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Washington State University develops two insect-like robots – a mini-bug and a water strider are the smallest, lightest, and fastest fully functional micro-robots ever created. These miniature robots could be used for artificial pollination, search and rescue, environmental monitoring, micro-fabrication, or robotic-assisted surgery.

According to Techxplore, the mini-bug weighs eight milligrams and the water strider weighs 55 milligrams, while both can move at about six millimeters per second. Conor Trygstad, a Ph.D. student in the School of Mechanical and Materials Engineering and lead author on the work explained that this movement speed is fast compared to other micro-robots at this scale, although it still lags behind their biological relatives. For comparison, an ant weighs up to five milligrams and can move at almost a meter per second.

The key to creating tiny robots is creating equally tiny actuators – Trygstad reportedly used a new fabrication technique to miniaturize the actuator down to less than a milligram, which is the smallest size ever known to have been made. The actuator uses a shape memory alloy that can change shapes when it’s heated, which “remembers” its original shape and returns to it. Furthermore, this tiny unconventional motor does not have any moving parts or spinning components.

These actuators are made of two tiny shape memory alloy wires that can be easily heated and cooled using a small amount of current, allowing the robots to flap their fins or move their feet up to 40 times per second.

Trygstad is an avid fly fisherman and has long observed water striders to study their movements. The researchers expressed their interest in copying another insect and developing a water strider-type robot that can move across the top of the water surface as well as just under it. They are also working on using tiny batteries or catalytic combustion to make their robots both fully autonomous and untethered from a power supply.