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Sample records for haptic curvature contrast

  1. Memory for curvature of objects: haptic touch vs. vision.

    Science.gov (United States)

    Ittyerah, Miriam; Marks, Lawrence E

    2007-11-01

    The present study examined the role of vision and haptics in memory for stimulus objects that vary along the dimension of curvature. Experiment 1 measured haptic-haptic (T-T) and haptic-visual (T-V) discrimination of curvature in a short-term memory paradigm, using 30-second retention intervals containing five different interpolated tasks. Results showed poorest performance when the interpolated tasks required spatial processing or movement, thereby suggesting that haptic information about shape is encoded in a spatial-motor representation. Experiment 2 compared visual-visual (V-V) and visual-haptic (V-T) short-term memory, again using 30-second delay intervals. The results of the ANOVA failed to show a significant effect of intervening activity. Intra-modal visual performance and cross-modal performance were similar. Comparing the four modality conditions (inter-modal V-T, T-V; intra-modal V-V, T-T, by combining the data of Experiments 1 and 2), in a global analysis, showed a reliable interaction between intervening activity and experiment (modality). Although there appears to be a general tendency for spatial and movement activities to exert the most deleterious effects overall, the patterns are not identical when the initial stimulus is encoded haptically (Experiment 1) and visually (Experiment 2).

  2. Haptic perception of object curvature in Parkinson's disease.

    Directory of Open Access Journals (Sweden)

    Jürgen Konczak

    2008-07-01

    Full Text Available The haptic perception of the curvature of an object is essential for adequate object manipulation and critical for our guidance of actions. This study investigated how the ability to perceive the curvature of an object is altered by Parkinson's disease (PD.Eight healthy subjects and 11 patients with mild to moderate PD had to judge, without vision, the curvature of a virtual "box" created by a robotic manipulandum. Their hands were either moved passively along a defined curved path or they actively explored the curved curvature of a virtual wall. The curvature was either concave or convex (bulging to the left or right and was judged in two locations of the hand workspace--a left workspace location, where the curved hand path was associated with curved shoulder and elbow joint paths, and a right workspace location in which these joint paths were nearly linear. After exploring the curvature of the virtual object, subjects had to judge whether the curvature was concave or convex. Based on these data, thresholds for curvature sensitivity were established. The main findings of the study are: First, 9 out 11 PD patients (82% showed elevated thresholds for detecting convex curvatures in at least one test condition. The respective median threshold for the PD group was increased by 343% when compared to the control group. Second, when distal hand paths became less associated with proximal joint paths (right workspace, haptic acuity was reduced substantially in both groups. Third, sensitivity to hand trajectory curvature was not improved during active exploration in either group.Our data demonstrate that PD is associated with a decreased acuity of the haptic sense, which may occur already at an early stage of the disease.

  3. Integration of length and curvature in haptic perception

    NARCIS (Netherlands)

    Panday, V.; Bergmann Tiest, W.M.; Kappers, A.M.L.

    2014-01-01

    We investigated if and how length and curvature information are integrated when an object is explored in one hand. Subjects were asked to explore four types of objects between thumb and index finger. Objects differed in either length, curvature, both length and curvature correlated as in a circle,

  4. Integration of length and curvature in haptic perception.

    Science.gov (United States)

    Panday, Virjanand; Tiest, Wouter M Bergmann; Kappers, Astrid M L

    2014-01-24

    We investigated if and how length and curvature information are integrated when an object is explored in one hand. Subjects were asked to explore four types of objects between thumb and index finger. Objects differed in either length, curvature, both length and curvature correlated as in a circle, or anti-correlated. We found that when both length and curvature are present, performance is significantly better than when only one of the two cues is available. Therefore, we conclude that there is integration of length and curvature. Moreover, if the two cues are correlated in a circular cross-section instead of in an anti-correlated way, performance is better than predicted by a combination of two independent cues. We conclude that integration of curvature and length is highly efficient when the cues in the object are combined as in a circle, which is the most common combination of curvature and length in daily life.

  5. The effects of curvature on haptic judgments of extent in sighted and blind people

    NARCIS (Netherlands)

    Heller, Morton A.; Kappers, Astrid M L; McCarthy, Melissa; Clark, Ashley; Riddle, Tara; Fulkerson, Erin; Wemple, Lindsay; Walk, Anne McClure; Basso, Andreana; Wanek, Crystal; Russler, Kristen

    2008-01-01

    A series of experiments was carried out to examine the effect of curvature on haptic judgments of extent in sighted and blind individuals. Experiment 1 showed that diameters connecting the endpoints of semicircular lines were underestimated with respect to straight lines, but failed to show an

  6. What you can't feel won't hurt you: Evaluating haptic hardware using a haptic contrast sensitivity function.

    Science.gov (United States)

    Salisbury, C M; Gillespie, R B; Tan, H Z; Barbagli, F; Salisbury, J K

    2011-01-01

    In this paper, we extend the concept of the contrast sensitivity function - used to evaluate video projectors - to the evaluation of haptic devices. We propose using human observers to determine if vibrations rendered using a given haptic device are accompanied by artifacts detectable to humans. This determination produces a performance measure that carries particular relevance to applications involving texture rendering. For cases in which a device produces detectable artifacts, we have developed a protocol that localizes deficiencies in device design and/or hardware implementation. In this paper, we present results from human vibration detection experiments carried out using three commercial haptic devices and one high performance voice coil motor. We found that all three commercial devices produced perceptible artifacts when rendering vibrations near human detection thresholds. Our protocol allowed us to pinpoint the deficiencies, however, and we were able to show that minor modifications to the haptic hardware were sufficient to make these devices well suited for rendering vibrations, and by extension, the vibratory components of textures. We generalize our findings to provide quantitative design guidelines that ensure the ability of haptic devices to proficiently render the vibratory components of textures.

  7. 3D skin surface reconstruction from a single image by merging global curvature and local texture using the guided filtering for 3D haptic palpation.

    Science.gov (United States)

    Lee, K; Kim, M; Kim, K

    2018-05-11

    Skin surface evaluation has been studied using various imaging techniques. However, all these studies had limited impact because they were performed using visual exam only. To improve on this scenario with haptic feedback, we propose 3D reconstruction of the skin surface using a single image. Unlike extant 3D skin surface reconstruction algorithms, we utilize the local texture and global curvature regions, combining the results for reconstruction. The first entails the reconstruction of global curvature, achieved by bilateral filtering that removes noise on the surface while maintaining the edge (ie, furrow) to obtain the overall curvature. The second entails the reconstruction of local texture, representing the fine wrinkles of the skin, using an advanced form of bilateral filtering. The final image is then composed by merging the two reconstructed images. We tested the curvature reconstruction part by comparing the resulting curvatures with measured values from real phantom objects while local texture reconstruction was verified by measuring skin surface roughness. Then, we showed the reconstructed result of our proposed algorithm via the reconstruction of various real skin surfaces. The experimental results demonstrate that our approach is a promising technology to reconstruct an accurate skin surface with a single skin image. We proposed 3D skin surface reconstruction using only a single camera. We highlighted the utility of global curvature, which has not been considered important in the past. Thus, we proposed a new method for 3D reconstruction that can be used for 3D haptic palpation, dividing the concepts of local and global regions. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  8. Haptic perception

    NARCIS (Netherlands)

    Kappers, A.M.L.; Bergmann Tiest, W.M.

    2013-01-01

    Fueled by novel applications, interest in haptic perception is growing. This paper provides an overview of the state of the art of a number of important aspects of haptic perception. By means of touch we can not only perceive quite different material properties, such as roughness, compliance,

  9. Clinical and optical intraocular performance of rotationally asymmetric multifocal IOL plate-haptic design versus C-loop haptic design.

    Science.gov (United States)

    Alió, Jorge L; Plaza-Puche, Ana B; Javaloy, Jaime; Ayala, María José; Vega-Estrada, Alfredo

    2013-04-01

    To compare the visual and intraocular optical quality outcomes with different designs of the refractive rotationally asymmetric multifocal intraocular lens (MFIOL) (Lentis Mplus; Oculentis GmbH, Berlin, Germany) with or without capsular tension ring (CTR) implantation. One hundred thirty-five consecutive eyes of 78 patients with cataract (ages 36 to 82 years) were divided into three groups: 43 eyes implanted with the C-Loop haptic design without CTR (C-Loop haptic only group); 47 eyes implanted with the C-Loop haptic design with CTR (C-Loop haptic with CTR group); and 45 eyes implanted with the plate-haptic design (plate-haptic group). Visual acuity, contrast sensitivity, defocus curve, and ocular and intraocular optical quality were evaluated at 3 months postoperatively. Significant differences in the postoperative sphere were found (P = .01), with a more myopic postoperative refraction for the C-Loop haptic only group. No significant differences were detected in photopic and scotopic contrast sensitivity among groups (P ⩾ .05). Significantly better visual acuities were present in the C-Loop haptic with CTR group for the defocus levels of -2.0, -1.5, -1.0, and -0.50 D (P ⩽.03). Statistically significant differences among groups were found in total intraocular root mean square (RMS), high-order intraocular RMS, and intraocular coma-like RMS aberrations (P ⩽.04), with lower values from the plate-haptic group. The plate-haptic design and the C-Loop haptic design with CTR implantation both allow good visual rehabilitation. However, better refractive predictability and intraocular optical quality was obtained with the plate-haptic design without CTR implantation. The plate-haptic design seems to be a better design to support rotational asymmetric MFIOL optics. Copyright 2013, SLACK Incorporated.

  10. Pantomime-grasping: Advance knowledge of haptic feedback availability supports an absolute visuo-haptic calibration

    Directory of Open Access Journals (Sweden)

    Shirin eDavarpanah Jazi

    2016-05-01

    Full Text Available An emerging issue in movement neurosciences is whether haptic feedback influences the nature of the information supporting a simulated grasping response (i.e., pantomime-grasping. In particular, recent work by our group contrasted pantomime-grasping responses performed with (i.e., PH+ trials and without (i.e., PH- trials terminal haptic feedback in separate blocks of trials. Results showed that PH- trials were mediated via relative visual information. In contrast, PH+ trials showed evidence of an absolute visuo-haptic calibration – a finding attributed to an error signal derived from a comparison between expected and actual haptic feedback (i.e., an internal forward model. The present study examined whether advanced knowledge of haptic feedback availability influences the aforementioned calibration process. To that end, PH- and PH+ trials were completed in separate blocks (i.e., the feedback schedule used in our group’s previous study and a block wherein PH- and PH+ trials were randomly interleaved on a trial-by-trial basis (i.e., random feedback schedule. In other words, the random feedback schedule precluded participants from predicting whether haptic feedback would be available at the movement goal location. We computed just-noticeable-difference (JND values to determine whether responses adhered to, or violated, the relative psychophysical principles of Weber’s law. Results for the blocked feedback schedule replicated our group’s previous work, whereas in the random feedback schedule PH- and PH+ trials were supported via relative visual information. Accordingly, we propose that a priori knowledge of haptic feedback is necessary to support an absolute visuo-haptic calibration. Moreover, our results demonstrate that the presence and expectancy of haptic feedback is an important consideration in contrasting the behavioral and neural properties of natural and stimulated (i.e., pantomime-grasping grasping.

  11. Comparison of grey matter volume and thickness for analysing cortical changes in chronic schizophrenia: a matter of surface area, grey/white matter intensity contrast, and curvature.

    Science.gov (United States)

    Kong, Li; Herold, Christina J; Zöllner, Frank; Salat, David H; Lässer, Marc M; Schmid, Lena A; Fellhauer, Iven; Thomann, Philipp A; Essig, Marco; Schad, Lothar R; Erickson, Kirk I; Schröder, Johannes

    2015-02-28

    Grey matter volume and cortical thickness are the two most widely used measures for detecting grey matter morphometric changes in various diseases such as schizophrenia. However, these two measures only share partial overlapping regions in identifying morphometric changes. Few studies have investigated the contributions of the potential factors to the differences of grey matter volume and cortical thickness. To investigate this question, 3T magnetic resonance images from 22 patients with schizophrenia and 20 well-matched healthy controls were chosen for analyses. Grey matter volume and cortical thickness were measured by VBM and Freesurfer. Grey matter volume results were then rendered onto the surface template of Freesurfer to compare the differences from cortical thickness in anatomical locations. Discrepancy regions of the grey matter volume and thickness where grey matter volume significantly decreased but without corresponding evidence of cortical thinning involved the rostral middle frontal, precentral, lateral occipital and superior frontal gyri. Subsequent region-of-interest analysis demonstrated that changes in surface area, grey/white matter intensity contrast and curvature accounted for the discrepancies. Our results suggest that the differences between grey matter volume and thickness could be jointly driven by surface area, grey/white matter intensity contrast and curvature. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  12. Haptic exploration of fingertip-sized geometric features using a multimodal tactile sensor

    Science.gov (United States)

    Ponce Wong, Ruben D.; Hellman, Randall B.; Santos, Veronica J.

    2014-06-01

    Haptic perception remains a grand challenge for artificial hands. Dexterous manipulators could be enhanced by "haptic intelligence" that enables identification of objects and their features via touch alone. Haptic perception of local shape would be useful when vision is obstructed or when proprioceptive feedback is inadequate, as observed in this study. In this work, a robot hand outfitted with a deformable, bladder-type, multimodal tactile sensor was used to replay four human-inspired haptic "exploratory procedures" on fingertip-sized geometric features. The geometric features varied by type (bump, pit), curvature (planar, conical, spherical), and footprint dimension (1.25 - 20 mm). Tactile signals generated by active fingertip motions were used to extract key parameters for use as inputs to supervised learning models. A support vector classifier estimated order of curvature while support vector regression models estimated footprint dimension once curvature had been estimated. A distal-proximal stroke (along the long axis of the finger) enabled estimation of order of curvature with an accuracy of 97%. Best-performing, curvature-specific, support vector regression models yielded R2 values of at least 0.95. While a radial-ulnar stroke (along the short axis of the finger) was most helpful for estimating feature type and size for planar features, a rolling motion was most helpful for conical and spherical features. The ability to haptically perceive local shape could be used to advance robot autonomy and provide haptic feedback to human teleoperators of devices ranging from bomb defusal robots to neuroprostheses.

  13. Salient features in 3-D haptic shape perception

    NARCIS (Netherlands)

    Plaisier, Myrthe A; Bergmann Tiest, Wouter M.; Kappers, Astrid M L

    2009-01-01

    Shape is an important cue for recognizing an object by touch. Several features, such as edges, curvature, surface area, and aspect ratio, are associated with 3-D shape. To investigate the saliency of 3-D shape features, we developed a haptic search task. The target and distractor items consisted of

  14. The Hedonic Haptic Player

    DEFF Research Database (Denmark)

    Vallgårda, Anna; Boer, Laurens; Cahill, Ben

    2017-01-01

    In this design case we present the Hedonic Haptic Player—a wearable device that plays different patterns of vibrations on the body as a form of music for the skin. With this we begin to explore the enjoyability of vibrations in a wearable set-up. Instead of implementing vibrations as a haptic...... output for some form of communication we want to explore their hedonistic value. The process leading up to the Hedonic Haptic player served as a first step in getting a grasp of the design space of vibrotactile stimuli in a broader sense. This is reported as seven episodes of explorations. The Hedonic...

  15. High Fidelity Haptic Rendering

    CERN Document Server

    Otaduy, Miguel A

    2006-01-01

    The human haptic system, among all senses, provides unique and bidirectional communication between humans and their physical environment. Yet, to date, most human-computer interactive systems have focused primarily on the graphical rendering of visual information and, to a lesser extent, on the display of auditory information. Extending the frontier of visual computing, haptic interfaces, or force feedback devices, have the potential to increase the quality of human-computer interaction by accommodating the sense of touch. They provide an attractive augmentation to visual display and enhance t

  16. Haptic Discrimination of Distance

    Science.gov (United States)

    van Beek, Femke E.; Bergmann Tiest, Wouter M.; Kappers, Astrid M. L.

    2014-01-01

    While quite some research has focussed on the accuracy of haptic perception of distance, information on the precision of haptic perception of distance is still scarce, particularly regarding distances perceived by making arm movements. In this study, eight conditions were measured to answer four main questions, which are: what is the influence of reference distance, movement axis, perceptual mode (active or passive) and stimulus type on the precision of this kind of distance perception? A discrimination experiment was performed with twelve participants. The participants were presented with two distances, using either a haptic device or a real stimulus. Participants compared the distances by moving their hand from a start to an end position. They were then asked to judge which of the distances was the longer, from which the discrimination threshold was determined for each participant and condition. The precision was influenced by reference distance. No effect of movement axis was found. The precision was higher for active than for passive movements and it was a bit lower for real stimuli than for rendered stimuli, but it was not affected by adding cutaneous information. Overall, the Weber fraction for the active perception of a distance of 25 or 35 cm was about 11% for all cardinal axes. The recorded position data suggest that participants, in order to be able to judge which distance was the longer, tried to produce similar speed profiles in both movements. This knowledge could be useful in the design of haptic devices. PMID:25116638

  17. Haptic discrimination of distance.

    Directory of Open Access Journals (Sweden)

    Femke E van Beek

    Full Text Available While quite some research has focussed on the accuracy of haptic perception of distance, information on the precision of haptic perception of distance is still scarce, particularly regarding distances perceived by making arm movements. In this study, eight conditions were measured to answer four main questions, which are: what is the influence of reference distance, movement axis, perceptual mode (active or passive and stimulus type on the precision of this kind of distance perception? A discrimination experiment was performed with twelve participants. The participants were presented with two distances, using either a haptic device or a real stimulus. Participants compared the distances by moving their hand from a start to an end position. They were then asked to judge which of the distances was the longer, from which the discrimination threshold was determined for each participant and condition. The precision was influenced by reference distance. No effect of movement axis was found. The precision was higher for active than for passive movements and it was a bit lower for real stimuli than for rendered stimuli, but it was not affected by adding cutaneous information. Overall, the Weber fraction for the active perception of a distance of 25 or 35 cm was about 11% for all cardinal axes. The recorded position data suggest that participants, in order to be able to judge which distance was the longer, tried to produce similar speed profiles in both movements. This knowledge could be useful in the design of haptic devices.

  18. Haptic perception of wetness

    NARCIS (Netherlands)

    Bergmann Tiest, W.M.; Kosters, N.D.; Daanen, H.A.M.; Kappers, A.M.L.

    2011-01-01

    The sensation of wetness is well-known but barely investigated. There are no specific wetness receptors in the skin, but the sensation is mediated by temperature and pressure perception. In our study, we have measured discrimination thresholds for the haptic perception of wetness of three di erent

  19. Haptic perception of wetness

    NARCIS (Netherlands)

    Bergmann Tiest, W.M.; Dolfine Kosters, N.; Daanen, h.a.m.; Kappers, A.M.L.

    2012-01-01

    In daily life, people interact with textiles of different degrees of wetness, but little is known about the me-chanics of wetness perception. This paper describes an experiment with six conditions regarding haptic dis-crimination of the wetness of fabrics. Three materials were used: cotton wool,

  20. Haptic perception of wetness

    NARCIS (Netherlands)

    Bergmann Tiest, W.M.; Kosters, N.D.; Kappers, Astrid M.L.; Daanen, H.A.M.

    2012-01-01

    In daily life, people interact with textiles of different degrees of wetness, but little is known about the mechanics of wetness perception. This paper describes an experiment with six conditions regarding haptic discrimination of the wetness of fabrics. Three materials were used: cotton wool,

  1. Pervasive haptics science, design, and application

    CERN Document Server

    Saga, Satoshi; Konyo, Masashi

    2016-01-01

    This book examines the state of the art in diverse areas of haptics (touch)-related research, including the psychophysics and neurophysiology of haptics, development of haptics displays and sensors, and applications to a wide variety of fields such as industry, education, therapy, medicine, and welfare for the visually impaired. It also discusses the potential of future haptics interaction, such as haptics for emotional control and remote haptics communication. The book offers a valuable resource not only for haptics and human interface researchers, but also for developers and designers at manufacturing corporations and in the entertainment industries.

  2. Haptic teleoperation systems signal processing perspective

    CERN Document Server

    Lee, Jae-young

    2015-01-01

    This book examines the signal processing perspective in haptic teleoperation systems. This text covers the topics of prediction, estimation, architecture, data compression, and error correction that can be applied to haptic teleoperation systems. The authors begin with an overview of haptic teleoperation systems, then look at a Bayesian approach to haptic teleoperation systems. They move onto a discussion of haptic data compression, haptic data digitization and forward error correction.   ·         Presents haptic data prediction/estimation methods that compensate for unreliable networks   ·         Discusses haptic data compression that reduces haptic data size over limited network bandwidth and haptic data error correction that compensate for packet loss problem   ·         Provides signal processing techniques used with existing control architectures.

  3. Virtual reality haptic dissection.

    Science.gov (United States)

    Erolin, Caroline; Wilkinson, Caroline; Soames, Roger

    2011-12-01

    This project aims to create a three-dimensional digital model of the human hand and wrist which can be virtually 'dissected' through a haptic interface. Tissue properties will be added to the various anatomical structures to replicate a realistic look and feel. The project will explore the role of the medical artist, and investigate cross-discipline collaborations in the field of virtual anatomy. The software will be used to train anatomy students in dissection skills, before experience on a real cadaver. The effectiveness of the software will be evaluated and assessed both quantitatively as well as qualitatively.

  4. Visual and Haptic Mental Rotation

    Directory of Open Access Journals (Sweden)

    Satoshi Shioiri

    2011-10-01

    Full Text Available It is well known that visual information can be retained in several types of memory systems. Haptic information can also be retained in a memory because we can repeat a hand movement. There may be a common memory system for vision and action. On the one hand, it may be convenient to have a common system for acting with visual information. On the other hand, different modalities may have their own memory and use retained information without transforming specific to the modality. We compared memory properties of visual and haptic information. There is a phenomenon known as mental rotation, which is possibly unique to visual representation. The mental rotation is a phenomenon where reaction time increases with the angle of visual target (eg,, a letter to identify. The phenomenon is explained by the difference in time to rotate the representation of the target in the visual sytem. In this study, we compared the effect of stimulus angle on visual and haptic shape identification (two-line shapes were used. We found that a typical effect of mental rotation for the visual stimulus. However, no such effect was found for the haptic stimulus. This difference cannot be explained by the modality differences in response because similar difference was found even when haptical response was used for visual representation and visual response was used for haptic representation. These results indicate that there are independent systems for visual and haptic representations.

  5. Haptics in periodontics

    Directory of Open Access Journals (Sweden)

    Savita Abdulpur Mallikarjun

    2014-01-01

    Full Text Available Throughout history, education has evolved, and new teaching/learning methods have been developed. These methods have helped us come a long way in understanding the pathogenesis, diagnosis, and treatment of diseases of the oral cavity. However, there is still no one good way to render a student/clinician the tactile sense for detecting calculus/caries or placing the incisions or detecting the smoothness of a restoration or any treatment procedures before entering the clinics. In the education field, to improve the tactile sensation, the sense of touch and force-feedback can offer great improvements to the existing learning methods, thus enhancing the quality of education procedures. The concept of Haptics, which is extensively in use and indispensable in other fields like aviation, telecommunication etc., is now making its way into dentistry. Against this background, the following write-up intends to provide a glimpse of the coming wave of Haptics - A virtual reality system in dental education and discusses the strengths and weak points of this system.

  6. Active skin as new haptic interface

    Science.gov (United States)

    Vuong, Nguyen Huu Lam; Kwon, Hyeok Yong; Chuc, Nguyen Huu; Kim, Duksang; An, Kuangjun; Phuc, Vuong Hong; Moon, Hyungpil; Koo, Jachoon; Lee, Youngkwan; Nam, Jae-Do; Choi, Hyouk Ryeol

    2010-04-01

    In this paper, we present a new haptic interface, called "active skin", which is configured with a tactile sensor and a tactile stimulator in single haptic cell, and multiple haptic cells are embedded in a dielectric elastomer. The active skin generates a wide variety of haptic feel in response to the touch by synchronizing the sensor and the stimulator. In this paper, the design of the haptic cell is derived via iterative analysis and design procedures. A fabrication method dedicated to the proposed device is investigated and a controller to drive multiple haptic cells is developed. In addition, several experiments are performed to evaluate the performance of the active skin.

  7. Haptics for Virtual Reality and Teleoperation

    CERN Document Server

    Mihelj, Matjaž

    2012-01-01

    This book covers all topics relevant for the design of haptic interfaces and teleoperation systems. The book provides the basic knowledge required for understanding more complex approaches and more importantly it introduces all issues that must be considered for designing efficient and safe haptic interfaces. Topics covered in this book provide insight into all relevant components of a haptic system. The reader is guided from understanding the virtual reality concept to the final goal of being able to design haptic interfaces for specific tasks such as nanomanipulation.  The introduction chapter positions the haptic interfaces within the virtual reality context. In order to design haptic interfaces that will comply with human capabilities at least basic understanding of human sensors-motor system is required. An overview of this topic is provided in the chapter related to human haptics. The book does not try to introduce the state-of-the-art haptic interface solutions because these tend to change quickly. On...

  8. Mobile Haptic Technology Development through Artistic Exploration

    DEFF Research Database (Denmark)

    Cuartielles, David; Göransson, Andreas; Olsson, Tony

    2012-01-01

    This paper investigates how artistic explorations can be useful for the development of mobile haptic technology. It presents an alternative framework of design for wearable haptics that contributes to the building of haptic communities outside specialized research contexts. The paper also present...

  9. Integrating 3D seismic curvature and curvature gradient attributes for fracture characterization: Methodologies and interpretational implications

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Dengliang

    2013-03-01

    In 3D seismic interpretation, curvature is a popular attribute that depicts the geometry of seismic reflectors and has been widely used to detect faults in the subsurface; however, it provides only part of the solutions to subsurface structure analysis. This study extends the curvature algorithm to a new curvature gradient algorithm, and integrates both algorithms for fracture detection using a 3D seismic test data set over Teapot Dome (Wyoming). In fractured reservoirs at Teapot Dome known to be formed by tectonic folding and faulting, curvature helps define the crestal portion of the reservoirs that is associated with strong seismic amplitude and high oil productivity. In contrast, curvature gradient helps better define the regional northwest-trending and the cross-regional northeast-trending lineaments that are associated with weak seismic amplitude and low oil productivity. In concert with previous reports from image logs, cores, and outcrops, the current study based on an integrated seismic curvature and curvature gradient analysis suggests that curvature might help define areas of enhanced potential to form tensile fractures, whereas curvature gradient might help define zones of enhanced potential to develop shear fractures. In certain fractured reservoirs such as at Teapot Dome where faulting and fault-related folding contribute dominantly to the formation and evolution of fractures, curvature and curvature gradient attributes can be potentially applied to differentiate fracture mode, to predict fracture intensity and orientation, to detect fracture volume and connectivity, and to model fracture networks.

  10. The curvature coordinate system

    DEFF Research Database (Denmark)

    Almegaard, Henrik

    2007-01-01

    The paper describes a concept for a curvature coordinate system on regular curved surfaces from which faceted surfaces with plane quadrangular facets can be designed. The lines of curvature are used as parametric lines for the curvature coordinate system on the surface. A new conjugate set of lin...

  11. Engineering haptic devices a beginner's guide

    CERN Document Server

    Hatzfeld, Christian

    2014-01-01

    In this greatly reworked second edition of Engineering Haptic Devices the psychophysic content has been thoroughly revised and updated. Chapters on haptic interaction, system structures and design methodology were rewritten from scratch to include further basic principles and recent findings. New chapters on the evaluation of haptic systems and the design of three exemplary haptic systems from science and industry have been added. This book was written for students and engineers that are faced with the development of a task-specific haptic system. It is a reference book for the basics of hap

  12. 1st International AsiaHaptics conference

    CERN Document Server

    Ando, Hideyuki; Kyung, Ki-Uk

    2015-01-01

    This book is aimed not only at haptics and human interface researchers, but also at developers and designers from manufacturing corporations and the entertainment industry who are working to change our lives. This publication comprises the proceedings of the first International AsiaHaptics conference, held in Tsukuba, Japan, in 2014. The book describes the state of the art of the diverse haptics- (touch-) related research, including scientific research into haptics perception and illusion, development of haptics devices, and applications for a wide variety of fields such as education, medicine, telecommunication, navigation, and entertainment.

  13. Perceiving haptic feedback in virtual reality simulators.

    Science.gov (United States)

    Våpenstad, Cecilie; Hofstad, Erlend Fagertun; Langø, Thomas; Mårvik, Ronald; Chmarra, Magdalena Karolina

    2013-07-01

    To improve patient safety, training of psychomotor laparoscopic skills is often done on virtual reality (VR) simulators outside the operating room. Haptic sensations have been found to influence psychomotor performance in laparoscopy. The emulation of haptic feedback is thus an important aspect of VR simulation. Some VR simulators try to simulate these sensations with handles equipped with haptic feedback. We conducted a survey on how laparoscopic surgeons perceive handles with and without haptic feedback. Surgeons with different levels of experience in laparoscopy were asked to test two handles: Xitact IHP with haptic feedback and Xitact ITP without haptic feedback (Mentice AB, Gothenburg, Sweden), connected to the LapSim (Surgical Science AB, Sweden) VR simulator. They performed two tasks on the simulator before answering 12 questions regarding the two handles. The surgeons were not informed about the differences in the handles. A total of 85 % of the 20 surgeons who participated in the survey claimed that it is important that handles with haptic feedback feel realistic. Ninety percent of the surgeons preferred the handles without haptic feedback. The friction in the handles with haptic feedback was perceived to be as in reality (5 %) or too high (95 %). Regarding the handles without haptic feedback, the friction was perceived as in reality (45 %), too low (50 %), or too high (5 %). A total of 85 % of the surgeons thought that the handle with haptic feedback attempts to simulate the resistance offered by tissue to deformation. Ten percent thought that the handle succeeds in doing so. The surveyed surgeons believe that haptic feedback is an important feature on VR simulators; however, they preferred the handles without haptic feedback because they perceived the handles with haptic feedback to add additional friction, making them unrealistic and not mechanically transparent.

  14. Surface meshing with curvature convergence

    KAUST Repository

    Li, Huibin; Zeng, Wei; Morvan, Jean-Marie; Chen, Liming; Gu, Xianfengdavid

    2014-01-01

    Surface meshing plays a fundamental role in graphics and visualization. Many geometric processing tasks involve solving geometric PDEs on meshes. The numerical stability, convergence rates and approximation errors are largely determined by the mesh qualities. In practice, Delaunay refinement algorithms offer satisfactory solutions to high quality mesh generations. The theoretical proofs for volume based and surface based Delaunay refinement algorithms have been established, but those for conformal parameterization based ones remain wide open. This work focuses on the curvature measure convergence for the conformal parameterization based Delaunay refinement algorithms. Given a metric surface, the proposed approach triangulates its conformal uniformization domain by the planar Delaunay refinement algorithms, and produces a high quality mesh. We give explicit estimates for the Hausdorff distance, the normal deviation, and the differences in curvature measures between the surface and the mesh. In contrast to the conventional results based on volumetric Delaunay refinement, our stronger estimates are independent of the mesh structure and directly guarantee the convergence of curvature measures. Meanwhile, our result on Gaussian curvature measure is intrinsic to the Riemannian metric and independent of the embedding. In practice, our meshing algorithm is much easier to implement and much more efficient. The experimental results verified our theoretical results and demonstrated the efficiency of the meshing algorithm. © 2014 IEEE.

  15. Surface meshing with curvature convergence

    KAUST Repository

    Li, Huibin

    2014-06-01

    Surface meshing plays a fundamental role in graphics and visualization. Many geometric processing tasks involve solving geometric PDEs on meshes. The numerical stability, convergence rates and approximation errors are largely determined by the mesh qualities. In practice, Delaunay refinement algorithms offer satisfactory solutions to high quality mesh generations. The theoretical proofs for volume based and surface based Delaunay refinement algorithms have been established, but those for conformal parameterization based ones remain wide open. This work focuses on the curvature measure convergence for the conformal parameterization based Delaunay refinement algorithms. Given a metric surface, the proposed approach triangulates its conformal uniformization domain by the planar Delaunay refinement algorithms, and produces a high quality mesh. We give explicit estimates for the Hausdorff distance, the normal deviation, and the differences in curvature measures between the surface and the mesh. In contrast to the conventional results based on volumetric Delaunay refinement, our stronger estimates are independent of the mesh structure and directly guarantee the convergence of curvature measures. Meanwhile, our result on Gaussian curvature measure is intrinsic to the Riemannian metric and independent of the embedding. In practice, our meshing algorithm is much easier to implement and much more efficient. The experimental results verified our theoretical results and demonstrated the efficiency of the meshing algorithm. © 2014 IEEE.

  16. Haptic and Audio Interaction Design

    DEFF Research Database (Denmark)

    This book constitutes the refereed proceedings of the 5th International Workshop on Haptic and Audio Interaction Design, HAID 2010 held in Copenhagen, Denmark, in September 2010. The 21 revised full papers presented were carefully reviewed and selected for inclusion in the book. The papers are or...

  17. Introduction to haptics for neurosurgeons.

    Science.gov (United States)

    L'Orsa, Rachael; Macnab, Chris J B; Tavakoli, Mahdi

    2013-01-01

    Robots are becoming increasingly relevant to neurosurgeons, extending a neurosurgeon's physical capabilities, improving navigation within the surgical landscape when combined with advanced imaging, and propelling the movement toward minimally invasive surgery. Most surgical robots, however, isolate surgeons from the full range of human senses during a procedure. This forces surgeons to rely on vision alone for guidance through the surgical corridor, which limits the capabilities of the system, requires significant operator training, and increases the surgeon's workload. Incorporating haptics into these systems, ie, enabling the surgeon to "feel" forces experienced by the tool tip of the robot, could render these limitations obsolete by making the robot feel more like an extension of the surgeon's own body. Although the use of haptics in neurosurgical robots is still mostly the domain of research, neurosurgeons who keep abreast of this emerging field will be more prepared to take advantage of it as it becomes more prevalent in operating theaters. Thus, this article serves as an introduction to the field of haptics for neurosurgeons. We not only outline the current and future benefits of haptics but also introduce concepts in the fields of robotic technology and computer control. This knowledge will allow readers to be better aware of limitations in the technology that can affect performance and surgical outcomes, and "knowing the right questions to ask" will be invaluable for surgeons who have purchasing power within their departments.

  18. Implementing quantum Ricci curvature

    Science.gov (United States)

    Klitgaard, N.; Loll, R.

    2018-05-01

    Quantum Ricci curvature has been introduced recently as a new, geometric observable characterizing the curvature properties of metric spaces, without the need for a smooth structure. Besides coordinate invariance, its key features are scalability, computability, and robustness. We demonstrate that these properties continue to hold in the context of nonperturbative quantum gravity, by evaluating the quantum Ricci curvature numerically in two-dimensional Euclidean quantum gravity, defined in terms of dynamical triangulations. Despite the well-known, highly nonclassical properties of the underlying quantum geometry, its Ricci curvature can be matched well to that of a five-dimensional round sphere.

  19. GDP growth and the yield curvature

    DEFF Research Database (Denmark)

    Møller, Stig Vinther

    2014-01-01

    This paper examines the forecastability of GDP growth using information from the term structure of yields. In contrast to previous studies, the paper shows that the curvature of the yield curve contributes with much more forecasting power than the slope of yield curve. The yield curvature also...... predicts bond returns, implying a common element to time-variation in expected bond returns and expected GDP growth....

  20. Virtual Reality and Haptics for Product Assembly

    Directory of Open Access Journals (Sweden)

    Maria Teresa Restivo

    2012-01-01

    Full Text Available Haptics can significantly enhance the user's sense of immersion and interactivity. An industrial application of virtual reality and haptics for product assembly is described in this paper, which provides a new and low-cost approach for product assembly design, assembly task planning and assembly operation training. A demonstration of the system with haptics device interaction was available at the session of exp.at'11.

  1. Introducing quantum Ricci curvature

    Science.gov (United States)

    Klitgaard, N.; Loll, R.

    2018-02-01

    Motivated by the search for geometric observables in nonperturbative quantum gravity, we define a notion of coarse-grained Ricci curvature. It is based on a particular way of extracting the local Ricci curvature of a smooth Riemannian manifold by comparing the distance between pairs of spheres with that of their centers. The quantum Ricci curvature is designed for use on non-smooth and discrete metric spaces, and to satisfy the key criteria of scalability and computability. We test the prescription on a variety of regular and random piecewise flat spaces, mostly in two dimensions. This enables us to quantify its behavior for short lattices distances and compare its large-scale behavior with that of constantly curved model spaces. On the triangulated spaces considered, the quantum Ricci curvature has good averaging properties and reproduces classical characteristics on scales large compared to the discretization scale.

  2. Pseudo-Haptic Feedback in Teleoperation.

    Science.gov (United States)

    Neupert, Carsten; Matich, Sebastian; Scherping, Nick; Kupnik, Mario; Werthschutzky, Roland; Hatzfeld, Christian

    2016-01-01

    In this paper, we develop possible realizations of pseudo-haptic feedback in teleoperation systems based on existing works for pseudo-haptic feedback in virtual reality and the intended applications. We derive four potential factors affecting the performance of haptic feedback (calculation operator, maximum displacement, offset force, and scaling factor), which are analyzed in three compliance identification experiments. First, we analyze the principle usability of pseudo-haptic feedback by comparing information transfer measures for teleoperation and direct interaction. Pseudo-haptic interaction yields well above-chance performance, while direct interaction performs almost perfectly. In order to optimize pseudo-haptic feedback, in the second study we perform a full-factorial experimental design with 36 subjects performing 6,480 trials with 36 different treatments. Information transfer ranges from 0.68 bit to 1.72 bit in a task with a theoretical maximum of 2.6 bit, with a predominant effect of the calculation operator and a minor effect of the maximum displacement. In a third study, short- and long-term learning effects are analyzed. Learning effects regarding the performance of pseudo-haptic feedback cannot be observed for single-day experiments. Tests over 10 days show a maximum increase in information transfer of 0.8 bit. The results show the feasibility of pseudo-haptic feedback for teleoperation and can be used as design basis for task-specific systems.

  3. Virtual reality haptic human dissection.

    Science.gov (United States)

    Needham, Caroline; Wilkinson, Caroline; Soames, Roger

    2011-01-01

    This project aims to create a three-dimensional digital model of the human hand and wrist which can be virtually 'dissected' through a haptic interface. Tissue properties will be added to the various anatomical structures to replicate a realistic look and feel. The project will explore the role of the medical artist and investigate the cross-discipline collaborations required in the field of virtual anatomy. The software will be used to train anatomy students in dissection skills before experience on a real cadaver. The effectiveness of the software will be evaluated and assessed both quantitatively as well as qualitatively.

  4. Review of Designs for Haptic Data Visualization.

    Science.gov (United States)

    Paneels, Sabrina; Roberts, Jonathan C

    2010-01-01

    There are many different uses for haptics, such as training medical practitioners, teleoperation, or navigation of virtual environments. This review focuses on haptic methods that display data. The hypothesis is that haptic devices can be used to present information, and consequently, the user gains quantitative, qualitative, or holistic knowledge about the presented data. Not only is this useful for users who are blind or partially sighted (who can feel line graphs, for instance), but also the haptic modality can be used alongside other modalities, to increase the amount of variables being presented, or to duplicate some variables to reinforce the presentation. Over the last 20 years, a significant amount of research has been done in haptic data presentation; e.g., researchers have developed force feedback line graphs, bar charts, and other forms of haptic representations. However, previous research is published in different conferences and journals, with different application emphases. This paper gathers and collates these various designs to provide a comprehensive review of designs for haptic data visualization. The designs are classified by their representation: Charts, Maps, Signs, Networks, Diagrams, Images, and Tables. This review provides a comprehensive reference for researchers and learners, and highlights areas for further research.

  5. Haptic feedback improves surgeons' user experience and fracture reduction in facial trauma simulation.

    Science.gov (United States)

    Girod, Sabine; Schvartzman, Sara C; Gaudilliere, Dyani; Salisbury, Kenneth; Silva, Rebeka

    2016-01-01

    Computer-assisted surgical (CAS) planning tools are available for craniofacial surgery, but are usually based on computer-aided design (CAD) tools that lack the ability to detect the collision of virtual objects (i.e., fractured bone segments). We developed a CAS system featuring a sense of touch (haptic) that enables surgeons to physically interact with individual, patient-specific anatomy and immerse in a three-dimensional virtual environment. In this study, we evaluated initial user experience with our novel system compared to an existing CAD system. Ten surgery resident trainees received a brief verbal introduction to both the haptic and CAD systems. Users simulated mandibular fracture reduction in three clinical cases within a 15 min time limit for each system and completed a questionnaire to assess their subjective experience. We compared standard landmarks and linear and angular measurements between the simulated results and the actual surgical outcome and found that haptic simulation results were not significantly different from actual postoperative outcomes. In contrast, CAD results significantly differed from both the haptic simulation and actual postoperative results. In addition to enabling a more accurate fracture repair, the haptic system provided a better user experience than the CAD system in terms of intuitiveness and self-reported quality of repair.

  6. Advanced Curvature Deformable Mirrors

    Science.gov (United States)

    2010-09-01

    ORGANIZATION NAME(S) AND ADDRESS(ES) University of Hawaii ,Institute for Astronomy,640 North A‘ohoku Place, #209 , Hilo ,HI,96720-2700 8. PERFORMING...Advanced Curvature Deformable Mirrors Christ Ftaclas1,2, Aglae Kellerer2 and Mark Chun2 Institute for Astronomy, University of Hawaii

  7. Development of haptic system for surgical robot

    Science.gov (United States)

    Gang, Han Gyeol; Park, Jiong Min; Choi, Seung-Bok; Sohn, Jung Woo

    2017-04-01

    In this paper, a new type of haptic system for surgical robot application is proposed and its performances are evaluated experimentally. The proposed haptic system consists of an effective master device and a precision slave robot. The master device has 3-DOF rotational motion as same as human wrist motion. It has lightweight structure with a gyro sensor and three small-sized MR brakes for position measurement and repulsive torque generation, respectively. The slave robot has 3-DOF rotational motion using servomotors, five bar linkage and a torque sensor is used to measure resistive torque. It has been experimentally demonstrated that the proposed haptic system has good performances on tracking control of desired position and repulsive torque. It can be concluded that the proposed haptic system can be effectively applied to the surgical robot system in real field.

  8. fMRI-Compatible Electromagnetic Haptic Interface.

    Science.gov (United States)

    Riener, R; Villgrattner, T; Kleiser, R; Nef, T; Kollias, S

    2005-01-01

    A new haptic interface device is suggested, which can be used for functional magnetic resonance imaging (fMRI) studies. The basic component of this 1 DOF haptic device are two coils that produce a Lorentz force induced by the large static magnetic field of the MR scanner. A MR-compatible optical angular encoder and a optical force sensor enable the implementation of different control architectures for haptic interactions. The challenge was to provide a large torque, and not to affect image quality by the currents applied in the device. The haptic device was tested in a 3T MR scanner. With a current of up to 1A and a distance of 1m to the focal point of the MR-scanner it was possible to generate torques of up to 4 Nm. Within these boundaries image quality was not affected.

  9. Haptic device for telerobotic surgery

    Science.gov (United States)

    Salisbury, Curt; Salisbury, Jr., J. Kenneth

    2014-12-30

    A haptic device for telerobotic surgery, including a base; a linkage system having first and second linkage members coupled to the base; a motor that provides a motor force; a transmission including first and second driving pulleys arranged such that their faces form an angle and their axes form a plane, first and second idler pulleys offset from the plane and arranged between the first and second driving pulleys such that their axes divide the angle between the first and second driving pulleys, and a cable that traverses the first and second driving pulleys and the set of idler pulleys and transfers the motor force to the linkage system; an end effector coupled to distal ends of the first and second linkage members and maneuverable relative to the base; and a controller that modulates the motor force to simulate a body part at a point portion of the end effector.

  10. The Haptic Bracelets: Learning Multi-Limb Rhythm Skills from Haptic Stimuli While Reading

    NARCIS (Netherlands)

    Bouwer, A.; Holland, S.; Dalgleish, M.; Holland, S.; Wilkie, K.; Mulholland, P.; Seago, A.

    2013-01-01

    The Haptic Bracelets are a system designed to help people learn multi-limbed rhythms (which involve multiple simultaneous rhythmic patterns) while they carry out other tasks. The Haptic Bracelets consist of vibrotactiles attached to each wrist and ankle, together with a computer system to control

  11. Regularized strings with extrinsic curvature

    International Nuclear Information System (INIS)

    Ambjoern, J.; Durhuus, B.

    1987-07-01

    We analyze models of discretized string theories, where the path integral over world sheet variables is regularized by summing over triangulated surfaces. The inclusion of curvature in the action is a necessity for the scaling of the string tension. We discuss the physical properties of models with extrinsic curvature terms in the action and show that the string tension vanishes at the critical point where the bare extrinsic curvature coupling tends to infinity. Similar results are derived for models with intrinsic curvature. (orig.)

  12. UPPER LIMB FUNCTIONAL ASSESSMENT USING HAPTIC INTERFACE

    Directory of Open Access Journals (Sweden)

    Aleš Bardorfer

    2004-12-01

    Full Text Available A new method for the assessment of the upper limb (UL functional state, using a haptic interface is presented. A haptic interface is used as a measuring device, capable of providing objective, repeatable and quantitative data of the UL motion. A patient is presented with a virtual environment, both graphically via a computer screen and haptically via the Phantom Premium 1.5 haptic interface. The setup allows the patient to explore and feel the virtual environment with three of his/her senses; sight, hearing, and most important, touch. Specially designed virtual environments are used to assess the patient’s UL movement capabilities. The tests range from tracking tasks – to assess the accuracy of movement – tracking tasks with added disturbances in a form of random forces – to assess the patient’s control abilities, a labyrinth test – to assess both speed and accuracy, to the last test for measuring the maximal force capacity of the UL.A new method for the assessment of the upper limb (UL functional state, using a haptic interface is presented. A haptic interface is used as a measuring device, capable of providing objective, repeatable and quantitative data of the UL motion. A patient is presented with a virtual environment, both graphically via a computer screen and haptically via the Phantom Premium 1.5 haptic interface. The setup allows the patient to explore and feel the virtual environment with three of his/her senses; sight, hearing, and most important, touch. Specially designed virtual environments are used to assess the patient’s UL movement capabilities. The tests range from tracking tasks–to assess the accuracy of movement-tracking tasks with added disturbances in a form of random forces-to assess the patient’s control abilities, a labyrinth test-to assess both speed and accuracy, to the last test for measuring the maximal force capacity of the UL.A comprehensive study, using the developed measurement setup within the

  13. Brane cosmology with curvature corrections

    International Nuclear Information System (INIS)

    Kofinas, Georgios; Maartens, Roy; Papantonopoulos, Eleftherios

    2003-01-01

    We study the cosmology of the Randall-Sundrum brane-world where the Einstein-Hilbert action is modified by curvature correction terms: a four-dimensional scalar curvature from induced gravity on the brane, and a five-dimensional Gauss-Bonnet curvature term. The combined effect of these curvature corrections to the action removes the infinite-density big bang singularity, although the curvature can still diverge for some parameter values. A radiation brane undergoes accelerated expansion near the minimal scale factor, for a range of parameters. This acceleration is driven by the geometric effects, without an inflation field or negative pressures. At late times, conventional cosmology is recovered. (author)

  14. Video Game Device Haptic Interface for Robotic Arc Welding

    Energy Technology Data Exchange (ETDEWEB)

    Corrie I. Nichol; Milos Manic

    2009-05-01

    Recent advances in technology for video games have made a broad array of haptic feedback devices available at low cost. This paper presents a bi-manual haptic system to enable an operator to weld remotely using the a commercially available haptic feedback video game device for the user interface. The system showed good performance in initial tests, demonstrating the utility of low cost input devices for remote haptic operations.

  15. Developing Visual Editors for High-Resolution Haptic Patterns

    DEFF Research Database (Denmark)

    Cuartielles, David; Göransson, Andreas; Olsson, Tony

    2012-01-01

    In this article we give an overview of our iterative work in developing visual editors for creating high resolution haptic patterns to be used in wearable, haptic feedback devices. During the past four years we have found the need to address the question of how to represent, construct and edit high...... resolution haptic patterns so that they translate naturally to the user’s haptic experience. To solve this question we have developed and tested several visual editors...

  16. Haptic and Audio-visual Stimuli: Enhancing Experiences and Interaction

    NARCIS (Netherlands)

    Nijholt, Antinus; Dijk, Esko O.; Lemmens, Paul M.C.; Luitjens, S.B.

    2010-01-01

    The intention of the symposium on Haptic and Audio-visual stimuli at the EuroHaptics 2010 conference is to deepen the understanding of the effect of combined Haptic and Audio-visual stimuli. The knowledge gained will be used to enhance experiences and interactions in daily life. To this end, a

  17. Incorporating Haptic Feedback in Simulation for Learning Physics

    Science.gov (United States)

    Han, Insook; Black, John B.

    2011-01-01

    The purpose of this study was to investigate the effectiveness of a haptic augmented simulation in learning physics. The results indicate that haptic augmented simulations, both the force and kinesthetic and the purely kinesthetic simulations, were more effective than the equivalent non-haptic simulation in providing perceptual experiences and…

  18. Precise Haptic Device Co-Location for Visuo-Haptic Augmented Reality.

    Science.gov (United States)

    Eck, Ulrich; Pankratz, Frieder; Sandor, Christian; Klinker, Gudrun; Laga, Hamid

    2015-12-01

    Visuo-haptic augmented reality systems enable users to see and touch digital information that is embedded in the real world. PHANToM haptic devices are often employed to provide haptic feedback. Precise co-location of computer-generated graphics and the haptic stylus is necessary to provide a realistic user experience. Previous work has focused on calibration procedures that compensate the non-linear position error caused by inaccuracies in the joint angle sensors. In this article we present a more complete procedure that additionally compensates for errors in the gimbal sensors and improves position calibration. The proposed procedure further includes software-based temporal alignment of sensor data and a method for the estimation of a reference for position calibration, resulting in increased robustness against haptic device initialization and external tracker noise. We designed our procedure to require minimal user input to maximize usability. We conducted an extensive evaluation with two different PHANToMs, two different optical trackers, and a mechanical tracker. Compared to state-of-the-art calibration procedures, our approach significantly improves the co-location of the haptic stylus. This results in higher fidelity visual and haptic augmentations, which are crucial for fine-motor tasks in areas such as medical training simulators, assembly planning tools, or rapid prototyping applications.

  19. Haptic Edge Detection Through Shear

    Science.gov (United States)

    Platkiewicz, Jonathan; Lipson, Hod; Hayward, Vincent

    2016-03-01

    Most tactile sensors are based on the assumption that touch depends on measuring pressure. However, the pressure distribution at the surface of a tactile sensor cannot be acquired directly and must be inferred from the deformation field induced by the touched object in the sensor medium. Currently, there is no consensus as to which components of strain are most informative for tactile sensing. Here, we propose that shape-related tactile information is more suitably recovered from shear strain than normal strain. Based on a contact mechanics analysis, we demonstrate that the elastic behavior of a haptic probe provides a robust edge detection mechanism when shear strain is sensed. We used a jamming-based robot gripper as a tactile sensor to empirically validate that shear strain processing gives accurate edge information that is invariant to changes in pressure, as predicted by the contact mechanics study. This result has implications for the design of effective tactile sensors as well as for the understanding of the early somatosensory processing in mammals.

  20. Haptic interfaces using dielectric electroactive polymers

    Science.gov (United States)

    Ozsecen, Muzaffer Y.; Sivak, Mark; Mavroidis, Constantinos

    2010-04-01

    Quality, amplitude and frequency of the interaction forces between a human and an actuator are essential traits for haptic applications. A variety of Electro-Active Polymer (EAP) based actuators can provide these characteristics simultaneously with quiet operation, low weight, high power density and fast response. This paper demonstrates a rolled Dielectric Elastomer Actuator (DEA) being used as a telepresence device in a heart beat measurement application. In the this testing, heart signals were acquired from a remote location using a wireless heart rate sensor, sent through a network and DEA was used to haptically reproduce the heart beats at the medical expert's location. A series of preliminary human subject tests were conducted that demonstrated that a) DE based haptic feeling can be used in heart beat measurement tests and b) through subjective testing the stiffness and actuator properties of the EAP can be tuned for a variety of applications.

  1. Haptic spatial matching in near peripersonal space.

    Science.gov (United States)

    Kaas, Amanda L; Mier, Hanneke I van

    2006-04-01

    Research has shown that haptic spatial matching at intermanual distances over 60 cm is prone to large systematic errors. The error pattern has been explained by the use of reference frames intermediate between egocentric and allocentric coding. This study investigated haptic performance in near peripersonal space, i.e. at intermanual distances of 60 cm and less. Twelve blindfolded participants (six males and six females) were presented with two turn bars at equal distances from the midsagittal plane, 30 or 60 cm apart. Different orientations (vertical/horizontal or oblique) of the left bar had to be matched by adjusting the right bar to either a mirror symmetric (/ \\) or parallel (/ /) position. The mirror symmetry task can in principle be performed accurately in both an egocentric and an allocentric reference frame, whereas the parallel task requires an allocentric representation. Results showed that parallel matching induced large systematic errors which increased with distance. Overall error was significantly smaller in the mirror task. The task difference also held for the vertical orientation at 60 cm distance, even though this orientation required the same response in both tasks, showing a marked effect of task instruction. In addition, men outperformed women on the parallel task. Finally, contrary to our expectations, systematic errors were found in the mirror task, predominantly at 30 cm distance. Based on these findings, we suggest that haptic performance in near peripersonal space might be dominated by different mechanisms than those which come into play at distances over 60 cm. Moreover, our results indicate that both inter-individual differences and task demands affect task performance in haptic spatial matching. Therefore, we conclude that the study of haptic spatial matching in near peripersonal space might reveal important additional constraints for the specification of adequate models of haptic spatial performance.

  2. The role of haptic versus visual volume cues in the size-weight illusion.

    Science.gov (United States)

    Ellis, R R; Lederman, S J

    1993-03-01

    Three experiments establish the size-weight illusion as a primarily haptic phenomenon, despite its having been more traditionally considered an example of vision influencing haptic processing. Experiment 1 documents, across a broad range of stimulus weights and volumes, the existence of a purely haptic size-weight illusion, equal in strength to the traditional illusion. Experiment 2 demonstrates that haptic volume cues are both sufficient and necessary for a full-strength illusion. In contrast, visual volume cues are merely sufficient, and produce a relatively weaker effect. Experiment 3 establishes that congenitally blind subjects experience an effect as powerful as that of blindfolded sighted observers, thus demonstrating that visual imagery is also unnecessary for a robust size-weight illusion. The results are discussed in terms of their implications for both sensory and cognitive theories of the size-weight illusion. Applications of this work to a human factors design and to sensor-based systems for robotic manipulation are also briefly considered.

  3. Improved haptic interface for colonoscopy simulation.

    Science.gov (United States)

    Woo, Hyun Soo; Kim, Woo Seok; Ahn, Woojin; Lee, Doo Yong; Yi, Sun Young

    2007-01-01

    This paper presents an improved haptic interface of the KAIST-Ewha colonoscopy simulator II. The haptic interface enables the distal portion of the colonoscope to be freely bent while guaranteeing enough workspace and reflective forces for colonoscopy simulation. Its force-torque sensor measures profiles of the user. Manipulation of the colonoscope tip is monitored by four deflection sensors, and triggers computation to render accurate graphic images corresponding to the angle knob rotation. Tack switches are attached on the valve-actuation buttons of the colonoscope to simulate air-injection or suction, and the corresponding deformation of the colon.

  4. Haptic rendering for simulation of fine manipulation

    CERN Document Server

    Wang, Dangxiao; Zhang, Yuru

    2014-01-01

    This book introduces the latest progress in six degrees of freedom (6-DoF) haptic rendering with the focus on a new approach for simulating force/torque feedback in performing tasks that require dexterous manipulation skills. One of the major challenges in 6-DoF haptic rendering is to resolve the conflict between high speed and high fidelity requirements, especially in simulating a tool interacting with both rigid and deformable objects in a narrow space and with fine features. The book presents a configuration-based optimization approach to tackle this challenge. Addressing a key issue in man

  5. On Gauss-Bonnet Curvatures

    Directory of Open Access Journals (Sweden)

    Mohammed Larbi Labbi

    2007-12-01

    Full Text Available The $(2k$-th Gauss-Bonnet curvature is a generalization to higher dimensions of the $(2k$-dimensional Gauss-Bonnet integrand, it coincides with the usual scalar curvature for $k = 1$. The Gauss-Bonnet curvatures are used in theoretical physics to describe gravity in higher dimensional space times where they are known as the Lagrangian of Lovelock gravity, Gauss-Bonnet Gravity and Lanczos gravity. In this paper we present various aspects of these curvature invariants and review their variational properties. In particular, we discuss natural generalizations of the Yamabe problem, Einstein metrics and minimal submanifolds.

