Why a researcher is building robots that look and act like bats

Search and rescue missions often take place in areas that are difficult for humans to navigate due to extreme weather, rough terrain, or hazardous conditions such as smoke or dust.

A researcher at Worcester Polytechnic Institute (WPI) wants to send bat-inspired robots on these missions instead of humans.

Nitin J. Sanket, a professor at WPI, and his team have developed small flying robots that fit in the palm of a hand and use ultrasound — just like bats. These robots use artificial intelligence software to filter out noise from the ultrasound signals the devices pick up, allowing them to detect obstacles within a two-meter radius.

“Search and rescue is on foot,” Sanket told TechCrunch. “There are a lot of people who go on foot with flashlights in very harsh conditions and put their lives at risk to save others. We thought drones were the answer because they can cover a lot of ground very quickly. They can be agile and fast.”

Sanket has long been fascinated by aerial robots and drones and how the technology can be retrofitted for real-world situations. During his PhD program, his advisor challenged him to create the smallest robot possible, which sparked his research into taking cues from biology to build smaller machines.

“We had to rethink what a drone would be at that point, which is to go back to biology, because biology does that way better than we can today,” Sanket said. “How do insects or birds with extremely limited computing and not so good sensing do it? Their eyes aren’t that great, their brains are very small, but they’re still able to do these amazing feats of flight. So we started looking at it, and that’s what led to my PhD.”

Sanket built a robotic hive prototype consisting of small drones that could pollinate flowers. Despite his efforts, he realized that this application was likely a moonshot and started thinking about areas where biology-based robots could make a difference sooner, which led him to his current project.

For search and rescue robots, the main challenge was building something with the necessary sensors and flight technology without making the robot too big, expensive or power-hungry.

Sanket said they turned to the ultrasonic sensors used in automatic faucets because they require very little power. While this approach worked, the propellers they built into the robots created too much noise, which overloaded the sensor’s ability to detect obstacles.

To fix this problem, they turned back to bats.

“Bats have these special tissues in their noses, ears and mouths that adaptively change in thickness and density to regulate how they hear and chirp sound,” Sanket said. “We’re like, ‘Okay, that’s pretty cool.’ Can we do something like this? We designed a 3D printed structure to place in front of the robot, which essentially does the same [functionally, as] what a bat does, which is to change the shape of the sound itself.’

Now that they’ve gotten the robots to work, they’re working on their next challenge: improving their speed.

“We, as human beings, like to try to mimic a lot of things that the human brain does,” Sanket said. “We tend to forget how remarkable other animals are, which are much smaller than us. Especially insects and birds, which are much smaller, can really do remarkable feats of navigation, which I think we don’t often see. I think we need to think more like scientists than pure engineers.”