0
Facebook
Volume 89 Issue 49 | p. 36 | Concentrates
Issue Date: December 5, 2011

Soft Robot Walks

Harvard scientists create floppy, all-polymer crawler capable of navigating obstacles
Department: Science & Technology
News Channels: Materials SCENE, Nano SCENE
Keywords: robotics, soft robots, elastomeric polymers, materials science
Wiggling its limbs and spine, an all-polymer robot moves forward about half an inch in one step; the inset shows which limbs are pressurized (green) and which ones are not (red) during the cycle.
Credit: Proc. Natl. Acad. Sci. USA
Researchers at Harvard have fabricated a soft robot entirely from elastomeric polymers. The robot is propelled by a pneumatic actuator (in other words, air pressure) and can be programmed to have a number of gait. In this figure, an undulating gait is shown, in which air pockets in the robot’s arms and spine are pressurized and depressurized in turn.
 
Wiggling its limbs and spine, an all-polymer robot moves forward about half an inch in one step; the inset shows which limbs are pressurized (green) and which ones are not (red) during the cycle.
Credit: Proc. Natl. Acad. Sci. USA
In this clip, a starfish-inspired robot, made from elastomeric polymers, crawls, undulates, and creeps under an obstacle.
Credit: Proc. Natl. Acad. Sci. USA/C&EN

Not all robots must contain heavy metal skeletons and parts such as mechanical joints, according to a research team at Harvard University. Led by George M. Whitesides, the scientists have constructed an all-polymer robot that can crawl and undulate backward and forward, even navigating obstacles (Proc. Natl. Acad. Sci. USA, DOI: 10.1073/pnas.1116564108). Fabricated with soft-lithography techniques used to build microfluidic devices, the robot moves via a series of inflatable chambers embedded between layers of the stretchy commercial elastomer Ecoflex and the more rigid plastic polydimethylsiloxane (C&EN, Feb. 14, page 36). The researchers sequentially inflate the chambers in the arms and spine of the tetrapod robot to propel it along. Because of its flexibility, the 0.9-cm-thick robot is able to pass below a glass plate elevated only 2 cm from a surface. The soft crawler has a number of favorable qualities, including its simple, lightweight design, the researchers say. But other materials will be needed to improve its durability and load-bearing capacity. “Soft robotics,” they write, “may, thus, initially be a field more closely related to materials science and to chemistry than to mechanical engineering.”

 
Chemical & Engineering News
ISSN 0009-2347
Copyright © American Chemical Society