Development and experiments of a novel multifunctional underwater microrobot

Compact structure, multifunction, and flexibility are normally considered as incompatible characteristics for legged microrobots. Most robots focused on complex structure of multi-joint legs to attain the multifunction and flexibility, while others had poor flexibility for miniaturization. In the field of underwater monitoring for applications such as pollution detection and video mapping in limited space, underwater microrobots are urgently demanded. To realize these purposes, we have developed several types of microrobots with both compact structure and flexible locomotion. However, they just realized walking, rotating, swimming, or floating motions. Without biomimetic fingers, they could not do some simple operations, such as grasping and carrying any objects to desired place. So, in this paper, we designed a novel type of biomimetic locomotion employing ionic polymer metal composite (IPMC) actuator as one-DOF leg. Then we proposed a new type of underwater microrobot using ten ionic polymer metal composite (IPMC) actuators as legs or fingers, which could realize walking, rotating, floating, and grasping motions. Also, we developed a prototype of this underwater microrobot and carried out some experiments to evaluate its walking and floating speeds. In addition, we used six IPMC actuators as fingers to grasp some small objects and float up. To realize the closed-loop control for the microrobot, we used three proximity sensors to detect and avoid the obstacle while walking.