Untethered Underwater Soft Robot with Thrust Vectoring

This paper introduces DRAGON: Deformable Robot for Agile Guided Observation and Navigation, a free-swimming deformable impeller-powered vectored underwater vehicle (VUV). A 3D-printed wave spring structure directs the water drawn through the center of the robot by an impeller, enabling it to move smoothly in different directions. The robot is designed to have a narrow cylindrical profile to lower drag and improve agility. It has a maximum recorded speed of 2.1 BL/s (body lengths per second) and a minimum cost of transport (COT) of 2.9. The robot has two degrees of freedom (DoFs) and is capable of performing a variety of maneuvers including a full circle with a radius of 0.23 m (1.4 BL) and a figure eight, which it completed in 4.98 s (72.3 °/s) and 10.74 s respectively. We operated the robot, untethered, in various environments to test the robustness of the design and analyze its motion and performance.