Tactile technologies are important for novel user experiences. Among several tactile submodalities, cold sensation is essential for realistically portraying materials and environments. However, current cold presentations such as Peltier devices face challenges like low energy efficiency and the need for complicated equipment. To address these, we suggest leveraging alcohol’s endothermic property during evaporation. Our prototype, a wristwatch wearable with a fan, capitalizes on alcohol’s high volatility by absorbing ambient heat upon evaporation. The device further enhances the cooling effect by circulating air around the skin. This approach simplifies the setup required for cooling technologies and is more energy-efficient than Peltier-based systems. We also integrated perfume, which is a mixture of alcohol and scent substance, and presented a unique cooling and scent experience. The use of alcohol as a cooling method was not considered conventional, but social changes after COVID-19 made it easy to obtain a tiny amount of alcohol.

In virtual environments, rapid and accurate perception of object shapes is critical for achieving skillful interactions and enhancing immersion. Typically, conventional force feedback devices that provide force direction and magnitude across the entire finger faces challenges in accurately representing fine geometric details of object shapes, such as edges. To address this issue, we augmented force feedback devices with a compact and high-density cutaneous electrical stimulation mechanism, aiming to improve the representation of subtle shapes. In the evaluation experiments, reactive force and edge cues for virtual objects were simultaneously presented, and shape discrimination tests were conducted on four types of column shapes with a thickness of 7.5 mm. Comparing force feedback-only, cutaneous feedback-only, and their combination conditions, our results demonstrated that the combined approach improved shape discrimination accuracy, confirming a more precise perception of fine geometric details.

We propose a technique that allows an unprecedented level of dexterity in electrical muscle stimulation (EMS), i.e., it allows interactive EMS-based devices to flex the user's fingers independently of each other. EMS is a promising technique for force feedback because of its small form factor when compared to mechanical actuators. However, the current EMS approach to flexing the user's fingers (i.e., attaching electrodes to the base of the forearm, where finger muscles anchor) is limited by its inability to flex a target finger's metacarpophalangeal (MCP) joint independently of the other fingers. In other words, current EMS devices cannot flex one finger alone, they always induce unwanted actuation to adjacent fingers. To tackle the lack of dexterity, we propose and validate a new electrode layout that places the electrodes on the back of the hand, where they stimulate the interossei/lumbricals muscles in the palm, which have never received attention with regards to EMS. In our user study, we found that our technique offers four key benefits when compared to existing EMS electrode layouts: our technique (1) flexes all four fingers around the MCP joint more independently; (2) has less unwanted flexion of other joints (such as the proximal interphalangeal joint); (3) is more robust to wrist rotations; and (4) reduces calibration time. Therefore, our EMS technique enables applications for interactive EMS systems that require a level of flexion dexterity not available until now. We demonstrate the improved dexterity with four example applications: three musical instrumental tutorials (piano, drum, and guitar) and a VR application that renders force feedback in individual fingers while manipulating a yo-yo.

Vibrotactile and friction texture displays are good options for artificially presenting the roughness and frictional properties of textures, respectively. These two types of displays are compatible with touch panels and exhibit complementary characteristics. We combine vibrotactile and electrostatic friction texture displays to improve the quality of virtual textures, considering that actual textured surfaces are composed of both properties. We investigate their composition ratios when displaying roughness textures. Grating roughness scales with one of the six surface wavelengths are generated under 11 display conditions, and in 9 of which, vibrotactile and friction stimuli are combined with different composition ratios. A forced-choice experiment regarding subjective realism indicates that a vibrotactile stimulus with a slight variable-friction stimulus is effective for presenting quality textures for surface wavelengths greater than or equal to 1.0mm.

