Transactions of the Virtual Reality Society of Japan
Online ISSN : 2423-9593
Print ISSN : 1344-011X
ISSN-L : 1344-011X
Volume 6 , Issue 1
Showing 1-14 articles out of 14 articles from the selected issue
  • Type: Cover
    2001 Volume 6 Issue 1 Pages Cover1-
    Published: March 31, 2001
    Released: February 01, 2017
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  • Type: Index
    2001 Volume 6 Issue 1 Pages Toc1-
    Published: March 31, 2001
    Released: February 01, 2017
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  • Type: Appendix
    2001 Volume 6 Issue 1 Pages App1-
    Published: March 31, 2001
    Released: February 01, 2017
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  • Takao Sato
    Type: Article
    2001 Volume 6 Issue 1 Pages 1-
    Published: March 31, 2001
    Released: February 01, 2017
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  • Juli Yamashita, Yukio Fukui, Osamu Morikawa, Shigeru Sato
    Type: Article
    2001 Volume 6 Issue 1 Pages 3-9
    Published: March 31, 2001
    Released: February 01, 2017
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    Haptic/force feedback device is an important three-dimensional haptic display whose application fields include computer aided design (CAD). For CAD applications, smooth interpolation of polygonized surfaces with "force shading" technique is very useful for maintaining high haptic-rendering refresh rates by reducing the cost associated with computing the exact collision point of the cursor and the object. The resolution requirement of such polygonization, defined by human sensory thresholds, is unknown. We have conducted experiments to measure the human absolute threshold values on smoothness of cylindrical surfaces approximated by tangent planes, which are interpolated in different ways. Two kinds of PHANToMs of different positional resolution (0.03mm and 0.07mm) were used as force feedback devices and cylindrical surfaces of radius 30 - 120 mm have been investigated. The results have shown that, (1) when reaction force direction is force-shaded, the absolute threshold is mainly defined by the maximum difference between the polygonal approximation and the true surface and stiffness, and (2) positional resolution of the equipment does not affect the threshold values significantly.
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  • Osamu Morikawa, Juli Yamashita, Yukio Fukui, Shigeru Sato
    Type: Article
    2001 Volume 6 Issue 1 Pages 11-17
    Published: March 31, 2001
    Released: February 01, 2017
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    In conventional video communications, gaze direction is not sent correctly and there is not proper eye contact usually. Most studies have tried to simulate it to real world. In this paper we propose a new approach of this problem. Creating the "ambiguously interpretative zone" of the gaze information, and presenting other information that helps to recognize whom the speaker looked at, listeners can select a correct gaze direction from the video image. Experimental result shows that the ambiguously interpretative zone can be created by controlling the video resolution.
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  • Takashi Shibata, Takashi Kawai, Akira Arimoto, Tetsuya Ohshima, Tomoe ...
    Type: Article
    2001 Volume 6 Issue 1 Pages 19-25
    Published: March 31, 2001
    Released: February 01, 2017
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    In this study, we developed the system of stereoscopic images for the purpose of the welfare application to the elderly. We carried out 2 experiments to evaluate the system. On experiment 1, we confirmed the stereoscopic vision of the elderly and examined the system and the image contents. On experiment 2, we mounted 3D display on the gait-training machine and examined the system and the image contents. From the result of 2 experiments, 3 points were suggested. 1) The subjects of this system were designated the activities of daily living (ADL) as a judgment. 2) There were both affirmative and negative opinion on the image presentation. 3) It was important to select the image contents.
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  • Chizuru NAKAGAWA, Mieko OHSUGA, Takashi TAKEDA
    Type: Article
    2001 Volume 6 Issue 1 Pages 27-35
    Published: March 31, 2001
    Released: February 01, 2017
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    We studied the response of autonomic nervous system in the "sickness" induced by visual and motion stimuli, to establish a guideline for designing systems free from the sickness. This paper reports the results of a basic experiment with four projected screens and a 6-DOF motion base. In addition to the characteristic autonomic responses in respiration and heart rate variability we have already identified, we found a new response in the present study, or very low frequency waves (0.05-0.2Hz) in the ECG baseline of a majority of subjects who have fallen into sickness.
