using NIR. The photobleaching reaction is kinetically first order in pentosidine and ground state oxygen, and in vivo effectively first order with NIR irradiation also

REAL-TIME MONITORING OF PROBE-TISSUE PRESSURE EFFECTS ON IN VIVO SKIN OPTICAL SPECTROSCOPY USING A PRESSURE SENSITIVE FIBEROPTIC PROBE

Master'sMASTER OF ENGINEERIN

ReSCon '11, Research Student Conference: Book of Abstracts

The fourth SED Research Student Conference (ReSCon2011) was hosted over three days, 20-22 June 2011, in the Hamilton Centre at Brunel University. The conference consisted of technical presentations, a poster session and social events. which focused on current research being conducted within the School of Engineering and Design by postgraduate research students from the School. The conference is held annually, and ReSCon plays a key role in contributing to research and innovations within the School

Monitoring Bacteria Cultures Using Near Infrared (nir) Binary Spectronephelometry (bsn), Raman Spectra and Principal Component Analysis (pca)

Current noninvasive methods cannot continuously and simultaneously monitor the concentrations of cells and media components that define the state of native bacterial cultures, because of changing turbidity. A new technique, binary spectronephelometry (BSN) has the same or better sensitivity and precision for population monitoring as optical density at 600nm (OD600), while simultaneously measuring metabolic processes. The BSN algorithm uses laser induced emission to probe mildly turbid media i.e., propagation of light occurs in the single scattering regime. A BSN training set associates a grid of elastic emission measurements, comprising Rayleigh and Mie scattering, and inelastic emission measurements, comprising fluorescence and Raman emission, with a grid of varying known concentrations of bacteria and media. For the normal lifecycle culture and for some but not all growth media, the results confirmed the linear dependence of the two measured signals on the concentration of bacteria and medium dilutions, and agreement with OD600. Having thus confirmed basic assumptions and a calibrated algorithm, various bacteria cultures were monitored over time, producing quantitative growth curves for the bacteria and depletion curves for media. Simultaneously obtained Raman spectra demonstrate glucose uptake and conversion into bacterial membrane phospholipids. Beyond the normal life cycle, a few examples of using BSN to monitor cultures subjected to external perturbations are shown. Specific characteristics of Principal Component Analysis (PCA) of Raman spectra, and their variation in bacterial cultures, as well as assessing the role of bacterial transport e.g., diffusion in performing and analyzing BSN, are presented

From wearable towards epidermal computing : soft wearable devices for rich interaction on the skin

