Many robotics groups around the globe are trying to make androids, but a robot biped for industry is a new twist. "Everybody loves the idea of a droid," says project leader Joe Cronin of the University of New South Wales in Sydney.

"But we think our robot has a better chance of being commercially viable. The great difference is that humanoids will one day do what humans can do. But our industrial bipeds will be able to do what humans can't do," added Cronin.

The Robolift stands 3 metres tall and will be able to lift a load of 500 kilograms when it is fitted with arms. Its power comes from a propane-fuelled 20 horsepower engine--the team decided against weak, quickly depleted batteries.

At a symposium on Computational Intelligence in Robotics in Monterey, California, last week, Cronin described how Robolift balanced successfully in their tests, a critical milestone before taking its first steps. Robolift balances much like a person, using a combination of standard movements of its leg and foot joints as well as more drastic hip movements, if necessary.

When standing still, the robot should have equal pressure on each foot. If the robot is pushed, sensors in the legs and feet detect it and move the joints to compensate, if possible.

If not, then a larger movement is triggered at the hips, just like a person trying to balance on one foot. A gyroscope tells the robot when it has moved enough to stop falling.

Once it has arms it will use a similar technique to balance while lifting: a payload will trigger the same response as a push on the robot's back.

Ultimately, the robot will be controlled by an on-board operator, but for now a tethered joystick is used. Either way, a built-in computer translates the operator's commands into the movements needed at each joint.

If a joint cannot move because of a change in terrain, say, it tells the computer, and the robot makes a drastic hip movement to regain control before it tries to take a step.

According to Cronin, balancing was the greatest hurdle in Robolift's development. "We'll have it walking by the end of the year," he says. After that the final step will be to add arms, either like those on a forklift or some type of grasper reminiscent of the machine in Aliens, he says.

Robert Howe, an engineer who works with two-legged robots at Harvard University in Massachusetts, is enthusiastic about the Australians' work. "I'd wager they're going to get it walking," he says. "It's an original idea."

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