Tham khảo tài liệu 'electroactive polymers for robotic applications - kim & tadokoro (eds.) part 13', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 234 M. Konyo S. Tadokoro and K. Asaka Figure . Thresholds of tactile receptors for vibratory stimulus and selective stimulation ranges revised from Maeno 33 which was originally based on Talbot and Johnsson 34 and Freeman etal. 35 . Lower Limit Maximum Upper Limit Figure . Perceptual range of simple vibratory sensation For the IPMC tactile display selective stimulation is realized by changing drive frequencies utilizing the receptors response characteristics. It was confirmed by subject s introspection that the contents of sensation vary with the change of drive frequency as follows 1 Less than 5 Hz static pressure sensation SA I . 2 10 - 100 Hz periodical pressing or fluttering sensation as if the surface of a finger is wiped with some rough material FA I . 3 More than 100 Hz simple vibratory sensation FA II . Figure shows the experimental results of the perceptual range of simple vibratory sensations for a fixed-type display and b wearable display. It considered that the subjects begin to feel simple vibratory sensation when the Applications of Ionic Polymer-Metal Composites 235 information from FA II exceeds that from FA I. Figure shows that the detection threshold of FA II exceeds that of FA I in the vicinity of a frequency from 50 to 100 Hz. This agrees with the results of the perceptual range of vibratory sensation. To create integrated sensations a stimulating method using composite waves of several frequencies was proposed. Composite waves can stimulate the different kind of tactile receptors at the same time based on the selective stimulation method. In the earlier experiment using the fixed-type IPMC display 14 composite waves of high and low frequencies that present both pressure sensation and vibratory sensation at the same time were applied. The result clearly shows that over 80 of the ten subjects sensed some special tactile feeling which is clearly different from a simple vibratory sensation. The authors confirmed that the composite .
