Noncontact Tactile Display Based on Radiation Pressure of Airborne Ultrasound

Midair Haptic Pursuit

In human vision, smooth pursuit eye movement is the basic ability to visually follow a moving object by keeping it at the sight center. In this study, we validate that a human hand has a similar ability to track a midair haptic stimulus, i.e., a human palm exposed to a point vibration by a noncontact ultrasound tactile display can follow the continuous movement of the stimulation point. The experimental results show that the trackable velocity limit is 10 cm/s for motion parallel to the palm, when the initial velocity is zero. This ability of motion tracking by hand can be applied to haptic guidance for visually impaired people or for evacuation navigation, where no devices are needed to be equipped by users.

Method of localized removal of cells using a bolt-clamped Langevin transducer with an ultrasonic horn

Cell isolation by eliminating undesirable cell aggregations or colonies with low activity is essential to improve cell culture efficiency. Moreover, when creating tissues from induced pluripotent stem cells, residual undifferentiated cells must be removed to prevent tumor formation in vivo. Here, we evaluated the use of ultrasonic irradiation, which can apply energy locally without contact, and proposed a method to eliminate cells in a small area of culture by ultrasonic irradiation from a Langevin transducer. We constructed a device that incorporated a bolt-clamped 19.84 kHz Langevin transducer with an ultrasonic horn and determined the optimal conditions for stable elimination of cells in small areas of a 35-mm culture dish. The optimal conditions were as follows: number of cycles = 400, clearance distance = 1 mm, volume of medium = 4 mL, and distance from the center of culture surface = 0 mm. The mean cell elimination area under these conditions was 0.097 mm². We also evaluated the viability of neighboring cells after ultrasonic irradiation by fluorescent staining and found that most cells around the elimination area survived. These findings suggest that the proposed method has potential for localized elimination of cells without the need for contact with the cell surface.

Fundamental Perceptual Characterization of an Integrated Tactile Display with Electrovibration and Electrical Stimuli

Tactile displays have been widely studied for many decades. Although multiple tactile stimuli are more effective to improve the quality of the presented tactile sensation, most tactile displays provide a single tactile stimulus. An integrated tactile display with electrovibration and electrical stimuli is proposed herein. It is expected that vibrational friction, pressure and vibration can be presented at the same time through the tactile display. Also, these stimuli only require electrodes for stimulation. Therefore, the tactile display can be easily miniaturized and densely arrayed on a substrate. In this study, a tactile display is designed and fabricated using the micro-fabrication process. Furthermore, the display is evaluated. First, the relationship between a single stimulus and the perception is investigated. The electrovibration and electrical stimuli have a frequency dependence on perception. Second, whether the multiple stimuli with the electrovibration and electrical stimuli are perceivable by the subjects is also evaluated. The results indicate that the multiple tactile stimuli are perceivable by the subjects. Also, the possibility that the electrovibration and electrical stimuli affect each other is confirmed.

Modulating Fine Roughness Perception of Vibrotactile Textured Surface using Pseudo-haptic Effect

Playing back vibrotactile signals through actuators is commonly used to simulate tactile feelings of virtual textured surfaces. However, there is often a small mismatch between the simulated tactile feelings and intended tactile feelings by tactile designers. Thus, a method of modulating the vibrotactile perception is required. We focus on fine roughness perception and we propose a method using a pseudo-haptic effect to modulate fine roughness perception of vibrotactile texture. Specifically, we visually modify the pointer's position on the screen slightly, which indicates the touch position on textured surfaces. We hypothesized that if users receive vibrational feedback watching the pointer visually oscillating back/forth and left/right, users would believe the vibrotactile surfaces more uneven. We also hypothesized that as the size of visual oscillation is getting larger, the amount of modification of roughness perception of vibrotactile surfaces would be larger. We conducted user studies to test the hypotheses. Results of first user study suggested that users felt vibrotactile texture with our method rougher than they did without our method at a high probability. Results of second user study suggested that users felt different roughness for vibrational texture in response to the size of visual oscillation. These results confirmed our hypotheses and they suggested that our method was effective. Also, the same effect could potentially be applied to the visual movement of virtual hands or fingertips when users are interacting with virtual surfaces using their hands.

