By Alissa D’Gama ’11, thurj Staff
Professor Robert Wood’s creations have been featured in an exhibit at the Museum of Modern Art, on two Discovery Channel series, and in Time Magazine. When you walk into his Harvard lab at 60 Oxford Street—a building beyond the boundary of most undergaduates’ travels—you find yourself amid the hustle and bustle of undergraduates, graduate students, and postdocs peering through microscopes at actuators, using lasers to create air frames, and tweaking mechanical wings and transistors.
Yet the most excited of all is Professor Wood himself, walking around and peering over the shoulders of his students, making suggestions and sharing in their enthusiasm.
What’s so special about his product? It is the first at-scale robotic insect with sufficient thrust to take off—in other words, fly—with external power.
Getting Ready for Takeoff
Professor Wood’s journey to flight began when he entered graduate school at the University of California, Berkeley. With a background in electrical engineering, Wood hoped to find a research project in his interest as well as “inherently interesting of itself.”
At that time, one of the first efforts to create a robotic insect was starting up, and the project caught Wood’s attention—yet what he initially though he would work on was not what he ended up researching. Wood was geared towards working on controlling the fly, but the fly didn’t exist yet!
“My adviser said, ‘You have to build the fly first,’” said Wood. “I had to switch gears and become a different sort of engineer.”
After receiving his PhD, Wood carried over his microrobotics work to Harvard where he was appointed as an Assistant Professor of Electrical Engineering and Computer Science. The catalyst behind his research projects evolved from material design—saying “I want to make this shape, so how do I do that?” and lead down two primary paths.
“One is microrobotics, creating particular robotic insets, things that fly and crawl that are inspired by various aspects of arthropod morphology and control materials,” said Wood. “The second is soft robotics, creating both autonomous robots which are capable of locomotion and also creating new materials with inherent compliance like artificial muscles and embedded sensors.”
Inherent compliance in wings refers to their “degree of floppyness” all insect wings have some degree of compliance due to aerodynamic and inertial loads experienced in flight. Wood hopes to understand why insects have this compliance and how it benefits them during flight.
Soft robots aren’t like the tin-can creations from comic books—rather, they are robots that can easily change their shape and size and are made from flexible materials.
Unlike those working on creating human robots—sensationalized on the big screen in movies like I, Robot, Wood has had to focus on many aspects larger-scale roboticists take for granted and that can’t be applied directly on a smaller scale to robotic insects.
“Instead of jumping right to questions of control or behavior we have to start from nothing and do everything from scratch,” said Wood.
Fly, Robot, Fly
In 2007, Wood’s fly took flight for the first time, fixed to guide wires that allowed only vertical motion. The robotic fly was integrated from four components: an actuator (the flight muscles), transmission (thorax), an air frame (exoskeleton), and wings. Weighing in at only 60 mg with a 3 cm wingspan, the tiny mechanical creature could move freely in the vertical direction with a trajectory nearly identical to biological counterparts.
This robotic fly can be put together in under a week – a user-friendly advancement.
“In the past the fabrication methods we used took a great deal of skill and time,” said Wood. “That was fine when it was really just me making them, but when you get new students involved nobody has this very esoteric skill set that they wouldn’t use for anything else.”
Now the emphasis is on the empirical portion of the research—building structures and trying to characterize their performance to “fill in the empty pieces” of previous models. As Wood noted, once his lab demonstrated the first successful flight, “that opened up a dozen different paths—we have an endless supply of things we need to study.”
He hopes to develop robotic insects that can fly in multiple dimensions (rather than solely vertically) without an external power source and with the ability to work together in groups.
His project is funded by the U.S. Defense Advanced Research Projects Agency, who hopes that at-scale robotic insects can be used as spy technology during wartime or as a means to locate survivors trapped in hazardous environments.
But Wood said he encouraged people to look beyond the face value.
“Anyplace you wouldn’t want to put a human or an animal, there’s a big class of scenarios for application of a mobile robot,” said Wood. “And in reality, we’re developing new techniques for fabrication and actuation at an interesting scale which individually could be applied to understand many different phenomena, for example, the fluid mechanics of different wings.”
As evident when visiting the lab, Wood tried to spend several hours at the lab each day interacting with the students, as well as scheduling weekly lab meetings for the lab as a whole and for different subgroups. When he’s not tinkering with the robotic flies themselves—he says he will often embark on his own little project that will help out one of his students; he works to raise money and make sure everyone is happy.
“The nice thing about a robotics lab is that it’s very multidisciplinary—we have students who are studying mechanical engineering, electrical engineering, computer science, bioengineering…everything,” said Wood. “So when you’re stuck, you have a lot of different voices from a lot of different areas.”
And by putting all those voices together, Wood and his students have created a robotic fly that is, indeed, ready for take-off and may one day search out soldiers injured in the battlefield or miners trapped underground.
As Prof Wood’s website relates: “Remarked one unimpressed Yale researcher: ‘Leave it to the Harvard fellows to invent new and exciting ways to be irritating.’”