Showing papers in "IEEE Transactions on Haptics in 2010"

Noncontact Tactile Display Based on Radiation Pressure of Airborne Ultrasound

Abstract: This paper describes a tactile display which provides unrestricted tactile feedback in air without any mechanical contact. It controls ultrasound and produces a stress field in a 3D space. The principle is based on a nonlinear phenomenon of ultrasound: Acoustic radiation pressure. The fabricated prototype consists of 324 airborne ultrasound transducers, and the phase and intensity of each transducer are controlled individually to generate a focal point. The DC output force at the focal point is 16 mN and the diameter of the focal point is 20 mm. The prototype produces vibrations up to 1 kHz. An interaction system including the prototype is also introduced, which enables users to see and touch virtual objects.

Design of a Fingertip-Mounted Tactile Display with Tangential Skin Displacement Feedback

Abstract: Application of tangential skin displacement at the fingertip has been shown to be effective in communicating direction and has potential for several applications. We have developed a portable, fingertip-mounted tactile display capable of displacing and stretching the skin of the fingerpad, using a 7 mm hemispherical tactor. In vivo tests of fingerpad skin stiffness were performed to determine the forces required to effectively render stimuli. Other design parameters such as stimulus speed and displacement were derived from our earlier work. The tactile display is capable of rendering \pm 1 mm of displacement at arbitrary orientations within a plane and with rates of approximately 5 mm/s. Compliance and backlash in the device's drive train were characterized using external measurements, and were compensated for in software to reduce the impact on device hysteresis.

Review of Designs for Haptic Data Visualization

Abstract: 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.

ShiverPaD: A Glass Haptic Surface That Produces Shear Force on a Bare Finger

Abstract: We discuss the design and performance of a new haptic surface capable of controlling shear force on a bare finger. At the heart of the ShiverPaD is the TPaD variable friction device. It modulates the friction of a glass surface by using 39 kHz out-of-plane vibrations to reduce friction. To generate shear forces, the TPaD is oscillated in-plane (i.e., “shivered”) while alternating between low and high friction within each cycle. In previous research, the ShiverPaD produced shear forces using in-plane vibrations below 100 Hz. In this research, we develop a new ShiverPaD that produces force using 854 Hz vibrations, where human sensitivity to vibration is diminished. The new device is used to display a virtual toggle switch and a variety of virtual edges. A human subject study is conducted to demonstrate that users can easily trace virtual edges displayed on the surface of the ShiverPaD.

Finger-Shaped GelForce: Sensor for Measuring Surface Traction Fields for Robotic Hand

Abstract: It is believed that the use of haptic sensors to measure the magnitude, direction, and distribution of a force will enable a robotic hand to perform dexterous operations. Therefore, we develop a new type of finger-shaped haptic sensor using GelForce technology. GelForce is a vision-based sensor that can be used to measure the distribution of force vectors, or surface traction fields. The simple structure of the GelForce enables us to develop a compact finger-shaped GelForce for the robotic hand. GelForce that is developed on the basis of an elastic theory can be used to calculate surface traction fields using a conversion equation. However, this conversion equation cannot be analytically solved when the elastic body of the sensor has a complicated shape such as the shape of a finger. Therefore, we propose an observational method and construct a prototype of the finger-shaped GelForce. By using this prototype, we evaluate the basic performance of the finger-shaped GelForce. Then, we conduct a field test by performing grasping operations using a robotic hand. The results of this test show that using the observational method, the finger-shaped GelForce can be successfully used in a robotic hand.

Field-Based Validation of a Tactile Navigation Device

Abstract: In this paper, we present three field-based evaluations of a tactile land navigation system. In Experiment 1, we transition from a laboratory setting to rugged terrain used to train US Army soldier land navigation. Navigation in this challenging terrain requires careful attention to one's surroundings. Participants navigated 3 waypoints along 600 meters through heavily wooded terrain, using 1) map and compass, 2) standard alpha-numeric handheld GPS device, and 3) the tactile GPS system, while also responding to radio requests for information. Experiment 2 used the same challenging terrain during night operations, where participants must also search for live and silhouette targets, using 1) handheld GPS device, 2) head-mounted map-based GPS, and 3) the tactile GPS system. In addition to navigating, participants searched for silhouette and live (human) targets. Experiment 3 had participants navigate with 1) a commercial GPS arrow display, 2) the tactile GPS system, and 3) both together. We conclude that tactile navigation displays can be used in strenuous outdoor environments and can outperform visual displays under conditions of high cognitive and visual workload.

