The Effects of Foot Trajectory on the Power Required to Swing a Mechanical Leg

The paper examines a two-degree-of-freedom serial-operated mechanical leg, driven by rotary actuators at hip and knee joints. When determining dynamic effects, three foot trajectories are compared: (a) ballistic, in which the foot is literally thrown from the end of the step to its start, (b) rectangular and (c) smoothed rectangular. In each case the conditions for minimum total energy are determined. In addition, when the trajectory is a smoothed rectangle, energies and powers for each actuator are calculated, and optimum conditions determined.