List of Technical Papers

The technical papers to be presented at World Haptics 2015 are listed below in no particular order. Click on the titles to see abstracts.

Single Track Featured Papers

Patrice Lambert, Just Herder
This paper introduces a novel parallel architecture that provides 6 DOF motion and 1 DOF grasping capabilities while all the motors are located at the base. Classical parallel haptic devices usually do not provide grasping capabilities since all motors are located on the base. Thanks to a novel configurable platform, the grasping capability of this haptic device is part of the mechanical architecture itself and can be fully controlled by base-located motors.
Ildar Farkhatdinov, Arnaud Garnier, Etienne Burdet
We present an MR compatible haptic interface for human motor control studies, which can be easily installed and removed from the scanner room. The interface is actuated by a shielded motor located 2.1 m away from the MR scanner. Torque is transmitted to a subject's wrist through cable transmission. The handle is adjustable to different hands size, enabling comfortable wrist movements. A dynamic model of the interface is presented and identified for position and torque control modes. Phantom MR compatibility test in clinical environment showed that the interface is compatible with strong magnetic field and radio frequency emission.
Valerie Morash
Movement strategies were investigated in a one-handed haptic search task where blindfolded sighted participants used either one or five fingers to find a landmark on an unstructured tactile map. Search theory predicts that systematic strategies, such as parallel sweeps and spirals, should be more prevalent when the searcher's detection radius is small (one finger) than when the detection radius is large (five fingers). Movement patterns were classified as either non-systematic or systematic, and systematic strategies were more common in one-finger than five-finger searches. Therefore, systematic haptic search strategies are used and modulated by detection radius for untrained sighted participants.
Jess Hartcher-O'Brien, Malika Auvray, Vincent Hayward
Vision-to-touch prostheses typical code space-to-space, space-to-intensity, or space-to-frequency. Yet, organisms use a space-to-time-delay mapping to anticipate and avoid impending collisions. Many organisms have developed computational short-cuts where distance-to-target is proportional to a time-span. Can untrained humans spontaneously employ such a short-cut to estimate distance-to-obstacle in the absence of vision? Tactile feedback, a pulse, was delivered to the hand with a delay proportional to an obstacle's distance detected by the device's optical-rangefinder. Observers were naïve to the nature of the code but quickly calibrated and accurately estimated distance within a range of 4m for delays corresponding to a velocity of 1m/s.
Jongman Seo, Seungmoon Choi
Vibrotactile flows refer to vibrotactile sensations that move continuously on the surface of a mobile device. This paper extends the dimension of vibrotactile flows to two dimensions by means of edge flows -- vibrotactile flows that rotate along the edges of a rectangular device. We carried out a longitudinal user study to measure the information transmission capacity of 32 edge flows. Results showed that the information transmission capacity of the edge flows was 3.70 bits, which is greater than for most previous studies, and that some extent of practice is required for robust identification although it can take place quickly.
Rebecca Fenton Friesen, Michael Wiertlewski, Michael Peshkin, Ed Colgate
This paper presents the design of a bioinspired artificial fingertip that resembles the mechanical behavior of a human fingertip under conditions of both static deformation and high frequency excitation. Force-deformation characteristics and response to a transient mechanical perturbation are both shown to be in good qualitative agreement with those of a real finger. More importantly, the fingertip exhibits friction reduction when interacting with TPads (variable friction tactile displays based on transverse ultrasonic vibrations). Comparison with artificial fingertips that do not exhibit friction reduction suggests that mechanical damping characteristics play a key role in the amount of friction reduction achieved.
Emma Treadway, Brent Gillespie, Darren Bolger, Amy Blank, Marcia O'Malley, Alicia Davis
The use of haptic display to refer cues from a prosthetic terminal device promises to improve the function of myoelectrically controlled upper limb prostheses. This promise is often evaluated in experiments involving non-amputees. However, the availability of auxiliary haptic feedback from an intact hand may confound attempts to use non-amputees as stand-ins for amputees. In this paper we test the influence of auxiliary haptic feedback on myoelectric control by asking non-amputees to use myoelectric control to perform visual and haptic compensatory tracking with either a hard object, soft object, or no object in their grasp.
Matti Strese, Clemens Schuwerk, Eckehard Steinbach
When a tool is dragged over a surface, vibrations are induced that can be captured using acceleration sensors. This paper presents an approach for tool-mediated surface classification which is robust against varying scan-time parameters and works without explicit scan force and velocity measurements. We focus on mitigating the effect of varying contact force and hand speed conditions on our proposed features as a prerequisite for a robust machine-learning-based approach for surface classification. Our approach allows for classification of surfaces under freehand movement conditions. We achieve a classification accuracy of 95% with a Naïve-Bayes Classifier for a database of 69 textures.
Colin Ho, Jonathan Kim, Sachin Patil, Ken Goldberg
We introduce a novel haptic display designed to reproduce the sensation of both lateral and rotational slip on a user's fingertip. The device simulates three-degrees-of-freedom of slip by actuating four interleaved tactile belts on which the user's finger rests. We present the specifications for the device, the mechanical design considerations, and initial evaluation experiments. We conducted experiments on user discrimination of tangential lateral and rotational slip. Initial results from our preliminary experiments suggest the device design has potential to simulate both tangential lateral and rotational slip. Source files: https://github.com/Slip-Pad
Hiroaki Yano, Shoichiro Taniguchi, Hiroo Iwata
In order to realize the fingertip of a user is freed from the restrictions of the end effector of haptic interface, separate contact and reaction force points are selected for haptic rendering. A prototype system, which consists of a motion tracker, a 2-DOF haptic interface with a force sensor, and a visual display, is developed. The system measures the position of the fingertip of the user and produces an appropriate horizontal force on the thenar eminence of the user. By using the interface, the user can perceive the surfaces of 3D virtual objects and the frictional force on the surface.
