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## Über dieses Buch

The two-volume set LNCS 8618 and 8619 constitutes the refereed proceedings of the 9th International Conference EuroHaptics 2014, held in Versailles, France, in June 2014.
The 118 papers (36 oral presentations and 82 poster presentations) presented were carefully reviewed and selected from 183 submissions. Furthermore, 27 demos were exhibited, each of them resulting in a short paper included in the volumes. These proceedings reflect the multidisciplinary nature of EuroHaptics and cover topics such as human-computer interaction, human-robot interactions, neuroscience, perception and psychophysics, biomechanics and motor control, modelling and simulation; and a broad range of applications in medicine, rehabilitation, art, and design.

## Inhaltsverzeichnis

### Erratum to: Performance Evaluation of a Surgical Telerobotic System Using Kinematic Indices of the Master Hand-Controller

Yaser Maddahi, Michael Greene, Liu Shi Gan, Tomas Hirmer, Rachael L’Orsa, Sanju Lama, Garnette Roy Sutherland, Kourosh Zareinia

### Experimental Validation of a Rapid, Adaptive Robotic Assessment of the MCP Joint Angle Difference Threshold

This paper presents an experimental evaluation of a rapid, adaptive assessment of the difference threshold (DL) of passive metacarpophalangeal index finger joint flexion using a robotic device. Parameter Estimation by Sequential Testing (PEST) is compared to the method of constant stimuli (MOCS) using a two-alternative forced-choice paradigm. The pilot study with

$$13$$

healthy subjects provided DLs within similar ranges for MOCS and PEST, averaging at

$$2.15^{\circ }\pm 0.77^{\circ }$$

and

$$1.73^{\circ }\pm 0.78^{\circ }$$

, respectively, in accordance with the literature. However, no significant correlation was found between the two methods (

$$r(11) = 0.09$$

,

$$p = 0.762$$

). The average number of trials required for PEST to converge was

$$58.7\pm 17.6$$

, and significantly lower compared to

$$120$$

trials for MOCS (

$$p < 0.001$$

), leading to an assessment time of under

$$15$$

min. These results suggest that rapid, adaptive methods, such as PEST, could be successfully implemented in novel robotic tools for clinical assessment of sensory deficits.

Mike D. Rinderknecht, Werner L. Popp, Olivier Lambercy, Roger Gassert

### Friction Sensation Produced by Laterally Asymmetric Vibrotactile Stimulus

Vibrotactile texture stimuli have commonly been used to produce sensations of roughness. The extension of such stimuli to other textural modalities enhances their applicability. We found that laterally asymmetric vibrotactile stimuli cause a sensation of friction rather than vibration. When a vibrotactile contactor moves in one direction, it sticks to the finger pad and induces lateral skin stretch. In contrast, when the contactor moves in the other direction, it slips because of its quick motion and induces little skin stretch. As a result, humans experience frictional sensations in scanning vibrating contactors with their fingertips. We examined participants’ subjective responses and measured interactive forces between the finger pad and the contactor. Both perceptual and physical experiments corroborated the hypothesis of the production of a sensation of friction. Laterally asymmetric vibrotactile stimuli increased stretching of the finger pad skin and increased the sensation of friction.

Akihiro Imaizumi, Shogo Okamoto, Yoji Yamada

### Enhancing the Simulation of Boundaries by Coupling Tactile and Kinesthetic Feedback

Haptic enhanced boundaries are important for touch interaction. We quantify the amount of perceived force increment caused by adding variable friction tactile feedback to force feedback in simulating a boundary. We find that using a small lateral force feedback plus a tactile feedback can simulate a boundary which feels as stiff as that simulated by a large lateral force feedback. Moreover, the effect of the tactile feedback may be explained as a lateral force increment caused by increasing the friction coefficient of the touch surface.

Yi Yang, Yuru Zhang, Betty Lemaire-Semail, Xiaowei Dai

### Find the Missing Element! Haptic Identification of Incomplete Pictures by Sighted and Visually Impaired Children

This study investigates the haptic identification of incomplete raised-line drawings (i.e., pictures with a missing element) by sighted and early visually impaired children aged 9–10 years. Incomplete pictures have already been used in the visual modality to assess perceptual reasoning in children, but not yet under the haptic modality. We found that success at identifying incomplete raised-line pictures (correct naming of object plus missing feature) concerned 32.65 % of children’s responses, suggesting that the task was hard although not entirely impossible. Overall, the visually impaired children outperformed the sighted controls at this task. However, there was a large variation in responses across items, and the superiority of the visually impaired children over their sighted peers was not systematic. We concluded that adapting materials from the Wechsler’ image completion subtest to the haptic modality may be relevant to investigate haptic perceptual reasoning in children with and without visual impairments.

