Walking Gait, Energy Efficiency, and Energy Harvesting of a Simple Biped Robot

Abstract To design energy efficient robots, researchers have dedicated themselves to examining the locomotion dynamics and walking pattern generation of passive bipeds. As the walking environment or system parameter changes, an energy use efficient robot may become inefficient, a possible approach to increase the energy efficiency is through the ability to harvest the energy used during the locomotion. The goal of the paper is to investigate the relations of a biped’s walking speed, locomotion energy consumption, as well as the ability to retrieve the lost energy as system parameter varying. Piezoelectric bimorphs were attached to the feet of the biped to harvest energy via exploiting the acceleration excitations induced vibrations at the instant foot lift and heel strike. As the incline angle of the ramp slope increases, the stable periodic-1 (P1) walking gait becomes faster and more energy costing. Also means more available energy to harvest, although the retrieved energy is much smaller compared to the locomotive energy. As the slope angle continues growth, the stable walking experiences sequence of period doubling (PD) bifurcations, becomes P2, P4, P8, and Chaos walking. As the walking gaits change, the walking speed, locomotion energy consumption, as well as the harvested energy grows as the slope becomes deeper.