Robotic bird flies at Pack Expo 2012
Dynamic demos have become a popular draw at technology shows, often presenting attendees with useful innovations. A case in point was the recent showing at Pack Expo of Festo Corp.’s “SmartBird”—a bionic, lifelike herring gull replica capable of autonomous flight via remote control. Development of SmartBird is a continuation of the company’s work that emulates nature, with the potential to yield new solutions translatable into industrial products.
The study of nature to derive insights into more efficient control technologies has been ongoing at Festo for some time. Part of the company’s Bionic Learning Network, such development projects are intended to yield new approaches and solutions for automation. The SmartBird project had the objective to “decipher the flight of birds in an energy-efficient technical adaptation of the natural model,” according to Festo. It represents a two-year development with university partners.
SmartBird implements true ultra-lightweight construction: Polyurethane foam skin was applied over a carbon-fiber skeleton to yield a model weighing 0.45 kg (about 1 lb). The replica has a 2-m (6.6 ft) wingspan and 1.07-m torso length, making it substantially larger, but less than half the weight of an average male herring gull. SmartBird can take off, fly, and land autonomously with wings that beat up/down and also twist for better flight efficiency. The inner portion of the dihedral (gull) wings provides lift, while the outer torsionally flexible part supplies thrust.
Flight power comes from a brushless servo motor that produces wing flapping motion through a gear and lever mechanism. There is also head and tail motion, provided by two brushless digital servo units. Miniature servo motors at the wing tips provide torsion for wing warping. This allows directing the wing’s leading edge into a positive angle of attack during the upward flapping stroke, then changing to negative angle of attack for a brief part of the stroke cycle to enhance thrust. An onboard electronics unit, using a 32-bit microcontroller, synchronizes the various wing, torso, and tail movements. Wing flapping frequency is variable for speed control, but the flapping motion has constant amplitude.
Power requirement is 23 W for takeoff and 12 W in flight, supplied by a lithium-polymer battery. SmartBird is controlled by a small remote radio unit within the sight range of about 2 km. Maximum flight speed is 40 km/h (nearly 25 mph) and ceiling height is 500 m.
SmartBird was first shown at the Hannover Industrial Fair in 2011 and is one of four prototype birds in existence worldwide. An anecdotal note: During one of SmartBird’s numerous outdoor flight demos, a flock of seagulls reportedly become curious about SmartBird and proceeded to swarm and squawk around this “strange relative.”
Among potential benefits expected from this project are advances in understanding flow behavior, remote condition monitoring in real time, energy efficiency, and lightweight design of products, Festo noted.
– Frank J. Bartos, PE, is a Control Engineering contributing content specialist. Reach him at firstname.lastname@example.org
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