Anaïs Mazella, Jean-Michel Albaret, Delphine Picard

### The Haptic Analog of the Visual Aubert-Fleischl Phenomenon

In vision, the perceived velocity of a moving stimulus is different depending on whether the image moves across the retina with the eyes immobile or whether the observer pursues the stimulus such that the stimulus is stationary on the moving retina. The effect is known as the Aubert-Fleischl phenomenon. Here, we reproduced the analog of this visual illusion in haptics. For this purpose, we asked our participants to estimate the speed of a moving belt either from tactile cues, by keeping the hand world stationary, or from proprioceptive cues by tracking the belt with a guided upper-limb movement. The participants overestimated the speed of the moving stimulus determined from tactile cues compared with proprioceptive cues, in analogy with the Aubert-Fleischl phenomenon. Reproducing the illusion in the haptic modality may help evaluating some of the general mechanisms of spatial constancy in perceptual systems.

Alessando Moscatelli, Meike Scheller, Gabriele Joanna Kowalski, Marc Ernst

### Making Gestural Interaction Accessible to Visually Impaired People

As touch screens become widely spread, making them more accessible to visually impaired people is an important task. Touch displays possess a poor accessibility for visually impaired people. One possibility to make them more accessible without sight is through gestural interaction. Yet, there are still few studies on using gestural interaction for visually impaired people. In this paper we present a comprehensive summary of existing projects investigating accessible gestural interaction. We also highlight the limits of current approaches and propose future working directions. Then, we present the design of an interactive map prototype that includes both a raised-line map overlay and gestural interaction for accessing different types of information (e.g., opening hours, distances). Preliminary results of our project show that basic gestural interaction techniques can be successfully used in interactive maps for visually impaired people.

Anke Brock, Philippe Truillet, Bernard Oriola, Christophe Jouffrais

### Collaborative Pseudo-Haptics: Two-User Stiffness Discrimination Based on Visual Feedback

Pseudo-Haptic feedback has been the object of several studies exploring how haptic illusions can be generated when interacting with virtual environments using visual feedback. In this work we explore how the concept of pseudo-haptic feedback can be introduced in a collaborative scenario. A remote collaborative scenario in which two users interact with a deformable object is presented. Each user, through touch-based input, is able to interact with a deformable virtual object displayed in a standard display screen. The visual deformation of the virtual object is driven by a pseudo-haptic approach taking into account both the user input and the simulated physical properties. Particularly, we investigated stiffness perception. In order to validate our approach, we tested our system in a single and two-user configuration. The results showed that users were able to discriminate the stiffness of the virtual object in both conditions with a comparable performance. Thus, pseudo-haptic feedback seems a promising tool for providing multiple users with physical information related to other users’ interactions.

Ferran Argelaguet, Takuya Sato, Thierry Duval, Yoshifumi Kitamura, Anatole Lécuyer

### Centralizing Bias and the Vibrotactile Funneling Illusion on the Forehead

This paper provides a novel psychophysical investigation of head-mounted vibrotactile interfaces for sensory augmentation. A 1-by-7 headband vibrotactile display was used to provide stimuli on each participant’s forehead. Experiment I investigated the ability to identify the location of a vibrotactile stimulus presented to a single tactor in the display; results indicated that localization error is uniform but biased towards the forehead midline. In Experiment II, two tactors were activated simultaneously, and participants were asked to indicate whether they experienced one or two stimulus locations. Participants reported the funneling illusion—experiencing one stimulus when two tactors were activated—mainly for the shortest inter-tactor difference. We discuss the significance of these results for the design of head-mounted vibrotactile displays and in relation to research on localization and funneling on different body surfaces.

Hamideh Kerdegari, Yeongmi Kim, Tom Stafford, Tony J. Prescott

### Haptic Rendering for Under-Actuated 6/3-DOF Haptic Devices

Under-actuated 6/3-DOF haptic devices are mostly used for simple 3-DOF point-based haptic interaction because of missing torque feedback. In this work, we present a system involving sensory substitution and pseudo-haptic feedback that effectively simulate torque feedback using visuo-tactile cues. The proposed system was implemented into a 6-DOF haptic rendering algorithm and tested on an under-actuated haptic device in a user study. We found that by applying our torque simulation system, the torque perception increases significantly and that 6/3-DOF devices can be used in complex tasks involving 6-DOF interactions.

Petr Kadleček, Petr Kmoch, Jaroslav Křivánek

### A Change in the Fingertip Contact Area Induces an Illusory Displacement of the Finger

Imagine you are pushing your finger against a deformable, compliant object. The change in the area of contact can provide an estimate of the relative displacement of the finger, such that the larger is the area of contact, the larger is the displacement. Does the human haptic system use this as a cue for estimating the displacement of the finger with respect to the external object? Here we conducted a psychophysical experiment to test this hypothesis. Participants compared the passive displacement of the index finger between a reference and a comparison stimulus. The compliance of the contacted object changed between the two stimuli, thus producing a different area-displacement relationship. In accordance with the hypothesis, the modulation of the area-displacement relationship produced a bias in the perceived displacement of the finger.

