MIT engineers develop flexible, 'plant-like' robot

In a move to expand the role robotics play in today's factories and warehouses, engineers at MIT have developed a flexible but sturdy robot that can meander through tight spaces and lift heavy objects, the institution said this week.

Inspired by the way a plant grows, the robot is designed with a chain-like appendage that extends and can twist and turn in any configuration to access hard-to-reach places. It is also rigid enough to support heavy loads or apply torque to assemble parts, according to MIT. Presented during the recent IEEE International Conference on Intelligent Robots and Systems (IROS), the robot represents a leap beyond today's robots that can easily navigate across open laoyouts but have a harder time with fine-tuned tasks that require bending and reaching around items and equipment, the researchers say.

"Think about changing the oil in your car," Harry Asada, professor of mechanical engineering at MIT, said in a statement. "After you open the engine roof, you have to be flexible enough to make sharp turns, left and right, to get to the oil filter, and then you have to be strong enough to twist the oil filter cap to remove it."

"Now we have a robot that can potentially accomplish such tasks," added Tongxi Yan, a former graduate student in Asada's lab, who led the work on the new robotic solution. "It can grow, retract, and grow again to a different shape, to adapt to its environment."

The design mirrors the way plants grow, "which involves the transport of nutrients, in a fluidized form, up to the plant's tip. There, they [nutrients] are converted into solid material to produce, bit by bit, a supportive stem," according to MIT. In a similar way, the flexible robot's "growing point" is a gearbox that pulls a loose chain of interlocking blocks into the box. Gears in the box then lock the chain units together and feed the chain out, unit by unit, as a rigid appendage.

The design of the new robot is an offshoot of Asada's work to address the  "last one-foot problem"—an engineering term referring to the last step, or foot, of a robot's task or exploratory mission. Robots spend much of their time navigating open space—moving items from one place to another, for example—but the last foot of their mission may require "more nimble navigation through tighter, more complex spaces to complete a task," according to the researchers. 

MIT's new flexible robot can help accomplish those goals. By adding grippers, cameras, and sensors mounted on the gearbox, the researchers say the robot could potentially meander through an aircraft's propulsion system and tighten a loose screw or reach into a cabinet to grasp a product without disturbing the inventory around it. Auto maintenance is another example of a potential application.

"The space under the hood is relatively open, but it's that last bit where you have to navigate around an engine block or something to get to the oil filter, that a fixed arm wouldn't be able to navigate around," according to MIT graduate student Emily Kamienski, who also worked on the project. "This robot could do something like that."