Volume 5, Issue 36 April 2008
A Crucible for Biological Inspiration
CiBER founder and director Robert Full gains insights into the mechanics of animal locomotion from creatures ranging from cockroaches to geckos. Image: courtesy Berkeley NewsCenter
To enter the office of Robert Full is to meet a menagerie of animal-inspired robots and the creatures that inspired them. On one wall hangs a likeness of crablike Ariel, who can wade through surf and, if bowled over by a breaker, can right herself again. Behind another frame is a likeness of RHex, able to scuttle across hills and boulder fields on six springlike legs. From a third frame hangs the likeness of mechanical gecko named RiSE, which scales buildings and panes of glass on feet bristling with microscopic sticky hairs.
These marvelous machines were inspired by the discoveries of Full, a Berkeley professor of Integrative Biology, in his collaborations with engineers, mathematicians, and scientists from other fields. "As human technologies take on more of the characteristics of nature, nature becomes a more useful teacher," Full says.
Full attributes the development of his remarkable mechanical progeny to his cross-disciplinary partnerships. "We think science has to be interdisciplinary now to really be cutting edge," Full says. "The collective discoveries can go beyond what any one group could do. But you don't just throw people together and expect it to happen. The collaborations will break down."
CiBER encourages the study of animal motion by interdisciplinary teams of biologists, engineers and other scientists. The approach has already yielded an impressive array of climbing, running and wading robots such as RiSE, a climbing robot that clings to walls using technology based on gecko feet. Image: courtesy Robert Full
Full and UC Berkeley have launched a center expressly geared to encourage partnerships among biologists and scientists of different stripes. The Center for Interdisciplinary Bio-inspiration in Education and Research (CiBER) already counts more than two dozen faculty affiliates from seven departments. The center will teach biologists, engineers, and others how to reach across the professional table by focusing their joint energies on biomechanics-the study of how organisms work and move in their natural habitats. In the process, both students and participating professionals will learn how to develop groundbreaking new designs in the spirit of Ariel, RHex, and RiSE.
Some institutions are meeting the need for modern interdisciplinary research by training students in many fields at once. But this approach, Full argues, produces a jack of all trades and master of none. Instead, CiBER encourages an integrative model in which students amass expertise in a single area but also learn how to contribute to and benefit from projects involving experts in other fields.
"When I collaborate with someone from a different discipline, I'm actually teaching them a sufficient amount of biology and they're teaching me enough math or engineering to know what's of value and how to interact with them," says Full.
The mutual effort can pay big dividends in each team member's field of expertise. For example, Full sought the assistance of Princeton University mathematician Philip Holmes to describe how animals stabilize their bodies in motion. Holmes realized the problem was new to mathematics, and wrote several papers on the topic. Full used Holmes' new mathematical model as the basis of several experiments that, in turn, inspired more discoveries in mathematics by Holmes. "These breakthroughs couldn't have been created without that interaction. So everybody accelerates their own field by this kind of mutually beneficial relationship and then everybody wins."
Companies, too, are now interested in interdisciplinary cooperation. To that end, CiBER offers businesses the chance to become corporate affiliates. The financial support these companies provide will be used to improve CiBER facilities and training opportunities. Meanwhile, students with ideas that hold promise for the market will gain exposure to industry. Industry partners have the potential to hire these students as interns or employees to enhance their research and product development capabilities.
"We want to shape students who, when they leave Berkeley, will form interdisciplinary collaborations naturally in their own research programs," Full says, citing several former students who are now university professors. "We now know how to create these incredible individuals for the future."
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Running, Swimming, and Flying for Science
The CiBER lab includes an impressive array of instruments to analyze animal motion and the properties of materials. Here, students record the movements of a running cockroach in high-speed video. Image courtesy of CiBER
The flight of the hummingbird is a thing of rare beauty. Its blur of wings and helicopter hovering are also marvels of natural engineering. Studying such high-performance acrobatics demands sophisticated instruments and equipment-devices more often found at Boeing than the confines of a university teaching lab.
But Berkeley is different.
Berkeley's Center for Integrative Biomechanics in Research and Education (CiBER) laboratory contains state-of-the-art equipment devoted to helping students, visiting scientists, and others discover the secrets of nature's designs.
Undergraduate and graduate biology and engineering students are already using the laboratory in an Integrative Biology course developed by CiBER director and Berkeley biology professor Robert Full plus fellow biologists and CiBER cofounders Mimi Koehl and Robert Dudley. The uncertain, investigative nature of the curriculum is designed to unleash a storm of collaborative creativity along the way.
CiBER co-director Mimi Koehl helps students use an instrument to test the resiliency of both chicken muscle and squid.Image courtesy of CiBER
"We want to stop treating students as file cabinets that we pour information into to be memorized. Instead, we want to act like research mentors and help them make personal and then universal discoveries," says Full. Full's approach is supported many studies indicating that participation in problem solving not only helps students retain information, but develops critical thinking and innovation.
The lab itself could be the site of an animal Olympiad. The various rooms and stations are fitted with high-speed cameras, bird-scale wind tunnels, a water flume resembling a tabletop endless pool, a miniature treadmill, and more. The assemblage is enough to support just about any current study of animal motion.
Traditionally, lab courses ask students to follow cookbook directions to obtain a predetermined result. Exercises in the CiBER lab are intentionally not so cut and dry.
For example, one lab asks students to run cockroaches over an obstacle course to observe how traveling over rough terrain alters the insects' neuromuscular signals. At first, the students observe none of the expected signal shifts. Most are taken aback by their results.
But by their second crack at the problem in a subsequent lab, many students will have taken matters into their own hands. Some will have researched the literature on cockroach biomechanics or discussed the problem with other students in the course. They learn that others have found results similar to their own and present the insects with higher and more challenging barriers.