Yongseok Lee, Inyoung Jang, Dongjun Lee
For Wearable finger-based haptics with cutaneous \ feedback, one of the key challenges is the finger-tracking, which can never be perfect, yet, if used in VR, would \ be adequate as long as its tracking error is under a certain \ detection threshold. For such system, we aim to quantitatively answer the \ following questions: 1) what is the detection threshold (JND) of visual-proprioceptive conflict \ (i.e., error tolerance of the finger-tracking system in VR); and 2) \ is it possible to further reduce this visual-proprioceptive conflict \ by utilizing cutaneous haptic feedback. These results \ would be useful to determine the design specification of finger tracking \ systems.

Dual Track Papers

Alejandro Melendez-Calderon, Moria Fisher, Michael Tan, Etienne Burdet, James Patton
Interactive technologies can help people acquire movement skills, and one way is by using visual distortions to boost neural adaptation. An extreme version of such approach is to train a movement without moving by creating a synesthetic illusion of movement -- displaying virtual motions when there is none. While this approach uses no proprioceptive error to drive adaptation, our results show encouraging evidence that motor skills can be acquired through such illusions of movement.
Siyan Zhao, Ali Israr, Roberta Klatzky
Handheld and wearable devices engage users with simple haptic feedback, e.g., alerting and pulsating. Here we explored intermanual apparent tactile motion -- illusory movement between two hands as a means to enrich such feedback. A series of psychophysical experiments determined the control space for generating smooth and consistent motion across the hands while users held the device and a multimodal factor to match moving visual cues across the screen to moving tactile motion across hands. The results of this research are useful for media designers and developers to generate reliable motion across the hands and integrate haptic motion with visual media.
Tomi Nukarinen, Jussi Rantala, Ahmed Farooq, Roope Raisamo
Navigation systems usually require visual or auditory attention. Providing the user with haptic cues could potentially decrease cognitive demand in navigation. This study is investigating the use of haptic eyeglasses in navigation. We conducted an experiment comparing directional haptic cues to visual cueing in a car navigation task. The results showed that in comparison to the visual text cues the haptic cues were reacted to significantly faster. Haptic cueing was also evaluated as less frustrating than visual cueing. The paper suggests that haptic eyeglasses can decrease cognitive demand in navigation and have many possible applications.
Arash Mohtat, Jozsef Kovecses
Producing a sharp feeling of impact is important for high-fidelity force feedback rendering of virtual objects. This paper studies the direct impulse-based rendering paradigm to achieve this goal. Three challenges are investigated: (a) counteracting the undesired sampled-data-induced energy dissipation; (b) meeting actuation limits by impulse distribution; and, (c) rendering resting contacts by hybridizing impulse and penalty-based formulations. Then, a unified control-oriented framework entitled the generalized contact controller is developed for implementing the proposed formulations and solutions. Our simulation and experimental results show the promise of the framework for generating a sharper unfiltered feeling of impact at relatively low sampling rates.
Alexandra Lezkan, Knut Drewing
In softness exploration participants repeatedly indent the surface. We investigated how executed peak forces are modulated for different indentations depending on the softness of the object. We assumed that movement control is determined by available predictive and sensory signals. The results show that participants systematically apply lower forces when sensory or predictive signals indicate softer objects as compared to harder objects. Thus, we consider softness exploration as a sensorimotor control loop, in which predictive and sensory signals determine movement control. Further, predictive signals are shown to maintain highly important throughout the entire exploration, even in the presence of sensory signals.
Xiao Xu, Burak Cizmeci, Clemens Schuwerk, Eckehard Steinbach
We propose a perceptual haptic data reduction approach for teleoperation systems which use the time domain passivity approach (TDPA) as their control architecture for dealing with time-varying communication delay. Our goal is to reduce the packet rate over the communication network while preserving system stability in the presence of time-varying and unknown delays. Experiments show that our proposed approach can reduce the average packet rate by up to 80%, without introducing significant distortion. In addition, the proposed approach outperforms the existing wave variable-based approaches in both packet rate reduction and subjective preference for the tested communication delays.
David Meyer, Michael Peshkin, Edward Colgate
Texture modeling strives to encapsulate the important properties of texture in a concise representation for interpretation, storage, and rendering. Models for tactile texture have yet to describe a representation that is both perceptually complete and sufficiently compact. In this work, we take inspiration from models of visual and auditory texture and propose a representation of tactile texture that separates localized features from textural aspects. We investigate the length scales at which humans can localize features, and represent textures as spectrograms that capture those features. Additionally, we demonstrate a reconstruction algorithm capable of recreating texture from a spectrogram without perceptual consequence.
Irfan Hussain, Leonardo Meli, Claudio Pacchierotti, Gionata Salvietti, Domenico Prattichizzo
In this paper, we present a robotic extra finger coupled with a vibrotactile ring interface. The human user is able to control the motion of the robotic finger through a switch placed on the ring, while being provided with vibrotactile feedback about the forces exerted by the robotic finger. To understand how to control the vibrotactile interface to evoke the most effective cutaneous sensations, we executed perceptual experiments to evaluate its absolute and differential thresholds. We also carried out a pick-and-place experiment with ten subjects. Haptic feedback significantly improved the task's performance.
Anton Filatov, Ozkan Celik
In this paper, we present results from two human subject experiments focusing on effect of prehensor stiffness on object stiffness discrimination task performance in a body-powered prosthesis. We broaden the existing knowledge base by (1) using an experimental setup which mimics the control inputs of a body-powered prosthesis operated in voluntary closing mode, and (2) exploring the impact of end effector stiffness modulation on the quality of haptic feedback the user receives about the environment. Results indicated that tuning of prehensor stiffness can increase the performance of the user in correctly and more easily identifying objects with varying stiffness.
