A Prototype of Underwater Microrobot System with An Artificial Swim Bladder

In this paper, we designed an underwater microrobot system. The system includes a microrobot and an artificial swim bladder. Underwater microrobots are useful in the seabed mining, biology and naval fields. They should have compact structure, easy to be manufactured, efficient locomotion, driven by low voltage, simple control system and upload ability. To attain these purposes, we designed a novel type of biomimetic locomotion with one-DOF legs. The locomotion includes two groups of ICPF (ionic conducting polymer film) actuators to realize the 2-DOF motions. The microrobot, named Walker-2, has 6 ICPF actuators and 3-DOF motion. It is 47 mm in diameter, 8 mm in height (in static state) and 0.61 g of dried weight. A fish inspired artificial swim bladder, named Bladder-1, is also developed. It is 32times14times14 mm³ in dimension and 0.33 g in weight. It is driven by one piece of ICPF actuator. It can float with a maximum upload of 0.17 g theoretically, while the experiment result shows the upload can be as weight as 0.26 g. The analysis and experimental result shows that the Walker-2 has some advantages, such as more flexible moving motion, stability, loads ability and so on. We also compared with some insect inspired microrobots and some microrobots with one-DOF legs, and the result shows a microrobot with this novel type of locomotion has some advantages. This structure has less actuator, less joints, simpler control system, and compact structure. The underwater microrobot system has powerful applications in the biomedical and naval fields