87-4 Monday, Jan. 6 10:45 - 11:00 Template model reveals mechanism of wing and leg coordination during self-righting of a cockroach-inspired robot XUAN, Q*; LI, C; Johns Hopkins University; Johns Hopkins University email@example.com
Self-righting is a critical ability that terrestrial animals must have to survive. The discoid cockroach can push its wings against the ground to somersault and dynamically self-right. However, because this maneuver is strenuous, the animal often cannot build up sufficient kinetic energy to overcome the large potential energy barrier required to pitch the body. In this case, the animal often flails its legs, which adds kinetic energy to help overcome the barrier by body rolling. Our recent study using a cockroach-inspired robot showed that self-righting requires good coordination (good phases) between wing pushing and leg flailing. Here, we further understand the mechanism of phase dependence by developing a template model. Our planar template model rotates in the sagittal plane and has two massless wings and a flailing leg with mass at its end. Applying the similar geometry size, mass distribution, and actuation profile, the model also struggled to self-right and relied on a good coordination of body parts. We first validated the model against a multi-body dynamics simulation. Then, we used the template model to calculate mechanical energy injection by the wings and leg, mechanical energy dissipation due to collision and friction, and potential energy barrier. Our model revealed that, although phase affected energy injection and dissipation in complex ways, good phases resulted in mechanical energy accumulation that exceeded the potential energy barrier, whereas bad phases did not do so. Our study elucidated the mechanism of coordination between thrusting and perturbing appendages to cumulate energy to overcome the barrier during strenuous maneuvers such as self-righting.