  6. Inflation in a shear-or curvature-dominated universe

    International Nuclear Information System (INIS)

    Steigman, G.; Turner, M.S.

    1983-01-01

    We show that new inflation occurs even if the universe is shear-or (negative) curvature-dominated when the phase transition begins. In such situations the size of a causally coherent region, after inflation, is only slightly smaller (by powers, but not by exponential factors) than the usual result. The creation and evolution of density perturbations is unaffected. This result is marked contrast to 'old' inflation, where shear- or curvature-domination could quench inflation. (orig.)

  7. Curvature effects in carbon nanomaterials: Exohedral versus endohedral supercapacitors

    OpenAIRE

    Huang, Jingsong; Bobby,; Sumpter, Bobby G.; Meunier, Vincent; Yushin, Gleb; Portet, Cristelle; Gogotsi, Yury

    2010-01-01

    Capacitive energy storage mechanisms in nanoporous carbon supercapacitors hinge on endohedral interactions in carbon materials with macro-, meso-, and micropores that have negative surface curvature. In this article, we show that because of the positive curvature found in zero-dimensional carbon onions or one-dimensional carbon nanotube arrays, exohedral interactions cause the normalized capacitance to increase with decreasing particle size or tube diameter, in sharp contrast to the behavior ...

  8. Feeling form: the neural basis of haptic shape perception.

    Science.gov (United States)

    Yau, Jeffrey M; Kim, Sung Soo; Thakur, Pramodsingh H; Bensmaia, Sliman J

    2016-02-01

    The tactile perception of the shape of objects critically guides our ability to interact with them. In this review, we describe how shape information is processed as it ascends the somatosensory neuraxis of primates. At the somatosensory periphery, spatial form is represented in the spatial patterns of activation evoked across populations of mechanoreceptive afferents. In the cerebral cortex, neurons respond selectively to particular spatial features, like orientation and curvature. While feature selectivity of neurons in the earlier processing stages can be understood in terms of linear receptive field models, higher order somatosensory neurons exhibit nonlinear response properties that result in tuning for more complex geometrical features. In fact, tactile shape processing bears remarkable analogies to its visual counterpart and the two may rely on shared neural circuitry. Furthermore, one of the unique aspects of primate somatosensation is that it contains a deformable sensory sheet. Because the relative positions of cutaneous mechanoreceptors depend on the conformation of the hand, the haptic perception of three-dimensional objects requires the integration of cutaneous and proprioceptive signals, an integration that is observed throughout somatosensory cortex. Copyright © 2016 the American Physiological Society.

  9. Effects of 3D virtual haptics force feedback on brand personality perception: the mediating role of physical presence in advergames.

    Science.gov (United States)

    Jin, Seung-A Annie

    2010-06-01

    This study gauged the effects of force feedback in the Novint Falcon haptics system on the sensory and cognitive dimensions of a virtual test-driving experience. First, in order to explore the effects of tactile stimuli with force feedback on users' sensory experience, feelings of physical presence (the extent to which virtual physical objects are experienced as actual physical objects) were measured after participants used the haptics interface. Second, to evaluate the effects of force feedback on the cognitive dimension of consumers' virtual experience, this study investigated brand personality perception. The experiment utilized the Novint Falcon haptics controller to induce immersive virtual test-driving through tactile stimuli. The author designed a two-group (haptics stimuli with force feedback versus no force feedback) comparison experiment (N = 238) by manipulating the level of force feedback. Users in the force feedback condition were exposed to tactile stimuli involving various force feedback effects (e.g., terrain effects, acceleration, and lateral forces) while test-driving a rally car. In contrast, users in the control condition test-drove the rally car using the Novint Falcon but were not given any force feedback. Results of ANOVAs indicated that (a) users exposed to force feedback felt stronger physical presence than those in the no force feedback condition, and (b) users exposed to haptics stimuli with force feedback perceived the brand personality of the car to be more rugged than those in the control condition. Managerial implications of the study for product trial in the business world are discussed.

  10. P1-17: Pseudo-Haptics Using Motion-in-Depth Stimulus and Second-Order Motion Stimulus

    Directory of Open Access Journals (Sweden)

    Shuichi Sato

    2012-10-01

    Full Text Available Modification of motion of the computer cursor during the manipulation by the observer evokes illusory haptic sensation (Lecuyer et al., 2004 ACM SIGCHI '04 239–246. This study investigates the pseudo-haptics using motion-in-depth and second-order motion. A stereoscopic display and a PHANTOM were used in the first experiment. A subject was asked to move a visual target at a constant speed in horizontal, vertical, or front-back direction. During the manipulation, the speed was reduced to 50% for 500 msec. The haptic sensation was measured using the magnitude estimation method. The result indicates that perceived haptic sensation from motion-in-depth was about 30% of that from horizontal or vertical motion. A 2D display and the PHANTOM were used in the second experiment. The motion cue was second order—in each frame, dots in a square patch reverses in contrast (i.e., all black dots become white and all white dots become black. The patch was moved in a horizontal direction. The result indicates that perceived haptic sensation from second-order motion was about 90% of that from first-order motion.

  11. Haptic interventions as visual anthropology’

    DEFF Research Database (Denmark)

    Kirstein Høgel, Arine

    2017-01-01

    This vignette arose in the course of a practice-led research project using “haptic interventions” to investigate contemporary consumption of cultural pasts and cultural difference. The vignette presents reworkings of unused and newly digitised archival material shot in the Persian Gulf in the 1950s...

  12. Multimodal Sensing Interface for Haptic Interaction

    Directory of Open Access Journals (Sweden)

    Carlos Diaz

    2017-01-01

    Full Text Available This paper investigates the integration of a multimodal sensing system for exploring limits of vibrato tactile haptic feedback when interacting with 3D representation of real objects. In this study, the spatial locations of the objects are mapped to the work volume of the user using a Kinect sensor. The position of the user’s hand is obtained using the marker-based visual processing. The depth information is used to build a vibrotactile map on a haptic glove enhanced with vibration motors. The users can perceive the location and dimension of remote objects by moving their hand inside a scanning region. A marker detection camera provides the location and orientation of the user’s hand (glove to map the corresponding tactile message. A preliminary study was conducted to explore how different users can perceive such haptic experiences. Factors such as total number of objects detected, object separation resolution, and dimension-based and shape-based discrimination were evaluated. The preliminary results showed that the localization and counting of objects can be attained with a high degree of success. The users were able to classify groups of objects of different dimensions based on the perceived haptic feedback.

  13. Representations of space based on haptic input

    NARCIS (Netherlands)

    Zuidhoek, S.

    2005-01-01

    The present thesis focused on the representations of grasping space based on haptic input. We aimed at identifying their characteristics, and the underlying neurocognitive processes and mechanisms. To this end, we studied the systematic distortions in performance on several orientation perception

  14. Testing haptic sensations for spinal anesthesia.

    LENUS (Irish Health Repository)

    2011-01-01

    Having identified key determinants of teaching and learning spinal anesthesia, it was necessary to characterize and render the haptic sensations (feeling of touch) associated with needle insertion in the lower back. The approach used is to match recreated sensations (eg, "pop" through skin or dura mater) with experts\\' perceptions of the equivalent clinical events.

  15. Manifolds of positive scalar curvature

    Energy Technology Data Exchange (ETDEWEB)

    Stolz, S [Department of Mathematics, University of Notre Dame, Notre Dame (United States)

    2002-08-15

    This lecture gives an survey on the problem of finding a positive scalar curvature metric on a closed manifold. The Gromov-Lawson-Rosenberg conjecture and its relation to the Baum-Connes conjecture are discussed and the problem of finding a positive Ricci curvature metric on a closed manifold is explained.

  16. Some Inequalities for the -Curvature Image

    Directory of Open Access Journals (Sweden)

    Daijun Wei

    2009-01-01

    Full Text Available Lutwak introduced the notion of -curvature image and proved an inequality for the volumes of convex body and its -curvature image. In this paper, we first give an monotonic property of -curvature image. Further, we establish two inequalities for the -curvature image and its polar, respectively. Finally, an inequality for the volumes of -projection body and -curvature image is obtained.

  17. Lectures on mean curvature flows

    CERN Document Server

    Zhu, Xi-Ping

    2002-01-01

    "Mean curvature flow" is a term that is used to describe the evolution of a hypersurface whose normal velocity is given by the mean curvature. In the simplest case of a convex closed curve on the plane, the properties of the mean curvature flow are described by Gage-Hamilton's theorem. This theorem states that under the mean curvature flow, the curve collapses to a point, and if the flow is diluted so that the enclosed area equals \\pi, the curve tends to the unit circle. In this book, the author gives a comprehensive account of fundamental results on singularities and the asymptotic behavior of mean curvature flows in higher dimensions. Among other topics, he considers in detail Huisken's theorem (a generalization of Gage-Hamilton's theorem to higher dimension), evolution of non-convex curves and hypersurfaces, and the classification of singularities of the mean curvature flow. Because of the importance of the mean curvature flow and its numerous applications in differential geometry and partial differential ...

  18. Bilateral intraocular lens subluxation secondary to haptic angulation.

    Science.gov (United States)

    Moreno-Montañés, Javier; Fernández-Hortelano, Ana; Caire, Josemaría

    2008-04-01

    An 82-year-old man had uneventful phacoemulsification with bilateral implantation of a hydrophilic acrylic, single-piece intraocular lens (IOL) (ACR6D SE, Laboratoires Cornéal). Five years later, simultaneous and bilateral IOL subluxations occurred. In both eyes, the subluxation was situated on the side of one haptic that had moved forward (temporal area in the right eye and superior area in the left eye). In the right eye, the haptic-capsular bag was entrapped by the pupil and produced endothelial damage. A transscleral suture was placed over and under the subluxated haptic through the anterior and posterior capsules to capture the haptic. The haptic was then sutured to the sclera. No postoperative complications developed. We hypothesize that 10-degree angulated and broad haptic junctions can lead to zonular damage and IOL subluxation.

  19. Environmental influences on DNA curvature

    DEFF Research Database (Denmark)

    Ussery, David; Higgins, C.F.; Bolshoy, A.

    1999-01-01

    DNA curvature plays an important role in many biological processes. To study environmentalinfluences on DNA curvature we compared the anomalous migration on polyacrylamide gels ofligation ladders of 11 specifically-designed oligonucleotides. At low temperatures (25 degreesC and below) most......, whilst spermine enhanced theanomalous migration of a different set of sequences. Sequences with a GGC motif exhibitedgreater curvature than predicted by the presently-used angles for the nearest-neighbour wedgemodel and are especially sensitive to Mg2+. The data have implications for models...... for DNAcurvature and for environmentally-sensitive DNA conformations in the regulation of geneexpression....

  20. Curvature force and dark energy

    International Nuclear Information System (INIS)

    Balakin, Alexander B; Pavon, Diego; Schwarz, Dominik J; Zimdahl, Winfried

    2003-01-01

    A curvature self-interaction of the cosmic gas is shown to mimic a cosmological constant or other forms of dark energy, such as a rolling tachyon condensate or a Chaplygin gas. Any given Hubble rate and deceleration parameter can be traced back to the action of an effective curvature force on the gas particles. This force self-consistently reacts back on the cosmological dynamics. The links between an imperfect fluid description, a kinetic description with effective antifriction forces and curvature forces, which represent a non-minimal coupling of gravity to matter, are established

  1. Haptic sense and the politicization of contemporary image

    Directory of Open Access Journals (Sweden)

    Tarcisio Torres Silva

    2017-08-01

    Full Text Available In this paper, it is intended to propose a theoretical approach to the political effects of the sense of touch/haptic in order to understand to what extent the intensification of contemporary haptic experience contributes to create proximity and engagement among individuals overloaded by too much visual information offered by multiple media. At the end, it is mentioned the work of Brazilian artist Rodrigo Braga to exemplify the contemporary political use of haptic sense.

  2. Haptic Feedback for the GPU-based Surgical Simulator

    DEFF Research Database (Denmark)

    Sørensen, Thomas Sangild; Mosegaard, Jesper

    2006-01-01

    The GPU has proven to be a powerful processor to compute spring-mass based surgical simulations. It has not previously been shown however, how to effectively implement haptic interaction with a simulation running entirely on the GPU. This paper describes a method to calculate haptic feedback...... with limited performance cost. It allows easy balancing of the GPU workload between calculations of simulation, visualisation, and the haptic feedback....

  3. Codimension two branes and distributional curvature

    International Nuclear Information System (INIS)

    Traschen, Jennie

    2009-01-01

    In general relativity, there is a well-developed formalism for working with the approximation that a gravitational source is concentrated on a shell, or codimension one surface. In contrast, there are obstacles to concentrating sources on surfaces that have a higher codimension, for example, a string in a spacetime with a dimension greater than or equal to four. Here it is shown that, by giving up some of the generality of the codimension one case, curvature can be concentrated on submanifolds that have codimension two. A class of metrics is identified such that (1) the scalar curvature and Ricci densities exist as distributions with support on a codimension two submanifold, and (2) using the Einstein equation, the distributional curvature corresponds to a concentrated stress-energy with equation of state p = -ρ, where p is the isotropic pressure tangent to the submanifold, and ρ is the energy density. This is the appropriate stress-energy to describe a self-gravitating brane that is governed by an area action, or a braneworld deSitter cosmology. The possibility of having a different equation of state arise from a wider class of metrics is discussed.

  4. Simulation and training of lumbar punctures using haptic volume rendering and a 6DOF haptic device

    Science.gov (United States)

    Färber, Matthias; Heller, Julika; Handels, Heinz

    2007-03-01

    The lumbar puncture is performed by inserting a needle into the spinal chord of the patient to inject medicaments or to extract liquor. The training of this procedure is usually done on the patient guided by experienced supervisors. A virtual reality lumbar puncture simulator has been developed in order to minimize the training costs and the patient's risk. We use a haptic device with six degrees of freedom (6DOF) to feedback forces that resist needle insertion and rotation. An improved haptic volume rendering approach is used to calculate the forces. This approach makes use of label data of relevant structures like skin, bone, muscles or fat and original CT data that contributes information about image structures that can not be segmented. A real-time 3D visualization with optional stereo view shows the punctured region. 2D visualizations of orthogonal slices enable a detailed impression of the anatomical context. The input data consisting of CT and label data and surface models of relevant structures is defined in an XML file together with haptic rendering and visualization parameters. In a first evaluation the visible human male data has been used to generate a virtual training body. Several users with different medical experience tested the lumbar puncture trainer. The simulator gives a good haptic and visual impression of the needle insertion and the haptic volume rendering technique enables the feeling of unsegmented structures. Especially, the restriction of transversal needle movement together with rotation constraints enabled by the 6DOF device facilitate a realistic puncture simulation.

  5. Development of a Virtual Guitar using Haptic Device

    OpenAIRE

    田村,真晴; 山下,英生

    2009-01-01

    In recent years, a haptic device that output power as one of the computer output devices has been developed. We can get the feeling that we really touch the material through a sensor of haptic device when we touch a material simulated in a computer. In this research, a virtual guitar in which the feeling playing guitar and the sound volume are changed by adjusting power to input with a haptic device was developed. With the haptic device we feel as if we play a genuine guitar. Moreover, it see...

  6. A Semi-automated Approach to Improve the Efficiency of Medical Imaging Segmentation for Haptic Rendering.

    Science.gov (United States)

    Banerjee, Pat; Hu, Mengqi; Kannan, Rahul; Krishnaswamy, Srinivasan

    2017-08-01

    The Sensimmer platform represents our ongoing research on simultaneous haptics and graphics rendering of 3D models. For simulation of medical and surgical procedures using Sensimmer, 3D models must be obtained from medical imaging data, such as magnetic resonance imaging (MRI) or computed tomography (CT). Image segmentation techniques are used to determine the anatomies of interest from the images. 3D models are obtained from segmentation and their triangle reduction is required for graphics and haptics rendering. This paper focuses on creating 3D models by automating the segmentation of CT images based on the pixel contrast for integrating the interface between Sensimmer and medical imaging devices, using the volumetric approach, Hough transform method, and manual centering method. Hence, automating the process has reduced the segmentation time by 56.35% while maintaining the same accuracy of the output at ±2 voxels.

  7. Neodymium:YAG laser cutting of intraocular lens haptics in vitro and in vivo.

    Science.gov (United States)

    Feder, J M; Rosenberg, M A; Farber, M D

    1989-09-01

    Various complications following intraocular lens (IOL) surgery result in explantation of the lenses. Haptic fibrosis may necessitate cutting the IOL haptics prior to removal. In this study we used the neodymium: YAG (Nd:YAG) laser to cut polypropylene and poly(methyl methacrylate) (PMMA) haptics in vitro and in rabbit eyes. In vitro we were able to cut 100% of both haptic types successfully (28 PMMA and 30 polypropylene haptics). In rabbit eyes we were able to cut 50% of the PMMA haptics and 43% of the polypropylene haptics. Poly(methyl methacrylate) haptics were easier to cut in vitro and in vivo than polypropylene haptics, requiring fewer shots for transection. Complications of Nd:YAG laser use frequently interfered with haptic transections in rabbit eyes. Haptic transection may be more easily accomplished in human eyes.

  8. Development of a wearable haptic game interface

    Directory of Open Access Journals (Sweden)

    J. Foottit

    2016-04-01

    Full Text Available This paper outlines the ongoing development of a wearable haptic game interface, in this case for controlling a flight simulator. The device differs from many traditional haptic feedback implementations in that it combines vibrotactile feedback with gesture based input, thus becoming a two-way conduit between the user and the virtual environment. The device is intended to challenge what is considered an “interface” and sets out to purposefully blur the boundary between man and machine. This allows for a more immersive experience, and a user evaluation shows that the intuitive interface allows the user to become the aircraft that is controlled by the movements of the user's hand.

  9. A haptic floor for interaction and diagnostics with goal based tasks during virtual reality supported balance training

    Directory of Open Access Journals (Sweden)

    Andrej Krpič

    2014-03-01

    Full Text Available Background: Balance training of patients after stroke is one of the primary tasks of physiotherapy after the hospitalization. It is based on the intensive training, which consists of simple, repetitive, goal-based tasks. The tasks are carried out by physiotherapists, who follow predefined protocols. Introduction of a standing frame and a virtual reality decrease the physical load and number of required physiotherapists. The patients benefit in terms of safety and increased motivation. Additional feedback – haptic floor can enhance the virtual reality experience, add additional level of difficulty and could be also used for generating postural perturbations. The purpose of this article is to examine whether haptic information can be used to identify specific anomalies in dynamic posturography.Methods: The performance and stability of closed-loop system of the haptic floor were tested using frequency analysis. A postural response normative was set up from data assessed in four healthy individuals who were exposed to unexpected movements of the haptic floor in eight directions. Postural responses of a patient after stroke participating in virtual reality supported balance training, where collisions resulted in floor movements, were assessed and contrasted to the normative.Results: Haptic floor system was stable and controllable up to the frequency of 1.1 Hz, sufficient for the generation of postural perturbations. Responses obtained after perturbations in two major directions for a patient after stroke demonstrated noticeable deviations from the normative.Conclusions: Haptic floor design, together with a standing frame and a virtual reality used for balance training, enables an assessment of directionally specific postural responses. The system was designed to identify postural disorders during balance training and rehabilitation progress outside specialized clinics, e.g. at patient’s home.

  10. Haptic Control with a Robotic Gripper

    OpenAIRE

    Rody, Morgan

    2011-01-01

    The Novint Falcon is a low cost, 3-axis, haptic device primarily designed and built for the gaming industry. Meant to replace the conventional mouse, the Novint Falcon has sub- millimeter accuracy and is capable of real time updates. The device itself has the potential to be used in telerobotics applications when coupled with a robotic gripper for example. Recently, the Intelligent Control Lab at Örebro University in Sweden built such a robotic gripper. The robotic gripper has three fingers a...

  11. Haptic identification of objects and their depictions.

    Science.gov (United States)

    Klatzky, R L; Loomis, J M; Lederman, S J; Wake, H; Fujita, N

    1993-08-01

    Haptic identification of real objects is superior to that of raised two-dimensional (2-D) depictions. Three explanations of real-object superiority were investigated: contribution of material information, contribution of 3-D shape and size, and greater potential for integration across the fingers. In Experiment 1, subjects, while wearing gloves that gently attenuated material information, haptically identified real objects that provided reduced cues to compliance, mass, and part motion. The gloves permitted exploration with free hand movement, a single outstretched finger, or five outstretched fingers. Performance decreased over these three conditions but was superior to identification of pictures of the same objects in all cases, indicating the contribution of 3-D structure and integration across the fingers. Picture performance was also better with five fingers than with one. In Experiment 2, the subjects wore open-fingered gloves, which provided them with material information. Consequently, the effect of type of exploration was substantially reduced but not eliminated. Material compensates somewhat for limited access to object structure but is not the primary basis for haptic object identification.

  12. Discrete Curvature Theories and Applications

    KAUST Repository

    Sun, Xiang

    2016-08-25

    Discrete Di erential Geometry (DDG) concerns discrete counterparts of notions and methods in di erential geometry. This thesis deals with a core subject in DDG, discrete curvature theories on various types of polyhedral surfaces that are practically important for free-form architecture, sunlight-redirecting shading systems, and face recognition. Modeled as polyhedral surfaces, the shapes of free-form structures may have to satisfy di erent geometric or physical constraints. We study a combination of geometry and physics { the discrete surfaces that can stand on their own, as well as having proper shapes for the manufacture. These proper shapes, known as circular and conical meshes, are closely related to discrete principal curvatures. We study curvature theories that make such surfaces possible. Shading systems of freeform building skins are new types of energy-saving structures that can re-direct the sunlight. From these systems, discrete line congruences across polyhedral surfaces can be abstracted. We develop a new curvature theory for polyhedral surfaces equipped with normal congruences { a particular type of congruences de ned by linear interpolation of vertex normals. The main results are a discussion of various de nitions of normality, a detailed study of the geometry of such congruences, and a concept of curvatures and shape operators associated with the faces of a triangle mesh. These curvatures are compatible with both normal congruences and the Steiner formula. In addition to architecture, we consider the role of discrete curvatures in face recognition. We use geometric measure theory to introduce the notion of asymptotic cones associated with a singular subspace of a Riemannian manifold, which is an extension of the classical notion of asymptotic directions. We get a simple expression of these cones for polyhedral surfaces, as well as convergence and approximation theorems. We use the asymptotic cones as facial descriptors and demonstrate the

  13. Human detection and discrimination of tactile repeatability, mechanical backlash, and temporal delay in a combined tactile-kinesthetic haptic display system.

    Science.gov (United States)

    Doxon, Andrew J; Johnson, David E; Tan, Hong Z; Provancher, William R

    2013-01-01

    Many of the devices used in haptics research are over-engineered for the task and are designed with capabilities that go far beyond human perception levels. Designing devices that more closely match the limits of human perception will make them smaller, less expensive, and more useful. However, many device-centric perception thresholds have yet to be evaluated. To this end, three experiments were conducted, using one degree-of-freedom contact location feedback device in combination with a kinesthetic display, to provide a more explicit set of specifications for similar tactile-kinesthetic haptic devices. The first of these experiments evaluated the ability of humans to repeatedly localize tactile cues across the fingerpad. Subjects could localize cues to within 1.3 mm and showed bias toward the center of the fingerpad. The second experiment evaluated the minimum perceptible difference of backlash at the tactile element. Subjects were able to discriminate device backlash in excess of 0.46 mm on low-curvature models and 0.93 mm on high-curvature models. The last experiment evaluated the minimum perceptible difference of system delay between user action and device reaction. Subjects were able to discriminate delays in excess of 61 ms. The results from these studies can serve as the maximum (i.e., most demanding) device specifications for most tactile-kinesthetic haptic systems.

  14. Preliminary Experiment Combining Virtual Reality Haptic Shoes and Audio Synthesis

    DEFF Research Database (Denmark)

    Nordahl, Rolf; Berrezag, Amir; Dimitrov, Smilen

    2010-01-01

    We describe a system that provides combined auditory and haptic sensations to simulate walking on different grounds. It uses a physical model that drives haptic transducers embedded in sandals and headphones. The model represents walking interactions with solid surfaces that can creak, or be cove...

  15. Teaching Classical Mechanics Concepts Using Visuo-Haptic Simulators

    Science.gov (United States)

    Neri, Luis; Noguez, Julieta; Robledo-Rella, Victor; Escobar-Castillejos, David; Gonzalez-Nucamendi, Andres

    2018-01-01

    In this work, the design and implementation of several physics scenarios using haptic devices are presented and discussed. Four visuo-haptic applications were developed for an undergraduate engineering physics course. Experiments with experimental and control groups were designed and implemented. Activities and exercises related to classical…

  16. Haptic and Visual feedback in 3D Audio Mixing Interfaces

    DEFF Research Database (Denmark)

    Gelineck, Steven; Overholt, Daniel

    2015-01-01

    This paper describes the implementation and informal evaluation of a user interface that explores haptic feedback for 3D audio mixing. The implementation compares different approaches using either the LEAP Motion for mid-air hand gesture control, or the Novint Falcon for active haptic feed- back...

  17. Structural impact detection with vibro-haptic interfaces

    Science.gov (United States)

    Jung, Hwee-Kwon; Park, Gyuhae; Todd, Michael D.

    2016-07-01

    This paper presents a new sensing paradigm for structural impact detection using vibro-haptic interfaces. The goal of this study is to allow humans to ‘feel’ structural responses (impact, shape changes, and damage) and eventually determine health conditions of a structure. The target applications for this study are aerospace structures, in particular, airplane wings. Both hardware and software components are developed to realize the vibro-haptic-based impact detection system. First, L-shape piezoelectric sensor arrays are deployed to measure the acoustic emission data generated by impacts on a wing. Unique haptic signals are then generated by processing the measured acoustic emission data. These haptic signals are wirelessly transmitted to human arms, and with vibro-haptic interface, human pilots could identify impact location, intensity and possibility of subsequent damage initiation. With the haptic interface, the experimental results demonstrate that human could correctly identify such events, while reducing false indications on structural conditions by capitalizing on human’s classification capability. Several important aspects of this study, including development of haptic interfaces, design of optimal human training strategies, and extension of the haptic capability into structural impact detection are summarized in this paper.

  18. A magnetorheological haptic cue accelerator for manual transmission vehicles

    International Nuclear Information System (INIS)

    Han, Young-Min; Noh, Kyung-Wook; Choi, Seung-Bok; Lee, Yang-Sub

    2010-01-01

    This paper proposes a new haptic cue function for manual transmission vehicles to achieve optimal gear shifting. This function is implemented on the accelerator pedal by utilizing a magnetorheological (MR) brake mechanism. By combining the haptic cue function with the accelerator pedal, the proposed haptic cue device can transmit the optimal moment of gear shifting for manual transmission to a driver without requiring the driver's visual attention. As a first step to achieve this goal, a MR fluid-based haptic device is devised to enable rotary motion of the accelerator pedal. Taking into account spatial limitations, the design parameters are optimally determined using finite element analysis to maximize the relative control torque. The proposed haptic cue device is then manufactured and its field-dependent torque and time response are experimentally evaluated. Then the manufactured MR haptic cue device is integrated with the accelerator pedal. A simple virtual vehicle emulating the operation of the engine of a passenger vehicle is constructed and put into communication with the haptic cue device. A feed-forward torque control algorithm for the haptic cue is formulated and control performances are experimentally evaluated and presented in the time domain

  19. Haptic Glove Technology: Skill Development through Video Game Play

    Science.gov (United States)

    Bargerhuff, Mary Ellen; Cowan, Heidi; Oliveira, Francisco; Quek, Francis; Fang, Bing

    2010-01-01

    This article introduces a recently developed haptic glove system and describes how the participants used a video game that was purposely designed to train them in skills that are needed for the efficient use of the haptic glove. Assessed skills included speed, efficiency, embodied skill, and engagement. The findings and implications for future…

  20. Haptic Routes and digestive destinations in cooking series

    DEFF Research Database (Denmark)

    Waade, Anne Marit; Jørgensen, Ulla Angkjær

    2010-01-01

    and the media in which aesthetical, cultural and symbolic values are related to the way food is mediatised. The main argument is that cooking television series produce haptic images of place and food that include a specific sensuous and emotional relation between screen and viewer. The haptic imagery...

  1. Semantic congruence in audio-haptic simulation of footsteps

    DEFF Research Database (Denmark)

    Turchet, Luca; Serafin, Stefania

    2014-01-01

    of semantic congruence for those audio–haptic pairs of materials which belonged to the same typology. Furthermore, better matching ability was found for the passive case compared to the interactive one, although this may be due to the limits of the technology used for the interactive haptic simulations....

  2. Haptic feedback designs in teleoperation systems for minimal invasive surgery

    NARCIS (Netherlands)

    Font, I.; Weiland, S.; Franken, M.; Steinbuch, M.; Rovers, A.F.

    2004-01-01

    One of the major shortcomings of state-of-the-art robotic systems for minimal invasive surgery is the lack of haptic feedback for the surgeon. In order to provide haptic information, sensors and actuators have to be added to the master and slave device. A control system should process the data and

  3. Evaluation of flexible endoscope steering using haptic guidance

    NARCIS (Netherlands)

    Reilink, Rob; Stramigioli, Stefano; Kappers, Astrid M L; Misra, Sarthak

    Background: Steering the tip of a flexible endoscope relies on the physician's dexterity and experience. For complex flexible endoscopes, conventional controls may be inadequate. Methods: A steering method based on a multi-degree-of-freedom haptic device is presented. Haptic cues are generated based

  4. Evaluation of flexible endoscope steering using haptic guidance

    NARCIS (Netherlands)

    Reilink, Rob; Stramigioli, Stefano; Kappers, Astrid M.L.; Misra, Sarthak

    2011-01-01

    Background - Steering the tip of a flexible endoscope relies on the physician’s dexterity and experience. For complex flexible endoscopes, conventional controls may be inadequate. Methods - A steering method based on a multi-degree-of-freedom haptic device is presented. Haptic cues are generated

  5. Prevailing Trends in Haptic Feedback Simulation for Minimally Invasive Surgery.

    Science.gov (United States)

    Pinzon, David; Byrns, Simon; Zheng, Bin

    2016-08-01

    Background The amount of direct hand-tool-tissue interaction and feedback in minimally invasive surgery varies from being attenuated in laparoscopy to being completely absent in robotic minimally invasive surgery. The role of haptic feedback during surgical skill acquisition and its emphasis in training have been a constant source of controversy. This review discusses the major developments in haptic simulation as they relate to surgical performance and the current research questions that remain unanswered. Search Strategy An in-depth review of the literature was performed using PubMed. Results A total of 198 abstracts were returned based on our search criteria. Three major areas of research were identified, including advancements in 1 of the 4 components of haptic systems, evaluating the effectiveness of haptic integration in simulators, and improvements to haptic feedback in robotic surgery. Conclusions Force feedback is the best method for tissue identification in minimally invasive surgery and haptic feedback provides the greatest benefit to surgical novices in the early stages of their training. New technology has improved our ability to capture, playback and enhance to utility of haptic cues in simulated surgery. Future research should focus on deciphering how haptic training in surgical education can increase performance, safety, and improve training efficiency. © The Author(s) 2016.

  6. Curvature bound from gravitational catalysis

    Science.gov (United States)

    Gies, Holger; Martini, Riccardo

    2018-04-01

    We determine bounds on the curvature of local patches of spacetime from the requirement of intact long-range chiral symmetry. The bounds arise from a scale-dependent analysis of gravitational catalysis and its influence on the effective potential for the chiral order parameter, as induced by fermionic fluctuations on a curved spacetime with local hyperbolic properties. The bound is expressed in terms of the local curvature scalar measured in units of a gauge-invariant coarse-graining scale. We argue that any effective field theory of quantum gravity obeying this curvature bound is safe from chiral symmetry breaking through gravitational catalysis and thus compatible with the simultaneous existence of chiral fermions in the low-energy spectrum. With increasing number of dimensions, the curvature bound in terms of the hyperbolic scale parameter becomes stronger. Applying the curvature bound to the asymptotic safety scenario for quantum gravity in four spacetime dimensions translates into bounds on the matter content of particle physics models.

  7. Effect on High versus Low Fidelity Haptic Feedback in a Virtual Reality Baseball Simulation

    DEFF Research Database (Denmark)

    Ryge, Andreas Nicolaj; Thomsen, Lui Albæk; Berthelsen, Theis

    2017-01-01

    In this paper we present a within-subjects study (n=26) comparing participants' experience of three kinds of haptic feedback (no haptic feedback, low fidelity haptic feedback and high fidelity haptic feedback) simulating the impact between a virtual baseball bat and ball. We noticed some minor ef...

  8. Enhancing audiovisual experience with haptic feedback: a survey on HAV.

    Science.gov (United States)

    Danieau, F; Lecuyer, A; Guillotel, P; Fleureau, J; Mollet, N; Christie, M

    2013-01-01

    Haptic technology has been widely employed in applications ranging from teleoperation and medical simulation to art and design, including entertainment, flight simulation, and virtual reality. Today there is a growing interest among researchers in integrating haptic feedback into audiovisual systems. A new medium emerges from this effort: haptic-audiovisual (HAV) content. This paper presents the techniques, formalisms, and key results pertinent to this medium. We first review the three main stages of the HAV workflow: the production, distribution, and rendering of haptic effects. We then highlight the pressing necessity for evaluation techniques in this context and discuss the key challenges in the field. By building on existing technologies and tackling the specific challenges of the enhancement of audiovisual experience with haptics, we believe the field presents exciting research perspectives whose financial and societal stakes are significant.

  9. Design of high-fidelity haptic display for one-dimensional force reflection applications

    Science.gov (United States)

    Gillespie, Brent; Rosenberg, Louis B.

    1995-12-01

    This paper discusses the development of a virtual reality platform for the simulation of medical procedures which involve needle insertion into human tissue. The paper's focus is the hardware and software requirements for haptic display of a particular medical procedure known as epidural analgesia. To perform this delicate manual procedure, an anesthesiologist must carefully guide a needle through various layers of tissue using only haptic cues for guidance. As a simplifying aspect for the simulator design, all motions and forces involved in the task occur along a fixed line once insertion begins. To create a haptic representation of this procedure, we have explored both physical modeling and perceptual modeling techniques. A preliminary physical model was built based on CT-scan data of the operative site. A preliminary perceptual model was built based on current training techniques for the procedure provided by a skilled instructor. We compare and contrast these two modeling methods and discuss the implications of each. We select and defend the perceptual model as a superior approach for the epidural analgesia simulator.

  10. FGB: A Graphical and Haptic User Interface for Creating Graphical, Haptic User Interfaces

    International Nuclear Information System (INIS)

    ANDERSON, THOMAS G.; BRECKENRIDGE, ARTHURINE; DAVIDSON, GEORGE S.

    1999-01-01

    The emerging field of haptics represents a fundamental change in human-computer interaction (HCI), and presents solutions to problems that are difficult or impossible to solve with a two-dimensional, mouse-based interface. To take advantage of the potential of haptics, however, innovative interaction techniques and programming environments are needed. This paper describes FGB (FLIGHT GHUI Builder), a programming tool that can be used to create an application specific graphical and haptic user interface (GHUI). FGB is itself a graphical and haptic user interface with which a programmer can intuitively create and manipulate components of a GHUI in real time in a graphical environment through the use of a haptic device. The programmer can create a GHUI without writing any programming code. After a user interface is created, FGB writes the appropriate programming code to a file, using the FLIGHT API, to recreate what the programmer created in the FGB interface. FGB saves programming time and increases productivity, because a programmer can see the end result as it is created, and FGB does much of the programming itself. Interestingly, as FGB was created, it was used to help build itself. The further FGB was in its development, the more easily and quickly it could be used to create additional functionality and improve its own design. As a finished product, FGB can be used to recreate itself in much less time than it originally required, and with much less programming. This paper describes FGB's GHUI components, the techniques used in the interface, how the output code is created, where programming additions and modifications should be placed, and how it can be compared to and integrated with existing API's such as MFC and Visual C++, OpenGL, and GHOST

  11. Wide-Area Haptic Guidance: Taking the User by the Hand

    OpenAIRE

    Pérez Arias, Antonia; Hanebeck, Uwe D.

    2010-01-01

    In this paper, we present a novel use of haptic information in extended range telepresence, the wide-area haptic guidance. It consists of force and position signals applied to the user's hand in order to improve safety, accuracy, and speed in some telepresent tasks. Wide-area haptic guidance assists the user in reaching a desired position in a remote environment of arbitrary size without degrading the feeling of presence. Several methods for haptic guidance are analyzed. With active haptic gu...

  12. Enhancing Mediated Interpersonal Communication through Affective Haptics

    Science.gov (United States)

    Tsetserukou, Dzmitry; Neviarouskaya, Alena; Prendinger, Helmut; Kawakami, Naoki; Ishizuka, Mitsuru; Tachi, Susumu

    Driven by the motivation to enhance emotionally immersive experience of real-time messaging in 3D virtual world Second Life, we are proposing a conceptually novel approach to reinforcing (intensifying) own feelings and reproducing (simulating) the emotions felt by the partner through specially designed system, iFeel_IM!. In the paper we are describing the development of novel haptic devices (HaptiHeart, HaptiHug, HaptiTickler, HaptiCooler, and HaptiWarmer) integrated into iFeel_IM! system, which architecture is presented in detail.

  13. Haptic rendering foundations, algorithms, and applications

    CERN Document Server

    Lin, Ming C

    2008-01-01

    For a long time, human beings have dreamed of a virtual world where it is possible to interact with synthetic entities as if they were real. It has been shown that the ability to touch virtual objects increases the sense of presence in virtual environments. This book provides an authoritative overview of state-of-theart haptic rendering algorithms and their applications. The authors examine various approaches and techniques for designing touch-enabled interfaces for a number of applications, including medical training, model design, and maintainability analysis for virtual prototyping, scienti

  14. Haptic seat for fuel economy feedback

    Energy Technology Data Exchange (ETDEWEB)

    Bobbitt, III, John Thomas

    2016-08-30

    A process of providing driver fuel economy feedback is disclosed in which vehicle sensors provide for haptic feedback on fuel usage. Such sensors may include one or more of a speed sensors, global position satellite units, vehicle pitch/roll angle sensors, suspension displacement sensors, longitudinal accelerometer sensors, throttle position in sensors, steering angle sensors, break pressure sensors, and lateral accelerometer sensors. Sensors used singlely or collectively can provide enhanced feedback as to various environmental conditions and operating conditions such that a more accurate assessment of fuel economy information can be provided to the driver.

  15. A prescribing geodesic curvature problem

    International Nuclear Information System (INIS)

    Chang, K.C.; Liu, J.Q.

    1993-09-01

    Let D be the unit disk and k be a function on S 1 = δD. Find a flat metric which is pointwise conformal to the standard metric and has k as the geodesic curvature of S 1 . A sufficient condition for the existence of such a metric is that the harmonic extension of k in D has saddle points. (author). 11 refs

  16. Mechatronic design of haptic forceps for robotic surgery.

    Science.gov (United States)

    Rizun, P; Gunn, D; Cox, B; Sutherland, G

    2006-12-01

    Haptic feedback increases operator performance and comfort during telerobotic manipulation. Feedback of grasping pressure is critical in many microsurgical tasks, yet no haptic interface for surgical tools is commercially available. Literature on the psychophysics of touch was reviewed to define the spectrum of human touch perception and the fidelity requirements of an ideal haptic interface. Mechanical design and control literature was reviewed to translate the psychophysical requirements to engineering specification. High-fidelity haptic forceps were then developed through an iterative process between engineering and surgery. The forceps are a modular device that integrate with a haptic hand controller to add force feedback for tool actuation in telerobotic or virtual surgery. Their overall length is 153 mm and their mass is 125 g. A contact-free voice coil actuator generates force feedback at frequencies up to 800 Hz. Maximum force output is 6 N (2N continuous) and the force resolution is 4 mN. The forceps employ a contact-free magnetic position sensor as well as micro-machined accelerometers to measure opening/closing acceleration. Position resolution is 0.6 microm with 1.3 microm RMS noise. The forceps can simulate stiffness greater than 20N/mm or impedances smaller than 15 g with no noticeable haptic artifacts or friction. As telerobotic surgery evolves, haptics will play an increasingly important role. Copyright 2006 John Wiley & Sons, Ltd.

  17. Haptic perception accuracy depending on self-produced movement.

    Science.gov (United States)

    Park, Chulwook; Kim, Seonjin

    2014-01-01

    This study measured whether self-produced movement influences haptic perception ability (experiment 1) as well as the factors associated with levels of influence (experiment 2) in racket sports. For experiment 1, the haptic perception accuracy levels of five male table tennis experts and five male novices were examined under two different conditions (no movement vs. movement). For experiment 2, the haptic afferent subsystems of five male table tennis experts and five male novices were investigated in only the self-produced movement-coupled condition. Inferential statistics (ANOVA, t-test) and custom-made devices (shock & vibration sensor, Qualisys Track Manager) of the data were used to determine the haptic perception accuracy (experiment 1, experiment 2) and its association with expertise. The results of this research show that expert-level players acquire higher accuracy with less variability (racket vibration and angle) than novice-level players, especially in their self-produced movement coupled performances. The important finding from this result is that, in terms of accuracy, the skill-associated differences were enlarged during self-produced movement. To explain the origin of this difference between experts and novices, the functional variability of haptic afferent subsystems can serve as a reference. These two factors (self-produced accuracy and the variability of haptic features) as investigated in this study would be useful criteria for educators in racket sports and suggest a broader hypothesis for further research into the effects of the haptic accuracy related to variability.

  18. Audio-haptic interaction in simulated walking experiences

    DEFF Research Database (Denmark)

    Serafin, Stefania

    2011-01-01

    and interchangeable use of the haptic and auditory modality in floor interfaces, and for the synergy of perception and action in capturing and guiding human walking. We describe the technology developed in the context of this project, together with some experiments performed to evaluate the role of auditory......In this paper an overview of the work conducted on audio-haptic physically based simulation and evaluation of walking is provided. This work has been performed in the context of the Natural Interactive Walking (NIW) project, whose goal is to investigate possibilities for the integrated...... and haptic feedback in walking tasks....

  19. Expanding the Scope of Instant Messaging with Bidirectional Haptic Communication

    OpenAIRE

    Kim, Youngjae; Hahn, Minsoo

    2010-01-01

    This work was conducted on the combination of two fields, i.e., haptic and social messaging. Haptic is one of the most attention-drawing fields and the biggest buzzwords among nextgeneration users. Haptic is being applied to conventional devices such as the cellular phone and even the door lock. Diverse forms of media such as blogs, social network services, and instant messengers are used to send and receive messages. That is mainly why we focus on the messaging experience, the most frequent ...

  20. Cosmic curvature tested directly from observations

    Science.gov (United States)

    Denissenya, Mikhail; Linder, Eric V.; Shafieloo, Arman

    2018-03-01

    Cosmic spatial curvature is a fundamental geometric quantity of the Universe. We investigate a model independent, geometric approach to measure spatial curvature directly from observations, without any derivatives of data. This employs strong lensing time delays and supernova distance measurements to measure the curvature itself, rather than just testing consistency with flatness. We define two curvature estimators, with differing error propagation characteristics, that can crosscheck each other, and also show how they can be used to map the curvature in redshift slices, to test constancy of curvature as required by the Robertson-Walker metric. Simulating realizations of redshift distributions and distance measurements of lenses and sources, we estimate uncertainties on the curvature enabled by next generation measurements. The results indicate that the model independent methods, using only geometry without assuming forms for the energy density constituents, can determine the curvature at the ~6×10‑3 level.

  1. Curvature Entropy for Curved Profile Generation

    OpenAIRE

    Ujiie, Yoshiki; Kato, Takeo; Sato, Koichiro; Matsuoka, Yoshiyuki

    2012-01-01

    In a curved surface design, the overall shape features that emerge from combinations of shape elements are important. However, controlling the features of the overall shape in curved profiles is difficult using conventional microscopic shape information such as dimension. Herein two types of macroscopic shape information, curvature entropy and quadrature curvature entropy, quantitatively represent the features of the overall shape. The curvature entropy is calculated by the curvature distribu...

  2. A remark about the mean curvature

    International Nuclear Information System (INIS)

    Zhang Weitao.

    1992-11-01

    In this paper, we give an integral identity about the mean curvature in Sobolev space H 0 1 (Ω) intersection H 2 (Ω). Suppose the mean curvature on Γ=δΩ is positive, we prove some inequalities of the positive mean curvature and propose some open problems. (author). 4 refs

  3. The dark side of curvature

    International Nuclear Information System (INIS)

    Barenboim, Gabriela; Martínez, Enrique Fernández; Mena, Olga; Verde, Licia

    2010-01-01

    Geometrical tests such as the combination of the Hubble parameter H(z) and the angular diameter distance d A (z) can, in principle, break the degeneracy between the dark energy equation of state parameter w(z), and the spatial curvature Ω k in a direct, model-independent way. In practice, constraints on these quantities achievable from realistic experiments, such as those to be provided by Baryon Acoustic Oscillation (BAO) galaxy surveys in combination with CMB data, can resolve the cosmic confusion between the dark energy equation of state parameter and curvature only statistically and within a parameterized model for w(z). Combining measurements of both H(z) and d A (z) up to sufficiently high redshifts z ∼ 2 and employing a parameterization of the redshift evolution of the dark energy equation of state are the keys to resolve the w(z)−Ω k degeneracy

  4. Modern approaches to discrete curvature

    CERN Document Server

    Romon, Pascal

    2017-01-01

     This book provides a valuable glimpse into discrete curvature, a rich new field of research which blends discrete mathematics, differential geometry, probability and computer graphics. It includes a vast collection of ideas and tools which will offer something new to all interested readers. Discrete geometry has arisen as much as a theoretical development as in response to unforeseen challenges coming from applications. Discrete and continuous geometries have turned out to be intimately connected. Discrete curvature is the key concept connecting them through many bridges in numerous fields: metric spaces, Riemannian and Euclidean geometries, geometric measure theory, topology, partial differential equations, calculus of variations, gradient flows, asymptotic analysis, probability, harmonic analysis, graph theory, etc. In spite of its crucial importance both in theoretical mathematics and in applications, up to now, almost no books have provided a coherent outlook on this emerging field.

  5. Haptic interface of the KAIST-Ewha colonoscopy simulator II.

    Science.gov (United States)

    Woo, Hyun Soo; Kim, Woo Seok; Ahn, Woojin; Lee, Doo Yong; Yi, Sun Young

    2008-11-01

    This paper presents an improved haptic interface for the Korea Advanced Institute of Science and Technology Ewha Colonoscopy Simulator II. The haptic interface enables the distal portion of the colonoscope to be freely bent while guaranteeing sufficient workspace and reflective forces for colonoscopy simulation. Its force-torque sensor measures the profiles of the user. Manipulation of the colonoscope tip is monitored by four deflection sensors and triggers computations to render accurate graphic images corresponding to the rotation of the angle knob. Tack sensors are attached to the valve-actuation buttons of the colonoscope to simulate air injection or suction as well as the corresponding deformation of the colon. A survey study for face validation was conducted, and the result shows that the developed haptic interface provides realistic haptic feedback for colonoscopy simulations.

  6. Enhanced operator perception through 3D vision and haptic feedback

    Science.gov (United States)

    Edmondson, Richard; Light, Kenneth; Bodenhamer, Andrew; Bosscher, Paul; Wilkinson, Loren

    2012-06-01

    Polaris Sensor Technologies (PST) has developed a stereo vision upgrade kit for TALON® robot systems comprised of a replacement gripper camera and a replacement mast zoom camera on the robot, and a replacement display in the Operator Control Unit (OCU). Harris Corporation has developed a haptic manipulation upgrade for TALON® robot systems comprised of a replacement arm and gripper and an OCU that provides haptic (force) feedback. PST and Harris have recently collaborated to integrate the 3D vision system with the haptic manipulation system. In multiple studies done at Fort Leonard Wood, Missouri it has been shown that 3D vision and haptics provide more intuitive perception of complicated scenery and improved robot arm control, allowing for improved mission performance and the potential for reduced time on target. This paper discusses the potential benefits of these enhancements to robotic systems used for the domestic homeland security mission.

  7. A study on haptic collaborative game in shared virtual environment

    Science.gov (United States)

    Lu, Keke; Liu, Guanyang; Liu, Lingzhi

    2013-03-01

    A study on collaborative game in shared virtual environment with haptic feedback over computer networks is introduced in this paper. A collaborative task was used where the players located at remote sites and played the game together. The player can feel visual and haptic feedback in virtual environment compared to traditional networked multiplayer games. The experiment was desired in two conditions: visual feedback only and visual-haptic feedback. The goal of the experiment is to assess the impact of force feedback on collaborative task performance. Results indicate that haptic feedback is beneficial for performance enhancement for collaborative game in shared virtual environment. The outcomes of this research can have a powerful impact on the networked computer games.

  8. The contributions of vision and haptics to reaching and grasping

    Directory of Open Access Journals (Sweden)

    Kayla Dawn Stone

    2015-09-01

    Full Text Available This review aims to provide a comprehensive outlook on the sensory (visual and haptic contributions to reaching and grasping. The focus is on studies in developing children, normal and neuropsychological populations, and in sensory-deprived individuals. Studies have suggested a right-hand/left-hemisphere specialization for visually-guided grasping and a left-hand/right-hemisphere specialization for haptically-guided object recognition. This poses the interesting possibility that when vision is not available and grasping relies heavily on the haptic system, there is an advantage to use the left hand. We review the evidence for this possibility and dissect the unique contributions of the visual and haptic systems to grasping. We ultimately discuss how the integration of these two sensory modalities shape hand preference.

  9. [Haptic tracking control for minimally invasive robotic surgery].

    Science.gov (United States)

    Xu, Zhaohong; Song, Chengli; Wu, Wenwu

    2012-06-01

    Haptic feedback plays a significant role in minimally invasive robotic surgery (MIRS). A major deficiency of the current MIRS is the lack of haptic perception for the surgeon, including the commercially available robot da Vinci surgical system. In this paper, a dynamics model of a haptic robot is established based on Newton-Euler method. Because it took some period of time in exact dynamics solution, we used a digital PID arithmetic dependent on robot dynamics to ensure real-time bilateral control, and it could improve tracking precision and real-time control efficiency. To prove the proposed method, an experimental system in which two Novint Falcon haptic devices acting as master-slave system has been developed. Simulations and experiments showed proposed methods could give instrument force feedbacks to operator, and bilateral control strategy is an effective method to master-slave MIRS. The proposed methods could be used to tele-robotic system.

  10. Haptic Feedback for Enhancing Realism of Walking Simulations

    DEFF Research Database (Denmark)

    Turchet, Luca; Burelli, Paolo; Serafin, Stefania

    2013-01-01

    system. While during the use of the interactive system subjects physically walked, during the use of the non-interactive system the locomotion was simulated while subjects were sitting on a chair. In both the configurations subjects were exposed to auditory and audio-visual stimuli presented...... with and without the haptic feedback. Results of the experiments provide a clear preference towards the simulations enhanced with haptic feedback showing that the haptic channel can lead to more realistic experiences in both interactive and non-interactive configurations. The majority of subjects clearly...... appreciated the added feedback. However, some subjects found the added feedback disturbing and annoying. This might be due on one hand to the limits of the haptic simulation and on the other hand to the different individual desire to be involved in the simulations. Our findings can be applied to the context...

  11. A Taxonomy and Comparison of Haptic Actions for Disassembly Tasks

    National Research Council Canada - National Science Library

    Bloomfield, Aaron; Deng, Yu; Wampler, Jeff; Rondot, Pascale; Harth, Dina; McManus, Mary; Badler, Norman

    2003-01-01

    .... We conducted a series of human subject experiments to compare user performance and preference on a disassembly task with and without haptic feedback using CyberGlove, Phantom, and SpaceMouse interfaces...

  12. Faster simulated laparoscopic cholecystectomy with haptic feedback technology

    Directory of Open Access Journals (Sweden)

    Yiasemidou M

    2011-10-01

    Full Text Available Marina Yiasemidou, Daniel Glassman, Peter Vasas, Sarit Badiani, Bijendra Patel Barts and the London School of Medicine and Dentistry, Department of Upper GI Surgery, Barts and The Royal London Hospital, London, UK Background: Virtual reality simulators have been gradually introduced into surgical training. One of the enhanced features of the latest virtual simulators is haptic feedback. The usefulness of haptic feedback technology has been a matter of controversy in recent years. Previous studies have assessed the importance of haptic feedback in executing parts of a procedure or basic tasks, such as tissue grasping. The aim of this study was to assess the role of haptic feedback within a structured educational environment, based on the performance of junior surgical trainees after undergoing substantial simulation training. Methods: Novices, whose performance was assessed after several repetitions of a task, were recruited for this study. The performance of senior house officers at the last stage of a validated laparoscopic cholecystectomy curriculum was assessed. Nine senior house officers completed a validated laparoscopic cholecystectomy curriculum on a haptic simulator and nine on a nonhaptic simulator. Performance in terms of mean total time, mean total number of movements, and mean total path length at the last level of the validated curriculum (full procedure of laparoscopic cholecystectomy was compared between the two groups. Results: Haptic feedback significantly reduced the time required to complete the full procedure of laparoscopic cholecystectomy (mean total time for nonhaptic machine 608.83 seconds, mean total time for haptic machine 553.27 seconds; P = 0.019 while maintaining safety standards similar to those of the nonhaptic machine (mean total number of movements: nonhaptic machine 583.74, haptic machine 603.93, P = 0.145, mean total path length: for nonhaptic machine 1207.37 cm, for haptic machine 1262.36 cm, P = 0

  13. Sensorimotor Interactions in the Haptic Perception of Virtual Objects

    Science.gov (United States)

    1997-01-01

    the human user. 2 Compared to our understanding of vision and audition , our knowledge of the human haptic perception is very limited. Many basic...modalities such as vision and audition on haptic perception of viscosity or mass, for example. 116 Some preliminary work has already been done in this...string[3]; *posx="x" *forf="f’ *velv="v" * acca ="a" trial[64]; resp[64]; /* random number */ /* trial number */ /* index */ /* array holding stim

  14. Binding in haptics: integration of "what" and "where" information in working memory for active touch.

    Directory of Open Access Journals (Sweden)

    Franco Delogu

    Full Text Available Information about the identity and the location of perceptual objects can be automatically integrated in perception and working memory (WM. Contrasting results in visual and auditory WM studies indicate that the characteristics of feature-to-location binding can vary according to the sensory modality of the input. The present study provides first evidence of binding between "what" and "where" information in WM for haptic stimuli. In an old-new recognition task, blindfolded participants were presented in their peripersonal space with sequences of three haptic stimuli varying in texture and location. They were then required to judge if a single probe stimulus was previously included in the sequence. Recall was measured both in a condition in which both texture and location were relevant for the task (Experiment 1 and in two conditions where only one feature had to be recalled (Experiment 2. Results showed that when both features were task-relevant, even if the association of location and texture was neither necessary nor required to perform the task, participants exhibited a recall advantage in conditions in which the location and the texture of the target probe was kept unaltered between encoding and recall. By contrast, when only one feature was task-relevant, the concurrent feature did not influence the recall of the target feature. We conclude that attention to feature binding is not necessary for the emergence of feature integration in haptic WM. For binding to take place, however, it is necessary to encode and maintain in memory both the identity and the location of items.

  15. Design and Control of a Haptic Enabled Robotic Manipulator

    Directory of Open Access Journals (Sweden)

    Muhammad Yaqoob

    2015-07-01

    Full Text Available Robotic surgery offers various advantages over conventional surgery that includes less bleeding, less trauma, and more precise tissue cutting. However, even surgeons who use the best commercially available surgical robotic systems complain about the absence of haptic feedback in such systems. In this paper, we present the findings of our project to overcome this shortcoming of surgical robotic systems, in which a haptic-enabled robotic system based on master and slave topology is designed and developed. To detect real-time intrusion at the slave end, haptic feedback is implemented along with a programmable system on chip, functioning as an embedded system for processing information. In order to obtain real-time haptic feedback, force and motion sensors are mounted on each joint of the master and slave units. At the master end, results are displayed through a graphical user interface, along with the physical feeling of intrusion at the slave part. Apart from the obvious applications of the current system in robotic surgery, it could also be used in designing more intuitive video games with further precise haptic feedback mechanisms. Moreover, the results presented in our work should pave the way for further scientific investigation, to provide even better haptic mechanisms.