Alessandro Moscatelli, Matteo Bianchi, Alessandro Serio, Omar Al Atassi, Simone Fani, Alexander Terekhov, Vincent Hayward, Marc Ernst, Antonio Bicchi

### Illusory Rotations in the Haptic Perception of Moving Spheres and Planes

Recently, we have shown that a translating bar on which blindfolded participants position their hand is perceived as also rotating. Here, we investigated whether such an illusory rotation would also be found if a sphere or a plane (i.e. a stimulus without a clear orientation) was used as translating stimulus. We indeed found similar rotation biases: on average a stimulus that translates over a distance of 60 cm has to rotate 25

$$^\circ$$

to be perceived as non-rotating. An additional research question was whether the biases were caused by the same underlying biasing egocentric reference frame. To our surprise, the correlations between the sizes of the biases of the individual participants in the various conditions were not high and mostly not even significant. This was possibly due to day-to-day variations, but clearly, more research is needed to answer this second research question.

Astrid M. L. Kappers, Wouter M. Bergmann Tiest

### Distinct Pseudo-Attraction Force Sensation by a Thumb-Sized Vibrator that Oscillates Asymmetrically

This paper describes the development of a thumb-sized force display for experiencing a kinesthetic illusory sensation of being continuously pushed or pulled. We previously succeeded in creating a sensation of being pulled with a prototype based on a crank-slider mechanism, but recently we did so with a thumb-sized actuator that oscillates asymmetrically. With this tiny and light force display, the directed force sensation is perceived just as strongly as with the previous larger prototypes. We conducted a user study using the method of paired comparisons. The results show that a specific vibrator with a 7-ms pulse at 40 Hz induces the sensation most clearly and effectively.

Tomohiro Amemiya, Hiroaki Gomi

### Obstacle Identification and Avoidance Using the ‘EyeCane’: a Tactile Sensory Substitution Device for Blind Individuals

One of the main challenges facing the blind and visually impaired is independent mobility without being obtrusive to their environment. We developed a tactile low-cost finger-size sensory substitution device, the EyeCane, to aid the Blind in obstacle identification and avoidance in an unobtrusive manner. A simplified version of the EyeCane was tested on 6 sighted blindfolded participants who were naïve to the device. After a short (2–3 min) training period they were asked to identify and avoid knee-to-waist-high (Side) and sidewalk-height (Floor) obstacles using the EyeCane. Avoidance included walking around or stepping over the obstacles. We show that in the fifth trial, participants correctly identified 87 ± 13.6 % (mean ± SD) and correctly avoided 63 ± 15 % of the side obstacles compared to 14 % in the control condition (p < 4E-10 and p < 1.1E-05 respectively). For Floor obstacles, participants correctly identified 79 ± 18.8 % and correctly avoided 41 ± %37.6 compared to the control’s 10 % (p < 0.002 and p < 0.06 respectively).

Galit Buchs, Shachar Maidenbaum, Amir Amedi

### Assessment of Tactile Languages as Navigation Aid in 3D Environments

In this paper we present the design and evaluate alternative tactile vocabularies to support navigation in 3D environments. We have focused on the tactile communication expressiveness by applying a prefixation approach in the construction of the tactile icons. We conducted user experiments to analyze the effects of both prefixation and the use of tactile sequences on the user’s performance in a navigation task. Results show that, even if tactile sequences are more difficult to process during the navigation task, the prefixed patterns were easier to learn in all assessed vocabularies.

Victor Adriel de J. Oliveira, Anderson Maciel

### Altering Distance Perception from Hitting with a Stick by Superimposing Vibration to Holding Hand

Distance perception by hitting objects with a handheld stick is an important cue for people with visual impairments who use a white cane in daily life. In a previous paper, we found that adding vibration to the thumb side of the cane shortened the perceived collision distance more than adding vibration to the little-finger side, which partly agrees with our hypothetical model. In this paper, we conducted a similar experiment, changing the real distance between the palm and the object to explore the robustness of our hypothetical model. The experimental results showed that perceived collision distance shortened regardless of the real distance, but may be easily induced when the object is placed far from the palm.

Ryuta Okazaki, Hiroyuki Kajimoto

### Passive Mechanical Skin Stretch for Multiple Degree-of-Freedom Proprioception in a Hand Prosthesis

In this paper, we present a passive linear skin stretch device that can provide proprioceptive feedback for multiple degrees of freedom (DOF) in a prosthetic hand. In a 1-DOF virtual targeting task, subjects performed as well with our device as with a vibrotactile array, and significantly better (

$$p<0.05$$

) than having no feedback at all. In a 3-DOF grip recognition task, subjects were able to classify six different grips with 88.0 % accuracy. Training took 6 min and the average time to classification was 5.2 s. Subjects were also able to match a set of target grip apertures with 11.1 % error on average.

Aadeel Akhtar, Mary Nguyen, Logan Wan, Brandon Boyce, Patrick Slade, Timothy Bretl

### A Visual-Haptic Multiplexing Scheme for Teleoperation Over Constant-Bitrate Communication Links

We propose a novel multiplexing scheme for teleoperation over constant bitrate (CBR) communication links. The proposed approach uniformly divides the channel into 1 ms resource buckets and controls the size of the transmitted video packets as a function of the irregular haptic transmission events generated by a perceptual haptic data reduction approach. The performance of the proposed multiplexing scheme is measured objectively in terms of delay-jitter and packet rates. The results show that acceptable multiplexing delays on both the visual and haptic streams are achieved. Our evaluation shows that the proposed approach can provide a guaranteed constant delay for the time-critical force signal, while introducing acceptable video delay.

