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We fabricated a soft thin-film vibrotactile actuator, which can be easily inserted into wearable devices, based on an electroactive PVC gel. One of the most important factors in fabricating a soft and thin vibrotactile actuator is to create vibrational force strong enough to stimulate human skin in a wide frequency range. To achieve this, we investigate the working principle of the PVC gel and suggest a new structure in which most of electric energy contributes to the deformation of the PVC gel. Due to this structure, the vibrational amplitude of the proposed PVC gel actuator could considerably increase (0.816 g (g = 9.8 m/s²) at resonant frequency). The vibrotactile amplitude is proportional to the amount of input voltage. It increased from 0.05 g up to 0.416 g with increasing applied voltages from 200 V to 1 kV at 1 Hz. The experimental results show that the proposed actuator can create a variety of haptic sensations. [ABSTRACT FROM AUTHOR]

The integration of polymeric actuators in haptic displays is widespread nowadays, especially in virtual reality and rehabilitation applications. However, we are still far from optimizing the transducer ability in conveying sensory information. Here, we present a vibrotactile actuator characterized by a piezoelectric disk embedded in a polydimethylsiloxane (PDMS) shell. An original encapsulation technique was performed to provide the stiff active element with a compliant cover as an interface towards the soft human skin. The interface stiffness, together with the new geometry, generated an effective transmission of vibrotactile stimulation and made the encapsulated transducer a performant component for the development of wearable tactile displays. The mechanical behavior of the developed transducer was numerically modeled as a function of the driving voltage and frequency, and the exerted normal forces were experimentally measured with a load cell. The actuator was then tested for the integration in a haptic glove in single-finger and bi-finger condition, in a 2-AFC tactile stimulus recognition test. Psychophysical results across all the tested sensory conditions confirmed that the developed integrated haptic system was effective in delivering vibrotactile information when the frequency applied to the skin is within the 200-700 Hz range and the stimulus variation is larger than 100 Hz. [ABSTRACT FROM AUTHOR]

A squeeze film induced by ultrasonic vibration between two solid surfaces in contact can dramatically reduce the friction between them. This phenomenon, so-called the squeeze film effect, has been utilized in variable friction tactile displays for texture rendering purposes. Such tactile displays can provoke a haptic sensation to a finger pad in a controllable way. A real-time adjustment of the coefficient of lateral friction between the human finger pad and the tactile display can be accomplished by modulating the vibration amplitude of the tactile panel. Therefore, driving a reliable friction model is a key step towards designing and controlling tactile displays utilizing the squeeze film effect. This paper derives a modified Herschel- Bulkley rheological model to express the lateral friction exerted on a human fingertip via an air squeeze film as a function of the operating parameters such as the driving voltage amplitude, the finger sliding speed, and the contact pressure. In contrast to the conventional Coulomb friction model, such a rheology model can account for the sliding velocity dependence. This modeling work may contribute to the optimal control of the ultrasonic variable friction tactile displays. [ABSTRACT FROM AUTHOR]

Tactile displays can present virtual tactile sensations to the user by stimulating tactile receptors, which are distributed spatially within the skin and are classified into four types based on their characteristic temporal pattern of impulses. The mechanotactile displays can stimulate different types of the receptors selectively by changing the displacement and frequency of the skin deformation. In our previous work, we developed an array of large-displacement microactuators composed of hydraulic amplification mechanism (HDAM) and piezoelectric actuators, which is capable of stimulating all the four types of the tactile receptors. We controlled the driving parameters that were the driving voltage, vibration frequency, and actuation patterns of the actuators, and successfully presented various surface textures. However, in practical applications, the control parameters are to be tuned according to the surface textures that we want to present. In addition, the input signals to the piezoelectric actuators would consist of multiple frequency components and are difficult to create through trial and errors. To solve this inverse problem, in this work, we encoded the sample surface textures to voltage signals by sliding the sample over the HDAM and using the piezoelectric actuators as sensors. First, we attempted to reproduce the surface textures. The encoded signals were amplified to drive the mechanotactile display. The perception tests indicated that this approach was effective. Secondly, we attempted to correlate the encoded signals with hardness of the samples. The encoded signals were investigated among the samples of different hardness. In addition, we fabricated moicropatterned tactile samples that have the same physical properties except Young’s modulus to isolate hardness from other parameters. The encoded signals were compared to extract the characteristic signals to determine the hardness. These signals were used to drive the tactile display in the perception tests, which verified the effectiveness of the approach. These two approaches that were proposed and experimentally verified in this paper are readily applicable to solve the inverse problem in tactile display applications. [ABSTRACT FROM AUTHOR]

