Using Stick-Slip to provide directional forces and kinesthetic feedback on interactive display surfaces

Modern interactive surfaces and displays provide powerful and highly efficient visual and auditory human-computer interfaces. However, the usage of haptics is still in its infancy. Often limited to primitive vibrotactile warning or notification signals, the possibilities of haptics to communicate complex images and information have not yet been realized. Based on research done in previous years, new methods have been developed to deliver more specific tactile information about objects and their surfaces. Nevertheless, the kinesthetic sense, which enables to detect different object properties such as weight, inertia and impedance, is rarely discussed as a part of a haptic system. Relying on kinesthetic information has been proven to be beneficial in order to detect, recognize and interpret haptic images in the virtual world. This has been achieved by using linkage-based multi-dimensional manipulators, exoskeletons or robotic arms. Based on the increased usage of mobile devices, new challenges are arising, especially considering linkage-free technologies. To approach this challenge, this thesis describes a system which is able to apply directional forces, linkage-free to a stylus tip, in order to control user behavior. The stick-slip phenomenon has been used as the basic technique to deliver directional forces in the absence of kinematic chains and mechanical linkages. Based on the theoretical approach, the prototype requirements were specified and the configuration of the system (mechanical components, actuators and control parameters) were discussed. By using the resulting system specification, three mockups were developed which led to a final system implementation. During the course of this research, it was demonstrated that it is possible to generate directional forces on an interactive display in order to move a stylus linkage-free over the touchscreen in a fully controlled and efficient manner. The technology described in this thesis opens new possibilities for interacting with displays. The developed system can be used to provide continuously-supervised learning or feed forward systems which predict the user behavior and modify kinesthetic signals

Multisensory texture exploration at the tip of the pen

A tool for the multisensory stylus-based exploration of virtual textures was used to investigate how different feedback modalities (static or dynamically deformed images, vibration, sound) affect exploratory gestures. To this end, we ran an experiment where participants had to steer a path with the stylus through a curved corridor on the surface of a graphic tablet/display, and we measured steering time, dispersion of trajectories, and applied force. Despite the variety of subjective impressions elicited by the different feedback conditions, we found that only nonvisual feedback induced significant variations in trajectories and an increase in movement time. In a post-experiment, using a paper-and-wood physical realization of the same texture, we recorded a variety of gestural behaviors markedly different from those found with the virtual texture. With the physical setup, movement time was shorter and texture-dependent lateral accelerations could be observed. This work highlights the limits of multisensory pseudo-haptic techniques in the exploration of surface textures

Wearable haptic systems for the fingertip and the hand: taxonomy, review and perspectives

In the last decade, we have witnessed a drastic change in the form factor of audio and vision technologies, from heavy and grounded machines to lightweight devices that naturally fit our bodies. However, only recently, haptic systems have started to be designed with wearability in mind. The wearability of haptic systems enables novel forms of communication, cooperation, and integration between humans and machines. Wearable haptic interfaces are capable of communicating with the human wearers during their interaction with the environment they share, in a natural and yet private way. This paper presents a taxonomy and review of wearable haptic systems for the fingertip and the hand, focusing on those systems directly addressing wearability challenges. The paper also discusses the main technological and design challenges for the development of wearable haptic interfaces, and it reports on the future perspectives of the field. Finally, the paper includes two tables summarizing the characteristics and features of the most representative wearable haptic systems for the fingertip and the hand

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

Multilayer haptic feedback for pen-based tablet interaction

We present a novel, multilayer interaction approach that enables state transitions between spatially above-screen and 2D on-screen feedback layers. This approach supports the exploration of haptic features that are hard to simulate using rigid 2D screens. We accomplish this by adding a haptic layer above the screen that can be actuated and interacted with (pressed on) while the user interacts with on-screen content using pen input. The haptic layer provides variable firmness and contour feedback, while its membrane functionality affords additional tactile cues like texture feedback. Through two user studies, we look at how users can use the layer in haptic exploration tasks, showing that users can discriminate well between different firmness levels, and can perceive object contour characteristics. Demonstrated also through an art application, the results show the potential of multilayer feedback to extend on-screen feedback with additional widget, tool and surface properties, and for user guidance

RealPen: Providing Realism in Handwriting Tasks on Touch Surfaces using Auditory-Tactile Feedback

We present RealPen, an augmented stylus for capacitive tablet screens that recreates the physical sensation of writing on paper with a pencil, ball-point pen or marker pen. The aim is to create a more engaging experience when writing on touch surfaces, such as screens of tablet computers. This is achieved by regenerating the friction-induced oscillation and sound of a real writing tool in contact with paper. To generate realistic tactile feedback, our algorithm analyzes the frequency spectrum of the friction oscillation generated when writing with traditional tools, extracts principal frequencies, and uses the actuator's frequency response profile for an adjustment weighting function. We enhance the realism by providing the sound feedback aligned with the writing pressure and speed. Furthermore, we investigated the effects of superposition and fluctuation of several frequencies on human tactile perception, evaluated the performance of RealPen, and characterized users' perception and preference of each feedback type

