EDITOR'S NOTE: DESIGN + BIOLOGY = BUGS
by Chee Pearlman
A quick glance through the current issue could lead one to believe that we at I.D. have gone a bit buggy. More than a bit, in fact, by devoting this issue to the subject of bugs. Bugs? Yes, we were bitten and smitten by bugs, and here's how it happened:
First, we wandered into the movie Microcosmos, an exquisite live-action narrative about a day in the life of a community of insects. The movie is not extraordinary merely in its focus on the drama of these creatures' existence, but also for the years that went into its making and the battery of equipment specially designed in order to film this micro-universe. (I confess to seeing the movie three times, right in the second row where you can really commune with the protagonists.)
Then, at last February's TED conference, we met up with the ebullient bug man, Dr. Robert Full, whose investigations into the motion mechanics of creepy crawlies will inform the next generation of robot designs for IS Robotics and Rockwell. In our report, senior writer Peter Hall encounters Dr. Full's menagerie of cockroaches, poisonous centipedes and scorpions some of the most remarkably designed moving life forms on earth. Each, as Full has shown, has plenty to teach creators of machines designed to navigate land mines or otherworldly environments.
It was about this time that we realized that Hollywood was becoming as alive to bugs as we were. A spate of digitally designed movies with insects in starring roles are in the pipeline from animators at Pixar, Dreamworks and Tippett Studios. The last has produced tour-de-force sequences of an especially mean class of Warrior bugs, managing to key directly into some of our worst cultural fears about insects.
After that, the horse was out of the barn, to mix our animal metaphors. We were on to bugging devices, computer bugs and - how could we miss the cute new VW bug, which will come onto the market next year. What's fascinating, scary and little known about the VW beetle is that the "people's car" was originally designed, in part, by Hitler. ("It should look like a beetle," he said in 1934, "for we need look no further than nature to find out what streamlining is.") Contributor Phil Patton takes us through a 65-year time line of the Love Bug's remarkable history.
There was no end to the sources of inspiration for this issue, but we owe a particular debt of gratitude to Dr. Thomas Eisner, a leading researcher and biologist who took time out from this summer's peak bug-studying season to write our introductory essay. When I contacted him to ask whether he agreed that bugs were the embodiment of great design, his response was rapid: "Insects are designed for success," he said enthusiastically. "They won't take over the world. They own it now!" That's when we knew we were onto something. Enjoy.
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Secrets of Motion
A new generation of robots is being modeled after the mesmerizing maneuvers of cockroaches and millipedes. Could they soon roam Mars? I.D Magazine, Sept/Oct 1997.
By Peter Hall
Filmed under a high intensity light and played back in slow motion, the glowing legs of a poisonous centipede dance with a fearful symmetry. Its six-inch-long body undulates like a snake, with the legs inside each curve of the torso taking turns to strike the ground and propel the body forward. At full speed, the dance comes close to flight: only 3 of the centipede's 44 legs are on the ground at any one time.
Revelatory footage of nature's most loathsome creatures doesn't just serve to fascinate the TV nature-show-viewing public. When the sequence - from a Discovery Channel show was shown as part of a presentation at the TED conference in Monterey last year, several design educators extended invitations for follow-up lectures at their schools. They hadn't missed the fact that the presenter of the centipede's leggy ballet, Robert Full, of the University of California in Berkeley, is a bubbling fount of biological design inspiration. But the invitations were all tactfully declined. Full is also possibly the busiest bug man on earth.
A broad, effusive, 39-year-old Homo sapien from Buffalo, New York, Full is the director of UC Berkeley's Poly-PEDAL laboratory (the acronym PEDAL stands for performance, energetics and dynamics of animal locomotion), which studies the mechanics and physiology of creepy crawlies. His distinctly uncreepy, warm-blooded and media-friendly enthusiasm for bugs has landed him appearances on the Discovery Channel, the Today Show, in a variety of magazines and even some unwarranted attention in the National Enquirer. He was consulted on the making of animated bugs for RAID commercials and Pixar's upcoming movie A Bug's Life and has advised on the creation of animatronic bugs in the recent Miramax release, Mimic. But his most intriguing collaboration has been with the people who design autonomous vehicles with artificial intelligence: the Poly-PEDAL lab's findings are influencing a whole new generation of robots.
