Design and Testing of a Multi-Module, Tetherless, Soft Robotic Eel

This paper presents a free-swimming, tetherless, cable-driven modular soft robotic fish. The body comprises a series of 3D-printed wave spring structures that create a flexible biologically inspired shape that is capable of an anguilliform swimming gait. A three-module soft robotic fish was designed, fabricated, and evaluated. The motion of the robot was characterized and different combinations of actuation amplitude, frequency, and phase shift were determined experimentally to determine the optimal parameters that maximized speed and minimized the cost of transport (COT). The maximum speed recorded was 0.20 BL/s (body lengths per second) with a COT of 15.82. These results were compared against other robotic and biological fish. We operated the robot, untethered, in a variety of environments to test how it was able to function outside of laboratory settings.