Could this robot bat one day edge out quadrotors as the drone of the future?

Researchers have developed a robotic bat that flies just like the real mammal and features many of its musculoskeletal structures.

While bats have inspired flying-machine designs as far back as Leonardo Da Vinci, their complex joint structure and wing movements make them extremely difficult to simulate.

However, scientists from Caltech and the University of Illinois at Urbana-Champaign (UIUC) have now designed a robotic bat with silicon wings that can mimic many of a real bat's flight mechanics. The Bot Bat, or B2, features on the cover of the current issue of Science Robotics.

"This robot design will help us build safer and more efficient flying robots, and also give us more insight into the way bats fly," said Soon-Jo Chung, associate professor of aerospace and Bren Scholar in the Division of Engineering and Applied Science at Caltech, and Jet Propulsion Laboratory research scientist.

As the researchers note, bat wings are far more sophisticated than birds and insects, with the ability to morph courtesy of 40 different types of joints that support a higher degree of flexibility and offer bats their unrivaled agility.

Their robot bat weighs 93gm (3.3oz) with a wing span of 30cm to 40cm (11.8 to 15.7 inches), making it similar in size to a fruit bat.

It uses a subset of a real bat's joints in the arm wings and legs, with the bones and joints covered by a 56-micron thick silicon-based membrane for wings.

The wings, which are capable of about 60 percent of a bat's flight kinematics, are connected to a motor and onboard computer, as well as wireless communications units.

While the bat can automatically stabilize in flight, Spectrum IEEE notes that the enormous challenge of controlling the bat's flight path was solved by using a closed-loop feedback. The researchers tested this system with cruise flights, bank turning, and sharp diving maneuvers, which can be seen in the demonstration video.

Apart from improving energy efficiency, why build a robot bat when quadrotor drones are cheap and capable of agile flight? With numerous incidents to back up their point, the researchers contend that quadrotors are dangerous to humans. Plus they're noisy.

"In contrast, the compliant wings of a bat-like robot flapping at lower frequencies, 7Hz to 10Hz versus 100Hz to 300Hz of quadrotors, are inherently safe, because their wings comprise primarily flexible materials and are able to collide with one another, or with obstacles in their environment, with little or no damage," the researchers write.

The researchers are keen to see the bat bot being used for construction site inspection, as well as disaster relief and surveillance, according to Spectrum IEEE.