"They approach original discovery here. And they've done it so often this semester that it's unprecedented for a teaching lab," Full says.
A CiBER lab student uses an enclosed miniature treadmill to measure the metabolic efficiency of a cockroachImage courtesy of CiBER
The uncertainty and additional research required to progress give students a taste of what working scientists do every day. The labs also foster close working relationships between engineers and biologists. For example, the materials testing station teaches students how to determine the stiffness or resiliency of a material. They start out by measuring the force required to stretch rubber tubing. The real challenge comes next: tugging a piece of chicken muscle. The biologists will dissect out and manipulate the tissue while taking into account the direction of the muscle fibers, and consider whether the muscle needs to be as warm and moist as it is inside the bird. The engineers, on the other hand, tend to take the lead in operating the control software and working out the mathematical calculations.
"Instead of each side being snobs about their expertise, they realize there's a lot to respect in each discipline," says Mimi Koehl. "It's not until they learn to communicate that the complexity of what we're dealing with comes through."
The semester closes with students pursuing independent research projects. "We work with them on what questions are worth asking to make a contribution to science, how to choose the organism that will best help answer your question, and how to propose and test a hypothesis," Koehl says.
The lab is already proving its mettle by eliminating the gap between teaching and research. This semester's students have broken new scientific ground in their lab research--work that Full and his colleagues will help shepherd to publication. In the process, the mysteries behind bird flight, squid propulsion, and insect sprinting will move ever closer to a scientific explanation. These discoveries will provide the biological inspiration to design the next generation of search-and-rescue robots, artificial muscles and new materials.
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Mother Nature's Engineering
Mimi Koehl has won many accolades for her research, including a MacArthur "genius" award in 1990. She is also the heroine of Nature's Machines, a children's book about her life and work. Image: courtesy Mimi Koehl
At the bottom of the ocean, a lobster follows its nose. In the dim vastness of the seafloor, the smell of prey is the most reliable guide to a good meal. But tracing a faint plume of scent to its source is no mean feat when currents are swirling odor molecules hither and yon.
The noses of lobsters are stick-like antennules bearing rows of odor-sensing hairs. To home in on prey, lobsters sniff by flicking their noses up and down like a fly fisherman working a stream. Berkeley professor of integrative biology Mimi Koehl sees the similarity between these "hairy little noses" and many other types of feathery and bristly structures.
Koehl used odor labeled with fluorescent dye and a laser to illuminate how lobster noses trap a scent molecules in turbulent water currents. Image: courtesy Mimi Koehl
Animals from crabs to fanworms, moths to barnacles also have appendages bristling with arrays of fine filaments. They sweep these combs or brushes through the air or water, or hold them up in the wind or waves to catch food or oxygen, or to meet a mate.
Koehl is studying how structures such as hairy limbs help organisms survive in a demanding environment. Gleaning design principles from living things is her stock in trade. Koehl is now working to disseminate this approach more broadly as a cofounder and instructor at CiBER, Berkeley's new Center for Interdisciplinary Bio-inspiration in Education and Research.
"I look across living things and ask, is there a kind of structure that gets used over and over again by different groups of organisms to do something important?" Koehl says. In this way, she can separate features that are species-specific from those critical to get the job done.
"For me, it's very important to observe organisms in their natural habitats and measure the aspects of their physical environment that impinge on them when they function," Koehl says. "If you really want to understand which aspects of an organism's structure affect its performance, you need to know what it does in nature."
Koehl studies organisms in natural habitats to better understand how their bodies interact with the environment. Here, she is examining how kelp on Tatoosh Island, Washington, withstand the crashing ocean waves. Image: courtesy Mimi Koehl
Using high-speed video, Koehl recorded live lobsters as they sniffed. With each flick of the antennule, the lobsters made an extremely rapid downstroke, followed by a much slower upstroke. But how did these movements affect the flow of water within the tuft of sensory nose hairs?
To find out, Koehl built a robotic lobster with a body made from the molted shell of a real lobster. Removing the nose antennules from lobsters bought at the fish market, she affixed them to robotic arms that would wave them up and down at a programmed pace. Koehl then put the robot downstream from an odor source in a big flow tank where she could mimic the turbulent water flow in a lobster's seafloor habitat. She labeled the odor with a fluorescent dye plume so she could see it, and turned out the lights. As the robo-lobster sniffed, she used a laser beam to illuminate just the paper-thin slice of water where the skinny antennule was flicking. Any dye molecules in the slice glowed, allowing Koehl to track the odor concentrations captured by the antennule with great precision.
She found that the rapid downstroke pushes old, stale water out from between the hairs as a new water sample enters. On the slower upstroke, this fresh sample remains trapped in the tuft of sensory filaments so the lobster can process the odor. Calculations of the fluid dynamics confirmed her findings.
Koehl is co-founder of Berkeley's new Center for Integrative Biomechanics in Research and Design, or CiBER. As part of a new CiBER lab course, she shows students how to measure water flow and turbulence in Strawberry Creek while assessing the hydrodynamic forces a crayfish would experience in the stream. Image: Simon Sponberg
"They're sniffing, just like we do. They're taking a discrete odor sample with each flick," Koehl says. "If you're trying to locate something, you want to know what it smells like now versus when you were someplace else."
By altering the dimensions, hair arrangement, and movements of her model, Koehl could observe how lobster noses performed against crabs, shrimps, and even the antennae on moths.
Her findings can help engineers develop sniffing robots that could be used to detect mines threatening harbors, sources of toxic waste, or other hazards.
"By understanding how nature's structures operate in messy real-world habitats, I provide design principles that can be used by people developing devices that must operate in complex environments," Koehl says. "We're using biological structures as inspiration for manmade designs."