A method is proposed to control human grasping force unconsciously by generating small distributed vibration stimuli on a finger based on a human reflex action against detection of partial slippage of contact. Human beings can increase grasping force before the grasped object slips off the fingers based on afferent signals from tactile receptors that detect the expansion of the partial slippage area. We assumed that vibration stimuli that have an appropriate frequency and distribution generate a virtual sensation of partial slippages and induce a reflective grasping force increase. Grasping experiments with minute distributed vibration stimuli using ICPF (Ionic Conducting Polymer gel Film) actuators were performed. Experiments results showed that the effective vibratory frequency was 30 Hz, which is the most sensitive range for Meissner's corpuscles that are closely related to detection of partial slippage. We also found that distribution of vibration stimuli were important to produce human grasping force increase.

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The passive type force display is essentially safe, since it has no risk of overdrive. Because of its safety, many applications, such as training, clinical applications and amusement use are expected. However, to interact with or manipulate virtual objects, such as tracing over surfaces of the objects, unique control strategies are required. We had proposed a passive type force display system with ER (electro-rheological) brakes before. In this paper, we aimed to present smooth surface of virtual objects, developing some control algorithm to display a plane or a polygon. We also described comparison of their characteristics experimentally.

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This paper proposes an estimation method of elastic parameter using electromyogram and a prototype of "Haptic Broadcast" system for remote sharing of haptic sense. The elastic parameter of the object was estimated without disturbing the softness perception of the object by using electromyogram for pinch force estimation. The estimated elasticity was transferred over the computer network and displayed using fingertip softness display device, that consists of fingertip reaction force display units and fingertip contact area control modules. The remote-recognition experiment of eight kinds of elastic objects (0.008 to 0.7 N/mm^2) was performed in five volunteers. The experimental results showed that the remote haptic sharing is feasible with the proposed method.

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This paper proposes a distributed haptic museum, which is a distributed virtual museum with touchable exhibits, as an application using haptic media as well as audio and visual media. In the museum, we study an adaptive display control scheme of touchable exhibits in order to decrease the response time when displaying exhibits and to improve the output quality of haptic media as well as audio and visual media. The scheme carries out LoD (Level of Detail) control of exhibited objects and proactive transfer control of display files. We also study an adaptive streaming start control scheme of explanatory information. The scheme dynamically changes the start time of streaming of explanatory information according to network delay, delay jitter, and so on. We evaluate the output quality of media and demonstrate the effectiveness of the scheme by experiment.

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When a virtual object is grasped by human hand, the grasped and the slipped states should be both presented with reality. This paper presents a computational technique for calculating the static and dynamic friction force, in addition to friction moment applied to haptic rendering. The proposed technique is evaluated by using a five-fingered haptic interface named HIRO II combined with virtual reality simulation system.

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This paper describes the design of a novel force perception method for non-grounding force displays and the development of a handheld force display based on the method. The force perception method is attributed to the nonlinear characteristics of human tactual perception; humans feel rapid acceleration more strongly than slow acceleration. The method uses periodic prismatic motion to create asymmetric acceleration leading to a virtual force vector. A prototype of the handheld force display that generates one-directional force using a relatively simple mechanism was built, and its performance was tested in terms of both physical and perceptual characteristics. We verify the feasibility of the proposed method through experiments that determine the display's motor's rotational frequency that maximizes the perception of the virtual force vector. In addition, we examine the effect of the frequency of acceleration change and the amplitude of force on implicit, functional judgment of the perception of the virtual force vector.

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Vibrotactile displays are expected to be effective tools for presenting personal information. When designing a vibrotactile information display, it is important to present correct, stable stimulation. However, the mechanical stability of the vibration is affected by many conditions such as how the vibrators are attached to the person, where they are attached, as well as other factors. In order to maintain the target frequency and amplitude of the vibration independent of the affective factors, we propose a feedback method for vibrotactile displays. Then, we did a subjective experiment by using this feedback system. We found that the feedback gave some change to the sensation of most of the subjects.