INTERACTION EFFECT BETWEEN BEAM DIAMETER AND ENERGY DENSITY IN LASER-INDUCED TACTILE PERCEPTION

This study aims to investigate the interaction effect between the beam diameter and energy density, which are perceived as laser-induced tactile perception by humans, by diversely varying the laser parameters, beam diameter, and energy. Eight healthy male college students of 23.5[Formula: see text][Formula: see text][Formula: see text]1.7 years participated in the study. The range of the beam diameter of the displayed laser stimulation was between 0.03[Formula: see text]mm and 8[Formula: see text]mm, and a total of 21 sizes were displayed. The laser energy was sequentially displayed from the minimum energy that can be displayed by one beam diameter to the maximum energy range that does not exceed the maximum permissible exposure (MPE) level since the energy varies according to the beam diameter. The laser energy was controlled by an optical density ([Formula: see text]) filter and was measured by an optical power meter (energy meter). Furthermore, the beam diameter was adjusted by moving the lens, which was confirmed with the beam profiler. The experimental test consists of the control phase (19[Formula: see text]s), stimulus phase (7[Formula: see text]s), and response phase (4[Formula: see text]s); the total duration of the test was 30[Formula: see text]s. The stimulus phase is the period in which stimulation was displayed on the skin through laser irradiation, and the stimulation was displayed by changing the beam diameter and the energy from the laser. The total number of beam diameter and energy pairs displayed to the subjects was 113 and 5 trials of irradiation were conducted for each pair. Stimulation perception response was recorded by pressing the response buttons during the response phase, and the responses were predefined as “no feeling,” “tactile sensation”, and “pain.” Through the extracted response data from the response phase, the beam diameter and energy density pair in which more than 50% of the subjects responded as having perceived tactile sensation were selected from the possible laser energy that could be displayed from one beam diameter. The simulation results showed that increasing the beam diameter increased the penetration depth, indicating an effective energy transfer to the skin. Therefore, increasing the beam diameter results in increased scattering, and hence increased penetration depth, and ultimately a more effective energy transfer. Therefore, increased beam diameter results in higher energy transfer efficiency, indicating that the required energy density by more than 50% of the subjects to perceive tactile sensation decreased.

Uncertainty analysis on free-field reciprocity calibration of measurement microphones for airborne ultrasound

Airborne ultrasound has been used for various purposes, including object detection and pest repellent systems. Recently, it has been used in haptic technology for virtual reality. The safety of exposure to airborne ultrasound has been studied as its use has increased. Although airborne ultrasound cannot be directly perceived by humans, some research has found that exposure to very high sound pressure levels can harm the human body. Thus, quantitative characterization of airborne ultrasound is essential. To contribute to the safe use of airborne ultrasound, this paper established the acoustic standards in Japan in terms of sound pressure from 20 to 100 kHz. This paper evaluates the measurement uncertainty in the free-field reciprocity calibration of quarter-inch condenser microphones, following the document "Guide to the Expression of Uncertainty in Measurement," and describes a few significant uncertainty components, such as deviation from the plane sound field. As a result, it is realized that the expanded uncertainty of 0.3-0.7 dB in a frequency range from 20 to 100 kHz.

Somatosensory Evoked Responses Elicited by Haptic Sensations in Midair

The design of human-machine interfaces (HMIs) by virtual haptics is an emerging field of research. So far, the perception of virtual haptic feedback, e.g., generated by focused ultrasound in midair has not been objectively evaluated. This paper demonstrates the feasibility of eliciting somatosensory evoked potentials (SEPs) with ultrasonic stimuli in midair for the first time. The palm was stimulated by short ultrasonic focal points generated by an ultrasound board. The results are compared with a no stimulation condition as well as with the results of a vibro tactile stimulation. The SEPs are analyzed with the wavelet phase synchronization stability (WPSS) and the M-consecutive averaged WPSS. The results indicate a clear SEP waveform elicited by ultrasound. It can be significantly differentiated from a no stimulation condition by the M-consecutive averaged WPSS. These results could enable the possibility of developing an objective evaluation method for virtual haptic feedback in HMIs.

