Shaping Event-Based Haptic Transients Via an Improved Understanding of Real Contact Dynamics

Haptic interactions with stiff virtual surfaces feel more realistic when a short-duration transient is added to the spring force at contact. But how should this event-based transient be shaped? To answer this question, we present a targeted user study on virtual surface realism that demonstrates the importance of scaling transients correctly and hints at the complexity of this dynamic relationship. We then present a detailed examination of the dynamics of tapping on a rigid surface with a hand-held probe; theoretical modeling is combined with empirical data to determine the influence of impact velocity, impact acceleration, and user grip force on the resulting transient surface force. The derived mathematical relationships provide a formula for generating open-loop, event-based force transients upon impact with a virtual surface. By incorporating an understanding of the dynamics of real interactions into the re-creation of virtual contact, these findings promise to improve the performance and realism of a wide range of haptic simulations

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

Progressive haptic guidance for a dynamic task in a virtual training environment

This thesis presents the motivation for and implementation of a novel progressive haptic guidance scheme designed to improve the efficiency of a virtual training environment used for skill acquisition. A detailed expertise-based analysis of the dynamic human motor task identifies the key skills required for success and motivates the progressive haptic guidance scheme. The thesis compares the effectiveness of the scheme to similar visual guidance, written guidance and no-guidance. The experimental training protocol presents a target-hitting training task in a virtual environment that utilizes an LCD display for visual feedback and a force feedback joystick for haptic interactions. This protocol lasts eleven sessions over a two-month period, thereby ensuring the performance saturation of participants. During each session, the number of target hits obtained becomes the objective measure of performance. Two additional measures, trajectory error and input frequency, are defined and implemented to calculate the performance of participants in two key skills. The guidance scheme then employs these last two measures as gain inputs to the guidance controller, which in turn progressively diminishes the forces that display guidance as virtual walls. The haptic controller design initially restricts a participant's motion to a preferred task path, but increased performance results in decreased guidance from one trial to the next. In addition to these measures, the protocol also presents the computerized version of the NASA Task Load Index (TLX) to all participants at each session, thereby providing cognitive workload measurements throughout the entire training period. The results demonstrate that this progressive haptic guidance scheme, one that integrates key skills and measures of performance, significantly outperforms three other guidance modes early on in the training and only when guidance is active. The data failed to show whether the haptic guidance scheme has significantly higher performance when the guidance is inactive. This scheme also generates less frustration and mental workload than visual guidance. Possible applications for these findings include virtual training environments designed for surgery and rehabilitation

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

Influence of contact conditions on thermal responses of the hand

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2009.Includes bibliographical references (leaves 82-87).The objective of the research conducted for this thesis was to evaluate the influence of contact conditions on the thermal responses of the finger pad and their perceptual effects. A series of experiments investigated the thermal and perceptual effects of different contact conditions including contact force, contact duration, the object's surface temperature, and its surface roughness. The thermal response of the finger pad was measured using an infrared camera as the contact force varied from 0.1 to 6 N. It was determined that the decrease in skin temperature was highly dependent on the magnitude of contact force as well as contact duration. A second set of experiments investigated the effect of surface texture on the thermal response of the finger pad, and demonstrated, contrary to predictions, that a greater change in skin temperature occurs when the finger is in contact with rougher surfaces. The effect of varying surface texture on the perception of temperature was also investigated. The changes in temperature due to varying surface texture are perceptible, and demonstrate that the perception of surface roughness is not only influenced by changes in temperature, but in turn affects the perception of temperature. The final set of experiments examined the effect of varying the surface temperature of the thermal display on the perceived magnitude of finger force. Over the range of 20 to 38 'C, the surface temperature of the display did not have a significant effect on the perceived magnitude of force. The results of these experiments can be incorporated into thermal models that are used to create more realistic displays for virtual environments and teleoperated systems.by Jessica Anne Galie.S.M

Realistic tool-tissue interaction models for surgical simulation and planning

Surgical simulators present a safe and potentially effective method for surgical training, and can also be used in pre- and intra-operative surgical planning. Realistic modeling of medical interventions involving tool-tissue interactions has been considered to be a key requirement in the development of high-fidelity simulators and planners. The soft-tissue constitutive laws, organ geometry and boundary conditions imposed by the connective tissues surrounding the organ, and the shape of the surgical tool interacting with the organ are some of the factors that govern the accuracy of medical intervention planning.\ud \ud This thesis is divided into three parts. First, we compare the accuracy of linear and nonlinear constitutive laws for tissue. An important consequence of nonlinear models is the Poynting effect, in which shearing of tissue results in normal force; this effect is not seen in a linear elastic model. The magnitude of the normal force for myocardial tissue is shown to be larger than the human contact force discrimination threshold. Further, in order to investigate and quantify the role of the Poynting effect on material discrimination, we perform a multidimensional scaling study. Second, we consider the effects of organ geometry and boundary constraints in needle path planning. Using medical images and tissue mechanical properties, we develop a model of the prostate and surrounding organs. We show that, for needle procedures such as biopsy or brachytherapy, organ geometry and boundary constraints have more impact on target motion than tissue material parameters. Finally, we investigate the effects surgical tool shape on the accuracy of medical intervention planning. We consider the specific case of robotic needle steering, in which asymmetry of a bevel-tip needle results in the needle naturally bending when it is inserted into soft tissue. We present an analytical and finite element (FE) model for the loads developed at the bevel tip during needle-tissue interaction. The analytical model explains trends observed in the experiments. We incorporated physical parameters (rupture toughness and nonlinear material elasticity) into the FE model that included both contact and cohesive zone models to simulate tissue cleavage. The model shows that the tip forces are sensitive to the rupture toughness. In order to model the mechanics of deflection of the needle, we use an energy-based formulation that incorporates tissue-specific parameters such as rupture toughness, nonlinear material elasticity, and interaction stiffness, and needle geometric and material properties. Simulation results follow similar trends (deflection and radius of curvature) to those observed in macroscopic experimental studies of a robot-driven needle interacting with gels