Conversations with Bob Full are held preferably by e-mail, but with a word of caution. He confesses to occasionally consigning the entire contents of an overbrimming inbox to the trash. One can see why. A question that twangs Full's pedagogical heartstrings received a reply several pages long. This is a jackpot for the recipient: Full-mail is not littered with scientific jargon, but with catchphrases, emphatic punctuation and descriptive analogies that even a mental millipede could understand.
The Poly-PEDAL lab's favorite subjects, arthropods, are creatures Full likes to distinguish with scorpions, centipedes, millipedes and cockroaches; any one of over a million species of invertebrates with segmented bodies, jointed limbs and external skeletons. Full maintains that he has no particular fondness for them, but believes after the Danish physiologist August Krogh - that their relatively simple muscles and skeletons contain general architectural principles for all animals and, by extension, for the design of robots. "I think, like most people, that bugs are actually disgusting," he says. "But they are simply extraordinary at telling us the secrets of nature." This philosophy yields a conservationist refrain, "diversity enables discovery." Strange and disgusting creatures must be preserved, argues Full, because they can lead to unanticipated discoveries that change the way we interact with our environment. "It pains me to see things become extinct," he says, "because that's a wonderful set of design ideas that are gone. Every organism has a story to tell."
RUN, ROACHES, RUN
At the lab, nature's crunchy creatures are put through a series of tests in torturous-looking contraptions. Roaches and crabs run on force-measuring platforms, Plexiglas stairs and treadmills in boxes that measure oxygen consumption. Tiny wires are placed into tiny muscles to determine when they are active. Our friend the poisonous centipede, meanwhile, is put in an ingenious "Jell-O trap" a long acrylic box with a gelatin-coated floor layered over two polarizing filters that are illuminated from beneath by a high-intensity light. The construction examines the forces the centipede generates when running. As each of the creature's feet strikes the Jell-O, the opaque surface is disrupted, allowing light to shine through at the same specific angle. The stronger the force of the leg, the brighter the light. On film, the effect is startling: the monstrous, jawed centipede appears to be creating stars with it's tiptoes.
The lab's choicest findings are relayed to the public as a series of astounding revelations of nature. Full's students notified the Guinness Book of World Records that the world's fastest land insect is a cockroach, which moves at 50 steps a second (the equivalent of humans running at 200 miles per hour). At top speeds, the roach rears up on its hind legs and runs like a bipedal human. Another feature shared by cockroaches and humans is the amount of mechanical energy we (along with dogs, horses, crabs, lizards and mice) use per pound of body weight when we walk or run.
Particularly startling is the manner in which creatures with six or more legs move. Previous theories had it that they trundled along rather like a wheel, placing one leg down after another at a regular pace. Under observations at the Poly-PEDAL lab, however, it emerged that the arthropods propel their legs in alternating tripods, with two legs down on one side, one leg down on the other, maintaining an impressive stool-like stability in motion. Most significantly, the legs of a running roach, crab, centipede and human do not move at a smooth, constant speed like wheels, but like pendulums when they walk and springs when they run, bending and bouncing, accelerating and decelerating. The tendons in our legs, in other words, function like energy-efficient pogo sticks, storing and releasing energy as they go.
DESIGN LESSON FROM LOW LIFES
About six years ago, Full got together with a group of researchers in robot development, including Rodney Brooks and Mark Raibert from the Massachusetts Institute of Technology's Artificial Intelligence Lab. Brook's lab had been working on an array of autonomous vehicles, or artificial creatures, for traversing difficult and hazardous terrains, such as the surface of Mars. Raibert's Leg Lab, meanwhile, had been building a series of one-, two- and four-legged hopping mechanisms that moved with an eerie naturalism. (They were accordingly cast, as robots, in a bit part with Sean Connery in the 1993 film, Rising Sun.) The contract between Brooks's and Raibert's robots was revealing. The former were very stable and moved very slowly with back-and-forth leg movements and little up-and-down oscillation of the body. Raibert's robots, on the other hand, were capable of extraordinary mechanical feats running at 13 mph, leaping over obstacles and climbing simplified stairs but they fell over when they were not moving.
Balance, as biologists, engineers, ecologists and Yoga enthusiasts all agree, is the key to moving forward. But Raibert had demonstrated that moving forward is also the key to balance. His robots were built on the pendulum/pogo stick principle. "I would never have guessed that many-legged sprawled postured animals would move dynamically by bouncing, " says Full. "Once we discovered this in several species, we looked at Raibert's work very carefully. Quire simply, he is a genius. He showed the importance and beauty of dynamic-legged locomotion."