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In vision, after prolonged seeing of motion in one direction, illusory motion in the opposite direction is observed in physical static visual patterns (known as "waterfall illusion"). This phenomenon is referred to as Motion After Effect (MAE). MAE has been useful to study, without brain imaging, information processing in visual perception. Although some tactual illusions have been observed, obvious tactual MAE has not been reported. We, however, found clear and robust MAE in tactile sensation by using physical motion stimuli for test probe. We suppose that this research will make a contribution to investigate mechanism of tactual motion perception.

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We propose a new tactile display using acoustic radiation pressure. The display produces localaized force within a 1 mm diameter focal point and 2 gf total force. The fructuation of the gain was within 4 dB in the range of 20-1000 Hz. By steering the focal point using a linear phased array, the display creates various precise spatio-temporal patterns of pressure distribution on the skin. We conducted psychophisical experiments on tactile apparent movement and confirmed that tactile apparent movement can be observed even if non-vibratory simului are used.

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Our previous study resulted in the development of a non-grounding torque-displaying interface, "GyroCube". The GyroCube is an interface without earth-grounding base or reaction base on the human body which represents rotational force sensation in an arbitrary constant direction continuously by adjusting rotation velocities of three motors in x-, y- and z-coordinate axes, on the basis of the non-linear human sensory characteristics. In this study, a force and torque hybrid interface, "GyroCubeSensuous" has been developed which provides the sense of forward movement out of reciprocated vibration of micro-displacement through adroit utilization of human sensory characteristics. This makes you experience an illusion in the haptic sensation, such as getting heavier or lighter, and even lifting in a constant direction continuously.

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When human beings touch an object in a space, they actively move their fingers. They can perceive the shape of the object, even which is larger than the fingertip due to the active touch movement. In current paper, we propose a new technique for displaying tactile shape using the active touch movement. If the object is moved in the same or opposite direction during the finger movement, the width of the object is perceived as expanded or shrunk. Controlling the velocity of the object, indicated width can be displayed. Therefore, we investigate the relationship between velocity and perceived width of the object.

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In order to understand the method of controlling the intensities and the areas of pressure sensations evoked by the electrical stimulation of a sensory nerve fiber, the quantitative relationship was studied between the stimulation signal (which is input intraneurally into a single slowly adapting mechanoreceptor unit (type I) using micro electrical stimulation method) and the subjective intensities and the areas of the evoked sensations. The subjective magnitude of the evoked sensation was found to intensify with an increase in the stimulus frequency.

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When the hand is stimulated during hand movements, humans can localize the stimulated position even without visual guidance. This is because the sensorimotor system integrates internal information of the hand's location and perceived temporal information of the stimulus. It is reported that when transient tactile stimulation was presented before, during or after hand movements, the stimulus was systematically mislocalized. The mislocalization was interpreted as a result of mismatch between internal information and the physical location of the hand. However, typical environments exhibit a high degree of spatiotemporal coherence, and a different spatial localization strategy may be more adaptive to the continuous case. Here, we examine the time courses of localization for both transient and intransient vibration stimuli, to gain further insight into the spatial localization mechanism of the hand.

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In this paper, we describe a new design of haptic texture display consisting of fifty vibratory pins that evoke a virtual touch sensation of textured surfaces contacted to the user's fingerpad. A pin drive mechanism was fabricated by adjusting a natural frequency to efficiently expand the displacement of a piezoelectric actuator. An improved control system enabled fine amplitude changes in 200 steps. Sensation intensity was scaled and indicated by a power function of pin amplitude. We measured, as fundamental evaluation, the difference threshold of object's spatial frequency presented on the display with four different intensity waveforms. Moreover, matching tests between real and virtual textures were performed to evaluate the quality of presentation.

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This paper describes development of a small and high-resolution surface type haptic display. This device consists of 64 (8×8) linear actuators that are set with no space between them. Each linear actuator consists of a lead screw, a DC servomotor, and a force sensor. It has ability to present arbitrary force and shape by changing its length interactively. The size of its base is 4mm (width) × 4mm (depth), therefore, the device is practicable to present high resolution force rendering. Some rigidity distribution rendering algorithms were evaluated through experiments.

