Micro Swimming Robots Based on Small Aquatic Creatures

摘要

The swimming behavior of small aquatic creatures was analyzed using the high speed video camera system. Based on the swimming analysis of the aquatic creatures, the micro swimming mechanism and micro diving robot propelled by alternating magnetic field were produced. The swimming characteristics of the micro mechanism and micro diving robot were developed. The swimming mechanism and diving robot swam successfully in the water. Frequency characteristics of the swimming mechanism and diving beetle robot were examined. The diving robot showed the higher swimming velocities at f0=4-12Hz. These experiments show the possibility of achievement of the micro robot driving by the wireless energy supply system. The results obtained are summarized as follows; (1) In the power stroke of the diving beetle swimming, hind legs are extended and driven backward to generate forward thrust. While in recovery stroke, hind legs are returned slowly to their initial position. (2) In forward swimming of the dragonfly nymph, only the fore pair and the middle pair of legs are active as a thrust generator. The orbits of fore- and middle-legs show almost the same, and draw the circle partially of the orbit. (3) The micro swimming mechanism composed of the NdFeB permanent magnet and film fin are driven by the alternating magnetic field. The swimming velocity of the micro mechanism depends on the frequency of alternating magnetic field at the constant voltage. (4) Flow visualization around the micro mechanism was created by the motion of powder and slow shutter speed photographic technique. The forward and backward surface flows and vortex flows around the micro mechanism were generated by the robot driving. (5) Visualization photographs of flow field around the tethered opossum shrimp show the generation of tow votices in right and left sides of the body. (6) The diving robot can dive into the water by sweeping the frequency of magnetic field. The diving robot can swim backward by the change of magnetic field frequency.