Going into disaster scenarios, robots still have one major disadvantage: their inability to recover when they inevitably crash into things. Scientists, however, have taken a page out of the biology playbook, as they often do, to create a drone that can recover when it encounters various obstacles.
Think of a bird landing on a tree branch; to do so, you will likely have to bump into some smaller branches or leaves in the process of landing. But, your joints and soft tissue cushion these bumps in the road, and your feet are precisely built to lock into place without straining a muscle. When a drone chooses a similar route, having a lot of collisions on the way to its destination, it’s a bit more dramatic. “They don’t recover; they crash,” Wenlong Zhang, an associate professor and robotics expert at Arizona State University, said in a statement.
“We see drones used to assess damage from high in the sky, but they can’t actually navigate through collapsed buildings,” Zhang added. “Their rigid frames compromise resilience to collision, so colliding with poles, beams, pipes or cables in a wrecked structure is often catastrophic.”
Zhang is the author of a recent article published in soft robotics in which a team of scientists designed and tested a quadrotor drone with an inflatable frame, apparently the first of its kind. The inflatable frame acts almost like an inflatable suit, protecting the drone from the harsh consequences of crashing into a wall or other obstacle. It also provides the kind of soft tissue absorption needed for perching, the team’s next task.
[Related: Watch this bird-like robot make a graceful landing on its perch.]
After studying how the birds land and cling to branches with their clawed feet, the team developed a fabric-based bistable gripper for the inflatable drone. The gripper had two “rest states” without power, meaning it can stay open or closed without using power, and it reacts to landing shock by closing its little feet and forcefully gripping a nearby object.
“It can perch on almost anything. Also, the bistable material means you don’t need an actuator to provide power to hold your hanger. It just closes and stays closed without consuming power,” Zhang said in the statement. “Then, when needed, the gripper can be retracted pneumatically and the drone can take off.”
A more rugged type of drone is crucial for search-and-rescue scenarios when the path forward may be littered with debris, but the authors could also see this type of creation useful for monitoring wildfires or even exploring other planets.