Brian Tse, Alaistair Barrow, Barry Quinn, William Harwin
Using haptic interfaces to assist the training of undergraduate dentists provides a unique opportunity to advance rendering algorithms and engineering of haptic devices. In this paper we use the dental context to explore a rendering technique called smoothed particle hydrodynamics (SPH) as a potential method to train students on appropriate techniques for insertion of filling material into a previously prepared (virtual) dental cavity. The paper also considers how problems of haptic rendering might be implemented on a Graphical Processing Unit (GPU) that operates in the haptics control loop. Novel smoothing function in SPH was developed and its flexibility is presented. \
Sofiane Ghenna, Frederic Giraud, Christophe Giraud-Audine, Michel Amberg, Betty Lemaire-Semail
The goal of our study is to provide a multi-touch ultrasonic tactile stimulation on a surface using ultrasonic vibrations. We propose a method to control ultrasonic waves on a beam, allowing to obtain a Multi-touch ultrasonic tactile stimulation in two points, to give the sensation to two fingers, from two piezoelectric transducers. The multi-modal approach and the vector control method are used to regulate the vibration amplitude, in order to modulate the friction coefficient with the fingers. A psychophysical experiment with 6 subjects is conducted to demonstrate the idea.
Eric Vezzoli, Brygida Dzidek, Thomas Sednaoui, Frederic Giraud, Michael Adams, Betty Lemaire-Semail
Ultrasonic vibration of a plate can be used to modulate the friction of a finger pad sliding on a surface. This modulation can modify the user perception of the touched object and induce the perception of textured materials. In the current paper, an elastic model of finger print ridges is developed. A friction reduction phenomenon based on non- Coulombic friction is evaluated based on this model. Then, a comparison with experimental data is carried out to assess the validity of the proposed model and analysis.
Wouter Bergmann Tiest, Vincent Hayward
We have investigated differences in perceived object size when exploring the inside or outside of objects. Ten blindfolded subjects compared the size of circular disks and holes using either the index finger, two different probes, the finger-span method, or an infinitesimal virtual probe. For the large probe and the finger-span method, an object felt on the inside was perceived as smaller than an object felt on the outside. This indicates that subjects are unable to sufficiently correct for the diameter of the probe when exploring objects. Without a probe, most subjects perceived the objects to be bigger on the inside.
Tommaso Lisini Baldi, Mostafa Mohammadi, Stefano Scheggi, Domenico Prattichizzo
In the last years, wearable haptic technologies became very promising since they provide the users with tactile force feedback via small and wearable interfaces. However, they have no position sensing thus additional technologies are required. In this paper we present a sensing glove based on inertial and magnetic sensors for hand tracking which can be combined with cutaneous devices for the rendering of the force feedback. Preliminary experiments showed the effectiveness of the proposed approach. A comparison between using the glove with and without the cutaneous devices was presented.
Eder Miguel, Maria Laura D'Angelo, Ferdinando Cannella, Matteo Bianchi, Mariacarla Memeo, Antonio Bicchi, Darwin G. Caldwell, Miguel A. Otaduy
The computation of skin forces and deformations for tactile rendering requires an accurate model of the extremely nonlinear behavior of the skin. In this work, we first describe a measurement setup that enables the acquisition of contact force and contact area in the context of controlled finger indentation experiments. Second, we describe an optimization procedure that estimates the parameters of strain-limiting deformation models that match best the acquired data. Together, we achieve the characterization of finger mechanics and the design of an accurate nonlinear skin model for tactile rendering.
Hojin Lee, Ji-Sun Kim, Seungmoon Choi, Jae-Hoon Jun, Jong-Rak Park, A-Hee Kim, Han-Byeol Oh, Hyung-Sik Kim, Soon-Cheol Chung
This paper reports that lasers radiated to a thin light-absorbing elastic medium attached on the skin can elicit tactile sensations of mechanical tap with little individual variability. The underlying mechanism is thought to be the thermoelastic effect of laser, which creates elastic waves in the medium. We characterize the associated stimulus by measuring its physical properties. Its perceptual identity is also confirmed by comparing the laser stimulus to mechanical and electrical stimuli using perceptual spaces. To our knowledge, this is the first study that discovers the possibility of indirect laser radiation for mid-air tactile rendering. \ \
Gaofeng Yang, Dangxiao Wang, Yuru Zhang
In this paper, we studied how the accuracy of the force control could be enhanced through repetitive training. Participants were trained to apply a target force under concurrent visual feedback (Group A) and delayed visual feedback (Group B). After each training session, participants took a force test without feedback. The results show that Group B achieved the expected accuracy faster than Group A and suggest the delayed feedback appears to be more effective on consolidating motor memory in force control. Our finding opens a new opportunity to further explore the relationship between feedback and cognitive process of motor skill learning.
Dong-Bach Vo, Stephen Brewster
While mid-air gestures offer new possibilities to interact with or around devices, some situations, such as interacting with applications, playing games or navigating, may require visual attention to be focused on a main task. Ultrasonic haptic feedback can provide 3D spatial haptic cues that do not demand visual attention for these contexts. In this paper, we present an initial study of active exploration of ultrasonic haptic virtual cues that investigates the spatial localization with and without the use of the visual modality. Our findings will allow designers to create better mid-air interactions using this new form of haptic feedback. \
Takeshi Yamamoto, Koichi Hirota
The authors have investigated virtual realization of the shaking interaction using a haptic device that can present inertial force. This paper reports experiments on the discrimination and estimation of content's weight through the shaking interaction. In the experiments, the recognition of weight of solid and liquid contents by the subject was evaluated using the real box and the haptic device. The result proved that the device can present solid content in a similar accuracy to the real box. Moreover, it was suggested that the motion of the gravity center has a significant effect on the recognition of the content weight.
Anshul Singhal, Lynette Jones
Thermal stimuli provide a novel dimension to present information to users of hand-held devices provided the inputs are tailored to the properties of the sensory system. In this experiment thermal pattern identification was measured on the hand using six stimuli that varied with respect to the direction, magnitude and rate of temperature change. The individual mean scores ranged from 80% to 98% correct with an overall mean of 91%. The Information Transfer values ranged from 1.76 to 2.49 bits with a group mean of 2.26 bits. These findings indicate that thermal icons offer considerable potential for presenting information.