Background Our previous studies have shown that electrical stimulation from the skin surface to the tendon region (Tendon Electrical Stimulation: TES) can elicit a force sensation, and adjusting the current parameters can control the amount of the sensation. TES is thought to present a proprioceptive force sensation by stimulating receptors or sensory nerves responsible for recognizing the magnitude of the muscle contraction existing inside the tendon, so it can be a proprioceptive module of a small-size, low-cost force feedback device. But there is also suspect that TES presents only strong, noisy skin sensation. From previous study, it was found that TES has some limitation on varying sensations. Methods In this study, in addition to characterizing the proprioceptive sensation induced by TES, we constructed a multimodal presentation system reproducing a situation in which force is applied to the hand was offered, so as to investigate whether TES contributed to the reproduction of haptics cooperating with other modalities, rather than disturbing them. Specifically, we used vibration to present a cutaneous sensation and a visual head mounted display (HMD) system to present simultaneous images. Using this system, we also evaluated the efficacy of TES itself and that of the multimodal system involving TES. Results We found that TES, along with visual and vibration stimulation, contributed to the perception of a certain force. Conclusions Thus, TES appears to be an effective component of multimodal force sense presentation systems.

Humans can perceive tactile sensation through multimodal stimuli. To demonstrate realistic pseudo tactile sensation for the users, a tactile display is needed that can provide multiple tactile stimuli. In this paper, we have explicated a novel printed tactile display that can provide both the electrical stimulus and the electrostatic force. The circuit patterns for each stimulus were fabricated by employing the technique of double-sided conductive ink printing. Requirements for the fabrication process were analyzed and the durability of the tactile display was evaluated. Users' perceptions of a single tactile stimulus and multiple tactile stimuli were also investigated. The obtained experimental results indicate that the proposed tactile display is capable of exhibiting realistic tactile sensation and can be incorporated by various applications such as tactile sensation printing of pictorial illustrations and paintings. Furthermore, the proposed hybrid tactile display can contribute to accelerated prototyping and development of new tactile devices.

In this research, we propose a system that can change the tactile material of the wall surface especially in the VR show house. In order to present multiple types of wall materials, an encounter type tactile sense presentation unit with a plurality of wall materials mounted on a uniaxial robot presents a specific type of wall material according to the movement of the hand of the experiencer. With this encounter type approach, users can experience tactile sensations of multiple kinds of realistic wall materials. We examined the specs necessary for such presentation, constructed the system, and conducted a user study to examine the effect of the proposed system, comparing with visual only and visual + force only conditions.

The Hanger Reflex is a phenomenon in which the head rotates unintentionally when it is sandwiched by a wire hanger. The reflex is effectively generated by pressing on specific points, and can be reproduced by pressing with an actuator. We propose the HangerOVER, an HMD-embedded haptic display that can provide both force and motion senses using the Hanger Reflex. In this paper, we designed a mechanism of controlling the Hanger Reflex using air balloons for HMD embedded haptic display, and confirmed the occurrence of the Hanger Reflex.

With the advantages of small size and light weight, electrical stimulation devices have been investigated for providing haptic feedback in relation to virtual objects. Electrical stimulation devices can directly activate sensory receptors to produce a reaction force or touch sensations. In the current study, we tested a new method of electrically inducing force sensation in the fingertip, presenting haptic feedback designed to alter perceptions of softness, hardness and stickiness. We developed a 3D virtual reality system combined with finger-motion capture and electrical stimulation devices. We conducted two experiments to evaluate our electrical stimulation method and analyzed the effects of electrical stimulation on perception. The first experiment confirmed that participants could distinguish between the directions of the illusory force sensation, reporting whether the stimulation flexed their index finger forward or extended it backward. The second experiment examined the effects of the electric current itself on the intensity of their perception of the softness, hardness and stickiness of a virtual object.

With the advantages of small size and light weight, electrical stimulation devices have been investigated for providing haptic feedback in relation to virtual objects. Electrical stimulation devices can directly activate sensory receptors to produce reaction force or touch sensations. In the current study, we tested a new method for inducing electrical force sensation in the fingertip, presenting haptic feedback designed to alter softness, hardness and stickiness perception. We developed a 3D virtual reality system combined with finger-motion capture and electrical stimulation devices. The system can provide visual feedback and the sensation of illusory force that moved the index finger by forward-flexion or backward-extension using tendon or cathodic stimulation. In the demo, participants can experience the sensation of softness, hardness and stickiness of a virtual object.