Bounded-Impedance Absolute Stability of Bilateral Teleoperation Control Systems

Abstract: Available passivity-based robust stability methods for bilateral teleoperation control systems are generally conservative, as they consider an unbounded range of dynamics for the class of passive operators and environments in the complex plane. In this paper, we introduce a powerful 3D geometrical robust stability analysis method based on the notions of wave variables and scattering parameters. The methodology, which was originally a 2D graphical method used in microwave systems for single-frequency analysis [1], is further developed in this paper for teleoperation and haptic systems. The proposed method provides both mathematical and visual aids to determine bounds or regions on the complex frequency response of the passive environment impedance parameters for which a potentially unstable system connected to any passive operator is stable, and vice-versa. Furthermore, the method allows for the design of bilateral controllers when such bounds are known, or can even be utilized when the environment dynamics are active. The geometrical test can also be replaced by an equivalent mathematical condition, which can easily be checked via a new stability parameter. The proposed method results in less conservative guaranteed stability conditions compared to the Llewellyn's criterion; thus, promising a better compromise between stability and performance. The new method is numerically evaluated for two bilateral control architectures.

Perception of Direction for Applied Tangential Skin Displacement: Effects of Speed, Displacement, and Repetition

Abstract: A variety of tasks could benefit from the availability of direction cues that do not rely on vision or sound. The application of tangential skin displacement at the fingertip has been found to be a reliable means of communicating direction and has potential to be rendered by a compact device. Our lab has conducted experiments exploring the use of this type of tactile stimulus to communicate direction. Each subject pressed his/her right index fingertip against a 7 mm rounded rubber cylinder that moved at constant speed, applying shear force to deform the skin of the fingerpad. A range of displacements (0.05-1 mm) and speeds (0.5-4 mm/s) were tested. Subjects were asked to respond with the direction of the skin stretch, choosing from four directions, each separated by 90 degrees. Direction detection accuracy was found to depend upon both the speed and total displacement of the stimulus, with higher speeds and larger displacements resulting in greater accuracy. Accuracy rates greater than 95 percent were observed with as little as 0.2 mm of tangential displacement and at speeds as slow as 1 mm/s. Results were analyzed for direction dependence and temporal trends. Subjects responded most accurately to stimuli in the proximal and distal directions, and least accurately to stimuli in the ulnar direction. Subject performance decreased slightly with prolonged testing but there was no statistically significant learning trend. A second experiment was conducted to evaluate priming effects and the benefit of repeated stimuli. It was found that repeated stimuli do not improve direction communication, but subject responses were found to have a priming effect on future performance. This preliminary information will inform the design and use of a tactile display suitable for use in hand-held electronics.

Rendering Softness: Integration of Kinesthetic and Cutaneous Information in a Haptic Device

Abstract: While it is known that softness discrimination relies on both kinesthetic and cutaneous information, relatively little work has been done on the realization of haptic devices replicating the two cues in an integrated and effective way. In this paper, we first discuss the ambiguities that arise in unimodal touch, and provide a simple intuitive explanation in terms of basic contact mechanics. With this as a motivation, we discuss the implementation and control of an integrated device, where a conventional kinesthetic haptic display is combined with a cutaneous softness display. We investigate the effectiveness of the integrated display via a number of psychophysical tests and compare the subjective perception of softness with that obtained by direct touch on physical objects. Results show that the subjects interacting with the integrated haptic display are able to discriminate softness better than with either a purely kinesthetic or a purely cutaneous display.

