Adjusting step length for rough terrain locomotion

The task of controlling step length in the context of a dynamic biped robot that actively balances itself as it runs is discussed. Three methods for controlling step length, each of which adjusts a different parameter of the running cycle, are discussed. The adjusted parameters are forward running speed, running height, and duration of ground contact. All three control methods are successful in manipulating step length in laboratory experiments, but the method that adjusted forward speed provided the widest range of step lengths with accurate control of step length. The three methods for controlling step length manipulated the dynamics of the system so the feet could be placed on the available footholds without disturbing the system's balance. An alternative approach which ignores balance for a single step, placing the foot directly on the desired foothold, and recovering balance later is described. >