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  • Takuro Kayahara, Tetsuro Ogi, Michitaka Hirose, Takao Sato
    Type: Article
    2001 Volume 6 Issue 1 Pages 37-41
    Published: March 31, 2001
    Released: February 01, 2017
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    The effect of moving visual stimuli on the perceived direction of moving sound was measured to investigate whether the visual motion induces motion sensation of static sound. The dynamic interaural time difference (ITD) was used as the cue for sound motion, and the effect of two types of moving visual stimuli (single point-light and random-dot patterm) on the dynamic ITD was examined. As a result, the induced motion sensation of static sound whose magnitude was dependent on the type of visual stimuli was obtained. With point light stimulus (1-deg disk), sound with static ITD moved to the same direction as that of moving visual stimulus. With 90-deg spreaded random-dot pattern, however, motion sensation of sound with static ITD was not obtained. These results suggest that the motion sensation of sound is calculated taking account of the information of visual motion and that the inference of causality between visual informantion and auditory information (1-deg disk was interpreted as a sound source, however, random-dot pattern was not) might underlie the calculation.
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  • Masayuki Kawai, Tsuneo Yoshikawa
    Type: Article
    2001 Volume 6 Issue 1 Pages 43-48
    Published: March 31, 2001
    Released: February 01, 2017
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    In this paper, we discuss haptic display for 1-DOF(Degree-Of-Freedom) grasping a virtual object by two fingers. Much research has been done on fundamental analysis for stability of haptic display. But it is difficult to apply the results immediately to grasping situations by two fingers, since the studies deal with a single device and a single object. This is because the fingertip force in grasping situations has two components, internal and external force. The conventional methods, which calculate the coupling impedance at each contact point separately, have no other alternative but to calculate the impedance mixing the components for internal and external force. So even if only the impedance for external force should be changed, the impedance for internal force is also changed at the same time. In this paper, we propose a new method, in which the coupling impedance is calculated separately for internal and external force. Second, we discuss the stability of the proposed method and compare with the conventional method. Then, we perform some experiments to confirm the effects of the proposed method.
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  • Kazuaki Goshi, Katsuya Matsunaga, Hiroki Nagata, Hayato Matsugashita, ...
    Type: Article
    2001 Volume 6 Issue 1 Pages 49-55
    Published: March 31, 2001
    Released: February 01, 2017
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    We developed a stereoscopic video system, which has high-resolution images for central vision and it is called the Q system. The Q system uses a compound image that is a wide-angle image with an embedded high-resolution image. However, the Q system could not be used under situations where many robots work at the same time. This is because it needs four channels of video signals and the available channels could be limited under such situations. Thus, we have developed a digital Q system. The system can be used under such restricted situations, because the required data transfer rate is adjustable by changing the compression rates for a high-resolution image and a wideangle image. In addition, the experiment confirmed that even though the systems used the same data transfer rate, the digital Q system could make teleoperation more efficient and more precise than a conventional stereoscopic video system and that even though the Q system only used the half data trasnfer rate of the conventional stereoscopic video system, it provide the same effiency and presision as that of the conventional stereoscopic video system.
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  • Satoshi Tadokoro, Rie Murata, Toshiyuki Matsushima, Yoshio Murao, Hide ...
    Type: Article
    2001 Volume 6 Issue 1 Pages 57-63
    Published: March 31, 2001
    Released: February 01, 2017
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    A motion base plays an important role in generating virtual sensation of the whole body motion such as on vehicles, horses, spacecrafts, and amusement machines. This paper proposes a new design of motion base using a parallel cable-driven mechanism. It has outstanding advantages over conventional Stewart platforms. Acceleration can last for a long period because possible distance of translation is long. Possible acceleration is larger in principle. Optimal mechanism design is performed for a class of WARP architecture having eight cables. Parameter optimization of mechanical design is performed for the motion range to maximize the acceleration duration. The prototype developed on the basis of the kinematic and dynamic analyses has the maximum motion range of translation ± 0.45m × ± 0.4m × 1.1m, and of rotation ±45° in roll angle, ±45° in pitch, and ±35° in yaw, showing acceleration 1G for 0.8 second without utilizing gravity.
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  • Type: Appendix
    2001 Volume 6 Issue 1 Pages 65-
    Published: March 31, 2001
    Released: February 01, 2017
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  • Type: Cover
    2001 Volume 6 Issue 1 Pages Cover2-
    Published: March 31, 2001
    Released: February 01, 2017
    JOURNALS FREE ACCESS
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