Researchers at Yale’s Grab Lab aren’t about to let the nuances of rotary-wing flight restrict what unmanned aerial vehicles can do. A team there has developed a hand-like modular grasping and manipulation platform that can be fitted to the bellies of UAVs to provide them with extra functionality without overly taxing their flight capabilities.
Aerial vehicles that could pick up and carry objects for their human handlers are generally of the vertical take-off and landing (VTOL), which means they are generally small rotary-wing aircraft (helicopters). But manipulating payloads with helicopters isn’t as easy as it sounds. The many variables acting on remotely piloted rotary wing aircraft make them difficult to land precisely, and payloads with uneven weight distribution can make the aircraft unstable.
To circumvent these issues, Grab Lab engineers created their manipulator with a single motor that controls all four “fingers” simultaneously. The fingers are made of polymers that are both flexible and soft, so they don’t transfer contact forces directly to the airframe, helping the UAV remain stable as it picks up an object. The “hand” is also adaptive, allowing it to passively conform to the shape of the object while still getting a good grip.
The result: a robot hand that can snatch anything from a box to your buddy’s beer without requiring the aircraft to land in a precise position over the object or causing flight instability. Presently the Yale aircraft can lift almost 4.5 pounds and is equipped with a battery of sensors like an inertial measurement sensor, a camera, and a height-above-ground sensor that help it carry out its touchy-feely work. It’s easy to imagine automated UAVs of this type someday being used in a variety of roles, from military supply chain and search and rescue missions to basic commercial freight applications.