Computer-supported movement guidance: investigating visual/visuotactile guidance and informing the design of vibrotactile body-worn interfaces

This dissertation explores the use of interactive systems to support movement guidance, with applications in various fields such as sports, dance, physiotherapy, and immersive sketching. The research focuses on visual, haptic, and visuohaptic approaches and aims to overcome the limitations of traditional guidance methods, such as dependence on an expert and high costs for the novice. The main contributions of the thesis are (1) an evaluation of the suitability of various types of displays and visualizations of the human body for posture guidance, (2) an investigation into the influence of different viewpoints/perspectives, the addition of haptic feedback, and various movement properties on movement guidance in virtual environments, (3) an investigation into the effectiveness of visuotactile guidance for hand movements in a virtual environment, (4) two in-depth studies of haptic perception on the body to inform the design of wearable and handheld interfaces that leverage tactile output technologies, and (5) an investigation into new interaction techniques for tactile guidance of arm movements. The results of this research advance the state of the art in the field, provide design and implementation insights, and pave the way for new investigations in computer-supported movement guidance

”Haptic Processor Unit” : vers une Plate-Forme Transportable pour la Simulation Temps-Réel Synchrone Multisensorielle

This work is related to the field of Human-Computer Interaction, and particularly to the field of multisensory instrumental simulation, as conceptualized by the research group ACROE & ICA, and which needs a strong coupling between the human and the instrument.The first part of this thesis presents various degrees of the integration of gesture in computer uses, then develops a functional approach of force feedback technologies. This analysis elicits the mainstreams that are currently sharing the field of haptics research. We then present a study of the hardware and software components that are used in haptic simulation, and the various approaches used to connect a force feedback device to a real time modelling system. The analysis of the role of each of the components in the simulation chain and their relationships allowed us to conceptualize the “Haptic Processor Unit”. This component guarantees in particular the conditions of reactivity that are required for multisensory simulation. The new simulation architecture that we designed in this work, named ERGON_X, implements the concept of HPU. ERGON_X is a compact and transportable simulator, and handles simulation frequencies up to 44 100Hz. The third part presents the validation of the simulation platform ERGON_X. It mainly focuses on the design of new models, which were used in the framework of the research carried on by ACROE & ICA about instrumental interaction. The “E” is a model demonstrating the capabilities of the ERGOS technology, which is now fully exploitable thanks to this new simulation architecture. The models of tapping and of deformable paste allowed us to bring new results on human-object interaction, and validate the simulator as a tool for psychophysical experimentation. The Enactive Emblematic Scenarii “Ergotic Sounds” and “Pebble Box” illustrate the conception of Enaction. They validate the use of our simulation architecture as an experimental platform and lead us to a paradigm shift from “instrumental interaction” to “enactive interaction”Ce travail se situe dans le domaine de l’Interaction Personne-Système, et plus particulièrement dans celui de la simulation instrumentale multisensorielle telle que conceptualisée par le groupe de recherche ACROE & ICA, qui nécessite un couplage fort homme-instrument.La première partie de cette thèse présente les différents degrés d’intégration du geste dans l’ordinateur, puis propose une approche fonctionnelle des technologies pour le retour d’effort. Nous dégageons de cette analyse les grandes approches qui se partagent actuellement le champ de la recherche « haptique ».Nous présentons ensuite une étude sur les différents composants matériels et logiciels nécessaires à la chaîne de simulation haptique, ainsi que les différentes approches utilisées pour connecter un système à retour d’effort à un processus de simulation en temps réel. L’analyse du rôle des composants de la chaîne de simulation et de leurs relations permet de formaliser le concept de « Haptic Processor Unit ». Ce composant permet en particulier de garantir les conditions de réactivité propres à la simulation multisensorielle. La nouvelle architecture de simulation multisensorielle que nous avons réalisée, ERGON_X, met en œuvre le concept de HPU.ERGON_X est un simulateur compact et transportable, et permet d’utiliser des fréquences de simulation jusqu’à 44 100Hz. La dernière partie présente la validation de la plate-forme de simulation ERGON_X. Elle est essentiellement orientée vers l’implantation de nouveaux modèles, utilisés dans le cadre d’un travail de recherche sur la situation instrumentale médiatisée. Le « E » est un modèle de démonstration des performances de la technologie ERGOS que la nouvelle architecture de simulation permet d’exploiter pleinement. Les modèles de tapping (percussion) et de pâtes déformables ont permis d’avancer des résultatssur l’interaction homme-objet, et valident le simulateur comme un outil pour l’expérimentation psychophysique. Les Enactive Emblematic Scenarii « Ergotic Sounds » (frottement d’archet) et « Pebble Box » (la boîte à cailloux) sont des illustrations du concept de l’Enaction. Elles valident l’utilisation de l’architecture de simulation comme une plate-forme pour l’expérimentation et ouvrent de nouvelles perspectives de recherche sur l’enaction et la notion de présence en simulation interactive