Burak Cizmeci, Rahul Chaudhari, Xiao Xu, Nicolas Alt, Eckehard Steinbach

### Low-Cost 5-DOF Haptic Stylus Interaction Using Two Phantom Omni Devices

This paper introduces a haptic interface providing 5-DOF stylus interaction for applications requiring 3-DOF force and 2-DOF torque feedback. The interface employs two coupled Phantom Omni devices each offering 3-DOF force feedback and 6-DOF position sensing. The interface uses an inexpensive lightweight coupling and no additional actuators enabling the interface to maintain low inertia and stylus interaction, both similar to the original Phantom Omni device. The interface also maintains unconstrained rotation about the stylus’ longitudinal axis aiding in handheld manipulation. Kinematic analysis of the 5-DOF interface is presented and the usable workspace of the device is demonstrated.

Mats Isaksson, Ben Horan, Saeid Nahavandi

### The Effects of Force Feedback on Surgical Task Performance: A Meta-Analytical Integration

Since the introduction of surgical robots into clinical practice, there has been a lively debate about the potential benefits and the need to implement haptic feedback for the surgeon. In the current article, a quantitative review of empirical findings from 21 studies (

N

= 332 subjects) is provided. Using meta-analytical methods, we found moderate effects on task accuracy (

g

= .61), large effect sizes of additional force feedback on average forces (

g

= .82) and peak forces (

g

= 1.09) and no effect on task completion times (

g

= −.05) when performing surgical tasks. Moreover, the magnitude of the force feedback effect was attenuated when visual depth information was available.

Bernhard Weber, Sonja Schneider

### Switching Robust Control Synthesis for Teleoperation via Dwell Time Conditions

Control design for bilateral teleoperation is still an open problem, given that it is desirable to meet a proper balance in the inherent trade-off between transparency and stability. We propose the use of switching robust control, in which smooth switching among controllers is achieved by the existence of multiple Lyapunov functions with a special structure, linked by conditions of maximum average dwell time switching among controllers. We show the advantage of the proposed method by means of a control design synthesis for an 1-DoF teleoperation system, and by means of simulations of the corresponding closed loop system.

César A. López Martínez, René van de Molengraft, Maarten Steinbuch

### Performance Evaluation of a Surgical Telerobotic System Using Kinematic Indices of the Master Hand-Controller

This paper investigates how kinematics of the master hand-controller, in a teleoperated system, is related to performance of the entire system. Experimental validations are presented on a surgical robotic system by emulating a part of microsurgery procedure in a laboratory setting. Isotropy index is chosen as a quantitative kinematic tool. The performance of the system is evaluated using four measures: rates of slave and master actuators efforts as well as distances travelled by the slave end-effector and the haptic implement. Results indicate that when the haptic device moves within regions with higher isotropy index, the performance improves. In order to further enhance the performance, the master site is augmented by a clutch that is found helpful to increase the hand-controller dexterity.

Yaster Maddahi, Michael Greene, Liu Shi Gan, Tomas Hirmer, Rachael L’Orsa, Sanju Lama, Garnette Roy Sutherland, Kourosh Zareinia

### Development of Two-Handed Multi-finger Haptic Interface SPIDAR-10

This article describes the development of a wire-driven multi-finger haptic interface named SPIDAR-10(Space Interface Device for Artificial Reality), which can render a 3 degree-of-freedom spatial force feedback for human fingers through 4 wires attached to each fingertip. SPIDAR-10 enables users to manipulate virtual objects in a VR world with ten fingers of both hands. With two rotary cylindrical frames, which motors are mounted on, the interference of the wires can be reduced. A method of frame control is also proposed. The experimental results of the performance of the basic SPIDAR system and rotary frame are also given.

Lanhai Liu, Satoshi Miyake, Naoki Maruyama, Katsuhito Akahane, Makoto Sato

### A Human-Like Bilateral Tele-Handshake System: Preliminary Development

While developing a new human-like bilateral tele-handshake system that can provide multimodal sensations including visual, kinesthetic, tactile, temperature, and auditory, this paper proposes a 4-channel energy-bounding bilateral tele-handshake framework for stable and transparent kinesthetic sensations. Instead of directly measured fore, this framework uses position-based force feedback along with position signals. Preliminary experimental results with the LTE network showed somewhat natural kinesthetic feeling while remote handshaking.

Sungjun Park, Sangsoo Park, Sang-Yun Baek, Jeha Ryu

### Evaluation of Stretchable Conductor for Measuring Clothing Pressure

In this study, we developed a stretchable conductor and evaluated whether it is capable of measuring clothing pressure. The experimental relationship between electrical resistance and strain, and the results regarding the physical effects of the conductor on the textile showed that this device could be used to measure clothing pressure by being printed on the textile (with particular suitability when the textile is made from polyester). Furthermore, we clarify the current problems of the conductor such as the variation in the electrical resistance with time and the bending characteristics.

