This paper deals with inter-destination (or group) synchronization control for haptic media in the case where two groups each of which consists of two players play a networked real-time game in which the two players in each group do collaborative work. The synchronization maestro scheme, which the authors previously proposed, is enhanced and applied to the control. We investigate the influences of how to determine the reference output timing on the fairness and the efficiency of the work. By experiment, we also demonstrate the effectiveness of a proposed method which employs two different reference output timings. The method adjusts the earlier output timing in a group to that in the other group and also adjusts the remaining two output timings.

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We propose a wearable haptic display to present the sensation of weight and inertial force of virtual objects, which is based on our novel insight that the deformation on fingerpads makes a reliable sensation of weight even when the proprioceptive sensations on wrist and arm are absent. The goal of this project is to meet the increasing demand for realistic haptic feedback with a simple haptic display that delivers realistic existence of virtual objects in entertainment, augmented reality or telexistence systems.

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When we recognize objects, multiple sensory information (e.g., visual, auditory, and haptic) is used with fusion. For example, both eyes and hands provide relevant information about an object's shape. We investigate how sensory stimuli interact with each other. For that purpose, we developed a system that gives haptic/visual sensory fusion using a mixed reality technique. Our experiments which focus on the sense of sharpness along with egde regions show that the haptic stimulus seems to be affected by visual stimulus when a discrepancy exists between vision and haptic stimuli.

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Measuring the force feedback from the object, describing it in virtual space, and displaying it in real time are necessary for the purpose of displaying the three-dimensional (3D) force feedback from a real object. We have constructed a system realizing these procedures. In the system, 3D force feedback from an object is described by interpolating measured data using Radial Basis Function (RBF). Real-time force display is carried out by direct access of a set of grid points sampled from the interpolated force field.

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An interactive tactile graphic display which acts by touch force has been developed as a trial. The trial model showed four usability problems through several usability experiments. Thus we re-designed three operation rules and developed a new image resampling algorithm to solve the problems. As the result, all problems shown in the previous system were solved. Furthermore a strategy of user interface design for interactive tactile graphic displays was shown through the development. In addition, an audio-tactile graphic system which can be used mainly to overcome tactile cognitive limitation was implemented as an application of the system.

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When a hand-held object accelerated in a pattern of high acceleration peak separated by low acceleration peak, the holder typically has the kinesthetic sensory illusion of being pushed or pulled continuously although the box has no connection to the ground. Using this effect in the gravity direction, we performed a heaviness perception experiment that involved comparing the weight of hand-held objects vibrating vertically with symmetric and asymmetric acceleration patterns. The results show that the perceived weight of an object vibrating with asymmetric acceleration increases compared to that of an object vibrating with symmetric acceleration when the high acceleration peak is generated in the gravity direction. On the other hand, a slight heaviness perception change was observed in the anti-gravity direction. We speculate that the nonlinearity between these results is caused by the perceptual broadening of pulse stimuli and the perceptual filling-in. The results also imply that the heaviness perception change increased with increases in the amplitude of vibration within the same frequency.

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Surgical training systems are needed for practices of surgical tasks. In such systems, shapes and deformations of soft objects must be fast calculated correctly to get realistic simulations. Generally triangles or tetrahedra, which are mesh elements, are used to represent virtual objects. However, when the number of mesh elements increase, the calculation time also increase. Moreover, we need much time if meshes are reassembled from the beginning, when we want to represent meshes according to deformations of virtual objects and interactions of virtual surgical tools. In this paper, we propose the algorithm for online remeshing of tetrahedral adaptive mesh. It allows fast dynamic structural modifications of tetrahedral adaptive mesh, according to stretch ration of edges of tetrahedra.

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Rehabilitation robots are effective to evaluate quantitatively rehabilitative therapies. Some kinds of haptic devices have been developed by many researchers and evaluated its efficiency with clinical tests for example upper limb training for patients with spasticity after stroke. Almost all the devices for upper limb rehabilitation have only 2-DOF for its active motion. But the upper limb of human works in 3-D space even except for the wrist; therefore designing a rehabilitation system for 3-D training is important. We developed new haptic devices which have 2-DOF force-feedback function on a worktable but the inclination of the worktable can be adjusted. We named this system "Quasi-3-DOF Rehabilitation System for Upper Limbs" or "PLEMO". Additionally, PLEMO is a passive haptic device using ER brakes with high safety. In this paper, we describe the mechanism of PLEMO and its software for the upper limb rehabilitation.

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We develop SmartTools as a part of the study of augmented reality. In this paper, we will introduce Micro Spidar. This design goal is Micro Spidar enables us to support micro operations within millimeter order. And we report about a trial implementation enables the modality transformation of optical leads into haptic sensations.

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This paper describes a decision method of placement of tactile elements for manual task recognition. Based on the mutual information of the manual tasks and tactile information, an effective placement of tactile elements on a sensing glove is determined. Although the effective placement consists of a small number of tactile elements, it has recognition performance as high as that of a lot of tactile elements. The effective placement of tactile elements decided by the method has been evaluated through experiments of recognizing the grasp types from grasp taxonomy defined by Kamakura.

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Tactile sensation usually provides reliable perception of an object's presence and its surface geometric profile. We can easily conduct a part of daily behaviors without looking at. However, the human tactile sensation is not necessarily faithful reproduction of the physical property of an object in real world. Here we report a novel tactile illusion named as "Fishbone Tactile illusion": in which depth perception of the contact surface occurs through stroking by a fingertip even though the surface profile is physically flat. We investigated the effects of the touching modes (static and active) and that of the surface profile of stimuli (presence/non presence and width of smooth-flat contact surface) on the illusionary perception of stimulus geometry. The results from the two experiments suggest that this illusion is induced when the stimulus satisfies following at least two conditions: 1. a central smooth region is surrounded by rough adjacent regions; 2. a central smooth strip is required when the width of its region is below 1.5 mm. This phenomenon may reveal the basic of human tactile system to process the perception of depth in finger tip because of its robustness and simplicity.

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Human can readily identify convex and concave geometry with his/her fingertip. Human characteristics of geometric perception have been studied in the field of Braille to optimize its readability. However, how accurate human can identify convex and concave geometry has not been studied very well. If such study would be performed, the result would give some insights on how the design parameters of a tactile display or sensor should be determined. Our experimental results revealed that signal detection performance and shape identification performance was almost the same for convex and concave geometry when the height (or depth) of the raised (or indented) area is over 0.2 mm. This method we used in the experiment can be applied in evaluating the performance of a developed robotic finger comparing with human shape identification performance in fingertip.

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We developed haptic display using propeller fan. It is constructed by DC motor with propeller, two step motor to control the direction and frame. In this research, we investigated the control method and some parameters using this haptic interface.

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We have developed a system named "Wide-view electronic working space" using a projection type wide-view stereoscopic image display. In this paper, we propose a system which displays and records both the 3D CG images that the user is looking at and the interaction between the CG and her/him at the same time from Objective Point of View. A camera can be set up in any place of the same coordinate system with the stereoscopic image display. Using the position and posture of the camera, the 3D CG images are drawn on the real world image from the camera. This system is extremely useful for a research tool in human interface (HI) field including 3D interaction, as well as for preparing images and videos for presentation of such a stereoscopic system.

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