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Harvard Launches Robot Moth

A robotic tobacco hawkmoth joins Harvard's collection of artificial insects

2 min read
Harvard robot moth
Image: Harvard Microrobotics Laboratory

Harvard researchers have been working on their robot bee for a really, really long time (in robot years). It’s impressively small, being bee-sized, but it turns out that it’s so small that it’s not realistic to expect it to fly with onboard power and computing in the near future. Plus, the flight dynamics of tiny insects like bees is significantly different from larger insects like butterflies and moths, which exhibit combinations of flapping, gliding, and soaring flight. To explore this, Harvard researchers have developed FWMAV, a novel insect-scale flapping-wing micro-air vehicle that’s just small enough to be called “micro” and just big enough to operate completely untethered.

The video makes it look like FWMAV has some trouble staying aloft, but the researchers told us that it can keep a stable altitude by flapping between 70 percent and 80 percent of the time. The wings are delicate, though, and when this particular clip was filmed (after 30 or 40 flight tests), the robot was a little bit beat up and wasn’t at peak efficiency.

FWMAV has a wingspan of 16 centimeters, and weighs just over 3 grams (almost half of which is the motor). It’s fully untethered, with onboard power, communication, and control systems. In overall dimensions and performance, it’s analogous to the tobacco hawkmoth. Flapping at 25 Hz, it can average about 4 g of thrust, more than enough to keep it airborne. The flapping action itself is generated by a folded carbon fiber transmission that converts the rotary motion of the motor into up and down motion of the wings, which are designed to flex over a 90 degree range to vary their angle of attack and improve aerodynamics in the same way that real insect wings do.

harvard robot mothA 3D model of the robot used for simulation.Image: Harvard Microrobotics Laboratory

The most obvious departure from the bioinspired design is in the tail, which is far more airplane-like than moth-like and required to keep the robot stable in yaw and roll. Real moths can do this using independent control of each of their wings, but since FWMAV doesn’t have this capability (yet), the tail is necessary. It also can’t take off by itself, and needs to be launched by catapult.

Relative to RoboBee, which can take off and hover and steer (and was learning to swim), FWMAV might seem a little primitive, but this paper represents just the first hardware validation. Researchers are already planning aerodynamic improvements, tail actuation, and a redesign to allow independent control over each wing. They’re also looking forward to taking the robot outside of the motion capture area that it’s currently restricted to, with the goal of closed-loop flight in bigger, more open areas.

“Development of a 3.2g Untethered Flapping-Wing Platform for Flight Energetics and Control Experiments,” by Michelle H. Rosen, Geoffroy le Pivain, Ranjana Sahai, Noah T. Jafferis, and Robert J. Wood from the Harvard Microrobotics Laboratory, was presented this week at ICRA 2016 in Stockholm, Sweden.

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The Bionic-Hand Arms Race

The prosthetics industry is too focused on high-tech limbs that are complicated, costly, and often impractical

12 min read
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A photograph of a young woman with brown eyes and neck length hair dyed rose gold sits at a white table. In one hand she holds a carbon fiber robotic arm and hand. Her other arm ends near her elbow. Her short sleeve shirt has a pattern on it of illustrated hands.

The author, Britt Young, holding her Ottobock bebionic bionic arm.

Gabriela Hasbun. Makeup: Maria Nguyen for MAC cosmetics; Hair: Joan Laqui for Living Proof
DarkGray

In Jules Verne’s 1865 novel From the Earth to the Moon, members of the fictitious Baltimore Gun Club, all disabled Civil War veterans, restlessly search for a new enemy to conquer. They had spent the war innovating new, deadlier weaponry. By the war’s end, with “not quite one arm between four persons, and exactly two legs between six,” these self-taught amputee-weaponsmiths decide to repurpose their skills toward a new projectile: a rocket ship.

The story of the Baltimore Gun Club propelling themselves to the moon is about the extraordinary masculine power of the veteran, who doesn’t simply “overcome” his disability; he derives power and ambition from it. Their “crutches, wooden legs, artificial arms, steel hooks, caoutchouc [rubber] jaws, silver craniums [and] platinum noses” don’t play leading roles in their personalities—they are merely tools on their bodies. These piecemeal men are unlikely crusaders of invention with an even more unlikely mission. And yet who better to design the next great leap in technology than men remade by technology themselves?

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