Katsunari Sato, Sayasa Otsubo, Teppei Araki, Tohru Sugahara, Katsuaki Suganuma

### The LegoPress: A Rehabilitation, Performance Assessment and Training Device Mechanical Design and Control

In this paper we present the LegoPress, a simple and cost-effective robotic device intended to be used for leg-press movements in rehabilitation and training. Basic adjustments can be done on the sitting position so as to maximize comfort and adapt the posture of the user depending on the desired training. The LegoPress has two motorized axes independently acting on the two legs. By means of force sensors positioned at the pedal level, a precise monitoring is possible. The force sensor is as well used to improve the impedance control, which enables to reproduce various behaviors. The device is not only able to mobilize the user’s legs but also to interact with her/him.

Jeremy Olivier, Maxime Jeanneret, Mohamed Bouri, Hannes Bleuler

### Receiver-Based Hybrid Sample Prediction for Error-Resilient Haptic Communication

We propose the use of a hybrid predictor at the receiver side of a teleoperation system to mitigate haptic artifacts due to packet losses. We define maximum wait times based on prediction angles for the sender to trigger new updates and for the receiver to switch prediction methods. Results show robust minimization of signal distortion in the presence of adverse transmission conditions while preserving the data rate conveniently low.

Fernanda Brandi, Eckehard Steinbach

### Multi-digit Softness: Development of a Tactile Display to Render Softness Feeling on Multiple Fingers

This paper describes a new tactile display that can present softness sensations to multiple phalanges on multiple fingers. Contact width control through sheet wrapping is adopted as a softness rendering method for each finger. Three separate mechanisms for contact width control for three fingers are integrated in one device. Passive mechanical linkages are employed to provide sensations to the whole fingers. The paper reports on the design of the developed device, as well as the result of psychophysical experiment that investigated the contributions of each phalange and finger in softness perception on this display.

Toshiki Kitazawa, Fuminobu Kimura, Akio Yamamoto

### Haptic Rendering on Deformable Anatomical Tissues with Strong Heterogeneities

This paper is focus on the development of a haptic rendering method to simulate interactions with heterogeneous deformable materials, such as anatomical components. Indeed, the strong heterogeneities of the biological tissues involves numerical and real-time issues to simulate the deformations and the mechanical interactions between the organs and the surgical tools. In this paper, we propose a new haptic algorithm adapted to the modeling of heterogeneous biological tissues, based on non-linear finite element model. The central contribution is the use of a triple asynchronous approach: one loop at low rate, which computes a preconditionner that solves the numerical conditioning problems; a second at intermediate rate, to update the model of the biological simulation; and the haptic loop which provides the feedback to the user at high rate. Despite of the desynchronization, we show that the calculation of haptic forces remains accurate compared to the model. We apply our method to a challenging microsurgical intervention of the human middle ear. This surgery requires a delicate gesture in order to master the applied forces.

Guillaume Kazmitcheff, Hadrien Courtecuisse, Yann Nguyen, Mathieu Miroir, Alexis Bozorg Grayeli, Stéphane Cotin, Olivier Sterkers, Christian Duriez

### Grasping Control in Three-Fingered Robot Hand Teleoperation Using Desktop Haptic Device

This paper presents a three-fingered robot hand teleoperation system using desktop haptic device as the master manipulator. The grasp mapping and force feedback methods are developed for the system. Grasp forces of the robot hand are transformed to proper feedback force in master side. Operator controls the robot hand to grasp and hold different objects depending on the force feedback rather than visual feedback. We demonstrated that a wide range of objects, whose properties are well known by operator, were safely and stably grasped and the force based grasping control was more reliable than visual feedback based control. The intuitive and easy-to-realize system raises a new control scheme in robot hand teleoperation.

Lingzhi Liu, Guanyang Liu, Yuru Zhang

### A High-Fidelity Surface-Haptic Device for Texture Rendering on Bare Finger

We present the design and evaluation of a high fidelity surface-haptic device. The user slides a finger along a glass plate while friction is controlled via the amplitude modulation of ultrasonic vibrations of the plate. A non-contact finger position sensor and low latency rendering scheme allow for the reproduction of fine textures directly on the bare finger. The device can reproduce features as small as 25

$$\upmu$$

m while maintaining an update rate of 5 kHz. Signal attenuation, inherent to resonant devices, is compensated with a feedforward filter, enabling an artifact-free rendering of virtual textures on a glass plate.

Michaël Wiertlewski, Daniele Leonardis, David J. Meyer, Michael A. Peshkin, J. Edward Colgate

### Task-Oriented Approach to Simulate a Grasping Action Through Underactuated Haptic Devices

Force rendering is important in underactuated haptic systems. Underactuation means that some force directions at the contacts cannot be rendered because of the lack of actuation. In this paper we propose to exploit the knowledge of the task to mitigate the effect of the underactuation. The simulation of a grasp is considered and two alternative algorithms are proposed to improve the sensitivity in the underactuated system. The basic idea is to exploit the actuated force direction, optimizing the force feedback according to the type of forces involved in the specific grasping task. These forces can be squeezing forces or forces able to move the grasped object. Experiments show that the proposed task–oriented force rendering considerably increases the ability of perceiving the properties of the grasped virtual object.