Carsten Neupert, Sebastian Matich, Christian Hatzfeld, Mario Kupnik, Roland Werthschützky
Pseudo haptic sensation is an illusion based on visual stimuli. In virtual environments it is used to simulate material properties such as stiffness, mass and friction. Transferring the principle of pseudo-haptic feedback to real haptic teleoperation systems can provide a haptic sensation of an interaction without active haptic feedback. \ \ In this work, we discuss the usability of pseudo haptic feedback for its application in teleoperation systems. Therefore, the mechanisms of pseudo-haptic feedback are explained theoretically and are implemented to a one degree of freedom teleoperation system. \ \ Experiments with ten subjects show, that pseudo-haptic feedback is principally usable for haptic teleoperation. \
Zhaoyuan Ma, Darren Edge, Leah Findlater, Hong Tan
The present study used a flat keyboard without moving keys and enabled with haptic keyclick feedback to examine the effect of haptic keyclick feedback on touch typing performance. We investigated how haptic keyclick feedback might improve typing performance in terms of typing speed, typing efficiency and typing errors. We found that haptic feedback increased typing speed and decreased typing errors compared to a condition without haptic feedback. Furthermore, the participants preferred auditory or haptic keyclick feedback to no feedback, and haptic feedback restricted to the typing finger alone is preferred to that over a larger area of the keyboard.
Seki Inoue, Yasutoshi Makino, Hiroyuki Shinoda
A method to present volumetric haptic objects in the air using spatial modulation of ultrasound is proposed. Previous methods of airborne ultrasonic tactile display were based on vibrotactile radiation pressure and sensor feedback systems, which result in low spatial receptive resolution. The proposed approach produces a spatially standing haptic image using stationary ultrasonic waves that enable users to actively touch 3D images without depending on vibrotactile stimulation and sensor feedback, which is a completely silent and free of the problems caused by feedback delay and errors. This paper evaluates our algorithm to synthesize a haptic holographic image and subjective experiments.
Colin Gallacher, John Willis, Jozsef Kovecses
In this study we investigate the role that the inertia tensor coupling has on user performance during navigational tasks. We also adapt the operation and admissible-motion space representation for haptic systems in which forces causing deviations from a desired path can be thought of as parasitic forces that degrade a users performance. Dynamic simulations were carried out to gain insight into the effects of navigating along paths of varying coupling using a 2DOF five-bar mechanism and were experimentally validated with a Quansar 2DOF Pantograph device.
Michael Lin Yang, Samuel Schorr, Iris Yan, Allison Okamura
During robot-assisted surgery, the absence of environment force sensing limits surgeons to rely on interaction forces between hand and manipulator to modulate the grip force applied on the environment. To determine the effect of master manipulator gripper stiffness on performance in a teleoperated task, we designed a open source gripper, the OmniGrip. The OmniGrip replaces the Phantom Omni's stylus and provides the ability for user programmable force characteristics. We conducted studies in which participants used an OmniGrip to teleoperate a Raven II in a pick-and-place task. Increasing the stiffness of the OmniGrip resulted in reduced interaction forces at the slave-side.
Alexander Russomanno, Brent Gillespie, Sile O'Modhrain, Mark Burns
We explore key design parameters for integrating fluidic logic and pneumatic actuators for a very-large shape display for application in braille and tactile graphics. We present a simple model of pressure-controlled flow valves, which are analogous to electric transistors. The model highlights a valve design that achieves noise immunity and enables signal propagation, both critical goals for creating fluidic logic circuits. Based on the pressure-controlled valve design, we built a pressure-based latching memory unit that can be integrated with pneumatic actuators to enable the control of an arbitrary number of tactile features with only a few external electronic control valves.
Evan Fakhoury, Peter Culmer, Brian Henson
This paper investigates the effect of maximum indentation force and depth on people's ability to accurately discriminate compliance using indirect visual information only. Participants took part in two psychophysical experiments where they were asked to choose the 'softest' sample from a series of presented sample pairs. Participants observed a computer-actuated tip indent the pairs to one of two conditions; maximum depth (10mm) or maximum force (4N). Results suggest that participants performed best in the task where they judged samples being indented to a pre-set maximum force. Moreover, our findings highlight the effect of visual information on compliance discrimination.
Clemens Schuwerk, Xiao Xu, Wolfgang Freund, Eckehard Steinbach
We describe a client-server architecture for haptic interaction with deformable objects. The object deformation is computed on the server and transmitted to the clients. There, an intermediate representation of the deformable object is used to locally render haptic force feedback displayed to the user. Based on a one-dimensional deformable object, we analyze the transparency of this architecture for a single client interaction. The delay introduced by the deformation simulation and the client-server communication leads to increased rendered forces at the clients. We propose a method that adaptively adjusts the stiffness used in the local force rendering to compensate for this.
Sebastian Merchel, M. Ercan Altinsoy, Anna Schwendicke
The examination of auditory intensity perception has a long history, and comprehensive knowledge exists. However, tactile intensity perception has not been studied as thoroughly. A short literature review provides an overview of the current state of research, with a focus on perceived vibration magnitude. To broaden our knowledge, tactile intensity perception was investigated further in this study. The growth of perceived intensity of seat vibrations with increasing vibration level was compared to auditory loudness. Therefore, a magnitude estimation experiment was performed. Curves of equal vibration intensity have been determined.
Mu Xu, Dangxiao Wang, Yuru Zhang, Jian Song, Dong Wu
Compared with single-modal sensorimotor task, cross-modal tasks are more complex. In this paper, we compared the performance of single and multi-sensory cues in single-modal and cross-modal tasks. The results showed that for single-modal task, the performance of using cross-modal cues was slightly worse than that of using single-sensory cues, which implied that the single-sensory cue was more suitable for the single-modal tasks while the multi-sensory cues might produce distraction to participants. For cross-modal control tasks, the multiple cues produced better performance than the single which implied that multi-sensory cues were more effective than the single when learning complex cross-modal tasks.