A method to present force sensation based on electrical stimulation to the tendon has been suggested, and the occurrence of the sensation was considered due to the contribution of proprioceptors such as Golgi tendon organs. However, there was no clear evidence about the contributing receptors and because the method uses percutaneous electrical stimulation, there are other candidates, the cutaneous receptors. In this paper, we conducted experiments to determine whether the force sensation generated by this method is due to cutaneous sensation or proprioception, by changing the effective depth of electrical stimulation with electrodes spacing. As a result, it was shown that when the electrical stimulation could reach to deep tissue receptors, the force sensation was felt clearer, suggesting possible contribution of the proprioceptor.

This study demonstrates that the simultaneous use of two types of representative principles for tactile texture displays, vibrotactile and electrostatic friction stimulation surpasses either type of stimulation. We used a set of sinusoidal grating scales with different surface spatial periods as simulated textured surfaces for testing the quality of texture displays. Experimental participants judged the best stimulus condition among the vibrotactile, electrostatic friction, and the conjunctive stimuli in terms of the reality perceived from the simulated texture stimuli. The use of vibrotactile and electrostatic stimuli in conjunction was judged to be the most realistic for the spatial periods of 1 and 2 mm, whereas noticeable differences among the three stimuli conditions were not reported for small spatial periods of 0.2 and 0.5 mm. The simultaneous use is effective for simulating the surfaces with middle-level asperity.

We developed “Finger Glove for Augmented Reality” (FinGAR), which combines electrical and mechanical stimulation to selectively stimulate skin sensory mechanoreceptors and provide tactile feedback of virtual objects. A DC motor provides high-frequency vibration and shear deformation to the whole finger, and an array of electrodes provide pressure and low-frequency vibration with high spatial resolution. FinGAR devices are attached to the thumb, index finger and middle finger. It is lightweight, simple in mechanism, easy to wear, and does not disturb the natural movements of the hand. All of these attributes are necessary for a general-purpose virtual reality system. User study was conducted to evaluate its ability to reproduce sensations of four tactile dimensions: macro roughness, friction, fine roughness and hardness. Result indicated that skin deformation and cathodic stimulation affect macro roughness and hardness, whereas high-frequency vibration and anodic stimulation affect friction and fine roughness.

The most common method of presenting tactile stimuli to touch screens has been to directly attach a tactile display to the screens. This requires a transparent tactile display so that the view is not obstructed. In contrast, transparency is not required if the tactile stimuli are presented on the back of the device. However, stimulating the entire palm is not appropriate because touch screens are typically used by only one finger. To overcome these limitations, we propose a new method in which tactile feedback is delivered to a single finger on the back of a touch screen. We used an electro-tactile display because it is small and dense. The tactile display presents touch stimuli as mirror images of the shapes on the touch screen. By comparing cases in which the device was operated by one or two hands, we found that shape discrimination is possible using this method.

It is known that visual, auditory, and tactile modalities affect the experiences of eating and drinking. One such example is the “glug” sound and vibration from a Japanese sake bottle when pouring liquid. Our previous studies have modeled the wave of the vibration by summation of two decaying sinusoidal waves with different frequencies. In this paper, to enrich expression of various types of liquid, we included two new properties of liquid: the viscosity and the residual amount of liquid, both based on recorded data.

We developed a bed-style haptic display "Haptic Bed" that provides weight sensation to wide area of the user's body. This system comprises motors, belts, a cushion and a comforter to press and swing the user lying on the bed. Haptic Bed is a type of whole-body haptic interface, characterized by the presentation of low-frequency force with multiple degrees of freedom. The prototype system with two motors can present a weight sensation to approximately five regions of the abdomen. Although a sensation is only presented to the abdomen in this study, Haptic Bed can present a weight sensation to a wider area by increasing the number of motors. The system has the potential to enrich the audio visual experience in several ways, such as by expressing the sensation of a horrific ghost sitting on the user as part of entertainment content, or by presenting the existence of a remote relative as a telecommunication tool. Overall, the system changes a bed into a new medium through which immersive contents are presented in an immersive manner.

