Scientists accomplish 'evolution on demand' by creating shape-shifting turtle robot

• Yale University researchers have developed a robot that can transform its limbs into flippers through an "adaptive morphogenesis" process when transitioning from land to sea.
• Known as ART (Amphibious Robot Turtle), the invention challenges the lack of adaptability favored by current robot design methods.
• The novel robot's ability to transition from land to sea, and vice versa, demonstrates that a single robot could collect data in challenging aquatic-terrestrial ecosystems like shorelines - reducing costs and energy.

Animal adaptation has long served as a source of inspiration for new technologies. For instance, we've seen krill-inspired adaptive buildings for regulating temperature and chameleon-like robots that can change color to blend into their surroundings. Better yet, trees and shellfish inspired the development of a material that could morph from soft to hard when exposed to light.

Now, researchers from Yale University have developed a robot that can transform its limbs into flippers through an "adaptive morphogenesis" process which it can use to transition from land to sea. Any ideas on which creature this could be inspired by (and, no, it's not a mermaid)?

This time, the inspiration comes from a turtle, or more correctly, 'turtles' (since the robot takes on traits from both land and aquatic types). And in case you hadn't known already, this group has a fossil record extending back more than 250 million years.

The innovative robot is Known as ART -- Amphibious Robotic Turtle. IE spoke with Robert Baines, the study's lead author, to learn more about how the development of ART came about and what we can expect for their future use in the real world.

The unchanging behaviors favored by current robot design methods prevent adaptability

We know that the current uses for mobile robots include everything from home cleaning to ecological monitoring, warehouse management, and research and repairs in hostile environments.

This expanding field of applications means that many new robots are designed to navigate a variety of situations and, therefore, environments. Yet, the static designs favored in current robot design methods prevent such systems from doing just that.

In their paper, the researchers highlighted that one strategy guilty of this is biomimetic design- which imitates an animal's morphology, propulsion system, and gait. They argue that this method lacks the advantages of engineered materials and mechanisms that can be used to outperform that of an animal.

Additionally, the study also mentioned how other methods of robotic design could result in energy-inefficient designs, due to the need to add a different propelling mechanism to the same robot body for each environment.

To address both issues, the team created ART.

Making robots with shape-changing components is an excellent way to enhance their adaptability

VIDEO: Yale researchers have created this Amphibious Robotic Turtle — aka ART — which has morphing limbs that can adapt shape, stiffness, and behavior when transitioning between land and water.

Learn more about ART and the research here: https://t.co/W5v6hmG2Fd @YaleSEAS #Yale pic.twitter.com/ncTNpoGB3u

— Yale University (@Yale) October 12, 2022

"We demonstrated how a robot can specialize for movement through multiple environments by augmenting the shape of its limbs and movement patterns," said Baines.

The scientist explained to IE that their results suggest that making robots with shape-changing components is an excellent way to enhance their adaptability. The development of ART also uses a reduced part count while at the same time expanding the number of tasks that robots can perform.

'A limb can switch between the streamlined shape of a flipper and the load-bearing shape of a leg'

The morphing robotic limbs are one of the key technologies in the Amphibious Robotic Turtle. Baines and colleagues fabricated these limbs with materials that enabled them to have radical shape and stiffness changes.

"A limb can switch between the streamlined shape of a flipper and the load-bearing shape of a leg," clarified Baines. "[This] switching between efficient terrestrial and aquatic shapes allows ART to specialize for movement through terrestrial and aquatic environments."

The amphibious robot essentially combines the characteristics of both aquatic and terrestrial turtles. Although they have shells and four limbs in common, these turtles have different limb forms and gaits that are tailored to their particular environments. Land turtles have rounder legs for carrying weight while walking, while sea turtles have extended flippers for swimming.

Sree Kalyan Patiballa, a first author on the study, explained to New Haven Register that the team used a type of plastic that becomes soft when heated to create the shape-changing limbs.

According to Patiballa, applying pressure and heat causes the limb to become flexible and alter its shape. After cooling and stiffening, it keeps the new shape.

The amphibious robot represents 'a form of evolution on demand'

ART can move on land using different four-legged terrestrial gaits when it is on 'legs'. However, when near a body of water, the legs can transform into flippers allowing the robot to swim efficiently with lift and drag-based aquatic gaits.

"You can almost think of [adaptive morphogenesis] as a form of evolution on demand," reported Karl Ziemelis, chief physical sciences editor for Nature.

'ART performs on par with, and in some cases outperforms, exclusively terrestrial or aquatic robots'

In contrast to earlier amphibious robots, this one uses form adaptation to employ the same components for propulsion in both water and land conditions. Other methods involve adding numerous propelling systems to a single robot, employing a different one for every environment, which might result in energy inefficiencies.

Additionally, Baines revealed to IE that the team "were excited to see that ART performs on par with, and in some cases, outperforms exclusively terrestrial or aquatic robots in terms of its movement efficiency."

Addressing the turtle in the room: What can you do with an amphibious robot that was inspired by land and sea turtles?

"For ART in particular, I think that environmental monitoring is a great potential application," disclosed Baines.

With the ability to adapt its shape to move efficiently through multiple environments, Baines envisages a single robot being able to collect data in challenging aquatic-terrestrial ecosystems like shorelines.

Diver support was another application mentioned. "For example, the robot could potentially transport parts or tools from land into the water to divers working on repairing a submerged structure," described Baines.

ART will be used to research robotic capability in the complex physics of the sea

The development of ART has spurred a great deal of interest and undoubtedly many intriguing questions. Baines confirmed that many of these center around "the interaction between a robot's shape, its behaviors, and its environment."

The researchers explained that they tested the amphibious robot at a canoe launch site at East Rock Park, New Haven, U.S. The biggest challenges were waterproofing the robot and helping ART navigate pebbles, sticks, sand, and waves found at the water-land boundary.

"We are especially interested in the transition between water and land because of its rich physics---the presence of waves, varied terrain, obstacles, and inclines," revealed Baines.

From a power cord-operated robot to a fully autonomous one

The Yale University team now hopes to produce a strategy for using ART as a platform to research robotic mobility and shape change amidst complex physical phenomena.

Baines also pointed out to NHR that ART is currently controlled by a human operator and is attached to a power cord. One of the next goals for the team is to create an autonomous robot whose limbs change in reaction to environmental changes.