A series of collaborations began. Full and Raibert decided to test the theory that insects "bounced" by building a computer simulation of a six-legged creature. Faithfully copying the Poly-PEDALists's detailed account of a cockroach's leg structure and positions during movement, the Leg Lab team (and subsequently Raibert's firm, Boston Dynamics) created 3-D computer renderings of a roach that resembled a hemisphere on legs. Sure enough, it bounced, and moved remarkably like New York's most reviled insect. Raibert's lab was also able to establish how much the muscles controlled the leg and the extent to which the tendons stretched. "Almost nothing is known about how people or animals control themselves," says Raibert, "and watching them doesn't always tell you how they work."
At the same time, Brooks and Raibert saw how Full's insight and amassed data on the design advantages and flaws of the roach and other creatures could influence their mechanical creations. "Seeing his critters," says Raibert, "has provided huge motivation." An early exploration of Poly-PEDAL findings was a bouncing, six-legged terrestrial robot powered by compressed air, built at Brooks's lab by researcher Mike Binnard. He called it Boadicea, after the fearsome queen of Britain who defeated the Romans in the first century A.D. While its lumbering, comical movements - which can be viewed in a series of mini-movies on the MIT Web site - bear little relation to the motions of Boadicea's thundering chariot, they do come several steps closer toward an approximation of a cockroach's dynamic. Like the roach, and unlike earlier robots, Boadicea's legs overlap each others' workspaces as they move, allowing for longer strides and therefore faster movement. It also strives to replicate the dynamic and static stability of a six-legged creature, such that three legs are always on the ground, forming a tripod.
RISE, ROBOTS, RISE
Champions of the robotic leg will point out that about half of the earth's landmass is inaccessible to a wheeled vehicle, and that's not counting the rest of the planets: A legged robot might have an easier time sightseeing on Mars than the wheeled Sojourner Rover. Legs often do less damage than wheels. A team at Ohio State University developed an "adaptive suspension vehicle" that showed how a legged tractor might pick its way gingerly through crops rather than flatten paths through wheatfields.
Such projects are no longer confined to the realm of academia. The Poly-PEDAL lab is collaborating with companies like Rockwell and IS Robotics, a commercial firm founded by Rodney Brooks, on commercial robots for a variety of uses, including medical and hazardous clean-up jobs. For IS Robotics, Full's team provided videotapes of crabs roving on beaches as references for the design of an amphibious six-legged vehicle named Ariel, which is designed to find landmines in the surf zone by moving over sand and underwater. Following the Poly-PEDAL lab's suggestions, Ariel adopts the flat orientation of a crab's body and leg design to minimize drag, and a variable stance width for high stability and high bottom clearance.
It's not that nature - or Full - have all the design answers. The idea that gazelles or ghost crabs are objects of perfection is a popular misconception. Evolution marches not toward perfection, but aims at the "just good enough" principle, such that many animals are constrained by their history. Full likes to use an automotive design analogy: Animals must make small changes in what their ancestors left them, like trying to modify a used car," he says. 'Humans can create a new car from scratch, using different designs and materials." With the design of Ariel, for instance, the crab's various efforts to avoid being flipped over by waves could be happily ignored by making the robot invertible, a distinctly non-biological solution.
Are six legs better than four, three or two, or even wheels? Some experts, such as Robert Ringrose, an MIT graduate student who worked on the roach simulation, believe that fewer legs is better for speed and maintenance. "I see adding more legs as moving back," says Ringrose. "Four legs gives you more pieces to break. And consider how fast an ostrich can run." Even Raibert is reluctant to say that the Sojourner Rover would have fared better with legs, given the current state of the technology. 'When you take into account the competing demands on a Mars mission, such as reliability, cost and communication, they're doing a magnificent job," he says.
In Full's view, however, a six-legged paradigm holds the key to the future, bringing speed and maneuverability to stable robots. The next robotic generation will fuse the static stability of the Sojourner Rover (it doesn't fall over when it stops) with the dynamic stability of a Raibert hopper. "Bugs have both!" says Full. "Nature is telling us that the bouncing six-legged design will result in the most maneuverable land vehicles ever built. "I cant wait to see them."
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