Scientists in the US have created a tiny robot - as small as a speck - that they say could perform complex tasks, including repairing the circuit in computer chips.

The robot created by researchers at Dartmouth College, New Hampshire county, crawls like an inchworm caterpillar across a grid at the speed of 200 microns per second. Its goal: to fix really little things.

The robot is so small that 200 of them could fit on the tip of a finger and swarms of such devices could one day repair circuitry in computer chips, the online edition of Popular Science reported.

Unlike other miniature robots, which contain bulky motors, hinged joints, wheels and batteries, this robot, known as the Dartmouth 'bot, is little more than a sliver of flexible silicon, two bits of memory, and two actuators that convert electrical energy into motion, a researcher Bruce Donald quoted as saying.

Donald uses a computer to adjust electrical charges on the grid, thereby controlling its direction and speed.

When he increases the charge, an actuator on the machine's tail becomes oppositely charged and is thus attracted to the plate, causing the tail to flex and make contact with the grid's surface.

This pushes the shorter front leg 10 nanometers forward. At its fastest, the robot can take 20,000 steps a second. The next challenge is to assemble teams of robots to perform far more complex tasks, such as fixing a PC.