Rotational Skin Stretch Feedback: A Wearable Haptic Display for Motion

Abstract: We present a wearable haptic feedback device that imparts rotational skin stretch to the hairy skin, along with the results of psychophysical tests to determine its resolution and accuracy for motion display. Tracking experiments with visual markers reveal the pattern of skin motion and strain imparted by the device, confirming subjective impressions that the design represents a trade-off between perception at low stimulus levels and comfort at maximum stimulus levels. In an isolated environment, users were able to discriminate between different rotational displacements of stretch within two to five degrees, depending on the reference stimulus. In a more realistic setting, subjects were able to use feedback from the device to control the positioning of a virtual object within six degrees or ±6.5 degrees of the total range of motion. When subjects were passive and exposed to arbitrary rotations of the device, the accuracy was poorer, although it improved with training. The results suggest that wearable skin stretch devices can be an effective means of providing feedback about a user's controlled joint or limb motions for motion training and similar applications.

Combination and Integration in the Perception of Visual-Haptic Compliance Information

Abstract: The compliance of a material can be conveyed through mechanical interactions in a virtual environment and perceived through both visual and haptic cues. We investigated this basic aspect of perception. In two experiments, subjects performed compliance discriminations, and the mean perceptual estimate (PSE) and the perceptual standard deviation (proportional to JND) were derived from psychophysical functions. Experiment 1 supported a model in which each modality acted independently to produce a compliance estimate, and the two estimates were then integrated to produce an overall value. Experiment 2 tested three mathematical models of the integration process. The data ruled out exclusive reliance on the more reliable modality and stochastic selection of one modality. Instead, the results supported an integration process that constitutes a weighted summation of two random variables, which are defined by the single modality estimates. The model subsumes optimal fusion but provided valid predictions also if the weights were not optimal. Weights were optimal (i.e., minimized variance) when vision and haptic inputs were congruent, but not when they were incongruent.

Optimum Information Transfer Rates for Communication through Haptic and Other Sensory Modalities

Abstract: This paper is concerned with investigating the factors that contribute to optimizing information transfer (IT) rate in humans With an increasing interest in designing complex haptic signals for a wide variety of applications, there is a need for a better understanding of how information can be displayed in an optimal way Based on the results of several early studies from the 1950s, a general “rule of thumb” has arisen in the literature which suggests that IT rate is dependent primarily on the stimulus delivery rate and is optimized for presentation rates of 2-3 items/s Thus, the key to maximizing IT rate is to maximize the information in the stimulus set Recent data obtained with multidimensional tactual signals, however, appear to contradict these conclusions In particular, these current results suggest that optimal delivery rate varies with stimulus information to yield a constant peak IT rate that depends on the degree of familiarity and training with a particular stimulus set We discuss factors that may be responsible for the discrepancies in results across studies including procedural differences, training issues, and stimulus-response compatibility These factors should be taken into account when designing haptic signals to yield optimal IT rates for communication devices

New Magnetic Microactuator Design Based on PDMS Elastomer and MEMS Technologies for Tactile Display

Abstract: Highly efficient tactile display devices must fulfill technical requirements for tactile stimulation, all the while preserving the lightness and compactness needed for handheld operation. This paper focuses on the elaboration of highly integrated magnetic microactuators for tactile display devices. FEM simulation, conception, fabrication, and characterization of these microactuators are presented in this paper. The current demonstrator offers a 4 × 4 flexible microactuator array with a resolution of 2 mm. Each actuator is composed of a Poly (Dimethyl-Siloxane) (PDMS) elastomeric membrane, magnetically actuated by coil-magnet interaction. It represents a proof of concept for fully integrated MEMS tactile devices, with fair actuation forces provided for a power consumption up to 100 mW per microactuator. The prototypes are destined to provide both static and dynamic tactile sensations, with an optimized membrane geometry for actuation frequencies between DC and 350 Hz. On the basis of preliminary experiments, this display device can offer skin stimulations for various tactile stimuli for applications in the fields of Virtual Reality or Human-Computer Interaction (HCI). Moreover, the elastomeric material used in this device and its global compactness offer great advantages in matter of comfort of use and capabilities of integration in haptic devices.