Determining the Haptic Feedback Position for Optimizing the Targeting Performance on Ultrasonic Tactile Displays

International audienceAlongside questions of how to create haptic effects on displays via alternative hardware, recent work has explored rendering options with respect to haptic effects, i.e. when and where to provide haptic feedback. In particular, recent work by Zhang and Harrison for electrostatic haptic feedback noted that the optimal technique for haptic feedback during interaction is the Fill technique, where haptic effects are rendered at all times when a user's finger is within the bounds of the target. In this paper, we explore whether this result generalizes to an alternative haptic rendering technology that uses ultrasonic vibrations to create haptic sensations, a technique called the " Squeeze Film Effect ". In contrast to prior work, our results indicate that positioning the haptic feedback as a discrete linear stimulus centred on the target provides an optimal trade-off between speed, accuracy, and user preference. We highlight the implications of this work to the generalizability of haptic feedback: Haptic feedback can improve time, errors, and user satisfaction during interaction, but only if the correct form of feedback is used for the specific haptic effect generated by the hardware

Remote tactile feedback on interactive surfaces

Direct touch input on interactive surfaces has become a predominating standard for the manipulation of digital information in our everyday lives. However, compared to our rich interchange with the physical world, the interaction with touch-based systems is limited in terms of flexibility of input and expressiveness of output. Particularly, the lack of tactile feedback greatly reduces the general usability of a touch-based system and hinders from a productive entanglement of the virtual information with the physical world. This thesis proposes remote tactile feedback as a novel method to provide programmed tactile stimuli supporting direct touch interactions. The overall principle is to spatially decouple the location of touch input (e.g. fingertip or hand) and the location of the tactile sensation on the user's body (e.g. forearm or back). Remote tactile feedback is an alternative concept which avoids particular challenges of existing approaches. Moreover, the principle provides inherent characteristics which can accommodate for the requirements of current and future touch interfaces. To define the design space, the thesis provides a structured overview of current forms of touch surfaces and identifies trends towards non-planar and non-rigid forms with more versatile input mechanisms. Furthermore, a classification highlights limitations of the current methods to generate tactile feedback on touch-based systems. The proposed notion of tactile sensory relocation is a form of sensory substitution. Underlying neurological and psychological principles corroborate the approach. Thus, characteristics of the human sense of touch and principles from sensory substitution help to create a technical and conceptual framework for remote tactile feedback. Three consecutive user studies measure and compare the effects of both direct and remote tactile feedback on the performance and the subjective ratings of the user. Furthermore, the experiments investigate different body locations for the application of tactile stimuli. The results show high subjective preferences for tactile feedback, regardless of its type of application. Additionally, the data reveals no significant differences between the effects of direct and remote stimuli. The results back the feasibility of the approach and provide parameters for the design of stimuli and the effective use of the concept. The main part of the thesis describes the systematical exploration and analysis of the inherent characteristics of remote tactile feedback. Four specific features of the principle are identified: (1) the simplification of the integration of cutaneous stimuli, (2) the transmission of proactive, reactive and detached feedback, (3) the increased expressiveness of tactile sensations and (4) the provision of tactile feedback during multi-touch. In each class, several prototypical remote tactile interfaces are used in evaluations to analyze the concept. For example, the PhantomStation utilizes psychophysical phenomena to reduce the number of single tactile actuators. An evaluation with the prototype compares standard actuator technologies with each other in order to enable simple and scalable implementations. The ThermalTouch prototype creates remote thermal stimuli to reproduce material characteristics on standard touchscreens. The results show a stable rate of virtual object discrimination based on remotely applied temperature profiles. The AutmotiveRTF system is implemented in a vehicle and supports the driver's input on the in-vehicle-infotainment system. A field study with the system focuses on evaluating the effects of proactive and reactive feedback on the user's performance. The main contributions of the dissertation are: First, the thesis introduces the principle of remote tactile feedback and defines a design space for this approach as an alternative method to provide non-visual cues on interactive surfaces. Second, the thesis describes technical