Development of a Fully Flexible Sheet-Type Tactile Display Based on Electrovibration Stimulus

Tactile displays have been extensively studied for several decades. However, owing to their bulkiness and stiffness, it has been difficult to integrate these displays with information devices to enable tactile communication between the devices and their users. This paper proposes a novel sheet-type electrovibration tactile display that consists of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate conductive layers and an insulation layer of polydimethylsiloxane. The tactile display is sufficiently thin and flexible for attaching onto various surfaces. In this study, the tactile display was micro-fabricated and characterized through experiments. The experimental results indicated that the tactile display exhibited good durability under bending and that it could present various tactile sensations depending on the type of voltage waveform. In addition, the effect of using a combination of electrovibration and thermal stimuli was also demonstrated. The sheet-type display was attached onto a Peltier element; the thinness of the structure enabled the display to conform to the element and ensure good heat transfer. In the experiment, subjects were asked to scan the display with their fingertips. The results showed that multiple tactile stimuli were also successfully perceived by the subjects.

Shape Localization and Recognition Using a Magnetorheological-Fluid Haptic Display

Smart materials such as magnetorheological fluids (MRF) offer an interesting technology for use in haptic displays as changes in the magnetic field are rapid, reversible, and controllable. These interfaces have been evaluated in a number of medical and surgical simulators where they can provide cues regarding the viscoelastic properties of tissues. The objective of the present set of experiments was first to determine whether a shape embedded in the MRF could be precisely localized and second whether 10 shapes rendered in a MRF haptic display could be accurately identified. It was also of interest to determine how the information transfer associated with this type of haptic display compares to that achieved using other haptic channels of communication. The overall performance of participants at identifying the shapes rendered in the MRF was good with a mean score of 73 percent correct and an Information Transfer (IT) of 2.2 bits. Participants could also localize a rigid object in the display accurately. These findings indicate that this technology has potential for use in training manual palpation skills and in exploring haptic shape perception in dynamic environments.

Aerial Vibrotactile Display Based on MultiUnit Ultrasound Phased Array

In this paper, we report on an airborne vibrotactile display with a multiunit ultrasound phased array synthetic aperture. The system generates an ultrasound field with a location-tunable focus in the air, which exerts time-variant acoustic radiation pressure on the user's skin, resulting in perceivable localized vibrotactile stimuli. The paper contains three major new contributions from previous related works. The first is an experimental validation of large-aperture focusing with improved synchronization offering an enlarged workspace in which sufficient acoustic power concentration is guaranteed. From the experiments, it is expected that perceivable vibrotactile focus can be generated 1 m away from a four-unit array system. The second is an experimental evaluation of the presented pressure for producing a broad variety of tactile perception, which shows that the generated ultrasound focus can serve as an vibrotactile actuator that has flat frequency characteristics in the domain of perceptual stimuli. The third is a psychophysical result of the detection threshold curve for sinusoidal stimuli offered by the system. The obtained curve shows similarity with conventionally known results, which have minimum values at approximately 200 Hz.

Midair Ultrasound Fragrance Rendering

We propose a system that controls the spatial distribution of odors in an environment by generating electronically steerable ultrasound-driven narrow air flows. The proposed system is designed not only to remotely present a preset fragrance to a user, but also to provide applications that would be conventionally inconceivable, such as: 1) fetching the odor of a generic object placed at a location remote from the user and guiding it to his or her nostrils, or 2) nullifying the odor of an object near a user by carrying it away before it reaches his or her nostrils (Fig. 1). These are all accomplished with an ultrasound-driven air stream serving as an airborne carrier of fragrant substances. The flow originates from a point in midair located away from the ultrasound source and travels while accelerating and maintaining its narrow cross-sectional area. These properties differentiate the flow from conventional jet- or fan-driven flows and contribute to achieving a midair flow. In our system, we employed a phased array of ultrasound transducers so that the traveling direction of the flow could be electronically and instantaneously controlled. In this paper, we describe the physical principle of odor control, the system construction, and experiments conducted to evaluate remote fragrance presentation and fragrance tracking.

Luciola

In this paper, we present an approach to realize the levitation of a small object with an embedded electronic circuit. Luciola is a light-emitting particle with a diameter of 3.5mm and a weight of 16.2mg moving in mid-air in a 10.4cm x 10.4cm x 5.4cm space through acoustic levitation using two 40-kHz 17 x 17 ultrasonic transducer arrays placed face-to-face at a distance of 20cm and wirelessly powered by 12.3-MHz resonant inductive coupling. The novelty of this paper is the acoustically levitated electronic object by the combined application of ultrasonic levitation and wireless powering to the levitated electronic object. A new shape of the levitated object and a new placement of the receiver coil to simultaneously realize acoustic levitation and wireless powering are proposed, achieving a stable wireless powering to a rotating levitated object at the bottom of an acoustic potential. To enable the levitation of a particle, a custom IC chip is essential in reducing the size and weight of the particle. In the design of the custom IC chip, a new voltage detector circuit enabling an accurate voltage detection and a correct output during the start-up is proposed to achieve an intermittent lighting of the LED to increase the maximum distance between the transmitter and the receiver coil. Luciola is applied to a self-luminous pixel in a mid-air display and drawings of characters in mid-air are demonstrated.

