Every robot has its limit.
For the famous Roomba vacuum, it's two to three hours. For the several thousand robots deployed in Iraq, about the same. For the warehouse robots sorting our sneaker orders, eight hours. And the Energizer Bunny? Forget about it -- a few minutes, tops.
Perhaps more than any other factor, the life span of batteries has limited the infiltration of robotics into daily life. As computer processing and sensors have become cheaper and more powerful by the year, batteries, woefully inefficient and slow to recharge, have slogged behind, leaving engineers to dream of a day when they'll have the juice to give life to their boldest creations.
And so roboticists have watched the huge increase in investment into battery technology this year, driven by the new administration in Washington and the push for electric cars, with much interest. This month alone, the Energy Department announced $2.4 billion in battery-related funding.
While the majority of this funding will manifest first in the garage, it will likely allow robotics to push into entirely new, mobile realms, according to Henrik Christensen, the director of the Center for Robotics and Intelligent Machines at the Georgia Institute of Technology.
"We are going to piggyback on whatever they're going to do," he said. "We're never going to be big enough to drive the market alone.
"There is no doubt that new development in robot technology is very much going to benefit from battery technology," he added.
Indeed, for engineers designing robots that operate not tethered to electrical outlets, the field is in a bit of a rut, said Dennis Hong, director of the Robotics and Mechanisms Lab at Virginia Tech.
"We're currently at a design threshold right now," Hong said. "We can't add more batteries, then it becomes heavier. But if it's lighter, [the robot] lasts only 10 minutes."
Perhaps the greatest implication of improved batteries will be in autonomous robots -- machines that not only operate independently but are also able to make judgments and, in effect, think and learn. For purists, these are the only proper robots. The mechanical arms that have long been a mainstay of manufacturing are merely complex tools in comparison.
For decades, most robotics have remained partitioned behind virtual or actual fences, mostly out of the fear that they could accidentally trample or harm humans. Given incipient awareness and long-lasting batteries, robots could now break these barriers, mingling with humans at the job, on the road and in the home.
Such robots are closer than we think, Hong said. At his lab, they have already designed prototype cars that drive themselves, and work is under way on a small, humanoid robot that will give tours of the school campus.
"The technology will be ready before society is ready," he said.
Some autonomous robots are already in use today as factories and warehouses have begun employing the machines to move materials with little human guidance. Christensen's lab is collaborating with Boeing on robots to move its cumbersome, heavy aircraft pieces. And a high-tech start-up, Kiva Systems, has designed an entirely different take on the modern warehouse that uses self-coordinating robots as "movable shelves."
Kiva's robots run low on charge after eight hours, after which they automatically return to charging stations. Longer lasting batteries would allow their warehouse systems -- which have been adopted by high-profile clients like Zappos, an online retailer -- to use fewer robots, lowering costs, said Mitch Rosenberg, Kiva's spokesman.