Biologically inspired robot can walk, run, climb walls, and more
With six legs and a host of flashing lights, a robot claws its way up a carpeted wall.
This robot is RiSE, the second prototype in the Robots in Scansorial Environments project. RiSE is the product of collaboration between 20 researchers across seven different research groups. The schools involved include the University of Pennsylvania, Stanford, Berkeley, Lewis and Clark University, and our own Carnegie Mellon.
Engineers, computer scientists, and biologists from these schools are joined by industrial affiliates from Boston Dynamics, Inc. The resulting project is a five-year, $10 million DARPA-funded experiment in biodynotics, or the development of robots inspired by biology.
The biological inspirations for RiSE are some simple animals with amazing climbing abilities. Professor Al Rizzi heads the RiSE group at Carnegie Mellon, and described the project?s inspirations as ?cockroaches and spiders and geckos.? The robot?s ties to nature are evident in its six legs and fluid climbing style. As it ascends the wall, it?s easily mistaken for a large, robotic spider.
Nevertheless, Rizzi is quick to point out that though RiSE is inspired by biology, it does not mimic it. ?The key thing is, we?re not doing biomimetics,? noted Rizzi. ?We?re doing biologically inspired design. Biomimetics brings up this notion that what you will do is you?ll look at biology and you?ll try to copy biology. There are a lot of reasons that?s really hard to do.?
Instead, RiSE focuses on the core concepts behind animal behaviors. Rizzi explained, ?What we try to do with our biologist colleagues is to try to recognize what are key principles that the animals exhibit.... We try and tease out the most basic components of that.? This distinction is the driving force behind DARPA?s new biodynotics program, which funds several projects including RiSE.
At first glance, it?s hard to imagine that RiSE is adept at climbing. According to Rizzi, its body measures only 25 centimeters and weighs just three kilograms. RiSE has six short, fairly complex legs that jut out from its black chassis. Each leg has a set of mechanical parts, allowing the leg to move with six degrees of freedom, like human arms.
Controlling and powering these legs requires a mesh of computer chips and wires ? RiSE?s brain, heart, and arteries. Exposed, the innards look commonplace, like the components in any computer.
However, that?s where the comparisons end. RiSE is clearly built for climbing ? and climbing quickly ? with springs in its legs and claws on its feet. RiSE even has a tail. ?Tails are very important for climbing, so you don?t fall over backwards,? Rizzi
This is not the first biologically inspired project for Rizzi and his team. An earlier project called RHex relied heavily on cockroach physiology to construct a robot that could navigate uneven horizontal surfaces. The key concept, Rizzi said, is putting a bounce in RHex?s step: ?[They] have well-defined springs in their legs that make it possible for them to run quickly, to go straight over very rough terrain.?
The success of the RHex led Rizzi and his collaborators to begin the RiSE project. Using similar ideals, the project goal was to create a robot that runs like RHex but can climb sheer walls.
Every aspect of RiSE is engineered for difficult climbs. While its legs use the same spring technology that powered RHex?s bouncy walk, RiSE employs them for an additional purpose. RiSE uses the springs to ?pull one foot against the other, to grip,? said Rizzi.
In nature, this gripping motion is seen in cats, squirrels, and geckos.
Rizzi explained that RiSE also uses these simple springs as ?shock absorbers? to walk across rough terrain.
RiSE has other climbing tools at its disposal, including a drawer full of specially engineered feet. There are several varieties of these, including feet with claws and feet smothered in an adhesive substance. Rizzi explained that each foot serves a different purpose and gives RiSE the ability to climb on materials ranging from Plexiglass to wood and on shapes varying from smooth panels to trees.
Clark Haynes, a graduate student on the project, offered a demonstration of RiSE?s capabilities. The feet installed on RiSE for its climb were sharp, curved claws called ?dactyl? feet, similar to cat claws. ?These ?dactyl? feet ? they?re just hardened wire ? we use these for climbing on carpeted surfaces and trees,? Haynes explained.
Haynes placed RiSE on a carpeted wall and demonstrated a ?pentapod? gait, which keeps five feet firmly planted and only one in the air. The result was a stable, insect-style climb up a stretch of wall many times the length of RiSE itself. RiSE demonstrated its agility by moving up, down, and turning 90 degrees to move perpendicular to the floor.
RiSE has complex behaviors to support its climbing. For example, ?the robot actually paws like a cat would? to secure a better hold on surfaces, Haynes said. ?It?s really fun to watch.?
As a multidisciplinary project, Robots in Scansorial Environments requires a lot of
coordination. Rizzi described communication as time consuming. ?Seven research groups trying to make coherent progress takes a lot of effort by each one,? he said. ?My group, each of us spends an hour and a half, two hours a week in teleconferences.?
The project also requires significant long-term planning. ?It takes us a year, year and a half to get around that cycle,? Rizzi said.
But this collaboration between biologists, biomechanicists, computer scientists, and engineers yields impressive results. Their previous robot, RHex, proved a simple but nimble runner. Now, RiSE has taken to both the wall and the frontiers of robotics. ?You have to be a little bit committed to that multidisciplinary approach to make it pay off,? Rizzi said. And has it? ?It has paid off very well,? he said.
As for immediate concerns, Rizzi said, ?we need a machine that?s stronger, faster, lighter ? [a machine] that is Superman.?
Apparently, the RiSE team has already surpassed Spider-Man.