The present paper describes a thin and flexible electrotactile display having an array of microneedle electrodes that present tactile sensation on the forearm in a two-dimensional manner at low voltages. Tactile displays elicit tactile sensation by artificially stimulating tactile receptors. Electrotactile displays stimulate tactile receptors electrically and can be designed to be thin, light, and flexible, and therefore wearable. We developed an electrotactile display having microneedle electrodes that penetrate the high-impedance stratum corneum, thereby decreasing the threshold voltage to provide tactile sensation. Stimulation at a point and in a line was successfully demonstrated in our prior work. In this paper, we demonstrate an electrotactile display that can present tactile sensation in a plane with two-dimensionally distributed microneedle electrodes. The display is expected to increase the variety of tactile sensation and the amount of available information. We conducted experiments to determine the optimal gap between the microneedles to efficiently present a plane-like sensation. When the gap is too large, the subjects do not perceive a plane-like tactile sensation but only point-like stimulations at the electrodes, whereas the small gap leads to difficulties in manufacturing. A gap of 3 mm was experimentally found to be optimal. Using the manufactured electrotactile display, smooth/rough sensation in a plane was successfully presented on the forearm. [ABSTRACT FROM AUTHOR]

This paper presents a handheld surgical tool adapting a tactile feedback system. The tool consists of a 3-degree-of-freedom (DOF) force sensor and three tactile displays. The sensor is easily embedded in the tool by adopting the capacitive transduction principle. The sensor measures the direction and magnitude of the 3-DOF force applied to the tool tip. The fingertip grasping the tool is stimulated by the tactile display to transmit the contact force information measured by the sensor. The tactile display is actuated by employing a soft actuator technology based on a dielectric elastomer actuator such as a type of electroactive polymer actuator. In this work, a prototype of the tool is designed and fabricated. Its performance is experimentally validated. [ABSTRACT FROM AUTHOR]

Haptic Jamming, the approach of simultaneously controlling mechanical properties and surface deformation of a tactile display via particle jamming and pneumatics, shows promise as a tangible, shape-changing human-computer interface. Previous research introduced device design and described the force-displacement interactions for individual jamming cells. The work in this article analyzes the shape output capabilities of a multi-cell array. A spring-mass deformable body simulation combines models of the three actuation inputs of a Haptic Jamming surface: node pinning, chamber pressurization, and cell jamming. Surface measurements of a 12-cell prototype from a depth camera fit the mass and stiffness parameters to the device during pressurization tests and validate the accuracy of the model for various actuation sequences. The simulator is used to develop an algorithm that generates a sequence of actuation inputs for a Haptic Jamming array of any size in order to match a desired surface output shape. Data extracted from topographical maps and three-dimensional solid object models are used to evaluate the shape-matching algorithm and assess the utility of increasing array size and resolution. Results show that a discrete Laplace operator applied to the input is a suitable predictor of the correlation coefficient between the desired shape and the device output. [ABSTRACT FROM PUBLISHER]

We investigate the accuracy with which the haptic sharpness perception of a virtual edge is matched to that of a real edge and the effect of the virtual surface stiffness on the match. The perceived sharpness of virtual edges was estimated in terms of the point of subjective equality (PSE) when participants matched the sharpness of virtual edges to that of real edges with a radius of 0.5, 2.5, and 12.5 mm over a virtual stiffness range of 0.6 to 3.0 N/mm. The perceived sharpness of a real and a virtual edge of the same radius was significantly different under all but one of the experimental conditions and there was a significant effect of virtual surface stiffness on the accuracy of the match. The results suggest that the latter is presumably due to a constant penetration force employed by the participants that influenced the penetration depth and perceived sharpness of virtual edges at different surface stiffness levels. Our findings provide quantitative relations for appropriately offsetting the radii of virtual edges in order to achieve the desired perceived sharpness of virtual edges. [ABSTRACT FROM PUBLISHER]

We present a driving concept of a tactile actuator based on a dielectric electroactive polymer using a ring-type electrode. This electrode is located around a deflectable membrane. The fabrication process and tests of the tactile actuator including integration into a hydraulic amplifier design are presented proving the concept of the novel actuation. The tactile actuator exhibits a maximum measured deflection of 124±7 μm for an applied voltage of 4200 V. The membrane thickness and the total thickness of the actuator including hydraulic amplifier were 30 and about 570 μm, respectively. [ABSTRACT FROM AUTHOR]

