Energy Efficiency of Legged Robot Locomotion With Elastically-Suspended Loads Over a Range of Suspension Stiffnesses

Abstract

Elastically suspending a load from humans and animals can increase the energy efficiency of legged locomotion and load carrying. Similarly, elastically-suspended loads have the potential to increase the energy efficiency of legged robot locomotion. External loads and the inherent mass of a legged robot, such as batteries, electronics, and fuel, can be elastically-suspended from the robot chassis with a passive compliant suspension system, reducing the energetic cost of locomotion. In prior work, we developed a simple model to examine the effect of elastically-suspended loads on the energy cost of locomotion from first principles. In this paper, we present experimental results showing the energy cost of locomotion for a simple hexapod robot over a range of suspension stiffness values. Elastically-suspended loads were shown to reduce the energy cost of locomotion by up to 20% versus a rigidly-attached load. We compare the experimental results to the theoretical results predicted by the simple model.