UAV updateFuture UAVs will emulate birds

Engineers at UC San Diego are mimicking the movement of bird wings to help improve the maneuverability of unmanned aerial vehicles (UAVs).

UAVs are often used for surveillance of a fixed target in military and civilian applications. In order to observe a stationary target, a fixed wing UAV must remain airborne over the object, thus expending energy for propulsion and reducing operational time. In addition, the aircraft may need to loiter at significant altitudes to avoid detection, and thus require complex sensors to observe the target far below. Rotary wing aircraft may be able to land on a perch for surveillance, but are generally less efficient for cruising flight than a fixed wing solution.

A fixed wing aircraft capable of spot landing on a perch (top of a pole, building, fence, etc.) would be an ideal solution capable of efficient cruising and versatile landing for longer surveillance missions. Because the target is nearby, simple sensors could be used onboard the perched aircraft.

A University of California, San Diego, release reports that the problem of perching has already been solved by nature. Birds routinely land on small surfaces, using wing morphing and flapping techniques. The UC San Diego engineers, led by mechanical and aerospace engineering professor Tom Bewley and graduate student Kim Wright, analyzed in slow motion several videos of birds landing to generate a working hypotheses for how wing morphing and flapping can be used for spot landing.

“One of the key behaviors observed in the birds was their use of wing sweep for pitch control in both forward flight and stalled landing approaches,” she said. “Birds can move their wings in a myriad of ways, providing a level of aerodynamic control that is unmatched by UAVs,” Wright said.

To verify their hypotheses, Wright and her team built a small remote controlled UAV with variable wing sweep and tested it using computer modeling, and an onboard microcontroller as a flight data recorder. Their initial testing validated the concept of using wing sweep for pitch control of the aircraft.

The biologically inspired aircraft design is similar in scale to the birds the engineers observed (barn owl, hawks, large parrots, crows) and has similar wing loading and airfoil characteristics. The fuselage and tail surfaces of the prototype UAV were primarily constructed from balsa wood and foam using standard hobby aircraft construction techniques. The wings were formed using composite construction utilizing carbon fiber, fiberglass, high density foam, and rip stop