According to a recent study in Scientific Reports, Turing patterns can be used to develop a new method for designing and producing fabric-based soft pneumatic actuators (FSPAs).

Fabric-based soft pneumatic actuators (FSPAs) are flexible, soft devices that can deform or move when pressure is exerted on them. They function by inflating or deflating, which makes the fabric bend, stretch, or twist.

Soft robotics often relies on FSPAs because of their crucial flexibility and adaptability. Unlike traditional rigid robotic parts, FSPAs can interact safely with humans and delicate objects.

Thanks to their soft and lightweight nature, FSPAs are highly suitable for applications such as wearable devices, adaptive shelters, robotic grippers, and assistive devices. Their value lies in their low cost, safety, and flexibility.

However, designing and fabricating FSPAs is challenging. The challenge was addressed by the research team through the automation of the process.

The team consisted of Dr. Masato Tanaka and Dr. Tsuyoshi Nomura from Toyota Central R&D Labs., Inc. in Japan and Dr. Yuyang Song from Toyota Motor Engineering & Manufacturing North America, Inc. in the US.

Phys.org spoke to the researchers who shared their motivation for pursuing this research.

“The motivation behind this research stems from the recognized need in the soft robotics community for pneumatic actuators that can perform controlled movements using simple mechanisms without relying on specialized materials or technologies,” said Dr. Tanaka.

Turing patterns

“Our goal was to develop simple, low-cost FSPAs that achieve shape-morphing capabilities. We specifically focused on incorporating Alan Turing’s morphogenesis theory, known as Turing patterns, into the design process of these surface textures,” said Dr. Nomura.

Alan Turing put forth his theory of morphogenesis in 1952, describing how patterns in nature (stripes, spirals, etc) can arise from a uniformly distributed state.

“Inspired by Alan Turing’s work where the Turing pattern can be derived from isotropic reaction-diffusion equations, we employed a gradient-based orientation optimization method to design the surface membrane of FSPAs,” said Dr. Song.

Turing patterns result from systems that have reaction and diffusion components. The main idea is that we have two interacting substances, one of which promotes the promotion of both, and the second suppresses or inhibits the first one.

The result of this feedback loop is the formation of stable, repeating patterns, or Turing patterns, like the stripes seen on zebras and tigers.

Trial and error

The biggest challenge with designing FSPAs is the need for trial and error to find the right material.

“Traditional pneumatic structures typically use isotropic materials with specific geometric features, such as stitch lines, to achieve shape morphing,” explained Dr. Tanaka.

Soft isotropic materials, known for their uniform properties, are commonly used in traditional FSPAs. This guarantees that the material inflates or bends uniformly when pressure is applied.

However, designing and fabricating a material that deforms in a controlled and predictable way requires trial and error, and can be time-consuming. The research team’s objective was to bypass these limitations through process automation and optimization, resulting in more advanced and controlled movements in soft robotic applications.

“We employ a gradient-based orientation optimization method to design the surface membrane of these structures. This method assumes the use of anisotropic materials on membranes, where the orientation can vary freely, making the fabrication of such structures a significant challenge,” said Dr. Song.

“Our research addresses this challenge by utilizing Turing patterns to bridge the gap between material orientation-based optimization design and 3D printing,” added Dr. Nomura.

Automating the process

FSPAs consist of the material, which is the fabric used to construct the actuator and the actuator, which performs the movement in response to pressure.

The first step of their method was to optimize the orientation of the material—that is, how the fibers of the flexible fabric are arranged on the surface of the actuator.

For this, they used the nonlinear finite element method. Following optimization, the orientation layout was converted into particular patterns on the material.

These specific patterns were generated from a mathematical model of anisotropic reaction-diffusion systems used by the researchers. This pattern fills the entire surface and ensures that the material deforms in the desired way.

“By solving these equations and incorporating information about the distribution of optimized material anisotropy, we generated anisotropic Turing pattern textures corresponding to the original material anisotropy,” explained Dr. Tanaka.

To fabricate the FSPA, the researchers explored two methods: heat bonding and embroidery.

In heat bonding, a rigid fabric such as Dyneema is laser-cut into the required Turing pattern and then adhered to a softer fabric like TPU film using a heat press. In contrast, the embroidery technique embeds the Turing pattern into soft fabric with stiff thread, resulting in regions of different stiffness that allow for controlled movement.

“These fabrication methods demonstrated, offer scalable and cost-effective production possibilities for these advanced actuators,” explained Dr. Song.

Comparing with the classics

The research team compared their designs to classical simple designs, with their Turing pattern designs showing comparable and better performance.

For C-shaped designs, the Turing pattern proved more effective than classical designs, decreasing the distance between the actuator edges by roughly 10%.

For twisting movements, the Turing pattern designs performed similarly to classical designs. However, S-shaped bending is traditionally difficult to achieve.

“Our method can achieve any motion with a simple pneumatic input by designing the textural pattern printed on the membrane using our optimization approach,” said Dr. Nomura.

Future research could look into integrating Turing pattern designs with cutting-edge materials like shape memory or electroactive polymers, according to the research team, to develop actuators with improved dynamics.

