'Bat Bot' Can Pull Off Impressive Aerial Acrobatics

The "Bat Bot" was designed to mimic how acrobatic bats are in real life.

Credit: Ramezani, Chung, Hutchinson, Sci. Robot. 2, eaal2505 (2017)

Whether they're swooping around to catch dinner or delicately hanging upside down to sleep, bats are known for their acrobatic prowess. Now, scientists have created a robot inspired by these flying creatures. Dubbed the "Bat Bot," it can fly, turn and swoop like its real-life counterpart in the animal kingdom.

Since at least the time of Leonardo da Vinci, scientists have sought to mimic the acrobatic way in which bats maneuver the sky. Someday, robotic bats could help deliver packages or inspect areas ranging from disaster zones to construction sites, the researchers said.

"Bat flight is the Holy Grail of aerial robotics," said study co-author Soon-Jo Chung, a robotics engineer at the California Institute of Technology and a research scientist at NASA's Jet Propulsion Laboratory, both in Pasadena. [The 6 Strangest Robots Ever Created]

Learning from animals

Bats may possess the most sophisticated wings in the animal kingdom, with more than 40 joints in their wings that enable unparalleled agility during flight, likely so that they can pursue equally nimble insect prey, the researchers said.

"Whenever I see bats make sharp turns or perch upside down with elegant wing movements, I get mesmerized," Chung told Live Science.

Previous work has developed a variety of flying robots biologically inspired by insects and birds. However, attempts to build robots that mimic bats have been met with limited success because of the complexities of bats' wings, such as their multitude of joints, the researchers said.

Now, Chung and his colleagues have developed the "Bat Bot," or B2, a robot that can fly, turn and swoop like a bat. The aim is "to build a safe, energy-efficient, soft-winged robot," Chung told Live Science.

The researchers said previous bat robots followed the skeletal anatomy of these flying creatures too closely, resulting in bots that were too bulky to fly. Instead, the scientists figured out which components were key to the beating of a bat's wing — the shoulder, elbow and wrist joints, and the side-to-side swish of their thighs — and used only those in their robot.

Whereas conventional flapping-wing robots used rigid wings, the Bat Bot has thin, elastic wings. "When a bat flaps its wings, it's like a rubber sheet — it fills up with air and deforms," said study co-author Seth Hutchinson, a robotics engineer at the University of Illinois at Urbana-Champaign. During the downward stroke, "the flexible wing fills up with air, and at the bottom of the downstroke, it flexes back into place and expels the air, which generates extra lift," he explained. "That gives us extra flight time."

Meet the Bat Bot

The Bat Bot's wings are made of bones of carbon fiber and ball-and-socket joints composed of 3D-printed plastic, all covered with a soft, durable, ultrathin, silicone-based skin only 56 microns thick. (For comparison, the average human hair is about 100 microns thick.)

The robot flapped its wings up to 10 times per second using micro-motors in its backbone. The Bat Bot weighed only about 3.3 ounces (93 grams) and had a wingspan of about 18.5 inches (47 centimeters) — measurements similar to those of Egyptian fruit bats, Chung said.

In experiments, the Bat Bot could fly at speeds averaging 18.37 feet per second (5.6 meters per second). It could also carry out sharp turns and straight dives, reaching speeds of 45.9 feet per second (14 m/s) while swooping down.

The researchers said their robot's softness and light weight make it safer for use around humans than, for example, the quadrotor drones that are popular commercially. For instance, the Bat Bot would cause little or no damage if it were to crash into humans or other obstacles in its environment, they said. In contrast, quadrotors spin their rotor blades at high speeds of up to 18,000 revolutions per minute, which could result in dangerous interactions, Chung said.

"The high-speed rotor blades of quadrotors and other craft are inherently unsafe for humans," Chung said. "Our Bat Bot is considerably more safe."