The hanger reflex is a strong force illusion that was previously known to occur in the human head. We applied the hanger reflex to the wrist and had expected that "sweet spots" would exist for the hanger reflex at the wrist, similar to the properties of the hanger reflex at the head. By measuring the pressure distribution and the rotation angle when the hanger reflex device was attached to the wrist, we found "sweet spots" that efficiently generate the hanger reflex at the wrist. Based on the pressure distribution obtained, we developed a device to control hanger reflex generation at the wrist. This device reproduces the pressure distribution by pressing on the hanger reflex "sweet spots" using four linear actuators, and thus generates the hanger reflex at the wrist. The results of user testing indicated that the device can produce rotational forces efficiently.

When a wire hanger is placed sideways on the head, and the temporal region is sandwiched by the hanger, the head rotates unexpectedly. This phenomenon has been named the “Hanger Reflex”. Although it is a simple method for producing pseudoforce sensation, the use of the wire hanger in this way has up until now been limited in posistion to the head. Here we report a new finding that when a wrist or waist is equipped with a device of a larger circumferance the arm or the body rotates involuntarily. This fact suggests that the Hanger Reflex principle might be applicable to parts of the body other than the head, leading to the possible compact whole-body force display. This paper documents the development and testing of the devices and, suggesting stable presentation of the rotational force.

We present a novel photo touch sensing architecture, HACHIStack. It can measure the approaching velocity of an object and predict its contact time with the touch screen using two optical sensing layers above the surface. The photo sensing layers form three unique capabilities: high-speed sampling, velocity acquisition, and contact time prediction. This work quantitatively examines these capabilities through two laboratory experiments, and confirms that the capabilities of HACHIStack are sufficient for multimodal interaction, in particular, touch-based interaction with haptic enhancement. We then present three applications with HACHIStack: 1) chromatic percussions (xylophone and glockenspiel) with haptic feedback; 2) no-delay haptic feedback with the sensation of tapping on various simulated materials (e.g., rubber, wood and aluminum); and 3) a virtual piano instrument that allows players to perform weak and strong strokes by changing the tapping velocity.

Kinesthetic illusion is a well-known phenomenon elicited by vibratory stimulation to muscle tendon, which presumably causes muscle spindle activity. It is a candidate for kinesthetic sense presentation by direct receptors stimulation, which may lead to novel compact or immobile haptic displays. However, kinesthetic illusion requires strong mechanical vibrations, which hinders its practical use. I proposed to use electrical stimulation to muscle tendon, in which Golgi tendon organ resides, to generate the illusion. The experimental results revealed that tendon electrical stimulation elicited a similar illusion of motion to the kinesthetic illusion.

Sensing the position and movement of the accelerator pedal in a vehicle is important for acceleration control and safety while driving. The accelerator pedal is controlled by the foot, but precise adjustment requires much training because the driver must rely on somatosensory cues, which provide limited feedback. In this study, we propose periodic tactile feedback for the accelerator pedal to provide an additional tactile cue. We conducted an experiment using a driving simulator to compare the lap time, the rate of off-track incidents and the subjective evaluation of controllability recorded in questionnaires. The experiment confirmed that the feedback makes the control of acceleration easier and facilitates safer driving.

With the aim of augmenting auditory sensation by tactile stimuli, we investigated cross-modal relationships between the two modalities, focusing on frequency. The results showed that frequency consonance between tactile and audio stimuli depends on the relationship between harmonics, in a manner similar to auditory waves, but with broader peaks.

