Abstract
In this lecture, we discuss characteristics of cm-scale dynamics, i.e., insect world dynamics, which is not strongly affected by gravity and introduce mobile robots with abilities based on such scale effect. While a volume force such as gravity and a surface force such as air resistance and friction are proportional to the length cubed and the length squared, respectively, a muscle force is proportional to the section area. Therefore, tiny insects decrease own weight exponentially and increase the surface force and muscle force relatively. This is why they fly without difficulty, accelerate largely, turn sharply, and cling on a vertical wall easily. The butterfly-style flapping robot with the wing span of 10cm and the weight of 0.5g which was developed based on this design principle, i.e., scale effect, realized flapping frequency of 10Hz and take off of 10G. Moreover, the legged robot with the body length of 5.5cm and the weight of 9g ran at velocity of 11 body-length/s on the ground and 5 body-length/s on the water and the claw-type robot with the body length of 8cm and the weight of 13g climbed up and down a vertical wall.