  16. Integration of Haptics in Agricultural Robotics

    Science.gov (United States)

    Kannan Megalingam, Rajesh; Sreekanth, M. M.; Sivanantham, Vinu; Sai Kumar, K.; Ghanta, Sriharsha; Surya Teja, P.; Reddy, Rajesh G.

    2017-08-01

    Robots can differentiate with open loop system and closed loop system robots. We face many problems when we do not have a feedback from robots. In this research paper, we are discussing all possibilities to achieve complete closed loop system for Multiple-DOF Robotic Arm, which is used in a coconut tree climbing and cutting robot by introducing a Haptic device. We are working on various sensors like tactile, vibration, force and proximity sensors for getting feedback. For monitoring the robotic arm achieved by graphical user interference software which simulates the working of the robotic arm, send the feedback of all the real time analog values which are produced by various sensors and provide real-time graphs for estimate the efficiency of the Robot.

  17. Robust haptic large distance telemanipulation for ITER

    International Nuclear Information System (INIS)

    Heck, D.J.F.; Heemskerk, C.J.M.; Koning, J.F.; Abbasi, A.; Nijmeijer, H.

    2013-01-01

    Highlights: • ITER remote handling maintenance can be controlled safely over a large distance. • Bilateral teleoperation experiments were performed in a local network. • Wave variables make the controller robust against constant communication delays. • Master and slave position synchronization guaranteed by proportional action. -- Abstract: During shutdowns, maintenance crews are expected to work in 24/6 shifts to perform critical remote handling maintenance tasks on the ITER system. In this article, we investigate the possibility to safely perform these haptic maintenance tasks remotely from control stations located anywhere around the world. To guarantee stability in time delayed bilateral teleoperation, the symmetric position tracking controller using wave variables is selected. This algorithm guarantees robustness against communication delays, can eliminate wave reflections and provide position synchronization of the master and slave devices. Experiments have been conducted under realistic local network bandwidth, latency and jitter constraints. They show sufficient transparency even for substantial communication delays

  18. Robust haptic large distance telemanipulation for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Heck, D.J.F., E-mail: d.j.f.heck@tue.nl [Eindhoven University of Technology, Department of Mechanical Engineering, Eindhoven (Netherlands); Heemskerk, C.J.M.; Koning, J.F. [Heemskerk Innovative Technologies, Sassenheim (Netherlands); Abbasi, A.; Nijmeijer, H. [Eindhoven University of Technology, Department of Mechanical Engineering, Eindhoven (Netherlands)

    2013-10-15

    Highlights: • ITER remote handling maintenance can be controlled safely over a large distance. • Bilateral teleoperation experiments were performed in a local network. • Wave variables make the controller robust against constant communication delays. • Master and slave position synchronization guaranteed by proportional action. -- Abstract: During shutdowns, maintenance crews are expected to work in 24/6 shifts to perform critical remote handling maintenance tasks on the ITER system. In this article, we investigate the possibility to safely perform these haptic maintenance tasks remotely from control stations located anywhere around the world. To guarantee stability in time delayed bilateral teleoperation, the symmetric position tracking controller using wave variables is selected. This algorithm guarantees robustness against communication delays, can eliminate wave reflections and provide position synchronization of the master and slave devices. Experiments have been conducted under realistic local network bandwidth, latency and jitter constraints. They show sufficient transparency even for substantial communication delays.

  19. Curvature Entropy for Curved Profile Generation

    Directory of Open Access Journals (Sweden)

    Koichiro Sato

    2012-03-01

    Full Text Available In a curved surface design, the overall shape features that emerge from combinations of shape elements are important. However, controlling the features of the overall shape in curved profiles is difficult using conventional microscopic shape information such as dimension. Herein two types of macroscopic shape information, curvature entropy and quadrature curvature entropy, quantitatively represent the features of the overall shape. The curvature entropy is calculated by the curvature distribution, and represents the complexity of a shape (one of the overall shape features. The quadrature curvature entropy is an improvement of the curvature entropy by introducing a Markov process to evaluate the continuity of a curvature and to approximate human cognition of the shape. Additionally, a shape generation method using a genetic algorithm as a calculator and the entropy as a shape generation index is presented. Finally, the applicability of the proposed method is demonstrated using the side view of an automobile as a design example.

  20. Dynamic Double Curvature Mould System

    DEFF Research Database (Denmark)

    Jepsen, Christian Raun; Kristensen, Mathias Kræmmergaard; Kirkegaard, Poul Henning

    2011-01-01

    The present paper describes a concept for a reconfigurable mould surface which is designed to fit the needs of contemporary architecture. The core of the concept presented is a dynamic surface manipulated into a given shape using a digital signal created directly from the CAD drawing of the design....... This happens fast, automatic and without production of waste, and the manipulated surface is fair and robust, eliminating the need for additional, manual treatment. Limitations to the possibilities of the flexible form are limited curvature and limited level of detail, making it especially suited for larger...

  1. A Study on Immersion and Presence of a Portable Hand Haptic System for Immersive Virtual Reality

    OpenAIRE

    Kim, Mingyu; Jeon, Changyu; Kim, Jinmo

    2017-01-01

    This paper proposes a portable hand haptic system using Leap Motion as a haptic interface that can be used in various virtual reality (VR) applications. The proposed hand haptic system was designed as an Arduino-based sensor architecture to enable a variety of tactile senses at low cost, and is also equipped with a portable wristband. As a haptic system designed for tactile feedback, the proposed system first identifies the left and right hands and then sends tactile senses (vibration and hea...

  2. Curvature-Controlled Topological Defects

    Directory of Open Access Journals (Sweden)

    Luka Mesarec

    2017-05-01

    Full Text Available Effectively, two-dimensional (2D closed films exhibiting in-plane orientational ordering (ordered shells might be instrumental for the realization of scaled crystals. In them, ordered shells are expected to play the role of atoms. Furthermore, topological defects (TDs within them would determine their valence. Namely, bonding among shells within an isotropic liquid matrix could be established via appropriate nano-binders (i.e., linkers which tend to be attached to the cores of TDs exploiting the defect core replacement mechanism. Consequently, by varying configurations of TDs one could nucleate growth of scaled crystals displaying different symmetries. For this purpose, it is of interest to develop a simple and robust mechanism via which one could control the position and number of TDs in such atoms. In this paper, we use a minimal mesoscopic model, where variational parameters are the 2D curvature tensor and the 2D orientational tensor order parameter. We demonstrate numerically the efficiency of the effective topological defect cancellation mechanism to predict positional assembling of TDs in ordered films characterized by spatially nonhomogeneous Gaussian curvature. Furthermore, we show how one could efficiently switch among qualitatively different structures by using a relative volume v of ordered shells, which represents a relatively simple naturally accessible control parameter.

  3. Haptic Paddle Enhancements and a Formal Assessment of Student Learning in System Dynamics

    Science.gov (United States)

    Gorlewicz, Jenna L.; Kratchman, Louis B.; Webster, Robert J., III

    2014-01-01

    The haptic paddle is a force-feedback joystick used at several universities in teaching System Dynamics, a core mechanical engineering undergraduate course where students learn to model dynamic systems in several domains. A second goal of the haptic paddle is to increase the accessibility of robotics and haptics by providing a low-cost device for…

  4. Visual-Haptic Integration: Cue Weights are Varied Appropriately, to Account for Changes in Haptic Reliability Introduced by Using a Tool

    Directory of Open Access Journals (Sweden)

    Chie Takahashi

    2011-10-01

    Full Text Available Tools such as pliers systematically change the relationship between an object's size and the hand opening required to grasp it. Previous work suggests the brain takes this into account, integrating visual and haptic size information that refers to the same object, independent of the similarity of the ‘raw’ visual and haptic signals (Takahashi et al., VSS 2009. Variations in tool geometry also affect the reliability (precision of haptic size estimates, however, because they alter the change in hand opening caused by a given change in object size. Here, we examine whether the brain appropriately adjusts the weights given to visual and haptic size signals when tool geometry changes. We first estimated each cue's reliability by measuring size-discrimination thresholds in vision-alone and haptics-alone conditions. We varied haptic reliability using tools with different object-size:hand-opening ratios (1:1, 0.7:1, and 1.4:1. We then measured the weights given to vision and haptics with each tool, using a cue-conflict paradigm. The weight given to haptics varied with tool type in a manner that was well predicted by the single-cue reliabilities (MLE model; Ernst and Banks, 2002. This suggests that the process of visual-haptic integration appropriately accounts for variations in haptic reliability introduced by different tool geometries.

  5. Frictional Compliant Haptic Contact and Deformation of Soft Objects

    Directory of Open Access Journals (Sweden)

    Naci Zafer

    2016-05-01

    Full Text Available This paper is concerned with compliant haptic contact and deformation of soft objects. A human soft fingertip model is considered to act as the haptic interface and is brought into contact with and deforms a discrete surface. A nonlinear constitutive law is developed in predicting normal forces and, for the haptic display of surface texture, motions along the surface are also resisted at various rates by accounting for dynamic Lund-Grenoble (LuGre frictional forces. For the soft fingertip to apply forces over an area larger than a point, normal and frictional forces are distributed around the soft fingertip contact location on the deforming surface. The distribution is realized based on a kernel smoothing function and by a nonlinear spring-damper net around the contact point. Experiments conducted demonstrate the accuracy and effectiveness of our approach in real-time haptic rendering of a kidney surface. The resistive (interaction forces are applied at the user fingertip bone edge. A 3-DoF parallel robotic manipulator equipped with a constraint based controller is used for the implementation. By rendering forces both in lateral and normal directions, the designed haptic interface system allows the user to realistically feel both the geometrical and mechanical (nonlinear properties of the deforming kidney.

  6. OzBot and haptics: remote surveillance to physical presence

    Science.gov (United States)

    Mullins, James; Fielding, Mick; Nahavandi, Saeid

    2009-05-01

    This paper reports on robotic and haptic technologies and capabilities developed for the law enforcement and defence community within Australia by the Centre for Intelligent Systems Research (CISR). The OzBot series of small and medium surveillance robots have been designed in Australia and evaluated by law enforcement and defence personnel to determine suitability and ruggedness in a variety of environments. Using custom developed digital electronics and featuring expandable data busses including RS485, I2C, RS232, video and Ethernet, the robots can be directly connected to many off the shelf payloads such as gas sensors, x-ray sources and camera systems including thermal and night vision. Differentiating the OzBot platform from its peers is its ability to be integrated directly with haptic technology or the 'haptic bubble' developed by CISR. Haptic interfaces allow an operator to physically 'feel' remote environments through position-force control and experience realistic force feedback. By adding the capability to remotely grasp an object, feel its weight, texture and other physical properties in real-time from the remote ground control unit, an operator's situational awareness is greatly improved through Haptic augmentation in an environment where remote-system feedback is often limited.

  7. Effect of haptic assistance on learning vehicle reverse parking skills.

    Science.gov (United States)

    Hirokawa, Masakazu; Uesugi, Naohisa; Furugori, Satoru; Kitagawa, Tomoko; Suzuki, Kenji

    2014-01-01

    Compared to conventional visual- and auditory-based assisted driving technologies, haptic modality promises to be more effective and less disturbing assistance to the driver. However, in most previous studies, haptic assistance systems were evaluated from safety and stability viewpoints. Moreover, the effect of haptic assistance on human driving behavior has not been sufficiently discussed. In this paper, we introduce an assisted driving method based on haptic assistance for driver training in reverse parking, which is considered as an uncertain factor in conventional assisted driving systems. The proposed system assists the driver by applying a torque on the steering wheel to guide proper and well-timed steering. To design the appropriate assistance method, we conducted a measurement experiment to determine the qualitative reverse parking driver characteristics. Based on the determined characteristics, we propose a haptic assistance calculation method that utilizes the receding horizon control algorithm. For a simulation environment to assess the proposed assistance method, we also developed a scaled car simulator comprising a 1/10 scaled robot car and an omnidirectional camera. We used the scaled car simulator to conduct comparative experiments on subjects, and observed that the driving skills of the assisted subjects were significantly better than those of the control subjects.

  8. Higher curvature supergravity and cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Ferrara, Sergio [Th-Ph Department, CERN, Geneva (Switzerland); U.C.L.A., Los Angeles, CA (United States); INFN - LNF, Frascati (Italy); Sagnotti, Augusto [Scuola Normale Superiore, Pisa (Italy); INFN, Pisa (Italy)

    2016-04-15

    In this contribution we describe dual higher-derivative formulations of some cosmological models based on supergravity. Work in this direction started with the R + R{sup 2} Starobinsky model, whose supersymmetric extension was derived in the late 80's and was recently revived in view of new CMB data. Models dual to higher-derivative theories are subject to more restrictions than their bosonic counterparts or standard supergravity. The three sections are devoted to a brief description of R + R{sup 2} supergravity, to a scale invariant R{sup 2} supergravity and to theories with a nilpotent curvature, whose duals describe non-linear realizations (in the form of a Volkov-Akulov constrained superfield) coupled to supergravity. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. SLED phenomenology: curvature vs. volume

    International Nuclear Information System (INIS)

    Niedermann, Florian; Schneider, Robert

    2016-01-01

    We assess the question whether the SLED (Supersymmetric Large Extra Dimensions) model admits phenomenologically viable solutions with 4D maximal symmetry. We take into account a finite brane width and a scale invariance (SI) breaking dilaton-brane coupling, both of which should be included in a realistic setup. Provided that the brane tension and the microscopic size of the brane take generic values set by the fundamental bulk Planck scale, we find that either the 4D curvature or the size of the extra dimensions is unacceptably large. Since this result is independent of the dilaton-brane couplings, it provides the biggest challenge to the SLED program. In addition, to quantify its potential with respect to the cosmological constant problem, we infer the amount of tuning on model parameters required to obtain a sufficiently small 4D curvature. A first answer was recently given in http://dx.doi.org/10.1007/JHEP02(2016)025, showing that 4D flat solutions are only ensured in the SI case by imposing a tuning relation, even if a brane-localized flux is included. In this companion paper, we find that the tuning can in fact be avoided for certain SI breaking brane-dilaton couplings, but only at the price of worsening the phenomenological problem. Our results are obtained by solving the full coupled Einstein-dilaton system in a completely consistent way. The brane width is implemented using a well-known ring regularization. In passing, we note that for the couplings considered here the results of http://dx.doi.org/10.1007/JHEP02(2016)025 (which only treated infinitely thin branes) are all consistently recovered in the thin brane limit, and how this can be reconciled with the concerns about their correctness, recently brought up in http://dx.doi.org/10.1007/JHEP01(2016)017.

  10. Haptic-Multimodal Flight Control System Update

    Science.gov (United States)

    Goodrich, Kenneth H.; Schutte, Paul C.; Williams, Ralph A.

    2011-01-01

    The rapidly advancing capabilities of autonomous aircraft suggest a future where many of the responsibilities of today s pilot transition to the vehicle, transforming the pilot s job into something akin to driving a car or simply being a passenger. Notionally, this transition will reduce the specialized skills, training, and attention required of the human user while improving safety and performance. However, our experience with highly automated aircraft highlights many challenges to this transition including: lack of automation resilience; adverse human-automation interaction under stress; and the difficulty of developing certification standards and methods of compliance for complex systems performing critical functions traditionally performed by the pilot (e.g., sense and avoid vs. see and avoid). Recognizing these opportunities and realities, researchers at NASA Langley are developing a haptic-multimodal flight control (HFC) system concept that can serve as a bridge between today s state of the art aircraft that are highly automated but have little autonomy and can only be operated safely by highly trained experts (i.e., pilots) to a future in which non-experts (e.g., drivers) can safely and reliably use autonomous aircraft to perform a variety of missions. This paper reviews the motivation and theoretical basis of the HFC system, describes its current state of development, and presents results from two pilot-in-the-loop simulation studies. These preliminary studies suggest the HFC reshapes human-automation interaction in a way well-suited to revolutionary ease-of-use.

  11. Vision holds a greater share in visuo-haptic object recognition than touch

    DEFF Research Database (Denmark)

    Kassuba, Tanja; Klinge, Corinna; Hölig, Cordula

    2013-01-01

    approach of multisensory integration would predict that haptics as the less efficient sense for object recognition gains more from integrating additional visual information than vice versa. To test for asymmetries between vision and touch in visuo-haptic interactions, we measured regional changes in brain...... processed the target object, being more pronounced for haptic than visual targets. This preferential response of visuo-haptic regions indicates a modality-specific asymmetry in crossmodal matching of visual and haptic object features, suggesting a functional primacy of vision over touch in visuo...

  12. Conflicting audio-haptic feedback in physically based simulation of walking sounds

    DEFF Research Database (Denmark)

    Turchet, Luca; Serafin, Stefania; Dimitrov, Smilen

    2010-01-01

    We describe an audio-haptic experiment conducted using a system which simulates in real-time the auditory and haptic sensation of walking on different surfaces. The system is based on physical models, that drive both the haptic and audio synthesizers, and a pair of shoes enhanced with sensors...... and actuators. Such experiment was run to examine the ability of subjects to recognize the different surfaces with both coherent and incoherent audio-haptic stimuli. Results show that in this kind of tasks the auditory modality is dominant on the haptic one....

  13. Curvature effects on carbon nanomaterials: Exohedral versus endhohedral supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Huang, J; Sumpter, B. G.; Meunier, V.; Yushin, G.; Portet, C.; Gogotsi, Y.

    2011-01-31

    Capacitive energy storage mechanisms in nanoporous carbon supercapacitors hinge on endohedral interactions in carbon materials with macro-, meso-, and micropores that have negative surface curvature. In this article, we show that because of the positive curvature found in zero-dimensional carbon onions or one-dimensional carbon nanotube arrays, exohedral interactions cause the normalized capacitance to increase with decreasing particle size or tube diameter, in sharp contrast to the behavior of nanoporous carbon materials. This finding is in good agreement with the trend of recent experimental data. Our analysis suggests that electrical energy storage can be improved by exploiting the highly curved surfaces of carbon nanotube arrays with diameters on the order of 1 nm.

  14. Curvature effects in carbon nanomaterials: Exohedral versus endohedral supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Jingsong [ORNL; Sumpter, Bobby G [ORNL; Meunier, Vincent [ORNL; Gogotsi, Yury G. [Drexel University; Yushin, Gleb [Georgia Institute of Technology; Portet, Cristelle [Drexel University

    2010-01-01

    Capacitive energy storage mechanisms in nanoporous carbon supercapacitors hinge on endohedral interactions in carbon materials with macro-, meso-, and micropores that have negative surface curvature. In this article, we show that because of the positive curvature found in zero-dimensional carbon onions or one-dimensional carbon nanotube arrays, exohedral interactions cause the normalized capacitance to increase with decreasing particle size or tube diameter, in sharp contrast to the behavior of nanoporous carbon materials. This finding is in good agreement with the trend of recent experimental data. Our analysis suggests that electrical energy storage can be improved by exploiting the highly curved surfaces of carbon nanotube arrays with diameters on the order of 1 nm.

  15. Contribution to the modeling and the identification of haptic interfaces

    International Nuclear Information System (INIS)

    Janot, A.

    2007-12-01

    This thesis focuses on the modeling and the identification of haptic interfaces using cable drive. An haptic interface is a force feedback device, which enables its user to interact with a virtual world or a remote environment explored by a slave system. It aims at the matching between the forces and displacements given by the user and those applied to virtual world. Usually, haptic interfaces make use of a mechanical actuated structure whose distal link is equipped with a handle. When manipulating this handle to interact with explored world, the user feels the apparent mass, compliance and friction of the interface. This distortion introduced between the operator and the virtual world must be modeled and identified to enhance the design of the interface and develop appropriate control laws. The first approach has been to adapt the modeling and identification methods of rigid and localized flexibilities robots to haptic interfaces. The identification technique makes use of the inverse dynamic model and the linear least squares with the measurements of joint torques and positions. This approach is validated on a single degree of freedom and a three degree of freedom haptic devices. A new identification method needing only torque data is proposed. It is based on a closed loop simulation using the direct dynamic model. The optimal parameters minimize the 2 norms of the error between the actual torque and the simulated torque assuming the same control law and the same tracking trajectory. This non linear least squares problem dramatically is simplified using the inverse model to calculate the simulated torque. This method is validated on the single degree of freedom haptic device and the SCARA robot. (author)

  16. Weyl tensors for asymmetric complex curvatures

    International Nuclear Information System (INIS)

    Oliveira, C.G.

    Considering a second rank Hermitian field tensor and a general Hermitian connection the associated complex curvature tensor is constructed. The Weyl tensor that corresponds to this complex curvature is determined. The formalism is applied to the Weyl unitary field theory and to the Moffat gravitational theory. (Author) [pt

  17. The curvature function in general relativity

    International Nuclear Information System (INIS)

    Hall, G S; MacNay, Lucy

    2006-01-01

    A function, here called the curvature function, is defined and which is constructed explicitly from the type (0, 4) curvature tensor. Although such a function may be defined for any manifold admitting a metric, attention is here concentrated on this function on a spacetime. Some properties of this function are explored and compared with a previous discussion of it given by Petrov

  18. Visual-Haptic Integration: Cue Weights are Varied Appropriately, to Account for Changes in Haptic Reliability Introduced by Using a Tool

    OpenAIRE

    Chie Takahashi; Simon J Watt

    2011-01-01

    Tools such as pliers systematically change the relationship between an object's size and the hand opening required to grasp it. Previous work suggests the brain takes this into account, integrating visual and haptic size information that refers to the same object, independent of the similarity of the ‘raw’ visual and haptic signals (Takahashi et al., VSS 2009). Variations in tool geometry also affect the reliability (precision) of haptic size estimates, however, because they alter the change ...

  19. Self-Control of Haptic Assistance for Motor Learning: Influences of Frequency and Opinion of Utility

    Science.gov (United States)

    Williams, Camille K.; Tseung, Victrine; Carnahan, Heather

    2017-01-01

    Studies of self-controlled practice have shown benefits when learners controlled feedback schedule, use of assistive devices and task difficulty, with benefits attributed to information processing and motivational advantages of self-control. Although haptic assistance serves as feedback, aids task performance and modifies task difficulty, researchers have yet to explore whether self-control over haptic assistance could be beneficial for learning. We explored whether self-control of haptic assistance would be beneficial for learning a tracing task. Self-controlled participants selected practice blocks on which they would receive haptic assistance, while participants in a yoked group received haptic assistance on blocks determined by a matched self-controlled participant. We inferred learning from performance on retention tests without haptic assistance. From qualitative analysis of open-ended questions related to rationales for/experiences of the haptic assistance that was chosen/provided, themes emerged regarding participants’ views of the utility of haptic assistance for performance and learning. Results showed that learning was directly impacted by the frequency of haptic assistance for self-controlled participants only and view of haptic assistance. Furthermore, self-controlled participants’ views were significantly associated with their requested haptic assistance frequency. We discuss these findings as further support for the beneficial role of self-controlled practice for motor learning. PMID:29255438

  20. Communicating Emotion through Haptic Design: A Study Using Physical Keys

    DEFF Research Database (Denmark)

    Kjellerup, Marie Kjær; Larsen, Anne Cathrine; Maier, Anja

    2014-01-01

    This paper explores how designers may communicate with the users of their products through haptic design. More specifically, how tactile properties of materials evoke emotions such as satisfaction, joy, or disgust. A research through design approach has been followed; mood- and material boards...... and prototypes of four ‘haptically enhanced’ (physical) keys were created. Types of keys selected include home, bicycle, hobby, and basement. An experiment with ten participants was conducted, using word association and a software to elicit product emotions (PrEmo). Results show a mapping between the designer...

  1. Haptic Manipulation of Deformable Objects in Hybrid Bilateral Teleoperation System

    Directory of Open Access Journals (Sweden)

    Juan Manuel Ibarra-Zannatha

    2007-01-01

    Full Text Available The aim of this work is the integration of a virtual environment containing a deformable object, manipulated by an open kinematical chain virtual slave robot, to a bilateral teleoperation scheme based on a real haptic device. The virtual environment of this hybrid bilateral teleoperation system combines collision detection algorithms, dynamical, kinematical and geometrical models with a position–position and/or force–position bilateral control algorithm, to produce on the operator side the reflected forces corresponding to the virtual mechanical interactions, through a haptic device. Contact teleoperation task over the virtual environment with a flexible object is implemented and analysed.

  2. The role of haptic feedback in laparoscopic simulation training.

    Science.gov (United States)

    Panait, Lucian; Akkary, Ehab; Bell, Robert L; Roberts, Kurt E; Dudrick, Stanley J; Duffy, Andrew J

    2009-10-01

    Laparoscopic virtual reality simulators are becoming a ubiquitous tool in resident training and assessment. These devices provide the operator with various levels of realism, including haptic (or force) feedback. However, this feature adds significantly to the cost of the devices, and limited data exist assessing the value of haptics in skill acquisition and development. Utilizing the Laparoscopy VR (Immersion Medical, Gaithersburg, MD), we hypothesized that the incorporation of force feedback in the simulated operative environment would allow superior trainee performance compared with performance of the same basic skills tasks in a non-haptic model. Ten medical students with minimal laparoscopic experience and similar baseline skill levels as proven by performance of two fundamentals of laparoscopic surgery (FLS) tasks (peg transfer and cutting drills) voluntarily participated in the study. Each performed two tasks, analogous to the FLS drills, on the Laparoscopy VR at 3 levels of difficulty, based on the established settings of the manufacturer. After achieving familiarity with the device and tasks, the students completed the drills both with and without force feedback. Data on completion time, instrument path length, right and left hand errors, and grasping tension were analyzed. The scores in the haptic-enhanced simulation environment were compared with the scores in the non-haptic model and analyzed utilizing Student's t-test. The peg transfer drill showed no difference in performance between the haptic and non-haptic simulations for all metrics at all three levels of difficulty. For the more complex cutting exercise, the time to complete the tasks was significantly shorter when force feedback was provided, at all levels of difficulty (158+/-56 versus 187+/-51 s, 176+/-49 versus 222+/-68 s, and 275+/-76 versus 422+/-220 s, at levels 1, 2, and 3, respectively, Psimulation did not demonstrate an appreciable performance improvement among our trainees. These data

  3. Curvature function and coarse graining

    International Nuclear Information System (INIS)

    Diaz-Marin, Homero; Zapata, Jose A.

    2010-01-01

    A classic theorem in the theory of connections on principal fiber bundles states that the evaluation of all holonomy functions gives enough information to characterize the bundle structure (among those sharing the same structure group and base manifold) and the connection up to a bundle equivalence map. This result and other important properties of holonomy functions have encouraged their use as the primary ingredient for the construction of families of quantum gauge theories. However, in these applications often the set of holonomy functions used is a discrete proper subset of the set of holonomy functions needed for the characterization theorem to hold. We show that the evaluation of a discrete set of holonomy functions does not characterize the bundle and does not constrain the connection modulo gauge appropriately. We exhibit a discrete set of functions of the connection and prove that in the abelian case their evaluation characterizes the bundle structure (up to equivalence), and constrains the connection modulo gauge up to ''local details'' ignored when working at a given scale. The main ingredient is the Lie algebra valued curvature function F S (A) defined below. It covers the holonomy function in the sense that expF S (A)=Hol(l=∂S,A).

  4. Curvature and torsion in growing actin networks

    International Nuclear Information System (INIS)

    Shaevitz, Joshua W; Fletcher, Daniel A

    2008-01-01

    Intracellular pathogens such as Listeria monocytogenes and Rickettsia rickettsii move within a host cell by polymerizing a comet-tail of actin fibers that ultimately pushes the cell forward. This dense network of cross-linked actin polymers typically exhibits a striking curvature that causes bacteria to move in gently looping paths. Theoretically, tail curvature has been linked to details of motility by considering force and torque balances from a finite number of polymerizing filaments. Here we track beads coated with a prokaryotic activator of actin polymerization in three dimensions to directly quantify the curvature and torsion of bead motility paths. We find that bead paths are more likely to have low rather than high curvature at any given time. Furthermore, path curvature changes very slowly in time, with an autocorrelation decay time of 200 s. Paths with a small radius of curvature, therefore, remain so for an extended period resulting in loops when confined to two dimensions. When allowed to explore a three-dimensional (3D) space, path loops are less evident. Finally, we quantify the torsion in the bead paths and show that beads do not exhibit a significant left- or right-handed bias to their motion in 3D. These results suggest that paths of actin-propelled objects may be attributed to slow changes in curvature, possibly associated with filament debranching, rather than a fixed torque

  5. Right thoracic curvature in the normal spine

    Directory of Open Access Journals (Sweden)

    Masuda Keigo

    2011-01-01

    Full Text Available Abstract Background Trunk asymmetry and vertebral rotation, at times observed in the normal spine, resemble the characteristics of adolescent idiopathic scoliosis (AIS. Right thoracic curvature has also been reported in the normal spine. If it is determined that the features of right thoracic side curvature in the normal spine are the same as those observed in AIS, these findings might provide a basis for elucidating the etiology of this condition. For this reason, we investigated right thoracic curvature in the normal spine. Methods For normal spinal measurements, 1,200 patients who underwent a posteroanterior chest radiographs were evaluated. These consisted of 400 children (ages 4-9, 400 adolescents (ages 10-19 and 400 adults (ages 20-29, with each group comprised of both genders. The exclusion criteria were obvious chest and spinal diseases. As side curvature is minimal in normal spines and the range at which curvature is measured is difficult to ascertain, first the typical curvature range in scoliosis patients was determined and then the Cobb angle in normal spines was measured using the same range as the scoliosis curve, from T5 to T12. Right thoracic curvature was given a positive value. The curve pattern was organized in each collective three groups: neutral (from -1 degree to 1 degree, right (> +1 degree, and left ( Results In child group, Cobb angle in left was 120, in neutral was 125 and in right was 155. In adolescent group, Cobb angle in left was 70, in neutral was 114 and in right was 216. In adult group, Cobb angle in left was 46, in neutral was 102 and in right was 252. The curvature pattern shifts to the right side in the adolescent group (p Conclusions Based on standing chest radiographic measurements, a right thoracic curvature was observed in normal spines after adolescence.

  6. A non-differential elastomer curvature sensor for softer-than-skin electronics

    International Nuclear Information System (INIS)

    Majidi, C; Kramer, R; Wood, R J

    2011-01-01

    We extend soft lithography microfabrication and design methods to introduce curvature sensors that are elastically soft (modulus 0.1–1 MPa) and stretchable (100–1000% strain). In contrast to existing curvature sensors that measure differential strain, sensors in this new class measure curvature directly and allow for arbitrary gauge factor and film thickness. Moreover, each sensor is composed entirely of a soft elastomer (PDMS (polydimethylsiloxane) or Ecoflex ® ) and conductive liquid (eutectic gallium indium, eGaIn) and thus remains functional even when stretched to several times its natural length. The electrical resistance in the embedded eGaIn microchannel is measured as a function of the bending curvature for a variety of sensor designs. In all cases, the experimental measurements are in reasonable agreement with closed-form algebraic approximations derived from elastic plate theory and Ohm's law

  7. A non-differential elastomer curvature sensor for softer-than-skin electronics

    Science.gov (United States)

    Majidi, C.; Kramer, R.; Wood, R. J.

    2011-10-01

    We extend soft lithography microfabrication and design methods to introduce curvature sensors that are elastically soft (modulus 0.1-1 MPa) and stretchable (100-1000% strain). In contrast to existing curvature sensors that measure differential strain, sensors in this new class measure curvature directly and allow for arbitrary gauge factor and film thickness. Moreover, each sensor is composed entirely of a soft elastomer (PDMS (polydimethylsiloxane) or Ecoflex®) and conductive liquid (eutectic gallium indium, eGaIn) and thus remains functional even when stretched to several times its natural length. The electrical resistance in the embedded eGaIn microchannel is measured as a function of the bending curvature for a variety of sensor designs. In all cases, the experimental measurements are in reasonable agreement with closed-form algebraic approximations derived from elastic plate theory and Ohm's law.

  8. Perceptual grouping affects haptic enumeration over the fingers

    NARCIS (Netherlands)

    Overvliet, K.E.; Plaisier, M.A.

    2016-01-01

    Spatial arrangement is known to influence enumeration times in vision. In haptic enumeration, it has been shown that dividing the total number of items over the two hands can speed up enumeration. Here we investigated how spatial arrangement of items and non-items presented to the individual fingers

  9. Haptic feedback for enhancing realism of walking simulations.

    Science.gov (United States)

    Turchet, Luca; Burelli, Paolo; Serafin, Stefania

    2013-01-01

    In this paper, we describe several experiments whose goal is to evaluate the role of plantar vibrotactile feedback in enhancing the realism of walking experiences in multimodal virtual environments. To achieve this goal we built an interactive and a noninteractive multimodal feedback system. While during the use of the interactive system subjects physically walked, during the use of the noninteractive system the locomotion was simulated while subjects were sitting on a chair. In both the configurations subjects were exposed to auditory and audio-visual stimuli presented with and without the haptic feedback. Results of the experiments provide a clear preference toward the simulations enhanced with haptic feedback showing that the haptic channel can lead to more realistic experiences in both interactive and noninteractive configurations. The majority of subjects clearly appreciated the added feedback. However, some subjects found the added feedback unpleasant. This might be due, on one hand, to the limits of the haptic simulation and, on the other hand, to the different individual desire to be involved in the simulations. Our findings can be applied to the context of physical navigation in multimodal virtual environments as well as to enhance the user experience of watching a movie or playing a video game.

  10. Haptic perception disambiguates visual perception of 3D shape

    NARCIS (Netherlands)

    Wijntjes, Maarten W A; Volcic, Robert; Pont, Sylvia C.; Koenderink, Jan J.; Kappers, Astrid M L

    We studied the influence of haptics on visual perception of three-dimensional shape. Observers were shown pictures of an oblate spheroid in two different orientations. A gauge-figure task was used to measure their perception of the global shape. In the first two sessions only vision was used. The

  11. Haptic virtual reality for skill acquisition in endodontics.

    Science.gov (United States)

    Suebnukarn, Siriwan; Haddawy, Peter; Rhienmora, Phattanapon; Gajananan, Kugamoorthy

    2010-01-01

    Haptic virtual reality (VR) has revolutionized the skill acquisition in dentistry. The strength of the haptic VR system is that it can automatically record the outcome and associated kinematic data on how each step of the task is performed, which are not available in the conventional skill training environments. The aim of this study was to assess skill acquisition in endodontics and to identify process and outcome variables for the quantification of proficiency. Twenty novices engaged in the experimental study that involved practicing the access opening task with the haptic VR system. Process (speed, force utilization, and bimanual coordination) and outcome variables were determined for assessing skill performance. These values were compared before and after training. Significant improvements were observed through training in all variables. A unique force used pattern and bimanual coordination were observed in each step of the access opening in the posttraining session. The novices also performed the tasks considerably faster with greater outcome within the first two to three training sessions. The study objectively showed that the novices could learn to perform access opening tasks faster and with more consistency, better bimanual dexterity, and better force utilization. The variables examined showed great promise as objective indicators of proficiency and skill acquisition in haptic VR.

  12. The C-Lever Project: Haptics for Automotive Applications

    NARCIS (Netherlands)

    Garcia Canseco, E.; Ayemlong Fokem, A.; Serrarens, A.F.A.; Steinbuch, M.; Stigter, H.

    2010-01-01

    The goal of this project is to research the effectiveness of a controlled haptic force feedback shift lever that can accurately reproduce the behavior of a manual gear shift during driving, and that can also be used to control interior and comfort functions in the car.

  13. Towards a standard on evaluation of tactile/haptic interactions

    NARCIS (Netherlands)

    Sinclair, I.; Carter, J.; Kassner, S.; Erp, J.B.F. van; Weber, G.; Elliott, L.; Andrew, I.

    2012-01-01

    Tactile and haptic interaction is becoming increasingly important; ergonomic standards can ensure that systems are designed with sufficient concern for ergonomics and interoperability. ISO (through working group TC159/SC4/WG9) is developing international standards in this subject area, dual-tracked

  14. Adapting haptic guidance authority based on user grip

    NARCIS (Netherlands)

    Smisek, J.; Mugge, W.; Smeets, J.B.J.; Van Paassen, M.M.; Schiele, A

    2014-01-01

    Haptic guidance systems support the operator in task execution using additional forces on the input device. Scaling of the guidance forces determines the control authority of the support system. As task complexity may vary, one level of the guidance scaling may be insufficient, and adaptation of the

  15. Neodymium:YAG laser cutting of intraocular lens haptics.

    Science.gov (United States)

    Gorn, R A; Steinert, R F

    1985-11-01

    Neodymium:YAG laser cutting of polymethylmethacrylate and polypropylene anterior chamber and posterior chamber intraocular lens haptics was studied in terms of ease of transection and physical structure of the cut areas as seen by scanning electron microscopy. A marked difference was discovered, with the polymethylmethacrylate cutting easily along transverse planes, whereas the polypropylene resisted cutting along longitudinal fibers. Clinical guidelines are presented.

  16. The Use of Haptic Display Technology in Education

    Science.gov (United States)

    Barfield, Woodrow

    2009-01-01

    The experience of "virtual reality" can consist of head-tracked and stereoscopic virtual worlds, spatialized sound, haptic feedback, and to a lesser extent olfactory cues. Although virtual reality systems have been proposed for numerous applications, the field of education is one particular application that seems well-suited for virtual…

  17. Multisensory Interactions between Auditory and Haptic Object Recognition

    DEFF Research Database (Denmark)

    Kassuba, Tanja; Menz, Mareike M; R�der, Brigitte

    2013-01-01

    and haptic object features activate cortical regions that host unified conceptual object representations. The left fusiform gyrus (FG) and posterior superior temporal sulcus (pSTS) showed increased activation during crossmodal matching of semantically congruent but not incongruent object stimuli. In the FG...

  18. The mere exposure effect in the domain of haptics.

    Science.gov (United States)

    Jakesch, Martina; Carbon, Claus-Christian

    2012-01-01

    Zajonc showed that the attitude towards stimuli that one had been previously exposed to is more positive than towards novel stimuli. This mere exposure effect (MEE) has been tested extensively using various visual stimuli. Research on the MEE is sparse, however, for other sensory modalities. We used objects of two material categories (stone and wood) and two complexity levels (simple and complex) to test the influence of exposure frequency (F0 = novel stimuli, F2 = stimuli exposed twice, F10 = stimuli exposed ten times) under two sensory modalities (haptics only and haptics & vision). Effects of exposure frequency were found for high complex stimuli with significantly increasing liking from F0 to F2 and F10, but only for the stone category. Analysis of "Need for Touch" data showed the MEE in participants with high need for touch, which suggests different sensitivity or saturation levels of MEE. This different sensitivity or saturation levels might also reflect the effects of expertise on the haptic evaluation of objects. It seems that haptic and cross-modal MEEs are influenced by factors similar to those in the visual domain indicating a common cognitive basis.

  19. The mere exposure effect in the domain of haptics.

    Directory of Open Access Journals (Sweden)

    Martina Jakesch

    Full Text Available Zajonc showed that the attitude towards stimuli that one had been previously exposed to is more positive than towards novel stimuli. This mere exposure effect (MEE has been tested extensively using various visual stimuli. Research on the MEE is sparse, however, for other sensory modalities.We used objects of two material categories (stone and wood and two complexity levels (simple and complex to test the influence of exposure frequency (F0 = novel stimuli, F2 = stimuli exposed twice, F10 = stimuli exposed ten times under two sensory modalities (haptics only and haptics & vision. Effects of exposure frequency were found for high complex stimuli with significantly increasing liking from F0 to F2 and F10, but only for the stone category. Analysis of "Need for Touch" data showed the MEE in participants with high need for touch, which suggests different sensitivity or saturation levels of MEE.This different sensitivity or saturation levels might also reflect the effects of expertise on the haptic evaluation of objects. It seems that haptic and cross-modal MEEs are influenced by factors similar to those in the visual domain indicating a common cognitive basis.

  20. Real-time vision, tactile cues, and visual form agnosia in pantomimed grasping: removing haptic feedback induces a switch from natural to pantomime-like grasps

    Directory of Open Access Journals (Sweden)

    Robert Leslie Whitwell

    2015-05-01

    Full Text Available Investigators study the kinematics of grasping movements (prehension under a variety of conditions to probe visuomotor function in normal and brain-damaged individuals. When patient DF, who suffers from visual form agnosia, performs natural grasps, her in-flight hand aperture is scaled to the widths of targets ('grip scaling' that she cannot discriminate amongst. In contrast, when DF's pantomime grasps are based on a memory of a previewed object, her grip scaling is very poor. Her failure on this task has been interpreted as additional support for the dissociation between the use of object vision for action and object vision for perception. Curiously, however, when DF directs her pantomimed grasps towards a displaced imagined copy of a visible object where her fingers make contact with the surface of the table, her grip scaling does not appear to be particularly poor. In the first of two experiments, we revisit this previous work and show that her grip scaling in this real-time pantomime grasping task does not differ from controls, suggesting that terminal tactile feedback from a proxy of the target can maintain DF's grip scaling. In a second experiment with healthy participants, we tested a recent variant of a grasping task in which no tactile feedback is available (i.e. no haptic feedback by comparing the kinematics of target-directed grasps with and without haptic feedback to those of real-time pantomime grasps without haptic feedback. Compared to natural grasps, removing haptic feedback increased RT, slowed the velocity of the reach, reduced grip aperture, sharpened the slopes relating grip aperture to target width, and reduced the final grip aperture. All of these effects were also observed in the pantomime grasping task. Taken together, these results provide compelling support for the view that removing haptic feedback induces a switch from real-time visual control to one that depends more on visual perception and cognitive supervision.

  1. Audio effects on haptics perception during drilling simulation

    Directory of Open Access Journals (Sweden)

    Yair Valbuena

    2017-06-01

    Full Text Available Virtual reality has provided immersion and interactions through computer generated environments attempting to reproduce real life experiences through sensorial stimuli. Realism can be achieved through multimodal interactions which can enhance the user’s presence within the computer generated world. The most notorious advances in virtual reality can be seen in computer graphics visuals, where photorealism is the norm thriving to overcome the uncanny valley. Other advances have followed related to sound, haptics, and in a lesser manner smell and taste feedback. Currently, virtual reality systems (multimodal immersion and interactions through visual-haptic-sound are being massively used in entertainment (e.g., cinema, video games, art, and in non-entertainment scenarios (e.g., social inclusion, educational, training, therapy, and tourism. Moreover, the cost reduction of virtual reality technologies has resulted in the availability at a consumer-level of various haptic, headsets, and motion tracking devices. Current consumer-level devices offer low-fidelity experiences due to the properties of the sensors, displays, and other electro-mechanical devices, that may not be suitable for high-precision or realistic experiences requiring dexterity. However, research has been conducted on how toovercome or compensate the lack of high fidelity to provide an engaging user experience using storytelling, multimodal interactions and gaming elements. Our work focuses on analyzing the possible effects of auditory perception on haptic feedback within a drilling scenario. Drilling involves multimodal interactions and it is a task with multiple applications in medicine, crafting, and construction. We compare two drilling scenarios were two groups of participants had to drill through wood while listening to contextual and non-contextual audios. We gathered their perception using a survey after the task completion. From the results, we believe that sound does

  2. Human haptic perception is interrupted by explorative stops of milliseconds

    Directory of Open Access Journals (Sweden)

    Martin eGrunwald

    2014-04-01

    Full Text Available Introduction: The explorative scanning movements of the hands have been compared to those of the eyes. The visual process is known to be composed of alternating phases of saccadic eye movements and fixation pauses. Descriptive results suggest that during the haptic exploration of objects short movement pauses occur as well. The goal of the present study was to detect these explorative stops (ES during one-handed and two-handed haptic explorations of various objects and patterns, and to measure their duration. Additionally, the associations between the following variables were analyzed: a between mean exploration time and duration of ES, b between certain stimulus features and ES frequency, and c the duration of ES during the course of exploration. Methods: Five different experiments were used. The first two experiments were classical recognition tasks of unknown haptic stimuli (A and of common objects (B. In experiment C space-position information of angle legs had to be perceived and reproduced. For experiments D and E the PHANToM haptic device was used for the exploration of virtual (D and real (E sunken reliefs. Results: In each experiment we observed explorative stops of different average durations. For experiment A: 329.50 ms, experiment B: 67.47 ms, experiment C: 189.92 ms, experiment D: 186.17 ms and experiment E: 140.02 ms. Significant correlations were observed between exploration time and the duration of the ES. Also, ES occurred more frequently, but not exclusively, at defined stimulus features like corners, curves and the endpoints of lines. However, explorative stops do not occur every time a stimulus feature is explored. Conclusions: We assume that ES are a general aspect of human haptic exploration processes. We have tried to interpret the occurrence and duration of ES with respect to the Hypotheses-Rebuild-Model and the Limited Capacity Control System theory.

  3. Discrete Curvatures and Discrete Minimal Surfaces

    KAUST Repository

    Sun, Xiang

    2012-01-01

    This thesis presents an overview of some approaches to compute Gaussian and mean curvature on discrete surfaces and discusses discrete minimal surfaces. The variety of applications of differential geometry in visualization and shape design leads

  4. Higher Curvature Supergravity, Supersymmetry Breaking and Inflation

    CERN Document Server

    Ferrara, Sergio

    2017-01-01

    In these lectures, after a short introduction to cosmology, we discuss the supergravity embedding of higher curvature models of inflation. The supergravity description of such models is presented for the two different formulations of minimal supergravity.

  5. Curvature of Indoor Sensor Network: Clustering Coefficient

    Directory of Open Access Journals (Sweden)

    2009-03-01

    Full Text Available We investigate the geometric properties of the communication graph in realistic low-power wireless networks. In particular, we explore the concept of the curvature of a wireless network via the clustering coefficient. Clustering coefficient analysis is a computationally simplified, semilocal approach, which nevertheless captures such a large-scale feature as congestion in the underlying network. The clustering coefficient concept is applied to three cases of indoor sensor networks, under varying thresholds on the link packet reception rate (PRR. A transition from positive curvature (“meshed” network to negative curvature (“core concentric” network is observed by increasing the threshold. Even though this paper deals with network curvature per se, we nevertheless expand on the underlying congestion motivation, propose several new concepts (network inertia and centroid, and finally we argue that greedy routing on a virtual positively curved network achieves load balancing on the physical network.

  6. The spinning particle with extrinsic curvature

    International Nuclear Information System (INIS)

    Dhar, A.

    1988-01-01

    We construct and analyse an action for the spinning particle which contains an extrinsic curvature term. A possible generalization of this construction to the case of the spinning string is also discussed. (orig.)

  7. Different haptic tools reduce trunk velocity in the frontal plane during walking, but haptic anchors have advantages over lightly touching a railing.

    Science.gov (United States)

    Hedayat, Isabel; Moraes, Renato; Lanovaz, Joel L; Oates, Alison R

    2017-06-01

    There are different ways to add haptic input during walking which may affect walking balance. This study compared the use of two different haptic tools (rigid railing and haptic anchors) and investigated whether any effects on walking were the result of the added sensory input and/or the posture generated when using those tools. Data from 28 young healthy adults were collected using the Mobility Lab inertial sensor system (APDM, Oregon, USA). Participants walked with and without both haptic tools and while pretending to use both haptic tools (placebo trials), with eyes opened and eyes closed. Using the tools or pretending to use both tools decreased normalized stride velocity (p  .999). These findings highlight a difference in the type of tool used to add haptic input and suggest that changes in balance control strategy resulting from using the railing are based on arm placement, where it is the posture combined with added sensory input that affects balance control strategies with the haptic anchors. These findings provide a strong framework for additional research to be conducted on the effects of haptic input on walking in populations known to have decreased walking balance.

  8. Straight-line string with curvature

    International Nuclear Information System (INIS)

    Solov'ev, L.D.

    1995-01-01

    Classical and quantum solutions for the relativistic straight-line string with arbitrary dependence on the world surface curvature are obtained. They differ from the case of the usual Nambu-Goto interaction by the behaviour of the Regge trajectory which in general can be non-linear. A regularization of the action is considered and a comparison with relativistic point with curvature is made. 5 refs

  9. Curvature-Induced Instabilities of Shells

    Science.gov (United States)

    Pezzulla, Matteo; Stoop, Norbert; Steranka, Mark P.; Bade, Abdikhalaq J.; Holmes, Douglas P.

    2018-01-01

    Induced by proteins within the cell membrane or by differential growth, heating, or swelling, spontaneous curvatures can drastically affect the morphology of thin bodies and induce mechanical instabilities. Yet, the interaction of spontaneous curvature and geometric frustration in curved shells remains poorly understood. Via a combination of precision experiments on elastomeric spherical shells, simulations, and theory, we show how a spontaneous curvature induces a rotational symmetry-breaking buckling as well as a snapping instability reminiscent of the Venus fly trap closure mechanism. The instabilities, and their dependence on geometry, are rationalized by reducing the spontaneous curvature to an effective mechanical load. This formulation reveals a combined pressurelike term in the bulk and a torquelike term in the boundary, allowing scaling predictions for the instabilities that are in excellent agreement with experiments and simulations. Moreover, the effective pressure analogy suggests a curvature-induced subcritical buckling in closed shells. We determine the critical buckling curvature via a linear stability analysis that accounts for the combination of residual membrane and bending stresses. The prominent role of geometry in our findings suggests the applicability of the results over a wide range of scales.

  10. End-to-End Flow Control for Visual-Haptic Communication under Bandwidth Change

    Science.gov (United States)

    Yashiro, Daisuke; Tian, Dapeng; Yakoh, Takahiro

    This paper proposes an end-to-end flow controller for visual-haptic communication. A visual-haptic communication system transmits non-real-time packets, which contain large-size visual data, and real-time packets, which contain small-size haptic data. When the transmission rate of visual data exceeds the communication bandwidth, the visual-haptic communication system becomes unstable owing to buffer overflow. To solve this problem, an end-to-end flow controller is proposed. This controller determines the optimal transmission rate of visual data on the basis of the traffic conditions, which are estimated by the packets for haptic communication. Experimental results confirm that in the proposed method, a short packet-sending interval and a short delay are achieved under bandwidth change, and thus, high-precision visual-haptic communication is realized.

  11. Haptic sensitivity in needle insertion: the effects of training and visual aid

    Directory of Open Access Journals (Sweden)

    Dumas Cedric

    2011-12-01

    Full Text Available This paper describes an experiment conducted to measure haptic sensitivity and the effects of haptic training with and without visual aid. The protocol for haptic training consisted of a needle insertion task using dual-layer silicon samples. A visual aid was provided as a multimodal cue for the haptic perception task. Results showed that for a group of novices (subjects with no previous experience in needle insertion, training with a visual aid resulted in a longer time to task completion, and a greater applied force, during post-training tests. This suggests that haptic perception is easily overshadowed, and may be completely replaced, by visual feedback. Therefore, haptic skills must be trained differently from visuomotor skills.

  12. Haptic Data Processing for Teleoperation Systems: Prediction, Compression and Error Correction

    OpenAIRE

    Lee, Jae-young

    2013-01-01

    This thesis explores haptic data processing methods for teleoperation systems, including prediction, compression, and error correction. In the proposed haptic data prediction method, unreliable network conditions, such as time-varying delay and packet loss, are detected by a transport layer protocol. Given the information from the transport layer, a Bayesian approach is introduced to predict position and force data in haptic teleoperation systems. Stability of the proposed method within stoch...

  13. A Study of an Assistance SystemUsing a Haptic Interface

    OpenAIRE

    浅川, 貴史

    2011-01-01

    We make a proposal for a music baton system for visual handicapped persons. This system is constituted by an acceleration sensor. a radio module. and a haptic interface device. The acceleration sensor is built in the music baton grip and the data are transmitted by the radio module. A performer has a receiver with the haptic interface device. The receiver's CPU picks up rhythm from the data and vibrates the haptic interface device. This paper is described about an experiment of comparing the ...

  14. The haptic and the visual flash-lag effect and the role of flash characteristics.

    Directory of Open Access Journals (Sweden)

    Knut Drewing

    Full Text Available When a short flash occurs in spatial alignment with a moving object, the moving object is seen ahead the stationary one. Similar to this visual "flash-lag effect" (FLE it has been recently observed for the haptic sense that participants judge a moving hand to be ahead a stationary hand when judged at the moment of a short vibration ("haptic flash" that is applied when the two hands are spatially aligned. We further investigated the haptic FLE. First, we compared participants' performance in two isosensory visual or haptic conditions, in which moving object and flash were presented only in a single modality (visual: sphere and short color change, haptic: hand and vibration, and two bisensory conditions, in which the moving object was presented in both modalities (hand aligned with visible sphere, but the flash was presented only visually or only haptically. The experiment aimed to disentangle contributions of the flash's and the objects' modalities to the FLEs in haptics versus vision. We observed a FLE when the flash was visually displayed, both when the moving object was visual and visuo-haptic. Because the position of a visual flash, but not of an analogue haptic flash, is misjudged relative to a same visuo-haptic moving object, the difference between visual and haptic conditions can be fully attributed to characteristics of the flash. The second experiment confirmed that a haptic FLE can be observed depending on flash characteristics: the FLE increases with decreasing intensity of the flash (slightly modulated by flash duration, which had been previously observed for vision. These findings underline the high relevance of flash characteristics in different senses, and thus fit well with the temporal-sampling framework, where the flash triggers a high-level, supra-modal process of position judgement, the time point of which further depends on the processing time of the flash.

  15. HSP v2: Haptic Signal Processing with Extensions for Physical Modeling

    DEFF Research Database (Denmark)

    Overholt, Daniel; Kontogeorgakopoulos, Alexandros; Berdahl, Edgar

    2010-01-01

    The Haptic Signal Processing (HSP) platform aims to enable musicians to easily design and perform with digital haptic musical instruments [1]. In this paper, we present some new objects introduced in version v2 for modeling of musical dynamical systems such as resonators and vibrating strings. To....... To our knowledge, this is the first time that these diverse physical modeling elements have all been made available for a modular, real-time haptics platform....

  16. The Hedonic Haptics Player: A Wearable Device to Experience Vibrotactile Compositions

    OpenAIRE

    Boer, Laurens; Vallgårda, Anna; Cahill, Ben

    2017-01-01

    The Hedonic Haptics player is a portable wearable device that plays back vibrotactile compositions. It consists of three domes each of which houses a vibration motor providing vibrotactile sensations to the wearer. The domes are connected to a control unit the size of a small Walkman. The Hedonic Haptics player can store up to ten different compositions made up of haptic signals varying in amplitude, waveform and length. We use these different compositions to explore the aesthetic potential o...

  17. Distal root curvatures in mandibular molars: analysis using digital panoramic X-rays.

    Science.gov (United States)

    Fuentes, R; Farfán, C; Astete, N; Navarro, P; Arias, A

    2018-01-01

    The aim of this study was to describe the degree of curvature in distal roots in the first and second permanent mandibular molars in a Chilean patient sample. A cross-sectional descriptive study was conducted in which digital panoramic X-rays were analysed. Examinations of patients under 18 years, with signs of distortion or alteration in the contrast or the presence of pathologies that affected visualisation of the roots and pulp-chamber floor of the teeth to be analysed were excluded. Using the AutoCad software, an angle was drawn to represent the curve of the root in its different thirds, drawing lines inside the root canal from the pulp-chamber floor to the dental apex. Using the classic definition of dilaceration (root curvature > 90°), its prevalence was established. 412 teeth and roots were analysed, finding a dilaceration prevalence of 0.73% (n = 3). 84.72% of the roots presented some type of curvature. The middle third had the highest percentage of curvatures and the greatest average of angular curvature, whereas the cervical third was the straightest. No significant differences were found between the degree of curvature and the gender of the subjects, except for the apical third of tooth 3.6. The analysis of curvature by root third offers to the clinician a better perspective of the directional change of the roots and does not limit it to just the presence of curves in the apical third. The report of the angular degree of the curvatures, in addition to the prevalence of dilacerations, informs to the clinicians about the likelihood of finding difficulties when treating root canals. (Folia Morphol 2018; 77, 1: 131-137).

  18. A novel shape-changing haptic table-top display

    Science.gov (United States)

    Wang, Jiabin; Zhao, Lu; Liu, Yue; Wang, Yongtian; Cai, Yi

    2018-01-01

    A shape-changing table-top display with haptic feedback allows its users to perceive 3D visual and texture displays interactively. Since few existing devices are developed as accurate displays with regulatory haptic feedback, a novel attentive and immersive shape changing mechanical interface (SCMI) consisting of image processing unit and transformation unit was proposed in this paper. In order to support a precise 3D table-top display with an offset of less than 2 mm, a custommade mechanism was developed to form precise surface and regulate the feedback force. The proposed image processing unit was capable of extracting texture data from 2D picture for rendering shape-changing surface and realizing 3D modeling. The preliminary evaluation result proved the feasibility of the proposed system.

