Ben-Gurion University of the Negev (BGU) researchers announced on Monday that they have developed the first experimental robot drone that flies like a typical quadcopter, drives on tough terrain and squeezes into tight spaces using the same motors.
The hybrid flying sprawl-tuned autonomous robot (FSTAR) can fly over obstacles or run underneath them. It also adjusts its width to crawl or run on flat surfaces, climb over large obstacles and up closely-spaced walls, or squeeze through a tunnel, pipe or narrow gaps.
It can run on the ground at a speed of up to eight feet per second which, combined with low energy consumption using the same motors, makes FSTAR ideal for a broad range of applications that may require longer work time, BGU researchers said in a 20 May press statement.
Possible commercial uses, according to the researchers, are package deliveries since FSTAR can quickly fly to a target zone and then drive using its wheels safely and quietly to reach the recipient's doorstep. FSTAR can also be used for search and rescue applications as it can fly over various obstacles and crawl between or underneath cracks where a regular drone cannot fly.
The robot can also be used in agriculture, maintenance, cleaning, filming, and entertainment, as well as law enforcement and anti-terrorist applications.
FSTAR will be introduced at the International Conference on Robotics and Automation 2019 in Montreal on 21 May. It was developed in the BGU Bio-Inspired and Medical Robotics Lab by Prof. David Zarrouk, senior lecturer in BGU's Department of Mechanical Engineering, and head of the Bio-Inspired and Medical Robotics Lab and his graduate student, Nir Meiri.
In a related development, Purdue University researchers said on Monday that they have engineered flying robots that behave like hummingbirds, trained by machine learning algorithms based on various techniques the bird uses naturally every day. This means that after learning from a simulation, the robot “knows" how to move around on its own like a hummingbird would, such as discerning when to perform an escape maneuver.
Artificial Intelligence (AI), combined with flexible flapping wings, also allows the robot to teach itself new tricks. Even though the robot can’t see yet, for example, it senses by touching surfaces. Each touch alters an electrical current, which the researchers realized they could track.
“The robot can essentially create a map without seeing its surroundings. This could be helpful in a situation when the robot might be searching for victims in a dark place – and it means one less sensor to add when we do give the robot the ability to see," said Xinyan Deng, an associate professor of mechanical engineering at Purdue, in a 20 May press statement.
Researchers have been trying for years to decode hummingbird flight so that robots can fly where larger aircraft can’t. In 2011, the company AeroVironment, commissioned by DARPA, an agency within the U.S. Department of Defense, built a robotic hummingbird that was heavier than a real one but not as fast, with helicopter-like flight controls and limited maneuverability. It required a human to be behind a remote control at all times.
Further study on the physics of insects and hummingbirds allowed Purdue researchers to build robots smaller than hummingbirds – and even as small as insects – without compromising the way they fly. The smaller the size, the greater the wing flapping frequency, and the more efficiently they fly, Deng says.
The robots have 3D-printed bodies, wings made of carbon fiber and laser-cut membranes. The researchers have built one hummingbird robot weighing 12 grams – the weight of the average adult magnificent hummingbird – and another insect-sized robot weighing 1 gram. The hummingbird robot can lift more than its own weight, up to 27 grams.
Designing their robots with higher lift gives the researchers more wiggle room to eventually add a battery and sensing technology, such as a camera or GPS. Currently, the robot needs to be tethered to an energy source while it flies – but that won’t be for much longer, the researchers say.
The robots could fly silently just as a real hummingbird does, making them more ideal for covert operations. And they stay steady through turbulence, which the researchers demonstrated by testing the dynamically scaled wings in an oil tank. The robot requires only two motors and can control each wing independently of the other, which is how flying animals perform highly agile maneuvers in nature.
“An actual hummingbird has multiple groups of muscles to do power and steering strokes, but a robot should be as light as possible, so that you have maximum performance on minimal weight," Deng said.
Robotic hummingbirds wouldn’t only help with search-and-rescue missions, but also would allow biologists to study hummingbirds more reliably in their natural environment through the senses of a realistic robot. “We learned from biology to build the robot, and now biological discoveries can happen with extra help from robots," Deng said.