A Frequency-Domain Analysis of Haptic Gratings

Abstract: The detectability and discriminability of virtual haptic gratings were analyzed in the frequency domain. Detection (Exp. 1) and discrimination (Exp. 2) thresholds for virtual haptic gratings were estimated using a force-feedback device that simulated sinusoidal and square-wave gratings with spatial periods from 0.2 to 38.4 mm. The detection threshold results indicated that for spatial periods up to 6.4 mm (i.e., spatial frequencies >0.156 cycle/mm), the detectability of square-wave gratings could be predicted quantitatively from the detection thresholds of their corresponding fundamental components. The discrimination experiment confirmed that at higher spatial frequencies, the square-wave gratings were initially indistinguishable from the corresponding fundamental components until the third harmonics were detectable. At lower spatial frequencies, the third harmonic components of square-wave gratings had lower detection thresholds than the corresponding fundamental components. Therefore, the square-wave gratings were detectable as soon as the third harmonic components were detectable. Results from a third experiment where gratings consisting of two superimposed sinusoidal components were compared (Exp. 3) showed that people were insensitive to the relative phase between the two components. Our results have important implications for engineering applications, where complex haptic signals are transmitted at high update rates over networks with limited bandwidths.

Effects of Packet Loss and Latency on the Temporal Discrimination of Visual-Haptic Events

Abstract: Temporal discontinuities and delay caused by packet loss or communication latency often occur in multimodal telepresence systems. It is known that such artifacts can influence the feeling of presence [1]. However, it is largely unknown how the packet loss and communication latency affect the temporal perception of multisensory events. In this article, we simulated random packet dropouts and communication latency in the visual modality and investigated the effects on the temporal discrimination of visual-haptic collisions. Our results demonstrated that the synchronous perception of crossmodal events was very sensitive to the packet loss rate. The packet loss caused the impression of time delay and influenced the perception of the subsequent events. The perceived time of the visual event increased linearly, and the temporal discrimination deteriorated, with increasing packet loss rate. The perceived time was also influenced by the communication delay, which caused time to be slightly overestimated.

Vibrotactile Feedback for Information Delivery in the Vehicle

Abstract: As technology advances, more functions have been, and continue to be added to the vehicle, resulting in increased needs for improved user interfaces. In this paper, we investigate the feasibility of using vibrotactile feedback for in-vehicle information delivery. First, we measured the spectral characteristics of ambient vibrations in a vehicle, and designed clearly distinguishable sinusoidal vibrations. We further selected via dissimilarity rating the four sets of sinusoidal vibrations which had three to six vibrations. Second, we evaluated the learnability of the vibration sets when associated with common menu items of a Driver Information System (DIS). We also replaced the two most confused sinusoidal vibrations with patterned messages, and assessed the degree of learnability improvement. Finally, we evaluated the extent to which participants could select a desired function in a DIS via vibrotactile messages while simultaneously performing a driving-like primary task with higher priority. The results demonstrated high potential for vibrotactile messages to be effectively used for the communicative transfer of in-vehicle system information.

Design of Dynamic Vibrotactile Textures

Abstract: This paper describes a method for creating virtual textures without force feedback by using a simple motion sensor and a single vibrotactile actuator. It is based on wavetable synthesis driven by the user's hand movements. The output of the synthesis is rendered with the tactile actuator attached in a hand-held box together with the motion sensor. The method provides a solution for creating tangible properties for virtual objects which can be explored by pointing at them with the sensor-actuator device. The study introduces 12 virtual textures which were based on three different envelope ridge lengths, two spatial densities, and were either regularly or irregularly organized. To evaluate the role of each design parameter in the perception of the texture, a series of experiments was conducted. The perceived similarity was assessed in a pairwise comparison test and the outcome was analyzed by using multidimensional scaling. The analysis revealed that envelope ridge length and spatial density were distinguishable design parameters while regularity was not. The textures were also rated according to five attribute scales previously determined in the pilot experiment. The results show that ridge length and spatial density influence perceived roughness and flatness similarly as with real textures.

Perceived Vibration Strength in Mobile Devices: The Effect of Weight and Frequency

Abstract: This paper addresses the question of strength perception for vibration signals used in mobile devices. Employing devices similar to standard cell phones and using pulsed vibration signals to combat adaptation effects, experiments were performed to study the effect of weight and underlying on perceived strength. Results shows that for the same measured acceleration on the device, a heavier box is perceived to vibrate with greater strength. Furthermore, signals with higher underlying frequency are perceived to be weaker for the same measured acceleration. While our results are consistent with previous studies, they are obtained for the specific condition of ungrounded, vibrating objects held in the hand. Our results suggest the need for a systematic correction law for use by designers to specify the vibratory characteristics of a device as a function of its weight and of the desired operating frequency.