  19. Short-term plasticity of visuo-haptic object recognition

    DEFF Research Database (Denmark)

    Kassuba, Tanja; Klinge, Corinna; Hölig, Cordula

    2014-01-01

    , the same stimulation gave rise to relative increases in activation during S2 processing in the right LO, left FG, bilateral IPS, and other regions previously associated with object recognition. Critically, the modality of S2 determined which regions were recruited after rTMS. Relative to sham rTMS, real r......TMS induced increased activations during crossmodal congruent matching in the left FG for haptic S2 and the temporal pole for visual S2. In addition, we found stronger activations for incongruent than congruent matching in the right anterior parahippocampus and middle frontal gyrus for crossmodal matching......Functional magnetic resonance imaging (fMRI) studies have provided ample evidence for the involvement of the lateral occipital cortex (LO), fusiform gyrus (FG), and intraparietal sulcus (IPS) in visuo-haptic object integration. Here we applied 30 min of sham (non-effective) or real offline 1 Hz...

  20. Listening to white noise counteracts visual and haptic pseudoneglect.

    Science.gov (United States)

    Cattaneo, Zaira; Lega, Carlotta; Vecchi, Tomaso; Vallar, Giuseppe

    2012-01-01

    Neurologically intact individuals usually show a leftward bias in line bisection, a tendency known as "pseudoneglect", likely reflecting a right-hemisphere dominance in controlling the allocation of spatial attention. Studies in brain-damaged patients with left visuospatial neglect have reported that auditory stimulation may reduce the deficit, both in a spatially dependent and in a spatially independent way. Here we show for the first time that the concurrent binaural presentation of auditory white noise affects healthy individuals' performance in both visual and haptic bisection, reducing their leftward error. We suggest that this effect depends on the noise boosting alertness and restoring the hemispheric activation balance. Our data clearly show that task-irrelevant auditory noise crossmodally affects the allocation of spatial resources in both the haptic and the visual space; future research may clarify whether these effects are specific for the type of auditory stimulation.

  1. Curvature constraints from the causal entropic principle

    International Nuclear Information System (INIS)

    Bozek, Brandon; Albrecht, Andreas; Phillips, Daniel

    2009-01-01

    Current cosmological observations indicate a preference for a cosmological constant that is drastically smaller than what can be explained by conventional particle physics. The causal entropic principle (Bousso et al.) provides an alternative approach to anthropic attempts to predict our observed value of the cosmological constant by calculating the entropy created within a causal diamond. We have extended this work to use the causal entropic principle to predict the preferred curvature within the 'multiverse'. We have found that values larger than ρ k =40ρ m are disfavored by more than 99.99% peak value at ρ Λ =7.9x10 -123 and ρ k =4.3ρ m for open universes. For universes that allow only positive curvature or both positive and negative curvature, we find a correlation between curvature and dark energy that leads to an extended region of preferred values. Our universe is found to be disfavored to an extent depending on the priors on curvature. We also provide a comparison to previous anthropic constraints on open universes and discuss future directions for this work.

  2. Some Inequalities for the Lp-Curvature Image

    Directory of Open Access Journals (Sweden)

    Xiang Yu

    2009-01-01

    Full Text Available Lutwak introduced the notion of Lp-curvature image and proved an inequality for the volumes of convex body and its Lp-curvature image. In this paper, we first give an monotonic property of Lp-curvature image. Further, we establish two inequalities for the Lp-curvature image and its polar, respectively. Finally, an inequality for the volumes of Lp-projection body and Lp-curvature image is obtained.

  3. The Effect of Trial-by-trial Adaptation on Conflicts in Haptic Shared Control for Free-Air Teleoperation Tasks

    NARCIS (Netherlands)

    de Jonge, A. W.; Wildenbeest, J. G. W.; Boessenkool, H.; Abbink, D. A.

    2016-01-01

    Haptic shared control can improve execution of teleoperation and driving tasks. However, shared control designs may suffer from conflicts between individual human operators and constant haptic assistance when their desired trajectories differ, leading to momentarily increased forces, discomfort or

  4. Control of 4-DOF MR haptic master for medical application

    Science.gov (United States)

    Oh, Jong-Seok; Choi, Seung-Hyun; Choi, Seung-Bok

    2014-03-01

    In this work, magnetorheological (MR) based haptic master for robot-assisted minimally invasive surgery (RMIS) is proposed and analyzed. Using a controllable MR fluid, the masters can generate a reflection force with the 4-DOF motion. The proposed master consists of two actuators: MR clutch featuring gimbal mechanism for 2-DOF rotational motion (X and Y axes) and MR clutch attached at gripper of gimbal structures for 1-DOF rotational motion (Z axis) and 1-DOF translational motion. After analyzing the dynamic motion by integrating mechanical and physical properties of the actuators, torque model of the proposed haptic master is derived. For realization of master-slave system, an encoder which can measure position information is integrated with the MR haptic master. In the RMIS system, the measured position is converted as a command signal and sent to the slave robot. In this work, slave and organ of patient are modeled in virtual space. In order to embody a human organ into virtual space, a volumetric deformable object is mathematically formulated by a shape retaining chain linked (S-chain) model. Accordingly, the haptic architecture is established by incorporating the virtual slave with the master device in which the reflection force and desired position originated from the object of the virtual slave and operator of the master, respectively, are transferred to each other. In order to achieve the desired force trajectories, a proportional-integral-derivative (PID) controller is designed and implemented. It has been demonstrated that the effective tracking control performance for the desired motion of reflection force is well presented in time domain.

  5. Proximity: representations of fragile space through hapticity and vision

    OpenAIRE

    Garrett, Stephen Francis

    2017-01-01

    This research paper investigates the phenomenology of touch and its relationship to my sculptural practice. My studio research has been engaged in site-responsive interventions developed as a series of ephemeral artworks. Core to this is the relationship between vision and touch. My paper charts the evolution of this and how I consider these factors when making art. My process stems from my engagement with the notion of hapticity-how we understand the tactile experience of space and place ...

  6. Augmented communication with haptic I/O in mobile devices

    OpenAIRE

    Haverinen, Laura

    2012-01-01

    Nonverbal communication is a very important part of face to face communication. Both explicit and implicit additions to verbal communication augment the information content of communication. Before telephones did not provide any means for adding nonverbal information to the communication, but now, as the technology has advanced, it is possible to start augmenting also the communication on the phone. Adding a haptic I/O device to a regular mobile phone opens possibilities to add value to commu...

  7. Development of a new haptic perception instrument: a pilot study

    OpenAIRE

    Nascimento, Leonardo Penteado; Martini, Joyce; Voos, Mariana Callil; Chien, Hsin Fen; Caromano, Fátima Aparecida

    2015-01-01

    ABSTRACT Objective Hand sensory tests do not consider distinct physiological receptors, nor detect normal range variations concerning developmental or pathological changes. We developed an instrument with a set of tests with timing and scoring for assessing haptic perception, which is the interaction between sensory and motor systems, in surfaces exploration, by moving hands. Method Firstly, group meetings were set for test/manual conception and materials testing. The test/manual were sub...

  8. Design and Calibration of a New 6 DOF Haptic Device

    Directory of Open Access Journals (Sweden)

    Huanhuan Qin

    2015-12-01

    Full Text Available For many applications such as tele-operational robots and interactions with virtual environments, it is better to have performance with force feedback than without. Haptic devices are force reflecting interfaces. They can also track human hand positions simultaneously. A new 6 DOF (degree-of-freedom haptic device was designed and calibrated in this study. It mainly contains a double parallel linkage, a rhombus linkage, a rotating mechanical structure and a grasping interface. Benefited from the unique design, it is a hybrid structure device with a large workspace and high output capability. Therefore, it is capable of multi-finger interactions. Moreover, with an adjustable base, operators can change different postures without interrupting haptic tasks. To investigate the performance regarding position tracking accuracy and static output forces, we conducted experiments on a three-dimensional electric sliding platform and a digital force gauge, respectively. Displacement errors and force errors are calculated and analyzed. To identify the capability and potential of the device, four application examples were programmed.

  9. Topographic modelling of haptic properties of tissue products

    International Nuclear Information System (INIS)

    Rosen, B-G; Fall, A; Farbrot, A; Bergström, P; Rosen, S

    2014-01-01

    The way a product or material feels when touched, haptics, has been shown to be a property that plays an important role when consumers determine the quality of products For tissue products in constant touch with the skin, ''softness'' becomes a primary quality parameter. In the present work, the relationship between topography and the feeling of the surface has been investigated for commercial tissues with varying degree of texture from the low textured crepe tissue to the highly textured embossed- and air-dried tissue products. A trained sensory panel at was used to grade perceived haptic ''roughness''. The technique used to characterize the topography was Digital light projection (DLP) technique, By the use of multivariate statistics, strong correlations between perceived roughness and topography were found with predictability of above 90 percent even though highly textured products were included. Characterization was made using areal ISO 25178-2 topography parameters in combination with non-contacting topography measurement. The best prediction ability was obtained when combining haptic properties with the topography parameters auto-correlation length (Sal), peak material volume (Vmp), core roughness depth (Sk) and the maximum height of the surface (Sz)

  10. A haptic sensing upgrade for the current EOD robotic fleet

    Science.gov (United States)

    Rowe, Patrick

    2014-06-01

    The past decade and a half has seen a tremendous rise in the use of mobile manipulator robotic platforms for bomb inspection and disposal, explosive ordnance disposal, and other extremely hazardous tasks in both military and civilian settings. Skilled operators are able to control these robotic vehicles in amazing ways given the very limited situational awareness obtained from a few on-board camera views. Future generations of robotic platforms will, no doubt, provide some sort of additional force or haptic sensor feedback to further enhance the operator's interaction with the robot, especially when dealing with fragile, unstable, and explosive objects. Unfortunately, the robot operators need this capability today. This paper discusses an approach to provide existing (and future) robotic mobile manipulator platforms, with which trained operators are already familiar and highly proficient, this desired haptic and force feedback capability. The goals of this technology are to be rugged, reliable, and affordable. It should also be able to be applied to a wide range of existing robots with a wide variety of manipulator/gripper sizes and styles. Finally, the presentation of the haptic information to the operator is discussed, given the fact that control devices that physically interact with the operators are not widely available and still in the research stages.

  11. Design and Calibration of a New 6 DOF Haptic Device

    Science.gov (United States)

    Qin, Huanhuan; Song, Aiguo; Liu, Yuqing; Jiang, Guohua; Zhou, Bohe

    2015-01-01

    For many applications such as tele-operational robots and interactions with virtual environments, it is better to have performance with force feedback than without. Haptic devices are force reflecting interfaces. They can also track human hand positions simultaneously. A new 6 DOF (degree-of-freedom) haptic device was designed and calibrated in this study. It mainly contains a double parallel linkage, a rhombus linkage, a rotating mechanical structure and a grasping interface. Benefited from the unique design, it is a hybrid structure device with a large workspace and high output capability. Therefore, it is capable of multi-finger interactions. Moreover, with an adjustable base, operators can change different postures without interrupting haptic tasks. To investigate the performance regarding position tracking accuracy and static output forces, we conducted experiments on a three-dimensional electric sliding platform and a digital force gauge, respectively. Displacement errors and force errors are calculated and analyzed. To identify the capability and potential of the device, four application examples were programmed. PMID:26690449

  12. Graphic and haptic simulation system for virtual laparoscopic rectum surgery.

    Science.gov (United States)

    Pan, Jun J; Chang, Jian; Yang, Xiaosong; Zhang, Jian J; Qureshi, Tahseen; Howell, Robert; Hickish, Tamas

    2011-09-01

    Medical simulators with vision and haptic feedback techniques offer a cost-effective and efficient alternative to the traditional medical trainings. They have been used to train doctors in many specialties of medicine, allowing tasks to be practised in a safe and repetitive manner. This paper describes a virtual-reality (VR) system which will help to influence surgeons' learning curves in the technically challenging field of laparoscopic surgery of the rectum. Data from MRI of the rectum and real operation videos are used to construct the virtual models. A haptic force filter based on radial basis functions is designed to offer realistic and smooth force feedback. To handle collision detection efficiently, a hybrid model is presented to compute the deformation of intestines. Finally, a real-time cutting technique based on mesh is employed to represent the incision operation. Despite numerous research efforts, fast and realistic solutions of soft tissues with large deformation, such as intestines, prove extremely challenging. This paper introduces our latest contribution to this endeavour. With this system, the user can haptically operate with the virtual rectum and simultaneously watch the soft tissue deformation. Our system has been tested by colorectal surgeons who believe that the simulated tactile and visual feedbacks are realistic. It could replace the traditional training process and effectively transfer surgical skills to novices. Copyright © 2011 John Wiley & Sons, Ltd.

  13. A Fabric-Based Approach for Wearable Haptics

    Directory of Open Access Journals (Sweden)

    Matteo Bianchi

    2016-07-01

    Full Text Available In recent years, wearable haptic systems (WHS have gained increasing attention as a novel and exciting paradigm for human–robot interaction (HRI. These systems can be worn by users, carried around, and integrated in their everyday lives, thus enabling a more natural manner to deliver tactile cues. At the same time, the design of these types of devices presents new issues: the challenge is the correct identification of design guidelines, with the two-fold goal of minimizing system encumbrance and increasing the effectiveness and naturalness of stimulus delivery. Fabrics can represent a viable solution to tackle these issues. They are specifically thought “to be worn”, and could be the key ingredient to develop wearable haptic interfaces conceived for a more natural HRI. In this paper, the author will review some examples of fabric-based WHS that can be applied to different body locations, and elicit different haptic perceptions for different application fields. Perspective and future developments of this approach will be discussed.

  14. Visual-haptic integration with pliers and tongs: signal ‘weights’ take account of changes in haptic sensitivity caused by different tools

    Directory of Open Access Journals (Sweden)

    Chie eTakahashi

    2014-02-01

    Full Text Available When we hold an object while looking at it, estimates from visual and haptic cues to size are combined in a statistically optimal fashion, whereby the ‘weight’ given to each signal reflects their relative reliabilities. This allows object properties to be estimated more precisely than would otherwise be possible. Tools such as pliers and tongs systematically perturb the mapping between object size and the hand opening. This could complicate visual-haptic integration because it may alter the reliability of the haptic signal, thereby disrupting the determination of appropriate signal weights. To investigate this we first measured the reliability of haptic size estimates made with virtual pliers-like tools (created using a stereoscopic display and force-feedback robots with different ‘gains’ between hand opening and object size. Haptic reliability in tool use was straightforwardly determined by a combination of sensitivity to changes in hand opening and the effects of tool geometry. The precise pattern of sensitivity to hand opening, which violated Weber’s law, meant that haptic reliability changed with tool gain. We then examined whether the visuo-motor system accounts for these reliability changes. We measured the weight given to visual and haptic stimuli when both were available, again with different tool gains, by measuring the perceived size of stimuli in which visual and haptic sizes were varied independently. The weight given to each sensory cue changed with tool gain in a manner that closely resembled the predictions of optimal sensory integration. The results are consistent with the idea that different tool geometries are modelled by the brain, allowing it to calculate not only the distal properties of objects felt with tools, but also the certainty with which those properties are known. These findings highlight the flexibility of human sensory integration and tool-use, and potentially provide an approach for optimising the

  15. Extrinsic and intrinsic curvatures in thermodynamic geometry

    Energy Technology Data Exchange (ETDEWEB)

    Hosseini Mansoori, Seyed Ali, E-mail: shossein@bu.edu [Department of Physics, Boston University, 590 Commonwealth Ave., Boston, MA 02215 (United States); Department of Physics, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Mirza, Behrouz, E-mail: b.mirza@cc.iut.ac.ir [Department of Physics, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Sharifian, Elham, E-mail: e.sharifian@ph.iut.ac.ir [Department of Physics, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

    2016-08-10

    We investigate the intrinsic and extrinsic curvatures of a certain hypersurface in thermodynamic geometry of a physical system and show that they contain useful thermodynamic information. For an anti-Reissner–Nordström-(A)de Sitter black hole (Phantom), the extrinsic curvature of a constant Q hypersurface has the same sign as the heat capacity around the phase transition points. The intrinsic curvature of the hypersurface can also be divergent at the critical points but has no information about the sign of the heat capacity. Our study explains the consistent relationship holding between the thermodynamic geometry of the KN-AdS black holes and those of the RN (J-zero hypersurface) and Kerr black holes (Q-zero hypersurface) ones [1]. This approach can easily be generalized to an arbitrary thermodynamic system.

  16. Extrinsic and intrinsic curvatures in thermodynamic geometry

    International Nuclear Information System (INIS)

    Hosseini Mansoori, Seyed Ali; Mirza, Behrouz; Sharifian, Elham

    2016-01-01

    We investigate the intrinsic and extrinsic curvatures of a certain hypersurface in thermodynamic geometry of a physical system and show that they contain useful thermodynamic information. For an anti-Reissner–Nordström-(A)de Sitter black hole (Phantom), the extrinsic curvature of a constant Q hypersurface has the same sign as the heat capacity around the phase transition points. The intrinsic curvature of the hypersurface can also be divergent at the critical points but has no information about the sign of the heat capacity. Our study explains the consistent relationship holding between the thermodynamic geometry of the KN-AdS black holes and those of the RN (J-zero hypersurface) and Kerr black holes (Q-zero hypersurface) ones [1]. This approach can easily be generalized to an arbitrary thermodynamic system.

  17. Substrate curvature gradient drives rapid droplet motion.

    Science.gov (United States)

    Lv, Cunjing; Chen, Chao; Chuang, Yin-Chuan; Tseng, Fan-Gang; Yin, Yajun; Grey, Francois; Zheng, Quanshui

    2014-07-11

    Making small liquid droplets move spontaneously on solid surfaces is a key challenge in lab-on-chip and heat exchanger technologies. Here, we report that a substrate curvature gradient can accelerate micro- and nanodroplets to high speeds on both hydrophilic and hydrophobic substrates. Experiments for microscale water droplets on tapered surfaces show a maximum speed of 0.42  m/s, 2 orders of magnitude higher than with a wettability gradient. We show that the total free energy and driving force exerted on a droplet are determined by the substrate curvature and substrate curvature gradient, respectively. Using molecular dynamics simulations, we predict nanoscale droplets moving spontaneously at over 100  m/s on tapered surfaces.

  18. Cosmic curvature from de Sitter equilibrium cosmology.

    Science.gov (United States)

    Albrecht, Andreas

    2011-10-07

    I show that the de Sitter equilibrium cosmology generically predicts observable levels of curvature in the Universe today. The predicted value of the curvature, Ω(k), depends only on the ratio of the density of nonrelativistic matter to cosmological constant density ρ(m)(0)/ρ(Λ) and the value of the curvature from the initial bubble that starts the inflation, Ω(k)(B). The result is independent of the scale of inflation, the shape of the potential during inflation, and many other details of the cosmology. Future cosmological measurements of ρ(m)(0)/ρ(Λ) and Ω(k) will open up a window on the very beginning of our Universe and offer an opportunity to support or falsify the de Sitter equilibrium cosmology.

  19. Radion stabilization in higher curvature warped spacetime

    Energy Technology Data Exchange (ETDEWEB)

    Das, Ashmita [Indian Institute of Technology, Department of Physics, Guwahati, Assam (India); Mukherjee, Hiya; Paul, Tanmoy; SenGupta, Soumitra [Indian Association for the Cultivation of Science, Department of Theoretical Physics, Kolkata (India)

    2018-02-15

    We consider a five dimensional AdS spacetime in presence of higher curvature term like F(R) = R + αR{sup 2} in the bulk. In this model, we examine the possibility of modulus stabilization from the scalar degrees of freedom of higher curvature gravity free of ghosts. Our result reveals that the model stabilizes itself and the mechanism of modulus stabilization can be argued from a geometric point of view. We determine the region of the parametric space for which the modulus (or radion) can to be stabilized. We also show how the mass and coupling parameters of radion field are modified due to higher curvature term leading to modifications of its phenomenological implications on the visible 3-brane. (orig.)

  20. Longitudinal surface curvature effect in magnetohydrodynamics

    International Nuclear Information System (INIS)

    Bodas, N.G.

    1975-01-01

    The two-dimensional motion of an incompressible and electrically conducting fluid past an electrically insulated body surface (having curvature) is studied for a given O(1) basic flow and magnetic field, when (i) the applied magnetic field is aligned with the velocity in the basic flow, and (ii) the applied magnetic field is within the body surface. 01 and 0(Re sup(1/2)) mean the first and second order approximations respectively in an exansion scheme in powers of Resup(-1/2), Re being the Reynolds number). The technique of matched asymptotic expansions is used to solve the problem. The governing partial differential equations to 0(Resup(-1/2)) boundary layer approximation are found to give similarity solutions for a family of surface curvature and pressure gradient distributions in case (i), and for uniform basic flow with analytic surface curvature distributions in case (ii). The equations are solved numerically. In case (i) it is seen that the effect of the magnetic field on the skin-friction- correction due to the curvature is very small. Also the magnetic field at the wall is reduced by the curvature on the convex side. In case (ii) the magnetic field significantly increases the skin-friction-correction due to the curvature. The effect of the magnetic field on the O(1) and O(Resup(-1/2)) skin friction coefficients increases with the increase of the electrical conductivity of the fluid. Also, at higher values of the magnetic pressure, moderate changes in the electrical conductivity do not influence the correction to the skin-friction significantly. (Auth.)

  1. Connections and curvatures on complex Riemannian manifolds

    International Nuclear Information System (INIS)

    Ganchev, G.; Ivanov, S.

    1991-05-01

    Characteristic connection and characteristic holomorphic sectional curvatures are introduced on a complex Riemannian manifold (not necessarily with holomorphic metric). For the class of complex Riemannian manifolds with holomorphic characteristic connection a classification of the manifolds with (pointwise) constant holomorphic characteristic curvature is given. It is shown that the conformal geometry of complex analytic Riemannian manifolds can be naturally developed on the class of locally conformal holomorphic Riemannian manifolds. Complex Riemannian manifolds locally conformal to the complex Euclidean space are characterized with zero conformal fundamental tensor and zero conformal characteristic tensor. (author). 12 refs

  2. Identification of virtual grounds using virtual reality haptic shoes and sound synthesis

    DEFF Research Database (Denmark)

    Serafin, Stefania; Turchet, Luca; Nordahl, Rolf

    2010-01-01

    We describe a system which simulates in real-time the auditory and haptic sensation of walking on different surfaces. The system is based on physical models, that drive both the haptic and audio synthesizers, and a pair of shoes enhanced with sensors and actuators. In a discrimination experiment,...

  3. Haptic Cues Used for Outdoor Wayfinding by Individuals with Visual Impairments

    Science.gov (United States)

    Koutsoklenis, Athanasios; Papadopoulos, Konstantinos

    2014-01-01

    Introduction: The study presented here examines which haptic cues individuals with visual impairments use more frequently and determines which of these cues are deemed by these individuals to be the most important for way-finding in urban environments. It also investigates the ways in which these haptic cues are used by individuals with visual…

  4. Haptic shared control improves hot cell remote handling despite controller inaccuracies

    NARCIS (Netherlands)

    van Oosterhout, J.; Abbink, D. A.; Koning, J. F.; Boessenkool, H.; Wildenbeest, J. G. W.; Heemskerk, C. J. M.

    2013-01-01

    A promising solution to improve task performance in ITER hot cell remote handling is the use of haptic shared control. Haptic shared control can assist the human operator along a safe and optimal path with continuous guiding forces from an intelligent autonomous controller. Previous research tested

  5. Telerobotic Haptic Exploration in Art Galleries and Museums for Individuals with Visual Impairments.

    Science.gov (United States)

    Park, Chung Hyuk; Ryu, Eun-Seok; Howard, Ayanna M

    2015-01-01

    This paper presents a haptic telepresence system that enables visually impaired users to explore locations with rich visual observation such as art galleries and museums by using a telepresence robot, a RGB-D sensor (color and depth camera), and a haptic interface. The recent improvement on RGB-D sensors has enabled real-time access to 3D spatial information in the form of point clouds. However, the real-time representation of this data in the form of tangible haptic experience has not been challenged enough, especially in the case of telepresence for individuals with visual impairments. Thus, the proposed system addresses the real-time haptic exploration of remote 3D information through video encoding and real-time 3D haptic rendering of the remote real-world environment. This paper investigates two scenarios in haptic telepresence, i.e., mobile navigation and object exploration in a remote environment. Participants with and without visual impairments participated in our experiments based on the two scenarios, and the system performance was validated. In conclusion, the proposed framework provides a new methodology of haptic telepresence for individuals with visual impairments by providing an enhanced interactive experience where they can remotely access public places (art galleries and museums) with the aid of haptic modality and robotic telepresence.

  6. Differential effects of non-informative vision and visual interference on haptic spatial processing

    NARCIS (Netherlands)

    Volcic, Robert; Van Rheede, Joram J.; Postma, Albert; Kappers, Astrid M L

    The primary purpose of this study was to examine the effects of non-informative vision and visual interference upon haptic spatial processing, which supposedly derives from an interaction between an allocentric and egocentric reference frame. To this end, a haptic parallelity task served as baseline

  7. Feeling objects in Virtual Environments: Presence and Pseudo-Haptics in a Bowling Game

    DEFF Research Database (Denmark)

    Daniliauskaite, Kristina; Magnusdottir, Agusta; Bjørkå, Henrik Birke

    2007-01-01

    , by relying on visual cues, taking therefore advantage of sensory substitution (no haptic feedback device is actually present). The interdependency between presence and a pseudo-haptic feedback is investigated by building avirtual bowling game. Results indicate that there is a significant correlation between...

  8. Investigating Students' Ideas About Buoyancy and the Influence of Haptic Feedback

    Science.gov (United States)

    Minogue, James; Borland, David

    2016-04-01

    While haptics (simulated touch) represents a potential breakthrough technology for science teaching and learning, there is relatively little research into its differential impact in the context of teaching and learning. This paper describes the testing of a haptically enhanced simulation (HES) for learning about buoyancy. Despite a lifetime of everyday experiences, a scientifically sound explanation of buoyancy remains difficult to construct for many. It requires the integration of domain-specific knowledge regarding density, fluid, force, gravity, mass, weight, and buoyancy. Prior studies suggest that novices often focus on only one dimension of the sinking and floating phenomenon. Our HES was designed to promote the integration of the subconcepts of density and buoyant forces and stresses the relationship between the object itself and the surrounding fluid. The study employed a randomized pretest-posttest control group research design and a suite of measures including an open-ended prompt and objective content questions to provide insights into the influence of haptic feedback on undergraduate students' thinking about buoyancy. A convenience sample (n = 40) was drawn from a university's population of undergraduate elementary education majors. Two groups were formed from haptic feedback (n = 22) and no haptic feedback (n = 18). Through content analysis, discernible differences were seen in the posttest explanations sinking and floating across treatment groups. Learners that experienced the haptic feedback made more frequent use of "haptically grounded" terms (e.g., mass, gravity, buoyant force, pushing), leading us to begin to build a local theory of language-mediated haptic cognition.

  9. Immediate Memory for Haptically-Examined Braille Symbols by Blind and Sighted Subjects.

    Science.gov (United States)

    Newman, Slater E.; And Others

    The paper reports on two experiments in Braille learning which compared blind and sighted subjects on the immediate recall of haptically-examined Braille symbols. In the first study, sighted subjects (N=64) haptically examined each of a set of Braille symbols with their preferred or nonpreferred hand and immediately recalled the symbol by drawing…

  10. A new visual feedback-based magnetorheological haptic master for robot-assisted minimally invasive surgery

    Science.gov (United States)

    Choi, Seung-Hyun; Kim, Soomin; Kim, Pyunghwa; Park, Jinhyuk; Choi, Seung-Bok

    2015-06-01

    In this study, we developed a novel four-degrees-of-freedom haptic master using controllable magnetorheological (MR) fluid. We also integrated the haptic master with a vision device with image processing for robot-assisted minimally invasive surgery (RMIS). The proposed master can be used in RMIS as a haptic interface to provide the surgeon with a sense of touch by using both kinetic and kinesthetic information. The slave robot, which is manipulated with a proportional-integrative-derivative controller, uses a force sensor to obtain the desired forces from tissue contact, and these desired repulsive forces are then embodied through the MR haptic master. To verify the effectiveness of the haptic master, the desired force and actual force are compared in the time domain. In addition, a visual feedback system is implemented in the RMIS experiment to distinguish between the tumor and organ more clearly and provide better visibility to the operator. The hue-saturation-value color space is adopted for the image processing since it is often more intuitive than other color spaces. The image processing and haptic feedback are realized on surgery performance. In this work, tumor-cutting experiments are conducted under four different operating conditions: haptic feedback on, haptic feedback off, image processing on, and image processing off. The experimental realization shows that the performance index, which is a function of pixels, is different in the four operating conditions.

  11. A new visual feedback-based magnetorheological haptic master for robot-assisted minimally invasive surgery

    International Nuclear Information System (INIS)

    Choi, Seung-Hyun; Kim, Soomin; Kim, Pyunghwa; Park, Jinhyuk; Choi, Seung-Bok

    2015-01-01

    In this study, we developed a novel four-degrees-of-freedom haptic master using controllable magnetorheological (MR) fluid. We also integrated the haptic master with a vision device with image processing for robot-assisted minimally invasive surgery (RMIS). The proposed master can be used in RMIS as a haptic interface to provide the surgeon with a sense of touch by using both kinetic and kinesthetic information. The slave robot, which is manipulated with a proportional-integrative-derivative controller, uses a force sensor to obtain the desired forces from tissue contact, and these desired repulsive forces are then embodied through the MR haptic master. To verify the effectiveness of the haptic master, the desired force and actual force are compared in the time domain. In addition, a visual feedback system is implemented in the RMIS experiment to distinguish between the tumor and organ more clearly and provide better visibility to the operator. The hue-saturation-value color space is adopted for the image processing since it is often more intuitive than other color spaces. The image processing and haptic feedback are realized on surgery performance. In this work, tumor-cutting experiments are conducted under four different operating conditions: haptic feedback on, haptic feedback off, image processing on, and image processing off. The experimental realization shows that the performance index, which is a function of pixels, is different in the four operating conditions. (paper)

  12. Obstacle Crossing Differences Between Blind and Blindfolded Subjects After Haptic Exploration

    NARCIS (Netherlands)

    Forner-Cordero, A.; Garcia, V.D.; Rodrigues, S.T.; Duysens, J.

    2016-01-01

    Little is known about the ability of blind people to cross obstacles after they have explored haptically their size and position. Long-term absence of vision may affect spatial cognition in the blind while their extensive experience with the use of haptic information for guidance may lead to

  13. Zero curvature conditions and conformal covariance

    International Nuclear Information System (INIS)

    Akemann, G.; Grimm, R.

    1992-05-01

    Two-dimensional zero curvature conditions were investigated in detail, with special emphasis on conformal properties, and the appearance of covariant higher order differential operators constructed in terms of a projective connection was elucidated. The analysis is based on the Kostant decomposition of simple Lie algebras in terms of representations with respect to their 'principal' SL(2) subalgebra. (author) 27 refs

  14. Norm of the Riemannian Curvature Tensor

    Indian Academy of Sciences (India)

    We consider the Riemannian functional R p ( g ) = ∫ M | R ( g ) | p d v g defined on the space of Riemannian metrics with unit volume on a closed smooth manifold where R ( g ) and d v g denote the corresponding Riemannian curvature tensor and volume form and p ∈ ( 0 , ∞ ) . First we prove that the Riemannian metrics ...

  15. Constraining inverse curvature gravity with supernovae

    Energy Technology Data Exchange (ETDEWEB)

    Mena, Olga; Santiago, Jose; /Fermilab; Weller, Jochen; /University Coll., London /Fermilab

    2005-10-01

    We show that the current accelerated expansion of the Universe can be explained without resorting to dark energy. Models of generalized modified gravity, with inverse powers of the curvature can have late time accelerating attractors without conflicting with solar system experiments. We have solved the Friedman equations for the full dynamical range of the evolution of the Universe. This allows us to perform a detailed analysis of Supernovae data in the context of such models that results in an excellent fit. Hence, inverse curvature gravity models represent an example of phenomenologically viable models in which the current acceleration of the Universe is driven by curvature instead of dark energy. If we further include constraints on the current expansion rate of the Universe from the Hubble Space Telescope and on the age of the Universe from globular clusters, we obtain that the matter content of the Universe is 0.07 {le} {omega}{sub m} {le} 0.21 (95% Confidence). Hence the inverse curvature gravity models considered can not explain the dynamics of the Universe just with a baryonic matter component.

  16. On Mass, Spacetime Curvature, and Gravity

    Science.gov (United States)

    Janis, Allen I.

    2018-01-01

    The frequently used analogy of a massive ball distorting an elastic sheet, which is used to illustrate why mass causes spacetime curvature and gravitational attraction, is criticized in this article. A different analogy that draws on the students' previous knowledge of spacetime diagrams in special relativity is suggested.

  17. Curvature tensor copies in affine geometry

    International Nuclear Information System (INIS)

    Srivastava, P.P.

    1981-01-01

    The sets of space-time and spin-connections which give rise to the same curvature tensor are constructed. The corresponding geometries are compared. Results are illustrated by an explicit calculation and comment on the copies in Einstein-Cartan and Weyl-Cartan geometries. (Author) [pt

  18. Gaussian curvature on hyperelliptic Riemann surfaces

    Indian Academy of Sciences (India)

    Indian Acad. Sci. (Math. Sci.) Vol. 124, No. 2, May 2014, pp. 155–167. c Indian Academy of Sciences. Gaussian curvature on hyperelliptic Riemann surfaces. ABEL CASTORENA. Centro de Ciencias Matemáticas (Universidad Nacional Autónoma de México,. Campus Morelia) Apdo. Postal 61-3 Xangari, C.P. 58089 Morelia,.

  19. Resolving curvature singularities in holomorphic gravity

    NARCIS (Netherlands)

    Mantz, C.L.M.; Prokopec, T.

    2011-01-01

    We formulate a holomorphic theory of gravity and study how the holomorphy symmetry alters the two most important singular solutions of general relativity: black holes and cosmology. We show that typical observers (freely) falling into a holomorphic black hole do not encounter a curvature

  20. Curvature driven instabilities in toroidal plasmas

    International Nuclear Information System (INIS)

    Andersson, P.

    1986-11-01

    The electromagnetic ballooning mode, the curvature driven trapped electron mode and the toroidally induced ion temperature gradient mode have been studies. Eigenvalue equations have been derived and solved both numerically and analytically. For electromagnetic ballooning modes the effects of convective damping, finite Larmor radius, higher order curvature terms, and temperature gradients have been investigated. A fully toroidal fluid ion model has been developed. It is shown that a necessary and sufficient condition for an instability below the MHD limit is the presence of an ion temperature gradient. Analytical dispersion relations giving results in good agreement with numerical solutions are also presented. The curvature driven trapped electron modes are found to be unstable for virtually all parameters with growth rates of the order of the diamagnetic drift frequency. Studies have been made, using both a gyrokinetic ion description and the fully toroidal ion model. Both analytical and numerical results are presented and are found to be in good agreement. The toroidally induced ion temperature gradients modes are found to have a behavior similar to that of the curvature driven trapped electron modes and can in the electrostatic limit be described by a simple quadratic dispersion equation. (author)

  1. Random paths with curvature dependent action

    International Nuclear Information System (INIS)

    Ambjoern, J.; Durhuus, B.

    1986-11-01

    We study discretized random paths with a curvature dependent action. The scaling limits of the corresponding statistical mechanical models can be constructed explicitly and are either usual Brownian motion or a theory where the correlations of tangents are nonzero and described by diffusion on the unit sphere. In the latter case the two point function has an anomalous dimension η = 1. (orig.)

  2. Vertical illusory self-motion through haptic stimulation of the feet

    DEFF Research Database (Denmark)

    Nordahl, Rolf; Nilsson, Niels Christian; Turchet, Luca

    2012-01-01

    Circular and linear self-motion illusions induced through visual and auditory stimuli have been studied rather extensively. While the ability of haptic stimuli to augment such illusions has been investigated, the self-motion illusions which primarily are induced by stimulation of the haptic...... to generate the haptic feedback while the final condition included no haptic feedback. Analysis of self-reports were used to assess the participants' experience of illusory self-motion. The results indicate that such illusions are indeed possible. Significant differences were found between the condition...... modality remain relatively unexplored. In this paper, we present an experiment performed with the intention of investigating whether it is possible to use haptic stimulation of the main supporting areas of the feet to induce vertical illusory self-motion on behalf of unrestrained participants during...

  3. Haptic Feedback in Motor Hand Virtual Therapy Increases Precision and Generates Less Mental Workload

    Directory of Open Access Journals (Sweden)

    Cristina Ramírez-Fernández

    2015-10-01

    Full Text Available In this work we show that haptic feedback in upper limb motor therapy improves performance and generates a lower mental workload. To demonstrate this, two groups of participants (healthy adults and elders with hand motor problems used a low-cost haptic device (Novint Falcon and a non-robotic device (Leap Motion Controller. Participants conducted the same rehabilitation task by using a non-immersive virtual environment. Results show significant differences for all participants regarding precision on the use of the haptic feedback device. Additionally, participants in the older adult group demonstrated a lower mental workload while using the haptic device (Novint Falcon. Finally, qualitative results show that participants preferred to conduct their therapy exercises by using the haptic device, as they found it more useful, easier to use and easier to learn

  4. Haptic device development based on electro static force of cellulose electro active paper

    Science.gov (United States)

    Yun, Gyu-young; Kim, Sang-Youn; Jang, Sang-Dong; Kim, Dong-Gu; Kim, Jaehwan

    2011-04-01

    Haptic is one of well-considered device which is suitable for demanding virtual reality applications such as medical equipment, mobile devices, the online marketing and so on. Nowadays, many of concepts for haptic devices have been suggested to meet the demand of industries. Cellulose has received much attention as an emerging smart material, named as electro-active paper (EAPap). The EAPap is attractive for mobile haptic devices due to its unique characteristics in terms of low actuation power, suitability for thin devices and transparency. In this paper, we suggest a new concept of haptic actuator with the use of cellulose EAPap. Its performance is evaluated depending on various actuation conditions. As a result, cellulose electrostatic force actuator shows a large output displacement and fast response, which is suitable for mobile haptic devices.

  5. KinoHaptics: An Automated, Wearable, Haptic Assisted, Physio-therapeutic System for Post-surgery Rehabilitation and Self-care.

    Science.gov (United States)

    Rajanna, Vijay; Vo, Patrick; Barth, Jerry; Mjelde, Matthew; Grey, Trevor; Oduola, Cassandra; Hammond, Tracy

    2016-03-01

    A carefully planned, structured, and supervised physiotherapy program, following a surgery, is crucial for the successful diagnosis of physical injuries. Nearly 50 % of the surgeries fail due to unsupervised, and erroneous physiotherapy. The demand for a physiotherapist for an extended period is expensive to afford, and sometimes inaccessible. Researchers have tried to leverage the advancements in wearable sensors and motion tracking by building affordable, automated, physio-therapeutic systems that direct a physiotherapy session by providing audio-visual feedback on patient's performance. There are many aspects of automated physiotherapy program which are yet to be addressed by the existing systems: a wide classification of patients' physiological conditions to be diagnosed, multiple demographics of the patients (blind, deaf, etc.), and the need to pursue patients to adopt the system for an extended period for self-care. In our research, we have tried to address these aspects by building a health behavior change support system called KinoHaptics, for post-surgery rehabilitation. KinoHaptics is an automated, wearable, haptic assisted, physio-therapeutic system that can be used by a wide variety of demographics and for various physiological conditions of the patients. The system provides rich and accurate vibro-haptic feedback that can be felt by the user, irrespective of the physiological limitations. KinoHaptics is built to ensure that no injuries are induced during the rehabilitation period. The persuasive nature of the system allows for personal goal-setting, progress tracking, and most importantly life-style compatibility. The system was evaluated under laboratory conditions, involving 14 users. Results show that KinoHaptics is highly convenient to use, and the vibro-haptic feedback is intuitive, accurate, and has shown to prevent accidental injuries. Also, results show that KinoHaptics is persuasive in nature as it supports behavior change and habit building

  6. Awareness Becomes Necessary Between Adaptive Pattern Coding of Open and Closed Curvatures

    Science.gov (United States)

    Sweeny, Timothy D.; Grabowecky, Marcia; Suzuki, Satoru

    2012-01-01

    Visual pattern processing becomes increasingly complex along the ventral pathway, from the low-level coding of local orientation in the primary visual cortex to the high-level coding of face identity in temporal visual areas. Previous research using pattern aftereffects as a psychophysical tool to measure activation of adaptive feature coding has suggested that awareness is relatively unimportant for the coding of orientation, but awareness is crucial for the coding of face identity. We investigated where along the ventral visual pathway awareness becomes crucial for pattern coding. Monoptic masking, which interferes with neural spiking activity in low-level processing while preserving awareness of the adaptor, eliminated open-curvature aftereffects but preserved closed-curvature aftereffects. In contrast, dichoptic masking, which spares spiking activity in low-level processing while wiping out awareness, preserved open-curvature aftereffects but eliminated closed-curvature aftereffects. This double dissociation suggests that adaptive coding of open and closed curvatures straddles the divide between weakly and strongly awareness-dependent pattern coding. PMID:21690314

  7. Sensitive zone parameters and curvature radius evaluation for polymer optical fiber curvature sensors

    Science.gov (United States)

    Leal-Junior, Arnaldo G.; Frizera, Anselmo; José Pontes, Maria

    2018-03-01

    Polymer optical fibers (POFs) are suitable for applications such as curvature sensors, strain, temperature, liquid level, among others. However, for enhancing sensitivity, many polymer optical fiber curvature sensors based on intensity variation require a lateral section. Lateral section length, depth, and surface roughness have great influence on the sensor sensitivity, hysteresis, and linearity. Moreover, the sensor curvature radius increase the stress on the fiber, which leads on variation of the sensor behavior. This paper presents the analysis relating the curvature radius and lateral section length, depth and surface roughness with the sensor sensitivity, hysteresis and linearity for a POF curvature sensor. Results show a strong correlation between the decision parameters behavior and the performance for sensor applications based on intensity variation. Furthermore, there is a trade-off among the sensitive zone length, depth, surface roughness, and curvature radius with the sensor desired performance parameters, which are minimum hysteresis, maximum sensitivity, and maximum linearity. The optimization of these parameters is applied to obtain a sensor with sensitivity of 20.9 mV/°, linearity of 0.9992 and hysteresis below 1%, which represent a better performance of the sensor when compared with the sensor without the optimization.

  8. A curvature theory for discrete surfaces based on mesh parallelity

    KAUST Repository

    Bobenko, Alexander Ivanovich; Pottmann, Helmut; Wallner, Johannes

    2009-01-01

    We consider a general theory of curvatures of discrete surfaces equipped with edgewise parallel Gauss images, and where mean and Gaussian curvatures of faces are derived from the faces' areas and mixed areas. Remarkably these notions are capable

  9. The "Haptic Finger"- a new device for monitoring skin condition.

    Science.gov (United States)

    Tanaka, Mami; Lévêque, Jean Luc; Tagami, Hachiro; Kikuchi, Katsuko; Chonan, Seifi

    2003-05-01

    Touching the skin is of great importance for the Clinician for assessing roughness, softness, firmness, etc. This type of clinical assessment is very subjective and therefore non-reproducible from one Clinician to another one or even from time to time for the same Clinician. In order to objectively monitor skin texture, we developed a new sensor, placed directly on the Clinician's finger, which generate some electric signal when slid over the skin surface. The base of this Haptic Finger sensor is a thin stainless steel plate on which sponge rubber, PVDF foil, acetate film and gauze are layered. The signal generated by the sensor was filtered and digitally stored before processing. In a first in vitro experiment, the sensor was moved over different skin models (sponge rubber covered by silicon rubber) of varying hardness and roughness. These experiments allowed the definition of two parameters characterizing textures. The first parameter is variance of the signal processed using wavelet analysis, representing an index of roughness. The second parameter is dispersion of the power spectrum density in the frequency domain, corresponding to hardness. To validate these parameters, the Haptic Finger was used to scan skin surfaces of 30 people, 14 of whom displayed a skin disorder: xerosis (n = 5), atopic dermatitis (n = 7), and psoriasis (n = 2). The results obtained by means of the sensor were compared with subjective, clinical evaluations by a Clinician who scored both roughness and hardness of the skin. Good agreement was observed between clinical assessment of the skin and the two parameters generated using the Haptic Finger. Use of this sensor could prove extremely valuable in cosmetic research where skin surface texture (in terms of tactile properties) is difficult to measure.

  10. Converting entropy to curvature perturbations after a cosmic bounce

    Energy Technology Data Exchange (ETDEWEB)

    Fertig, Angelika; Lehners, Jean-Luc; Mallwitz, Enno; Wilson-Ewing, Edward [Max Planck Institute for Gravitational Physics, Albert Einstein Institute,14476 Potsdam-Golm (Germany)

    2016-10-04

    We study two-field bouncing cosmologies in which primordial perturbations are created in either an ekpyrotic or a matter-dominated contraction phase. We use a non-singular ghost condensate bounce model to follow the perturbations through the bounce into the expanding phase of the universe. In contrast to the adiabatic perturbations, which on large scales are conserved across the bounce, entropy perturbations can grow significantly during the bounce phase. If they are converted into adiabatic/curvature perturbations after the bounce, they typically form the dominant contribution to the observed temperature fluctuations in the microwave background, which can have several beneficial implications. For ekpyrotic models, this mechanism loosens the constraints on the amplitude of the ekpyrotic potential while naturally suppressing the intrinsic amount of non-Gaussianity. For matter bounce models, the mechanism amplifies the scalar perturbations compared to the associated primordial gravitational waves.

  11. Archaeologies of touch interfacing with haptics from electricity to computing

    CERN Document Server

    Parisi, David

    2018-01-01

    David Parisi offers the first full history of new computing technologies known as haptic interfaces--which use electricity, vibration, and force feedback to stimulate the sense of touch--showing how the efforts of scientists and engineers over the past 300 years have gradually remade and redefined our sense of touch. Archaeologies of Touch offers a timely and provocative engagement with the long history of touch technology that helps us confront and question the power relations underpinning the project of giving touch its own set of technical media.

  12. New geometric data structures for collision detection and haptics

    CERN Document Server

    Weller, René

    2013-01-01

    Starting with novel algorithms for optimally updating bounding volume hierarchies of objects undergoing arbitrary deformations, the author presents a new data structure that allows, for the first time, the computation of the penetration volume. The penetration volume is related to the water displacement of the overlapping region, and thus corresponds to a physically motivated and continuous force. The practicability of the approaches used is shown by realizing new applications in the field of robotics and haptics, including a user study that evaluates the influence of the degrees of freedom in

  13. Collineations of the curvature tensor in general relativity

    Indian Academy of Sciences (India)

    Curvature collineations for the curvature tensor, constructed from a fundamental Bianchi Type-V metric, are studied. We are concerned with a symmetry property of space-time which is called curvature collineation, and we briefly discuss the physical and kinematical properties of the models.

  14. Translating solitons to symplectic and Lagrangian mean curvature flows

    International Nuclear Information System (INIS)

    Han Xiaoli; Li Jiayu

    2007-05-01

    In this paper, we construct finite blow-up examples for symplectic mean curvature flows and we study symplectic translating solitons. We prove that there is no translating solitons with vertical bar α vertical bar ≤ α 0 to the symplectic mean curvature flow or to the almost calibrated Lagrangian mean curvature flow for some α 0 . (author)

  15. Weyl curvature tensor in static spherical sources

    International Nuclear Information System (INIS)

    Ponce de Leon, J.

    1988-01-01

    The role of the Weyl curvature tensor in static sources of the Schwarzschild field is studied. It is shown that in general the contribution from the Weyl curvature tensor (the ''purely gravitational field energy'') to the mass-energy inside the body may be positive, negative, or zero. It is proved that a positive (negative) contribution from the Weyl tensor tends to increase (decrease) the effective gravitational mass, the red-shift (from a point in the sphere to infinity), as well as the gravitational force which acts on a constituent matter element of a body. It is also proved that the contribution from the Weyl tensor always is negative in sources with surface gravitational potential larger than (4/9. It is pointed out that large negative contributions from the Weyl tensor could give rise to the phenomenon of gravitational repulsion. A simple example which illustrates the results is discussed

  16. Discrete Curvatures and Discrete Minimal Surfaces

    KAUST Repository

    Sun, Xiang

    2012-06-01

    This thesis presents an overview of some approaches to compute Gaussian and mean curvature on discrete surfaces and discusses discrete minimal surfaces. The variety of applications of differential geometry in visualization and shape design leads to great interest in studying discrete surfaces. With the rich smooth surface theory in hand, one would hope that this elegant theory can still be applied to the discrete counter part. Such a generalization, however, is not always successful. While discrete surfaces have the advantage of being finite dimensional, thus easier to treat, their geometric properties such as curvatures are not well defined in the classical sense. Furthermore, the powerful calculus tool can hardly be applied. The methods in this thesis, including angular defect formula, cotangent formula, parallel meshes, relative geometry etc. are approaches based on offset meshes or generalized offset meshes. As an important application, we discuss discrete minimal surfaces and discrete Koenigs meshes.

  17. On a curvature-statistics theorem

    International Nuclear Information System (INIS)

    Calixto, M; Aldaya, V

    2008-01-01

    The spin-statistics theorem in quantum field theory relates the spin of a particle to the statistics obeyed by that particle. Here we investigate an interesting correspondence or connection between curvature (κ = ±1) and quantum statistics (Fermi-Dirac and Bose-Einstein, respectively). The interrelation between both concepts is established through vacuum coherent configurations of zero modes in quantum field theory on the compact O(3) and noncompact O(2; 1) (spatial) isometry subgroups of de Sitter and Anti de Sitter spaces, respectively. The high frequency limit, is retrieved as a (zero curvature) group contraction to the Newton-Hooke (harmonic oscillator) group. We also make some comments on the physical significance of the vacuum energy density and the cosmological constant problem.

  18. On a curvature-statistics theorem

    Energy Technology Data Exchange (ETDEWEB)

    Calixto, M [Departamento de Matematica Aplicada y Estadistica, Universidad Politecnica de Cartagena, Paseo Alfonso XIII 56, 30203 Cartagena (Spain); Aldaya, V [Instituto de Astrofisica de Andalucia, Apartado Postal 3004, 18080 Granada (Spain)], E-mail: Manuel.Calixto@upct.es

    2008-08-15

    The spin-statistics theorem in quantum field theory relates the spin of a particle to the statistics obeyed by that particle. Here we investigate an interesting correspondence or connection between curvature ({kappa} = {+-}1) and quantum statistics (Fermi-Dirac and Bose-Einstein, respectively). The interrelation between both concepts is established through vacuum coherent configurations of zero modes in quantum field theory on the compact O(3) and noncompact O(2; 1) (spatial) isometry subgroups of de Sitter and Anti de Sitter spaces, respectively. The high frequency limit, is retrieved as a (zero curvature) group contraction to the Newton-Hooke (harmonic oscillator) group. We also make some comments on the physical significance of the vacuum energy density and the cosmological constant problem.

  19. Cosmological signatures of anisotropic spatial curvature

    International Nuclear Information System (INIS)

    Pereira, Thiago S.; Marugán, Guillermo A. Mena; Carneiro, Saulo

    2015-01-01

    If one is willing to give up the cherished hypothesis of spatial isotropy, many interesting cosmological models can be developed beyond the simple anisotropically expanding scenarios. One interesting possibility is presented by shear-free models in which the anisotropy emerges at the level of the curvature of the homogeneous spatial sections, whereas the expansion is dictated by a single scale factor. We show that such models represent viable alternatives to describe the large-scale structure of the inflationary universe, leading to a kinematically equivalent Sachs-Wolfe effect. Through the definition of a complete set of spatial eigenfunctions we compute the two-point correlation function of scalar perturbations in these models. In addition, we show how such scenarios would modify the spectrum of the CMB assuming that the observations take place in a small patch of a universe with anisotropic curvature

  20. Cosmological signatures of anisotropic spatial curvature

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Thiago S. [Departamento de Física, Universidade Estadual de Londrina, 86057-970, Londrina – PR (Brazil); Marugán, Guillermo A. Mena [Instituto de Estructura de la Materia, IEM-CSIC, Serrano 121, 28006, Madrid (Spain); Carneiro, Saulo, E-mail: tspereira@uel.br, E-mail: mena@iem.cfmac.csic.es, E-mail: saulo.carneiro@pq.cnpq.br [Instituto de Física, Universidade Federal da Bahia, 40210-340, Salvador – BA (Brazil)

    2015-07-01

    If one is willing to give up the cherished hypothesis of spatial isotropy, many interesting cosmological models can be developed beyond the simple anisotropically expanding scenarios. One interesting possibility is presented by shear-free models in which the anisotropy emerges at the level of the curvature of the homogeneous spatial sections, whereas the expansion is dictated by a single scale factor. We show that such models represent viable alternatives to describe the large-scale structure of the inflationary universe, leading to a kinematically equivalent Sachs-Wolfe effect. Through the definition of a complete set of spatial eigenfunctions we compute the two-point correlation function of scalar perturbations in these models. In addition, we show how such scenarios would modify the spectrum of the CMB assuming that the observations take place in a small patch of a universe with anisotropic curvature.

  1. The Riemann-Lovelock curvature tensor

    International Nuclear Information System (INIS)

    Kastor, David

    2012-01-01

    In order to study the properties of Lovelock gravity theories in low dimensions, we define the kth-order Riemann-Lovelock tensor as a certain quantity having a total 4k-indices, which is kth order in the Riemann curvature tensor and shares its basic algebraic and differential properties. We show that the kth-order Riemann-Lovelock tensor is determined by its traces in dimensions 2k ≤ D < 4k. In D = 2k + 1 this identity implies that all solutions of pure kth-order Lovelock gravity are 'Riemann-Lovelock' flat. It is verified that the static, spherically symmetric solutions of these theories, which are missing solid angle spacetimes, indeed satisfy this flatness property. This generalizes results from Einstein gravity in D = 3, which corresponds to the k = 1 case. We speculate about some possible further consequences of Riemann-Lovelock curvature. (paper)

  2. Harmonic curvatures and generalized helices in En

    International Nuclear Information System (INIS)

    Camci, Cetin; Ilarslan, Kazim; Kula, Levent; Hacisalihoglu, H. Hilmi

    2009-01-01

    In n-dimensional Euclidean space E n , harmonic curvatures of a non-degenerate curve defined by Ozdamar and Hacisalihoglu [Ozdamar E, Hacisalihoglu HH. A characterization of Inclined curves in Euclidean n-space. Comm Fac Sci Univ Ankara, Ser A1 1975;24:15-23]. In this paper, we give some characterizations for a non-degenerate curve α to be a generalized helix by using its harmonic curvatures. Also we define the generalized Darboux vector D of a non-degenerate curve α in n-dimensional Euclidean space E n and we show that the generalized Darboux vector D lies in the kernel of Frenet matrix M(s) if and only if the curve α is a generalized helix in the sense of Hayden.

  3. Contrast Materials

    Science.gov (United States)

    ... is mixed with water before administration liquid paste tablet When iodine-based and barium-sulfate contrast materials ... for patients with kidney failure or allergies to MRI and/or computed tomography (CT) contrast material. Microbubble ...

  4. Gravitational curvature an introduction to Einstein's theory

    CERN Document Server

    Frankel, Theodore Thomas

    1979-01-01

    This classic text and reference monograph applies modern differential geometry to general relativity. A brief mathematical introduction to gravitational curvature, it emphasizes the subject's geometric essence, replacing the often-tedious analytical computations with geometric arguments. Clearly presented and physically motivated derivations express the deflection of light, Schwarzchild's exterior and interior solutions, and the Oppenheimer-Volkoff equations. A perfect choice for advanced students of mathematics, this volume will also appeal to mathematicians interested in physics. It stresses

  5. Curvature controlled wetting in two dimensions

    DEFF Research Database (Denmark)

    Gil, Tamir; Mikheev, Lev V.

    1995-01-01

    . As the radius of the substrate r0→∞, the leading effect of the curvature is adding the Laplace pressure ΠL∝r0-1 to the pressure balance in the film. At temperatures and pressures under which the wetting is complete in planar geometry, Laplace pressure suppresses divergence of the mean thickness of the wetting...... term reduces the thickness by the amount proportional to r0-1/3...