Human skin provides a large, always available, and easy to access real-estate for interaction. Recent advances in new materials, electronics, and human-computer interaction have led to the emergence of electronic devices that reside directly on the user's skin. These conformal devices, referred to as Epidermal Devices, have mechanical properties compatible with human skin: they are very thin, often thinner than human hair; they elastically deform when the body is moving, and stretch with the user's skin. Firstly, this thesis provides a conceptual understanding of Epidermal Devices in the HCI literature. We compare and contrast them with other technical approaches that enable novel on-skin interactions. Then, through a multi-disciplinary analysis of Epidermal Devices, we identify the design goals and challenges that need to be addressed for advancing this emerging research area in HCI. Following this, our fundamental empirical research investigated how epidermal devices of different rigidity levels affect passive and active tactile perception. Generally, a correlation was found between the device rigidity and tactile sensitivity thresholds as well as roughness discrimination ability. Based on these findings, we derive design recommendations for realizing epidermal devices. Secondly, this thesis contributes novel Epidermal Devices that enable rich on-body interaction. SkinMarks contributes to the fabrication and design of novel Epidermal Devices that are highly skin-conformal and enable touch, squeeze, and bend sensing with co-located visual output. These devices can be deployed on highly challenging body locations, enabling novel interaction techniques and expanding the design space of on-body interaction. Multi-Touch Skin enables high-resolution multi-touch input on the body. We present the first non-rectangular and high-resolution multi-touch sensor overlays for use on skin and introduce a design tool that generates such sensors in custom shapes and sizes. Empirical results from two technical evaluations confirm that the sensor achieves a high signal-to-noise ratio on the body under various grounding conditions and has a high spatial accuracy even when subjected to strong deformations. Thirdly, Epidermal Devices are in contact with the skin, they offer opportunities for sensing rich physiological signals from the body. To leverage this unique property, this thesis presents rapid fabrication and computational design techniques for realizing Multi-Modal Epidermal Devices that can measure multiple physiological signals from the human body. Devices fabricated through these techniques can measure ECG (Electrocardiogram), EMG (Electromyogram), and EDA (Electro-Dermal Activity). We also contribute a computational design and optimization method based on underlying human anatomical models to create optimized device designs that provide an optimal trade-off between physiological signal acquisition capability and device size. The graphical tool allows for easily specifying design preferences and to visually analyze the generated designs in real-time, enabling designer-in-the-loop optimization. Experimental results show high quantitative agreement between the prediction of the optimizer and experimentally collected physiological data. Finally, taking a multi-disciplinary perspective, we outline the roadmap for future research in this area by highlighting the next important steps, opportunities, and challenges. Taken together, this thesis contributes towards a holistic understanding of Epidermal Devices}: it provides an empirical and conceptual understanding as well as technical insights through contributions in DIY (Do-It-Yourself), rapid fabrication, and computational design techniques.Die menschliche Haut bietet eine große, stets verfügbare und leicht zugängliche Fläche für Interaktion. Jüngste Fortschritte in den Bereichen Materialwissenschaft, Elektronik und Mensch-Computer-Interaktion (Human-Computer-Interaction, HCI) [so that you can later use the Englisch abbreviation] haben zur Entwicklung elektronischer Geräte geführt, die sich direkt auf der Haut des Benutzers befinden. Diese sogenannten Epidermisgeräte haben mechanische Eigenschaften, die mit der menschlichen Haut kompatibel sind: Sie sind sehr dünn, oft dünner als ein menschliches Haar; sie verformen sich elastisch, wenn sich der Körper bewegt, und dehnen sich mit der Haut des Benutzers. Diese Thesis bietet, erstens, ein konzeptionelles Verständnis von Epidermisgeräten in der HCI-Literatur. Wir vergleichen sie mit anderen technischen Ansätzen, die neuartige Interaktionen auf der Haut ermöglichen. Dann identifizieren wir durch eine multidisziplinäre Analyse von Epidermisgeräten die Designziele und Herausforderungen, die angegangen werden müssen, um diesen aufstrebenden Forschungsbereich voranzubringen. Im Anschluss daran untersuchten wir in unserer empirischen Grundlagenforschung, wie epidermale Geräte unterschiedlicher Steifigkeit die passive und aktive taktile Wahrnehmung beeinflussen. Im Allgemeinen wurde eine Korrelation zwischen der Steifigkeit des Geräts und den taktilen Empfindlichkeitsschwellen sowie der Fähigkeit zur Rauheitsunterscheidung festgestellt. Basierend auf diesen Ergebnissen leiten wir Designempfehlungen für die Realisierung epidermaler Geräte ab. Zweitens trägt diese Thesis zu neuartigen Epidermisgeräten bei, die eine reichhaltige Interaktion am Körper ermöglichen. SkinMarks trägt zur Herstellung und zum Design neuartiger Epidermisgeräte bei, die hochgradig an die Haut angepasst sind und Berührungs-, Quetsch- und Biegesensoren mit gleichzeitiger visueller Ausgabe ermöglichen. Diese Geräte können an sehr schwierigen Körperstellen eingesetzt werden, ermöglichen neuartige Interaktionstechniken und erweitern den Designraum für die Interaktion am Körper. Multi-Touch Skin ermöglicht hochauflösende Multi-Touch-Eingaben am Körper. Wir präsentieren die ersten nicht-rechteckigen und hochauflösenden Multi-Touch-Sensor-Overlays zur Verwendung auf der Haut und stellen ein Design-Tool vor, das solche Sensoren in benutzerdefinierten Formen und Größen erzeugt. Empirische Ergebnisse aus zwei technischen Evaluierungen bestätigen, dass der Sensor auf dem Körper unter verschiedenen Bedingungen ein hohes Signal-Rausch-Verhältnis erreicht und eine hohe räumliche Auflösung aufweist, selbst wenn er starken Verformungen ausgesetzt ist. Drittens, da Epidermisgeräte in Kontakt mit der Haut stehen, bieten sie die Möglichkeit, reichhaltige physiologische Signale des Körpers zu erfassen. Um diese einzigartige Eigenschaft zu nutzen, werden in dieser Arbeit Techniken zur schnellen Herstellung und zum computergestützten Design von multimodalen Epidermisgeräten vorgestellt, die mehrere physiologische Signale des menschlichen Körpers messen können. Die mit diesen Techniken hergestellten Geräte können EKG (Elektrokardiogramm), EMG (Elektromyogramm) und EDA (elektrodermale Aktivität) messen. Darüber hinaus stellen wir eine computergestützte Design- und Optimierungsmethode vor, die auf den zugrunde liegenden anatomischen Modellen des Menschen basiert, um optimierte Gerätedesigns zu erstellen. Diese Designs bieten einen optimalen Kompromiss zwischen der Fähigkeit zur Erfassung physiologischer Signale und der Größe des Geräts. Das grafische Tool ermöglicht die einfache Festlegung von Designpräferenzen und die visuelle Analyse der generierten Designs in Echtzeit, was eine Optimierung durch den Designer im laufenden Betrieb ermöglicht. Experimentelle Ergebnisse zeigen eine hohe quantitative Übereinstimmung zwischen den Vorhersagen des Optimierers und den experimentell erfassten physiologischen Daten. Schließlich skizzieren wir aus einer multidisziplinären Perspektive einen Fahrplan für zukünftige Forschung in diesem Bereich, indem wir die nächsten wichtigen Schritte, Möglichkeiten und Herausforderungen hervorheben. Insgesamt trägt diese Arbeit zu einem ganzheitlichen Verständnis von Epidermisgeräten bei: Sie liefert ein empirisches und konzeptionelles Verständnis sowie technische Einblicke durch Beiträge zu DIY (Do-It-Yourself), schneller Fertigung und computergestützten Entwurfstechniken