The safer, more agile nature of the Bat Bot could enable a wide range of applications. For instance, Bat Bots could serve as "aerial service robots at home or in hospitals to help the elderly or disabled by quickly fetching small objects, relaying audio and video from various distant locations without requiring hard-mounting of multiple cameras, and becoming fun, pet-like companions," Hutchinson told Live Science.

Multitasking robots

Another potential application for Bat Bots would be "to supervise construction sites," Hutchinson said. "The need for automation in construction through advances in computer science and robotics has been highlighted by the National Academy of Engineering as one of the grand challenges of engineering in the 21st century," he noted.

The dynamic and complex nature of construction sites has prevented the deployment of fully, or even partially, robotic and automated solutions to monitor them. "Keeping track of whether a building is put together in the right way and at the right time is an important problem, and it's not a trivial problem — a lot of money gets spent on that in the construction industry," Hutchinson said. Instead, Bat Bots could "fly around, pay attention and compare the building information model to the actual building that's being constructed," he added.

Bat Bots could also help inspect disaster zones and other areas. "For example, an aerial robot equipped with a radiation detector, 3D camera system, and temperature and humidity sensors could inspect something like the Fukushima nuclear reactors [in Japan], where the radiation level is too high for humans, or fly into tight crawl spaces, such as mines or collapsed buildings," Hutchinson said. "Such highly maneuverable aerial robots, with longer flight endurance and range than quadrotors have, will make revolutionary advances in monitoring and recovery of critical infrastructure such as nuclear reactors, power grids, bridges and borders."

Moreover, the Bat Bot could shed light on some of the mysteries of bat flight. Currently, researchers analyze how bats fly with video, but with the Bat Bot, researchers could develop better models of the aerodynamic forces that bats experience "beyond what can be observed with just the eyes," Hutchinson said.

The researchers noted that the Bat Bot cannot carry heavy objects yet, but future versions of the robotic bat could lead to "drone-enabled package delivery," Chung said.

Future research could achieve other aspects of bat flight, such as hovering or perching right side up or even upside down, the researchers said. Perching is more energy-efficient than hovering, "since stationary hovering is difficult for quadrotors in the presence of even mild wind, which is common for construction sites," Chung said.

RoboDragonfly: Tiny Backpack Turns Insect into a Cyborg

A first generation version of the backpack guidance system that includes energy harvesting, navigation and optical stimulation on a to-scale model of a dragonfly.

Credit: Charles Stark Draper Laboratory

Scientists look to flying animals — birds, bats and insects — for inspiration when they design airborne drones. But researchers are also investigating how to use technology to interact with, and even guide, animals as they fly, enhancing the unique adaptations that allow them to take to the air.

To that end, engineers have fitted dragonflies with tiny, backpack-mounted controllers that issue commands directly to the neurons controlling the insects' flight.

This project, known as DragonflEye, uses optogenetics, a technique that employs light to transmit signals to neurons. And researchers have genetically modified dragonfly neurons to make them more light-sensitive, and thereby easier to control through measured light pulses. [7 Animals That Wore Backpacks for Science]

Dragonflies have large heads, long bodies and two pairs of wings that don't always flap in sync, according to a 2007 study published in the journal Physical Review Letters. The study authors found that dragonflies maximize their lift when they flap both sets of wings together, and they hover by flapping their wing pairs out of synch, though at the same rate.

Meanwhile, separate muscles controlling each of their four wings allow dragonflies to dart, hover and turn on a dime with exceptional precision, scientists found in 2014. Researchers used high-speed video footage to track dragonfly flight and build computer models to better understand the insects' complex maneuvers, presenting their findings at the 67th Annual Division of Fluid Dynamics meeting, according to a statement released by the American Physical Society in November 2014.

DragonflEye sees these tiny flight masters as potentially controllable flyers that would be "smaller, lighter and stealthier than anything else that's manmade," Jesse Wheeler, a biomedical engineer at the Charles Stark Draper Laboratory (CSDL) in Massachusetts and principal investigator on the DragonflEye program, said in a statement.

