Machines and their makers battle at robot 'Olympics'

Robots from around the world will compete for supremacy in soccer, combat, sumo wrestling, and other arenas beginning Friday at a machine version of the Olympics in San Francisco.

Engineers from some two-dozen countries are pitting their creations against one another at RoboGames, deemed the planet's largest robot competition by Guinness World Records.

This year's RoboGames features 83 categories, 18 of them devoted to walking "android" robots designed in human forms.

A highlight of the event remains robot combat in which machines weighing as much as 340 pounds (154 kilograms) destroy one another in what amounts to a demolition derby behind bulletproof glass. The last robot still in operating condition wins.

Battle robots feature weapons such as saw blades, flamethrowers, and hydraulic hammers.