  6. The Riemann-Lovelock Curvature Tensor

    OpenAIRE

    Kastor, David

    2012-01-01

    In order to study the properties of Lovelock gravity theories in low dimensions, we define the kth-order Riemann-Lovelock tensor as a certain quantity having a total 4k-indices, which is kth-order in the Riemann curvature tensor and shares its basic algebraic and differential properties. We show that the kth-order Riemann-Lovelock tensor is determined by its traces in dimensions 2k \\le D

  7. Driver assistance system for passive multi-trailer vehicles with haptic steering limitations on the leading unit.

    Science.gov (United States)

    Morales, Jesús; Mandow, Anthony; Martínez, Jorge L; Reina, Antonio J; García-Cerezo, Alfonso

    2013-04-03

    Driving vehicles with one or more passive trailers has difficulties in both forward and backward motion due to inter-unit collisions, jackknife, and lack of visibility. Consequently, advanced driver assistance systems (ADAS) for multi-trailer combinations can be beneficial to accident avoidance as well as to driver comfort. The ADAS proposed in this paper aims to prevent unsafe steering commands by means of a haptic handwheel. Furthermore, when driving in reverse, the steering-wheel and pedals can be used as if the vehicle was driven from the back of the last trailer with visual aid from a rear-view camera. This solution, which can be implemented in drive-by-wire vehicles with hitch angle sensors, profits from two methods previously developed by the authors: safe steering by applying a curvature limitation to the leading unit, and a virtual tractor concept for backward motion that includes the complex case of set-point propagation through on-axle hitches. The paper addresses system requirements and provides implementation details to tele-operate two different off- and on-axle combinations of a tracked mobile robot pulling and pushing two dissimilar trailers.

  8. Driver Assistance System for Passive Multi-Trailer Vehicles with Haptic Steering Limitations on the Leading Unit

    Directory of Open Access Journals (Sweden)

    Antonio J. Reina

    2013-04-01

    Full Text Available Driving vehicles with one or more passive trailers has difficulties in both forward and backward motion due to inter-unit collisions, jackknife, and lack of visibility. Consequently, advanced driver assistance systems (ADAS for multi-trailer combinations can be beneficial to accident avoidance as well as to driver comfort. The ADAS proposed in this paper aims to prevent unsafe steering commands by means of a haptic handwheel. Furthermore, when driving in reverse, the steering-wheel and pedals can be used as if the vehicle was driven from the back of the last trailer with visual aid from a rear-view camera. This solution, which can be implemented in drive-by-wire vehicles with hitch angle sensors, profits from two methods previously developed by the authors: safe steering by applying a curvature limitation to the leading unit, and a virtual tractor concept for backward motion that includes the complex case of set-point propagation through on-axle hitches. The paper addresses system requirements and provides implementation details to tele-operate two different off- and on-axle combinations of a tracked mobile robot pulling and pushing two dissimilar trailers.

  9. A “virtually minimal” visuo-haptic training of attention in severe traumatic brain injury

    Science.gov (United States)

    2013-01-01

    Background Although common during the early stages of recovery from severe traumatic brain injury (TBI), attention deficits have been scarcely investigated. Encouraging evidence suggests beneficial effects of attention training in more chronic and higher functioning patients. Interactive technology may provide new opportunities for rehabilitation in inpatients who are earlier in their recovery. Methods We designed a “virtually minimal” approach using robot-rendered haptics in a virtual environment to train severely injured inpatients in the early stages of recovery to sustain attention to a visuo-motor task. 21 inpatients with severe TBI completed repetitive reaching toward targets that were both seen and felt. Patients were tested over two consecutive days, experiencing 3 conditions (no haptic feedback, a break-through force, and haptic nudge) in 12 successive, 4-minute blocks. Results The interactive visuo-haptic environments were well-tolerated and engaging. Patients typically remained attentive to the task. However, patients exhibited attention loss both before (prolonged initiation) and during (pauses during motion) a movement. Compared to no haptic feedback, patients benefited from haptic nudge cues but not break-through forces. As training progressed, patients increased the number of targets acquired and spontaneously improved from one day to the next. Conclusions Interactive visuo-haptic environments could be beneficial for attention training for severe TBI patients in the early stages of recovery and warrants further and more prolonged clinical testing. PMID:23938101

  10. Haptograph Representation of Real-World Haptic Information by Wideband Force Control

    Science.gov (United States)

    Katsura, Seiichiro; Irie, Kouhei; Ohishi, Kiyoshi

    Artificial acquisition and reproduction of human sensations are basic technologies of communication engineering. For example, auditory information is obtained by a microphone, and a speaker reproduces it by artificial means. Furthermore, a video camera and a television make it possible to transmit visual sensation by broadcasting. On the contrary, since tactile or haptic information is subject to the Newton's “law of action and reaction” in the real world, a device which acquires, transmits, and reproduces the information has not been established. From the point of view, real-world haptics is the key technology for future haptic communication engineering. This paper proposes a novel acquisition method of haptic information named “haptograph”. The haptograph visualizes the haptic information like photograph. The proposed haptograph is applied to haptic recognition of the contact environment. A linear motor contacts to the surface of the environment and its reaction force is used to make a haptograph. A robust contact motion and sensor-less sensing of the reaction force are attained by using a disturbance observer. As a result, an encyclopedia of contact environment is attained. Since temporal and spatial analyses are conducted to represent haptic information as the haptograph, it is possible to be recognized and to be evaluated intuitively.

  11. Visuo-Haptic Mixed Reality with Unobstructed Tool-Hand Integration.

    Science.gov (United States)

    Cosco, Francesco; Garre, Carlos; Bruno, Fabio; Muzzupappa, Maurizio; Otaduy, Miguel A

    2013-01-01

    Visuo-haptic mixed reality consists of adding to a real scene the ability to see and touch virtual objects. It requires the use of see-through display technology for visually mixing real and virtual objects, and haptic devices for adding haptic interaction with the virtual objects. Unfortunately, the use of commodity haptic devices poses obstruction and misalignment issues that complicate the correct integration of a virtual tool and the user's real hand in the mixed reality scene. In this work, we propose a novel mixed reality paradigm where it is possible to touch and see virtual objects in combination with a real scene, using commodity haptic devices, and with a visually consistent integration of the user's hand and the virtual tool. We discuss the visual obstruction and misalignment issues introduced by commodity haptic devices, and then propose a solution that relies on four simple technical steps: color-based segmentation of the hand, tracking-based segmentation of the haptic device, background repainting using image-based models, and misalignment-free compositing of the user's hand. We have developed a successful proof-of-concept implementation, where a user can touch virtual objects and interact with them in the context of a real scene, and we have evaluated the impact on user performance of obstruction and misalignment correction.

  12. Shifty: A Weight-Shifting Dynamic Passive Haptic Proxy to Enhance Object Perception in Virtual Reality.

    Science.gov (United States)

    Zenner, Andre; Kruger, Antonio

    2017-04-01

    We define the concept of Dynamic Passive Haptic Feedback (DPHF) for virtual reality by introducing the weight-shifting physical DPHF proxy object Shifty. This concept combines actuators known from active haptics and physical proxies known from passive haptics to construct proxies that automatically adapt their passive haptic feedback. We describe the concept behind our ungrounded weight-shifting DPHF proxy Shifty and the implementation of our prototype. We then investigate how Shifty can, by automatically changing its internal weight distribution, enhance the user's perception of virtual objects interacted with in two experiments. In a first experiment, we show that Shifty can enhance the perception of virtual objects changing in shape, especially in length and thickness. Here, Shifty was shown to increase the user's fun and perceived realism significantly, compared to an equivalent passive haptic proxy. In a second experiment, Shifty is used to pick up virtual objects of different virtual weights. The results show that Shifty enhances the perception of weight and thus the perceived realism by adapting its kinesthetic feedback to the picked-up virtual object. In the same experiment, we additionally show that specific combinations of haptic, visual and auditory feedback during the pick-up interaction help to compensate for visual-haptic mismatch perceived during the shifting process.

  13. A "virtually minimal" visuo-haptic training of attention in severe traumatic brain injury.

    Science.gov (United States)

    Dvorkin, Assaf Y; Ramaiya, Milan; Larson, Eric B; Zollman, Felise S; Hsu, Nancy; Pacini, Sonia; Shah, Amit; Patton, James L

    2013-08-09

    Although common during the early stages of recovery from severe traumatic brain injury (TBI), attention deficits have been scarcely investigated. Encouraging evidence suggests beneficial effects of attention training in more chronic and higher functioning patients. Interactive technology may provide new opportunities for rehabilitation in inpatients who are earlier in their recovery. We designed a "virtually minimal" approach using robot-rendered haptics in a virtual environment to train severely injured inpatients in the early stages of recovery to sustain attention to a visuo-motor task. 21 inpatients with severe TBI completed repetitive reaching toward targets that were both seen and felt. Patients were tested over two consecutive days, experiencing 3 conditions (no haptic feedback, a break-through force, and haptic nudge) in 12 successive, 4-minute blocks. The interactive visuo-haptic environments were well-tolerated and engaging. Patients typically remained attentive to the task. However, patients exhibited attention loss both before (prolonged initiation) and during (pauses during motion) a movement. Compared to no haptic feedback, patients benefited from haptic nudge cues but not break-through forces. As training progressed, patients increased the number of targets acquired and spontaneously improved from one day to the next. Interactive visuo-haptic environments could be beneficial for attention training for severe TBI patients in the early stages of recovery and warrants further and more prolonged clinical testing.

  14. Inflationary scenario from higher curvature warped spacetime

    International Nuclear Information System (INIS)

    Banerjee, Narayan; Paul, Tanmoy

    2017-01-01

    We consider a five dimensional warped spacetime, in presence of the higher curvature term like F(R) = R + αR 2 in the bulk, in the context of the two-brane model. Our universe is identified with the TeV scale brane and emerges as a four dimensional effective theory. From the perspective of this effective theory, we examine the possibility of ''inflationary scenario'' by considering the on-brane metric ansatz as an FRW one. Our results reveal that the higher curvature term in the five dimensional bulk spacetime generates a potential term for the radion field. Due to the presence of radion potential, the very early universe undergoes a stage of accelerated expansion and, moreover, the accelerating period of the universe terminates in a finite time. We also find the spectral index of curvature perturbation (n s ) and the tensor to scalar ratio (r) in the present context, which match with the observational results based on the observations of Planck (Astron. Astrophys. 594, A20, 2016). (orig.)

  15. Inflationary scenario from higher curvature warped spacetime

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, Narayan [Indian Institute of Science Education and Research Kolkata, Department of Physical Sciences, Nadia, West Bengal (India); Paul, Tanmoy [Indian Association for the Cultivation of Science, Department of Theoretical Physics, Kolkata (India)

    2017-10-15

    We consider a five dimensional warped spacetime, in presence of the higher curvature term like F(R) = R + αR{sup 2} in the bulk, in the context of the two-brane model. Our universe is identified with the TeV scale brane and emerges as a four dimensional effective theory. From the perspective of this effective theory, we examine the possibility of ''inflationary scenario'' by considering the on-brane metric ansatz as an FRW one. Our results reveal that the higher curvature term in the five dimensional bulk spacetime generates a potential term for the radion field. Due to the presence of radion potential, the very early universe undergoes a stage of accelerated expansion and, moreover, the accelerating period of the universe terminates in a finite time. We also find the spectral index of curvature perturbation (n{sub s}) and the tensor to scalar ratio (r) in the present context, which match with the observational results based on the observations of Planck (Astron. Astrophys. 594, A20, 2016). (orig.)

  16. Haptic feedback can provide an objective assessment of arthroscopic skills.

    Science.gov (United States)

    Chami, George; Ward, James W; Phillips, Roger; Sherman, Kevin P

    2008-04-01

    The outcome of arthroscopic procedures is related to the surgeon's skills in arthroscopy. Currently, evaluation of such skills relies on direct observation by a surgeon trainer. This type of assessment, by its nature, is subjective and time-consuming. The aim of our study was to identify whether haptic information generated from arthroscopic tools could distinguish between skilled and less skilled surgeons. A standard arthroscopic probe was fitted with a force/torque sensor. The probe was used by five surgeons with different levels of experience in knee arthroscopy performing 11 different tasks in 10 standard knee arthroscopies. The force/torque data from the hand and tool interface were recorded and synchronized with a video recording of the procedure. The torque magnitude and patterns generated were analyzed and compared. A computerized system was used to analyze the force/torque signature based on general principles for quality of performance using such measures as economy in movement, time efficiency, and consistency in performance. The results showed a considerable correlation between three haptic parameters and the surgeon's experience, which could be used in an automated objective assessment system for arthroscopic surgery. Level II, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

  17. A haptic unit designed for magnetic-resonance-guided biopsy.

    Science.gov (United States)

    Tse, Z T H; Elhawary, H; Rea, M; Young, I; Davis, B L; Lamperth, M

    2009-02-01

    The magnetic fields present in the magnetic resonance (MR) environment impose severe constraints on any mechatronic device present in its midst, requiring alternative actuators, sensors, and materials to those conventionally used in traditional system engineering. In addition the spatial constraints of closed-bore scanners require a physical separation between the radiologist and the imaged region of the patient. This configuration produces a loss of the sense of touch from the target anatomy for the clinician, which often provides useful information. To recover the force feedback from the tissue, an MR-compatible haptic unit, designed to be integrated with a five-degrees-of-freedom mechatronic system for MR-guided prostate biopsy, has been developed which incorporates position control and force feedback to the operator. The haptic unit is designed to be located inside the scanner isocentre with the master console in the control room. MR compatibility of the device has been demonstrated, showing a negligible degradation of the signal-to-noise ratio and virtually no geometric distortion. By combining information from the position encoder and force sensor, tissue stiffness measurement along the needle trajectory is demonstrated in a lamb liver to aid diagnosis of suspected cancerous tissue.

  18. A real-time haptic interface for interventional radiology procedures.

    Science.gov (United States)

    Moix, Thomas; Ilic, Dejan; Fracheboud, Blaise; Zoethout, Jurjen; Bleuler, Hannes

    2005-01-01

    Interventional Radiology (IR) is a minimally-invasive surgery technique (MIS) where guidewires and catheters are steered in the vascular system under X-ray imaging. In order to perform these procedures, a radiologist has to be correctly trained to master hand-eye coordination, instrument manipulation and procedure protocols. This paper proposes a computer-assisted training environment dedicated to IR. The system is composed of a virtual reality (VR) simulation of the anatomy of the patient linked to a robotic interface providing haptic force feedback.The paper focuses on the requirements, design and prototyping of a specific part of the haptic interface dedicated to catheters. Translational tracking and force feedback on the catheter is provided by two cylinders forming a friction drive arrangement. The whole friction can be set in rotation with an additional motor providing torque feedback. A force and a torque sensor are integrated in the cylinders for direct measurement on the catheter enabling disturbance cancellation with a close-loop force control strategy.

  19. Touch Is Everywhere: Floor Surfaces as Ambient Haptic Interfaces.

    Science.gov (United States)

    Visell, Y; Law, A; Cooperstock, J R

    2009-01-01

    Floor surfaces are notable for the diverse roles that they play in our negotiation of everyday environments. Haptic communication via floor surfaces could enhance or enable many computer-supported activities that involve movement on foot. In this paper, we discuss potential applications of such interfaces in everyday environments and present a haptically augmented floor component through which several interaction methods are being evaluated. We describe two approaches to the design of structured vibrotactile signals for this device. The first is centered on a musical phrase metaphor, as employed in prior work on tactile display. The second is based upon the synthesis of rhythmic patterns of virtual physical impact transients. We report on an experiment in which participants were able to identify communication units that were constructed from these signals and displayed via a floor interface at well above chance levels. The results support the feasibility of tactile information display via such interfaces and provide further indications as to how to effectively design vibrotactile signals for them.

  20. Rhythmic Haptic Stimuli Improve Short-Term Attention.

    Science.gov (United States)

    Zhang, Shusheng; Wang, Dangxiao; Afzal, Naqash; Zhang, Yuru; Wu, Ruilin

    2016-01-01

    Brainwave entrainment using rhythmic visual and/or auditory stimulation has shown its efficacy in modulating neural activities and cognitive ability. In the presented study, we aim to investigate whether rhythmic haptic stimulation could enhance short-term attention. An experiment with sensorimotor rhythm (SMR) increasing protocol was performed in which participants were presented sinusoidal vibrotactile stimulus of 15 Hz on their palm. Test of Variables of Attention (T.O.V.A.) was performed before and after the stimulating session. Electroencephalograph (EEG) was recorded across the stimulating session and the two attention test sessions. SMR band power manifested a significant increase after stimulation. Results of T.O.V.A. tests indicated an improvement in the attention of participants who had received the stimulation compared to the control group who had not received the stimulation. The D prime score of T.O.V.A. reveals that participants performed better in perceptual sensitivity and sustaining attention level compared to their baseline performance before the stimulating session. These findings highlight the potential value of using haptics-based brainwave entrainment for cognitive training.

  1. An investigation of a passively controlled haptic interface

    Energy Technology Data Exchange (ETDEWEB)

    Davis, J.T. [Oak Ridge National Lab., TN (United States); Book, W.J. [Georgia Inst. of Tech., Atlanta, GA (United States). School of Mechanical Engineering

    1997-03-01

    Haptic interfaces enhance cooperation between humans and robotic manipulators by providing force and tactile feedback to the human user during the execution of arbitrary tasks. The use of active actuators in haptic displays presents a certain amount of risk since they are capable of providing unacceptable levels of energy to the systems upon which they operate. An alternative to providing numerous safeguards is to remove the sources of risk altogether. This research investigates the feasibility of trajectory control using passive devices, that is, devices that cannot add energy to the system. Passive actuators are capable only of removing energy from the system or transferring energy within the system. It is proposed that the utility of passive devices is greatly enhanced by the use of redundant actuators. In a passive system, once motion is provided to the system, presumably by a human user, passive devices may be able to modify this motion to achieve a desired resultant trajectory. A mechanically passive, 2-Degree-of-Freedom (D.O.F.) manipulator has been designed and built. It is equipped with four passive actuators: two electromagnetic brakes and two electromagnetic clutches. This paper gives a review of the literature on passive and robotics and describes the experimental test bed used in this research. Several control algorithms are investigated, resulting in the formulation of a passive control law.

  2. Wearable Vibrotactile Haptic Device for Stiffness Discrimination during Virtual Interactions

    Directory of Open Access Journals (Sweden)

    Andualem Tadesse Maereg

    2017-09-01

    Full Text Available In this paper, we discuss the development of cost effective, wireless, and wearable vibrotactile haptic device for stiffness perception during an interaction with virtual objects. Our experimental setup consists of haptic device with five vibrotactile actuators, virtual reality environment tailored in Unity 3D integrating the Oculus Rift Head Mounted Display (HMD and the Leap Motion controller. The virtual environment is able to capture touch inputs from users. Interaction forces are then rendered at 500 Hz and fed back to the wearable setup stimulating fingertips with ERM vibrotactile actuators. Amplitude and frequency of vibrations are modulated proportionally to the interaction force to simulate the stiffness of a virtual object. A quantitative and qualitative study is done to compare the discrimination of stiffness on virtual linear spring in three sensory modalities: visual only feedback, tactile only feedback, and their combination. A common psychophysics method called the Two Alternative Forced Choice (2AFC approach is used for quantitative analysis using Just Noticeable Difference (JND and Weber Fractions (WF. According to the psychometric experiment result, average Weber fraction values of 0.39 for visual only feedback was improved to 0.25 by adding the tactile feedback.

  3. Functional Contour-following via Haptic Perception and Reinforcement Learning.

    Science.gov (United States)

    Hellman, Randall B; Tekin, Cem; van der Schaar, Mihaela; Santos, Veronica J

    2018-01-01

    Many tasks involve the fine manipulation of objects despite limited visual feedback. In such scenarios, tactile and proprioceptive feedback can be leveraged for task completion. We present an approach for real-time haptic perception and decision-making for a haptics-driven, functional contour-following task: the closure of a ziplock bag. This task is challenging for robots because the bag is deformable, transparent, and visually occluded by artificial fingertip sensors that are also compliant. A deep neural net classifier was trained to estimate the state of a zipper within a robot's pinch grasp. A Contextual Multi-Armed Bandit (C-MAB) reinforcement learning algorithm was implemented to maximize cumulative rewards by balancing exploration versus exploitation of the state-action space. The C-MAB learner outperformed a benchmark Q-learner by more efficiently exploring the state-action space while learning a hard-to-code task. The learned C-MAB policy was tested with novel ziplock bag scenarios and contours (wire, rope). Importantly, this work contributes to the development of reinforcement learning approaches that account for limited resources such as hardware life and researcher time. As robots are used to perform complex, physically interactive tasks in unstructured or unmodeled environments, it becomes important to develop methods that enable efficient and effective learning with physical testbeds.

  4. An investigation of a passively controlled haptic interface

    International Nuclear Information System (INIS)

    Davis, J.T.; Book, W.J.

    1997-01-01

    Haptic interfaces enhance cooperation between humans and robotic manipulators by providing force and tactile feedback to the human user during the execution of arbitrary tasks. The use of active actuators in haptic displays presents a certain amount of risk since they are capable of providing unacceptable levels of energy to the systems upon which they operate. An alternative to providing numerous safeguards is to remove the sources of risk altogether. This research investigates the feasibility of trajectory control using passive devices, that is, devices that cannot add energy to the system. Passive actuators are capable only of removing energy from the system or transferring energy within the system. It is proposed that the utility of passive devices is greatly enhanced by the use of redundant actuators. In a passive system, once motion is provided to the system, presumably by a human user, passive devices may be able to modify this motion to achieve a desired resultant trajectory. A mechanically passive, 2-Degree-of-Freedom (D.O.F.) manipulator has been designed and built. It is equipped with four passive actuators: two electromagnetic brakes and two electromagnetic clutches. This paper gives a review of the literature on passive and robotics and describes the experimental test bed used in this research. Several control algorithms are investigated, resulting in the formulation of a passive control law

  5. Assignment about providing of substitute haptic interface for visually disabled persons

    OpenAIRE

    浅川, 貴史

    2013-01-01

    [Abstract] This paper is described about an assignment of haptic interface. We have made a proposal for a music baton system for visually disabled persons. The system is constituted by an acceleration sensor, a radio module, and a haptic interface device. We have carried out an experiment of comparing the visual and the haptic interface. The assignments are declared by the results that are rise-time of a motor and pre-motion. In the paper, we make a proposal for new method of the voltage cont...

  6. Study of Electric Music Baton using Haptic Interface for Assistance of Visually Disabled Persons

    OpenAIRE

    浅川, 貴史

    2012-01-01

    [Abstract] We have made a proposal for a music baton system for visual disabled persons. The system is constituted by an acceleration sensor, a radio module, and a haptic interface device. When a conductor moves the baton, Players are able to acknowledge the action using the haptic interface device. We have carried out an experiment of comparing the visual and the haptic interface. The result declared that a pre-motion is important for the visual interface. In the paper, we make a proposal fo...

  7. Distributed mean curvature on a discrete manifold for Regge calculus

    International Nuclear Information System (INIS)

    Conboye, Rory; Miller, Warner A; Ray, Shannon

    2015-01-01

    The integrated mean curvature of a simplicial manifold is well understood in both Regge Calculus and Discrete Differential Geometry. However, a well motivated pointwise definition of curvature requires a careful choice of the volume over which to uniformly distribute the local integrated curvature. We show that hybrid cells formed using both the simplicial lattice and its circumcentric dual emerge as a remarkably natural structure for the distribution of this local integrated curvature. These hybrid cells form a complete tessellation of the simplicial manifold, contain a geometric orthonormal basis, and are also shown to give a pointwise mean curvature with a natural interpretation as the fractional rate of change of the normal vector. (paper)

  8. Distributed mean curvature on a discrete manifold for Regge calculus

    Science.gov (United States)

    Conboye, Rory; Miller, Warner A.; Ray, Shannon

    2015-09-01

    The integrated mean curvature of a simplicial manifold is well understood in both Regge Calculus and Discrete Differential Geometry. However, a well motivated pointwise definition of curvature requires a careful choice of the volume over which to uniformly distribute the local integrated curvature. We show that hybrid cells formed using both the simplicial lattice and its circumcentric dual emerge as a remarkably natural structure for the distribution of this local integrated curvature. These hybrid cells form a complete tessellation of the simplicial manifold, contain a geometric orthonormal basis, and are also shown to give a pointwise mean curvature with a natural interpretation as the fractional rate of change of the normal vector.

  9. A curvature theory for discrete surfaces based on mesh parallelity

    KAUST Repository

    Bobenko, Alexander Ivanovich

    2009-12-18

    We consider a general theory of curvatures of discrete surfaces equipped with edgewise parallel Gauss images, and where mean and Gaussian curvatures of faces are derived from the faces\\' areas and mixed areas. Remarkably these notions are capable of unifying notable previously defined classes of surfaces, such as discrete isothermic minimal surfaces and surfaces of constant mean curvature. We discuss various types of natural Gauss images, the existence of principal curvatures, constant curvature surfaces, Christoffel duality, Koenigs nets, contact element nets, s-isothermic nets, and interesting special cases such as discrete Delaunay surfaces derived from elliptic billiards. © 2009 Springer-Verlag.

  10. Frontoparietal white matter integrity predicts haptic performance in chronic stroke

    Directory of Open Access Journals (Sweden)

    Alexandra L. Borstad

    2016-01-01

    Full Text Available Frontoparietal white matter supports information transfer between brain areas involved in complex haptic tasks such as somatosensory discrimination. The purpose of this study was to gain an understanding of the relationship between microstructural integrity of frontoparietal network white matter and haptic performance in persons with chronic stroke and to compare frontoparietal network integrity in participants with stroke and age matched control participants. Nineteen individuals with stroke and 16 controls participated. Haptic performance was quantified using the Hand Active Sensation Test (HASTe, an 18-item match-to-sample test of weight and texture discrimination. Three tesla MRI was used to obtain diffusion-weighted and high-resolution anatomical images of the whole brain. Probabilistic tractography was used to define 10 frontoparietal tracts total; Four intrahemispheric tracts measured bilaterally 1 thalamus to primary somatosensory cortex (T–S1, 2 thalamus to primary motor cortex (T–M1, 3 primary to secondary somatosensory cortex (S1 to SII and 4 primary somatosensory cortex to middle frontal gyrus (S1 to MFG and, 2 interhemispheric tracts; S1–S1 and precuneus interhemispheric. A control tract outside the network, the cuneus interhemispheric tract, was also examined. The diffusion metrics fractional anisotropy (FA, mean diffusivity (MD, axial (AD and radial diffusivity (RD were quantified for each tract. Diminished FA and elevated MD values are associated with poorer white matter integrity in chronic stroke. Nine of 10 tracts quantified in the frontoparietal network had diminished structural integrity poststroke compared to the controls. The precuneus interhemispheric tract was not significantly different between groups. Principle component analysis across all frontoparietal white matter tract MD values indicated a single factor explained 47% and 57% of the variance in tract mean diffusivity in stroke and control groups respectively

  11. Frontoparietal white matter integrity predicts haptic performance in chronic stroke.

    Science.gov (United States)

    Borstad, Alexandra L; Choi, Seongjin; Schmalbrock, Petra; Nichols-Larsen, Deborah S

    2016-01-01

    Frontoparietal white matter supports information transfer between brain areas involved in complex haptic tasks such as somatosensory discrimination. The purpose of this study was to gain an understanding of the relationship between microstructural integrity of frontoparietal network white matter and haptic performance in persons with chronic stroke and to compare frontoparietal network integrity in participants with stroke and age matched control participants. Nineteen individuals with stroke and 16 controls participated. Haptic performance was quantified using the Hand Active Sensation Test (HASTe), an 18-item match-to-sample test of weight and texture discrimination. Three tesla MRI was used to obtain diffusion-weighted and high-resolution anatomical images of the whole brain. Probabilistic tractography was used to define 10 frontoparietal tracts total; Four intrahemispheric tracts measured bilaterally 1) thalamus to primary somatosensory cortex (T-S1), 2) thalamus to primary motor cortex (T-M1), 3) primary to secondary somatosensory cortex (S1 to SII) and 4) primary somatosensory cortex to middle frontal gyrus (S1 to MFG) and, 2 interhemispheric tracts; S1-S1 and precuneus interhemispheric. A control tract outside the network, the cuneus interhemispheric tract, was also examined. The diffusion metrics fractional anisotropy (FA), mean diffusivity (MD), axial (AD) and radial diffusivity (RD) were quantified for each tract. Diminished FA and elevated MD values are associated with poorer white matter integrity in chronic stroke. Nine of 10 tracts quantified in the frontoparietal network had diminished structural integrity poststroke compared to the controls. The precuneus interhemispheric tract was not significantly different between groups. Principle component analysis across all frontoparietal white matter tract MD values indicated a single factor explained 47% and 57% of the variance in tract mean diffusivity in stroke and control groups respectively. Age

  12. Haptic, Virtual Interaction and Motor Imagery: Entertainment Tools and Psychophysiological Testing.

    Science.gov (United States)

    Invitto, Sara; Faggiano, Chiara; Sammarco, Silvia; De Luca, Valerio; De Paolis, Lucio T

    2016-03-18

    In this work, the perception of affordances was analysed in terms of cognitive neuroscience during an interactive experience in a virtual reality environment. In particular, we chose a virtual reality scenario based on the Leap Motion controller: this sensor device captures the movements of the user's hand and fingers, which are reproduced on a computer screen by the proper software applications. For our experiment, we employed a sample of 10 subjects matched by age and sex and chosen among university students. The subjects took part in motor imagery training and immersive affordance condition (a virtual training with Leap Motion and a haptic training with real objects). After each training sessions the subject performed a recognition task, in order to investigate event-related potential (ERP) components. The results revealed significant differences in the attentional components during the Leap Motion training. During Leap Motion session, latencies increased in the occipital lobes, which are entrusted to visual sensory; in contrast, latencies decreased in the frontal lobe, where the brain is mainly activated for attention and action planning.

  13. Haptic, Virtual Interaction and Motor Imagery: Entertainment Tools and Psychophysiological Testing

    Directory of Open Access Journals (Sweden)

    Sara Invitto

    2016-03-01

    Full Text Available In this work, the perception of affordances was analysed in terms of cognitive neuroscience during an interactive experience in a virtual reality environment. In particular, we chose a virtual reality scenario based on the Leap Motion controller: this sensor device captures the movements of the user’s hand and fingers, which are reproduced on a computer screen by the proper software applications. For our experiment, we employed a sample of 10 subjects matched by age and sex and chosen among university students. The subjects took part in motor imagery training and immersive affordance condition (a virtual training with Leap Motion and a haptic training with real objects. After each training sessions the subject performed a recognition task, in order to investigate event-related potential (ERP components. The results revealed significant differences in the attentional components during the Leap Motion training. During Leap Motion session, latencies increased in the occipital lobes, which are entrusted to visual sensory; in contrast, latencies decreased in the frontal lobe, where the brain is mainly activated for attention and action planning.

  14. Haptic, Virtual Interaction and Motor Imagery: Entertainment Tools and Psychophysiological Testing

    Science.gov (United States)

    Invitto, Sara; Faggiano, Chiara; Sammarco, Silvia; De Luca, Valerio; De Paolis, Lucio T.

    2016-01-01

    In this work, the perception of affordances was analysed in terms of cognitive neuroscience during an interactive experience in a virtual reality environment. In particular, we chose a virtual reality scenario based on the Leap Motion controller: this sensor device captures the movements of the user’s hand and fingers, which are reproduced on a computer screen by the proper software applications. For our experiment, we employed a sample of 10 subjects matched by age and sex and chosen among university students. The subjects took part in motor imagery training and immersive affordance condition (a virtual training with Leap Motion and a haptic training with real objects). After each training sessions the subject performed a recognition task, in order to investigate event-related potential (ERP) components. The results revealed significant differences in the attentional components during the Leap Motion training. During Leap Motion session, latencies increased in the occipital lobes, which are entrusted to visual sensory; in contrast, latencies decreased in the frontal lobe, where the brain is mainly activated for attention and action planning. PMID:26999151

  15. 77 FR 15390 - Certain Mobile Electronic Devices Incorporating Haptics; Receipt of Amended Complaint...

    Science.gov (United States)

    2012-03-15

    ... INTERNATIONAL TRADE COMMISSION [DN 2875] Certain Mobile Electronic Devices Incorporating Haptics.... International Trade Commission. ACTION: Notice. SUMMARY: Notice is hereby given that the U.S. International Trade Commission has received an amended complaint entitled Certain Mobile Electronic Devices...

  16. Design of a Magnetic Resonance-Safe Haptic Wrist Manipulator for Movement Disorder Diagnostics

    NARCIS (Netherlands)

    Bode, Dyon; Mugge, Winfred; Schouten, Alfred C.; van Rootselaar, Anne-Fleur; Bour, Lo J.; van der Helm, Frans C. T.; Lammertse, Piet

    2017-01-01

    Tremor, characterized by involuntary and rhythmical movements, is the most common movement disorder. Tremor can have peripheral and central oscillatory components which properly assessed may improve diagnostics. A magnetic resonance (MR)-safe haptic wrist manipulator enables simultaneous measurement

  17. Dynamics modeling for parallel haptic interfaces with force sensing and control.

    Science.gov (United States)

    Bernstein, Nicholas; Lawrence, Dale; Pao, Lucy

    2013-01-01

    Closed-loop force control can be used on haptic interfaces (HIs) to mitigate the effects of mechanism dynamics. A single multidimensional force-torque sensor is often employed to measure the interaction force between the haptic device and the user's hand. The parallel haptic interface at the University of Colorado (CU) instead employs smaller 1D force sensors oriented along each of the five actuating rods to build up a 5D force vector. This paper shows that a particular manipulandum/hand partition in the system dynamics is induced by the placement and type of force sensing, and discusses the implications on force and impedance control for parallel haptic interfaces. The details of a "squaring down" process are also discussed, showing how to obtain reduced degree-of-freedom models from the general six degree-of-freedom dynamics formulation.

  18. Operator dynamics for stability condition in haptic and teleoperation system: A survey.

    Science.gov (United States)

    Li, Hongbing; Zhang, Lei; Kawashima, Kenji

    2018-04-01

    Currently, haptic systems ignore the varying impedance of the human hand with its countless configurations and thus cannot recreate the complex haptic interactions. The literature does not reveal a comprehensive survey on the methods proposed and this study is an attempt to bridge this gap. The paper includes an extensive review of human arm impedance modeling and control deployed to address inherent stability and transparency issues in haptic interaction and teleoperation systems. Detailed classification and comparative study of various contributions in human arm modeling are presented and summarized in tables and diagrams. The main challenges in modeling human arm impedance for haptic robotic applications are identified. The possible future research directions are outlined based on the gaps identified in the survey. Copyright © 2018 John Wiley & Sons, Ltd.

  19. Zero curvature-surface driven small objects

    Science.gov (United States)

    Dou, Xiaoxiao; Li, Shanpeng; Liu, Jianlin

    2017-08-01

    In this study, we investigate the spontaneous migration of small objects driven by surface tension on a catenoid, formed by a layer of soap constrained by two rings. Although the average curvature of the catenoid is zero at each point, the small objects always migrate to the position near the ring. The force and energy analyses have been performed to uncover the mechanism, and it is found that the small objects distort the local shape of the liquid film, thus making the whole system energetically favorable. These findings provide some inspiration to design microfluidics, aquatic robotics, and miniature boats.

  20. Spacetime Curvature and Higgs Stability after Inflation.

    Science.gov (United States)

    Herranen, M; Markkanen, T; Nurmi, S; Rajantie, A

    2015-12-11

    We investigate the dynamics of the Higgs field at the end of inflation in the minimal scenario consisting of an inflaton field coupled to the standard model only through the nonminimal gravitational coupling ξ of the Higgs field. Such a coupling is required by renormalization of the standard model in curved space, and in the current scenario also by vacuum stability during high-scale inflation. We find that for ξ≳1, rapidly changing spacetime curvature at the end of inflation leads to significant production of Higgs particles, potentially triggering a transition to a negative-energy Planck scale vacuum state and causing an immediate collapse of the Universe.

  1. Constraining inverse-curvature gravity with supernovae.

    Science.gov (United States)

    Mena, Olga; Santiago, José; Weller, Jochen

    2006-02-03

    We show that models of generalized modified gravity, with inverse powers of the curvature, can explain the current accelerated expansion of the Universe without resorting to dark energy and without conflicting with solar system experiments. We have solved the Friedmann equations for the full dynamical range of the evolution of the Universe and performed a detailed analysis of supernovae data in the context of such models that results in an excellent fit. If we further include constraints on the current expansion of the Universe and on its age, we obtain that the matter content of the Universe is 0.07baryonic matter component.

  2. Amplification of curvature perturbations in cyclic cosmology

    International Nuclear Information System (INIS)

    Zhang Jun; Liu Zhiguo; Piao Yunsong

    2010-01-01

    We analytically and numerically show that through the cycles with nonsingular bounce, the amplitude of curvature perturbation on a large scale will be amplified and the power spectrum will redden. In some sense, this amplification will eventually destroy the homogeneity of the background, which will lead to the ultimate end of cycles of the global universe. We argue that for the model with increasing cycles, it might be possible that a fissiparous multiverse will emerge after one or several cycles, in which the cycles will continue only at corresponding local regions.

  3. Curvature, zero modes and quantum statistics

    Energy Technology Data Exchange (ETDEWEB)

    Calixto, M [Departamento de Matematica Aplicada y EstadIstica, Universidad Politecnica de Cartagena, Paseo Alfonso XIII 56, 30203 Cartagena (Spain); Aldaya, V [Instituto de AstrofIsica de AndalucIa, Apartado Postal 3004, 18080 Granada (Spain)

    2006-08-18

    We explore an intriguing connection between the Fermi-Dirac and Bose-Einstein statistics and the thermal baths obtained from a vacuum radiation of coherent states of zero modes in a second quantized (many-particle) theory on the compact O(3) and noncompact O(2, 1) isometry subgroups of the de Sitter and anti-de Sitter spaces, respectively. The high frequency limit is retrieved as a (zero-curvature) group contraction to the Newton-Hooke (harmonic oscillator) group. We also make some comments on the vacuum energy density and the cosmological constant problem. (letter to the editor)

  4. Differential geometry bundles, connections, metrics and curvature

    CERN Document Server

    Taubes, Clifford Henry

    2011-01-01

    Bundles, connections, metrics and curvature are the 'lingua franca' of modern differential geometry and theoretical physics. This book will supply a graduate student in mathematics or theoretical physics with the fundamentals of these objects. Many of the tools used in differential topology are introduced and the basic results about differentiable manifolds, smooth maps, differential forms, vector fields, Lie groups, and Grassmanians are all presented here. Other material covered includes the basic theorems about geodesics and Jacobi fields, the classification theorem for flat connections, the

  5. Curvature and temperature of complex networks.

    Science.gov (United States)

    Krioukov, Dmitri; Papadopoulos, Fragkiskos; Vahdat, Amin; Boguñá, Marián

    2009-09-01

    We show that heterogeneous degree distributions in observed scale-free topologies of complex networks can emerge as a consequence of the exponential expansion of hidden hyperbolic space. Fermi-Dirac statistics provides a physical interpretation of hyperbolic distances as energies of links. The hidden space curvature affects the heterogeneity of the degree distribution, while clustering is a function of temperature. We embed the internet into the hyperbolic plane and find a remarkable congruency between the embedding and our hyperbolic model. Besides proving our model realistic, this embedding may be used for routing with only local information, which holds significant promise for improving the performance of internet routing.

  6. Handling in the Micro/nano-world: haptic device

    International Nuclear Information System (INIS)

    Nigues, A.

    2012-09-01

    Synchrotron Radiation and Scanning Probe Microscopy (SPM) are among the most used techniques to study the physical and chemical properties of nano-structures. Coupling these two techniques is a promising path for opening new horizons in the study of nano-sciences. The merge has already proved its potentialities in the frame of the X-tip project where Atomic Force Microscopy (AFM) has been associated with synchrotron radiation X-Ray diffraction to determine the Young's modulus of germanium micro-plots by dynamically indenting the sample while performing diffraction analysis. The configuration used there, however, does not permit three dimension (3D) manipulations of samples. The aim of our nano-manipulator is 3D management of samples with permanent control of the nano-forces exerted on the object while immersed in a scanning beam (X-Ray, e-beams). The first chapter focuses on the sensors with which measure the interactions at a nanometer scale and permit the selection of individual objects. After an overview of the different techniques of micro/nano-manipulation available today (mechanical micro-grippers based on MEMS technology, optic tweezers or grippers based on conventional atomic force microscopy), and considering the constraints imposed by synchrotron experiments, the choice of quartz oscillators (Tuning Forks or Length Extended Resonators (LER)) as sensors is explained. It follows an introduction to Atomic Force Microscopy in general and the description of its association to these oscillators. In the second chapter, the instrumental development of our nano-manipulation station is detailed with particular care on the definition of the geometry of the resonators and related tips for achieving both AFM imaging and gripping of the sample and on the way to control the coarse and ne positioning of the three elements of the nano-manipulator. Finally, the haptic system ERGOS and its coupling with our assembly is described. In the last chapter, two types of

  7. The workload implications of haptic displays in multi-display environments such as the cockpit: Dual-task interference of within-sense haptic inputs (tactile/proprioceptive) and between-sense inputs (tactile/proprioceptive/auditory/visual)

    OpenAIRE

    Castle, H

    2007-01-01

    Visual workload demand within the cockpit is reaching saturation, whereas the haptic sense (proprioceptive and tactile sensation) is relatively untapped, despite studies suggesting the benefits of haptic displays. MRT suggests that inputs from haptic displays will not interfere with inputs from visual or auditory displays. MRT is based on the premise that multisensory integration occurs only after unisensory processing. However, recent neuroscientific findings suggest that t...

  8. Evaluation of Pseudo-Haptic Interactions with Soft Objects in Virtual Environments.

    Directory of Open Access Journals (Sweden)

    Min Li

    Full Text Available This paper proposes a pseudo-haptic feedback method conveying simulated soft surface stiffness information through a visual interface. The method exploits a combination of two feedback techniques, namely visual feedback of soft surface deformation and control of the indenter avatar speed, to convey stiffness information of a simulated surface of a soft object in virtual environments. The proposed method was effective in distinguishing different sizes of virtual hard nodules integrated into the simulated soft bodies. To further improve the interactive experience, the approach was extended creating a multi-point pseudo-haptic feedback system. A comparison with regards to (a nodule detection sensitivity and (b elapsed time as performance indicators in hard nodule detection experiments to a tablet computer incorporating vibration feedback was conducted. The multi-point pseudo-haptic interaction is shown to be more time-efficient than the single-point pseudo-haptic interaction. It is noted that multi-point pseudo-haptic feedback performs similarly well when compared to a vibration-based feedback method based on both performance measures elapsed time and nodule detection sensitivity. This proves that the proposed method can be used to convey detailed haptic information for virtual environmental tasks, even subtle ones, using either a computer mouse or a pressure sensitive device as an input device. This pseudo-haptic feedback method provides an opportunity for low-cost simulation of objects with soft surfaces and hard inclusions, as, for example, occurring in ever more realistic video games with increasing emphasis on interaction with the physical environment and minimally invasive surgery in the form of soft tissue organs with embedded cancer nodules. Hence, the method can be used in many low-budget applications where haptic sensation is required, such as surgeon training or video games, either using desktop computers or portable devices, showing

  9. Use of VR Technology and Passive Haptics for MANPADS Training System

    Science.gov (United States)

    2017-09-01

    reach satisfactory technical performance like latency and frame rate, while generating the sensory stimuli needed for this type of training —visual...release. Distribution is unlimited. USE OF VR TECHNOLOGY AND PASSIVE HAPTICS FOR MANPADS TRAINING SYSTEM by Faisal Rashid September 2017...HAPTICS FOR MANPADS TRAINING SYSTEM 5. FUNDING NUMBERS 6. AUTHOR(S) Faisal Rashid 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Naval

  10. A Three-Axis Force Sensor for Dual Finger Haptic Interfaces

    OpenAIRE

    Fontana, Marco; Marcheschi, Simone; Salsedo, Fabio; Bergamasco, Massimo

    2012-01-01

    In this work we present the design process, the characterization and testing of a novel three-axis mechanical force sensor. This sensor is optimized for use in closed-loop force control of haptic devices with three degrees of freedom. In particular the sensor has been conceived for integration with a dual finger haptic interface that aims at simulating forces that occur during grasping and surface exploration. The sensing spring structure has been purposely designed in order to match force an...

  11. Command Recognition of Robot with Low Dimension Whole-Body Haptic Sensor

    Science.gov (United States)

    Ito, Tatsuya; Tsuji, Toshiaki

    The authors have developed “haptic armor”, a whole-body haptic sensor that has an ability to estimate contact position. Although it is developed for safety assurance of robots in human environment, it can also be used as an interface. This paper proposes a command recognition method based on finger trace information. This paper also discusses some technical issues for improving recognition accuracy of this system.

  12. Feasibility Study of Haptic Display for Rotation Tasks of Wrist Work

    OpenAIRE

    曽根, 順治; 岩井, 秀樹; 山田, 勝実; 陳, 軍; 徳山, 喜政; 今野, 晃市; Sone, Junji; Iwai, Hideki; Yamada, Katsumi; Chen, Jun; Tokuyama, Yoshimasa; Konno, Kouichi

    2011-01-01

    We have developed a haptic display for rotational tasks that involve functions of the human wrist. We represent the torque using a motor and a brake. Reference torque curves are obtained by the measuring torque required for each actual task using a torque sensor. The brake represents the stop condition. We have confirmed the effectiveness of the display by comparing the actual tasks with the haptic display experiment.

  13. Stable haptic feedback based on a Dynamic Vision Sensor for Microrobotics.

    OpenAIRE

    Bolopion , Aude; Ni , Zhenjiang; Agnus , Joël; Benosman , Ryad; Régnier , Stéphane

    2012-01-01

    International audience; This work presents a stable vision based haptic feedback for micromanipulation using both an asynchronous Address Event Representation (AER) silicon retina and a conventional frame-based camera. At this scale, most of the grippers used to manipulate objects lack of force sensing. High frequency vision detection thus provides a sound solution to get information about the position of the object and the tool to provide virtual haptic guides. Artificial retinas present hig...

  14. Towards open-source, low-cost haptics for surgery simulation.

    Science.gov (United States)

    Suwelack, Stefan; Sander, Christian; Schill, Julian; Serf, Manuel; Danz, Marcel; Asfour, Tamim; Burger, Wolfgang; Dillmann, Rüdiger; Speidel, Stefanie

    2014-01-01

    In minimally invasive surgery (MIS), virtual reality (VR) training systems have become a promising education tool. However, the adoption of these systems in research and clinical settings is still limited by the high costs of dedicated haptics hardware for MIS. In this paper, we present ongoing research towards an open-source, low-cost haptic interface for MIS simulation. We demonstrate the basic mechanical design of the device, the sensor setup as well as its software integration.

  15. The effect of haptic guidance and visual feedback on learning a complex tennis task.

    Science.gov (United States)

    Marchal-Crespo, Laura; van Raai, Mark; Rauter, Georg; Wolf, Peter; Riener, Robert

    2013-11-01

    While haptic guidance can improve ongoing performance of a motor task, several studies have found that it ultimately impairs motor learning. However, some recent studies suggest that the haptic demonstration of optimal timing, rather than movement magnitude, enhances learning in subjects trained with haptic guidance. Timing of an action plays a crucial role in the proper accomplishment of many motor skills, such as hitting a moving object (discrete timing task) or learning a velocity profile (time-critical tracking task). The aim of the present study is to evaluate which feedback conditions-visual or haptic guidance-optimize learning of the discrete and continuous elements of a timing task. The experiment consisted in performing a fast tennis forehand stroke in a virtual environment. A tendon-based parallel robot connected to the end of a racket was used to apply haptic guidance during training. In two different experiments, we evaluated which feedback condition was more adequate for learning: (1) a time-dependent discrete task-learning to start a tennis stroke and (2) a tracking task-learning to follow a velocity profile. The effect that the task difficulty and subject's initial skill level have on the selection of the optimal training condition was further evaluated. Results showed that the training condition that maximizes learning of the discrete time-dependent motor task depends on the subjects' initial skill level. Haptic guidance was especially suitable for less-skilled subjects and in especially difficult discrete tasks, while visual feedback seems to benefit more skilled subjects. Additionally, haptic guidance seemed to promote learning in a time-critical tracking task, while visual feedback tended to deteriorate the performance independently of the task difficulty and subjects' initial skill level. Haptic guidance outperformed visual feedback, although additional studies are needed to further analyze the effect of other types of feedback visualization on

  16. Cognitive and tactile factors affecting human haptic performance in later life.

    Directory of Open Access Journals (Sweden)

    Tobias Kalisch

    Full Text Available BACKGROUND: Vision and haptics are the key modalities by which humans perceive objects and interact with their environment in a target-oriented manner. Both modalities share higher-order neural resources and the mechanisms required for object exploration. Compared to vision, the understanding of haptic information processing is still rudimentary. Although it is known that haptic performance, similar to many other skills, decreases in old age, the underlying mechanisms are not clear. It is yet to be determined to what extent this decrease is related to the age-related loss of tactile acuity or cognitive capacity. METHODOLOGY/PRINCIPAL FINDINGS: We investigated the haptic performance of 81 older adults by means of a cross-modal object recognition test. Additionally, we assessed the subjects' tactile acuity with an apparatus-based two-point discrimination paradigm, and their cognitive performance by means of the non-verbal Raven-Standard-Progressive matrices test. As expected, there was a significant age-related decline in performance on all 3 tests. With the exception of tactile acuity, this decline was found to be more distinct in female subjects. Correlation analyses revealed a strong relationship between haptic and cognitive performance for all subjects. Tactile performance, on the contrary, was only significantly correlated with male subjects' haptic performance. CONCLUSIONS: Haptic object recognition is a demanding task in old age, especially when it comes to the exploration of complex, unfamiliar objects. Our data support a disproportionately higher impact of cognition on haptic performance as compared to the impact of tactile acuity. Our findings are in agreement with studies reporting an increase in co-variation between individual sensory performance and general cognitive functioning in old age.

  17. Skin-Inspired Haptic Memory Arrays with an Electrically Reconfigurable Architecture.

    Science.gov (United States)

    Zhu, Bowen; Wang, Hong; Liu, Yaqing; Qi, Dianpeng; Liu, Zhiyuan; Wang, Hua; Yu, Jiancan; Sherburne, Matthew; Wang, Zhaohui; Chen, Xiaodong

    2016-02-24

    Skin-inspired haptic-memory devices, which can retain pressure information after the removel of external pressure by virtue of the nonvolatile nature of the memory devices, are achieved. The rise of haptic-memory devices will allow for mimicry of human sensory memory, opening new avenues for the design of next-generation high-performance sensing devices and systems. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. A Study on Immersion and Presence of a Portable Hand Haptic System for Immersive Virtual Reality.

    Science.gov (United States)

    Kim, Mingyu; Jeon, Changyu; Kim, Jinmo

    2017-05-17

    This paper proposes a portable hand haptic system using Leap Motion as a haptic interface that can be used in various virtual reality (VR) applications. The proposed hand haptic system was designed as an Arduino-based sensor architecture to enable a variety of tactile senses at low cost, and is also equipped with a portable wristband. As a haptic system designed for tactile feedback, the proposed system first identifies the left and right hands and then sends tactile senses (vibration and heat) to each fingertip (thumb and index finger). It is incorporated into a wearable band-type system, making its use easy and convenient. Next, hand motion is accurately captured using the sensor of the hand tracking system and is used for virtual object control, thus achieving interaction that enhances immersion. A VR application was designed with the purpose of testing the immersion and presence aspects of the proposed system. Lastly, technical and statistical tests were carried out to assess whether the proposed haptic system can provide a new immersive presence to users. According to the results of the presence questionnaire and the simulator sickness questionnaire, we confirmed that the proposed hand haptic system, in comparison to the existing interaction that uses only the hand tracking system, provided greater presence and a more immersive environment in the virtual reality.

  19. A magnetorheological fluid-based multifunctional haptic device for vehicular instrument controls

    International Nuclear Information System (INIS)

    Han, Young-Min; Kim, Chan-Jung; Choi, Seung-Bok

    2009-01-01

    This paper presents control performances of a magnetorheological (MR) fluid-based multifunctional haptic device which is applicable to vehicular instrument controls. By combining in-vehicle functions into a single device, the proposed haptic device can transmit various reflection forces for each comfort function to a driver without requiring the driver's visual attention. As a multifunctional haptic device, a MR knob is proposed in this work and then devised to be capable of both rotary and push motions with a single knob. Under consideration of the spatial limitations of vehicle dashboards, design parameters are optimally determined by finite element analysis, and the objective function is to maximize a relative control torque. The proposed haptic device is then manufactured, and in-vehicle comfort functions are constructed in a virtual environment which makes the functions to communicate with the haptic device. Subsequently, a feed-forward controller using torque/force maps is formulated for the force tracking control. Control performances such as reflection force of the haptic device are experimentally evaluated via the torque/force map-based feed-forward controller

  20. Design of a 4-DOF MR haptic master for application to robot surgery: virtual environment work

    Science.gov (United States)

    Oh, Jong-Seok; Choi, Seung-Hyun; Choi, Seung-Bok

    2014-09-01

    This paper presents the design and control performance of a novel type of 4-degrees-of-freedom (4-DOF) haptic master in cyberspace for a robot-assisted minimally invasive surgery (RMIS) application. By using a controllable magnetorheological (MR) fluid, the proposed haptic master can have a feedback function for a surgical robot. Due to the difficulty in utilizing real human organs in the experiment, the cyberspace that features the virtual object is constructed to evaluate the performance of the haptic master. In order to realize the cyberspace, a volumetric deformable object is represented by a shape-retaining chain-linked (S-chain) model, which is a fast volumetric model and is suitable for real-time applications. In the haptic architecture for an RMIS application, the desired torque and position induced from the virtual object of the cyberspace and the haptic master of real space are transferred to each other. In order to validate the superiority of the proposed master and volumetric model, a tracking control experiment is implemented with a nonhomogenous volumetric cubic object to demonstrate that the proposed model can be utilized in real-time haptic rendering architecture. A proportional-integral-derivative (PID) controller is then designed and empirically implemented to accomplish the desired torque trajectories. It has been verified from the experiment that tracking the control performance for torque trajectories from a virtual slave can be successfully achieved.

  1. Design of a 7-DOF slave robot integrated with a magneto-rheological haptic master

    Science.gov (United States)

    Hwang, Yong-Hoon; Cha, Seung-Woo; Kang, Seok-Rae; Choi, Seung-Bok

    2017-04-01

    In this study, a 7-DOF slave robot integrated with the haptic master is designed and its dynamic motion is controlled. The haptic master is made using a controllable magneto-rheological (MR) clutch and brake and it provides the surgeon with a sense of touch by using both kinetic and kinesthetic information. Due to the size constraint of the slave robot, a wire actuating is adopted to make the desired motion of the end-effector which has 3-DOF instead of a conventional direct-driven motor. Another motions of the link parts that have 4-DOF use direct-driven motor. In total system, for working as a haptic device, the haptic master need to receive the information of repulsive forces applied on the slave robot. Therefore, repulsive forces on the end-effector are sensed by using three uniaxial torque transducer inserted in the wire actuating system and another repulsive forces applied on link part are sensed by using 6-axis transducer that is able to sense forces and torques. Using another 6-axis transducer, verify the reliability of force information on final end of slave robot. Lastly, integrated with a MR haptic master, psycho-physical test is conducted by different operators who can feel the different repulsive force or torque generated from the haptic master which is equivalent to the force or torque occurred on the end-effector to demonstrate the effectiveness of the proposed system.

