Compliant Robotic Fish Research

Compared to watercraft propellers, fish are incredibly fast, agile and efficient. If humans could recreate it, we could revolutionize aquatic propulsion.  There’s already a body of research about fish swimming fluid dynamics. Even a quick YouTube search will give a taste of the variety of biomimetic robots trying to recreate it.  Most of these, you may notice, use a series of rigid links to approximate a fish’s body. For a year and a half starting in 2007, I worked on a robotic fish that instead has a flexible silicone tail using only a single servo. This was a solo undergraduate engineering research project under Prof. Charles Kim.

I joined the project when it was one year old, and just the tail had been designed. Things like how the fish would be sealed, how the components would rest inside the body, how to adjust buoyancy were handed off to me. I brainstormed, drew CAD, and made prototypes to determine plausibility. I finally made parts and created an effective fabrication process. In one semester, the fish went from just a tail to a self-contained, swimming robot. When I left the project, the fish was three times as fast, the tail was optimized, and there was a quantitative testing apparatus and process in place. Performance wise, it was as fast as the best of the robotic fish out there (but still a long way from tuna speed).