Development of a biomimetic underwater microrobot for a father–son robot system

Conventional underwater intervention tasks are performed by underwater vehicles equipped with rigid multi-link arms. However, the movements of conventional mechanical arms exert reactive force on the vehicle platform due to their enormous bulk. Additionally, they cannot be used for small object recovery. In this paper, an ionic conducting polymer film (ICPF) actuator-based crayfish-inspired microrobot is designed and developed as a son robot for object recovery, which is connected to the amphibious father robot by copper wires. The crayfish-like son robot is used as the mechanical arm of the father–son robot system, which can grasp the small object especially in restricted spaces. The crayfish-inspired son robot actuated by ten ICPF actuators can realize underwater basic motions. The father robot can emit the son robot for object recovery. A proximity sensor is mounted in front of the microrobot between the two ICPF hands to implement the autonomous grasping motion. And we designed a blue LED-based underwater optical communication system to realize the communication between the father robot and the son robot for microrobot recovery. We carried out the experiments to confirm the basic operations of the microrobot, evaluate the performance of the communication system, and verify the blue LED tracking mechanism for microrobot recovery.