Humans constantly process and integrate sensory input from multiple sensory modalities. However, the amount of input that can be processed is constrained by limited attentional resources. A matter of ongoing debate is whether attentional resources are shared across sensory modalities, and whether multisensory integration is dependent on attentional resources. Previous research suggested that the distribution of attentional resources across sensory modalities depends on the the type of tasks. Here, we tested a novel task combination in a dual task paradigm: Participants performed a self-terminated visual search task and a localization task in either separate sensory modalities (i.e., haptics and vision) or both within the visual modality. Tasks considerably interfered. However, participants performed the visual search task faster when the localization task was performed in the tactile modality in comparison to performing both tasks within the visual modality. This finding indicates that tasks performed in separate sensory modalities rely in part on distinct attentional resources. Nevertheless, participants integrated visuotactile information optimally in the localization task even when attentional resources were diverted to the visual search task. Overall, our findings suggest that visual search and tactile localization partly rely on distinct attentional resources, and that optimal visuotactile integration is not dependent on attentional resources.

Recently, electrovibration tactile displays were studied and applied to several use cases by researchers. The high-resolution electrode for electrovibration stimulus will contribute to the presentation of a more realistic tactile sensation. However, the sizes of the electrodes that have been used thus far are of the millimeter-order. In this study, we evaluated whether a single narrow electrode was able to provide the electrovibration stimulus adequately. The widths of the prepared electrodes were 10, 20, 50, 100, 200, and 500 μm. We conducted a sensory experiment to characterize each electrode. The electrodes with widths of 50 μm or less were not durable or suitable for the applied signal, although the subjects perceived the stimulus. Therefore, we conducted the experiment without using these non-durable electrodes. The voltage waveform condition affected perception, and the subjects were not sensitive to the electrovibration stimulus at low frequencies. In addition, the stroke direction of the fingertip had a significant effect on perception under certain conditions. The results indicate that electrovibration stimulation requires an electrode with a width of only a few hundred micrometers for stimulation.

This paper presents a novel, wearable navigation system for visually impaired and blind pedestrians that combines a global positioning system (GPS) for user outdoor localization and tactile-foot stimulation for information presentation. Real-time GPS data provided by a smartphone are processed by dedicated navigation software to determine the directions to a destination. Navigational directions are then encoded as vibrations and conveyed to the user via a tactile display that inserts into the shoe. The experimental results showed that users were capable of recognizing with high accuracy the tactile feedback provided to their feet. The preliminary tests conducted in outdoor locations involved two blind users who were guided along 380–420 m predetermined pathways, while sharing the space with other pedestrians and facing typical urban obstacles. The subjects successfully reached the target destinations. The results suggest that the proposed system enhances independent, safe navigation of blind pedestrians and show the potential of tactile-foot stimulation in assistive devices.

We have developed a hydraulic displacement amplification mechanism (HDAM) and studied its dynamic response when combined with a piezoelectric actuator. The HDAM consists of an incompressible fluid sealed in a microcavity by two largely deformable polydimethylsiloxane (PDMS) membranes. The geometry with input and output surfaces having different cross-sectional areas creates amplification. By combining the HDAM with micro-actuators, we can amplify the input displacement generated by the actuators, which is useful for applications requiring large deformation, such as tactile displays. We achieved a mechanism offering up to 18-fold displacement amplification for static actuation and 12-fold for 55 Hz dynamic actuation.

As the largest organ in the human body, the skin provides the important sensory channel for humans to receive external stimulations based on touch. By the information perceived through touch, people can feel and guess the properties of objects, like weight, temperature, textures, and motion, etc. In fact, those properties are nerve stimuli to our brain received by different kinds of receptors in the skin. Mechanical, electrical, and thermal stimuli can stimulate these receptors and cause different information to be conveyed through the nerves. Technologies for actuators to provide mechanical, electrical or thermal stimuli have been developed. These include static or vibrational actuation, electrostatic stimulation, focused ultrasound, and more. Smart materials, such as piezoelectric materials, carbon nanotubes, and shape memory alloys, play important roles in providing actuation for tactile sensation. This paper aims to review the background biological knowledge of human tactile sensing, to give an understanding of how we sense and interact with the world through the sense of touch, as well as the conventional and state-of-the-art technologies of tactile actuators for tactile feedback delivery.