Characters with body materials that are different from that of humans, such as metal robots or rubber people, frequently appear in movies and comics. While the abilities of their synthetic bodies can be easily observed from their actions, their somatic sensations are more difficult to appreciat e. Our aim in this work is to simulate the alteration of the material of the human body by means of vibrotactile feedback. The feedback represents the properties of the materials and is periodically applied to the elbow joint in synchrony with the elbow angle. This simulated sensation of having a different body material gives us the feeling of those characters. This technique can also be applied to improve maneuverability in the teleoperation of master-slave systems because it gives the operator a robot-like sensation.

Along public pathways, visual signs and audio cues are used by pedestrians to guide them into forming smoother pedestrian flows. However, often ignored or neglected, these signals require greater pedestrian attentiveness and appropriate conscious effort. To solve this problem, we have proposed the concept of "vection field". This is a field of optical flow that cues movement according to a pedestrian's motion. Visual stimulus within this optical flow leads pedestrians innately in specific directions without requiring direct interventions. We have implemented such a field by covering the ground with a lenticular lens screen; in this setup, neither power supply nor position tracking of pedestrians is necessary. An experimental result from our previous study shows that a vection field can direct pedestrians to one side. However, the quality of the optical flow such as image clarity and smoothness of motion was unsatisfactory in that it could cause a reduction in leading inducement. In this paper, we describe in detail a new display method involving a lenticular lens screen that yields an improvement in the quality of the vection field and ultimately pedestrian optical flow. Experiments showed improvements over previous attempts.

An electro-tactile display is a possible candidate for a tangible touch panel, because it only requires an electrode substrate that can be made transparent. However, although it needs relatively few components, it does still require several transistors per electrode, and wiring each electrode thus poses practical problems. This study therefore proposes the use of a repeated electrode structure to enlarge the display area of the electro-tactile display, without the need for additional electrical components. Skin impedance measurement, which was previously used for the stabilization of skin sensation, was utilized for sensing finger position, and the tactile pattern was presented only around the finger, enabling a larger presentation area.

We propose a tactile enhancement structure inspired by hair follicle receptors. Unlike other receptors, part of the hair follicle receptor is exposed to the outside. Recent research has shown that skin hair contributes to perception of minute forces that cannot be perceived with glabrous skin. We considered how the skin perceives these minute forces. Our tactile enhancement device mimics the structure of hair follicle receptors. A matrix structure simulating artificial body hair is driven by minute forces external to the skin surface. This structure can be used on any surface of the human body because it is fully composed of passive elements.

This paper proposes a simple 1 DOF rotational haptic display that achieves endless sharpening of a pencil. Many haptic applications have been proposed to present shapes, elasticity, viscosity, and other physical properties of the environment. While these are important to support many tasks such as teleoperation and computer aided design, we focus on the use of haptic display for amusement. We paid special attention to the feeling of ldquoaddictive comfortablenessrdquo induced by haptic stimulation. We take ldquopencil sharpenerrdquo as a typical example, because it is obviously comfortable and has addictiveness. Moreover, the mechanism is relatively simple because the sensation could be generated through 1 DOF haptic display. In this paper, we recorded force and sound of the real pencil sharpener and replayed the sharpening sensation through a haptic display.

When a head is equipped with a hanger made of wire sideways, and its temporal region is sandwiched by the hanger, the head rotates unexpectedly. We named the phenomenon ldquoHanger Reflexrdquo, and we have studied this phenomenon to understand its mechanism and to show the possibility of utilizing the phenomenon as a human interface. However, to use it as an interface, pain sensation induced by the hanger becomes a practical problem. In this paper, we determined the necessary conditions of the Hanger Reflex, and we developed an interface that can induce head rotation by using the Hanger Reflex, without giving pain to the user.

The goal of this study is to develop a haptic interface for dexterous manipulation. To achieve this, we proposed electrotactile-kinesthetic integration. Our electrotactile display presents natural touch sensations of objects. In addition, this display is so small that it is considered to not affect the moving range of fingers. The haptic interface for dexterous manipulation is realized by mounting it on a kinesthetic display having a wide workspace. The electrotactile display on the integrated haptic interface is used actively. Therefore, we actively evaluated the performances of the electrotactile display on the single-fingered prototype system. The results revealed the present performance of the system. Subsequently, it also shows the possibility of further improving of the haptic interface by devising an electrotactile rendering method.

