Two insect-like robots, a mini-bug and a water strider, developed at Washington State University, are the smallest, lightest and fastest fully functional micro-robots ever known to be created.
Such miniature robots could someday be used for work in areas resembling artificial pollination, search and rescue, environmental monitoring, micro-fabrication or robotic-assisted surgery. Reporting on their work within the proceedings of the IEEE Robotics and Automation Society’s International Conference on Intelligent Robots and Systems, the mini-bug weighs in at eight milligrams while the water strider weighs 55 milligrams. Each can move at about six millimeters a second.
“That’s fast in comparison with other micro-robots at this scale even though it still lags behind their biological relatives,” said Conor Trygstad, a PhD student within the School of Mechanical and Materials Engineering and lead creator on the work. An ant typically weighs as much as five milligrams and might move at almost a meter per second.
The important thing to the tiny robots is their tiny actuators that make the robots move. Trygstad used a brand new fabrication technique to miniaturize the actuator right down to lower than a milligram, the smallest ever known to have been made.
“The actuators are the smallest and fastest ever developed for micro-robotics,” said Néstor O. Pérez-Arancibia, Flaherty Associate Professor in Engineering at WSU’s School of Mechanical and Materials Engineering who led the project.
The actuator uses a fabric called a shape memory alloy that’s capable of change shapes when it’s heated. It known as ‘shape memory’ since it remembers after which returns to its original shape. Unlike a typical motor that will move a robot, these alloys have no moving parts or spinning components.
“They’re very mechanically sound,” said Trygstad. “The event of the very lightweight actuator opens up recent realms in micro-robotics.”
Shape memory alloys should not generally used for large-scale robotic movement because they’re too slow. Within the case of the WSU robots, nonetheless, the actuators are fabricated from two tiny shape memory alloy wires which can be 1/1000 of an inch in diameter. With a small amount of current, the wires may be heated up and cooled easily, allowing the robots to flap their fins or move their feet at as much as 40 times per second. In preliminary tests, the actuator was also capable of lift greater than 150 times its own weight.
In comparison with other technologies used to make robots move, the SMA technology also requires only a really small amount of electricity or heat to make them move.
“The SMA system requires rather a lot less sophisticated systems to power them,” said Trygstad.
Trygstad, an avid fly fisherman, has long observed water striders and would really like to further study their movements. While the WSU water strider robot does a flat flapping motion to maneuver itself, the natural insect does a more efficient rowing motion with its legs, which is certainly one of the explanations that the true thing can move much faster.
The researchers would really like to repeat one other insect and develop a water strider-type robot that may move across the highest of the water surface in addition to slightly below it. Also they are working to make use of tiny batteries or catalytic combustion to make their robots fully autonomous and untethered from an influence supply.
