Bipedal robot (image 3 of 3). Bipedal robot walking down a slope. This gravity-powered walker may help to improve prosthetic legs and walking robots. The robot models the role of mechanics in two-dimensional human walking. It can move despite having no control system. This shows the importance of gravity, inertia and ground contact in walking. Traditionally, more emphasis has been placed on nervous control. The walker is a near duplicate of one designed by the Canadian engineer and roboticist Tad McGeer. Photographed at the Human Power, Biomechanics and Robotics Laboratory at Cornell University, USA. For a sequence of the robot walking see images T280/085-087.