Footprints in the Asphalt

This paper describes our experiences with a man-carrying, 1600-lb, gasoline-powered, hydraulically actuated, six-legged walking machine. An on-board computer uses leg position and loading information to select one of a few possible hy draulic connections of the leg actuators by switching direc tional control valves. Passive parallel connections of hydraulic actuators distribute loads equally among several legs, creat ing the effect of a smaller number of "virtual legs. " Series connections of hydraulic actuators achieve coordinated leg motions during walking. The machine uses no sophisticated servos.