Could these robot sea turtles be used to save the real ones?

The first few days of life for sea turtles is often harrowing.

Hatchlings face a range of predators like crabs, birds and fish as well as eroding beach habitats under threat from climate change and environmental degradation. In fact, it is estimated that just one in more than 1,000 baby sea turtles make it to adulthood.

Yet researchers at the University of Notre Dame in the United States have developed robot turtles that they hope could one day be used to guide baby sea turtles to the ocean, boosting the endangered species’ chances of survival. Moreover, the creation of robots that can mimic the unique gait of turtles could advance other areas of robotics ranging from space exploration to search and rescue efforts, according to experts.

In the following question-and-answers, Yasemin Ozkan-Aydin, an assistant professor of electrical engineering at Notre Dame, provides insights into the project and explains why building robot turtles is a particularly interesting feat for roboticists.

“Sea turtle locomotion is unique because of its ability to adapt to different terrains (underwater, sand) while expending minimal energy. This versatility is due to the unique body shape, morphology of their flippers, and their varied gait patterns.

“Mimicking this adaptability requires an intricate understanding of how morphology, flexibility, and gait interact with the environments and how animals adapt their locomotion strategies accordingly. This knowledge is of great interest to robotic experts as they seek to enhance the performance, adaptability and robustness of their robots in locomotion.”

“Our sea turtle robot is not designed based on a single species but is an amalgamation of various sea turtle species. We studied the locomotion patterns of different species, including the loggerhead (Caretta caretta) and leatherback turtles (Dermochelys coriacea), and incorporated the most effective aspects into our model to maximize the adaptability and versatility of the robot. The robot's size and structure are modeled based on the dimensions of sea turtle hatchlings.

“The key parts of our robot are an oval-shaped body frame, four independently servo-actuated flippers, an Arduino-based onboard control unit, an IMU sensor, and a battery. The body frame and flipper connectors are 3D printed using Acrylonitrile Butadiene Styrene (ABS) material. The silicone flippers, designed to mimic the flexibility and stiffness of sea turtle flippers, are molded from DragonSkin 20 silicone materials.”

“Given our specific focus on sand-based locomotion, we encountered a notable challenge with the initial choice of actuators. These actuators did not perform well in the sand, often experiencing issues like sand becoming lodged in their gears and susceptibility to breakage.

“Additionally, the process of selecting the optimal material and shape for the flippers necessitated dedicated effort and exploration.”

“Robot sea turtles can be used in a broad range of sectors:

“Search and rescue operations: The robot's adaptability to diverse terrains makes it well-suited for search and rescue missions, particularly in challenging environments such as disaster-struck areas and coastal environments.

“Environmental monitoring: Equipped with the right sensors, these robots could be used for environmental data collection, helping monitor climate change, pollution levels and other environmental parameters.

“Infrastructure maintenance: The robot’s capability to navigate varied terrains could be applied to infrastructure inspection and maintenance tasks, such as pipeline inspections or power line surveillance.

“Space exploration: The locomotion principles learned from sea turtles could inform the design of extraterrestrial rovers, enhancing their ability to traverse rough and unpredictable planetary terrains.

“Education: This project also presents an engaging, hands-on tool for education, inspiring the next generation of scientists and engineers by showcasing the power of bio-inspired design.”

“Robotic sea turtles help us address several aspects of sea turtle behavior and conservation. Understanding how sea turtles adapt their locomotion to diverse environments can inform strategies for their protection. For example, it can guide the design of beachfront developments that accommodate sea turtle navigation and nesting habits.

“Furthermore, our turtle-like robots, driven by biological data and sharing the sea turtle's morphology, allow researchers to explore the impacts and benefits of specific turtle features without involving live animals. Another promising application is using these robots to safely guide sea turtle hatchlings from their nests to the ocean, minimizing the risks they face during this critical period.”

“Studying animals to inspire the design of robots is indeed a common practice in the field of robotics.

“There is a multidisciplinary research area called ‘Bioinspired Robotics’ in which researchers draw inspiration from nature's designs, mechanisms and functions to develop innovative robotic systems.”