Leonardo Meli, Domenico Prattichizzo

### Integration of a Particle Jamming Tactile Display with a Cable-Driven Parallel Robot

Integration of a tactile display onto the end effector of a robot allows free-hand exploration of an encountered-type environment that provides both kinesthetic and cutaneous feedback. A novel tactile display approach, called Haptic Jamming, uses a combination of particle jamming and pneumatics to control the stiffness and shape of a surface. The tactile display mounts to the cable-driven platform of a kinesthetic system for medical simulation, called KineSys MedSim. The parallel structure of the robot provides a high strength-to-weight ratio for kinesthetic feedback in combination with a spatially aligned visual display. Its controller uses hand tracking to move the platform to the portion of the workspace the user is reaching toward. Data from a lump localization simulation demonstrates that the integrated system successfully tracks the user’s hand and reconfigures the tactile display according to the location of the end effector.

Andrew A. Stanley, David Mayhew, Rikki Irwin, Allison M. Okamura

### Humanoid Robot Teleoperation with Vibrotactile Based Balancing Feedback

One of the main challenges while teleoperating a humanoid robot consists in maintaining the slave’s balance while satisfying the operator’s intention. The main goal of this work is to settle whether feeding back the robot’s balance state to the operator by the mean of a vibrotactile belt can lead to an enhanced quality teleoperation. This study examines if an adequate cutaneous guidance can enable the operator to understand when the robot is approaching a loss-of-balance configuration, and use this information to adjust his teleoperation strategy. To achieve this objective, three different feedback patterns were compared during an initial experimental study. The evaluation focused on the subjects capacity to recognize the boundaries of a virtual workspace under each feedback mode and to adapt accordingly their teleoperated motions. The best suited feedback mode was selected and used during a second experiment which compared the performances obtained with and without tactile feedback during the teleoperation of the humanoid robot COMAN. Results clearly reveal that the cutaneous feedback of the slave’s balance state leads towards an enhanced quality teleoperation combining an increased safety as well as an unrestrained use of the entire stable workspace.

Anais Brygo, Ioannis Sarakoglou, Nadia Garcia-Hernandez, Nikolaos Tsagarakis

### Comparison of Multimodal Notifications During Telesurgery

This paper examines the utility of multimodal feedback during telesurgery to notify surgeons of excessive force application. Average puncture forces were characterized for varied thicknesses of an artificial membrane, and human operators then attempted to apply a maximum force to the membranes without causing a puncture via an experimental telesurgical apparatus. Operators were notified via different sensory modalities when the force exerted by the tool-tip exceeded a pre-established force margin, defined as a set percentage of the average puncture force. Various combinations of auditory and vibrotactile notifications both with and without force feedback were compared in order to investigate the relationship between feedback modality, force margin, and puncture force. Factor screening results identify multiple two-factor interactions as having statistically significant effects on both the maximum applied force and task completion time, warranting further investigation. Notifications of any type decreased both response variables for operators who relied on them.

Rachael L’Orsa, Kourosh Zareinia, Chris Macnab, Garnette Roy Sutherland

### A Multi-DOF Haptic Representation Using Suction Pressure Stimuli on Finger Pads

Humans can perceive external forces applied on a grasping tool based on skin pressure distribution at multiple contact areas during grasp. The authors have tried to represent external forces and torques by controlling the skin pressure distributions using suction stimuli and confirmed the potential but in a heuristic manner. In this paper, we investigate an improved method of skin stimulation based on a combination of psychophysical experiments and mechanical simulation. We focus on a simplification method of the complex strain energy density (SED) distribution at the contact areas with four quadrant values (SED index). The relationship between suction pressure and SED index was achieved by connecting the experiment and the mechanical simulation. We confirmed that a suitable SED index could represent the magnitudes of forces in multiple directions with a linear function. Experimental results also showed that the proposed method could represent arbitrary directions between pairs of the orthogonal axes.

Daiki Maemori, Lope Ben Porquis, Masashi Konyo, Satoshi Tadokoro

### Evaluating the BioTac’s Ability to Detect and Characterize Lumps in Simulated Tissue

Surgeons can detect and characterize tumors in open surgery by palpating tissue with their fingertips, but palpation is not currently possible in minimally invasive surgery (MIS). Motivated by the goal of creating an automatic palpation tool for MIS, we evaluated the SynTouch BioTac sensor’s ability to detect and characterize lumps in simulated tissue. Models were constructed from silicone rubber with rigid spheres of three sizes embedded at three depths, plus models without embedded lumps. Electrode impedance and DC pressure were recorded as each model was indented into the BioTac at sixteen indentation depths up to 4.0 mm. Support vector machine classifiers were trained on subsets of the data and tested on trials from withheld models for three tasks: lump detection, lump size characterization, and lump depth characterization. The lump detection and lump size classifiers achieved relatively high accuracies, especially at the deepest indentation depths, but the lump depth classifier performed no better than chance.

