Past walking robots have never tried including that nervous system feedback and the biological reflexes available to humans. The University of Arizona researchers built their robot with a neural controller - the half-centre - and leg sensors that are able to detect the weight of each step and report back to the neural controller.

The weight sensors join together with the robot's Kevlar straps that mimic leg muscles - another fairly unique aspect of the walking robot. Mechanical control comes from four motors in the hip segment, three motors in the thigh and just one motor in the calf.

Such baby steps for robot walking could lead to better understanding of how human babies and patients with spinal cord injuries learn to walk. But they could also improve bipedal humanoid robots that the U.S. military wants on tomorrow's battlefields, or that rescue workers could deploy in disaster zones.