Adam Spiers, Harry Thompson, Anthony Pipe
Conventional haptic sensing technologies are impractical for clinical application to minimally invasive surgery, due to size, sterilization robustness and cost vs. tool disposability. In this work we validate the concept of remote force measurement, where force interactions at the tip of an EndoWrist surgical tool are observed via simple torque sensors near the tool's actuators. This method provides reusable sensors located outside of the human body, sidestepping many key issues that have limited practical haptic sensing in this scenario. The resulting unprocessed torque data indicates contact with synthetic soft tissue at various actuator velocities and during external shaft loading.
Yoshihiro Tanaka, Duy Phuong Nguyen, Tomohiro Fukuda, Akihito Sano
We developed a wearable tactile sensor for measuring skin vibrations using a polyvinylidene fluoride (PVDF) film, which is a polymer piezo material. The sensor allows users to touch with bare fingers and to conduct active touch, and detects skin-propagated vibrations when fingertip touches an object. A transfer function from vibrations applied on the fingertip to the sensor output was expressed by using a finger model, a sensor model, and an electric model of the PVDF film. Then, the measurement of the frequency response of the sensor, the estimation of vibrations, the sensor output for three different textures were tested.
Alvaro G. Perez, Daniel Lobo, Francesco Chinello, Gabriel Cirio, Monica Malvezzi, José San Martín, Domenico Prattichizzo, Miguel A. Otaduy
This paper introduces a tactile rendering algorithm for wearable cutaneous devices that stimulate the skin through local contact surface modulation. The first step in the algorithm simulates contact between a nonlinear skin model and virtual objects, and computes the contact surface to be rendered. The second step takes the desired contact surface as input, and computes the device configuration by solving an optimization problem, i.e., minimizing the deviation between the contact surface in the virtual environment and the contact surface rendered by the device. The method is implemented on a thimble-like wearable device.
Ehsan Noohi, Sina Parastegari, Milos Zefran
While hand trajectory has been successfully modeled for single arm reaching movement, few works have considered the bimanual reaching movement and no study has modeled the dyadic reaching movement. In this paper, we study both bimanual and dyadic reaching movements and show that the motion trajectory follows the minimum-jerk trajectory. To the best of our knowledge, this is the first work that studies the dyadic reaching movements. Furthermore, we show that our model is consistent with the existing theories on single arm motions, when applied to each of the cooperating arms.
Sunghoon Yim, Seokhee Jeon, Seungmoon Choi
This paper presents an extended data-driven haptic rendering method capable of reproducing force responses during sliding interaction on a large surface area. \ The core part of the approach is a set of input variables for data interpolation model training, which includes a proxy -- the contact point on a surface when undeformed. The behavior of the proxy is simulated in real-time based on a sliding yield surface -- a surface separating the sliding and the sticking area in the external force space. During rendering, the RBF based interpolation model using the proposed input variable set estimates force responses in real-time. \ \ \
Femke E. van Beek, Dennis J.F. Heck, Henk Nijmeijer, Wouter M. Bergmann Tiest, Astrid M.L. Kappers
In controlling teleoperation systems subject to communication delays, unstable behavior is often prevented by injecting damping. A proper perception of hardness is required to efficiently interact with objects, but it is unknown if injecting damping influences the perceived hardness of objects. To investigate this, participants compared the hardnesses of lightly and heavily damped objects, using tasks with and without free-air movement, while their movements were recorded. The results show that adding damping decreases the perceived hardness for the former task, while it increases perceived hardness for the latter task. This shows that damping influences perceived hardness in a task-specific way.
Anthony Chabrier, Franck Gonzalez, Florian Gosselin, Wael Bachta
Haptic interfaces aim at realistically simulating physical interactions within a Virtual Environment (VE) through the sense of touch. While this can be attained when interacting through a handle grasped in hand, this is much more difficult when considering dexterous interactions with manual interfaces or exoskeletons due to the high number of degrees of freedom and limited space available. This paper proposes a design methodology dedicated to such devices. It is shown that a device allowing to interact with the five fingertips and the side of the index allows interacting naturally within a VE more than 50% of the time.
Knut Drewing, Steffen Bruckbauer, Dora Szoke
When small holes are felt with the tongue they are perceived to be larger as compared to when felt with the finger. We hypothesize that differences in perceived size are due to differences in the effector's deformation at the edge of the explored hole, which correlate with the effector's pliability. Experiment I demonstrates that the tongue perceives holes to be larger when it exerts higher forces on the holes. Experiment II demonstrates that holes at the toe are perceived to be smaller than holes at the finger and considerably smaller than holes at the tongue. These findings corroborate our hypothesis.
Yongjae Yoo, Taekbeom Yoo, Jihyun Kong, Seungmoon Choi
This paper is concerned with the emotional responses of tactile icons. Using three sets of tactile icons in which four physical parameters-amplitude, frequency, duration, and envelope-were systematically varied, we estimated their valence and arousal scores in a perceptual experiment with 24 participants. Results showed that the four parameters have clear relationships to the emotional responses of tactile icons. Our tactile icons spanned to a large region in the valence-arousal space, but they did not elicit very positive-relaxing or very negative-relaxing emotional responses. These findings provide the design guidelines of tactile icons that have desired emotional properties.
Hasti Seifi, Kailun Zhang, Karon MacLean
With haptics commonplace in consumer devices, diverse user perception and aesthetic preferences confound haptic designers. End-user customization drawn from example sets is an obvious solution, but haptic collections are notoriously difficult to explore. This work addresses the provision of highly navigable access to large, diverse sets of vibrotactile stimuli, on the premise that multiple access pathways facilitate discovery and engagement. We propose and examine five organization schemes (taxonomies), describe how we created a 120-item VT library, and present and study VibViz, an interactive tool for end-user library navigation and our own investigation of how different taxonomies can assist navigation.
