A team of scientists at Carnegie Mellon University in the United States developed PATRICK, an autonomous underwater robot that artificially replicates the structure and behavior of ophiura, a species of brittle star similar to starfish.
The team’s goal was to create a flexible robot for simple underwater missions that would help scientists understand the behavior of brittle stars. To be as similar as possible to the animal, the scientists decided that the robot should not be connected to any external software, in order to allow the equipment to move more freely.
Thanks to feedback control, the robot chooses the direction it must take to achieve its goal on its own. According to EurekAlert, PATRICK has five legs fed by coils of SMA (shape-memory alloy), a type of metal with several advantageous properties, including high flexibility. When connected to electricity, the SMA metal heats up quickly and returns to its original shape.
“We use these shape-changing coils as a kind of ‘muscle’, causing the robot’s legs to bend in desired directions,” explained Zach Patterson, one of the researchers who participated in the study. The results are available on arXiv.
The robot is made of silicone, a material that makes it highly flexible and waterproof. “In order to control PATRICK’s motion, we developed several motion primitives: specific patterns of shape change coordinated among the limbs that move the robot as a whole,” explained the researcher to TechXplore.
This underwater autonomous soft robot can have numerous applications: it can be used in geological explorations, to obtain invasive ecological or biological samples, and help in the study of the locomotion mechanisms of brittle stars.