SpiroSurface: A Repulsive and Attractive Force Display for Interactive Tabletops Using a Pneumatic System

We present SpiroSurface, a novel force display for interactive tabletops. SpiroSurface uses a pneumatic system to generate both repulsive and attractive forces. We develop a prototype with 5x5 grid holes on the surface connected to an air compressor and vacuum tanks through electromagnetic valves. The display can output a maximum of +1.0 and -0.08 megapascal (MPa) pressure from a hole that generates 74 and -6 N force. We investigated the latency of the output pressure through pneumatics and an experiment, which indicated a minimum of 50-ms latency. The display allows the creation of three kinds of novel interactions: (1) enhancement of GUI, (2) deformation of soft objects, and (3) three-degree-of-freedom rotation of objects. In the first application, users can feel the force from the display without holding or attaching additional devices. In the second and third applications, the shape and motion of an object on the surface can be manipulated without embedding additional active components in the objects. These aspects allow users to easily experience interaction and expand the freedom of interaction design. We introduce several examples combining video projection and motion tracking. These examples demonstrate the potential of the display.

Ultraino: An Open Phased-Array System for Narrowband Airborne Ultrasound Transmission

Modern ultrasonic phased-array controllers are electronic systems capable of delaying the transmitted or received signals of multiple transducers. Configurable transmit-receive array systems, capable of electronic steering and shaping of the beam in near real-time, are available commercially, for example, for medical imaging. However, emerging applications, such as ultrasonic haptics, parametric audio, or ultrasonic levitation, require only a small subset of the capabilities provided by the existing controllers. To meet this need, we present Ultraino, a modular, inexpensive, and open platform that provides hardware, software, and example applications specifically aimed at controlling the transmission of narrowband airborne ultrasound. Our system is composed of software, driver boards, and arrays that enable users to quickly and efficiently perform research in various emerging applications. The software can be used to define array geometries, simulate the acoustic field in real time, and control the connected driver boards. The driver board design is based on an Arduino Mega and can control 64 channels with a square wave of up to 17 Vpp and /5 phase resolution. Multiple boards can be chained together to increase the number of channels. The 40-kHz arrays with flat and spherical geometries are demonstrated for parametric audio generation, acoustic levitation, and haptic feedback.

TinyLev: A multi-emitter single-axis acoustic levitator

Acoustic levitation has the potential to enable novel studies due to its ability to hold a wide variety of substances against gravity under container-less conditions. It has found application in spectroscopy, chemistry, and the study of organisms in microgravity. Current levitators are constructed using Langevin horns that need to be manufactured to high tolerance with carefully matched resonant frequencies. This resonance condition is hard to maintain as their temperature changes due to transduction heating. In addition, Langevin horns are required to operate at high voltages (>100 V) which may cause problems in challenging experimental environments. Here, we design, build, and evaluate a single-axis levitator based on multiple, low-voltage (ca. 20 V), well-matched, and commercially available ultrasonic transducers. The levitator operates at 40 kHz in air and can trap objects above 2.2 g/cm³ density and 4 mm in diameter whilst consuming 10 W of input power. Levitation of water, fused-silica spheres, small insects, and electronic components is demonstrated. The device is constructed from low-cost off-the-shelf components and is easily assembled using 3D printed sections. Complete instructions and a part list are provided on how to assemble the levitator.

A Wearable Encounter-Type Haptic Device Suitable for Combination with Visual Display

[abstFig src='/00280006/02.jpg' width='260' text='The encounter type wearable haptic device' ] This paper describes a wearable encounter-type haptic device suitable for combined usage with a visual display. The features of the device lie in a driving mechanism that enables an encounter-type haptic display and the compact implementation of the entire device including the driving mechanism. The driving mechanism displays a natural haptic sense based on a smooth transition between follow-up and constraint of finger movements. The compactness is important because it contributes to preserving the quality of visual information when used together with a visual display. To test the basic performance of the device, the response of the driving mechanism was evaluated. The haptic display function was evaluated by a simulation in which the device is used to touch an object in a computer graphics (CG) space.

