Video: Silicone Robot Mimics Surroundings

Low-cost silicone robots that walk, change color to match their surroundings, and light up in the dark may soon be added to the array of robots (discussed here and elsewhere) that are helping first responders and the military.

Researchers at Harvard University's department of chemistry and chemical biology and its Wyss Institute for Biologically Inspired Engineering have developed the latest robot under DARPA's Maximum Mobility and Manipulation (M3) program.

The soft, vaguely starfish-shaped robot is equipped with microfluidic channels. The networks of these channels are contained in thin silicone sheets, called color layers. Air and other fluids (such as water, heated or cooled dye, and fluorescent or chemiluminescent solutions) are pumped through the color layers. Depending on the combination, they can change the robot's surface temperature, color, luminescence, and shape, letting it blend with its environment. Alternatively, the robot can glow with the help of chemiluminescence or fluorescent fluids.

The robot's movement is controlled by pneumatically pressurizing and inflating the channels. When filled with fluid, it moves at approximately 40 meters per hour. Without the fluid, the speed rises to about 67 meters per hour. Though future research will focus on smoothing its movements to improve the speed, the researchers say the robot's flexibility is more important.

DARPA is interested in soft robots because they are flexible and resilient and can change their shape to maneuver through tight spaces. In the video below, the researchers demonstrate the robot's abilities using tethers that are attached to the control system and pump pressurized gases and liquids into the robot.

Though future versions may incorporate power sources and pumps in the robot itself, operating it with tethers reduces its size and weight. The current rate of pumping (2.25ml per minute), produces a color change in the robot after 30 seconds. After the color layers are filled, they can sustain their color without additional power.

The shapes are made with molds produced with a 3D printer and cost less than $100 each. To date, developing robotics technologies that can be used for Department of Defense applications hasn't been cheap. DARPA says the soft robots' low cost helps overcome one of the major obstacles to DoD adoption of robot technology.

Last year, some of the same researchers developed the first soft silicone robots, modeling them after cephalopods such as squid, which produce instantly changeable camouflage patterns and communicate with colored inks and bioluminescence. In search-and-rescue operations, the new robot could fluoresce to stand out in a dark corridor and guide first responders to injured people.

The robot may also have medical applications. They could be incorporated into prosthetics technology, for example, and the ability to simulate blood vessels and muscle motion may help doctors plan surgeries.

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