Robots that walk on water

Earlier a   robot made of ultralight carbon-fiber can stand or slowly walk on water. The principle it uses is borrowed from insects -- surface tension tends to prevent the water's surface from breaking, and the robot's legs from sinking in.

 Recently  the first bio-inspired microbot is capable of not just walking on water but jumping up and down on the water's surface like the insect, a study shows.

Qinmin Pan and colleagues from Harbin Institute of Technology and the National Natural Science Foundation of China, reported a number of advances toward tiny robots that can walk on water.

However, even the most advanced designs, including one from Pan's team last year - can only walk on water. Pan noted that real water striders actually leap, the journal Applied Materials & Interfaces reported.

Pan's group looked for novel mechanisms and materials to build a true water-striding robot, according to a Harbin Institute statement. The weight of the microrobot is equal to that of about 390 water striders, one might expect that it will sink quickly when placed on the water surface," the report noted. Instead, the mechanical creature stands effortlessly on water surfaces and also walks and turns freely

Making a jumping robot is difficult because the downward force needed to propel it into the air usually pushes the legs through the water's surface.

Using porous, super water-repellant nickel foam to fabricate the three supporting and two jumping legs, the group made a robot that could leap more than 5.5 inches, despite weighing as much as 1,100 water striders.

In experiments, the robot could jump nearly 14 inches forward -- more than twice its own length -- leaving the water at about 3.6 miles per hour.

The study authors report that the ability to leap will make the bio-inspired microrobot more agile and better able to avoid obstacles it encounters on the water's surface

Credit:American chemical society NEWS