The researchers also foresee exploring the scaling of fabrication techniques to accommodate mass production and larger actuators, possibly using approaches like 3D printing with flexible materials or automated weaving to enhance both efficiency and precision.

© 2024 Science X Network

By all accounts, Milagra the “miracle” California condor shouldn’t be alive today.

But now at nearly 17 months old, she is one of four of the giant endangered birds who will get to stretch their wings in the wild as part of a release this weekend near the Grand Canyon.

There is no more appropriate name for a young bird that has managed to survive against all odds. Her mother died from the worst outbreak of avian flu in U.S. history soon after she laid her egg and her father nearly succumbed to the same fate while struggling to incubate the egg alone.

Milagra, which means miracle in Spanish, was rescued from her nest and hatched in captivity thanks to the care of her foster condor parents.

The emergency operation was part of a program established some 40 years ago to help bring the birds back from the brink of extinction when their numbers had plummeted to fewer than two dozen.

The Peregrine Fund and the Bureau of Land Management are streaming the release of Milagra and the others online Saturday from Vermillion Cliffs National Monument, about 50 miles (80 kilometers) from the Grand Canyon’s North Rim.

Condors have been released there since 1996. But the annual practice was put on hold last year due to what is known as the “bird flu.” Highly Pathogenic Avian Influenza killed 21 condors in the Utah-Arizona flock.

“This year’s condor release will be especially impactful given the losses we experienced in 2023 from HPAI and lead poisoning,” said Tim Hauck, The Peregrine Fund’s California Condor program director.

Today, as many as 360 of the birds are estimated to be living in the wild, with some in the Baja of Mexico and most in California, where similar releases continue. More than 200 others live in captivity.

The largest land bird in North America with a wing-span of 9.5 feet (2.9 meters), condors have been protected in the U.S. as an endangered species since 1967. Many conservationists consider it a miracle any still exist at all.

Robert Bate, manager of the Vermillion Cliffs monument, said the release is being shared online in real time “so that the scope and reach of this incredible and successful collaborative recovery effort can continue to inspire people worldwide.”

California condors mate for life with a lifespan up to 60 years and can travel up to 200 miles (322 kilometers) a day, which they have been known to do as they move back and forth between the Grand Canyon and Zion national parks.

The Peregrine Fund started breeding condors in cooperation with federal wildlife managers in 1993. The first was released into the wild in 1995, and it would be another eight year before the first chick was hatched out of captivity.

The fund’s biologists typically don’t name the birds they help raise in captivity, identifying them instead with numbers to avoid giving them human characteristics out of respect for the species.

They made an exception in the case of #1221, aka Milagra. They saw her journey as emblematic of the captive breeding program coming full circle.

Milagra’s foster father, #27, was hatched in the wild in California in 1983. He was one of the first brought into the program as a nestling when fewer than two dozen were known to still exist worldwide.

Convinced it was the species’ only hope for survival, the U.S. Fish and Wildlife Service made an unprecedented, risky decision back then to capture the remaining 22 known to exist to launch the breeding program. Over time, it has grown with assistance from the Oregon Zoo, Los Angeles Zoo and San Diego Zoo Safari Park.

“Once they realized California condors were great parents in captivity, they started allowing them to raise their own species,” said Leah Esquivel, propagation manager at the fund’s World Center for Birds of Prey in Boise, Idaho.

Like all California condors in the wild today, Milagra’s biological parents were products of the program.

Milagra’s mother, #316, laid her softball-sized egg in a cave on the edge of an Arizona cliff in April 2023—one of her last acts before she succumbed to avian flu. Sick himself, her biological father, #680, did his best to tend to the egg, but prospects for survival dwindled. So, when he made a rare departure from the nest, biologists who had been monitoring sick condors swooped in and snatched the lone egg.

“(He) was so focused on incubating the egg that he was not leaving to find food and water for himself, risking his own life,” Peregrine Fund spokesperson Jessica Schlarbaum said.

They stashed the fragile egg in a field incubator and raced 300 miles (480 kilometers) back to Phoenix, not unlike a human transplant team carrying a heart in an ice chest.

To the amazement of all, the egg hatched.

Milagra tested negative for the avian flu and spent about a week at the Liberty Wildlife Rehabilitation Center in Mesa, Arizona, before she was taken to fund’s breeding facility in Idaho, where the foster parents took her under their wings.

Esquivel, the propagation manager, said Milagra’s foster mother, #59, has raised eight nestlings in her lifetime.

Esquivel described #59 as unique. While the bird never mates, she goes through all the other breeding motions each year and lays an egg.

“Her eggs are obviously infertile, but since she is a great mother, we use her and her mate to raise young,” Esquivel said. “We just swap the infertile egg out with a dummy egg, then place a hatching egg in the nest when we have one available for her.”

Milagra’s foster dad has sired about 30 young and helped raise nestlings in captivity for years.

After spending about seven months with foster parents, the youngsters head off to “condor school” in California to learn the basics: eating communally, strengthening muscles for flight and learning to get along with fellow condors.

For the biologists, recovery partners, volunteers and others who have persevered over the last year, Hauck summed up Saturday’s release of the birds from this year’s graduating class as “a moment of triumph.”

© 2024 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed without permission.