Two-Handed Multi-finger String-Based Haptic Interface SPIDAR-8

Abstract

In this chapter, the authors propose a system for implementing direct, two-handed, multi-finger manipulations in a virtual world. To implement an easier-to-use means of direct, two-handed, multi-finger manipulations, it is necessary to give a sense of touch to the hands to make them feel like they are grasping an object and to make it easier for the user to understand the positional relationship between the user’s hands and the virtual object. Therefore, the authors constructed a system that provides force feedback to eight fingertips and that can display virtual hands (Walairacht et al. in Proceedings of the ninth international conference on artificial reality and tele-existence, pp. 233–236, 1999) making the same movements as the user’s actual hands in real time. Therefore, the authors constructed a system that provides force feedback to eight fingertips (called SPIDAR-8 Walairacht et al. in Proceedings of the IEEE international symposium on intelligent signal processing and communication systems, pp. 569–572, 1999 and Proceedings of the IEEE virtual reality 2000, p. 293, 2000). SPIDAR-8 is a device that can measure the positions of eight points and provide force feedback by using strings. Force feedback can be provided to a fingertip by attaching a cap-like apparatus to the ends of the strings and fitting this apparatus onto the fingertip. The virtual hands are displayed according to the eight fingertip positions calculated by SPIDAR-8. Then hand shapes are estimated from the positions of the eight points, and these hands are displayed together with the virtual object via computer graphics. Virtual hands making the same movements as the user’s actual hands are displayed in this way. With this kind of system, the user can integrate the haptic and visual information that is presented to efficiently perform direct, two-handed, multi-finger manipulations.