A friction-variable touch panel is capable of presenting virtual bumps and holes on its flat surface through the control of the surface friction when a fingertip slides over it. To improve the presentation, we developed a friction model of a fingertip sliding over a sinusoidal surface with an amplitude of 0.5–2.5 mm and a spatial wavelength of 20–50 mm. When a metal ball rolls over a wavy surface with a low friction and contact area, the ratio of the horizontal force to the normal force is equal to the gradient of the surface (this is referred to as the ball bearing model) and is hardly affected by the normal load and rolling speed. In contrast, the profile of the force ratio of a sliding finger is substantially skewed and affected by the sliding direction and normal force exerted by the finger. To model this skewed force ratio, we formulated the asymmetric pressure distribution in the finger-surface contact area and used the effects of the adhesion friction to model the dependency of the force ratio on the normal force and sliding direction. The developed model of a bare finger with these features was found to sufficiently simulate the experimentally observed force ratios. The model can be easily applied to friction-variable touch panels and enables the achievement of a wide variety of haptic contents with macroscopically concave or convex surfaces. [ABSTRACT FROM PUBLISHER]

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Tactile vision substitution devices are assistive devices for the blind that redirect visual information to the skin. The amount of visual information that can be presented on a tactile display is limited mainly by the spatial resolution of the skin and the ability to distinguish between various vibration intensities. In this study, we have determined the two-point discrimination (TPD) threshold and intensity-discrimination threshold (just-noticeable difference, or JND) on the lower back using coin motors. Given the importance of stimulus timing, we have determined TPD threshold and JND at different stimulus onset asynchronies (SOAs). The JND was determined between two coin motors with a distance equal to the TPD threshold. In this way, we could establish the contrast sensitivity at the maximal theoretical resolution. TPD thresholds tended to decrease at longer SOAs, from 52 mm edge-to-edge at an SOA of 0 ms, to 28 mm at 200 ms. The JND did not depend on SOA, and the average Weber fraction was 0.14. A median of 5 JNDs was available across the available dynamic range. Together, these data provide the predicted spatial resolution and contrast resolution achievable with a back-worn tactile display based on coin motors. [ABSTRACT FROM PUBLISHER]

To enhance virtual reality (VR) generated by tactile displays, we have focused on a novel tactile illusion, called the Velvet Hand Illusion (VHI). In VHI, moving two parallel wires back and forth between the two hands leads humans to perceive a velvet-like surface between their hands. In earlier studies, we revealed that the intensity of VHI could be controlled by a ratio (r/D), where r and D are the wire stroke and wire distance, respectively. According to these findings, we investigate in this study whether a common tactile display is able to produce VHI, and whether the ratio can also control VHI intensity. We prepare a dot-matrix display as a tactile display in which moving one line of the display's pins is considered as a wire pattern. We investigate the VHI intensity with regard to changing the stroke r and the line distance D using paired comparison. Experimental results show that the VHI intensity is increased or decreased by changing r and D. We conclude that VHI can be created by the tactile display, and the intensity of VHI is controlled by changing the ratio of r/D. [ABSTRACT FROM AUTHOR]

Electronic Travel Aids (ETAs) improve the mobility of visually-impaired persons, but it is not easy to develop an ETA satisfying all the factors needed for reliable object detection, effective notification, and actual usability. In this study, the authors developed an easy-to-use ETA having the function of reliable object detection and its successful feedback to the user by tactile stimulation. Seven ultrasonic sensors facing in different directions detect obstacles in the walking path, while vibrators in the tactile display stimulate the hand according to the distribution of obstacles. The detection of ground drop-offs activates the electromagnetic brakes linked to the rear wheels. To verify the feasibility of the developed ETA in the outdoor environment, walking tests by blind participants were performed, and the evaluation of safety to ground drop-offs was carried out. From the experiment, the feasibility of the developed ETA was shown to be sufficient if the sensor ranges for hanging obstacle detection is improved and learning time is provided for the ETA. Finally, the light-weight and low cost ETA designed and assembled based on the evaluation of the developed ETA is introduced to show the improvement of portability and usability, and is compared with the previously developed ETAs. [ABSTRACT FROM AUTHOR]