Design of an acoustically transparent pressure sensor for breast elastography

Breast cancer is the most commonly occurring cancer in women. Only in 2018 there were over 2 million new cases all over the world. The MURAB project, pursued at the University of Twente, has the aim to improving the breast biopsy procedure by reducing costs, patient discomfort and false negative rates. A 7-DOF KUKA robot arm steers an ultrasound transducer along a precise scanning trajectory to gather 3D volume image and stiffness values of the breast. Elasticity is the property of a body to be deformed and differs between tumors tissue and soft tissue. Elastography is a non-invasive technique in which the elasticity of a tissue is determined. The aim of this study is to design an acoustically transparent pressure sensor, mounted on the tip of the ultrasound probe, that can measure pressure differences across its surface during the scan, and assess elastographic measurements. The main idea is to use a pad of a characterized material and sequentially ultrasound images able to visualize the section of the pad and evaluate its deformation during time. The transmission of ultrasound waves into a solid depends on the mechanical characteristics of the material and on its physic state. In this work the relations between the acoustic properties and the mechanical behavior of an acoustically transparent pad are studied and evaluated

PROCESSING OF PIEZOELECTRIC OXIDE FILMS FOR SURFACE HAPTICS

Human-machine interaction (HMI) relies mainly on vision and hearing, but touch is essential for perceiving the environment, especially for those who are visually impaired. To incorporate touch into HMI systems, haptic technologies have been developed, with piezoelectric actuators being a promising solution. However, challenges exist in integrating these actuators into touch screens due to their thickness and lack of transparency. Researchers have turned to piezoelectric PZT thin films that provide acceptable haptic performance and optical transparency. Depositing these films onto glass substrates presents challenges, requiring a low-temperature process to enable cost-effective and large-scale production. Transparent electrodes, particularly indium tin oxide, are necessary for creating transparent actuators, but their production process is complex and costly. Chemical solution deposition (CSD) based on inkjet printing technology is a low-cost and largescale deposition method, enabling direct film patterning without expensive lithography. In this thesis these challenges were addressed by developing a low-temperature flash-lamp process for PZT film growth, low-temperature combustion processed and inkjet printed ITO electrodes, and an all inkjet printed haptic device. Additionally, we proposed the use of thick piezoelectric films for low-power consumption and large deflection in haptic applications that do not require transparency.R-AGR-3444 - PRIDE17/12246511 PACE_Common (01/03/2019 - 31/08/2025) - DALE Phillip9. Industry, innovation and infrastructur

Aligned Silver Nanowire Networks as Transparent Electrodes for High-Performance Optoelectronics and Electronic Devices