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In our previous studies, we have proposed a novel tactile stimulation method named "Suction Pressure Stimulation (SPS)." The method is based on our finding that humans can not discriminate suction from compression when the skin is pulled through a hole with a negative air pressure. This illusion indicates that tactile mechanoreceptors detect not stress nor strain tensor directly but scalar parameters such as strain energy density. In this paper, we clarify optimal conditions for achieving the illusion. Comparing the results of psychophysical experiments with simulation analyses of the SPS, we discuss physical parameters sensed by tactile receptors.

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This paper focuses on platforms for computer-human interaction and communication, with intuitive interfaces. The authors propose and examine "i-ball 2 (interactive/information ball 2)", which consists of a crystal-ball-like display and several types of input interfaces. i-ball 2's display system is unique. By using lens, the image appears as if it were in the ball. And i-ball 2 has two display systems and up to two users participate in interactive experience. Input interfaces of i-ball 2 are ball rotation, camera input and optical switches. The authors implemented 1) 3-D display, 2) amusement-oriented, 3) communication-oriented based on facial expression, and 4) simplified mutual telexistence (videoconference) applications. The authors exhibited i-ball 2 and believed that it is effective for intuitive computer-human interaction through the users' reaction.

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We propose a method of generating tree models which enables users to generate, manipulate and edit the shape of tree models based on growth simulation by using direct three-dimensional (3D) input. For this purpose, three-dimensional (3D) spatial information is introduced to the well-known L-system as an attribute of the growth simulation. Moreover, we propose an efficient data structure of L-strings in order to speed up the generating process of tree models.

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In this paper, we discuss an ad-hoc optical network for Real World Computing. This system provides the user for hi-speed data transfer ability in real world. Intuitive light-axes selectivity provides the hi-speed data transfer ability and communication ability under distant position at a same time. Characteristic layout, placing photo-diode directed to image sensor, and receiving reflected light signal from it is realize those features. In this paper, we introduce the system including user's eye as a image sensor, and enable to control light-axes using user's view field.

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In the field of genome science, researchers analyze gene expression data to clarify gene functions and to find suitable genes for drug development. In the analysis, they cluster genes using gene expression profiles and interpret them biologically using known information. However there are challenges with this approach. They often utilize trial and error method to set the parameters for clustering or extracting genes. At the same time, they have to get related genome information from web sites, thus it is difficult for them to do these tasks concurrently. They have to remember the analysis process and the parameters. In order to address this problem, this paper proposes a visualization method for gene expression analysis. Data from several web sites are integrated into one virtual environment in order to present them as if they were many papers on a desktop. Analysis process and history are displayed to help to remember analysis process. Parameters are also displayed in order to grasp the whole parameters at a glance. This system is implemented in an immersive projection display, CABIN. Based on our evaluation, we observed that by using proposed visualization method, it is easy for genome researchers to understand the analysis process, and they are able to perform the analysis that was not feasible previously.

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Young children often build various structures with wooden blocks; structures that are often used for pretend play. Based on this traditional toy, we propose a novel interactive toy for children, maintaining the physical assets of wooden blocks and enhancing them with automation. We name our interactive toy system "TSU.MI.KI." "TSU.MI.KI" consists of a set of computerized blocks equipped with several input/output devices. Children can tangibly interact with a virtual scenario by manipulating and constructing structures from the physical blocks, and by using input and output devices that are integrated into the blocks. We implemented an application with this system and evaluated by observating actual childrens' play with this application.

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High performance of PC, computer graphics and virtual reality technology have enabled us to develop medical systems for surgery trainings. These systems require so fast calculation algorithms for real-time simulation that there should be some constraints for simulation models such as limitation of deformed area, pre-calculation of inverse matrices and reduction of control points. In some applications, however, deformed area cannot be limited and inverse matrices cannot be pre-calculated. Also, reduction of control points causes no inverse matrices due to zero determinants of stiffness matrices. Therefore, we propose a stabilization method of deformation for a neurosurgery simulator, which deforms blood vessels. This method requires the least control points and also always has non-zero determinants of stiffness matrices so that blood vessels can be stably deformed in real-time.

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