Engineers build bat-inspired robot drone

Engineers have been increasingly looking to nature to help design some of the most advanced robots.

Mechanical masterminds at Caltech and the University of Illinois at Urbana-Champaign were inspired by the flight capabilities of bats and designed a robot drone — the Bat Bot — with integrated bat-like mechanisms enabling the robot to soar, swoop and dive much like the biological mammal.

Soon-Jo Chung, associate professor of aerospace and Bren Scholar at Caltech, holds the Bat Bot. Credit: Caltech

In nature, bats have unparalleled agility and complex wing motions. Researchers were tasked with recreating these features in a self-contained robotic bat with soft, articulated wings.

Bats have an incredibly sophisticated powered flight mechanism, which includes wings that change shape. Their flight mechanism involves several different types of joints that interlock the bones and muscles to one another, creating a musculoskeletal system that is capable of movement in more than 40 rotational directions.

Soon-Jo Chung, associate professor of aerospace at Caltech, developed the robotic bat, along with his former postdoctoral associate Alireza Ramezani from UIUC and Seth Hutchinson, a professor of electrical and computer engineering at the UIUC and Ramezani’s co-advisor.

The Bat Bot weighs only 93 grams and is shaped like a bat with a roughly one-foot wingspan. It is capable of altering its wing shape by flexing, extending and twisting at its shoulders, elbows, wrists, and legs. The researchers were challenged when it came to creating wing that were able to change shape while flapping, much like biological bats do. Conventional lightweight fabrics, like nylon and Mylar, are not stretchable enough. Instead, the team developed a custom ultra-thin (56 microns), silicone-based membrane that simulates stretchable, thin bat wings.

“Our work demonstrates one of the most advanced designs to date of a self-contained flapping-winged aerial robot with bat morphology that is able to perform autonomous flight,” Ramezani says.

Bat-inspired aerial robots have the potential to be significantly more energy efficient than current flying robots because their flexible wings amplify the motion of the robot’s actuators. When a bat—or the Bat Bot—flaps its wings, the wing membranes fill up with air and deform. At the end of the wings’ downward flapping motion, the membranes snap back to their usual shape and blast out the air, creating a huge amplification in power for the flap.

The robot drone design has potential applications for use in extreme environments, where there is the possibility that traditional quadrotor drones can collide into objects or people, causing damage or injury.

“This robot design will help us build safer and more efficient flying robots, and also give us more insight into the way bats fly,” says Chung and Bren Scholar in the Division of Engineering and Applied Science at Caltech, and Jet Propulsion Laboratory research scientist.

The study is titled “A Biomimetic Robotic Platform to Study Flight Specializations of Bats.” This research was funded by the National Science Foundation’s National Robotics Initiative.

www.caltech.edu