  2. A Study on Immersion and Presence of a Portable Hand Haptic System for Immersive Virtual Reality

    Science.gov (United States)

    Kim, Mingyu; Jeon, Changyu; Kim, Jinmo

    2017-01-01

    This paper proposes a portable hand haptic system using Leap Motion as a haptic interface that can be used in various virtual reality (VR) applications. The proposed hand haptic system was designed as an Arduino-based sensor architecture to enable a variety of tactile senses at low cost, and is also equipped with a portable wristband. As a haptic system designed for tactile feedback, the proposed system first identifies the left and right hands and then sends tactile senses (vibration and heat) to each fingertip (thumb and index finger). It is incorporated into a wearable band-type system, making its use easy and convenient. Next, hand motion is accurately captured using the sensor of the hand tracking system and is used for virtual object control, thus achieving interaction that enhances immersion. A VR application was designed with the purpose of testing the immersion and presence aspects of the proposed system. Lastly, technical and statistical tests were carried out to assess whether the proposed haptic system can provide a new immersive presence to users. According to the results of the presence questionnaire and the simulator sickness questionnaire, we confirmed that the proposed hand haptic system, in comparison to the existing interaction that uses only the hand tracking system, provided greater presence and a more immersive environment in the virtual reality. PMID:28513545

  3. Design of a 4-DOF MR haptic master for application to robot surgery: virtual environment work

    International Nuclear Information System (INIS)

    Oh, Jong-Seok; Choi, Seung-Hyun; Choi, Seung-Bok

    2014-01-01

    This paper presents the design and control performance of a novel type of 4-degrees-of-freedom (4-DOF) haptic master in cyberspace for a robot-assisted minimally invasive surgery (RMIS) application. By using a controllable magnetorheological (MR) fluid, the proposed haptic master can have a feedback function for a surgical robot. Due to the difficulty in utilizing real human organs in the experiment, the cyberspace that features the virtual object is constructed to evaluate the performance of the haptic master. In order to realize the cyberspace, a volumetric deformable object is represented by a shape-retaining chain-linked (S-chain) model, which is a fast volumetric model and is suitable for real-time applications. In the haptic architecture for an RMIS application, the desired torque and position induced from the virtual object of the cyberspace and the haptic master of real space are transferred to each other. In order to validate the superiority of the proposed master and volumetric model, a tracking control experiment is implemented with a nonhomogenous volumetric cubic object to demonstrate that the proposed model can be utilized in real-time haptic rendering architecture. A proportional-integral-derivative (PID) controller is then designed and empirically implemented to accomplish the desired torque trajectories. It has been verified from the experiment that tracking the control performance for torque trajectories from a virtual slave can be successfully achieved. (paper)

  4. HAPTIC LOCATION IN PSEUDOPHAKIC EYES AND NONINFECTIOUS POSTOPERATIVE INFLAMMATION- A PROSPECTIVE STUDY

    Directory of Open Access Journals (Sweden)

    Vinod Kumar Baranwal

    2017-01-01

    Full Text Available BACKGROUND Postoperative noninfectious inflammation after cataract surgery, which can be persistent, remains an undesirable consequence despite many advances in surgical techniques. This ocular inflammation after cataract surgery presents ophthalmologists with a treatment dilemma. The aim of the study was to evaluate and correlate the IOL haptic location and the presence of noninfectious postoperative inflammation in pseudophakic eyes using Ultrasound Biomicroscopy (UBM. MATERIALS AND METHODS In this prospective study, 80 eyes of 80 cataract patients underwent SICS with 6 mm optic non-foldable PCIOL implantation. Post surgery, an examination protocol was followed wherein the patients were assessed by slit-lamp examination on day 1, 2, 7, 14 and 30 for flare and cells. A UBM examination was performed on day 30 for locating the IOL haptic position. Finally, the postoperative inflammation was correlated with IOL haptic position. RESULTS The results showed that IOL haptic position outside the capsular bag significantly increased the amount and duration of postoperative inflammation. CONCLUSION Haptic position outside the bag increases the incidence and duration of postoperative inflammation significantly. In patients undergoing SICS, the aim should be a large continuous curvilinear capsulorhexis within the bag implantation of IOL. UBM examination on day 30 after surgery to know position of IOL haptics outside the bag will be helpful in decreasing apprehension of operating surgeon and suggesting prolonged need of steroids in cases having more than expected postoperative inflammation.

  5. Role of curvatures in determining the characteristics of a string vibrating against a doubly curved obstacle

    Science.gov (United States)

    Singh, Harkirat; Wahi, Pankaj

    2017-08-01

    The motion of a string in the presence of a doubly curved obstacle is investigated. A mathematical model has been developed for a general shape of the obstacle. However, detailed analysis has been performed for a shape relevant to the Indian stringed musical instruments like Tanpura and Sitar. In particular, we explore the effect of obstacle's curvature in the plane perpendicular to the string axis on its motion. This geometrical feature of the obstacle introduces a coupling between motions in mutually perpendicular directions over and above the coupling due to the stretching nonlinearity. We find that only one planar motion is possible for our system. Small amplitude planar motions are stable to perturbations in the perpendicular direction resulting in non-whirling motions while large amplitude oscillations lead to whirling motions. The critical amplitude of oscillations, across which there is a transition in the qualitative behavior of the non-planar trajectories, is determined using Floquet theory. Our analysis reveals that a small obstacle curvature in a direction perpendicular to the string axis leads to a considerable reduction in the critical amplitudes required for initiation of whirling motions. Hence, this obstacle curvature has a destabilizing effect on the planar motions in contrast to the curvature along the string axis which stabilizes planar motions.

  6. Comprehensive Use of Curvature for Robust and Accurate Online Surface Reconstruction.

    Science.gov (United States)

    Lefloch, Damien; Kluge, Markus; Sarbolandi, Hamed; Weyrich, Tim; Kolb, Andreas

    2017-12-01

    Interactive real-time scene acquisition from hand-held depth cameras has recently developed much momentum, enabling applications in ad-hoc object acquisition, augmented reality and other fields. A key challenge to online reconstruction remains error accumulation in the reconstructed camera trajectory, due to drift-inducing instabilities in the range scan alignments of the underlying iterative-closest-point (ICP) algorithm. Various strategies have been proposed to mitigate that drift, including SIFT-based pre-alignment, color-based weighting of ICP pairs, stronger weighting of edge features, and so on. In our work, we focus on surface curvature as a feature that is detectable on range scans alone and hence does not depend on accurate multi-sensor alignment. In contrast to previous work that took curvature into consideration, however, we treat curvature as an independent quantity that we consistently incorporate into every stage of the real-time reconstruction pipeline, including densely curvature-weighted ICP, range image fusion, local surface reconstruction, and rendering. Using multiple benchmark sequences, and in direct comparison to other state-of-the-art online acquisition systems, we show that our approach significantly reduces drift, both when analyzing individual pipeline stages in isolation, as well as seen across the online reconstruction pipeline as a whole.

  7. Curvature effect on nuclear 'pasta': Is it helpful for gyroid appearance?

    International Nuclear Information System (INIS)

    Nakazato, Ken'ichiro; Iida, Kei; Oyamatsu, Kazuhiro

    2011-01-01

    In supernova cores and neutron star crusts, nuclei are thought to deform to rodlike and slablike shapes, which are often called nuclear pasta. We study the equilibrium properties of the nuclear pasta by using a liquid-drop model with curvature corrections. It is confirmed that the curvature effect acts to lower the transition densities between different shapes. We also examine the gyroid structure, which was recently suggested as a different type of nuclear pasta by analogy with the polymer systems. The gyroid structure investigated in this paper is approximately formulated as an extension of the periodic minimal surface whose mean curvature vanishes. In contrast to our expectations, we find, from the present approximate formulation, that the curvature corrections act to slightly disfavor the appearance of the gyroid structure. By comparing the energy corrections in the gyroid phase and the hypothetical phases composed of d-dimensional spheres, where d is a general dimensionality, we show that the gyroid is unlikely to belong to a family of the generalized dimensional spheres.

  8. Curvature correction of retinal OCTs using graph-based geometry detection

    Science.gov (United States)

    Kafieh, Raheleh; Rabbani, Hossein; Abramoff, Michael D.; Sonka, Milan

    2013-05-01

    In this paper, we present a new algorithm as an enhancement and preprocessing step for acquired optical coherence tomography (OCT) images of the retina. The proposed method is composed of two steps, first of which is a denoising algorithm with wavelet diffusion based on a circular symmetric Laplacian model, and the second part can be described in terms of graph-based geometry detection and curvature correction according to the hyper-reflective complex layer in the retina. The proposed denoising algorithm showed an improvement of contrast-to-noise ratio from 0.89 to 1.49 and an increase of signal-to-noise ratio (OCT image SNR) from 18.27 to 30.43 dB. By applying the proposed method for estimation of the interpolated curve using a full automatic method, the mean ± SD unsigned border positioning error was calculated for normal and abnormal cases. The error values of 2.19 ± 1.25 and 8.53 ± 3.76 µm were detected for 200 randomly selected slices without pathological curvature and 50 randomly selected slices with pathological curvature, respectively. The important aspect of this algorithm is its ability in detection of curvature in strongly pathological images that surpasses previously introduced methods; the method is also fast, compared to the relatively low speed of similar methods.

  9. Curvature correction of retinal OCTs using graph-based geometry detection

    International Nuclear Information System (INIS)

    Kafieh, Raheleh; Rabbani, Hossein; Abramoff, Michael D; Sonka, Milan

    2013-01-01

    In this paper, we present a new algorithm as an enhancement and preprocessing step for acquired optical coherence tomography (OCT) images of the retina. The proposed method is composed of two steps, first of which is a denoising algorithm with wavelet diffusion based on a circular symmetric Laplacian model, and the second part can be described in terms of graph-based geometry detection and curvature correction according to the hyper-reflective complex layer in the retina. The proposed denoising algorithm showed an improvement of contrast-to-noise ratio from 0.89 to 1.49 and an increase of signal-to-noise ratio (OCT image SNR) from 18.27 to 30.43 dB. By applying the proposed method for estimation of the interpolated curve using a full automatic method, the mean ± SD unsigned border positioning error was calculated for normal and abnormal cases. The error values of 2.19 ± 1.25 and 8.53 ± 3.76 µm were detected for 200 randomly selected slices without pathological curvature and 50 randomly selected slices with pathological curvature, respectively. The important aspect of this algorithm is its ability in detection of curvature in strongly pathological images that surpasses previously introduced methods; the method is also fast, compared to the relatively low speed of similar methods. (paper)

  10. Polarized curvature radiation in pulsar magnetosphere

    Science.gov (United States)

    Wang, P. F.; Wang, C.; Han, J. L.

    2014-07-01

    The propagation of polarized emission in pulsar magnetosphere is investigated in this paper. The polarized waves are generated through curvature radiation from the relativistic particles streaming along curved magnetic field lines and corotating with the pulsar magnetosphere. Within the 1/γ emission cone, the waves can be divided into two natural wave-mode components, the ordinary (O) mode and the extraordinary (X) mode, with comparable intensities. Both components propagate separately in magnetosphere, and are aligned within the cone by adiabatic walking. The refraction of O mode makes the two components separated and incoherent. The detectable emission at a given height and a given rotation phase consists of incoherent X-mode and O-mode components coming from discrete emission regions. For four particle-density models in the form of uniformity, cone, core and patches, we calculate the intensities for each mode numerically within the entire pulsar beam. If the corotation of relativistic particles with magnetosphere is not considered, the intensity distributions for the X-mode and O-mode components are quite similar within the pulsar beam, which causes serious depolarization. However, if the corotation of relativistic particles is considered, the intensity distributions of the two modes are very different, and the net polarization of outcoming emission should be significant. Our numerical results are compared with observations, and can naturally explain the orthogonal polarization modes of some pulsars. Strong linear polarizations of some parts of pulsar profile can be reproduced by curvature radiation and subsequent propagation effect.

  11. Emergent gravity in spaces of constant curvature

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, Orlando; Haddad, Matthew [Department of Physics, University of Miami,1320 Campo Sano Ave, Coral Gables, FL 33146 (United States)

    2017-03-07

    In physical theories where the energy (action) is localized near a submanifold of a constant curvature space, there is a universal expression for the energy (or the action). We derive a multipole expansion for the energy that has a finite number of terms, and depends on intrinsic geometric invariants of the submanifold and extrinsic invariants of the embedding of the submanifold. This is the second of a pair of articles in which we try to develop a theory of emergent gravity arising from the embedding of a submanifold into an ambient space equipped with a quantum field theory. Our theoretical method requires a generalization of a formula due to by Hermann Weyl. While the first paper discussed the framework in Euclidean (Minkowski) space, here we discuss how this framework generalizes to spaces of constant sectional curvature. We focus primarily on anti de Sitter space. We then discuss how such a theory can give rise to a cosmological constant and Planck mass that are within reasonable bounds of the experimental values.

  12. Modeling and Control of Collaborative Robot System using Haptic Feedback

    Directory of Open Access Journals (Sweden)

    Vivekananda Shanmuganatha

    2017-08-01

    Full Text Available When two robot systems can share understanding using any agreed knowledge, within the constraints of the system’s communication protocol, the approach may lead to a common improvement. This has persuaded numerous new research inquiries in human-robot collaboration. We have built up a framework prepared to do independent following and performing table-best protest object manipulation with humans and we have actualized two different activity models to trigger robot activities. The idea here is to explore collaborative systems and to build up a plan for them to work in a collaborative environment which has many benefits to a single more complex system. In the paper, two robots that cooperate among themselves are constructed. The participation linking the two robotic arms, the torque required and parameters are analyzed. Thus the purpose of this paper is to demonstrate a modular robot system which can serve as a base on aspects of robotics in collaborative robots using haptics.

  13. Research on a haptic sensor made using MCF conductive rubber

    International Nuclear Information System (INIS)

    Zheng Yaoyang; Shimada, Kunio

    2008-01-01

    To provide a new composite material having a high electrical sensitivity in the fields of robotics and sensing, a magnetic rubber having network-like magnetic clusters was developed by utilizing a magnetic compound fluid (MCF). MCF rubber with small deformations can provide an effective sensor. In this paper, we report many experiments in which changes of the MCF rubber's resistance were observed when the rubber was compressed and a deformation was generated; we then made a trial haptic sensor using the MCF conductive rubber and performed many experiments to observe changes of the electrical resistance of the sensor. The results of experiments showed that the proposed sensor made with MCF conductive rubber is useful for sensing small amounts of pressure or small deformations

  14. Research on a haptic sensor made using MCF conductive rubber

    Energy Technology Data Exchange (ETDEWEB)

    Zheng Yaoyang; Shimada, Kunio [Faculty of Symbiotic Systems Science Fukushima University, 1 Kanayakawa, Fukushima 960-1296 (Japan)], E-mail: tei@sss.fukushima-u.ac.jp, E-mail: shimadakun@sss.fukushima-u.ac.jp

    2008-05-21

    To provide a new composite material having a high electrical sensitivity in the fields of robotics and sensing, a magnetic rubber having network-like magnetic clusters was developed by utilizing a magnetic compound fluid (MCF). MCF rubber with small deformations can provide an effective sensor. In this paper, we report many experiments in which changes of the MCF rubber's resistance were observed when the rubber was compressed and a deformation was generated; we then made a trial haptic sensor using the MCF conductive rubber and performed many experiments to observe changes of the electrical resistance of the sensor. The results of experiments showed that the proposed sensor made with MCF conductive rubber is useful for sensing small amounts of pressure or small deformations.

  15. Research on a haptic sensor made using MCF conductive rubber

    Science.gov (United States)

    Zheng, Yaoyang; Shimada, Kunio

    2008-05-01

    To provide a new composite material having a high electrical sensitivity in the fields of robotics and sensing, a magnetic rubber having network-like magnetic clusters was developed by utilizing a magnetic compound fluid (MCF). MCF rubber with small deformations can provide an effective sensor. In this paper, we report many experiments in which changes of the MCF rubber's resistance were observed when the rubber was compressed and a deformation was generated; we then made a trial haptic sensor using the MCF conductive rubber and performed many experiments to observe changes of the electrical resistance of the sensor. The results of experiments showed that the proposed sensor made with MCF conductive rubber is useful for sensing small amounts of pressure or small deformations.

  16. Advanced haptic sensor for measuring human skin conditions

    Science.gov (United States)

    Tsuchimi, Daisuke; Okuyama, Takeshi; Tanaka, Mami

    2010-01-01

    This paper is concerned with the development of a tactile sensor using PVDF (Polyvinylidene Fluoride) film as a sensory receptor of the sensor to evaluate softness, smoothness, and stickiness of human skin. Tactile sense is the most important sense in the sensation receptor of the human body along with eyesight, and we can examine skin condition quickly using these sense. But, its subjectivity and ambiguity make it difficult to quantify skin conditions. Therefore, development of measurement device which can evaluate skin conditions easily and objectively is demanded by dermatologists, cosmetic industries, and so on. In this paper, an advanced haptic sensor system that can measure multiple information of skin condition in various parts of human body is developed. The applications of the sensor system to evaluate softness, smoothness, and stickiness of skin are investigated through two experiments.

  17. [Methods of resolution for haptic assistance during catheterization].

    Science.gov (United States)

    Kern, T A; Herrmann, J; Klages, S; Meiss, T; Werthschützky, R

    2005-01-01

    During catheterization navigation within the patient is mainly dependent on a live x-ray image on the screen. Although methods for 3D visualisation and remote navigation of the catheter are discussed and tested still precise positioning is merely the result of intense training and a high skill and level of training of the performing surgeon. This article refers to a system which can be considered as an add-on for existing procedures of catheterization. It compromises of a miniaturised force sensor located at the tip of guide-wires whose prototype is shown here. The measured forces will be presented to the surgeon amplified by an external actuator described in this article. As a result a haptic perception of the forces between the tip of the guide-wire and the vessels walls will be available and enable the surgeon to gain an impression which is comparable to palpation of living vessels from the inside

  18. A 3-DOF haptic master device for minimally invasive surgery

    Science.gov (United States)

    Nguyen, Phuong-Bac; Oh, Jong-Seok; Choi, Seung-Bok

    2012-04-01

    This paper introduces a novel 3-DOF haptic master device for minimally invasive surgery featuring magneto-rheological (MR) fluid. It consists of three rotational motions. These motions are constituted by two bi-directional MR (BMR) plus one conventional MR brakes. The BMR brake used in the system possesses a salient advantage that its range of braking torque varies from negative to positive values. Therefore, the device is expected to be able sense in a wide environment from very soft tissues to bones. In this paper, overall of the design of the device is presented from idea, modeling, optimal design, manufacturing to control of the device. Moreover, experimental investigation is undertaken to validate the effectiveness of the device.

  19. Dynamic Investigation Test-rig on hAptics (DITA)

    International Nuclear Information System (INIS)

    Cannella, F; Olivieri, E; Caldwell, D G; Scalise, L; Memeo, M

    2013-01-01

    Research on tactile sensitivity has been conducted since the last century and many devices have been proposed to study in detail this sense through experimental tests. The sense of touch is essential in every-day life of human beings, but it can also play a fundamental role for the assessment of some neurological disabilities and pathologies. In fact, the level of tactile perception can provide information on the health state of the nervous system. In this paper, authors propose the design and development of a novel test apparatus, named DITA (Dynamic Investigation Test-rig on hAptics), aiming to provide the measurement of the tactile sensitivity trough the determination of the Just Noticeable Difference (JND) curve of a subject. The paper reports the solution adopted for the system design and the results obtained on the set of experiments carried out on volunteers

  20. From conditioning shampoo to nanomechanics and haptics of human hair.

    Science.gov (United States)

    Wood, Claudia; Sugiharto, Albert Budiman; Max, Eva; Fery, Andreas

    2011-01-01

    Shampoo treatment and hair conditioning have a direct impact on our wellbeing via properties like combability and haptic perception of hair. Therefore, systematic investigations leading to quality improvement of hair care products are of major interest. The aim of our work is a better understanding of complex testing and the correlation with quantitative parameters. The motivation for the development of physical testing methods for hair feel relates to the fact that an ingredient supplier like BASF can only find new, so far not yet toxicologically approved chemistries for hair cosmetics, if an in-vitro method exists.In this work, the effects of different shampoo treatments with conditioning polymers are investigated. The employed physical test method, dry friction measurements and AFM observe friction phenomena on a macroscopic as well as on a nanoscale directly on hair. They are an approach to complement sensoric evaluation with an objective in-vitro method.

  1. A remote instruction system empowered by tightly shared haptic sensation

    Science.gov (United States)

    Nishino, Hiroaki; Yamaguchi, Akira; Kagawa, Tsuneo; Utsumiya, Kouichi

    2007-09-01

    We present a system to realize an on-line instruction environment among physically separated participants based on a multi-modal communication strategy. In addition to visual and acoustic information, commonly used communication modalities in network environments, our system provides a haptic channel to intuitively conveying partners' sense of touch. The human touch sensation, however, is very sensitive for delays and jitters in the networked virtual reality (NVR) systems. Therefore, a method to compensate for such negative factors needs to be provided. We show an NVR architecture to implement a basic framework that can be shared by various applications and effectively deals with the problems. We take a hybrid approach to implement both data consistency by client-server and scalability by peer-to-peer models. As an application system built on the proposed architecture, a remote instruction system targeted at teaching handwritten characters and line patterns on a Korea-Japan high-speed research network also is mentioned.

  2. Haptics Application in Dentistry: Is the Time Poised Yet?

    Directory of Open Access Journals (Sweden)

    Srinivas Sulugodu Ramachandra

    2011-01-01

    Full Text Available The essence of dental education is not only to impart knowledge but also to equip an aspiring clinician with all the para-phernalia to face most clinical situations if not all. What be-comes important here is the requirement that a student be not only observant but also have a precise idea of what a lesion or a surface should feel like under an instrument. No matter how far we have come in terms of pathogenesis and treatment of diseases of the oral cavity, there is still no one good way to teach a student about the tactile sense, be it while de-tecting calculus/caries or placing the incisions or detecting the smoothness of a restoration. Most often than not students learn these by a trial and error method. A not-so-recent development called Haptics may well be the answer to this predicament, at least in the near future. The concept which is extensively in use and indis-pensable in other fields like aviation, telecommunication etc is now making inroads into dentistry. It is essentially software which brings in the idea of giving the feedback response to applied force, be it simple exploration of caries or the fine pressure applied in placing an incision or an array of other areas/situations in dentistry where fine tactile sense becomes a prerequisite for intelligent diagnoses or cutting edge treatment procedures. The following write-up is an attempt to throw light on this new technology and the impact it may have on pre-clinical teaching in dentistry. The advantages, disadvantages be-tween manikin based dental simulators and haptics based dental simulators are also pre-sented.

  3. Graphic and haptic simulation for transvaginal cholecystectomy training in NOTES.

    Science.gov (United States)

    Pan, Jun J; Ahn, Woojin; Dargar, Saurabh; Halic, Tansel; Li, Bai C; Sankaranarayanan, Ganesh; Roberts, Kurt; Schwaitzberg, Steven; De, Suvranu

    2016-04-01

    Natural Orifice Transluminal Endoscopic Surgery (NOTES) provides an emerging surgical technique which usually needs a long learning curve for surgeons. Virtual reality (VR) medical simulators with vision and haptic feedback can usually offer an efficient and cost-effective alternative without risk to the traditional training approaches. Under this motivation, we developed the first virtual reality simulator for transvaginal cholecystectomy in NOTES (VTEST™). This VR-based surgical simulator aims to simulate the hybrid NOTES of cholecystectomy. We use a 6DOF haptic device and a tracking sensor to construct the core hardware component of simulator. For software, an innovative approach based on the inner-spheres is presented to deform the organs in real time. To handle the frequent collision between soft tissue and surgical instruments, an adaptive collision detection method based on GPU is designed and implemented. To give a realistic visual performance of gallbladder fat tissue removal by cautery hook, a multi-layer hexahedral model is presented to simulate the electric dissection of fat tissue. From the experimental results, trainees can operate in real time with high degree of stability and fidelity. A preliminary study was also performed to evaluate the realism and the usefulness of this hybrid NOTES simulator. This prototyped simulation system has been verified by surgeons through a pilot study. Some items of its visual performance and the utility were rated fairly high by the participants during testing. It exhibits the potential to improve the surgical skills of trainee and effectively shorten their learning curve. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Lecture notes on mean curvature flow, barriers and singular perturbations

    CERN Document Server

    Bellettini, Giovanni

    2013-01-01

    The aim of the book is to study some aspects of geometric evolutions, such as mean curvature flow and anisotropic mean curvature flow of hypersurfaces. We analyze the origin of such flows and their geometric and variational nature. Some of the most important aspects of mean curvature flow are described, such as the comparison principle and its use in the definition of suitable weak solutions. The anisotropic evolutions, which can be considered as a generalization of mean curvature flow, are studied from the view point of Finsler geometry. Concerning singular perturbations, we discuss the convergence of the Allen–Cahn (or Ginsburg–Landau) type equations to (possibly anisotropic) mean curvature flow before the onset of singularities in the limit problem. We study such kinds of asymptotic problems also in the static case, showing convergence to prescribed curvature-type problems.

  5. The curvature calculation mechanism based on simple cell model.

    Science.gov (United States)

    Yu, Haiyang; Fan, Xingyu; Song, Aiqi

    2017-07-20

    A conclusion has not yet been reached on how exactly the human visual system detects curvature. This paper demonstrates how orientation-selective simple cells can be used to construct curvature-detecting neural units. Through fixed arrangements, multiple plurality cells were constructed to simulate curvature cells with a proportional output to their curvature. In addition, this paper offers a solution to the problem of narrow detection range under fixed resolution by selecting an output value under multiple resolution. Curvature cells can be treated as concrete models of an end-stopped mechanism, and they can be used to further understand "curvature-selective" characteristics and to explain basic psychophysical findings and perceptual phenomena in current studies.

  6. On Riemannian manifolds (Mn, g) of quasi-constant curvature

    International Nuclear Information System (INIS)

    Rahman, M.S.

    1995-07-01

    A Riemannian manifold (M n , g) of quasi-constant curvature is defined. It is shown that an (M n , g) in association with other class of manifolds gives rise, under certain conditions, to a manifold of quasi-constant curvature. Some observations on how a manifold of quasi-constant curvature accounts for a pseudo Ricci-symmetric manifold and quasi-umbilical hypersurface are made. (author). 10 refs

  7. Statistical mechanics of paths with curvature dependent action

    International Nuclear Information System (INIS)

    Ambjoern, J.; Durhuus, B.; Jonsson, T.

    1987-01-01

    We analyze the scaling limit of discretized random paths with curvature dependent action. For finite values of the curvature coupling constant the theory belongs to the universality class of simple random walk. It is possible to define a non-trivial scaling limit if the curvature coupling tends to infinity. We compute exactly the two point function in this limit and discuss the relevance of our results for random surfaces and string theories. (orig.)

  8. Evolution of the curvature perturbations during warm inflation

    International Nuclear Information System (INIS)

    Matsuda, Tomohiro

    2009-01-01

    This paper considers warm inflation as an interesting application of multi-field inflation. Delta-N formalism is used for the calculation of the evolution of the curvature perturbations during warm inflation. Although the perturbations considered in this paper are decaying after the horizon exit, the corrections to the curvature perturbations sourced by these perturbations can remain and dominate the curvature perturbations at large scales. In addition to the typical evolution of the curvature perturbations, inhomogeneous diffusion rate is considered for warm inflation, which may lead to significant non-Gaussianity of the spectrum

  9. 3D face recognition with asymptotic cones based principal curvatures

    KAUST Repository

    Tang, Yinhang; Sun, Xiang; Huang, Di; Morvan, Jean-Marie; Wang, Yunhong; Chen, Liming

    2015-01-01

    The classical curvatures of smooth surfaces (Gaussian, mean and principal curvatures) have been widely used in 3D face recognition (FR). However, facial surfaces resulting from 3D sensors are discrete meshes. In this paper, we present a general framework and define three principal curvatures on discrete surfaces for the purpose of 3D FR. These principal curvatures are derived from the construction of asymptotic cones associated to any Borel subset of the discrete surface. They describe the local geometry of the underlying mesh. First two of them correspond to the classical principal curvatures in the smooth case. We isolate the third principal curvature that carries out meaningful geometric shape information. The three principal curvatures in different Borel subsets scales give multi-scale local facial surface descriptors. We combine the proposed principal curvatures with the LNP-based facial descriptor and SRC for recognition. The identification and verification experiments demonstrate the practicability and accuracy of the third principal curvature and the fusion of multi-scale Borel subset descriptors on 3D face from FRGC v2.0.

  10. Robust estimation of adaptive tensors of curvature by tensor voting.

    Science.gov (United States)

    Tong, Wai-Shun; Tang, Chi-Keung

    2005-03-01

    Although curvature estimation from a given mesh or regularly sampled point set is a well-studied problem, it is still challenging when the input consists of a cloud of unstructured points corrupted by misalignment error and outlier noise. Such input is ubiquitous in computer vision. In this paper, we propose a three-pass tensor voting algorithm to robustly estimate curvature tensors, from which accurate principal curvatures and directions can be calculated. Our quantitative estimation is an improvement over the previous two-pass algorithm, where only qualitative curvature estimation (sign of Gaussian curvature) is performed. To overcome misalignment errors, our improved method automatically corrects input point locations at subvoxel precision, which also rejects outliers that are uncorrectable. To adapt to different scales locally, we define the RadiusHit of a curvature tensor to quantify estimation accuracy and applicability. Our curvature estimation algorithm has been proven with detailed quantitative experiments, performing better in a variety of standard error metrics (percentage error in curvature magnitudes, absolute angle difference in curvature direction) in the presence of a large amount of misalignment noise.

  11. 3D face recognition with asymptotic cones based principal curvatures

    KAUST Repository

    Tang, Yinhang

    2015-05-01

    The classical curvatures of smooth surfaces (Gaussian, mean and principal curvatures) have been widely used in 3D face recognition (FR). However, facial surfaces resulting from 3D sensors are discrete meshes. In this paper, we present a general framework and define three principal curvatures on discrete surfaces for the purpose of 3D FR. These principal curvatures are derived from the construction of asymptotic cones associated to any Borel subset of the discrete surface. They describe the local geometry of the underlying mesh. First two of them correspond to the classical principal curvatures in the smooth case. We isolate the third principal curvature that carries out meaningful geometric shape information. The three principal curvatures in different Borel subsets scales give multi-scale local facial surface descriptors. We combine the proposed principal curvatures with the LNP-based facial descriptor and SRC for recognition. The identification and verification experiments demonstrate the practicability and accuracy of the third principal curvature and the fusion of multi-scale Borel subset descriptors on 3D face from FRGC v2.0.

  12. Cholera toxin B subunit induces local curvature on lipid bilayers

    DEFF Research Database (Denmark)

    Pezeshkian, Weria; Nåbo, Lina J.; Ipsen, John H.

    2017-01-01

    B induces a local membrane curvature that is essential for its clathrin-independent uptake. Using all-atom molecular dynamics, we show that CTxB induces local curvature, with the radius of curvature around 36 nm. The main feature of the CTxB molecular structure that causes membrane bending is the protruding...... alpha helices in the middle of the protein. Our study points to a generic protein design principle for generating local membrane curvature through specific binding to their lipid anchors....

  13. Hair curvature: a natural dialectic and review.

    Science.gov (United States)

    Nissimov, Joseph N; Das Chaudhuri, Asit Baran

    2014-08-01

    Although hair forms (straight, curly, wavy, etc.) are present in apparently infinite variations, each fibre can be reduced to a finite sequence of tandem segments of just three types: straight, bent/curly, or twisted. Hair forms can thus be regarded as resulting from genetic pathways that induce, reverse or modulate these basic curvature modes. However, physical interconversions between twists and curls demonstrate that strict one-to-one correspondences between them and their genetic causes do not exist. Current hair-curvature theories do not distinguish between bending and twisting mechanisms. We here introduce a multiple papillary centres (MPC) model which is particularly suitable to explain twisting. The model combines previously known features of hair cross-sectional morphology with partially/completely separated dermal papillae within single follicles, and requires such papillae to induce differential growth rates of hair cortical material in their immediate neighbourhoods. The MPC model can further help to explain other, poorly understood, aspects of hair growth and morphology. Separate bending and twisting mechanisms would be preferentially affected at the major or minor ellipsoidal sides of fibres, respectively, and together they exhaust the possibilities for influencing hair-form phenotypes. As such they suggest dialectic for hair-curvature development. We define a natural-dialectic (ND) which could take advantage of speculative aspects of dialectic, but would verify its input data and results by experimental methods. We use this as a top-down approach to first define routes by which hair bending or twisting may be brought about and then review evidence in support of such routes. In particular we consider the wingless (Wnt) and mammalian target of rapamycin (mTOR) pathways as paradigm pathways for molecular hair bending and twisting mechanisms, respectively. In addition to the Wnt canonical pathway, the Wnt/Ca(2+) and planar cell polarity (PCP) pathways

  14. Effects of kinesthetic haptic feedback on standing stability of young healthy subjects and stroke patients.

    Science.gov (United States)

    Afzal, Muhammad Raheel; Byun, Ha-Young; Oh, Min-Kyun; Yoon, Jungwon

    2015-03-13

    Haptic control is a useful therapeutic option in rehabilitation featuring virtual reality interaction. As with visual and vibrotactile biofeedback, kinesthetic haptic feedback may assist in postural control, and can achieve balance control. Kinesthetic haptic feedback in terms of body sway can be delivered via a commercially available haptic device and can enhance the balance stability of both young healthy subjects and stroke patients. Our system features a waist-attached smartphone, software running on a computer (PC), and a dedicated Phantom Omni® device. Young healthy participants performed balance tasks after assumption of each of four distinct postures for 30 s (one foot on the ground; the Tandem Romberg stance; one foot on foam; and the Tandem Romberg stance on foam) with eyes closed. Patient eyes were not closed and assumption of the Romberg stance (only) was tested during a balance task 25 s in duration. An Android application running continuously on the smartphone sent mediolateral (ML) and anteroposterior (AP) tilt angles to a PC, which generated kinesthetic haptic feedback via Phantom Omni®. A total of 16 subjects, 8 of whom were young healthy and 8 of whom had suffered stroke, participated in the study. Post-experiment data analysis was performed using MATLAB®. Mean Velocity Displacement (MVD), Planar Deviation (PD), Mediolateral Trajectory (MLT) and Anteroposterior Trajectory (APT) parameters were analyzed to measure reduction in body sway. Our kinesthetic haptic feedback system was effective to reduce postural sway in young healthy subjects regardless of posture and the condition of the substrate (the ground) and to improve MVD and PD in stroke patients who assumed the Romberg stance. Analysis of Variance (ANOVA) revealed that kinesthetic haptic feedback significantly reduced body sway in both categories of subjects. Kinesthetic haptic feedback can be implemented using a commercial haptic device and a smartphone. Intuitive balance cues were

  15. Hawking temperature of constant curvature black holes

    International Nuclear Information System (INIS)

    Cai Ronggen; Myung, Yun Soo

    2011-01-01

    The constant curvature (CC) black holes are higher dimensional generalizations of Banados-Teitelboim-Zanelli black holes. It is known that these black holes have the unusual topology of M D-1 xS 1 , where D is the spacetime dimension and M D-1 stands for a conformal Minkowski spacetime in D-1 dimensions. The unusual topology and time-dependence for the exterior of these black holes cause some difficulties to derive their thermodynamic quantities. In this work, by using a globally embedding approach, we obtain the Hawking temperature of the CC black holes. We find that the Hawking temperature takes the same form when using both the static and global coordinates. Also, it is identical to the Gibbons-Hawking temperature of the boundary de Sitter spaces of these CC black holes.

  16. Differential geometry connections, curvature, and characteristic classes

    CERN Document Server

    Tu, Loring W

    2017-01-01

    This text presents a graduate-level introduction to differential geometry for mathematics and physics students. The exposition follows the historical development of the concepts of connection and curvature with the goal of explaining the Chern–Weil theory of characteristic classes on a principal bundle. Along the way we encounter some of the high points in the history of differential geometry, for example, Gauss' Theorema Egregium and the Gauss–Bonnet theorem. Exercises throughout the book test the reader’s understanding of the material and sometimes illustrate extensions of the theory. Initially, the prerequisites for the reader include a passing familiarity with manifolds. After the first chapter, it becomes necessary to understand and manipulate differential forms. A knowledge of de Rham cohomology is required for the last third of the text. Prerequisite material is contained in author's text An Introduction to Manifolds, and can be learned in one semester. For the benefit of the reader and to establ...

  17. Curvature radiation by bunches of particles

    International Nuclear Information System (INIS)

    Saggion, A.

    1975-01-01

    A bunch of relativistic particles moving on a curved trajectory is considered. The coherent emission of curvature radiation is described with particular regard to the role played by the 'shape' of the bunch as a function of its dimensions. It is found that the length of the bunch strongly affects the spectrum of the radiation emitted, with no effect on its polarization. For wavelengths shorter than the length of the bunch, the emitted intensity as a function of frequency shows recurrent maxima and minima, the height of the maxima being proportional to νsup(-5/3). The bunch dimensions perpendicular to the plane of the orbit affect both the spectral intensity and the polarization of the radiation. (orig./BJ) [de

  18. Natural curvature for manifest T-duality

    International Nuclear Information System (INIS)

    Poláček, Martin; Siegel, Warren

    2014-01-01

    We reformulate the manifestly T-dual description of the massless sector of the closed bosonic string, directly from the geometry associated with the (left and right) affine Lie algebra of the coset space Poincaré/Lorentz. This construction initially doubles not only the (spacetime) coordinates for translations but also those for Lorentz transformations (and their “dual”). As a result, the Lorentz connection couples directly to the string (as does the vielbein), rather than being introduced ad hoc to the covariant derivative as previously. This not only reproduces the old definition of T-dual torsion, but automatically gives a general, covariant definition of T-dual curvature (but still with some undetermined connections)

  19. Nonminimal coupling of perfect fluids to curvature

    International Nuclear Information System (INIS)

    Bertolami, Orfeu; Lobo, Francisco S. N.; Paramos, Jorge

    2008-01-01

    In this work, we consider different forms of relativistic perfect fluid Lagrangian densities that yield the same gravitational field equations in general relativity (GR). A particularly intriguing example is the case with couplings of the form [1+f 2 (R)]L m , where R is the scalar curvature, which induces an extra force that depends on the form of the Lagrangian density. It has been found that, considering the Lagrangian density L m =p, where p is the pressure, the extra-force vanishes. We argue that this is not the unique choice for the matter Lagrangian density, and that more natural forms for L m do not imply the vanishing of the extra force. Particular attention is paid to the impact on the classical equivalence between different Lagrangian descriptions of a perfect fluid.

  20. Topological photonic crystals with zero Berry curvature

    Science.gov (United States)

    Liu, Feng; Deng, Hai-Yao; Wakabayashi, Katsunori

    2018-02-01

    Topological photonic crystals are designed based on the concept of Zak's phase rather than the topological invariants such as the Chern number and spin Chern number, which rely on the existence of a nonvanishing Berry curvature. Our photonic crystals (PCs) are made of pure dielectrics and sit on a square lattice obeying the C4 v point-group symmetry. Two varieties of PCs are considered: one closely resembles the electronic two-dimensional Su-Schrieffer-Heeger model, and the other continues as an extension of this analogy. In both cases, the topological transitions are induced by adjusting the lattice constants. Topological edge modes (TEMs) are shown to exist within the nontrivial photonic band gaps on the termination of those PCs. The high efficiency of these TEMs transferring electromagnetic energy against several types of disorders has been demonstrated using the finite-element method.

  1. A Field Theory with Curvature and Anticurvature

    Directory of Open Access Journals (Sweden)

    M. I. Wanas

    2014-01-01

    Full Text Available The present work is an attempt to construct a unified field theory in a space with curvature and anticurvature, the PAP-space. The theory is derived from an action principle and a Lagrangian density using a symmetric linear parameterized connection. Three different methods are used to explore physical contents of the theory obtained. Poisson’s equations for both material and charge distributions are obtained, as special cases, from the field equations of the theory. The theory is a pure geometric one in the sense that material distribution, charge distribution, gravitational and electromagnetic potentials, and other physical quantities are defined in terms of pure geometric objects of the structure used. In the case of pure gravity in free space, the spherical symmetric solution of the field equations gives the Schwarzschild exterior field. The weak equivalence principle is respected only in the case of pure gravity in free space; otherwise it is violated.

  2. Performance evaluation of a robot-assisted catheter operating system with haptic feedback.

    Science.gov (United States)

    Song, Yu; Guo, Shuxiang; Yin, Xuanchun; Zhang, Linshuai; Hirata, Hideyuki; Ishihara, Hidenori; Tamiya, Takashi

    2018-06-20

    In this paper, a novel robot-assisted catheter operating system (RCOS) has been proposed as a method to reduce physical stress and X-ray exposure time to physicians during endovascular procedures. The unique design of this system allows the physician to apply conventional bedside catheterization skills (advance, retreat and rotate) to an input catheter, which is placed at the master side to control another patient catheter placed at the slave side. For this purpose, a magnetorheological (MR) fluids-based master haptic interface has been developed to measure the axial and radial motions of an input catheter, as well as to provide the haptic feedback to the physician during the operation. In order to achieve a quick response of the haptic force in the master haptic interface, a hall sensor-based closed-loop control strategy is employed. In slave side, a catheter manipulator is presented to deliver the patient catheter, according to position commands received from the master haptic interface. The contact forces between the patient catheter and blood vessel system can be measured by designed force sensor unit of catheter manipulator. Four levels of haptic force are provided to make the operator aware of the resistance encountered by the patient catheter during the insertion procedure. The catheter manipulator was evaluated for precision positioning. The time lag from the sensed motion to replicated motion is tested. To verify the efficacy of the proposed haptic feedback method, the evaluation experiments in vitro are carried out. The results demonstrate that the proposed system has the ability to enable decreasing the contact forces between the catheter and vasculature.

  3. Rapid processing of haptic cues for postural control in blind subjects.

    Science.gov (United States)

    Schieppati, Marco; Schmid, Monica; Sozzi, Stefania

    2014-07-01

    Vision and touch rapidly lead to postural stabilization in sighted subjects. Is touch-induced stabilization more rapid in blind than in sighted subjects, owing to cross-modal reorganization of function in the blind? We estimated the time-period elapsing from onset of availability of haptic support to onset of lateral stabilization in a group of early- and late-onset blinds. Eleven blind (age 39.4 years±11.7SD) and eleven sighted subjects (age 30.0 years±10.0SD), standing eyes closed with feet in tandem position, touched a pad with their index finger and withdrew the finger from the pad in sequence. EMG of postural muscles and displacement of centre of foot pressure were recorded. The task was repeated fifty times, to allow statistical evaluation of the latency of EMG and sway changes following the haptic shift. Steady-state sway (with or without contact with pad, no haptic shift) did not differ between blind and sighted. On adding the haptic stimulus, EMG and sway diminished in both groups, but at an earlier latency (by about 0.5 s) in the blinds (p blinds. When the haptic stimulus was withdrawn, both groups increased EMG and sway at equally short delays. Blinds are rapid in implementing adaptive postural modifications when granted an external haptic reference. Fast processing of the stabilizing haptic spatial-orientation cues may be favoured by cortical plasticity in blinds. These findings add new information to the field of sensory-guided dynamic control of equilibrium in man. Copyright © 2013 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  4. Training haptic stiffness discrimination: time course of learning with or without visual information and knowledge of results.

    Science.gov (United States)

    Teodorescu, Kinneret; Bouchigny, Sylvain; Korman, Maria

    2013-08-01

    In this study, we explored the time course of haptic stiffness discrimination learning and how it was affected by two experimental factors, the addition of visual information and/or knowledge of results (KR) during training. Stiffness perception may integrate both haptic and visual modalities. However, in many tasks, the visual field is typically occluded, forcing stiffness perception to be dependent exclusively on haptic information. No studies to date addressed the time course of haptic stiffness perceptual learning. Using a virtual environment (VE) haptic interface and a two-alternative forced-choice discrimination task, the haptic stiffness discrimination ability of 48 participants was tested across 2 days. Each day included two haptic test blocks separated by a training block Additional visual information and/or KR were manipulated between participants during training blocks. Practice repetitions alone induced significant improvement in haptic stiffness discrimination. Between days, accuracy was slightly improved, but decision time performance was deteriorated. The addition of visual information and/or KR had only temporary effects on decision time, without affecting the time course of haptic discrimination learning. Learning in haptic stiffness discrimination appears to evolve through at least two distinctive phases: A single training session resulted in both immediate and latent learning. This learning was not affected by the training manipulations inspected. Training skills in VE in spaced sessions can be beneficial for tasks in which haptic perception is critical, such as surgery procedures, when the visual field is occluded. However, training protocols for such tasks should account for low impact of multisensory information and KR.

  5. Differences between early-blind, late-blind, and blindfolded-sighted people in haptic spatial-configuration learning and resulting memory traces

    NARCIS (Netherlands)

    Postma, Albert; Zuidhoek, Sander; Noordzij, Matthijs L.; Kappers, Astrid M L

    2007-01-01

    The roles of visual and haptic experience in different aspects of haptic processing of objects in peripersonal space are examined. In three trials, early-blind, late-blind, and blindfoldedsighted individuals had to match ten shapes haptically to the cut-outs in a board as fast as possible. Both

  6. Contrast media

    International Nuclear Information System (INIS)

    Decazes, Ph.

    2004-01-01

    The Guerbet firm, which holds 69% of the capital on the contrast media for medical imagery, could sale about 20% of this capital in order to accelerate its development in the United States, one of its next market with the Japan. (O.M.)

  7. On harmonic curvatures of a Frenet curve in Lorentzian space

    International Nuclear Information System (INIS)

    Kuelahci, Mihriban; Bektas, Mehmet; Erguet, Mahmut

    2009-01-01

    In this paper, we consider curves of AW(k)-type, 1 ≤ k ≤ 3, in Lorentzian space. We give curvature conditions of these kind of curves. Furthermore, we study harmonic curvatures of curves of AW(k)-type. We investigate that under what conditions AW(k)-type curves are helix. Some related theorems and corollaries are also proved.

  8. The scalar curvature problem on the four dimensional half sphere

    CERN Document Server

    Ben-Ayed, M; El-Mehdi, K

    2003-01-01

    In this paper, we consider the problem of prescribing the scalar curvature under minimal boundary conditions on the standard four dimensional half sphere. We provide an Euler-Hopf type criterion for a given function to be a scalar curvature for some metric conformal to the standard one. Our proof involves the study of critical points at infinity of the associated variational problem.

  9. Statistical mechanics of surfaces with curvature dependent action

    International Nuclear Information System (INIS)

    Jonsson, T.

    1987-01-01

    We review recent results about discretized random surfaces whose action (energy) depends on the extrinsic curvature. The surface tension scales to zero at an appropriate critical point if the coupling constant of the curvature term is taken to infinity. At this critical point one expects to be able to construct a continuum theory of smooth surfaces. (orig.)

  10. Curvature of random walks and random polygons in confinement

    International Nuclear Information System (INIS)

    Diao, Y; Ernst, C; Montemayor, A; Ziegler, U

    2013-01-01

    The purpose of this paper is to study the curvature of equilateral random walks and polygons that are confined in a sphere. Curvature is one of several basic geometric properties that can be used to describe random walks and polygons. We show that confinement affects curvature quite strongly, and in the limit case where the confinement diameter equals the edge length the unconfined expected curvature value doubles from π/2 to π. To study curvature a simple model of an equilateral random walk in spherical confinement in dimensions 2 and 3 is introduced. For this simple model we derive explicit integral expressions for the expected value of the total curvature in both dimensions. These expressions are functions that depend only on the radius R of the confinement sphere. We then show that the values obtained by numeric integration of these expressions agrees with numerical average curvature estimates obtained from simulations of random walks. Finally, we compare the confinement effect on curvature of random walks with random polygons. (paper)

  11. Curvature collineations for the field of gravitational waves

    International Nuclear Information System (INIS)

    Singh, K.P.; Singh, Gulab

    1981-01-01

    It has been shown that the space-times formed from a plane-fronted gravity wave and from a plane sandwich wave with constant polarisation admit proper curvature collineation in general. The curvature collineation vectors have been determined explicitly. (author)

  12. Robust modal curvature features for identifying multiple damage in beams

    Science.gov (United States)

    Ostachowicz, Wiesław; Xu, Wei; Bai, Runbo; Radzieński, Maciej; Cao, Maosen

    2014-03-01

    Curvature mode shape is an effective feature for damage detection in beams. However, it is susceptible to measurement noise, easily impairing its advantage of sensitivity to damage. To deal with this deficiency, this study formulates an improved curvature mode shape for multiple damage detection in beams based on integrating a wavelet transform (WT) and a Teager energy operator (TEO). The improved curvature mode shape, termed the WT - TEO curvature mode shape, has inherent capabilities of immunity to noise and sensitivity to damage. The proposed method is experimentally validated by identifying multiple cracks in cantilever steel beams with the mode shapes acquired using a scanning laser vibrometer. The results demonstrate that the improved curvature mode shape can identify multiple damage accurately and reliably, and it is fairly robust to measurement noise.

  13. Superior haptic-to-visual shape matching in autism spectrum disorders.

    Science.gov (United States)

    Nakano, Tamami; Kato, Nobumasa; Kitazawa, Shigeru

    2012-04-01

    A weak central coherence theory in autism spectrum disorder (ASD) proposes that a cognitive bias toward local processing in ASD derives from a weakness in integrating local elements into a coherent whole. Using this theory, we hypothesized that shape perception through active touch, which requires sequential integration of sensorimotor traces of exploratory finger movements into a shape representation, would be impaired in ASD. Contrary to our expectation, adults with ASD showed superior performance in a haptic-to-visual delayed shape-matching task compared to adults without ASD. Accuracy in discriminating haptic lengths or haptic orientations, which lies within the somatosensory modality, did not differ between adults with ASD and adults without ASD. Moreover, this superior ability in inter-modal haptic-to-visual shape matching was not explained by the score in a unimodal visuospatial rotation task. These results suggest that individuals with ASD are not impaired in integrating sensorimotor traces into a global visual shape and that their multimodal shape representations and haptic-to-visual information transfer are more accurate than those of individuals without ASD. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. Haptic biofeedback for improving compliance with lower-extremity partial weight bearing.

    Science.gov (United States)

    Fu, Michael C; DeLuke, Levi; Buerba, Rafael A; Fan, Richard E; Zheng, Ying Jean; Leslie, Michael P; Baumgaertner, Michael R; Grauer, Jonathan N

    2014-11-01

    After lower-extremity orthopedic trauma and surgery, patients are often advised to restrict weight bearing on the affected limb. Conventional training methods are not effective at enabling patients to comply with recommendations for partial weight bearing. The current study assessed a novel method of using real-time haptic (vibratory/vibrotactile) biofeedback to improve compliance with instructions for partial weight bearing. Thirty healthy, asymptomatic participants were randomized into 1 of 3 groups: verbal instruction, bathroom scale training, and haptic biofeedback. Participants were instructed to restrict lower-extremity weight bearing in a walking boot with crutches to 25 lb, with an acceptable range of 15 to 35 lb. A custom weight bearing sensor and biofeedback system was attached to all participants, but only those in the haptic biofeedback group were given a vibrotactile signal if they exceeded the acceptable range. Weight bearing in all groups was measured with a separate validated commercial system. The verbal instruction group bore an average of 60.3±30.5 lb (mean±standard deviation). The bathroom scale group averaged 43.8±17.2 lb, whereas the haptic biofeedback group averaged 22.4±9.1 lb (Phaptic biofeedback group averaged 14.5±6.3% (Phaptic biofeedback to improve compliance with lower-extremity partial weight bearing, haptic biofeedback was superior to conventional physical therapy methods. Further studies in patients with clinical orthopedic trauma are warranted. Copyright 2014, SLACK Incorporated.

  15. Vision-Based Haptic Feedback for Remote Micromanipulation in-SEM Environment

    Science.gov (United States)

    Bolopion, Aude; Dahmen, Christian; Stolle, Christian; Haliyo, Sinan; Régnier, Stéphane; Fatikow, Sergej

    2012-07-01

    This article presents an intuitive environment for remote micromanipulation composed of both haptic feedback and virtual reconstruction of the scene. To enable nonexpert users to perform complex teleoperated micromanipulation tasks, it is of utmost importance to provide them with information about the 3-D relative positions of the objects and the tools. Haptic feedback is an intuitive way to transmit such information. Since position sensors are not available at this scale, visual feedback is used to derive information about the scene. In this work, three different techniques are implemented, evaluated, and compared to derive the object positions from scanning electron microscope images. The modified correlation matching with generated template algorithm is accurate and provides reliable detection of objects. To track the tool, a marker-based approach is chosen since fast detection is required for stable haptic feedback. Information derived from these algorithms is used to propose an intuitive remote manipulation system that enables users situated in geographically distant sites to benefit from specific equipments, such as SEMs. Stability of the haptic feedback is ensured by the minimization of the delays, the computational efficiency of vision algorithms, and the proper tuning of the haptic coupling. Virtual guides are proposed to avoid any involuntary collisions between the tool and the objects. This approach is validated by a teleoperation involving melamine microspheres with a diameter of less than 2 μ m between Paris, France and Oldenburg, Germany.

  16. Exploring laterality and memory effects in the haptic discrimination of verbal and non-verbal shapes.

    Science.gov (United States)

    Stoycheva, Polina; Tiippana, Kaisa

    2018-03-14

    The brain's left hemisphere often displays advantages in processing verbal information, while the right hemisphere favours processing non-verbal information. In the haptic domain due to contra-lateral innervations, this functional lateralization is reflected in a hand advantage during certain functions. Findings regarding the hand-hemisphere advantage for haptic information remain contradictory, however. This study addressed these laterality effects and their interaction with memory retention times in the haptic modality. Participants performed haptic discrimination of letters, geometric shapes and nonsense shapes at memory retention times of 5, 15 and 30 s with the left and right hand separately, and we measured the discriminability index d'. The d' values were significantly higher for letters and geometric shapes than for nonsense shapes. This might result from dual coding (naming + spatial) or/and from a low stimulus complexity. There was no stimulus-specific laterality effect. However, we found a time-dependent laterality effect, which revealed that the performance of the left hand-right hemisphere was sustained up to 15 s, while the performance of the right-hand-left hemisphere decreased progressively throughout all retention times. This suggests that haptic memory traces are more robust to decay when they are processed by the left hand-right hemisphere.

  17. Experimental evaluation of magnified haptic feedback for robot-assisted needle insertion and palpation.

    Science.gov (United States)

    Meli, Leonardo; Pacchierotti, Claudio; Prattichizzo, Domenico

    2017-12-01

    Haptic feedback has been proven to play a key role in enhancing the performance of teleoperated medical procedures. However, due to safety issues, commercially-available medical robots do not currently provide the clinician with haptic feedback. This work presents the experimental evaluation of a teleoperation system for robot-assisted medical procedures able to provide magnified haptic feedback to the clinician. Forces registered at the operating table are magnified and provided to the clinician through a 7-DoF haptic interface. The same interface is also used to control the motion of a 6-DoF slave robotic manipulator. The safety of the system is guaranteed by a time-domain passivity-based control algorithm. Two experiments were carried out on stiffness discrimination (during palpation and needle insertion) and one experiment on needle guidance. Our haptic-enabled teleoperation system improved the performance with respect to direct hand interaction of 80%, 306%, and 27% in stiffness discrimination through palpation, stiffness discrimination during needle insertion, and guidance, respectively. Copyright © 2017 John Wiley & Sons, Ltd.

  18. Haptic feedback in OP:Sense - augmented reality in telemanipulated robotic surgery.

    Science.gov (United States)

    Beyl, T; Nicolai, P; Mönnich, H; Raczkowksy, J; Wörn, H

    2012-01-01

    In current research, haptic feedback in robot assisted interventions plays an important role. However most approaches to haptic feedback only regard the mapping of the current forces at the surgical instrument to the haptic input devices, whereas surgeons demand a combination of medical imaging and telemanipulated robotic setups. In this paper we describe how this feature is integrated in our robotic research platform OP:Sense. The proposed method allows the automatic transfer of segmented imaging data to the haptic renderer and therefore allows enriching the haptic feedback with virtual fixtures based on imaging data. Anatomical structures are extracted from pre-operative generated medical images or virtual walls are defined by the surgeon inside the imaging data. Combining real forces with virtual fixtures can guide the surgeon to the regions of interest as well as helps to prevent the risk of damage to critical structures inside the patient. We believe that the combination of medical imaging and telemanipulation is a crucial step for the next generation of MIRS-systems.

  19. Force control tasks with pure haptic feedback promote short-term focused attention.

    Science.gov (United States)

    Wang, Dangxiao; Zhang, Yuru; Yang, Xiaoxiao; Yang, Gaofeng; Yang, Yi

    2014-01-01

    Focused attention has great impact on our quality of life. Our learning, social skills and even happiness are closely intertwined with our capacity for focused attention. Attention promotion is replete with examples of training-induced increases in attention capability, most of which rely on visual and auditory stimulation. Pure haptic stimulation to increase attention capability is rarely found. We show that accurate force control tasks with pure haptic feedback enhance short-term focused attention. Participants were trained by a force control task in which information from visual and auditory channels was blocked, and only haptic feedback was provided. The trainees were asked to exert a target force within a pre-defined force tolerance for a specific duration. The tolerance was adaptively modified to different levels of difficulty to elicit full participant engagement. Three attention tests showed significant changes in different aspects of focused attention in participants who had been trained as compared with those who had not, thereby illustrating the role of haptic-based sensory-motor tasks in the promotion of short-term focused attention. The findings highlight the potential value of haptic stimuli in brain plasticity and serve as a new tool to extend existing computer games for cognitive enhancement.