Department of Energy EngineeringFlexible transparent electrode is an essential component for several kinds of electronic and optoelectronic applications, such as organic solar cells (OSCs), perovskite solar cells (PSCs), organic light-emitting diodes (OLEDs), touch sensors, and electronic skins (E-skins). Although conventional indium tin oxide (ITO) has been widely used in commercial transparent electrodes, it still shows a limitation in the fabrication of flexible transparent electrodes for applications in flexible/wearable electronic devices because of their inherent brittleness. Among various alternatives of ITO, silver nanowire (AgNW) network has been considered as promising conductive nano-material due to their high electrical conductivity, excellent transmittance, and mechanical flexibility that can be readily deposited by cost-effective and large-scale solution process. However, random AgNW networks prepared by solution processing have several drawbacks, such as high junction resistance between nanowires (NWs), low transmittance, haze issues, and rough surface morphologies, resulting in a degradation of the device performance. Electrical and optical properties of random AgNW networks can be strongly affected by controlling NW density, electrical current path, and junction resistance related to conductive percolated networks. Therefore, manipulating the assembled structure of AgNW network can provide powerful platforms to realize ideal flexible transparent electrodes with high electrical conductivity, superior transmittance, and smooth surface morphologies for achieving high-performance electronic and optoelectronic device. In this thesis, we introduce aligned AgNW transparent electrodes and their applications in flexible optoelectronic and functional electronic devices. Firstly, Chapter 1 introduces the research tends in transparent electrodes and several issues of AgNW networks that should be carefully considered in the fabrication for their potential device applications. In chapter 2, we demonstrate the capillary printing technique to make highly aligned AgNW network to fabricate high-performance transparent electrodes for improving device efficiency of optoelectronic devices including OSCs and OLEDs. In Chapter 3, we demonstrate the fabrication of nanoparticle (NP)-enhanced plasmonic AgNW electrode for high-performance optoelectronic devices in which the NP-NW hybrid plasmonic system generates gap plasmonic coupling which induces a large electric field enhancement, resulting in an improvement of the device efficiency in both OSC and OLED devices. In Chapter 4, we demonstrate the fabrication of ultrathin and flexible perovskite solar cell foils with orthogonal AgNW electrodes, which exhibits high power-per-weight performance as well as a conformal contact capability to curvilinear surface. In Chapter 5, we introduce a large-scale assembly technique to uniformly align AgNW arrays for the fabrication of large area transparent electrodes, where cross-aligned AgNW network shows better electrical and optical properties as well as large-scale uniformity than random AgNW network. For the proof of the concept demonstration, we fabricated a flexible force-sensitive touch screen panel integrated with a mechanochromic polymer film. Finally, we introduce a transparent and conductive nano-membrane (NM) incorporated with orthogonal AgNW arrays in Chapter 6, which exhibits enhanced electrical and mechanical properties than pure polymeric NMs. To show the unique properties of these hybrid NMs for potential device applications, we demonstrate skin-attachable thermoacoustic-based NM loudspeaker and wearable NM microphone, both of which show much improved device performances compared to conventional thin film-based devices. In this thesis, studies on aligned AgNW transparent electrodes and their device applications could be further expanded for diverse flexible and wearable optoelectronic and electronic applications, such as conformal wearable sensors, healthcare monitoring devices, and wearable plasmonic devices.clos

Workshop on "Control issues in the micro / nano - world".

International audienceDuring the last decade, the need of systems with micro/nanometers accuracy and fast dynamics has been growing rapidly. Such systems occur in applications including 1) micromanipulation of biological cells, 2) micrassembly of MEMS/MOEMS, 3) micro/nanosensors for environmental monitoring, 4) nanometer resolution imaging and metrology (AFM and SEM). The scale and requirement of such systems present a number of challenges to the control system design that will be addressed in this workshop. Working in the micro/nano-world involves displacements from nanometers to tens of microns. Because of this precision requirement, environmental conditions such as temperature, humidity, vibration, could generate noise and disturbance that are in the same range as the displacements of interest. The so-called smart materials, e.g., piezoceramics, magnetostrictive, shape memory, electroactive polymer, have been used for actuation or sensing in the micro/nano-world. They allow high resolution positioning as compared to hinges based systems. However, these materials exhibit hysteresis nonlinearity, and in the case of piezoelectric materials, drifts (called creep) in response to constant inputs In the case of oscillating micro/nano-structures (cantilever, tube), these nonlinearities and vibrations strongly decrease their performances. Many MEMS and NEMS applications involve gripping, feeding, or sorting, operations, where sensor feedback is necessary for their execution. Sensors that are readily available, e.g., interferometer, triangulation laser, and machine vision, are bulky and expensive. Sensors that are compact in size and convenient for packaging, e.g., strain gage, piezoceramic charge sensor, etc., have limited performance or robustness. To account for these difficulties, new control oriented techniques are emerging, such as[d the combination of two or more ‘packageable' sensors , the use of feedforward control technique which does not require sensors, and the use of robust controllers which account the sensor characteristics. The aim of this workshop is to provide a forum for specialists to present and overview the different approaches of control system design for the micro/nano-world and to initiate collaborations and joint projects