Jennifer C. T. Hui, Katherine J. Kuchenbecker

### A Genetic Algorithm Approach to Identify Virtual Object Properties for Sharing the Feel from Virtual Environments

Haptics has provided people with new computer interaction styles across a range of applications. However, it is difficult to share haptic experiences from haptic virtual environments (HVEs). In this paper, we introduce a genetic algorithm (GA) approach, which is used to identify the virtual object’s properties (e.g. stiffness, friction coefficient and geometry parameters) based on haptic recordings, so that the haptic rendering can be reproduced without requiring the original HVE software to be deployed.

Yongyao Yan, Greg S. Ruthenbeck, Karen J. Reynolds

### Estimation of Finger Pad Deformation Based on Skin Deformation Transferred to the Radial Side

Techniques to measure the deformation of finger pad when rubbing material surfaces are important for the analysis of textural sensations and development of tactile texture displays. However, such measurements are difficult because when the finger pad is in contact with the material surfaces, it is not exposed for measurement. We developed a technique to estimate finger pad shear deformation by using the skin deformation transferred to the side of the fingertip. Good agreement was shown between measured finger pad accelerations and those estimated by our method. The skin deformation of the finger side can be effectively used to estimate that of the finger pad with an average accuracy of 0.93.

Yoichiro Matsuura, Shogo Okamoto, Yoji Yamada

### Haptic Rendering of Tissue Stiffness by the Haptic Enhanced Reality Method

We have developed a prototype medical simulator that uses the haptic enhanced reality (HER) method. In this method, the force from a haptic device overlaps the reaction force from a base object. The key idea is to use a base object that has a material property similar to that of the target and to combine the virtual force produced by the haptic device with the reaction force from the base object. To confirm the feasibility of the proposed method, we conducted an experiment in which the stiffness at different points on a target liver was rendered based on the observed luminance at each point.

Yoshihide Otsuru, Toshio Tsuji, Yuichi Kurita

### Simulation of Soft Finger Contact Model with Rolling Effects in Point-Contact Haptic Interfaces

Computation of contact point trajectories and forces exchanged between two bodies in contact are relevant to several disciplines. The solutions proposed in the literature are often too complex to be implemented in real time simulations, especially if rolling effects are considered. In this chapter, an algorithm for fast simulation of soft-finger contact model with rolling effects is proposed. The main idea is to use Euler angle decomposition algorithm to quantitatively describe the torque exchanged about the normal at the contact point and the motion of the contact point due to rolling. The proposed algorithm is validated with simulations and a preliminary application to point-contact haptic interface is proposed.

Gionata Salvietti, Monica Malvezzi, Domenico Prattichizzo

### Haptics Processing Unit Software Architecture for Transportable High Dynamics Force-Feedback Coupling

This article is a contribution to today’s stream of research studying the interests of employing a Haptics Coprocessing Unit (HPU) for force-feedback interaction, and possible core features and hardware/software architectures of such HPU. It introduces a force-feedback software framework, called CORDIS-In, powered by a DSP-based HPU. CORDIS-In’s design was driven so as to obtain a transportable platform, however able to provide very high dynamics force-feedback coupling. It provides time deterministic synchronous computing of any mass-interaction physics-based network, possibly at high simulation rates, high precision and programmability in adjusting the mechanical coupling of the user and the simulation through the device, and generic communication protocols with the host.

Annie Luciani, Nicolas Castagne, James Leonard

### Geometrically Limited Constraints for Physics-Based Haptic Rendering

In this paper a single-point haptic rendering technique is proposed which uses a constraint-based physics simulation approach. Geometries are sampled using point shell points, each associated with a small disk, that jointly result in a closed surface for the whole shell. The geometric information is incorporated into the constraint-based simulation using newly introduced geometrically limited contact constraints which are active in a restricted region corresponding to the disks in contact. The usage of disk constraints not only creates closed surfaces, which is important for single-point rendering, but also tackles the problem of over-constraint contact situations in convex geometric setups. Furthermore, an iterative solving scheme for dynamic problems under consideration of the proposed constraint type is proposed. Finally, an evaluation of the simulation approach shows the advantages compared to standard contact constraints regarding the quality of the rendered forces.

Thomas Knott, Torsten Kuhlen

### Vibration and Subsequent Collision Simulation of Finger and Object for Haptic Rendering

Humans can discriminate object’s materials [

5

,

7

,

9

] and tapping position [

8

] perceiving tapping vibrations. Susa

et al.

[

4

] proposed to simulate natural vibration of object to present arbitrary structured objects. However, the vibration of the tapping finger and subsequent collisions between the finger and the object are not simulated.

This paper proposes a simulation model for tapping, which considers finger’s vibration motion and subsequent collisions between the object and the finger. Experimental results show that the proposed method renders realistic event based forces including impact impulse, decayed waves and subsequent collisions.

