Energy Efficiency of Legged Robot Locomotion With Elastically Suspended Loads

Elasticity is an essential property of legged locomotion. Elastically suspending a load can increase the efficiency of locomotion and load carrying in biological systems and for human applications. 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, motors, and fuel, can be elastically suspended from the robot with compliant springs, passively reducing the energetic cost of locomotion. An experimental elastic load suspension mechanism was developed and utilized on a hexapod robot to test the energetic cost of legged robot locomotion over a range of suspension stiffness values. While running at the same speed, the robot with an elastically suspended load consumed up to 24% less power than with a rigidly attached load. Thus, elastically suspended loads could increase the operation time, load-carrying capacity, or top speed of legged robots, enhancing their utility in many roles.