Where Current Drones Can't Go, Ones Inspired by Bats Can

Don't be fooled by the fog machine, spooky lights, and fake bats—the robotics lab at Massachusetts' Worcester Polytechnic Institute lab wasn't hosting a Halloween party. Instead, it's a testing ground for tiny drones that can be deployed in search and rescue missions even in dark, smoky, or stormy conditions, per the AP. "We all know that when there's an earthquake or a tsunami, the first thing that goes down is power lines," says Nitin Sanket, assistant professor of robotics engineering. "A lot of times, it's at night, and you're not going to wait until the next morning to go and rescue survivors," so "we started looking at nature." To wit, the scientists asked themselves: "Is there a creature in the world [that] can actually do this?"

• Sanket and his students found their answer in bats and the winged mammal's highly sophisticated ability to echolocate, or navigate via reflected sound. With a National Science Foundation grant, they're developing small, inexpensive, and energy-efficient aerial robots that can be flown where and when current drones can't operate.

• Last month, emergency workers in Pakistan used drones to find people stranded on rooftops by massive floods. In August, a rescue team used a drone to find a California man who got trapped for two days behind a waterfall. And in July, drones helped find a stable route to three mine workers who spent more than 60 hours trapped underground in Canada.
• But while drones are becoming more common in search and rescue, Sanket and researchers elsewhere want to move beyond the manually operated individual robots being used today. A key next step is developing aerial robots that can be deployed in swarms and make their own decisions about where to search, says Virginia Tech's Ryan Williams. "That type of deployment—autonomous drones—is effectively nil," he says.
• Williams tackled that problem with a recent project that involved programming drones to choose search trajectories in coordination with human searchers. Among other things, his team used historical data from thousands of missing-person cases to create a model predicting how someone would behave if lost in the woods.
• At WPI, Sanket's project addresses other limitations of current drones, including their size and perception capabilities. "Current robots are big, bulky, expensive, and cannot work in all sorts of scenarios," he said. By contrast, his drone fits in the palm of his hand, is made mostly from inexpensive hobby-grade materials, and can operate in the dark. A small ultrasonic sensor, not unlike those used in automatic faucets in public restrooms, mimics bat behavior, sending out a pulse of high-frequency sound and using the echo to detect obstacles in its path.
• "Currently, search and rescue robots are mainly operational in broad daylight," Sanket said. "The problem is that search and rescues are dull, dangerous, and dirty jobs that happen a lot of times in darkness."