Sensory augmentation operates by synthesizing new information then displaying it through an existing sensory channel and can be used to help people with impaired sensing or to assist in tasks where sensory information is limited or sparse, for example, when navigating in a low visibility environment. This paper presents the design of a 2nd generation head-mounted vibrotactile interface as a sensory augmentation prototype designed to present navigation commands that are intuitive, informative, and minimize information overload. We describe an experiment in a structured environment in which the user navigates along a virtual wall whilst the position and orientation of the user's head is tracked in real time by a motion capture system. Navigation commands in the form of vibrotactile feedback are presented according to the user's distance from the virtual wall and their head orientation. We test the four possible combinations of two command presentation modes (continuous, discrete) and two command types (recurring, single). We evaluated the effectiveness of this ‘tactile language’ according to the users’ walking speed and the smoothness of their trajectory parallel to the virtual wall. Results showed that recurring continuous commands allowed users to navigate with lowest route deviation and highest walking speed. In addition, subjects preferred recurring continuous commands over other commands. [ABSTRACT FROM PUBLISHER]

This paper describes the control in a (d-q) frame of the vibration amplitude of a tactile stimulator based on ultrasonic vibrations. The goal is to fulfill simultaneously two objectives: maintain a constant level of the vibration amplitude and excite the system at the resonance frequency. A new modeling approach is presented in order to facilitate the control and to fulfill the two objectives simultaneously. Then, thanks to an experimental setup, the validation of the new model is performed. Finally, the result of the closed-loop control over a wide range of disturbing factors is presented. [ABSTRACT FROM PUBLISHER]

In joint tasks, adjusting to the actions of others is critical for success. For joint visual search tasks, research has shown that when search partners visually receive information about each other’s gaze, they use this information to adjust to each other’s actions, resulting in faster search performance. The present study used a visual, a tactile and an auditory display, respectively, to provide search partners with information about each other’s gaze. Results showed that search partners performed faster when the gaze information was received via a tactile or auditory display in comparison to receiving it via a visual display or receiving no gaze information. Findings demonstrate the effectiveness of tactile and auditory displays for receiving task-relevant information in joint tasks and are applicable to circumstances in which little or no visual information is available or the visual modality is already taxed with a demanding task such as air-traffic control. Practitioner Summary: The present study demonstrates that tactile and auditory displays are effective for receiving information about actions of others in joint tasks. Findings are either applicable to circumstances in which little or no visual information is available or when the visual modality is already taxed with a demanding task. [ABSTRACT FROM AUTHOR]

Humans constantly process and integrate sensory input from multiple sensory modalities. However, the amount of input that can be processed is constrained by limited attentional resources. A matter of ongoing debate is whether attentional resources are shared across sensory modalities, and whether multisensory integration is dependent on attentional resources. Previous research suggested that the distribution of attentional resources across sensory modalities depends on the the type of tasks. Here, we tested a novel task combination in a dual task paradigm: Participants performed a self-terminated visual search task and a localization task in either separate sensory modalities (i.e., haptics and vision) or both within the visual modality. Tasks considerably interfered. However, participants performed the visual search task faster when the localization task was performed in the tactile modality in comparison to performing both tasks within the visual modality. This finding indicates that tasks performed in separate sensory modalities rely in part on distinct attentional resources. Nevertheless, participants integrated visuotactile information optimally in the localization task even when attentional resources were diverted to the visual search task. Overall, our findings suggest that visual search and tactile localization partly rely on distinct attentional resources, and that optimal visuotactile integration is not dependent on attentional resources. [ABSTRACT FROM AUTHOR]

Vibrotactile collision warning signals that create a sensation of motion across a driver's body result in faster brake reaction times (BRTs) to potential collision events. To date, however, such warnings have only simulated linear motion. We extended this research by exploring the effectiveness of collision warnings that incorporate vibrotactile patterns or “vibrotactile flow”. In Experiment 1, expanding and contracting vibrotactile flow warnings were compared with a static warning (all tactors activated simultaneously) and a no warning condition in a car following scenario. Both vibrotactile flow warnings produced significantly faster BRTs than the static and no warning conditions. However, there was no directional effect. That is, there was no significant difference between contracting and expanding signals. Warnings that utilize vibrotactile flow therefore appear to provide an effective means of informing drivers about potential collision events. However, unlike comparable warnings utilizing linear motion, their effectiveness does not seem to depend on the precise relationship between the warning and collision events. Experiment 2 demonstrated that a tactile warning incorporating linear motion produced significantly faster BRTs than an expanding vibrotactile flow warning. Taken together, these results suggest that vibrotactile warnings that simulate linear motion may be more effective than vibrotactile flow warnings. [ABSTRACT FROM PUBLISHER]