Mid-Air Tactile Stimulation Using Indirect Laser Radiation

In this paper, we demonstrate that a laser irradiated on a thin light-absorbing elastic medium attached on the skin can elicit a tactile sensation of mechanical tap. First, we present simulation results that show laser irradiation to the elastic medium creates inner elastic waves on the basis of thermoelastic effects and these elastic waves trigger the bending deformation of the medium, which then stimulates the skin. Second, we analyze the physical properties of the associated stimulus by measuring its force profile. Third, we identify the perceptual characteristics of the stimulus in comparison to those of mechanical and electrical stimuli by means of a perceptual experiment employing dissimilarity rating. All the evidence indicates that indirect laser radiation provides a sensation of short mechanical tap. Furthermore, little individual difference was observed in the results of the perceptual experiment. To the best of our knowledge, this study is the first in reporting the feasibility of indirect laser radiation for mid-air tactile rendering.

Presentation of Various Tactile Sensations Using Micro-Needle Electrotactile Display

Tactile displays provoke tactile sensations by artificially stimulating tactile receptors. While many types of tactile displays have been developed, electrotactile displays that exploit electric stimulation can be designed to be thin, light, flexible and thus, wearable. However, the high voltages required to stimulate tactile receptors and limited varieties of possible sensations pose problems. In our previous work, we developed an electrotactile display using a micro-needle electrode array that can drastically reduce the required voltage by penetrating through the high-impedance stratum corneum painlessly, but displaying various tactile sensations was still a challenge. In this work, we demonstrate presentation of tactile sensation of different roughness to the subjects, which is enabled by the arrangement of the electrodes; the needle electrodes are on the fingertip and the ground electrode is on the fingernail. With this arrangement, the display can stimulate the tactile receptors that are located not only in the shallow regions of the finger but also those in the deep regions. It was experimentally revealed that the required voltage was further reduced compared to previous devices and that the roughness presented by the display was controlled by the pulse frequency and the switching time, or the stimulation flow rate. The proposed electrotactile display is readily applicable as a new wearable haptic device for advanced information communication technology.

UltraPulse--simulating a human arterial pulse with focussed airborne ultrasound

Medical simulators provide a risk-free environment for trainee doctors to practice and improve their skills. UltraPulse is a new tactile system designed to utilise focussed airborne ultrasound to mimic a pulsation effect such as that of a human arterial pulse. In this paper, we focus on the construction of the haptics component, which can later be integrated into a variety of medical procedure training simulators.

Displaying shape haptically using MRF-based device

Smart materials such as magnetorheological fluids (MRF) offer an interesting medium to present viscoelastic cues in haptic displays as changes in the magnetic field are rapid, reversible and controllable. These interfaces have been evaluated in a number of medical and surgical simulators where they can provide cues regarding the viscoelastic properties of tissues. The present experiment determined whether eight different shapes could be identified reliably with a MRF haptic display and compared the information transfer (IT) associated with this type of display with that achieved by other forms of haptic communication. The overall performance of participants at identifying the shapes was good with a mean score of 70% correct and an IT of 2.13 bits. This type of display shows promise as a training tool for simulating tissue properties.

Evaluation of the possibility and response characteristics of laser-induced tactile sensation

In this study, we examined the possibility and perceptual response characteristics of tactile sense induced by laser stimulation to the finger with different laser energy densities through human response experiments. 15 healthy adult males and 4 healthy adult females with an age of 22.6±2.2 years were tested. A frequency-doubled Q-switched laser was used with a wavelength of 532 nm and a 5 ns pulse width. The experimental trial spanned a total of 30 s and included a rest phase (19 s), a stimulation phase (7 s), and a response phase (4 s). During the rest phase, subjects kept their fingers comfortable. During the stimulation phase, one of three types of laser energy density (13.5, 16.6, 19.8 mJ/cm(2)) or a sham stimulation was used to irradiate the distal phalanx on the right index finger. During the response phase, the cognitive response to the laser stimulation was recorded by a PC by pressing the response button. The confusion matrix was configured to evaluate the possibility that the tactile sense was caused by the laser. In addition, changes in the response characteristics were observed according to three types of laser energy densities. From the analysis of the confusion matrix, the accuracy and sensitivity were not high. In contrast, precision and specificity were found to be high. Furthermore, there was a strong positive correlation between the laser irradiation and tactile perception, indicating that tactile sense can be induced using a laser in a mid-air manner. In addition, it was found that as the laser energy density increased, the tactile perception possibility also increased.

