Winged creatures such as birds, bats, and insects can only lift their own weight when flying. But Estrada and his colleagues from Stanford University and the Ecole Polytechnique Federale de Lausanne in Switzerland is looking at the practical approach taken by predatory wasps, which is taking a closer look at the ground. The group's bio-inspired approach to robotic experimentation is detailed in the latest issue of Science Robotics.
Photo: Laboratory of Intelligent Systems / EPFL
The "FlyCroTug" drones also represent an evolution for ground-based robots originally developed by David Christensen, a coauthor on the paper who is currently employed at Disney Research. By turning to a custom-built quadrotor drone design, the team created micro air vehicles that combines aerial mobility with greater pulling or pushing strength based on ground anchoring.
Each FlyCroTug drone has a special attachment to the end of a long cable that can be paid for and pulled back into a winch. That means the drones can be attached to an object, fly off, land, and anchor. What can be used to be a giant leap at a time for the drones, Estrada explained.
The anchoring mechanisms based on technologies from Stanford's Biomimetics and Dexterous Manipulation Lab also takes inspiration from natural design: microspines capable of attaching to rough stucco or concrete surfaces, and sticky gecko-inspired adhesives for attaching to smooth glass.
Having tiny drones that can explore cramped spaces and still open wide forces on their surroundings for search and rescue applications in military or military scenarios. For example, Estrada suggests that such drones could be used to deploy personal medical devices or to deploy personal medical devices to a remote location.
In one of the team's experiments, a FlyCroTug drone clung to an overhang has it pulled up a battery-powered camera to perform inspections of a collapsed building site at a military training facility outside of Geneva, Switzerland.
A second door-opening scenario required teamwork between two FlyCroTug drones. The first drone grabbed the door with a special grappling attachment and then anchored itself to the smooth glass door. The second drone slipped a door under the door and opened the door.
As impressive as this all sounds, the FlyCroTug drones still face serious limitations. Their current battery life is sufficient for just five minutes of flight, which severely limits what they can do. Complex and unknown environments would also require many versions of the drones with different attachments and anchor mechanisms for various surfaces. But the latter can not be a problem, if such flying robots could be made cheaply and be deployed as disposable drones.
Researchers have not yet developed such capabilities or artificial intelligence capabilities for such drones to operate even semi-independently, let alone in fully autonomous mode of human control. But Estrada believes that a teleoperation approach makes the most sense for near-future deployments of such technology.
"Humans can intuitively read a room and predict what surfaces might be [find] feasible paths to these locations, "Estrada says. "This could be combined with some low-level autonomy for maneuvers such as holding a position or grappling a handle."