examples to rapidly prototype remote tactile feedback systems. Third, these prototypes are deployed in several evaluations which highlight the beneficial subjective and objective effects of the approach. Finally, the thesis presents features and inherent characteristics of remote tactile feedback as a means to support the interaction on today's touchscreens and future interactive surfaces.Die Interaktion mit berührungsempfindlichen Oberflächen ist heute ein Standard für die Manipulation von digitaler Information. Jedoch weist die Bedienung dieser interaktiven Bildschirme starke Einschränkungen hinsichtlich der Flexibilität bei der Eingabe und der Ausdruckskraft der Ausgabe auf, wenn man sie mit den vielfältigen Möglichkeiten des Umgangs mit Objekten in unserer Alltagswelt vergleicht. Besonders die nicht vorhandenen Tastsinnesrückmeldungen vermindern stark die Benutzbarkeit solcher Systeme und verhindern eine effektive Verknüpfung von virtueller Information und physischer Welt. Die vorliegende Dissertation beschreibt den Ansatz der 'distalen taktilen Rückmeldungen' als neuartige Möglichkeit zur Vermittlung programmierter Tastsinnesreize an Benutzer interaktiver Oberflächen. Das Grundprinzip dabei ist die räumliche Trennung zwischen der Eingabe durch Berührung (z.B. mit der Fingerspitze) und dem daraus resultierenden taktilen Reiz am Körper der Benutzer (z.B. am Rücken). Dabei vermeidet das Konzept der distalen taktilen Rückmeldungen einzelne technische und konzeptionelle Nachteile existierender Ansätze. Zusätzlich bringt es Interaktionsmöglichkeiten mit sich, die den Eigenheiten der Interaktion mit aktuellen und auch zukünftigen berührungsempfindlichen Oberflächen Rechnung tragen. Zu Beginn zeigt ein Überblick zu relevanten Arbeiten den aktuellen Forschungstrend hin zu nicht-flachen und verformbaren berührungsempfindlichen Oberflächen sowie zu vielfältigeren Eingabemethoden. Eine Klassifizierung ordnet existierende technische Verfahren zur Erzeugung von künstlichen Tastsinnesreizen und stellt jeweils konzeptuelle und technische Herausforderungen dar. Der in dieser Arbeit vorgeschlagene Ansatz der Verlagerung von Tastsinnesreizen ist eine Form der sensorischen Substitution, zugrunde liegende neurologische und psychologische Prinzipien untermauern das Vorgehen. Die Wirkprinzipien des menschlichen Tastsinnes und die Systeme zur sensorischen Substitution liefern daher konzeptionelle und technische Richtlinien zur Umsetzung der distalen taktilen Rückmeldungen. Drei aufeinander aufbauende Benutzerstudien vergleichen die Auswirkungen von direkten und distalen taktilen Rückmeldungen auf die Leistung und das Verhalten von Benutzern sowie deren subjektive Bewertung der Interaktion. Außerdem werden in den Experimenten die Effekte von Tastsinnesreizen an verschiedenen Körperstellen untersucht. Die Ergebnisse zeigen starke Präferenzen für Tastsinnesrückmeldungen, unabhängig von deren Applikationsort. Die Daten ergeben weiterhin keine signifikanten Unterschiede bei den quantitativen Effekten von direktem und distalen Rückmeldungen. Diese Ergebnisse befürworten die Realisierbarkeit des Ansatzes und zeigen Richtlinien für weitere praktische Umsetzungen auf. Der Hauptteil der Dissertation beschreibt die systematische Untersuchung und Analyse der inhärenten Möglichkeiten, die sich aus der Vermittlung distaler taktiler Rückmeldungen ergeben. Vier verschiedene Charakteristika werden identifiziert: (1) die vereinfachte Integration von Tastsinnesreizen, (2) die Vermittlung von proaktiven, reaktiven und entkoppelten Rückmeldungen, (3) die erhöhte Bandbreite der taktilen Signale und (4) die Darstellung von individuellen Tastsinnesreizen für verschiedene Kontaktpunkte mit der berührungsempfindlichen Oberfläche. Jedes dieser Prinzipien wird durch prototypische Systeme umgesetzt und in Benutzerstudien analysiert. Beispielsweise nutzt das System PhantomStation psychophysikalische Illusionen, um die Anzahl der einzelnen Reizgeber zu reduzieren. In einer Evaluierung des Prototypen werden mehrere Aktuatortechnologien verglichen, um einfache und skalierbare Ansätze zu identifizieren. Der ThermalTouch-Prototyp wird dazu genutzt, distale thermale Reize zu vermitteln, um so Materialeigenschaften auf Berührungsbildschirmen darstellen zu können. Eine Benutzerstudie zeigt, dass sich auf Basis dieser Temperaturverläufe virtuelle Objekte unterscheiden lassen. Das AutomotiveRTF-System wird schließlich in ein Kraftfahrzeug integriert, um den Fahrer bei der Eingabe auf dem Informations- und Unterhaltungssystem zu unterstützen. Eine Feldstudie untersucht die Auswirkungen der proaktiven und reaktiven Rückmeldungen auf die Benutzerleistung. Die vorliegende Dissertation leistet mehrere Beiträge zur Mensch-Maschine-Interaktion: Das Prinzip der distalen taktilen Rückmeldungen wird eingeführt als Alternative zur Erzeugung nicht-visueller Rückmeldungen auf interaktiven Oberflächen. Es werden technische Verfahrensweisen zur prototypischen Implementierung solcher Systeme vorgeschlagen. Diese technischen Prototypen werden in einer Vielzahl verschiedener Benutzerstudien eingesetzt, welche die quantitativen und qualitativen Vorteile des Ansatzes aufzeigen. Schließlich wird gezeigt, wie sich das Prinzip zur Unterstützung heutiger und zukünftiger Interaktionsformen mit berührungsempfindlichen Bildschirmen nutzen lässt