Robots Start To Evolve

LIVING creatures took millions of years to evolve from amphibians to four-legged mammals - with larger, more complex brains to match. Now an evolving robot has performed a similar trick in hours, thanks to a software ‘brain’ that automatically grows in size and complexity as its physical body develops. Existing robots cannot usually cope with physical changes - the addition of a sensor or new type of limb, say - without a complete redesign of their control software, which can be time-consuming and expensive. As animals evolved, additions of small groups of neurons on top of existing neural structures are thought to have allowed their brain complexity to increase steadily, keeping pace with the development of new limbs and senses. In the same way, robot's brain assigns new clusters of "neurons" to adapt to new additions to its body. The robot is controlled by a neural network - software that mimics the brain's learning process. This comprises a set of interconnected processing nodes which can be trained to produce desired actions.

For example, if the goal is to remain balanced and the robot receives inputs from sensors that it is tipping over, it will move its limbs in an attempt to right itself. Such actions are shaped by adjusting the importance, or weighting, of the input signals to each node. Certain combinations of these sensor inputs cause the node to fire a signal - to drive a motor, for example. If this action works, the combination is kept. If it fails, and the robot falls over, the robot will make adjustments and try something different next time. Finding the best combinations is not easy - so roboticists often use an evolutionary algorithm to ‘evolve’ the optimal control system. The application randomly creates large numbers of control ‘genomes’ for the robot. These behaviour patterns are tested in training sessions, and the most successful genomes are ‘bred’ together to create still better versions - until the best control system is arrived at. The robot can also adapt to newly acquired vision, and learn how to avoid or seek light when given a camera.

More information:

http://www.newscientist.com/article/mg20126946.600-unnatural-selection-robots-are-starting-to-evolve.html