by Michael Cross
The trouble with most robots is that, although they can be designed to do a specific job very well, they are no good when confronted by a new task. Similarly, they find it difficult to deal with changes in terrain or working conditions.
Most engineers find it easier to design one robot for one job or terrain. All around the world, researchers are trying to create the all-purpose robot and are working on anything from tiny, bug-like devices to artificial biology.
Now, British inventor Joe Michael has come up with a simple concept that could be the key to robots that could build cars, explore Mars or bridge rivers after an earthquake. It's called the shape-changing robot.
His idea is, instead of building robots in a size and shape to do a particular job - handling nuclear fuel elements, for example - they should consist of many, smaller identical components... cubes. Each cube is equipped with motors, locking devices on surfaces and enough electronic processing power to attach to its neighbour when required, or to move along the neighbour's face. "A robot built of enough of these cubes could tackle almost any task," he explains.
Shape-changing robots would be comprised of cubes, some smaller and some bigger than others. On the right is a six-legged "walking machine" built of robotic cubes.
The design of the robot's basic building block is ingenious. Each cube is equipped with electromechanical locks and electrical contacts on each face. Each cube contains information processing circuitry storing its unique "address" and is able to move relative to its neighbours according to instructions from a master cube". Although some cubes might need specialist parts for example: a waterproof face - each would be essentially identical and redundant if it fails. When a rigid structure is needed, each cube could fasten itself firmly to its neighbour with retractable wedges. Each face has four wedges. A system of gears allows each cube to slide along the face of its neighbour when two of the wedges are retracted.
Upwards And Onwards
A walking machine built from these cubes might have six pairs of legs arranged along its body. To move forward, the cubes comprising the front pair of legs would slide upward to clear the ground, then forward along the body and then down again. The rear two pairs repeats the process and finally the body itself slides forward. Each cube must be able to receive power from any of its faces and direct it to any other. One cube acts as a master computer, holding and issuing control messages to robotic cubes.
"Apart from the master cube," says Mr Michael, "each building block would need only a modest computer on board a microcontroller with about the same complexity as a watch or a calculator chip. "The basic cube structure could be varied in many different ways. Some cubes might have 'fractal' faces, each capable of accommodating four smaller cubes. These in turn would be able to fit four smaller cubes on each face, and then four more down to the limits of nanotechnology. Such a robot could carry out highly precise tasks."
The design concept has already picked up a clutch of international awards at inventors' competitions from Monaco to Morocco to Pittsburg. The next stage is to build a working prototype. A team at the Open University, Britain's pioneering broadcast-based institute of further education, has taken up the challenge.
In the meantime, Joe Michael, who works as a computer programmer, is brimming with ideas for the invention. He envisages robots for manufacturing built from cubes between one and three centimetres in size.
"Production lines built out of such components could be self-repairing," he says. Another idea is to build giant structures from the basic frames, filling the cubes with ice when in place. Such structures could quickly create dams, warehouses and bridges for military purposes or to deal with natural disasters. Not a single area of human activity would not be affected by the use of the shape-changing robot.
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