The Effect of Augmented Feedback on Grasp Force in Laparoscopic Grasp Control

Abstract: Little is known about the influence of augmented feedback, on laparoscopic grasp control. To gain more knowledge on the influence of this on the learning curve, two experiments were conducted. In the first experiment, four groups learned a single-handed laparoscopic lifting task. Three groups received augmented feedback (visual, haptic, or a combination of feedback modes) on slip and excessive pinch force. In the second experiment, a two-handed task had to be accomplished to investigate whether paying reduced attention would influence grasp-force control. The surgeons and novices either received tactile feedback or no augmented feedback on grasp forces. In both experiments, learning sessions and a retention test followed a pretest. In the two-handed task, novices who received tactile feedback could control their pinch force in order to remain within the required limits unlike participants who did not receive augmented feedback. Approximately, one-third of the participants who received augmented feedback became dependent on the signal. Regardless of their level of experience, participants benefited from augmented feedback. This research supports the claim that there is a need for augmented tactile feedback when learning laparoscopic grasp control. It enhances learning and goes beyond what could be achieved without.

A Parallel Computing Platform for Real-Time Haptic Interaction with Deformable Bodies

Abstract: Real-time simulation of haptic interaction with deformable objects is computationally demanding. In particular in finite-element (FE) based analysis of such interactions, a large system of equations must be solved at an update rate of 100-1,000 Hz for simulation fidelity and stability. A new hardware-based parallel implementation of a Preconditioned Conjugate Gradient (PCG) algorithm is proposed for solving the linear systems of equations arising from FE-based deformation models. Concurrent utilization of a large number of fixed-point computing units on a Field-Programmable Gate Array (FPGA) device yields a very fast solution to these equations. Quantization and overflow errors in the fixed-point implementation of the iterative solver are minimized through dynamic scaling and preconditioning. Numerical accuracy of the solution, the architecture design, and issues pertaining to the degree of parallelism and scalability of the architecture are discussed in detail. The implementation of the solver on an Altera EP3SE110 FPGA device has enabled real-time simulation of three-dimensional linear elastic deformation models with 1,500 nodes at an update rate of up to 2,500 Hz.

When Content Matters: The Role of Processing Code in Tactile Display Design

Abstract: The distribution of tasks and stimuli across multiple modalities has been proposed as a means to support multitasking in data-rich environments. Recently, the tactile channel and, more specifically, communication via the use of tactile/haptic icons have received considerable interest. Past research has examined primarily the impact of concurrent task modality on the effectiveness of tactile information presentation. However, it is not well known to what extent the interpretation of iconic tactile patterns is affected by another attribute of information: the information processing codes of concurrent tasks. In two driving simulation studies (n = 25 for each), participants decoded icons composed of either spatial or nonspatial patterns of vibrations (engaging spatial and nonspatial processing code resources, respectively) while concurrently interpreting spatial or nonspatial visual task stimuli. As predicted by Multiple Resource Theory, performance was significantly worse (approximately 5-10 percent worse) when the tactile icons and visual tasks engaged the same processing code, with the overall worst performance in the spatial-spatial task pairing. The findings from these studies contribute to an improved understanding of information processing and can serve as input to multidimensional quantitative models of timesharing performance. From an applied perspective, the results suggest that competition for processing code resources warrants consideration, alongside other factors such as the naturalness of signal-message mapping, when designing iconic tactile displays. Nonspatially encoded tactile icons may be preferable in environments which already rely heavily on spatial processing, such as car cockpits.

Visually Guided Haptic Search

Abstract: In this study, we investigate the influence of visual feedback on haptic exploration. A haptic search task was designed in which subjects had to haptically explore a virtual display using a force-feedback device and to determine whether a target was present among distractor items. Although the target was recognizable only haptically, visual feedback of finger position or possible target positions could be given. Our results show that subjects could use visual feedback on possible target positions even in the absence of feedback on finger position. When there was no feedback on possible target locations, subjects scanned the whole display systematically. When feedback on finger position was present, subjects could make well-directed movements back to areas of interest. This was not the case without feedback on finger position, indicating that showing finger position helps to form a spatial representation of the display. In addition, we show that response time models of visual serial search do not generally apply for haptic serial search. Consequently, in teleoperation systems, for instance, it is helpful to show the position of the probe even if visual information on the scene is poor.