Shoichi Hasegawa, Yukinobu Takehana, Alfonso Balandra, Hironori Mitake, Katsuhito Akahane, Makoto Sato

### Computational Modeling Reinforces that Proprioceptive Cues May Augment Compliance Discrimination When Elasticity Is Decoupled from Radius of Curvature

Our capability to discriminate object compliance is based on cues both tactile and proprioceptive, in addition to visual. To understand how the mechanics of the fingertip skin and bone might encode such information, we used finite element models to simulate the task of differentiating spherical indenters of radii (4, 6 and 8 mm) and elasticity (initial shear modulus of 10, 50 and 90 kPa). In particular, we considered two response variables, the strain energy density (SED) at the epidermal-dermal interface where Merkel cell end-organs of slowly adapting type I afferents reside, and the displacement of the fingertip bone necessary to achieve certain surface contact force. The former variable ties to tactile cues while the latter ties to proprioceptive cues. The results indicate that distributions of SED are clearly distinct for most combinations of object radii and elasticity. However, for certain combinations – e.g., between 4 mm spheres of 10 kPa and 8 mm of 90 kPa – spatial distributions of SED are nearly identical. In such cases where tactile-only cues are non-differentiable, we may rely on proprioceptive cues to discriminate compliance.

Yuxiang Wang, Gregory J. Gerling

### Electrovibration Modeling Analysis

Electrostatic attraction may be used to modulate the apparent friction coefficient between two surfaces. Applied to the human finger and a polarized interface, the principle can modify the user perception of the interface surface. In this paper, the different steps towards the modeling of the electrovibration phenomenon are developed. An investigation on the current modeling will be carried out, with a focus on the temporal evolution and frequency dependence of the stimulus. Thus, an improvement of the modeling will be proposed to take into account this major effect, and then, it will be checked with an experimental set-up and compared with literature results.

Eric Vezzoli, Michel Amberg, Frédéric Giraud, Betty Lemaire-Semail

### Functional Microanatomical Model of Meissner Corpuscle

From Finite Element Model to Mechano-Transduction

A multi-scale framework of human tactile sensation has been developed. The framework consists of two mechanical stages and a post-processing stage. In the first stage, a fingerpad and a stimulus are modelled. The second stage contains a slab of skin containing a Meissner corpuscle. The mechanical output of the second stage is processed by a mechanosensory channel activation model and a spike generator. To our knowledge, this is the first framework linking different levels of sensory processing from mechano-transduction to spike-train comparison. The results of the model are compared to the microneurographical data of a RA1 mechanosensory afferent fibre. The framework could be used as a tool for studying the finger pad-surface interaction in scientific and industrial communities related to touch.

Teja Vodlak, Zlatko Vidrih, Primoz Pirih, Ales Skorjanc, Janez Presern, Tomaz Rodic

### Modeling Pneumatic Actuators for a Refreshable Tactile Display

In this paper, we develop a dynamic lumped parameter model of a pneumatic membrane actuator to inform the design of a shape display that meets force, speed and spatial density specifications for refreshable braille. A system identification experiment is undertaken to determine relevant system parameters that remain fixed under variation of the lengths of the connecting tubes and cavity volumes. Parameter values were found to fit a numerical solution to a step response in pressure for multiple line lengths. Two additional experiments were conducted using various applied pressures and actuator cavity volumes to validate the model. Extrapolation of the model to the dimensions of a first prototype scaled at 5/3 braille dot size and spacing predicts a 1.4 Hz bandwidth whereas experiments yield a 1.7 Hz bandwidth.

Alexander Russomanno, R. Brent Gillespie, Sile O’Modhrain, James Barber

### Modeling the Weber Fraction of Vibrotactile Amplitudes Using Gain Control Through Global Feedforward Inhibition

Weber’s law describes the linear drop of discriminative performance with increased base intensity of a stimulus. So far, this phenomenon has been modeled using multistable attractor decision networks based on the principle of biased competition between two mutually inhibiting recurrent neural populations. Due to the sensitive balance in a multistable fluctuation-driven regime, these decision models can only account for Weber’s law in a narrow stimulus range. Psychophysical data shows though that the human exhibits this characteristic for a broad stimulus range. Recent neurophysiological evidence suggests that global feedforward inhibition expands the dynamic range of cortical neuron populations and acts as a gain control. In this paper, we introduce a computational model that exploits this type of inhibition and shows through a fit between simulation results and psychophysical data that it is a potential explanation for the principle mechanism behind Weber’s law.

Ken E. Friedl, Yao Qin, Daniel Ostler, Angelika Peer

### Device for Estimation of Weight and Material of Contents by Shaking

Haptic stimuli rely mainly on interactive motion. When a person shakes a box, he or she can guess at the physical properties of its contents. This is often based on haptic stimuli. This paper describes the development of a haptic device and control system, as well as the modeling and simulation of a virtual box and its contents. It also discusses an investigation into differences in the manner of shaking depending on the properties of the model and the feedback conditions.

Takeshi Yamamoto, Koichi Hirota

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