Amit Bhardwaj, Subhasis Chaudhuri
For the haptic transmission in a teleoperation, the temporal resolution Tr (minimum time spacing required in perceiving the jump discontinuity) \ needs also to be considered while effecting perceptually adaptive \ sampling. In this work, we propose a statistical method to estimate the temporal resolution Tr. In order to achieve this, we design an appropriate experimental set up, and record the haptic responses for several users extensively. We also study the effect of perceptual fatigue on the temporal resolution Tr, and validate all results using the classical psychometric approach.
Mohammadreza Motamedi, Jean-Philippe Roberge, Vincent Duchaine
This paper presents a robotic system that was used to study the restoration of touch sensitivity. Here, a combination of tactile sensors, robotic fingers, and a haptic interface enabled us to undertake different types of experiments on human subjects. To this end, we have conducted two separate tests on 8 human subjects in order to assess the effectiveness of the static and dynamic modalities in different detectable ranges of the skin sensitivity.
Uriel Martinez-Hernandez, Nathan F. Lepora, Tony J. Prescott
We present an intrinsic motivation approach for haptics in robotics. First, a probabilistic method is employed to reduce uncertainty present in tactile measurements. Second, tactile exploration is actively controlled by intelligently moving a robot hand towards interesting locations. The active behaviour performed with a robotic hand is achieved by an intrinsic motivation approach, which permitted to improve the accuracy over the results obtained with a fixed sequence of exploration movements. Our was validated in simulated and real environments with a three-fingered robotic hand. The results demonstrate that our method is robust and suitable for haptic perception in autonomous robotics.
Mounia Ziat, Andrea Savord, Ilja Frissen
Rumble strips (RS) offer ideal conditions for multimodality research. Designed to reduce crashes and alert drowsy or inattentive drivers, their effectiveness in crash reduction is not questioned but little is known regarding how information from tactile vibrations and auditory rumbling is integrated during low-vision driving conditions. In this paper, we report descriptive data related to participants' perceptual experience while driving on a RS road during a snow storm, as well as data collected from participants driving in a simulated snow storm environment, and suggest future research perspectives.
Heather Culbertson, Katherine Kuchenbecker
Dragging a tool across a textured surface produces vibrations that convey information about the surface qualities. These vibrations naturally depend on the tool's normal force and tangential speed, but virtual surface textures don't always mimic this behavior. We conducted a human-subject study to analyze the importance of creating virtual texture vibrations that respond to user force and speed. Removing speed responsiveness caused a significant decrease in realism, but removing force responsiveness did not. This result indicates that realistic virtual texture vibrations should vary with user speed but may not need to vary with user force.
Aghil Jafari, Muhammad Nabeel, Jee-Hwan Ryu
Our group have proposed Input-to-State Stable (ISS) approach, which reduces the design conservatism of the passivity-based controllers by allowing bigger output energy from the haptic interface compared with the passivity-based controller while guaranteeing the stability. This paper extends the ISS approach for multi-DoF haptic interaction. For multi-DoF haptic interaction, penetration depth-based rendering method using Virtual Proxy (VP) is adopted, and VP allows us to decouple the interaction into each axis. Then, we extend the previous one-port ISS approach to two-port ISS approach, and generalize this into multi-DoF ISS approach by augmenting each two-port analysis. \
Won-Hyeong Park, Tae-Heon Yang, Yongjae Yoo, Seungmoon Choi, Sang-Youn Kim
This paper presents a flexible and bendable vibrotactile actuator that can be easily applied to shape changing mobile devices. The proposed vibrotactile actuator is made with an electro-conductive membrane based on polyurethane, a base membrane, and an airgap. Actuation of the proposed actuator is controlled by a polarity of both charged membranes and the actuator performance can be modulated by increasing level of biased electric potential. We conducted a user experiment, and it shows that the proposed actuator can provide vibrations with sufficient strength for perception.
Fabio Tatti, Gabriel Baud-Bovy
The haptic modality is a direct and informative communication channel when manipulating objects jointly, but it may also be difficult to interpret. Indeed, the forces generated by the partner and the environment are summed together. This work uses techniques from psychophysics to investigate the ability of humans to untangle these two sources in a task where dyads had to identify the direction of a weak external force. We present a variety of force sharing strategies adopted by the dyads and their implications on the subjects' task performance.
Séréna Bochereau, Stephen Sinclair, Vincent Hayward
One human finger explored plastic Braille dots using a variety of velocity and force profiles. Characteristics of the interaction were studied to explore the interdependence of amplitude/duration across signals. Both amplitude, defined as maximum tangential force, and duration, varied with velocity and normal force, however the integral of the tangential force over time was independent of either variable. When three consecutive dots of varying height were examined, the tangential force integral increased in proportion to height. We propose that the nervous system may use this quantity as an invariant to recognise the same spatial asperity explored under different exploratory conditions.
Craig Shultz, Michael Peshkin, Ed Colgate
We present and discuss a nearly century old haptic effect with human fingertips. This effect, based on the 1923 work of Johnsen and Rahbek, is capable of producing DC electrostatic forces on the bare finger an order of magnitude larger than those previously reported in literature. We propose an electrical circuits based force model for this effect, drawn from research done concerning electrostatic chucking devices, and show how this model fits in with previous electrostatic force models. Through this discussion we aim to clarify the concept of electrovibration, and expand this concept to the more general principle of electroadhesion.
Rebecca Jarman, Balazs Janko, William Harwin
Small DC permanent magnet electric motors are commonly used as \ actuators in haptic devices and tend to spend a significant period of \ time in a `stalled' condition where they oppose an applied force. \ This paper identifies the relationship between heat loss and force \ generation for these haptic actuators. The work then presents results \ on current over-stressing of small DC motors so as to understand the \ risks of demagnetisation against thermal damage to the armature. \ Results indicate that it should be possible to apply short current \ over-stresses to commercial DC permanent magnet motors to increase end \ point force.
