Let the battle of the machines begin again. Forty self-navigating robots were chosen on Monday to compete in the October 8 sequel to last year's first-ever robot race across the Mojave Desert.

Only half of the semi-finalists will qualify for a spot on the starting line, based on how they manoeuvre without human help through a series of obstacle courses.

The stakes are higher this time around: Organizers of the Pentagon-sponsored race doubled the prize money to US$2 million after none of the 15 contestants finished the rugged desert course last year.

A converted Hume by Carnegie Mellon University was the best performer last year despite travelling only 12 kilometres across the desert before breaking down. The team that designed the Humvee nicknamed Sandstorm is back for another shot with an improved version and is entering a second robot in the competition.

The semi-finalists will compete head-to-head at the California Speedway in Fontana in September and October in a series of trials designed to test their self-navigation skills. The robotic vehicles cannot be controlled remotely and must rely on global positioning satellites and various sensors, lasers, radar and cameras to orient themselves and detect and avoid barriers.

Based on the robots' performance, the field will be further whittled down and 20 robots will be chosen to race in October.

The first robot to make it across 240 kilometres of desert between Los Angeles and Las Vegas in less than 10 hours wins. The exact course will be revealed two hours before race time.

This year's semi-finalists include most of last year's participants vying for a second chance.

Source: China Daily