Development of a new jellyfish-type underwater microrobot

Biomimetic microrobots, with multiple degrees of freedom, that can walk and swim smoothly in water are important topics in the field of underwater monitoring for applications such as pollution detection and video mapping. We propose a new type of underwater microrobot using eight ionic polymer metal composite (IPMC) actuators as legs to resolve the problems of asymmetry in previous crawling microrobots. We developed a prototype of this underwater microrobot and conducted experiments to evaluate its walking, rotating, and floating speeds. This microrobot had better performance in walking and rotating than the previous model. Although it achieved its flotation by electrolysing water around the IPMC surface, the electrolysis process was not easy to control. To improve the floating motion, we propose a new jellyfish-type microrobot that moves like a jellyfish when floating and sinking and has four IPMC actuators aslegs in place of the jellyfish's antennae. We conducted experimentsto analyse the floating motion for three types of bodies and calculated the theoretical floating speeds. We developed a prototype of this jellyfish-type microrobot and evaluated the floating and walking speeds experimentally.