There are more than 35,000 species of fishes, and a key feature of this remarkable diversity is the variety of ways in which fish swim. For this year’s Charles and Marie Fish Lecture at the URI Bay Campus, Dr. George V. Lauder, a Harvard University biologist, will talk about his work with collaborators to develop several different self-propelled fish robots. These robotic models—from simple thin plastic panels to more complex tuna-like robots—can help scientists better understand fish locomotor dynamics and inform designs of a range of products, including underwater vehicles and body suits used by competitive swimmers.
We spoke with Dr. Lauder a week before his Friday, April 26 presentation and learned about the “Tunabot,” why shark skin is so amazing, and how we might move beyond the age of propeller-driven underwater vehicles.
What inspired you to study marine science, in particular fishes?
I grew up in the era of Jacques Cousteau and the first period of intense ocean exploration. I learned to scuba dive at a young age in the Mediterranean, and began observing fishes then. I always liked learning about how things work, so bringing that together with my love of the ocean world made studying fish biomechanics a natural for me!
You create fish robots to study how fish swim. Why not just work with the real thing?
I do work a lot with live fish to study their locomotion which is very rewarding as fish always do surprising things, but studying live animals has a number of limitations. Robotic systems provide nearly complete experimental control over movements and design. So it is easy, for example, to change the stiffness of the tail on a robotic fish to study the effect of stiffness on propulsion, but very difficult to ask a fish to change the stiffness of its tail on command!
What is it about shark skin that you find so captivating?
Shark skin is amazing—sharks are covered with many thousands of small scales or denticles, each like one of our teeth with an enamel-like outer coating, dentine, and a pulp cavity. These denticles have a complex shape that varies around the shark body, and different species of sharks vary greatly in their denticle structure. Skin denticles have some surprising effects on water flow over the body and we are studying how skin denticles might reduce the cost of swimming. I maintain a Twitter feed that is largely about shark skin and fish robotics if anyone is interested! (Editor’s note: And be sure to follow #SharkScaleSaturday on Twitter!)
The title of your upcoming Fish Lecture refers to underwater vehicles. How can a better understanding of fish locomotion inspire advances in underwater exploration?
Fish body shapes and propulsive systems have had over 400 million years of evolutionary time to fine tune their interaction with the surrounding water. There is a tremendous amount that we can learn from fish that can inspire underwater vehicle design, and begin to move us beyond the age of propeller-driven devices to systems with flexible bodies that move with the efficiencies and maneuverability of fish. Many fish species move with speed and agility through the water and in complex underwater habitats, and understanding how they do this can suggest engineering designs for more agile robotic systems for ocean exploration.
You’ve visited the Greenfins Aquaculture Facility here on the URI Bay Campus. How has that facility factored into your research?
Yes, I am very grateful that we were able to work at the Greenfins URI facility to obtain high-speed videos of tuna locomotion. These videos have helped us with the design and programming of a small robotic tuna—the Tunabot. I’ll present some information on the Tunabot in my talk, and discuss how we are trying to move the field of fish robotics into the performance space occupied by fishes such as tuna which exhibit high-speed locomotion.