A close-up of the backpack board and components before being folded and fitted to the dragonfly.

Credit: Charles Stark Draper Laboratory

The project is a collaboration between the CSDL, which has been developing the backpack that controls the dragonfly, and the Howard Hughes Medical Institute (HHMI), where experts are identifying and enhancing "steering" neurons located in the dragonfly's nerve cord, inserting genes that make it more responsive to light.

"This system pushes the boundaries of energy harvesting, motion sensing, algorithms, miniaturization and optogenetics, all in a system small enough for an insect to wear," Wheeler said.

Even smaller than the dragonfly backpack are components created by CSDL called optrodes — optical fibers supple enough to wrap around the dragonfly's nerve cord, so that engineers can target only the neurons related to flight, CSDL representatives explained in a statement.

And in addition to controlling insect flight, the tiny, flexible optrodes could have applications in human medicine, Wheeler added.

"Someday these same tools could advance medical treatments in humans, resulting in more effective therapies with fewer side effects," Wheeler said. "Our flexible optrode technology provides a new solution to enable miniaturized diagnostics, safely access smaller neural targets and deliver higher precision therapies."

Tiny, Underwater Robots Offer Unprecedented View of World's Oceans

A group shot of the M-AUEs in Jaffe’s lab, awaiting deployment.

Credit: Scripps Institution of Oceanography

Robots the size of grapefruits are set to change the way scientists study the Earth's oceans, according to a new study.

Though space is often known as the "final frontier," the oceans of our home planet remain much of a mystery. Satellites have played a big role in that divide, as they explore the universe and send data back to scientists on Earth. But now, researchers have developed a kind of satellite for the oceans — autonomous miniature robots that can work as a swarm to explore oceans in a new way.

For their initial deployments, the Mini-Autonomous Underwater Explorers (M-AUEs) were able to record the 3D movements of the ocean's internal waves — a feat that traditional instruments cannot achieve. Study lead author Jules Jaffe, a research oceanographer at the Scripps Institution of Oceanography, said current ocean measurements are akin to sticking a finger in a specific region of the water. [In Photos: The Wonders of the Deep Sea]

"We can move the finger around, but we're never in two places at the same time; so we basically have no sort of three-dimensional understanding of the ocean," Jaffe told Live Science. "By building this swarm of robots, we were in 16 places at the same time."

Each underwater robot is about the size and weight of a large grapefruit, Jaffe said. The bots are cylindrical and have an antenna on one end and measurement instrumentation on the other.

An artist's depiction of the near shore deployment of the robot swarm.

Credit: Scripps Institution of Oceanography

The swarm's first mission was to investigate how the ocean's internal waves moved. One of Jaffe's colleagues theorized that aspects of plankton's ecology is due to ocean currents pushing plankton together and pulling it back apart. However, scientists did not have the three-dimensional instrumentation capabilities to be able to verify those theories. Over the course of a few afternoons, Jaffe and his team deployed the M-AUEs in hopes of proving (or disproving) the theory.

"We could see this swarm of robots be pushed by currents, getting pushed together and then get pushed apart," Jaffe said. "It's almost like a breathing motion, but it occurred over several hours."

The theory was based on ocean physics, water density and internal wave dynamics, but the scientists had never seen the real-time movement of ocean water in 3D, Jaffe said.

And although their initial deployments were focused on the 3D mapping of internal wave dynamics, Jaffe said there are many other applications for the robot swarms.

For instance, with slightly different instrumentation, the robots could be deployed in an oil spill to help track the harmful toxins released. With underwater microphones, the swarm could also act as a giant ear, listening to whales and dolphins.

"We're not yet churning them out like a manufacturing facility, but we think we can answer a lot of questions about global ocean dynamics with what we have," Jaffe said of the couple of dozen robots the scientists have now. "And we are planning on a next generation, which hopefully would have more functionality and would maybe be even less expensive."

Details of the robot swarm were published online today (Jan. 24) in the journal Nature Communications.