Interconnection and Simulation Issues in Haptics

Abstract: In this paper, three results are presented concerning certain computational/control aspects, crucial for the proper behavior of haptic devices. The first one is a novel technique for a real-time simulation of virtual environments, which is able to preserve the energetic behavior of the simulated physical system and to avoid undesired effects related to unstable behaviors of the haptic device. The proposed real-time integration method is simpler, in terms of computational complexity, than similar solutions known in the literature, and provides an additional insight when “faulty conditions” are met. Second, a new method for the energy-consistent interconnection of discrete-time physical systems, implemented by algorithms running at different frequencies (i.e., multirate systems), is illustrated. Multirate systems are very common in haptics, since the frequency, at which the control law of the haptic interface is executed, is usually higher than the frequency of the simulation of the virtual environment. Finally, the third result presented in this paper concerns the problem of energy generation due to the time discretization in the acquisition of the haptic interface position. Similarly, to the previous case, a technique for an energy-consistent analog/digital conversion is proposed. All these methodologies have been validated, both by simulations and experiments.

A model for sharing haptic interaction

Abstract: In this paper, we present new methods for sharing haptic interactions with other persons when touching real-world objects. Unlike the previous approaches, our system does not rely on a virtual model of the object being explored or the integration of visual/auditory modalities to augment the user's perception. We developed a prototype system that makes it possible to capture active haptic interactions on a transmitting side, and then, display them passively to a receiving side. To demonstrate the concept, we conducted human experiments using rubber samples and found that the relationship between the haptic sensations of the transmitting and receiving sides follows a power function, and the parameters of this function can be calibrated for the users of the system.

Haptic Object Individuation

Abstract: Item individuation, i.e., how we decide which parts belong to one object and which to another, is an important aspect of haptic perception and may be important for design of interfaces in which different buttons have to be distinguished. We daily hold several objects in our hand. Somehow, we decide that we are holding several small objects instead of one large object. We aim to provide insight into how it is decided that some parts belong to the same object and others to a different object, i.e., object individuation. This process may be influenced by heterogeneity of size or shape of the handled objects. To investigate this, subjects were asked to grasp varying numbers of shapes together in the hand and respond fast and accurately the number of shapes. We compared performance for a set of homogeneous objects (Experiment 1) to performance for sets of objects heterogeneous in size (Experiment 2) or shape (Experiment 3). It was found that numerosity judgments in terms of response times, error rates, and object handling were similar in all three experiments. We conclude that size and shape features that are used for object recognition do not play a role in item individuation.

Haptic Classification of Facial Identity in 2D Displays: Configural versus Feature-Based Processing

Abstract: Participants learned through feedback to haptically classify the identity of upright versus inverted versus scrambled faces depicted in simple 2D raised-line displays. We investigated whether identity classification would make use of a configural face representation, as is evidenced for vision and 3D haptic facial displays. Upright and scrambled faces produced equivalent accuracy, and both were identified more accurately than inverted faces. The mean magnitude of the haptic inversion effect for 2D facial identity was a sizable 26 percent, indicating that the upright orientation was ?privileged? in the haptic representations of facial identity in these 2D displays, as with other facial modalities. However, given the effect of scrambling, we conclude that configural processing was not employed; rather, only local information about the features was used, the features being treated as oriented objects within a body-centered frame of reference. The results indicate a fundamental difference between haptic identification of 2D facial depictions and 3D faces, paralleling a corresponding difference in recognition of nonface objects.

An Interview with Susan Lederman

Abstract: Presents an interview with Susan Lederman, retiring Associate Editor-in-Chief of IEEE Transactions on Haptics.

Guest Editorial for World Haptics Spotlight Section

Abstract: The five papers in this special section are extended versions of papers that were presented at the World Haptics conference in Salt Lake City, Utah, in March 2009.