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Built to bounce back

May 1, 2023

ASU robotics researcher and team design drone to cope with collisions

Search and rescue efforts following disasters like the massive earthquakes in Turkey and Syria are a race against time.

Emergency response teams need to quickly identify voids or spaces in building rubble where survivors might be trapped, and before natural gas leaks, water main flooding or shifting concrete slabs take their toll.

Advanced technology plays a vital role in these recovery operations. Thermal imaging equipment and sensitive listening devices are deployed to seek out signs of life. Small aerial drones could also survey otherwise inaccessible spaces, but the inherent fragility of current designs have limited their use. 

“We see drones used to assess damage from high in the sky, but they can’t really navigate through collapsed buildings,” said Wenlong Zhang, an associate professor and robotics expert in the Ira A. Fulton Schools of Engineering at Arizona State University. “Their rigid frames compromise resilience to collision, so bumping into posts, beams, pipes or cables in a wrecked structure is often catastrophic. They don’t recover; they crash.”

Zhang said aerial drones need to endure knocks and jolts to achieve their potential for search and rescue operations. Toward that end, he and his lab team have designed and tested a first-of-its-kind quadrotor drone with an inflatable frame. Uniquely, its stiffness is tunable or adjustable to absorb and recover from unexpected taps and thumps.

The results of their workOther authors of the new paper in Soft Robotics are Pham H. Nguyen, Karishma Patnaik, Shatadal Mishra and Panagiotis Polygerinos. were published on April 20 in the technology journal Soft Robotics

“We need to change our focus on avoiding environmental contact. Drones need to physically interact with their surroundings to accomplish a range of tasks,” Zhang said. “A soft body not only absorbs impact forces to provide collision resilience; it also offers the material compliance necessary for dynamic maneuvers such as perching.”

Perching is an example of controlled collision. Birds technically collide with tree branches or other structures as they land and perch. Their compliant joints and soft tissues absorb the impact force, and a passive locking mechanism in their feet enables them to grasp onto irregular surfaces without using muscular energy to hold them in place.

Zhang and his team drew inspiration from this avian model to design a hybrid fabric-based bistable grasper for their new aerial drone. Bistable means it has two unpowered resting states: open and closed. It simply reacts to the impact of landing by snapping closed and securely gripping onto objects of various shapes and sizes.

“It can perch on pretty much anything. Also, the bistable material means it doesn't need an actuator to provide power to hold its perch. It just closes and stays like that without consuming any energy,” Zhang said. “Then when needed, the gripper can be pneumatically retracted and the drone can just take off.”

This kind of contact-reactive, unpowered perching is important for sustained operations in the field. Drones can position themselves wherever required, and then turn off their rotors to conserve battery power.

Zhang said such dynamic environmental interaction can enhance the use of drones in search and rescue operations, but also for other purposes such as monitoring forest fires, aiding military reconnaissance and even exploring the surface of other planets.

“There are so many functionalities possible with conformable, reconfigurable soft aerial robots, so we hope our work here leads to even more novel, bio-inspired designs,” Zhang said.

Top photo: Arizona State University Associate Professor Wenlong Zhang and his team have developed a first-of-its kind quadrotor drone with both an inflatable frame to enable resilience to collisions and an innovative gripper than enables the device to securely perch on almost any surface. Photo credit: Arizona State University.

Gary Werner

Senior Media Relations Officer , Media Relations and Strategic Communications


'Chimp Empire': ASU professor studies community featured in Netflix series

Primatologist hopes documentary leads to conservation action

May 1, 2023

For more than 20 years, Arizona State University primatologist Kevin Langergraber has studied the Ngogo community of chimpanzees in Kibale National Park, Uganda.

The new Netflix series "Chimp Empire" was filmed about the Ngogo over a one-and-a-half-year period and directed by James Reed, who won the 2021 Best Documentary Feature for "My Octopus Teacher." The show is narrated by fellow Oscar winner Mahershala Ali.   A chimpanzee looking off into the distance surrounded by greenery. Miles is the largest chimpanzee ever seen in the Ngogo community. He held the alpha position for many years before he was deposed by his paternal brother, Jackson. Photo courtesy Kevin Langergraber

“I think the filmmakers have done an amazing job turning our scientific stories into compelling emotional drama that brings people in,” Langergraber said.

“'Chimp Empire' captures a year of many changes at Ngogo — one previously unified chimpanzee community, the largest ever known, split into two warring factions. And there were dramatic changes in leadership. The film ends contemplating the chimpanzees’ perspective on the events that happened. It speculates that Even Garbo (the oldest chimp at Ngogo) has not seen many years as eventful as this one.

"The filmmakers got incredibly lucky to film the events in the lives of the chimps that they did. It will take us years of scientific research to even attempt to understand the reasons for these events and the consequences they’ll have for the community in the future.”

Langergraber is an associate professor in the School of Human Evolution and Social Change and research scientist with the Institute of Human Origins.

Langergraber hopes the documentary will engage people’s interest in chimpanzees and spur efforts toward supporting their conservation.

“Films like these are important for getting people interested in chimpanzees. But in the end, awareness and appreciation of wildlife isn’t enough to conserve them … it has to result in action,” Langergraber said.

The Ngogo Chimpanzee Project, an nonprofit organization that supports conservation work with anti-poaching patrols and programs to reduce conflict between chimpanzees and humans over crop raiding, is hoping that the publicity generated by the film will result in more direct support. Learn more about the Ngogo Chimpanzee Project on Twitter, Instagram and Facebook.

This is the second documentary focused on this group of chimpanzees. The 2017 Animal Planet documentary "Rise of the Warrior Apes" was told through the view of the scientists who study the chimpanzees, including Langergaber.

Julie Russ

Assistant director, Institute of Human Origins