SoBAR Is a Soft-Body Inflatable Drone That Aims to Survive Collisions, Not Avoid Them

Researchers from Arizona State University and Hellenic Mediterranean University have developed a drone which they hope will take the sting out of unexpected impacts by literally bouncing back — and aim to see it used for emergency response and disaster recovery.

"We see drones used to assess damage from high in the sky, but they can’t really navigate through collapsed buildings," explains Wenlong Zhang, associate professor and corresponding author on the paper. "Their rigid frames compromise resilience to collision, so bumping into posts, beams, pipes or cables in a wrecked structure is often catastrophic. They don't recover; they crash."

That's where the team's new quadcopter design, SoBAR, comes in. While externally it looks like many other drones, it's designed to bounce back from crashes — literally — using an inflatable frame. To keep it stable when landed, the base of the drone also includes a clever gripper — allowing it to perch, bird-like, on almost any surface for observation or to conserve its batteries.

"We need to change our focus on avoiding environmental contact. Drones need to physically interact with their surroundings to accomplish a range of tasks," Zhang argues, in support of a bouncy drone over a smart one which can attempt to avoid collisions altogether. "A soft body not only absorbs impact forces to provide collision resilience; it also offers the material compliance necessary for dynamic maneuvers such as perching."

The perch gripper, inspired by birds, uses a fabric-based bistable grasper — meaning it only requires power when flipping between its open and closed states, allowing the drone to grasp onto a perch and remain there without consuming any energy. "The bistable material means it doesn't need an actuator to provide power to hold its perch," Zhang explains. "It just closes and stays like that without consuming any energy. Then when needed, the gripper can be pneumatically retracted and the drone can just take off."

The team's work has been accepted for publication in the journal Soft Robotics, with the online version available under open-access terms.