  20. Design of a New 4-DOF Haptic Master Featuring Magnetorheological Fluid

    Directory of Open Access Journals (Sweden)

    Byung-Keun Song

    2014-08-01

    Full Text Available This work presents a novel 4-degree-of-freedom (4-DOF haptic master using magnetorheological (MR fluid which is applicable to a robot-assisted minimally invasive surgery (RMIS system. By using MR fluid, the proposed haptic device can easily generate bidirectional repulsive torque along the directions of the required motions. The proposed master consists of two actuators: an MR bidirectional clutch associated with a planetary gear system and an MR clutch with a bevel gear system. After demonstrating the configuration, the torque models of MR actuators are mathematically derived based on the field-dependent Bingham model. An optimal design that accounts for spatial-limitation and the desired torque constraint is then undertaken. An optimization procedure based on finite element analysis is proposed to determine optimal geometric dimensions. Based on the design procedure, MR haptic master with the optimal parameters has been manufactured. In order to demonstrate the practical feasibility of the proposed haptic master, the field-dependent generating repulsive force is measured. In addition, a proportional-integral-derivative (PID controller is empirically implemented to accomplish the desired torque trajectories. It has been shown that the proposed haptic master can track the desired torque trajectory without a significant error.

  1. Torque Measurement of 3-DOF Haptic Master Operated by Controllable Electrorheological Fluid

    Directory of Open Access Journals (Sweden)

    Oh Jong-Seok

    2015-02-01

    Full Text Available This work presents a torque measurement method of 3-degree-of-freedom (3-DOF haptic master featuring controllable electrorheological (ER fluid. In order to reflect the sense of an organ for a surgeon, the ER haptic master which can generate the repulsive torque of an organ is utilized as a remote controller for a surgery robot. Since accurate representation of organ feeling is essential for the success of the robot-assisted surgery, it is indispensable to develop a proper torque measurement method of 3-DOF ER haptic master. After describing the structural configuration of the haptic master, the torque models of ER spherical joint are mathematically derived based on the Bingham model of ER fluid. A new type of haptic device which has pitching, rolling, and yawing motions is then designed and manufactured using a spherical joint mechanism. Subsequently, the field-dependent parameters of the Bingham model are identified and generating repulsive torque according to applied electric field is measured. In addition, in order to verify the effectiveness of the proposed torque model, a comparative work between simulated and measured torques is undertaken.

  2. A perspective on the role and utility of haptic feedback in laparoscopic skills training.

    Science.gov (United States)

    Singapogu, Ravikiran; Burg, Timothy; Burg, Karen J L; Smith, Dane E; Eckenrode, Amanda H

    2014-01-01

    Laparoscopic surgery is a minimally invasive surgical technique with significant potential benefits to the patient, including shorter recovery time, less scarring, and decreased costs. There is a growing need to teach surgical trainees this emerging surgical technique. Simulators, ranging from simple "box" trainers to complex virtual reality (VR) trainers, have emerged as the most promising method for teaching basic laparoscopic surgical skills. Current box trainers require oversight from an expert surgeon for both training and assessing skills. VR trainers decrease the dependence on expert teachers during training by providing objective, real-time feedback and automatic skills evaluation. However, current VR trainers generally have limited credibility as a means to prepare new surgeons and have often fallen short of educators' expectations. Several researchers have speculated that the missing component in modern VR trainers is haptic feedback, which refers to the range of touch sensations encountered during surgery. These force types and ranges need to be adequately rendered by simulators for a more complete training experience. This article presents a perspective of the role and utility of haptic feedback during laparoscopic surgery and laparoscopic skills training by detailing the ranges and types of haptic sensations felt by the operating surgeon, along with quantitative studies of how this feedback is used. Further, a number of research studies that have documented human performance effects as a result of the presence of haptic feedback are critically reviewed. Finally, key research directions in using haptic feedback for laparoscopy training simulators are identified.

  3. Design of a 7-DOF haptic master using a magneto-rheological devices for robot surgery

    Science.gov (United States)

    Kang, Seok-Rae; Choi, Seung-Bok; Hwang, Yong-Hoon; Cha, Seung-Woo

    2017-04-01

    This paper presents a 7 degrees-of-freedom (7-DOF) haptic master which is applicable to the robot-assisted minimally invasive surgery (RMIS). By utilizing a controllable magneto-rheological (MR) fluid, the haptic master can provide force information to the surgeon during surgery. The proposed haptic master consists of three degrees motions of X, Y, Z and four degrees motions of the pitch, yaw, roll and grasping. All of them have force feedback capability. The proposed haptic master can generate the repulsive forces or torques by activating MR clutch and MR brake. Both MR clutch and MR brake are designed and manufactured with consideration of the size and output torque which is usable to the robotic surgery. A proportional-integral-derivative (PID) controller is then designed and implemented to achieve torque/force tracking trajectories. It is verified that the proposed haptic master can track well the desired torque and force occurred in the surgical place by controlling the input current applied to MR clutch and brake.

  4. Improving the performance of DTP2 bilateral teleoperation control system with haptic augmentation

    International Nuclear Information System (INIS)

    Viinikainen, Mikko; Tuominen, Janne; Alho, Pekka; Mattila, Jouni

    2014-01-01

    Highlights: •An experimental haptic shared control system, called CAT developed at the DTP2. •We investigate how the system integrates with the ITER compliant DTP2 RHCS. •The effect of CAT experimentally assessed in an ITER relevant maintenance scenario. -- Abstract: The remote maintenance of the ITER divertor is largely dependent on the usage of haptically teleoperated manipulators and man-in-the-loop operations. These maintenance operations are very demanding for the manipulator operators, yet vital for the success of the whole ITER experiment. Haptic shared control of the maintenance manipulators offers a promising solution for assisting the teleoperators in the maintenance tasks. A shared control system assists the operator by generating artificial guiding force effects and overlaying them on top of the haptic feedback from the teleoperation environment. An experimental haptic shared control system, called the Computer Assisted Teleoperation (CAT) has been developed at the Divertor Test Platform 2 (DTP2). In this paper, we investigate the design of the system and how the system integrates with the ITER compliant DTP2 prototype Remote Handling Control System (RHCS). We also experimentally assess the effect of the guidance to the operator performance in an ITER-relevant maintenance scenario using the Water Hydraulic MANipulator (WHMAN), which is specially designed for the divertor maintenance. The result of the experiment gives suggestive indication that the CAT system improves the performance of the operators of the system

  5. Feeling the beat where it counts: fostering multi-limb rhythm skills with the haptic drum kit

    NARCIS (Netherlands)

    Holland, S.; Bouwer, A.J.; Dalgleish, M.; Hurtig, T.M.

    2010-01-01

    This paper introduces a tool known as the Haptic Drum Kit, which employs four computer-controlled vibrotactile devices, one attached to each wrist and ankle. In the applications discussed here, haptic pulses are used to guide the playing, on a drum kit, of rhythmic patterns that require multi-limb

  6. Learning of Temporal and Spatial Movement Aspects: A Comparison of Four Types of Haptic Control and Concurrent Visual Feedback.

    Science.gov (United States)

    Rauter, Georg; Sigrist, Roland; Riener, Robert; Wolf, Peter

    2015-01-01

    In literature, the effectiveness of haptics for motor learning is controversially discussed. Haptics is believed to be effective for motor learning in general; however, different types of haptic control enhance different movement aspects. Thus, in dependence on the movement aspects of interest, one type of haptic control may be effective whereas another one is not. Therefore, in the current work, it was investigated if and how different types of haptic controllers affect learning of spatial and temporal movement aspects. In particular, haptic controllers that enforce active participation of the participants were expected to improve spatial aspects. Only haptic controllers that provide feedback about the task's velocity profile were expected to improve temporal aspects. In a study on learning a complex trunk-arm rowing task, the effect of training with four different types of haptic control was investigated: position control, path control, adaptive path control, and reactive path control. A fifth group (control) trained with visual concurrent augmented feedback. As hypothesized, the position controller was most effective for learning of temporal movement aspects, while the path controller was most effective in teaching spatial movement aspects of the rowing task. Visual feedback was also effective for learning temporal and spatial movement aspects.

  7. Haptic Human-Human Interaction Through a Compliant Connection Does Not Improve Motor Learning in a Force Field

    NARCIS (Netherlands)

    Beckers, Niek; Keemink, Arvid; van Asseldonk, Edwin; van der Kooij, Herman; Prattichizzo, Domenico; Shinoda, Hiroyuki; Tan, Hong Z.; Ruffaldi, Emanuele; Frisoli, Antonio

    2018-01-01

    Humans have a natural ability to haptically interact with other humans, for instance during physically assisting a child to learn how to ride a bicycle. A recent study has shown that haptic human-human interaction can improve individual motor performance and motor learning rate while learning to

  8. Development of visuo-haptic transfer for object recognition in typical preschool and school-aged children.

    Science.gov (United States)

    Purpura, Giulia; Cioni, Giovanni; Tinelli, Francesca

    2018-07-01

    Object recognition is a long and complex adaptive process and its full maturation requires combination of many different sensory experiences as well as cognitive abilities to manipulate previous experiences in order to develop new percepts and subsequently to learn from the environment. It is well recognized that the transfer of visual and haptic information facilitates object recognition in adults, but less is known about development of this ability. In this study, we explored the developmental course of object recognition capacity in children using unimodal visual information, unimodal haptic information, and visuo-haptic information transfer in children from 4 years to 10 years and 11 months of age. Participants were tested through a clinical protocol, involving visual exploration of black-and-white photographs of common objects, haptic exploration of real objects, and visuo-haptic transfer of these two types of information. Results show an age-dependent development of object recognition abilities for visual, haptic, and visuo-haptic modalities. A significant effect of time on development of unimodal and crossmodal recognition skills was found. Moreover, our data suggest that multisensory processes for common object recognition are active at 4 years of age. They facilitate recognition of common objects, and, although not fully mature, are significant in adaptive behavior from the first years of age. The study of typical development of visuo-haptic processes in childhood is a starting point for future studies regarding object recognition in impaired populations.

  9. INVESTIGATION OF CURVES SET BY CUBIC DISTRIBUTION OF CURVATURE

    Directory of Open Access Journals (Sweden)

    S. A. Ustenko

    2014-03-01

    Full Text Available Purpose. Further development of the geometric modeling of curvelinear contours of different objects based on the specified cubic curvature distribution and setpoints of curvature in the boundary points. Methodology. We investigate the flat section of the curvilinear contour generating under condition that cubic curvature distribution is set. Curve begins and ends at the given points, where angles of tangent slope and curvature are also determined. It was obtained the curvature equation of this curve, depending on the section length and coefficient c of cubic curvature distribution. The analysis of obtained equation was carried out. As well as, it was investigated the conditions, in which the inflection points of the curve are appearing. One should find such an interval of parameter change (depending on the input data and the section length, in order to place the inflection point of the curvature graph outside the curve section borders. It was determined the dependence of tangent slope of angle to the curve at its arbitrary point, as well as it was given the recommendations to solve a system of integral equations that allow finding the length of the curve section and the coefficient c of curvature cubic distribution. Findings. As the result of curves research, it is found that the criterion for their selection one can consider the absence of inflection points of the curvature on the observed section. Influence analysis of the parameter c on the graph of tangent slope angle to the curve showed that regardless of its value, it is provided the same rate of angle increase of tangent slope to the curve. Originality. It is improved the approach to geometric modeling of curves based on cubic curvature distribution with its given values at the boundary points by eliminating the inflection points from the observed section of curvilinear contours. Practical value. Curves obtained using the proposed method can be used for geometric modeling of curvilinear

  10. Contrast settling in cerebral aneurysm angiography

    International Nuclear Information System (INIS)

    Wang Zhijie; Hoffmann, Kenneth R; Guterman, Lee R; Wang Zhou; Rudin, Stephen; Meng Hui

    2005-01-01

    During angiography, blood flow is visualized with a radiopaque contrast agent, which is denser than blood. In complex vasculature, such as cerebral saccular aneurysms, the density difference may produce an appreciable gravity effect, where the contrast material separates from blood and settles along the gravity direction. Although contrast settling has been occasionally reported before, the fluid mechanics behind it have not been explored. Furthermore, the severity of contrast settling in cerebral aneurysms varies significantly from case to case. Therefore, a better understanding of the physical principles behind this phenomenon is needed to evaluate contrast settling in clinical angiography. In this study, flow in two identical groups of sidewall aneurysm models with varying parent-vessel curvature was examined by angiography. Intravascular stents were deployed into one group of the models. To detect contrast settling, we used lateral view angiography. Time-intensity curves were analysed from the angiographic data, and a computational fluid dynamic analysis was conducted. Results showed that contrast settling was strongly related to the local flow dynamics. We used the Froude number, a ratio of flow inertia to gravity force, to characterize the significance of gravity force. An aneurysm with a larger vessel curvature experienced higher flow, which resulted in a larger Froude number and, thus, less gravitational settling. Addition of a stent reduced the aneurysmal flow, thereby increasing the contrast settling. We found that contrast settling resulted in an elevated washout tail in the time-intensity curve. However, this signature is not unique to contrast settling. To determine whether contrast settling is present, a lateral view should be obtained in addition to the anteroposterior (AP) view routinely used clinically so as to rule out contrast settling and hence to enable a valid time-intensity curve analysis of blood flow in the aneurysm

  11. The Use of Haptic and Tactile Information in the Car to Improve Driving Safety: A Review of Current Technologies

    Directory of Open Access Journals (Sweden)

    Yoren Gaffary

    2018-03-01

    Full Text Available This paper surveys the haptic technologies deployed in cars and their uses to enhance drivers’ safety during manual driving. These technologies enable to deliver haptic (tactile or kinesthetic feedback at various areas of the car, such as the steering wheel, the seat, or the pedal. The paper explores two main uses of the haptic modality to fulfill the safety objective: to provide driving assistance and warning. Driving assistance concerns the transmission of information usually conveyed with other modalities for controlling the car’s functions, maneuvering support, and guidance. Warning concerns the prevention of accidents using emergency warnings, increasing the awareness of surroundings, and preventing collisions, lane departures, and speeding. This paper discusses how haptic feedback has been introduced so far for these purposes and provides perspectives regarding the present and future of haptic cars meant to increase driver’s safety.

  12. Surface density mapping of natural tissue by a scanning haptic microscope (SHM).

    Science.gov (United States)

    Moriwaki, Takeshi; Oie, Tomonori; Takamizawa, Keiichi; Murayama, Yoshinobu; Fukuda, Toru; Omata, Sadao; Nakayama, Yasuhide

    2013-02-01

    To expand the performance capacity of the scanning haptic microscope (SHM) beyond surface mapping microscopy of elastic modulus or topography, surface density mapping of a natural tissue was performed by applying a measurement theory of SHM, in which a frequency change occurs upon contact of the sample surface with the SHM sensor - a microtactile sensor (MTS) that vibrates at a pre-determined constant oscillation frequency. This change was mainly stiffness-dependent at a low oscillation frequency and density-dependent at a high oscillation frequency. Two paragon examples with extremely different densities but similar macroscopic elastic moduli in the range of natural soft tissues were selected: one was agar hydrogels and the other silicon organogels with extremely low (less than 25 mg/cm(3)) and high densities (ca. 1300 mg/cm(3)), respectively. Measurements were performed in saline solution near the second-order resonance frequency, which led to the elastic modulus, and near the third-order resonance frequency. There was little difference in the frequency changes between the two resonance frequencies in agar gels. In contrast, in silicone gels, a large frequency change by MTS contact was observed near the third-order resonance frequency, indicating that the frequency change near the third-order resonance frequency reflected changes in both density and elastic modulus. Therefore, a density image of the canine aortic wall was subsequently obtained by subtracting the image observed near the second-order resonance frequency from that near the third-order resonance frequency. The elastin-rich region had a higher density than the collagen-rich region.

  13. Vertigo in virtual reality with haptics: case report.

    Science.gov (United States)

    Viirre, Erik; Ellisman, Mark

    2003-08-01

    A researcher was working with a desktop virtual environment system. The system was displaying vector fields of a cyclonic weather system, and the system incorporated a haptic display of the forces in the cyclonic field. As the subject viewed the rotating cyclone field, they would move a handle "through" the representation of the moving winds and "feel" the forces buffeting the handle as it moved. Stopping after using the system for about 10 min, the user experienced an immediate sensation of postural instability for several minutes. Several hours later, there was the onset of vertigo with head turns. This vertigo lasted several hours and was accompanied with nausea and motion illusions that exacerbated by head movements. Symptoms persisted mildly the next day and were still present the third and fourth day, but by then were only provoked by head movements. There were no accompanying symptoms or history to suggest an inner ear disorder. Physical examination of inner ear and associated neurologic function was normal. No other users of this system have reported similar symptoms. This case suggests that some individuals may be susceptible to the interaction of displays with motion and movement forces and as a result experience motion illusions. Operators of such systems should be aware of this potential and minimize exposure if vertigo occurs.

  14. A Haptic Guided Robotic System for Endoscope Positioning and Holding.

    Science.gov (United States)

    Cabuk, Burak; Ceylan, Savas; Anik, Ihsan; Tugasaygi, Mehtap; Kizir, Selcuk

    2015-01-01

    To determine the feasibility, advantages, and disadvantages of using a robot for holding and maneuvering the endoscope in transnasal transsphenoidal surgery. The system used in this study was a Stewart Platform based robotic system that was developed by Kocaeli University Department of Mechatronics Engineering for positioning and holding of endoscope. After the first use on an artificial head model, the system was used on six fresh postmortem bodies that were provided by the Morgue Specialization Department of the Forensic Medicine Institute (Istanbul, Turkey). The setup required for robotic system was easy, the time for registration procedure and setup of the robot takes 15 minutes. The resistance was felt on haptic arm in case of contact or friction with adjacent tissues. The adaptation process was shorter with the mouse to manipulate the endoscope. The endoscopic transsphenoidal approach was achieved with the robotic system. The endoscope was guided to the sphenoid ostium with the help of the robotic arm. This robotic system can be used in endoscopic transsphenoidal surgery as an endoscope positioner and holder. The robot is able to change the position easily with the help of an assistant and prevents tremor, and provides a better field of vision for work.

  15. Magnetic vortices in nanocaps induced by curvature

    Science.gov (United States)

    Abdelgawad, Ahmed M.; Nambiar, Nikhil; Bapna, Mukund; Chen, Hao; Majetich, Sara A.

    2018-05-01

    Magnetic nanoparticles with room temperature remanent magnetic vortices stabilized by their curvature are very intriguing due to their potential use in biomedicine. In the present study, we investigate room temperature magnetic chirality in 100 nm diameter permalloy spherical caps with 10 nm and 30 nm thicknesses. Micromagnetic OOMMF simulations predict the equilibrium spin structure for these caps to form a vortex state. We fabricate the permalloy caps by sputtering permalloy on both close-packed and sparse arrays of polystyrene nanoparticles. Magnetic force microscopy scans show a clear signature of a vortex state in close-packed caps of both 10 nm and 30 nm thicknesses. Alternating gradient magnetometry measurements of the caps are consistent with a remnant vortex state in 30 nm thick caps and a transition to an onion state followed by a vortex state in 10 nm thick caps. Out-of-plane measurements supported by micromagnetic simulations shows that an out-of-plane field can stabilize a vortex state down to a diameter of 15 nm.

  16. Do vision and haptics share common representations? Implicit and explicit memory within and between modalities.

    Science.gov (United States)

    Easton, R D; Srinivas, K; Greene, A J

    1997-01-01

    Previous assessments of verbal cross-modal priming have typically been conducted with the visual and auditory modalities. Within-modal priming is always found to be substantially larger than cross-modal priming, a finding that could reflect modality modularity, or alternatively, differences between the coding of visual and auditory verbal information (i.e., geometric vs. phonological). The present experiments assessed implicit and explicit memory within and between vision and haptics, where verbal information could be coded in geometric terms. Because haptic perception of words is sequential or letter-by-letter, experiments were also conducted to isolate the effects of simultaneous versus sequential processing from the manipulation of modality. Together, the results reveal no effects of modality change on implicit or explicit tests. The authors discuss representational similarities between vision and haptics as well as image mediation as possible explanations for the results.

  17. Selective attention modulates visual and haptic repetition priming: effects in aging and Alzheimer's disease.

    Science.gov (United States)

    Ballesteros, Soledad; Reales, José M; Mayas, Julia; Heller, Morton A

    2008-08-01

    In two experiments, we examined the effect of selective attention at encoding on repetition priming in normal aging and Alzheimer's disease (AD) patients for objects presented visually (experiment 1) or haptically (experiment 2). We used a repetition priming paradigm combined with a selective attention procedure at encoding. Reliable priming was found for both young adults and healthy older participants for visually presented pictures (experiment 1) as well as for haptically presented objects (experiment 2). However, this was only found for attended and not for unattended stimuli. The results suggest that independently of the perceptual modality, repetition priming requires attention at encoding and that perceptual facilitation is maintained in normal aging. However, AD patients did not show priming for attended stimuli, or for unattended visual or haptic objects. These findings suggest an early deficit of selective attention in AD. Results are discussed from a cognitive neuroscience approach.

  18. Haptic-STM: a human-in-the-loop interface to a scanning tunneling microscope.

    Science.gov (United States)

    Perdigão, Luís M A; Saywell, Alex

    2011-07-01

    The operation of a haptic device interfaced with a scanning tunneling microscope (STM) is presented here. The user moves the STM tip in three dimensions by means of a stylus attached to the haptic instrument. The tunneling current measured by the STM is converted to a vertical force, applied to the stylus and felt by the user, with the user being incorporated into the feedback loop that controls the tip-surface distance. A haptic-STM interface of this nature allows the user to feel atomic features on the surface and facilitates the tactile manipulation of the adsorbate/substrate system. The operation of this device is demonstrated via the room temperature STM imaging of C(60) molecules adsorbed on an Au(111) surface in ultra-high vacuum.

  19. A three-axis force sensor for dual finger haptic interfaces.

    Science.gov (United States)

    Fontana, Marco; Marcheschi, Simone; Salsedo, Fabio; Bergamasco, Massimo

    2012-10-10

    In this work we present the design process, the characterization and testing of a novel three-axis mechanical force sensor. This sensor is optimized for use in closed-loop force control of haptic devices with three degrees of freedom. In particular the sensor has been conceived for integration with a dual finger haptic interface that aims at simulating forces that occur during grasping and surface exploration. The sensing spring structure has been purposely designed in order to match force and layout specifications for the application. In this paper the design of the sensor is presented, starting from an analytic model that describes the characteristic matrix of the sensor. A procedure for designing an optimal overload protection mechanism is proposed. In the last part of the paper the authors describe the experimental characterization and the integrated test on a haptic hand exoskeleton showing the improvements in the controller performances provided by the inclusion of the force sensor.

  20. Design of a New MR Compatible Haptic Interface with Six Actuated Degrees of Freedom

    DEFF Research Database (Denmark)

    Ergin, Mehmet Alper; Kühne, Markus; Thielscher, Axel

    2014-01-01

    Functional magnetic resonance imaging is an often adopted tool to study human motor control mechanisms. Highly controlled experiments as required by this form of analysis can be realized with haptic interfaces. Their design is challenging because of strong safety and MR compatibility requirements....... Existing MR-compatible haptic interfaces are restricted to maximum three actuated degrees of freedom. We propose an MR-compatible haptic interface with six actuated degrees of freedom to be able to study human brain mechanisms of natural pick-and-place movements including arm transport. In this work, we...... present its mechanical design, kinematic and dynamic model, as well as report on its model-based characterization. A novel hybrid control scheme for the employed ultrasonic motors is introduced. Preliminary MR compatibility tests based on one complete actuator-sensor module are performed. No measurable...

  1. A Three-Axis Force Sensor for Dual Finger Haptic Interfaces

    Directory of Open Access Journals (Sweden)

    Fabio Salsedo

    2012-10-01

    Full Text Available In this work we present the design process, the characterization and testing of a novel three-axis mechanical force sensor. This sensor is optimized for use in closed-loop force control of haptic devices with three degrees of freedom. In particular the sensor has been conceived for integration with a dual finger haptic interface that aims at simulating forces that occur during grasping and surface exploration. The sensing spring structure has been purposely designed in order to match force and layout specifications for the application. In this paper the design of the sensor is presented, starting from an analytic model that describes the characteristic matrix of the sensor. A procedure for designing an optimal overload protection mechanism is proposed. In the last part of the paper the authors describe the experimental characterization and the integrated test on a haptic hand exoskeleton showing the improvements in the controller performances provided by the inclusion of the force sensor.

  2. IMPROVING MEDICAL EDUCATION: SIMULATING CHANGES IN PATIENT ANATOMY USING DYNAMIC HAPTIC FEEDBACK.

    Science.gov (United States)

    Yovanoff, Mary; Pepley, David; Mirkin, Katelin; Moore, Jason; Han, David; Miller, Scarlett

    2016-09-01

    Virtual simulation is an emerging field in medical education. Research suggests that simulation reduces complication rates and improves learning gains for medical residents. One benefit of simulators is their allowance for more realistic and dynamic patient anatomies. While potentially useful throughout medical education, few studies have explored the impact of dynamic haptic simulators on medical training. In light of this research void, this study was developed to examine how a Dynamic-Haptic Robotic Trainer (DHRT) impacts medical student self-efficacy and skill gains compared to traditional simulators developed to train students in Internal Jugular Central Venous Catheter (IJ CVC) placement. The study was conducted with 18 third year medical students with no prior CVC insertion experience who underwent a pre-test, simulator training (manikin, robotic, or mixed) and post-test. The results revealed the DHRT as a useful method for training CVC skills and supports further research on dynamic haptic trainers in medical education.

  3. A Surgical Robot Teleoperation Framework for Providing Haptic Feedback Incorporating Virtual Envrioment-Based Guidance

    Directory of Open Access Journals (Sweden)

    Adnan Munawar

    2016-08-01

    Full Text Available In robot-assisted tele-operated laparoscopic surgeries, the patient side manipulators are controlled via the master manipulators that are controlled by the surgeon. The current generation of robots approved for laparoscopic surgery lack haptic feedback. In theory, haptic feedback would enhance the surgical procedures by enabling better coordination between the hand movements that are improved by the tactile sense of the operating environment. This research presents an overall control framework for a haptic feedback on existing robot platforms, and demonstrated on the daVinci Research Kit (dVRK system. The paper discusses the implementation of a flexible framework that incorporates a stiffness control with gravity compensation for the surgeons manipulator and a sensing and collision detection algorithm for calculating the interaction between the patients manipulators and the surgical area.

  4. Face recognition based on depth maps and surface curvature

    Science.gov (United States)

    Gordon, Gaile G.

    1991-09-01

    This paper explores the representation of the human face by features based on the curvature of the face surface. Curature captures many features necessary to accurately describe the face, such as the shape of the forehead, jawline, and cheeks, which are not easily detected from standard intensity images. Moreover, the value of curvature at a point on the surface is also viewpoint invariant. Until recently range data of high enough resolution and accuracy to perform useful curvature calculations on the scale of the human face had been unavailable. Although several researchers have worked on the problem of interpreting range data from curved (although usually highly geometrically structured) surfaces, the main approaches have centered on segmentation by signs of mean and Gaussian curvature which have not proved sufficient in themselves for the case of the human face. This paper details the calculation of principal curvature for a particular data set, the calculation of general surface descriptors based on curvature, and the calculation of face specific descriptors based both on curvature features and a priori knowledge about the structure of the face. These face specific descriptors can be incorporated into many different recognition strategies. A system that implements one such strategy, depth template comparison, giving recognition rates between 80% and 90% is described.

  5. Dynamic curvature sensing employing ionic-polymer–metal composite sensors

    International Nuclear Information System (INIS)

    Bahramzadeh, Yousef; Shahinpoor, Mohsen

    2011-01-01

    A dynamic curvature sensor is presented based on ionic-polymer–metal composite (IPMC) for curvature monitoring of deployable/inflatable dynamic space structures. Monitoring the curvature variation is of high importance in various engineering structures including shape monitoring of deployable/inflatable space structures in which the structural boundaries undergo a dynamic deployment process. The high sensitivity of IPMCs to the applied deformations as well as its flexibility make IPMCs a promising candidate for sensing of dynamic curvature changes. Herein, we explore the dynamic response of an IPMC sensor strip with respect to controlled curvature deformations subjected to different forms of input functions. Using a specially designed experimental setup, the voltage recovery effect, phase delay, and rate dependency of the output voltage signal of an IPMC curvature sensor are analyzed. Experimental results show that the IPMC sensor maintains the linearity, sensitivity, and repeatability required for curvature sensing. Besides, in order to describe the dynamic phenomena such as the rate dependency of the IPMC sensor, a chemo-electro-mechanical model based on the Poisson–Nernst–Planck (PNP) equation for the kinetics of ion diffusion is presented. By solving the governing partial differential equations the frequency response of the IPMC sensor is derived. The physical model is able to describe the dynamic properties of the IPMC sensor and the dependency of the signal on rate of excitations

  6. Profile Curvature Derivative Surface used to characterize the complexity of the seafloor around St. John, USVI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Profile curvature was calculated from the bathymetry surface for each raster cell using the ArcGIS 3D Analyst "Curvature" Tool. Profile curvature describes the rate...

  7. Curvature Derivative Surface used to characterize the complexity of the seafloor around St. John, USVI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Curvature was calculated from the bathymetry surface for each raster cell using the ArcGIS 3D Analyst "Curvature" Tool. Curvature describes the rate of change of...

  8. Absence of modulatory action on haptic height perception with musical pitch

    Directory of Open Access Journals (Sweden)

    Michele eGeronazzo

    2015-09-01

    Full Text Available Although acoustic frequency is not a spatial property of physical objects, in common language, pitch, i.e., the psychological correlated of frequency, is often labeled spatially (i.e., high in pitch or low in pitch. Pitch-height is known to modulate (and interact with the response of participants when they are asked to judge spatial properties of non-auditory stimuli (e.g., visual in a variety of behavioral tasks. In the current study we investigated whether the modulatory action of pitch-height extended to the haptic estimation of height of a virtual step.We implemented a HW/SW setup which is able to render virtual 3D objects (stair-steps haptically through a PHANTOM device, and to provide real-time continuous auditory feedback depending on the user interaction with the object. The haptic exploration was associated with a sinusoidal tone whose pitch varied as a function of the interaction point’s height within (i a narrower and (ii a wider pitch range, or (iii a random pitch variation acting as a control audio condition. Explorations were also performed with no sound (haptic only. Participants were instructed to explore the virtual step freely, and to communicate height estimation by opening their thumb and index finger to mimic the step riser height, or verbally by reporting the height in centimeters of the step riser. We analyzed the role of musical expertise by dividing participants into non musicians and musicians. Results showed no effects of musical pitch on high-realistic haptic feedback. Overall there is no difference between the two groups in the proposed multimodal conditions. Additionally, we observed a different haptic response distribution between musicians and non musicians when estimations of the auditory conditions are matched with estimations in the no sound condition.

  9. Influence of Coanda surface curvature on performance of bladeless fan

    Science.gov (United States)

    Li, Guoqi; Hu, Yongjun; Jin, Yingzi; Setoguchi, Toshiaki; Kim, Heuy Dong

    2014-10-01

    The unique Coanda surface has a great influence on the performance of bladeless fan. However, there is few studies to explain the relationship between the performance and Coanda surface curvature at present. In order to gain a qualitative understanding of effect of the curvature on the performance of bladeless fan, numerical studies are performed in this paper. Firstly, three-dimensional numerical simulation is done by Fluent software. For the purpose to obtain detailed information of the flow field around the Coanda surface, two-dimensional numerical simulation is also conducted. Five types of Coanda surfaces with different curvature are designed, and the flow behaviour and the performance of them are analyzed and compared with those of the prototype. The analysis indicates that the curvature of Coanda surface is strongly related to blowing performance, It is found that there is an optimal curvature of Coanda surfaces among the studied models. Simulation result shows that there is a special low pressure region. With increasing curvature in Y direction, several low pressure regions gradually enlarged, then begin to merge slowly, and finally form a large area of low pressure. From the analyses of streamlines and velocity angle, it is found that the magnitude of the curvature affects the flow direction and reasonable curvature can induce fluid flow close to the wall. Thus, it leads to that the curvature of the streamlines is consistent with that of Coanda surface. Meanwhile, it also causes the fluid movement towards the most suitable direction. This study will provide useful information to performance improvements of bladeless fans.

  10. Positive spatial curvature does not falsify the landscape

    Science.gov (United States)

    Horn, B.

    2017-12-01

    We present a simple cosmological model where the quantum tunneling of a scalar field rearranges the energetics of the matter sector, sending a stable static ancestor vacuum with positive spatial curvature into an inating solution with positive curvature. This serves as a proof of principle that an observation of positive spatial curvature does not falsify the hypothesis that our current observer patch originated from false vacuum tunneling in a string or field theoretic landscape. This poster submission is a summary of the work, and was presented at the 3rd annual ICPPA held in Moscow from October 2 to 5, 2017, by Prof. Rostislav Konoplich on behalf of the author.

  11. Curvature perturbation and waterfall dynamics in hybrid inflation

    International Nuclear Information System (INIS)

    Abolhasani, Ali Akbar; Firouzjahi, Hassan; Sasaki, Misao

    2011-01-01

    We investigate the parameter spaces of hybrid inflation model with special attention paid to the dynamics of waterfall field and curvature perturbations induced from its quantum fluctuations. Depending on the inflaton field value at the time of phase transition and the sharpness of the phase transition inflation can have multiple extended stages. We find that for models with mild phase transition the induced curvature perturbation from the waterfall field is too large to satisfy the COBE normalization. We investigate the model parameter space where the curvature perturbations from the waterfall quantum fluctuations vary between the results of standard hybrid inflation and the results obtained here

  12. Curvature perturbation and waterfall dynamics in hybrid inflation

    Energy Technology Data Exchange (ETDEWEB)

    Abolhasani, Ali Akbar [Department of Physics, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Firouzjahi, Hassan [School of Physics, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); Sasaki, Misao, E-mail: abolhasani@mail.ipm.ir, E-mail: firouz@mail.ipm.ir, E-mail: misao@yukawa.kyoto-u.ac.jp [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan)

    2011-10-01

    We investigate the parameter spaces of hybrid inflation model with special attention paid to the dynamics of waterfall field and curvature perturbations induced from its quantum fluctuations. Depending on the inflaton field value at the time of phase transition and the sharpness of the phase transition inflation can have multiple extended stages. We find that for models with mild phase transition the induced curvature perturbation from the waterfall field is too large to satisfy the COBE normalization. We investigate the model parameter space where the curvature perturbations from the waterfall quantum fluctuations vary between the results of standard hybrid inflation and the results obtained here.

  13. Geometry-specific scaling of detonation parameters from front curvature

    International Nuclear Information System (INIS)

    Jackson, Scott I.; Short, Mark

    2011-01-01

    It has previously been asserted that classical detonation curvature theory predicts that the critical diameter and the diameter-effect curve of a cylindrical high-explosive charge should scale with twice the thickness of an analogous two-dimensional explosive slab. The varied agreement of experimental results with this expectation have led some to question the ability of curvature-based concepts to predict detonation propagation in non-ideal explosives. This study addresses such claims by showing that the expected scaling relationship (hereafter referred to d = 2w) is not consistent with curvature-based Detonation Shock Dynamics (DSD) theory.

  14. Numerical studies of transverse curvature effects on transonic flow stability

    Science.gov (United States)

    Macaraeg, M. G.; Daudpota, Q. I.

    1992-01-01

    A numerical study of transverse curvature effects on compressible flow temporal stability for transonic to low supersonic Mach numbers is presented for axisymmetric modes. The mean flows studied include a similar boundary-layer profile and a nonsimilar axisymmetric boundary-layer solution. The effect of neglecting curvature in the mean flow produces only small quantitative changes in the disturbance growth rate. For transonic Mach numbers (1-1.4) and aerodynamically relevant Reynolds numbers (5000-10,000 based on displacement thickness), the maximum growth rate is found to increase with curvature - the maximum occurring at a nondimensional radius (based on displacement thickness) between 30 and 100.

  15. Public and private space curvature in Robertson-Walker universes.

    Science.gov (United States)

    Rindler, W.

    1981-05-01

    The question is asked: what space curvature would a fundamental observer in an ideal Robertson-Walker universe obtain by direct local spatial measurements, i.e., without reference to the motion pattern of the other galaxies? The answer is that he obtains the curvatureK of his “private” space generated by all the geodesics orthogonal to his world line at the moment in question, and that ˜K is related to the usual curvatureK=k/R 2 of the “public” space of galaxies byK=K+H 2/c2, whereH is Hubble's parameter.

  16. Force Sensitive Handles and Capacitive Touch Sensor for Driving a Flexible Haptic-Based Immersive System

    OpenAIRE

    Covarrubias, Mario; Bordegoni, Monica; Cugini, Umberto

    2013-01-01

    In this article, we present an approach that uses both two force sensitive handles (FSH) and a flexible capacitive touch sensor (FCTS) to drive a haptic-based immersive system. The immersive system has been developed as part of a multimodal interface for product design. The haptic interface consists of a strip that can be used by product designers to evaluate the quality of a 3D virtual shape by using touch, vision and hearing and, also, to interactively change the shape of the virtual object...

  17. Ascending and Descending in Virtual Reality: Simple and Safe System Using Passive Haptics.

    Science.gov (United States)

    Nagao, Ryohei; Matsumoto, Keigo; Narumi, Takuji; Tanikawa, Tomohiro; Hirose, Michitaka

    2018-04-01

    This paper presents a novel interactive system that provides users with virtual reality (VR) experiences, wherein users feel as if they are ascending/descending stairs through passive haptic feedback. The passive haptic stimuli are provided by small bumps under the feet of users; these stimuli are provided to represent the edges of the stairs in the virtual environment. The visual stimuli of the stairs and shoes, provided by head-mounted displays, evoke a visuo-haptic interaction that modifies a user's perception of the floor shape. Our system enables users to experience all types of stairs, such as half-turn and spiral stairs, in a VR setting. We conducted a preliminary user study and two experiments to evaluate the proposed technique. The preliminary user study investigated the effectiveness of the basic idea associated with the proposed technique for the case of a user ascending stairs. The results demonstrated that the passive haptic feedback produced by the small bumps enhanced the user's feeling of presence and sense of ascending. We subsequently performed an experiment to investigate an improved viewpoint manipulation method and the interaction of the manipulation and haptics for both the ascending and descending cases. The experimental results demonstrated that the participants had a feeling of presence and felt a steep stair gradient under the condition of haptic feedback and viewpoint manipulation based on the characteristics of actual stair walking data. However, these results also indicated that the proposed system may not be as effective in providing a sense of descending stairs without an optimization of the haptic stimuli. We then redesigned the shape of the small bumps, and evaluated the design in a second experiment. The results indicated that the best shape to present haptic stimuli is a right triangle cross section in both the ascending and descending cases. Although it is necessary to install small protrusions in the determined direction, by

  18. Audio Haptic Videogaming for Developing Wayfinding Skills in Learners Who are Blind.

    Science.gov (United States)

    Sánchez, Jaime; de Borba Campos, Marcia; Espinoza, Matías; Merabet, Lotfi B

    2014-01-01

    Interactive digital technologies are currently being developed as a novel tool for education and skill development. Audiopolis is an audio and haptic based videogame designed for developing orientation and mobility (O&M) skills in people who are blind. We have evaluated the cognitive impact of videogame play on O&M skills by assessing performance on a series of behavioral tasks carried out in both indoor and outdoor virtual spaces. Our results demonstrate that the use of Audiopolis had a positive impact on the development and use of O&M skills in school-aged learners who are blind. The impact of audio and haptic information on learning is also discussed.

  19. The development of a haptic virtual reality environment to study body image and affect.

    Science.gov (United States)

    Tremblay, Line; Bouchard, Stephane; Chebbi, Brahim; Wei, Lai; Monthuy-Blanc, Johana; Boulanger, Dominic

    2013-01-01

    We report the results of a preliminary study testing the effect of participants' mood rating on visual motor performance using a haptic device to manipulate a cartoonish human body. Our results suggest that moods involving high arousal (e.g. happiness) produce larger movements whereas mood involving low arousal (e.g. sadness) produce slower speed of performance. Our results are used for the development of a new haptic virtual reality application that we briefly present here. This application is intended to create a more interactive and motivational environment to treat body image issues and for emotional communication.

  20. Image Structure-Preserving Denoising Based on Difference Curvature Driven Fractional Nonlinear Diffusion

    Directory of Open Access Journals (Sweden)

    Xuehui Yin

    2015-01-01

    Full Text Available The traditional integer-order partial differential equations and gradient regularization based image denoising techniques often suffer from staircase effect, speckle artifacts, and the loss of image contrast and texture details. To address these issues, in this paper, a difference curvature driven fractional anisotropic diffusion for image noise removal is presented, which uses two new techniques, fractional calculus and difference curvature, to describe the intensity variations in images. The fractional-order derivatives information of an image can deal well with the textures of the image and achieve a good tradeoff between eliminating speckle artifacts and restraining staircase effect. The difference curvature constructed by the second order derivatives along the direction of gradient of an image and perpendicular to the gradient can effectively distinguish between ramps and edges. Fourier transform technique is also proposed to compute the fractional-order derivative. Experimental results demonstrate that the proposed denoising model can avoid speckle artifacts and staircase effect and preserve important features such as curvy edges, straight edges, ramps, corners, and textures. They are obviously superior to those of traditional integral based methods. The experimental results also reveal that our proposed model yields a good visual effect and better values of MSSIM and PSNR.

  1. Haptic Cues for Balance: Use of a Cane Provides Immediate Body Stabilization

    Directory of Open Access Journals (Sweden)

    Stefania Sozzi

    2017-12-01

    Full Text Available Haptic cues are important for balance. Knowledge of the temporal features of their effect may be crucial for the design of neural prostheses. Touching a stable surface with a fingertip reduces body sway in standing subjects eyes closed (EC, and removal of haptic cue reinstates a large sway pattern. Changes in sway occur rapidly on changing haptic conditions. Here, we describe the effects and time-course of stabilization produced by a haptic cue derived from a walking cane. We intended to confirm that cane use reduces body sway, to evaluate the effect of vision on stabilization by a cane, and to estimate the delay of the changes in body sway after addition and withdrawal of haptic input. Seventeen healthy young subjects stood in tandem position on a force platform, with eyes closed or open (EO. They gently lowered the cane onto and lifted it from a second force platform. Sixty trials per direction of haptic shift (Touch → NoTouch, T-NT; NoTouch → Touch, NT-T and visual condition (EC-EO were acquired. Traces of Center of foot Pressure (CoP and the force exerted by cane were filtered, rectified, and averaged. The position in space of a reflective marker positioned on the cane tip was also acquired by an optoelectronic device. Cross-correlation (CC analysis was performed between traces of cane tip and CoP displacement. Latencies of changes in CoP oscillation in the frontal plane EC following the T-NT and NT-T haptic shift were statistically estimated. The CoP oscillations were larger in EC than EO under both T and NT (p < 0.001 and larger during NT than T conditions (p < 0.001. Haptic-induced effect under EC (Romberg quotient NT/T ~ 1.2 was less effective than that of vision under NT condition (EC/EO ~ 1.5 (p < 0.001. With EO cane had little effect. Cane displacement lagged CoP displacement under both EC and EO. Latencies to changes in CoP oscillations were longer after addition (NT-T, about 1.6 s than withdrawal (T-NT, about 0.9 s of haptic

  2. Higher Curvature Gravity from Entanglement in Conformal Field Theories

    Science.gov (United States)

    Haehl, Felix M.; Hijano, Eliot; Parrikar, Onkar; Rabideau, Charles

    2018-05-01

    By generalizing different recent works to the context of higher curvature gravity, we provide a unifying framework for three related results: (i) If an asymptotically anti-de Sitter (AdS) spacetime computes the entanglement entropies of ball-shaped regions in a conformal field theory using a generalized Ryu-Takayanagi formula up to second order in state deformations around the vacuum, then the spacetime satisfies the correct gravitational equations of motion up to second order around the AdS background. (ii) The holographic dual of entanglement entropy in higher curvature theories of gravity is given by the Wald entropy plus a particular correction term involving extrinsic curvatures. (iii) Conformal field theory relative entropy is dual to gravitational canonical energy (also in higher curvature theories of gravity). Especially for the second point, our novel derivation of this previously known statement does not involve the Euclidean replica trick.

  3. On the projective curvature tensor of generalized Sasakian-space ...

    African Journals Online (AJOL)

    space-forms under some conditions regarding projective curvature tensor. All the results obtained in this paper are in the form of necessary and sufficient conditions. Keywords: Generalized Sasakian-space-forms; projectively flat; ...

  4. Inverse curvature flows in asymptotically Robertson Walker spaces

    Science.gov (United States)

    Kröner, Heiko

    2018-04-01

    In this paper we consider inverse curvature flows in a Lorentzian manifold N which is the topological product of the real numbers with a closed Riemannian manifold and equipped with a Lorentzian metric having a future singularity so that N is asymptotically Robertson Walker. The flow speeds are future directed and given by 1 / F where F is a homogeneous degree one curvature function of class (K*) of the principal curvatures, i.e. the n-th root of the Gauss curvature. We prove longtime existence of these flows and that the flow hypersurfaces converge to smooth functions when they are rescaled with a proper factor which results from the asymptotics of the metric.

  5. On a class of graphs with prescribed mean curvature

    International Nuclear Information System (INIS)

    Duong Minh Duc; Costa Salavessa, I.M. de

    1989-11-01

    We study a class of quasilinear elliptic equations on the unit ball of R n and apply these results to get the existence of graphs with prescribed mean curvature on n-hyperbolic spaces. (author). 18 refs

  6. Higher-order curvature terms and extended inflation

    International Nuclear Information System (INIS)

    Wang Yun

    1990-01-01

    We consider higher-order curvature terms in context of the Brans-Dicke theory of gravity, and investigate the effects of these terms on extended inflationary theories. We find that the higher-order curvature terms tend to speed up inflation, although the original extended-inflation solutions are stable when these terms are small. Analytical solutions are found for two extreme cases: when the higher-order curvature terms are small, and when they dominate. A conformal transformation is employed in solving the latter case, and some of the subtleties in this technique are discussed. We note that percolation is less likely to occur when the higher-order curvature terms are present. An upper bound on α is expected if we are to avoid excessive and inadequate percolation of true-vacuum bubbles

  7. Gauge and non-gauge curvature tensor copies

    International Nuclear Information System (INIS)

    Srivastava, P.P.

    1982-10-01

    A procedure for constructing curvature tensor copies is discussed using the anholonomic geometrical framework. The corresponding geometries are compared and the notion of gauge copy is elucidated. An explicit calculation is also made. (author)

  8. Bacterial cell curvature through mechanical control of cell growth

    DEFF Research Database (Denmark)

    Cabeen, M.; Charbon, Godefroid; Vollmer, W.

    2009-01-01

    The cytoskeleton is a key regulator of cell morphogenesis. Crescentin, a bacterial intermediate filament-like protein, is required for the curved shape of Caulobacter crescentus and localizes to the inner cell curvature. Here, we show that crescentin forms a single filamentous structure...... that collapses into a helix when detached from the cell membrane, suggesting that it is normally maintained in a stretched configuration. Crescentin causes an elongation rate gradient around the circumference of the sidewall, creating a longitudinal cell length differential and hence curvature. Such curvature...... can be produced by physical force alone when cells are grown in circular microchambers. Production of crescentin in Escherichia coli is sufficient to generate cell curvature. Our data argue for a model in which physical strain borne by the crescentin structure anisotropically alters the kinetics...

  9. Constant scalar curvature hypersurfaces in extended Schwarzschild space-time

    International Nuclear Information System (INIS)

    Pareja, M. J.; Frauendiener, J.

    2006-01-01

    We present a class of spherically symmetric hypersurfaces in the Kruskal extension of the Schwarzschild space-time. The hypersurfaces have constant negative scalar curvature, so they are hyperboloidal in the regions of space-time which are asymptotically flat

  10. Translating Solitons of Mean Curvature Flow of Noncompact Submanifolds

    International Nuclear Information System (INIS)

    Li Guanghan; Tian Daping; Wu Chuanxi

    2011-01-01

    We prove the existence and asymptotic behavior of rotationally symmetric solitons of mean curvature flow for noncompact submanifolds in Euclidean and Minkowski spaces, which generalizes part of the corresponding results for hypersurfaces of Jian.

  11. Curvature and elasticity of substitution: what is the link?

    Czech Academy of Sciences Publication Activity Database

    Matveenko, Andrei; Matveenko, V.

    2014-01-01

    Roč. 10, č. 2 (2014), s. 7-20 ISSN 1800-5845 Grant - others:UK(CZ) GAUK 308214 Institutional support: PRVOUK-P23 Keywords : curvature * elasticity of substitution * production function Subject RIV: AH - Economics

  12. Cosmic censorship, persistent curvature and asymptotic causal pathology

    International Nuclear Information System (INIS)

    Newman, R.P.A.C.

    1984-01-01

    The paper examines cosmic censorship in general relativity theory. Conformally flat space-times; persistent curvature; weakly asymptotically simple and empty asymptotes; censorship conditions; and the censorship theorem; are all discussed. (U.K.)

  13. Displaying Sensed Tactile Cues with a Fingertip Haptic Device.

    Science.gov (United States)

    Pacchierotti, Claudio; Prattichizzo, Domenico; Kuchenbecker, Katherine J

    2015-01-01

    Telerobotic systems enable humans to explore and manipulate remote environments for applications such as surgery and disaster response, but few such systems provide the operator with cutaneous feedback. This article presents a novel approach to remote cutaneous interaction; our method is compatible with any fingertip tactile sensor and any mechanical tactile display device, and it does not require a position/force or skin deformation model. Instead, it directly maps the sensed stimuli to the best possible input commands for the device's motors using a data set recorded with the tactile sensor inside the device. As a proof of concept, we considered a haptic system composed of a BioTac tactile sensor, in charge of measuring contact deformations, and a custom 3-DoF cutaneous device with a flat contact platform, in charge of applying deformations to the user's fingertip. To validate the proposed approach and discover its inherent tradeoffs, we carried out two remote tactile interaction experiments. The first one evaluated the error between the tactile sensations registered by the BioTac in a remote environment and the sensations created by the cutaneous device for six representative tactile interactions and 27 variations of the display algorithm. The normalized average errors in the best condition were 3.0 percent of the BioTac's full 12-bit scale. The second experiment evaluated human subjects' experiences for the same six remote interactions and eight algorithm variations. The average subjective rating for the best algorithm variation was 8.2 out of 10, where 10 is best.

  14. Virtual Reality Robotic Operation Simulations Using MEMICA Haptic System

    Science.gov (United States)

    Bar-Cohen, Y.; Mavroidis, C.; Bouzit, M.; Dolgin, B.; Harm, D. L.; Kopchok, G. E.; White, R.

    2000-01-01

    There is an increasing realization that some tasks can be performed significantly better by humans than robots but, due to associated hazards, distance, etc., only a robot can be employed. Telemedicine is one area where remotely controlled robots can have a major impact by providing urgent care at remote sites. In recent years, remotely controlled robotics has been greatly advanced. The robotic astronaut, "Robonaut," at NASA Johnson Space Center is one such example. Unfortunately, due to the unavailability of force and tactile feedback capability the operator must determine the required action using only visual feedback from the remote site, which limits the tasks that Robonaut can perform. There is a great need for dexterous, fast, accurate teleoperated robots with the operator?s ability to "feel" the environment at the robot's field. Recently, we conceived a haptic mechanism called MEMICA (Remote MEchanical MIrroring using Controlled stiffness and Actuators) that can enable the design of high dexterity, rapid response, and large workspace system. Our team is developing novel MEMICA gloves and virtual reality models to allow the simulation of telesurgery and other applications. The MEMICA gloves are designed to have a high dexterity, rapid response, and large workspace and intuitively mirror the conditions at a virtual site where a robot is simulating the presence of the human operator. The key components of MEMICA are miniature electrically controlled stiffness (ECS) elements and Electrically Controlled Force and Stiffness (ECFS) actuators that are based on the sue of Electro-Rheological Fluids (ERF). In this paper the design of the MEMICA system and initial experimental results are presented.

  15. No Large Scale Curvature Perturbations during Waterfall of Hybrid Inflation

    OpenAIRE

    Abolhasani, Ali Akbar; Firouzjahi, Hassan

    2010-01-01

    In this paper the possibility of generating large scale curvature perturbations induced from the entropic perturbations during the waterfall phase transition of standard hybrid inflation model is studied. We show that whether or not appreciable amounts of large scale curvature perturbations are produced during the waterfall phase transition depend crucially on the competition between the classical and the quantum mechanical back-reactions to terminate inflation. If one considers only the clas...

  16. Existence of conformal metrics on spheres with prescribed Paneitz curvature

    International Nuclear Information System (INIS)

    Ben Ayed, Mohamed; El Mehdi, Khalil

    2003-07-01

    In this paper we study the problem of prescribing a fourth order conformal invariant (the Paneitz curvature) on the n-spheres, with n ≥ 5. Using tools from the theory of critical points at infinity, we provide some topological conditions on the level sets of a given function defined on the sphere, under which we prove the existence of conformal metric with prescribed Paneitz curvature. (author)

  17. Curvature-driven acceleration: a utopia or a reality?

    International Nuclear Information System (INIS)

    Das, Sudipta; Banerjee, Narayan; Dadhich, Naresh

    2006-01-01

    The present work shows that a combination of nonlinear contributions from the Ricci curvature in Einstein field equations can drive a late time acceleration of expansion of the universe. The transit from the decelerated to the accelerated phase of expansion takes place smoothly without having to resort to a study of asymptotic behaviour. This result emphasizes the need for thorough and critical examination of models with nonlinear contribution from the curvature

  18. Curvature-driven acceleration: a utopia or a reality?

    Energy Technology Data Exchange (ETDEWEB)

    Das, Sudipta [Relativity and Cosmology Research Centre, Department of Physics, Jadavpur University, Calcutta-700 032 (India); Banerjee, Narayan [Relativity and Cosmology Research Centre, Department of Physics, Jadavpur University, Calcutta-700 032 (India); Dadhich, Naresh [Inter University Centre for Astronomy and Astrophysics, Post Bag 4, Ganeshkhind, Pune 411 007 (India)

    2006-06-21

    The present work shows that a combination of nonlinear contributions from the Ricci curvature in Einstein field equations can drive a late time acceleration of expansion of the universe. The transit from the decelerated to the accelerated phase of expansion takes place smoothly without having to resort to a study of asymptotic behaviour. This result emphasizes the need for thorough and critical examination of models with nonlinear contribution from the curvature.

  19. Existence of conformal metrics on spheres with prescribed Paneitz curvature

    CERN Document Server

    Ben-Ayed, M

    2003-01-01

    In this paper we study the problem of prescribing a fourth order conformal invariant (the Paneitz curvature) on the n-spheres, with n >= 5. Using tools from the theory of critical points at infinity, we provide some topological conditions on the level sets of a given function defined on the sphere, under which we prove the existence of conformal metric with prescribed Paneitz curvature.

  20. Atomic fine structure in a space of constant curvature

    International Nuclear Information System (INIS)

    Bessis, N.; Bessis, G.; Shamseddine, R.

    1982-01-01

    As a contribution to a tentative formulation of atomic physics in a curved space, the determination of atomic fine structure energies in a space of constant curvature is investigated. Starting from the Dirac equation in a curved space-time, the analogue of the Pauli equation in a general coordinate system is derived. The theoretical curvature induced shifts and splittings of the fine structure energy levels are put in evidence and examined for the particular case of the hydrogenic n=2 levels. (author)

  1. On $L_p$ Affine Surface Area and Curvature Measures

    OpenAIRE

    Zhao, Yiming

    2015-01-01

    The relationship between $L_p$ affine surface area and curvature measures is investigated. As a result, a new representation of the existing notion of $L_p$ affine surface area depending only on curvature measures is derived. Direct proofs of the equivalence between this new representation and those previously known are provided. The proofs show that the new representation is, in a sense, "polar" to that of Lutwak's and "dual" to that of Sch\\"utt & Werner's.

  2. Curvature reduces bending strains in the quokka femur

    Directory of Open Access Journals (Sweden)

    Kyle McCabe

    2017-03-01

    Full Text Available This study explores how curvature in the quokka femur may help to reduce bending strain during locomotion. The quokka is a small wallaby, but the curvature of the femur and the muscles active during stance phase are similar to most quadrupedal mammals. Our hypothesis is that the action of hip extensor and ankle plantarflexor muscles during stance phase place cranial bending strains that act to reduce the caudal curvature of the femur. Knee extensors and biarticular muscles that span the femur longitudinally create caudal bending strains in the caudally curved (concave caudal side bone. These opposing strains can balance each other and result in less strain on the bone. We test this idea by comparing the performance of a normally curved finite element model of the quokka femur to a digitally straightened version of the same bone. The normally curved model is indeed less strained than the straightened version. To further examine the relationship between curvature and the strains in the femoral models, we also tested an extra-curved and a reverse-curved version with the same loads. There appears to be a linear relationship between the curvature and the strains experienced by the models. These results demonstrate that longitudinal curvature in bones may be a manipulable mechanism whereby bone can induce a strain gradient to oppose strains induced by habitual loading.

