The Tunabot, a Robot that Learns From One of the Fastest Swimmers of the Seas

Replicating the movement of animals to develop human technologies is not always a successful strategy. For instance, many inventors in the Middle Ages learned it the hard way when they created flying devices that replicated the flapping of bird wings. A new generation of underwater drones based on biomimetics, however, is pushing engineers to reassess mobility and maneuvering capabilities. And that has driven them to learn from some of the sea’s creatures. The tuna fish, able to reach a top speed of up to 68 mph, is one of the strongest and fastest swimmers. And the source of inspiration for a technology prototype recently announced in the scientific journal Science Robotics.

This innovative technology project, codenamed Tunabot, has been carried out by using 3D printers. The test model, which is ten inches long, has a soft skin covering the rear and a hard casing for the front half. The internal engine that moves the tail works at a 15 Hz speed and endows the prototype with a similar speed to its natural counterpart, i.e., for times its body per second. The first version of the Tunabot includes a 10 Wh battery that allows it to cover up to 9 km. This would be an example of biomimetics, also called biomimicry, the discipline that looks for inspiration in nature to develop new technologies.

Biomimetic accuracy

The most striking thing, according to the research team from the cyber physics systems Link Lab at the University of Virginia, is how accurately the prototype’s movements mimic the real tuna fish. Not only in terms of kinematics but also regarding the relationship between the flapping frequency and the achieved speed. The tests of this biomimicry project have been carried out in a water tank, with the machine stabilized with a fishing line tether. A laser beam cuts across the plastic fish to measure the fluid motion shed by the robot with each sweep of its tail.

Currently, this new technology project does not have any practical applications. The goal is mainly to establish the foundations for the development of new machines to explore marine ecosystems and inspect infrastructures or offer recreational uses. Thus, more than building an underwater robot the first goal of the team was to understand the way fish move in the water, especially species like the tuna or mackerel. In another case of biomimetics, the previous underwater robot prototype developed by the team was based on the devilfish.

An in-depth study of biological swimming

In their press release, the researchers from the Mechanical and Aerospace Engineering department at the University of Virginia point out that they are looking into learning from biological swimming strategies to create more efficient underwater propulsion systems. And that is the most important difference with previous robotic fish, which offered little information on the biological data about the natural process. The specialists behind the Tunabot believe that the growing collaboration between biologists and experts in robotics will open many doors, both for science and engineering.  

Source: University of Virginia