We provide supplemental data to a vibrator array tactile display, as well as additional data for application of the edge stimulation (ES) method proposed in our previous study. By vibrating two surfaces in different phases and touching their boundary, a strong continuous line sensation, not on the vibrators themselves, but along the boundary, is obtained. This vibrotactile edge is suitable for presenting virtual lines, areas, and shapes on a rigid flat surface. We investigated the fundamental performance of the ES method through psychophysical experiments. The effects on the vibrotactile detection thresholds were investigated for three mechanical parameters, i.e., the vibratory frequency, the phase difference between the vibrations, and the gap distance between adjoining vibratory surfaces. Two-line discrimination thresholds for lines presented by the ES method were also determined. We found that the detection thresholds under the ES method was lower than 10 $\mu$ m even at the low frequencies (lower than 50 Hz), which is significantly lower than that under simply touching to a single vibratory surface. A comparison of the perceived widths revealed that the ES method provides a more localized tactile image than a single-pin vibrator or a flat-top vibrator. A 3 $\times$ 3 vibrator array display was developed using the ES method based on the properties obtained from the experiments. Seven categories of display patterns were presented with the ES array display and the participants’ responses matched at 95 percent. [ABSTRACT FROM PUBLISHER]

The growing complexity of telemanipulation tasks calls for increased realism and intuitiveness of the interaction between the user and the master control. Humans perceive multiple haptic features of an object such as its stiffness, temperature, and shape, and rely on this multimodal information to achieve dexterous manipulation. However, to date, remote manipulators rarely provide haptic information to the operator. Moreover, current multimodal displays are often too rigid and bulky to be integrated into the manipulator. Thus, to improve the quality of teleoperation, there is a high demand for flexible devices that are capable of matching the skin's curvature while delivering multimodal haptic information to the operator. In this paper, we present a flexible tactile display delivering tactile and thermal stimuli to the user’s skin. We propose a hybrid electromagnetic-pneumatic actuation to operate a 2 × 2 array of tactile cells. Each cell provides a repetitive stimulation with a force and an indentation that are above the human perception threshold for the finger, palm, and forearm. In addition, the temperature of the display’s surface is controlled using a Peltier element attached to an air-cooled heatsink. By providing a reproducible cooling gradient, our display simulates common materials encountered in the daily environment. User study results show that (1) the tactile stimulation is perceived well and (2) the identification rates of objects simulated with the display were comparable to those obtained with real objects. Unlike previous devices, the thermal stimulation is delivered while the display is in constant contact with the user’s skin, a necessary requirement for teleoperation. These results demonstrate the potential of our device as a promising tactile display for providing haptic feedback in teleoperation. [ABSTRACT FROM AUTHOR]

This paper proposes a novel method of manipulating both thermal change rate and thermal intensity to convey colour information by using a thermal tactile display. The colourspace transformation from {red, green, blue} to {hue, saturation, intensity} is introduced, and the mapping between colour and temperature is established based on warm and cold colours. Considering the lower resolution of the tactile channel, six limited stimulation levels are generated to represent colours. Based on the semi-infinite body model, the thermal response within the skin for each stimulation form is investigated. The Peltier element of the display is designed to convey different thermal stimuli to the human finger. Two experiments are performed to evaluate the performance of the display: colour identification and discrimination. Experimental results indicate that there is a response bias among the perceived colours for the traditional method of only employing thermal intensity, but there is no response bias for the proposed method; subjects' mean recognition accuracy with the proposed method is significantly higher than that gained using the traditional method. Furthermore, colour information of the captured images can be reliably discriminated by using this devised thermal tactile display. [ABSTRACT FROM AUTHOR]

The tactile display is a device which physically stimulates the human skin to reproduce the feel of touch. This paper presents a novel tactile display device driven by a dielectric elastomer actuator. The device adopts an indirect actuation method by using a rigid coupling, which aims to avoid direct contact of the human skin with the actuator. The rigid coupling is made of silicone to transmit the movement of the actuator to the touch layer located on the top surface of the coupling and provides the feeling of softness on contact. The device produces displacement about 350-140 μm at 0.3-10 Hz, which meets frequency requirements for simulating the Merkel cells as well as Meissner corpuscle. The force to simulate the fingertips can be exerted over 44 mN. This work describes its design, analysis and fabrication method in details with its experimental evaluations. [ABSTRACT FROM AUTHOR]