Jin Ryong Kim, Hong Z. Tan
We investigate the effect of information content in sensory feedback on typing performance using a flat keyboard. We evaluate and compare typing performance with key-press confirmation and key-correctness information through sensory feedback on the flat keyboard. Twelve participants are asked to touch-type randomly selected phrases under various combinations of visual, auditory and haptic sensory feedback conditions. The results show that typing speed is not significantly affected by the information content in sensory feedback, but the uncorrected error rate is significantly lower when key-correctness information is available. Our findings are useful for developing flat keyboards with assistive information through sensory feedback.
Anna Metzger, Knut Drewing
We investigated relative contributions of different haptic signals to softness perception. Subtle external vertical forces were transmitted to the human finger during the exploration of silicone-rubber stimuli to dissociate force estimates provided by kinesthetic signals and the efference copy from cutaneous force estimates. We measured Points of Subjective Equality of manipulated references to stimuli explored without external forces. PSEs shifted as a linear function of external force to higher compliances with pushing and to lower compliances with pulling force. The relative contribution of kinesthetic/efference copy information to perceived softness was 23% for rather hard and 29% for rather soft stimuli.
Caitlyn Seim, Tanya Estes, Thad Starner
Passive Haptic Learning (PHL) enables users to acquire motor skills by \ receiving tactile stimulation while no perceived attention is given to \ learning. Initial work used gloves with embedded vibration motors to \ passively teach users how to play simple, one-handed piano melodies. In an effort to create a more practical system for learning full piano pieces, we present research on Passive Haptic Learning.
Tobias Bützer, Bogdan Vigaru, Roger Gassert
Fiberoptic force sensors are commonly used in fMRI applications to measure interaction forces with subjects or reduce the inherent dynamics of a haptic interface trough force feedback. In this paper we propose a compact and integrated elastic probe for fiberoptics-based force sensing, developed using low-cost off-the-shelf 3D printing technology. Characterization of the sensor probe shows high linearity, repeatability and temporal stability, as well as high reproducibility in terms of the manufacturing process. The realized sensor is integrated into a linear grasper to evaluate its performance in force-feedback applications, underlining the potential of this technology for use in fMRI-compatible haptic interfaces.
Jan Smisek, Rene M. van Paassen, Andre Schiele
The purpose of this paper is to analyze the effects of inaccuracies of haptic guidance systems during execution of constrained tasks. The Lawrence teleoperation framework is extended in this paper by addition of an impedance type, position based attractive haptic guidance and analyzed from a control system perspective. We focus on systems where haptic guidance is used together with position or force based feedback. The effect of inaccurate guidance is discussed by using the proposed framework and quantified. Theoretical results are experimentally verified on a real haptic teleoperation setup.
Sunghwan Shin, Reza Haghighi Osgouei, Ki-Duk Kim, Seungmoon Choi
This paper presents a new approach for data-driven modeling and rendering of isotropic surface textures from contact acceleration data on the basis of frequency-decomposed neural networks. We propose two neural network models in different topologies, unified and decomposed, and experimentally evaluate their performance using the acceleration data collected by a motorized 2D texture scanner we developed. The modeling performance of the unified neural network model is shown comparable to the best available in the literature. We also provide preliminary but promising modeling results for anisotropic textures. \
Domenico Buongiorno, Michele Barsotti, Edoardo Sotgiu, Claudio Loconsole, Massimiliano solazzi, Vitoantonio Bevilacqua, Antonio Frisoli
The paper presents a myoelectric control of an arm exoskeleton designed for rehabilitation. A four-musclesbased NeuroMusculoSkeletal (NMS) model was implemented and optimized using genetic algorithms to adapt the model to different subjects. The NMS model is able to predict the shoulder and elbow torques which are used by the control algorithm to ensure a minimal force of interaction. \ \ The accuracy of the method is assessed through validation experiments conducted with two healthy subjects performing free movements along the pseudo-sagittal plane. The experiments show promising results for our approach showing its potential for being introduced in a rehabilitation protocol.
Hendrik Börner, Satoshi Endo, Antonio Frisoli, Sandra Hirche
This paper investigates the effects of vibrotactile stimulus designs for spatially guiding a user in time-critical dynamical tasks. We contrast two types of vibrotactile stimulus, representing either optimal hand velocity or acceleration for the stabilization of an inverted pendulum. The analyses of the participants' stabilization and learning behavior revealed a significant improvement in performance caused by additional velocity-dependent feedback, likely due to more efficient processing for the velocity-dependent motor guidance in the central nervous system. This study suggests how human-centric vibrotactile stimuli should be designed and how they can be effectively transmitted to the human user for time-critical behavioral guidance.
Daniele Leonardis, Massimiliano Solazzi, Ilaria Bortone, Antonio Frisoli
A novel wearable haptic device for modulating skin stretch at the fingertip is presented. Rendering of skin stretch in 3 degrees of freedom, with contact - no contact capabilities, was implemented through rigid parallel kinematics. The novel 3-RSR configuration allowed compact dimensions with minimum encumbrance of the hand workspace and minimum inter-finger interference. A differential method for solving the non-trivial inverse kinematics is proposed and implemented in real time for controlling the device. Experimental results showed that participants performed a virtual grasping task more precisely and with grasping forces closer to the expected natural behavior with the provided haptic feedback.
Oleg Špakov, Jussi Rantala, Poika Isokoski
Haptic stimulation appears as a promising feedback channel for non-visual feedback related to gaze events and helps monitoring the tracking accuracy when using mobile eye-tracking device. Short repetitive vibrations from four actuators applied to the head and neck of the user were tested in this context and compared to the back that has often been used for cueing in other studies. The results showed that 1) the haptic stimulation on the head and neck cues users as efficiently as the stimulation of the back, and 2) sequential activation of multiple actuators is more appropriate for cuing gaze than simultaneous activation.