Laser-induced thermoelastic effects can evoke tactile sensations

Humans process a plethora of sensory information that is provided by various entities in the surrounding environment. Among the five major senses, technology for touch, haptics, is relatively young and has relatively limited applications largely due to its need for physical contact. In this article, we suggest a new way for non-contact haptic stimulation that uses laser, which has potential advantages such as mid-air stimulation, high spatial precision, and long working distance. We demonstrate such tactile stimulation can be enabled by laser-induced thermoelastic effects by means of physical and perceptual studies, as well as simulations. In the physical study, the mechanical effect of laser on a human skin sample is detected using low-power radiation in accordance with safety guidelines. Limited increases (< ~2.5 °C) in temperature at the surface of the skin, examined by both thermal camera and the Monte Carlo simulation, indicate that laser does not evoke heat-induced nociceptive sensation. In the human EEG study, brain responses to both mechanical and laser stimulation are consistent, along with subjective reports of the non-nociceptive sensation of laser stimuli.

Localized Tactile Feedback on a Transparent Surface through Time-Reversal Wave Focusing

This article addresses the problem of producing independent tactile stimuli to multiple fingers exploring a transparent solid surface without the need to track their positions. To this end, wave time-reversal was applied to re-focus displacement impulses in time and in space at one or several locations in a thin glass plate. This result was achieved using ultrasonic bending waves produced by a set of lamellar piezoelectric actuators bonded at the periphery of the plate. Starting from first principles, the relations linking implementation parameters to the performance of the display are developed. The mechanical design of the display, signal processing, and driving electronics are described. A set of engineering tradeoffs are made explicit and used for the design of a mock up device comprising a glass plate 148 × 210 × 0.5 mm (3). Tests indicate that a peak amplitude of 7 &#956m confined to a 20 mm (2) region could be obtained for an average power consumption of 45 mW. Simultaneous focusing at several locations was successfully achieved. We showed that a lumped-mass model for the fingertip can effectively describe the effect of an actual fingertip load at the focus point. Lastly, we elucidated a likely stimulation mechanism that involves the transient decoupling of the finger skin from the plate surface. This phenomenon explains the observed tactile effect.

The colloidal metamorphosis: time division multiplexing of the reflectance state

Specular reflection plays an important role in an image's appearance. However, LCDs don't have sufficient contrast to express specular reflection, and ordinary projector screens only have diffuse-reflection surfaces. A new display system projects ultrasound waves to dynamically change the reflection state of a screen made of a colloidal substance--soap film. The system uses time division multiplexing of the diffuse and specular states to produce realistic appearances. It employs an optical illusion that exploits the characteristics of human sight. Optical measurements and a user study validated this approach's effectiveness.

Three-dimensional mid-air acoustic manipulation by ultrasonic phased arrays

The essence of levitation technology is the countervailing of gravity. It is known that an ultrasound standing wave is capable of suspending small particles at its sound pressure nodes. The acoustic axis of the ultrasound beam in conventional studies was parallel to the gravitational force, and the levitated objects were manipulated along the fixed axis (i.e. one-dimensionally) by controlling the phases or frequencies of bolted Langevin-type transducers. In the present study, we considered extended acoustic manipulation whereby millimetre-sized particles were levitated and moved three-dimensionally by localised ultrasonic standing waves, which were generated by ultrasonic phased arrays. Our manipulation system has two original features. One is the direction of the ultrasound beam, which is arbitrary because the force acting toward its centre is also utilised. The other is the manipulation principle by which a localised standing wave is generated at an arbitrary position and moved three-dimensionally by opposed and ultrasonic phased arrays. We experimentally confirmed that expanded-polystyrene particles of 0.6 mm, 1 mm, and 2 mm in diameter could be manipulated by our proposed method.

Enhancing audiovisual experience with haptic feedback: a survey on HAV

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.