Clever leg

An artificial leg that mimics the way real legs move will let amputees walk
further over difficult terrain without getting tired, its developers say. The
prosthetic legs available today, such as the one worn by sprinter Ray Marlon
Shirley at this week’s Paralympics, are passive. For example, they
rely on inertia to bend and flex joints. These limbs need more energy input from
the wearer than normal walking. But researchers at Sandia National Laboratories
in Albuquerque, New Mexico, are building sensors into strategic parts of their
prosthesis and using hydraulically powered joints to control precisely how the
leg moves. The…