Matteo Bianchi, Mattia Poggiani, Alessandro Serio, Antonio Bicchi
This work presents FYD-pad, a fabric-based yielding tactile display for softness and texture rendering. The system exploits the control of two motors to modify both the stretching state of the elastic fabric for softness rendering and to convey texture information on the basis of accelerometer-based data. At the same time, the measurement of the contact area can be used to control remote or virtual robots. In this paper, we discuss the architecture of FYD-pad and the techniques used for softness and texture reproduction as well as experiments with humans to show the effectiveness of the device in delivering tactile information.
Ginga Kato, Yoshihiro Kuroda, Ilana Nisky, Kiyoshi Kiyokawa, Haruo Takemura
Force feedback in tool-mediated interactions with \ the environment is important for successful performance of \ complex tasks. Stylus-based haptic devices are studied and used \ extensively, and most of these devices require either grounding \ or attachment to the body of the user. In this paper, \ we propose a novel method to represent the vertical forces that \ are applied on the tip of a tool using a non-grounded rotation \ mechanism by mimicking the cutaneous sensation caused \ by these forces. To evaluate this method, we develop a novel \ chopaticks-type haptic device that renders the \ sensation of manipulating objects using tools.
Teng Li, Dangxiao Wang, Shusheng Zhang, Yuru Zhang, Chun Yu
In this paper, human's capability to control absolute magnitudes of fingertip force under audio or visual feedback was observed. Twelve participants applied a target force by pressing a force sensor with their fingers and maintained the force within various specified tolerances for a certain duration. The results showed that the applied fingertip force obeyed Fitts' law in both visual and auditory feedback modes when the index of difficulty was smaller than a threshold. This may be used as guidelines for the applications that rely on accurate and quick changing force control over a target region such as multiple tapping tasks.
Thomas Sednaoui, Eric Vezzoli, Brigida Dzidek, Betty Lemaire-Semail, Cedrick Chappaz, Michael Adams
Previously proposed models of the ultrasonic lubrication of a finger mediated by flat surfaces are not consistent with the experimental results for vibrational amplitudes greater than a few microns. This paper presents experimental data acquired through a dedicated passive touch tribometer and compares it with existing model of squeeze film lubrication. Considering the large difference between analytic and experimental results an experimental model of ultrasonic lubrication at high vibrational amplitudes is then proposed.
Farah Arab, Sabrina Panëels, Margarita Anastassova, Stéphanie Cœugnet, Fanny Le Morellec, Aurélie Dommes, Aline Chevalier
Haptic technologies can open up new avenues for assisting older people in their daily activities, in particular for navigation. However, older adults' specific needs for a haptic navigation aid have seldom been investigated, nor for the design of haptic patterns that would be both acceptable and efficient for them. This paper contributes to this challenge through a user evaluation that was conducted to assess patterns, designed for and by the elderly, during a navigation task in an urban environment. The results led to a number of recommendations for the design of haptic patterns adapted to the older adults' needs.
Moria Fisher, Felix Huang, Verena Klamroth-Marganska, Robert Riener, James Patton
Error feedback is critical for supporting motor adaptation in skilled tasks. Error augmentation interventions, in which participants' errors are amplified during training, have shown success over repetitive practice. Here we show that the statistical error tendencies can inform the design of customized error augmentation training forces. We hypothesized that with customized error augmentation participants will adapt faster to learning a visual-motor distortion and have greater improvement than participants receiving standard error augmentation. We found that participants receiving customized forces adapted faster and consequently changed with smaller forces. These promising results support the need for customization to target subject specific errors.
Athanasia Moungou, Jean-Louis Thonnard, André Mouraux
When sliding our fingertip on a surface, complex vibrations are produced in the skin. In the present study, we used electroencephalography (EEG) to record steady-state evoked brain potentials (SS-EPs) and characterize the cortical activity related to the passive tactile exploration of textured surfaces. Using square-wave gratings of different spatial period (SP), ranging from coarse to smooth, and a sinusoidal grating with a glued fabric on it, we expected that these stimuli would elicit SS-EPs at different frequencies depending on the SP. Our results suggest that SS-EPs could be used to study the brain responses regarding the tactile exploration of textures.
Stefano Papetti, Hanna Järveläinen, Gian-Marco Schmid
An experiment was performed to study the effect of actively applied forces on vibrotactile thresholds. The task consisted in pressing the fingertip against a flat rigid surface which provided broadband vibration noise of varying amplitude. \ Possibly due to the concurrent effect of large contact area, spectrally complex stimuli and active pressing force, the measured sensitivity thresholds are considerably lower than what is found in most of the previous literature. Moreover, significant differences in thresholds were found between the lowest and middle force level, and the highest and middle force level.
Laszlo Kovacs, Jozsef Kovecses
In the dynamic analysis of haptic systems the human operator is often neglected and only the uncoupled device is investigated. When considered, the human model is typically represented by passive impedance elements employing simple mass-spring-damper representations. The dynamics of coupled systems with multiple degrees-of-freedom device- and human operator models have not been much investigated. In the present paper, we discuss reduced order dynamic representations for such complex models. We also consider the coupled system, and demonstrate the effect of the human operator on the combined dynamics. Structural flexibility, different grasping conditions, and active human stabilization with reflex delay are considered.
Christian Hatzfeld, Mario Kupnik, Roland Werthschützky
This work shows an implementation of Psi and UML psychometric methods to unforced choice paradigms. These paradigms have shown a similar performance to forced choice paradigms but are expected to create less confusion for test subjects for low stimuli intensities. An implementation of an unsure test person is presented. Psi and UML methods are compared to the UWUD method, Variation Coefficient and the Sweat Factor are considered as measures for repeatability and efficiency and the threshold bias is used for evaluation of the accuracy. Based on the simulation results, both methods seem suitable to be combined with unforced choice paradigms.