The paper focuses on design and joint impedance control of a new teleoperated robot arm enabling torque measurement in each joint by means of incorporation of devised optical torque sensors. When the contact of arm with an object occurs, joint impedance algorithm provides active compliance of corresponding robot arm joint. Thus, the whole structure of the manipulator can safely interact with unstructured environment. In the paper, we describe detailed design procedure of the 4-DOF robot arm and optical torque sensors. To extract force signal from measured data, the gravity compensation algorithm was elaborated and verified. The experimental results of joint impedance control show that proposed strategy provides safe interaction of entire structure of robot arm with human beings and ensures the collision avoidance.

This paper introduces a pervasive sensor system for nursing homes, where daily activities of elderly persons are monitored by pervasive sensors all the time. Deterioration in the quality of nursing care for the elderly has become one of the biggest problems in the aging society and the authors have been challenging the problem by sensors embedded in a nursing room. The sensors accumulate position information of a subject person and his wheelchair, then it is utilized for prompt assists for the subject and also used for obtaining his life log. In our experiments, we obtained position data of an elderly person for a month and a half and analyzed his sleeping hours and the number of times of going to a restroom. This paper presents the concept of the system, overview of the current system and experimental results obtained

We have developed a new type of master hand to control a dexterous slave robot hand for telexistence. Our master hand has two features. One is a compact exoskeleton mechanism called “circuitous joint,” which covers wide workspace of an operator’s finger. Another is the encounter-type force feedback that enables unconstrained motion of the operator’s finger and natural contact sensation. In this paper, the mechanism and control method of our master hand are introduced and experimental master-slave finger control is conducted.

We previously proposed a new 3D form display actuated by shape memory alloy (SMA), which is capable of displaying large scale objects sequentially. Based on our devised method, our display uses a 16×16 array of pin-rods with 30mm stroke at 5mm intervals. In this paper, we discuss the control method of the shape memory alloy with a simple matrix drive circuit. This type of drive circuit can dramatically reduce the number of switch. In addition, we propose a novel approach using linear programming, where the simulated time to display a whole shape is reduced by about 50% or more with a large number of actuators.

We developed a robotic arm for a master-slave system to support "mutual telexistence," which realizes remote dexterous manipulation tasks and close physical communication with other people using gestures. In this paper, we describe the specifications of the experimental setup of the master-slave arm to demonstrate the feasibility of the mutual telexistence concept. We developed the master arm of a telexistence robot for interpersonal communication. The last degree of the 7-degree-of-freedom slave arm is resolved by placing a small orientation sensor on the operators arm. This master arm is made light and impedance control is applied in order to grant the operator as much freedom of movement as possible. For this development stage, we compared three control methods and confirmed that the impedance control method is the most appropriate to this system.

Humans can perceive not only the magnitude but also the direction of force applied on the fingertip. When we grasp an object, the weight of it is felt through force that is parallel to the skin of the fingertip, which is how the object can be grasped without slipping. Focusing on this point, we have developed a tactile sensor that can measure a distribution of force vectors. The measurement method is as follows. The tactile sensor consists of a transparent elastic body, blue and red markers inside the elastic body, and a color CCD camera. An applied force on the elastic body results in movements of the markers, which are acquired by the CCD camera. The distribution of force vectors is calculated using this information. This paper reports experimental evaluation results concerning accuracy of determining position of markers, determination of magnitude and direction of force, spatial resolution, and calculation timing.

We have proposed and developed a tactile display that uses electrical current as a stimulus. The main characterstic of this display is that each type of mechanoreceptor is stimulated separately so that "tactile primary colors" are defined. In this paper, we describe how we fabricated a 4/spl times/4 array electrode system to present surface roughness, patterns and relative motions.