  3. Curvature recognition and force generation in phagocytosis

    Directory of Open Access Journals (Sweden)

    Prassler Jana

    2010-12-01

    Full Text Available Abstract Background The uptake of particles by actin-powered invagination of the plasma membrane is common to protozoa and to phagocytes involved in the immune response of higher organisms. The question addressed here is how a phagocyte may use geometric cues to optimize force generation for the uptake of a particle. We survey mechanisms that enable a phagocyte to remodel actin organization in response to particles of complex shape. Results Using particles that consist of two lobes separated by a neck, we found that Dictyostelium cells transmit signals concerning the curvature of a surface to the actin system underlying the plasma membrane. Force applied to a concave region can divide a particle in two, allowing engulfment of the portion first encountered. The phagosome membrane that is bent around the concave region is marked by a protein containing an inverse Bin-Amphiphysin-Rvs (I-BAR domain in combination with an Src homology (SH3 domain, similar to mammalian insulin receptor tyrosine kinase substrate p53. Regulatory proteins enable the phagocyte to switch activities within seconds in response to particle shape. Ras, an inducer of actin polymerization, is activated along the cup surface. Coronin, which limits the lifetime of actin structures, is reversibly recruited to the cup, reflecting a program of actin depolymerization. The various forms of myosin-I are candidate motor proteins for force generation in particle uptake, whereas myosin-II is engaged only in retracting a phagocytic cup after a switch to particle release. Thus, the constriction of a phagocytic cup differs from the contraction of a cleavage furrow in mitosis. Conclusions Phagocytes scan a particle surface for convex and concave regions. By modulating the spatiotemporal pattern of actin organization, they are capable of switching between different modes of interaction with a particle, either arresting at a concave region and applying force in an attempt to sever the particle

  4. Neurosurgery simulation using non-linear finite element modeling and haptic interaction

    Science.gov (United States)

    Lee, Huai-Ping; Audette, Michel; Joldes, Grand R.; Enquobahrie, Andinet

    2012-02-01

    Real-time surgical simulation is becoming an important component of surgical training. To meet the realtime requirement, however, the accuracy of the biomechancial modeling of soft tissue is often compromised due to computing resource constraints. Furthermore, haptic integration presents an additional challenge with its requirement for a high update rate. As a result, most real-time surgical simulation systems employ a linear elasticity model, simplified numerical methods such as the boundary element method or spring-particle systems, and coarse volumetric meshes. However, these systems are not clinically realistic. We present here an ongoing work aimed at developing an efficient and physically realistic neurosurgery simulator using a non-linear finite element method (FEM) with haptic interaction. Real-time finite element analysis is achieved by utilizing the total Lagrangian explicit dynamic (TLED) formulation and GPU acceleration of per-node and per-element operations. We employ a virtual coupling method for separating deformable body simulation and collision detection from haptic rendering, which needs to be updated at a much higher rate than the visual simulation. The system provides accurate biomechancial modeling of soft tissue while retaining a real-time performance with haptic interaction. However, our experiments showed that the stability of the simulator depends heavily on the material property of the tissue and the speed of colliding objects. Hence, additional efforts including dynamic relaxation are required to improve the stability of the system.

  5. Effects of a Haptic Augmented Simulation on K-12 Students' Achievement and Their Attitudes Towards Physics

    Science.gov (United States)

    Civelek, Turhan; Ucar, Erdem; Ustunel, Hakan; Aydin, Mehmet Kemal

    2014-01-01

    The current research aims to explore the effects of a haptic augmented simulation on students' achievement and their attitudes towards Physics in an immersive virtual reality environment (VRE). A quasi-experimental post-test design was employed utilizing experiment and control groups. The participants were 215 students from a K-12 school in…

  6. Reducing the motor response in haptic parallel matching eliminates the typically observed gender difference.

    Science.gov (United States)

    van Mier, Hanneke I

    2016-01-01

    When making two bars haptically parallel to each other, large deviations have been observed, most likely caused by the bias of a hand-centered egocentric reference frame. A consistent finding is that women show significantly larger deviations than men when performing this task. It has been suggested that this difference might be due to the fact that women are more egocentrically oriented than men or are less efficient in overcoming the egocentric bias of the hand. If this is indeed the case, reducing the bias of the egocentric reference frame should eliminate the above-mentioned gender difference. This was investigated in the current study. Sixty participants (30 men, 30 women) were instructed to haptically match (task HP) the orientation of a test bar with the dominant hand to the orientation of a reference bar that was perceived with the non-dominant hand. In a haptic visual task (task HV), in which only the reference bar and exploring hand were out of view, no motor response was required, but participants had to "match" the perceived orientation by verbally naming the parallel orientation that was read out on a test protractor. Both females and males performed better in the HV task than in the HP task. Significant gender effects were only found in the haptic parallelity task (HP), corroborating the idea that women perform at the same level as men when the egocentric bias of the hand is reduced.

  7. Social Touch Technology: A Survey of Haptic Technology for Social Touch

    NARCIS (Netherlands)

    Huisman, Gijs

    2017-01-01

    This survey provides an overview of work on haptic technology for social touch. Social touch has been studied extensively in psychology and neuroscience. With the development of new technologies, it is now possible to engage in social touch at a distance or engage in social touch with artificial

  8. Haptic two-dimensional shape identification in children, adolescents, and young adults

    NARCIS (Netherlands)

    Overvliet, Krista E.; Krampe, Ralf Th

    2018-01-01

    We investigated the influence of image mediation (the process that translates tactile information into a visual image) on the development of haptic two-dimensional (2D) shape identification in 78 participants from five different age groups: preschoolers (4–5 years), first graders (6–7 years), fifth

  9. An Investigation on Temporal Aspects in the Audio-Haptic Simulation of Footsteps

    DEFF Research Database (Denmark)

    Turchet, Luca; Serafin, Stefania

    2011-01-01

    In this paper, we present an experiment whose goal is to assess the role of temporal aspects in sonically and haptically simulating the act of walking on a bump or a hole. In particular, we investigated whether the timing between heel and toe and the timing between footsteps affected perception...

  10. 77 FR 20847 - Certain Mobile Electronic Devices Incorporating Haptics; Institution of Investigation Pursuant to...

    Science.gov (United States)

    2012-04-06

    ... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-834] Certain Mobile Electronic Devices Incorporating Haptics; Institution of Investigation Pursuant to 19 U.S.C. 1337 AGENCY: U.S. International Trade.... International Trade Commission on February 7, 2012, and an amended complaint was filed with the U.S...

  11. An MR-Compatible Haptic Interface With Seven Degrees of Freedom

    DEFF Research Database (Denmark)

    Kuhne, Markus; Eschelbach, Martin; Aghaeifar, Ali

    2018-01-01

    Functional magnetic resonance imaging (fMRI) is a powerful tool for neuroscience. It allows the visualization of active areas in the human brain. Combining this method with haptic interfaces allows one to conduct human motor control studies with an opportunity for standardized experimental...

  12. Grounded Learning Experience: Helping Students Learn Physics through Visuo-Haptic Priming and Instruction

    Science.gov (United States)

    Huang, Shih-Chieh Douglas

    2013-01-01

    In this dissertation, I investigate the effects of a grounded learning experience on college students' mental models of physics systems. The grounded learning experience consisted of a priming stage and an instruction stage, and within each stage, one of two different types of visuo-haptic representation was applied: visuo-gestural simulation…

  13. Discriminating Tissue Stiffness with a Haptic Catheter: Feeling the Inside of the Beating Heart.

    Science.gov (United States)

    Kesner, Samuel B; Howe, Robert D

    2011-01-01

    Catheter devices allow physicians to access the inside of the human body easily and painlessly through natural orifices and vessels. Although catheters allow for the delivery of fluids and drugs, the deployment of devices, and the acquisition of the measurements, they do not allow clinicians to assess the physical properties of tissue inside the body due to the tissue motion and transmission limitations of the catheter devices, including compliance, friction, and backlash. The goal of this research is to increase the tactile information available to physicians during catheter procedures by providing haptic feedback during palpation procedures. To accomplish this goal, we have developed the first motion compensated actuated catheter system that enables haptic perception of fast moving tissue structures. The actuated catheter is instrumented with a distal tip force sensor and a force feedback interface that allows users to adjust the position of the catheter while experiencing the forces on the catheter tip. The efficacy of this device and interface is evaluated through a psychophyisical study comparing how accurately users can differentiate various materials attached to a cardiac motion simulator using the haptic device and a conventional manual catheter. The results demonstrate that haptics improves a user's ability to differentiate material properties and decreases the total number of errors by 50% over the manual catheter system.

  14. A novel approach to haptic tele-operation of aerial robot vehicles

    NARCIS (Netherlands)

    Stramigioli, Stefano; Mahony, Robert; Corke, Peter

    2010-01-01

    We present a novel, simple and effective approach for tele-operation of aerial robotic vehicles with haptic feedback. Such feedback provides the remote pilot with an intuitive feel of the robot's state and perceived local environment that will ensure simple and safe operation in cluttered 3D

  15. Haptic shared control improves hot cell remote handling despite controller inaccuracies

    International Nuclear Information System (INIS)

    Oosterhout, J. van; Abbink, D.A.; Koning, J.F.; Boessenkool, H.; Wildenbeest, J.G.W.; Heemskerk, C.J.M.

    2013-01-01

    Highlights: Haptic shared control is generally based upon perfect environment information. A realistic implementation holds model errors with respect to the environment. Operators were aided with inaccurate guiding forces during a peg-in-hole task. The results showed that small guiding inaccuracies still aid the operator. -- Abstract: A promising solution to improve task performance in ITER hot cell remote handling is the use of haptic shared control. Haptic shared control can assist the human operator along a safe and optimal path with continuous guiding forces from an intelligent autonomous controller. Previous research tested such controllers with accurate knowledge of the environment (giving flawless guiding forces), while in a practical implementation guidance forces will sometimes be flawed due to inaccurate models or sensor information. This research investigated the effect of zero and small (7.5 mm) errors on task performance compared to normal (unguided) operation. In a human factors experiment subjects performed a three dimensional virtual reality peg-in-hole type task (30 mm diameter; 0.1 mm clearance), with and without potentially flawed haptic shared control. The results showed that the presence of guiding forces, despite of small guiding errors, still improved task performance with respect to unguided operations

  16. Force Sensitive Handles and Capacitive Touch Sensor for Driving a Flexible Haptic-Based Immersive System

    Directory of Open Access Journals (Sweden)

    Umberto Cugini

    2013-10-01

    Full Text Available In this article, we present an approach that uses both two force sensitive handles (FSH and a flexible capacitive touch sensor (FCTS to drive a haptic-based immersive system. The immersive system has been developed as part of a multimodal interface for product design. The haptic interface consists of a strip that can be used by product designers to evaluate the quality of a 3D virtual shape by using touch, vision and hearing and, also, to interactively change the shape of the virtual object. Specifically, the user interacts with the FSH to move the virtual object and to appropriately position the haptic interface for retrieving the six degrees of freedom required for both manipulation and modification modalities. The FCTS allows the system to track the movement and position of the user’s fingers on the strip, which is used for rendering visual and sound feedback. Two evaluation experiments are described, which involve both the evaluation and the modification of a 3D shape. Results show that the use of the haptic strip for the evaluation of aesthetic shapes is effective and supports product designers in the appreciation of the aesthetic qualities of the shape.

  17. Detection of Membrane Puncture with Haptic Feedback using a Tip-Force Sensing Needle.

    Science.gov (United States)

    Elayaperumal, Santhi; Bae, Jung Hwa; Daniel, Bruce L; Cutkosky, Mark R

    2014-09-01

    This paper presents calibration and user test results of a 3-D tip-force sensing needle with haptic feedback. The needle is a modified MRI-compatible biopsy needle with embedded fiber Bragg grating (FBG) sensors for strain detection. After calibration, the needle is interrogated at 2 kHz, and dynamic forces are displayed remotely with a voice coil actuator. The needle is tested in a single-axis master/slave system, with the voice coil haptic display at the master, and the needle at the slave end. Tissue phantoms with embedded membranes were used to determine the ability of the tip-force sensors to provide real-time haptic feedback as compared to external sensors at the needle base during needle insertion via the master/slave system. Subjects were able to determine the position of the embedded membranes with significantly better accuracy using FBG tip feedback than with base feedback using a commercial force/torque sensor (p = 0.045) or with no added haptic feedback (p = 0.0024).

  18. Slave-side devices for micromanipulation in a haptic teleoperation scenario

    NARCIS (Netherlands)

    Estevez Castillo, P.

    2012-01-01

    Haptic teleoperation is a promising approach for dealing with the manipulation of micro-objects, fabricated in small series or as prototypes, and in processes which are novel or uncertain. Human operators provide their ability to plan, understand and react when faced with unexpected situations

  19. Force sensitive handles and capacitive touch sensor for driving a flexible haptic-based immersive system.

    Science.gov (United States)

    Covarrubias, Mario; Bordegoni, Monica; Cugini, Umberto

    2013-10-09

    In this article, we present an approach that uses both two force sensitive handles (FSH) and a flexible capacitive touch sensor (FCTS) to drive a haptic-based immersive system. The immersive system has been developed as part of a multimodal interface for product design. The haptic interface consists of a strip that can be used by product designers to evaluate the quality of a 3D virtual shape by using touch, vision and hearing and, also, to interactively change the shape of the virtual object. Specifically, the user interacts with the FSH to move the virtual object and to appropriately position the haptic interface for retrieving the six degrees of freedom required for both manipulation and modification modalities. The FCTS allows the system to track the movement and position of the user's fingers on the strip, which is used for rendering visual and sound feedback. Two evaluation experiments are described, which involve both the evaluation and the modification of a 3D shape. Results show that the use of the haptic strip for the evaluation of aesthetic shapes is effective and supports product designers in the appreciation of the aesthetic qualities of the shape.

  20. Palpation imaging using a haptic system for virtual reality applications in medicine.

    Science.gov (United States)

    Khaled, W; Reichling, S; Bruhns, O T; Boese, H; Baumann, M; Monkman, G; Egersdoerfer, S; Klein, D; Tunayar, A; Freimuth, H; Lorenz, A; Pessavento, A; Ermert, H

    2004-01-01

    In the field of medical diagnosis, there is a strong need to determine mechanical properties of biological tissue, which are of histological and pathological relevance. Malignant tumors are significantly stiffer than surrounding healthy tissue. One of the established diagnosis procedures is the palpation of body organs and tissue. Palpation is used to measure swelling, detect bone fracture, find and measure pulse, or to locate changes in the pathological state of tissue and organs. Current medical practice routinely uses sophisticated diagnostic tests through magnetic resonance imaging (MRI), computed tomography (CT) and ultrasound (US) imaging. However, they cannot provide direct measure of tissue elasticity. Last year we presented the concept of the first haptic sensor actuator system to visualize and reconstruct mechanical properties of tissue using ultrasonic elastography and a haptic display with electrorheological fluids. We developed a real time strain imaging system for tumor diagnosis. It allows biopsies simultaneously to conventional ultrasound B-Mode and strain imaging investigations. We deduce the relative mechanical properties by using finite element simulations and numerical solution models solving the inverse problem. Various modifications on the haptic sensor actuator system have been investigated. This haptic system has the potential of inducing real time substantial forces, using a compact lightweight mechanism which can be applied to numerous areas including intraoperative navigation, telemedicine, teaching and telecommunication.

  1. Development of a Robotic Colonoscopic Manipulation System, Using Haptic Feedback Algorithm.

    Science.gov (United States)

    Woo, Jaehong; Choi, Jae Hyuk; Seo, Jong Tae; Kim, Tae Il; Yi, Byung Ju

    2017-01-01

    Colonoscopy is one of the most effective diagnostic and therapeutic tools for colorectal diseases. We aim to propose a master-slave robotic colonoscopy that is controllable in remote site using conventional colonoscopy. The master and slave robot were developed to use conventional flexible colonoscopy. The robotic colonoscopic procedure was performed using a colonoscope training model by one expert endoscopist and two unexperienced engineers. To provide the haptic sensation, the insertion force and the rotating torque were measured and sent to the master robot. A slave robot was developed to hold the colonoscopy and its knob, and perform insertion, rotation, and two tilting motions of colonoscope. A master robot was designed to teach motions of the slave robot. These measured force and torque were scaled down by one tenth to provide the operator with some reflection force and torque at the haptic device. The haptic sensation and feedback system was successful and helpful to feel the constrained force or torque in colon. The insertion time using robotic system decreased with repeated procedures. This work proposed a robotic approach for colonoscopy using haptic feedback algorithm, and this robotic device would effectively perform colonoscopy with reduced burden and comparable safety for patients in remote site.

  2. Design and control of MR haptic master/slave robot system for minimally invasive surgery

    Science.gov (United States)

    Uhm, Chang-Ho; Nguyen, Phoung Bac; Choi, Seung-Bok

    2013-04-01

    In this work, magnetorheological (MR) haptic master and slave robot for minimally invasive surgery (MIS) have been designed and tested. The proposed haptic master consists of four actuators; three MR brakes featuring gimbal structure for 3-DOF rotation motion(X, Y and Z axes) and one MR linear actuator for 1-DOF translational motion. The proposed slave robot which is connected with the haptic master has vertically multi- joints, and it consists of four DC servomotors; three for positioning endoscope and one for spinning motion. We added a fixed bar with a ball joint on the base of the slave for the endoscope position at the patient's abdomen to maintain safety. A gimbal structure at the end of the slave robotic arm for the last joint rotates freely with respect to the pivot point of the fixed bar. This master-slave system runs as if a teleoperation system through TCP/IP connection, programmed by LabVIEW. In order to achieve the desired position trajectory, a proportional-integral-derivative (PID) controller is designed and implemented. It has been demonstrated that the effective tracking control performances for the desired motion are well achieved and presented in time domain. At last, an experiment in virtual environments is undertaken to investigate the effectiveness of the MR haptic master device for MIS system.

  3. Sound Descriptions of Haptic Experiences of Art Work by Deafblind Cochlear Implant Users

    Directory of Open Access Journals (Sweden)

    Riitta Lahtinen

    2018-05-01

    Full Text Available Deafblind persons’ perception and experiences are based on their residual auditive and visual senses, and touch. Their haptic exploration, through movements and orientation towards objects give blind persons direct, independent experience. Few studies explore the aesthetic experiences and appreciation of artefacts of deafblind people using cochlear implant (CI technology, and how they interpret and express their perceived aesthetic experience through another sensory modality. While speech recognition is studied extensively in this area, the aspect of auditive descriptions made by CI users are a less-studied domain. This present research intervention describes and analyses five different deafblind people sharing their interpretation of five statues vocally, using sounds and written descriptions based on their haptic explorations. The participants found new and multimodal ways of expressing their experiences, as well as re-experiencing them through technological aids. We also found that the CI users modify technology to better suit their personal needs. We conclude that CI technology in combination with self-made sound descriptions enhance memorization of haptic art experiences that can be re-called by the recording of the sound descriptions. This research expands the idea of auditive descriptions, and encourages user-produced descriptions as artistic supports to traditional linguistic, audio descriptions. These can be used to create personal auditive–haptic memory collections similar to how sighted create photo albums.

  4. Design of a smart haptic system for repulsive force control under irregular manipulation environment

    International Nuclear Information System (INIS)

    Lee, Sang-Rock; Choi, Seung-Hyun; Choi, Seung-Bok; Cho, Myeong-Woo

    2014-01-01

    This paper describes how to make an operator feel the desired repulsive force in a haptic system. When an operator manipulates a haptic system, the repulsive force of the operator varies significantly, depending on many factors such as position, velocity and force. In order to reflect the desired repulsive force to the operator, it is commonly known that a haptic system must compensate for irregularly changing forces. The irregularity of the forces, however, has discouraged many researchers from establishing a clear principle on how to make the operator feel the desired repulsive force. To resolve this problem, we introduce a smart haptic framework that can reflect the desired repulsive force to the operator, regardless of the operator’s movement. A dummy governing equation technique is introduced and used to calculate the proper actuating force in real time. The actuating force is generated by a PID controller. To verify the proposed method, a mathematical proof is offered to show that the repulsive force converges to the desired repulsive force. Additionally, to demonstrate the performance of the proposed method, simulational and experimental tests are implemented. (paper)

  5. Human-Multi-Robot Teleoperation for Cooperative Manipulation Tasks using Wearable Haptic Devices

    DEFF Research Database (Denmark)

    Chinello, Francesco

    2017-01-01

    . Control inputs for both subtasks are provided by the human. The inputs are projected onto the space of subtasks using a forward mapping strategy. Measured wrenches are projected onto the feedback signals provided to the human via wearable fingertip haptic devices through a feedback mapping strategy...

  6. Guidelines for haptic interpersonal communication applications : an exploration of foot interaction styles

    NARCIS (Netherlands)

    Rovers, A.F.; Essen, van H.A.

    2006-01-01

    A new method for researching haptic interaction styles is presented, based on a layered interaction model and a classification of existing devices. The method is illustrated by designing a new foot interaction device. The aim of which is to enhance non-verbal communication over a computer network. A

  7. Vibrotactile perception assessment for a haptic interface on an antigravity suit.

    Science.gov (United States)

    Ko, Sang Min; Lee, Kwangil; Kim, Daeho; Ji, Yong Gu

    2017-01-01

    Haptic technology is used in various fields to transmit information to the user with or without visual and auditory cues. This study aimed to provide preliminary data for use in developing a haptic interface for an antigravity (anti-G) suit. With the structural characteristics of the anti-G suit in mind, we determined five areas on the body (lower back, outer thighs, inner thighs, outer calves, and inner calves) on which to install ten bar-type eccentric rotating mass (ERM) motors as vibration actuators. To determine the design factors of the haptic anti-G suit, we conducted three experiments to find the absolute threshold, moderate intensity, and subjective assessments of vibrotactile stimuli. Twenty-six fighter pilots participated in the experiments, which were conducted in a fixed-based flight simulator. From the results of our study, we recommend 1) absolute thresholds of ∼11.98-15.84 Hz and 102.01-104.06 dB, 2) moderate intensities of 74.36 Hz and 126.98 dB for the lower back and 58.65 Hz and 122.37 dB for either side of the thighs and calves, and 3) subjective assessments of vibrotactile stimuli (displeasure, easy to perceive, and level of comfort). The results of this study will be useful for the design of a haptic anti-G suit. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Design and evaluation of a Flight Envelope Protection haptic feedback system

    NARCIS (Netherlands)

    Ellerbroek, J.; Rodriguez Martin, M.J.M.; Lombaerts, T; van Paassen, M.M.; Mulder, M.

    2016-01-01

    This paper describes the design and evaluation of a shared control, haptic feedback system to communicate Flight Envelope Protection System intent. The concept uses a combination of stiffness feedback and vibration to communicate proximity of the aircraft state to flight envelope boundaries. In

  9. Optimal design of a new 3D haptic gripper for telemanipulation, featuring magnetorheological fluid brakes

    International Nuclear Information System (INIS)

    Nguyen, Q H; Choi, S B; Lee, Y S; Han, M S

    2013-01-01

    In this research work, a new configuration of a 3D haptic gripper for telemanipulation is proposed and optimally designed. The proposed haptic gripper, featuring three magnetorheological fluid brakes (MRBs), reflects the rolling torque, the grasping force and the approach force from the slave manipulator to the master operator. After describing the operational principle of the haptic gripper, an optimal design of the MRBs for the gripper is performed. The purpose of the optimization problem is to find the most compact MRB that can provide a required braking torque/force to the master operator while the off-state torque/force is kept as small as possible. In the optimal design, different types of MRBs and different MR fluids (MRFs) are considered. In order to obtain the optimal solution of the MRBs, an optimization approach based on finite element analysis (FEA) integrated with an optimization tool is used. The optimal solutions of the MRBs are then obtained and the optimized MRBs for the haptic gripper are identified. In addition, discussions on the optimal solutions and performance of the optimized MRBs are given. (paper)

  10. Virtual reality cerebral aneurysm clipping simulation with real-time haptic feedback.

    Science.gov (United States)

    Alaraj, Ali; Luciano, Cristian J; Bailey, Daniel P; Elsenousi, Abdussalam; Roitberg, Ben Z; Bernardo, Antonio; Banerjee, P Pat; Charbel, Fady T

    2015-03-01

    With the decrease in the number of cerebral aneurysms treated surgically and the increase of complexity of those treated surgically, there is a need for simulation-based tools to teach future neurosurgeons the operative techniques of aneurysm clipping. To develop and evaluate the usefulness of a new haptic-based virtual reality simulator in the training of neurosurgical residents. A real-time sensory haptic feedback virtual reality aneurysm clipping simulator was developed using the ImmersiveTouch platform. A prototype middle cerebral artery aneurysm simulation was created from a computed tomographic angiogram. Aneurysm and vessel volume deformation and haptic feedback are provided in a 3-dimensional immersive virtual reality environment. Intraoperative aneurysm rupture was also simulated. Seventeen neurosurgery residents from 3 residency programs tested the simulator and provided feedback on its usefulness and resemblance to real aneurysm clipping surgery. Residents thought that the simulation would be useful in preparing for real-life surgery. About two-thirds of the residents thought that the 3-dimensional immersive anatomic details provided a close resemblance to real operative anatomy and accurate guidance for deciding surgical approaches. They thought the simulation was useful for preoperative surgical rehearsal and neurosurgical training. A third of the residents thought that the technology in its current form provided realistic haptic feedback for aneurysm surgery. Neurosurgical residents thought that the novel immersive VR simulator is helpful in their training, especially because they do not get a chance to perform aneurysm clippings until late in their residency programs.

  11. Haptic shared control improves hot cell remote handling despite controller inaccuracies

    Energy Technology Data Exchange (ETDEWEB)

    Oosterhout, J. van, E-mail: J.vanOosterhout@differ.nl [Delft University of Technology, Faculty of 3mE, BioMechanical Engineering Department, Mekelweg 2, 2628 CD Delft (Netherlands); Abbink, D.A. [Delft University of Technology, Faculty of 3mE, BioMechanical Engineering Department, Mekelweg 2, 2628 CD Delft (Netherlands); Koning, J.F. [Heemskerk Innovative Technology B.V., Jonckerweg 12, 2201 DZ Noordwijk (Netherlands); Boessenkool, H. [FOM Institute DIFFER (Dutch Institute for Fundamental Energy Research), Association EURATOM-FOM, Partner in the Trilateral Euregio Cluster, PO Box 1207, 3430 BE Nieuwegein (Netherlands); Wildenbeest, J.G.W. [Delft University of Technology, Faculty of 3mE, BioMechanical Engineering Department, Mekelweg 2, 2628 CD Delft (Netherlands); Heemskerk Innovative Technology B.V., Jonckerweg 12, 2201 DZ Noordwijk (Netherlands); Heemskerk, C.J.M. [Heemskerk Innovative Technology B.V., Jonckerweg 12, 2201 DZ Noordwijk (Netherlands)

    2013-10-15

    Highlights: Haptic shared control is generally based upon perfect environment information. A realistic implementation holds model errors with respect to the environment. Operators were aided with inaccurate guiding forces during a peg-in-hole task. The results showed that small guiding inaccuracies still aid the operator. -- Abstract: A promising solution to improve task performance in ITER hot cell remote handling is the use of haptic shared control. Haptic shared control can assist the human operator along a safe and optimal path with continuous guiding forces from an intelligent autonomous controller. Previous research tested such controllers with accurate knowledge of the environment (giving flawless guiding forces), while in a practical implementation guidance forces will sometimes be flawed due to inaccurate models or sensor information. This research investigated the effect of zero and small (7.5 mm) errors on task performance compared to normal (unguided) operation. In a human factors experiment subjects performed a three dimensional virtual reality peg-in-hole type task (30 mm diameter; 0.1 mm clearance), with and without potentially flawed haptic shared control. The results showed that the presence of guiding forces, despite of small guiding errors, still improved task performance with respect to unguided operations.

  12. Real-time dual-band haptic music player for mobile devices.

    Science.gov (United States)

    Hwang, Inwook; Lee, Hyeseon; Choi, Seungmoon

    2013-01-01

    We introduce a novel dual-band haptic music player for real-time simultaneous vibrotactile playback with music in mobile devices. Our haptic music player features a new miniature dual-mode actuator that can produce vibrations consisting of two principal frequencies and a real-time vibration generation algorithm that can extract vibration commands from a music file for dual-band playback (bass and treble). The algorithm uses a "haptic equalizer" and provides plausible sound-to-touch modality conversion based on human perceptual data. In addition, we present a user study carried out to evaluate the subjective performance (precision, harmony, fun, and preference) of the haptic music player, in comparison with the current practice of bass-band-only vibrotactile playback via a single-frequency voice-coil actuator. The evaluation results indicated that the new dual-band playback outperforms the bass-only rendering, also providing several insights for further improvements. The developed system and experimental findings have implications for improving the multimedia experience with mobile devices.

  13. Switching-based Mapping and Control for Haptic Teleoperation of Aerial Robots

    NARCIS (Netherlands)

    Mersha, A.Y.; Stramigioli, Stefano; Carloni, Raffaella

    2012-01-01

    This paper deals with the bilateral teleoperation of underactuated aerial robots by means of a haptic interface. In particular, we propose a switching-based state mapping and control algorithm between a rate-based passive controller, which addresses the workspace incompatibility between the master

  14. The Hedonic Haptics Player: A Wearable Device to Experience Vibrotactile Compositions

    DEFF Research Database (Denmark)

    Boer, Laurens; Vallgårda, Anna; Cahill, Ben

    2017-01-01

    The Hedonic Haptics player is a portable wearable device that plays back vibrotactile compositions. It consists of three domes each of which houses a vibration motor providing vibrotactile sensations to the wearer. The domes are connected to a control unit the size of a small Walkman. The Hedonic...

  15. Kinetic scrolling-based position mapping for haptic teleoperation of unmanned aerial vehicles

    NARCIS (Netherlands)

    Ruesch, A.; Mersha, A.Y.; Stramigioli, Stefano; Carloni, Raffaella

    In this paper, we present a haptic teleoperation control algorithm for unmanned aerial vehicles, applying a kinetic scrolling-based position mapping. The proposed algorithm overcomes the master workspace limitations and enables to teleoperate the aerial vehicle in unbounded workspace in a fast and

  16. Massage Therapy of the Back Using a Real-Time Haptic-Enhanced Telerehabilitation System

    Directory of Open Access Journals (Sweden)

    Cristina Ramírez-Fernández

    2017-01-01

    Full Text Available We present the usability evaluation of a haptic-enhanced telerehabilitation system for massage therapy of the back using the Vybe haptic gaming pad and the gesture sensor LEAP motion controller. The evaluated system includes features that allow for (i administering online therapy programs, (ii providing self-adjustable and safety treatment of back massages using a virtual environment, and (iii saving and replaying massage sessions according to a patient’s therapy program. The usability evaluation with 25 older adults and 10 specialists suggests that the haptic telerehabilitation system is perceived with high usability and pleasurable user experience, while providing personalized intensity of haptic therapy in a supervised, real-time, and secure way to treat the patient. Moreover, the specialists totally agree that the system design features, such as save and play, and delimiting therapy zones are the most important for back massage therapy, while the features of regulating feedback intensity and providing/receiving a massage remotely are also important. Finally, based on their comments, five design insights aiming at improving the current version of the system were generated.

  17. Development of a Robotic Colonoscopic Manipulation System, Using Haptic Feedback Algorithm

    Science.gov (United States)

    Woo, Jaehong; Choi, Jae Hyuk; Seo, Jong Tae

    2017-01-01

    Purpose Colonoscopy is one of the most effective diagnostic and therapeutic tools for colorectal diseases. We aim to propose a master-slave robotic colonoscopy that is controllable in remote site using conventional colonoscopy. Materials and Methods The master and slave robot were developed to use conventional flexible colonoscopy. The robotic colonoscopic procedure was performed using a colonoscope training model by one expert endoscopist and two unexperienced engineers. To provide the haptic sensation, the insertion force and the rotating torque were measured and sent to the master robot. Results A slave robot was developed to hold the colonoscopy and its knob, and perform insertion, rotation, and two tilting motions of colonoscope. A master robot was designed to teach motions of the slave robot. These measured force and torque were scaled down by one tenth to provide the operator with some reflection force and torque at the haptic device. The haptic sensation and feedback system was successful and helpful to feel the constrained force or torque in colon. The insertion time using robotic system decreased with repeated procedures. Conclusion This work proposed a robotic approach for colonoscopy using haptic feedback algorithm, and this robotic device would effectively perform colonoscopy with reduced burden and comparable safety for patients in remote site. PMID:27873506

  18. 77 FR 49458 - Certain Mobile Electronic Devices Incorporating Haptics; Amendment of the Complaint and Notice of...

    Science.gov (United States)

    2012-08-16

    ... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-834] Certain Mobile Electronic Devices.... 1337 in the importation, sale for importation, and sale within the United States after importation of certain mobile electronic devices incorporating haptics, by reason of the infringement of claims of six...

  19. 78 FR 23593 - Certain Mobile Electronic Devices Incorporating Haptics; Termination of Investigation

    Science.gov (United States)

    2013-04-19

    ... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-834] Certain Mobile Electronic Devices... the importation, sale for importation, and sale within the United States after importation of certain mobile electronic devices incorporating haptics that infringe certain claims of six Immersion patents. 77...

  20. Using haptic feedback to increase seat belt use of service vehicle drivers.

    Science.gov (United States)

    2011-01-01

    This study pilot-tested a new application of a technology-based intervention to increase seat belt use. The technology was based on a : contingency in which unbelted drivers experienced sustained haptic feedback to the gas pedal when they exceeded 25...

  1. Audio-haptic physically-based simulation of walking on different grounds

    DEFF Research Database (Denmark)

    Turchet, Luca; Nordahl, Rolf; Serafin, Stefania

    2010-01-01

    We describe a system which simulates in realtime the auditory and haptic sensations of walking on different surfaces. The system is based on a pair of sandals enhanced with pressure sensors and actuators. The pressure sensors detect the interaction force during walking, and control several...

  2. Mediating Haptic Exploratory Strategies in Children Who Have Visual Impairment and Intellectual Disabilities

    Science.gov (United States)

    McLinden, M.

    2012-01-01

    This article provides a synthesis of literature pertaining to the development of haptic exploratory strategies in children who have visual impairment and intellectual disabilities. The information received through such strategies assumes particular significance for these children, given the restricted information available through their visual…

  3. Improved Haptic Linear Lines for Better Movement Accuracy in Upper Limb Rehabilitation

    Directory of Open Access Journals (Sweden)

    Joan De Boeck

    2012-01-01

    Full Text Available Force feedback has proven to be beneficial in the domain of robot-assisted rehabilitation. According to the patients' personal needs, the generated forces may either be used to assist, support, or oppose their movements. In our current research project, we focus onto the upper limb training for MS (multiple sclerosis and CVA (cerebrovascular accident patients, in which a basic building block to implement many rehabilitation exercises was found. This building block is a haptic linear path: a second-order continuous path, defined by a list of points in space. Earlier, different attempts have been investigated to realize haptic linear paths. In order to have a good training quality, it is important that the haptic simulation is continuous up to the second derivative while the patient is enforced to follow the path tightly, even when low or no guiding forces are provided. In this paper, we describe our best solution to these haptic linear paths, discuss the weaknesses found in practice, and propose and validate an improvement.

  4. Effects of visual information regarding allocentric processing in haptic parallelity matching.

    Science.gov (United States)

    Van Mier, Hanneke I

    2013-10-01

    Research has revealed that haptic perception of parallelity deviates from physical reality. Large and systematic deviations have been found in haptic parallelity matching most likely due to the influence of the hand-centered egocentric reference frame. Providing information that increases the influence of allocentric processing has been shown to improve performance on haptic matching. In this study allocentric processing was stimulated by providing informative vision in haptic matching tasks that were performed using hand- and arm-centered reference frames. Twenty blindfolded participants (ten men, ten women) explored the orientation of a reference bar with the non-dominant hand and subsequently matched (task HP) or mirrored (task HM) its orientation on a test bar with the dominant hand. Visual information was provided by means of informative vision with participants having full view of the test bar, while the reference bar was blocked from their view (task VHP). To decrease the egocentric bias of the hands, participants also performed a visual haptic parallelity drawing task (task VHPD) using an arm-centered reference frame, by drawing the orientation of the reference bar. In all tasks, the distance between and orientation of the bars were manipulated. A significant effect of task was found; performance improved from task HP, to VHP to VHPD, and HM. Significant effects of distance were found in the first three tasks, whereas orientation and gender effects were only significant in tasks HP and VHP. The results showed that stimulating allocentric processing by means of informative vision and reducing the egocentric bias by using an arm-centered reference frame led to most accurate performance on parallelity matching. © 2013 Elsevier B.V. All rights reserved.

  5. Advanced Maintenance Simulation by Means of Hand-Based Haptic Interfaces

    Science.gov (United States)

    Nappi, Michele; Paolino, Luca; Ricciardi, Stefano; Sebillo, Monica; Vitiello, Giuliana

    Aerospace industry has been involved in virtual simulation for design and testing since the birth of virtual reality. Today this industry is showing a growing interest in the development of haptic-based maintenance training applications, which represent the most advanced way to simulate maintenance and repair tasks within a virtual environment by means of a visual-haptic approach. The goal is to allow the trainee to experiment the service procedures not only as a workflow reproduced at a visual level but also in terms of the kinaesthetic feedback involved with the manipulation of tools and components. This study, conducted in collaboration with aerospace industry specialists, is aimed to the development of an immersive virtual capable of immerging the trainees into a virtual environment where mechanics and technicians can perform maintenance simulation or training tasks by directly manipulating 3D virtual models of aircraft parts while perceiving force feedback through the haptic interface. The proposed system is based on ViRstperson, a virtual reality engine under development at the Italian Center for Aerospace Research (CIRA) to support engineering and technical activities such as design-time maintenance procedure validation, and maintenance training. This engine has been extended to support haptic-based interaction, enabling a more complete level of interaction, also in terms of impedance control, and thus fostering the development of haptic knowledge in the user. The user’s “sense of touch” within the immersive virtual environment is simulated through an Immersion CyberForce® hand-based force-feedback device. Preliminary testing of the proposed system seems encouraging.

  6. Modeling and test of a kinaesthetic actuator based on MR fluid for haptic applications.

    Science.gov (United States)

    Yang, Tae-Heon; Koo, Jeong-Hoi; Kim, Sang-Youn; Kwon, Dong-Soo

    2017-03-01

    Haptic display units have been widely used for conveying button sensations to users, primarily employing vibrotactile actuators. However, the human feeling for pressing buttons mainly relies on kinaesthetic sensations (rather than vibrotactile sensations), and little studies exist on small-scale kinaesthetic haptic units. Thus, the primary goals of this paper are to design a miniature kinaesthetic actuator based on Magneto-Rheological (MR) fluid that can convey various button-clicking sensations and to experimentally evaluate its haptic performance. The design focuses of the proposed actuator were to produce sufficiently large actuation forces (resistive forces) for human users in a given size constraint and to offer a wide range of actuation forces for conveying vivid haptic sensations to users. To this end, this study first performed a series of parametric studies using mathematical force models for multiple operating modes of MR fluid in conjunction with finite element electromagnetism analysis. After selecting design parameters based on parametric studies, a prototype actuator was constructed, and its performance was evaluated using a dynamic mechanical analyzer. It measured the actuator's resistive force with a varying stroke (pressed depth) up to 1 mm and a varying input current from 0 A to 200 mA. The results show that the proposed actuator creates a wide range of resistive forces from around 2 N (off-state) to over 9.5 N at 200 mA. In order to assess the prototype's performance in the terms of the haptic application prospective, a maximum force rate was calculated to determine just noticeable difference in force changes for the 1 mm stoke of the actuator. The results show that the force rate is sufficient to mimic various levels of button sensations, indicating that the proposed kinaesthetic actuator can offer a wide range of resistive force changes that can be conveyed to human operators.

  7. Novel tilt-curvature coupling in lipid membranes

    Science.gov (United States)

    Terzi, M. Mert; Deserno, Markus

    2017-08-01

    On mesoscopic scales, lipid membranes are well described by continuum theories whose main ingredients are the curvature of a membrane's reference surface and the tilt of its lipid constituents. In particular, Hamm and Kozlov [Eur. Phys. J. E 3, 323 (2000)] have shown how to systematically derive such a tilt-curvature Hamiltonian based on the elementary assumption of a thin fluid elastic sheet experiencing internal lateral pre-stress. Performing a dimensional reduction, they not only derive the basic form of the effective surface Hamiltonian but also express its emergent elastic couplings as trans-membrane moments of lower-level material parameters. In the present paper, we argue, though, that their derivation unfortunately missed a coupling term between curvature and tilt. This term arises because, as one moves along the membrane, the curvature-induced change of transverse distances contributes to the area strain—an effect that was believed to be small but nevertheless ends up contributing at the same (quadratic) order as all other terms in their Hamiltonian. We illustrate the consequences of this amendment by deriving the monolayer and bilayer Euler-Lagrange equations for the tilt, as well as the power spectra of shape, tilt, and director fluctuations. A particularly curious aspect of our new term is that its associated coupling constant is the second moment of the lipid monolayer's lateral stress profile—which within this framework is equal to the monolayer Gaussian curvature modulus, κ¯ m. On the one hand, this implies that many theoretical predictions now contain a parameter that is poorly known (because the Gauss-Bonnet theorem limits access to the integrated Gaussian curvature); on the other hand, the appearance of κ¯ m outside of its Gaussian curvature provenance opens opportunities for measuring it by more conventional means, for instance by monitoring a membrane's undulation spectrum at short scales.

  8. Spinal curvature and characteristics of postural change in pregnant women.

    Science.gov (United States)

    Okanishi, Natsuko; Kito, Nobuhiro; Akiyama, Mitoshi; Yamamoto, Masako

    2012-07-01

    Pregnant women often report complaints due to physiological and postural changes. Postural changes during pregnancy may cause low back pain and pelvic girdle pain. This study aimed to compare the characteristics of postural changes in pregnant compared with non-pregnant women. Prospective case-control study. Pregnancy care center. Fifteen women at 17-34 weeks pregnancy comprised the study group, while 10 non-pregnant female volunteers comprised the control group. Standing posture was evaluated in the sagittal plane with static digital pictures. Two angles were measured by image analysis software: (1) between the trunk and pelvis; and (2) between the trunk and lower extremity. Spinal curvature was measured with Spinal Mouse® to calculate the means of sacral inclination, thoracic and lumbar curvature and inclination. The principal components were calculated until eigenvalues surpassed 1. Three distinct factors with eigenvalues of 1.00-2.49 were identified, consistent with lumbosacral spinal curvature and inclination, thoracic spine curvature, and inclination of the body. These factors accounted for 77.2% of the total variance in posture variables. Eleven pregnant women showed postural characteristics of lumbar kyphosis and sacral posterior inclination. Body inclination showed a variety of patterns compared with those in healthy women. Spinal curvature demonstrated a tendency for lumbar kyphosis in pregnant women. Pregnancy may cause changes in spinal curvature and posture, which may in turn lead to relevant symptoms. Our data provide a basis for investigating the effects of spinal curvature and postural changes on symptoms during pregnancy. © 2012 The Authors Acta Obstetricia et Gynecologica Scandinavica© 2012 Nordic Federation of Societies of Obstetrics and Gynecology.

  9. Sequence periodicity in nucleosomal DNA and intrinsic curvature.

    Science.gov (United States)

    Nair, T Murlidharan

    2010-05-17

    Most eukaryotic DNA contained in the nucleus is packaged by wrapping DNA around histone octamers. Histones are ubiquitous and bind most regions of chromosomal DNA. In order to achieve smooth wrapping of the DNA around the histone octamer, the DNA duplex should be able to deform and should possess intrinsic curvature. The deformability of DNA is a result of the non-parallelness of base pair stacks. The stacking interaction between base pairs is sequence dependent. The higher the stacking energy the more rigid the DNA helix, thus it is natural to expect that sequences that are involved in wrapping around the histone octamer should be unstacked and possess intrinsic curvature. Intrinsic curvature has been shown to be dictated by the periodic recurrence of certain dinucleotides. Several genome-wide studies directed towards mapping of nucleosome positions have revealed periodicity associated with certain stretches of sequences. In the current study, these sequences have been analyzed with a view to understand their sequence-dependent structures. Higher order DNA structures and the distribution of molecular bend loci associated with 146 base nucleosome core DNA sequence from C. elegans and chicken have been analyzed using the theoretical model for DNA curvature. The curvature dispersion calculated by cyclically permuting the sequences revealed that the molecular bend loci were delocalized throughout the nucleosome core region and had varying degrees of intrinsic curvature. The higher order structures associated with nucleosomes of C.elegans and chicken calculated from the sequences revealed heterogeneity with respect to the deviation of the DNA axis. The results points to the possibility of context dependent curvature of varying degrees to be associated with nucleosomal DNA.

  10. Investigation of Virtual Digital Human and Robotic Device Technology Merger Complimented by Haptics and Autostereoscopic Displays, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — As expected, the STTR Phase I investigation confirmed that the Digital Virtual Human (DVH) and Robonaut technologies can be merged, and that haptic and...

  11. The role of curvature in silica mesoporous crystals

    KAUST Repository

    Miyasaka, Keiichi; Bennett, Alfonso Garcia; Han, Lu; Han, Yu; Xiao, Changhong; Fujita, Nobuhisa; Castle, Toen; Sakamoto, Yasuhiro; Che, Shunai; Terasaki, Osamu

    2012-01-01

    Silica mesoporous crystals (SMCs) offer a unique opportunity to study micellar mesophases. Replication of non-equilibrium mesophases into porous silica structures allows the characterization of surfactant phases under a variety of chemical and physical perturbations, through methods not typically accessible to liquid crystal chemists. A poignant example is the use of electron microscopy and crystallography, as discussed herein, for the purpose of determining the fundamental role of amphiphile curvature, namely mean curvature and Gaussian curvature, which have been extensively studied in various fields such as polymer, liquid crystal, biological membrane, etc. The present work aims to highlight some current studies devoted to the interface curvature on SMCs, in which electron microscopy and electron crystallography (EC) are used to understand the geometry of silica wall surface in bicontinuous and cage-type mesostructures through the investigation of electrostatic potential maps. Additionally, we show that by altering the synthesis conditions during the preparation of SMCs, it is possible to isolate particles during micellar mesophase transformations in the cubic bicontinuous system, allowing us to view and study epitaxial relations under the specific synthesis conditions. By studying the relationship between mesoporous structure, interface curvature and micellar mesophases using electron microscopy and EC, we hope to bring new insights into the formation mechanism of these unique materials but also contribute a new way of understanding periodic liquid crystal systems. © 2012 The Royal Society.

  12. The role of curvature in silica mesoporous crystals

    KAUST Repository

    Miyasaka, Keiichi

    2012-02-08

    Silica mesoporous crystals (SMCs) offer a unique opportunity to study micellar mesophases. Replication of non-equilibrium mesophases into porous silica structures allows the characterization of surfactant phases under a variety of chemical and physical perturbations, through methods not typically accessible to liquid crystal chemists. A poignant example is the use of electron microscopy and crystallography, as discussed herein, for the purpose of determining the fundamental role of amphiphile curvature, namely mean curvature and Gaussian curvature, which have been extensively studied in various fields such as polymer, liquid crystal, biological membrane, etc. The present work aims to highlight some current studies devoted to the interface curvature on SMCs, in which electron microscopy and electron crystallography (EC) are used to understand the geometry of silica wall surface in bicontinuous and cage-type mesostructures through the investigation of electrostatic potential maps. Additionally, we show that by altering the synthesis conditions during the preparation of SMCs, it is possible to isolate particles during micellar mesophase transformations in the cubic bicontinuous system, allowing us to view and study epitaxial relations under the specific synthesis conditions. By studying the relationship between mesoporous structure, interface curvature and micellar mesophases using electron microscopy and EC, we hope to bring new insights into the formation mechanism of these unique materials but also contribute a new way of understanding periodic liquid crystal systems. © 2012 The Royal Society.

  13. Studying biomolecule localization by engineering bacterial cell wall curvature.

    Directory of Open Access Journals (Sweden)

    Lars D Renner

    Full Text Available In this article we describe two techniques for exploring the relationship between bacterial cell shape and the intracellular organization of proteins. First, we created microchannels in a layer of agarose to reshape live bacterial cells and predictably control their mean cell wall curvature, and quantified the influence of curvature on the localization and distribution of proteins in vivo. Second, we used agarose microchambers to reshape bacteria whose cell wall had been chemically and enzymatically removed. By combining microstructures with different geometries and fluorescence microscopy, we determined the relationship between bacterial shape and the localization for two different membrane-associated proteins: i the cell-shape related protein MreB of Escherichia coli, which is positioned along the long axis of the rod-shaped cell; and ii the negative curvature-sensing cell division protein DivIVA of Bacillus subtilis, which is positioned primarily at cell division sites. Our studies of intracellular organization in live cells of E. coli and B. subtilis demonstrate that MreB is largely excluded from areas of high negative curvature, whereas DivIVA localizes preferentially to regions of high negative curvature. These studies highlight a unique approach for studying the relationship between cell shape and intracellular organization in intact, live bacteria.

  14. The speed-curvature power law of movements: a reappraisal.

    Science.gov (United States)

    Zago, Myrka; Matic, Adam; Flash, Tamar; Gomez-Marin, Alex; Lacquaniti, Francesco

    2018-01-01

    Several types of curvilinear movements obey approximately the so called 2/3 power law, according to which the angular speed varies proportionally to the 2/3 power of the curvature. The origin of the law is debated but it is generally thought to depend on physiological mechanisms. However, a recent paper (Marken and Shaffer, Exp Brain Res 88:685-690, 2017) claims that this power law is simply a statistical artifact, being a mathematical consequence of the way speed and curvature are calculated. Here we reject this hypothesis by showing that the speed-curvature power law of biological movements is non-trivial. First, we confirm that the power exponent varies with the shape of human drawing movements and with environmental factors. Second, we report experimental data from Drosophila larvae demonstrating that the power law does not depend on how curvature is calculated. Third, we prove that the law can be violated by means of several mathematical and physical examples. Finally, we discuss biological constraints that may underlie speed-curvature power laws discovered in empirical studies.

  15. Recruitment of Foveal Retinotopic Cortex During Haptic Exploration of Shapes and Actions in the Dark.

    Science.gov (United States)

    Monaco, Simona; Gallivan, Jason P; Figley, Teresa D; Singhal, Anthony; Culham, Jody C

    2017-11-29

    The role of the early visual cortex and higher-order occipitotemporal cortex has been studied extensively for visual recognition and to a lesser degree for haptic recognition and visually guided actions. Using a slow event-related fMRI experiment, we investigated whether tactile and visual exploration of objects recruit the same "visual" areas (and in the case of visual cortex, the same retinotopic zones) and if these areas show reactivation during delayed actions in the dark toward haptically explored objects (and if so, whether this reactivation might be due to imagery). We examined activation during visual or haptic exploration of objects and action execution (grasping or reaching) separated by an 18 s delay. Twenty-nine human volunteers (13 females) participated in this study. Participants had their eyes open and fixated on a point in the dark. The objects were placed below the fixation point and accordingly visual exploration activated the cuneus, which processes retinotopic locations in the lower visual field. Strikingly, the occipital pole (OP), representing foveal locations, showed higher activation for tactile than visual exploration, although the stimulus was unseen and location in the visual field was peripheral. Moreover, the lateral occipital tactile-visual area (LOtv) showed comparable activation for tactile and visual exploration. Psychophysiological interaction analysis indicated that the OP showed stronger functional connectivity with anterior intraparietal sulcus and LOtv during the haptic than visual exploration of shapes in the dark. After the delay, the cuneus, OP, and LOtv showed reactivation that was independent of the sensory modality used to explore the object. These results show that haptic actions not only activate "visual" areas during object touch, but also that this information appears to be used in guiding grasping actions toward targets after a delay. SIGNIFICANCE STATEMENT Visual presentation of an object activates shape

  16. Waterfall field in hybrid inflation and curvature perturbation

    International Nuclear Information System (INIS)

    Gong, Jinn-Ouk; Sasaki, Misao

    2011-01-01

    We study carefully the contribution of the waterfall field to the curvature perturbation at the end of hybrid inflation. In particular we clarify the parameter dependence analytically under reasonable assumptions on the model parameters. After calculating the mode function of the waterfall field, we use the δN formalism and confirm the previously obtained result that the power spectrum is very blue with the index 4 and is absolutely negligible on large scales. However, we also find that the resulting curvature perturbation is highly non-Gaussian and hence we calculate the bispectrum. We find that the bispectrum is at leading order independent of momentum and exhibits its peak at the equilateral limit, though it is unobservably small on large scales. We also present the one-point probability distribution function of the curvature perturbation

  17. Waterfall field in hybrid inflation and curvature perturbation

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Jinn-Ouk [Instituut-Lorentz for Theoretical Physics, Universiteit Leiden, 2333 CA Leiden (Netherlands); Sasaki, Misao, E-mail: jgong@lorentz.leidenuniv.nl, E-mail: misao@yukawa.kyoto-u.ac.jp [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan)

    2011-03-01

    We study carefully the contribution of the waterfall field to the curvature perturbation at the end of hybrid inflation. In particular we clarify the parameter dependence analytically under reasonable assumptions on the model parameters. After calculating the mode function of the waterfall field, we use the δN formalism and confirm the previously obtained result that the power spectrum is very blue with the index 4 and is absolutely negligible on large scales. However, we also find that the resulting curvature perturbation is highly non-Gaussian and hence we calculate the bispectrum. We find that the bispectrum is at leading order independent of momentum and exhibits its peak at the equilateral limit, though it is unobservably small on large scales. We also present the one-point probability distribution function of the curvature perturbation.

  18. Evolution of curvature perturbation in generalized gravity theories

    International Nuclear Information System (INIS)

    Matsuda, Tomohiro

    2009-01-01

    Using the cosmological perturbation theory in terms of the δN formalism, we find the simple formulation of the evolution of the curvature perturbation in generalized gravity theories. Compared with the standard gravity theory, a crucial difference appears in the end-boundary of the inflationary stage, which is due to the non-ideal form of the energy-momentum tensor that depends explicitly on the curvature scalar. Recent study shows that ultraviolet-complete quantum theory of gravity (Horava-Lifshitz gravity) can be approximated by using a generalized gravity action. Our paper may give an important step in understanding the evolution of the curvature perturbation during inflation, where the energy-momentum tensor may not be given by the ideal form due to the corrections from the fundamental theory.

  19. On the scalar curvature of self-dual manifolds

    International Nuclear Information System (INIS)

    Kim, J.

    1992-08-01

    We generalize LeBrun's explicit ''hyperbolic ansatz'' construction of self-dual metrics on connected sums of conformally flat manifolds and CP 2 's through a systematic use of the theory of hyperbolic geometry and Kleinian groups. (This construction produces, for example, all self-dual manifolds with semi-free S 1 -action and with either nonnegative scalar curvature or positive-definite intersection form.) We then point out a simple criterion for determining the sign of the scalar curvature of these conformal metrics. Exploiting this, we then show that the sign of the scalar curvature can change on connected components of the moduli space of self-dual metrics, thereby answering a question raised by King and Kotschick. (author). Refs

  20. CURVATURE-DRIVEN MOLECULAR FLOW ON MEMBRANE SURFACE.

    Science.gov (United States)

    Mikucki, Michael; Zhou, Y C

    2017-01-01

    This work presents a mathematical model for the localization of multiple species of diffusion molecules on membrane surfaces. Morphological change of bilayer membrane in vivo is generally modulated by proteins. Most of these modulations are associated with the localization of related proteins in the crowded lipid environments. We start with the energetic description of the distributions of molecules on curved membrane surface, and define the spontaneous curvature of bilayer membrane as a function of the molecule concentrations on membrane surfaces. A drift-diffusion equation governs the gradient flow of the surface molecule concentrations. We recast the energetic formulation and the related governing equations by using an Eulerian phase field description to define membrane morphology. Computational simulations with the proposed mathematical model and related numerical techniques predict (i) the molecular localization on static membrane surfaces at locations with preferred mean curvatures, and (ii) the generation of preferred mean curvature which in turn drives the molecular localization.