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When we draw on paper with a pen or a stylus, we experience a sensation of drawing. The sensation is caused by a vibration generated by the interaction between the pen / the stylus tip and the microscopic irregularities on the paper. We can feel different sensations on different types of paper. When we rub a solid surface with such instruments, we can sense the texture of the surface through the instrument, as illustrated in Figure 1. In this study, we focus on this type of sensation and its recognition. If the drawing sensation can be reproduced at a remote site, we can consequently “feel” and “recognize” the texture. The sensation can improve an operation for a remote manipulation, or an experience of virtual reality. This paper deals with reproducing textures. This area of research has recently gained attention.
Figure 1. Texture recognition by drawing motion
Previously, some research groups had developed various methods of tactile/haptic displays. Various types of pin array tactile display were developed. Nakatani et al. developed 3-D shape display (Nakatani, Kajimoto, Sekiguchi, Kawakami, & Tachi, 2003). They used a coil-form Shape Memory Alloy (SMA) for the display. The display can present both visual and haptic feedback because the pin-rod array has a long stroke. Matsunaga et al. developed tactile display using SMA micro actuator (Matsunaga, Totsu, Esashi, & Haga, 2005). This method is an expansion of dynamic Braille display for blind people (Haga, Makishi, Iwami, Nakamura, & Esashi, 2005). Moving up and down by an SMA actuator, pin array configures some shape like simple graphics and alphabet. Changing surface shape contacted with operator’s finger physically, the device indicates tactile sensation. Changing pin height with some steps, the display can indicate not only 2-D shape but also 3-D shape. The pin array tactile display is forming real shape on the display. The resolution of the 2-D shape is determined by the diameter of the pin. On the other hand, the pin array is not suitable for fast movement.
Other research groups had developed various methods of stimulation for mechanoreceptors selectively. In human skin, there are four types of mechanoreceptors. N. Asamura developed a device to display tactile sensation by stimulating selectively mechanoreceptors in skin (Asamura, Yokoyama, & Shinoda, 1998; Makino, & Shinoda, 2005). The device has two type stimulations, an air pressure and an overall vibration. An air pressure stimulates shallow receptors, and an overall vibration stimulates both shallow and deep receptors. Kaijmoto et al. developed tactile feeling display using functional electrical stimulation (Kajimoto, Kawakami, Maeda, & Tachi, 1999). This method is a tactile presentation by electrical stimulation for mechanoreceptors selectively. Kaijmoto et al. developed Smart touch (Kajimoto, Inami, Kawakami, & Tachi, 2003; Kajimoto, Inami, Kawakami, & Tachi, 2004). The device can displayed visual image as tactile sensation. Konyo et al. developed a texture display using ICPF (Ionic Conducting Polymer gel Film) (Konyo, Akazawa, Tadokoro, & Takamori, 2003; Konyo, Yoshida, Tadokoro, & Saiwaki, 2005). The ICPF of the display stimulates mechanoreceptors selectively. The display could control roughness, pressure and friction sensations. Thus, the display could present texture feels by control such physical parameters.