Meeting Abstract
Analogous to how aerodynamic shapes and control surfaces help modulate forces during flight, recent studies demonstrated that body shape plays an important role in terrestrial locomotion in complex 3-D terrains. When encountering pillar obstacles, the discoid cockroach with an elliptical body shape often turned away from pillars (92 ± 4%) and traversed (81 ± 6%). By contrast, with a cuboidal body shape, the animal often turned towards and pitched up against pillars (86 ± 5%), but often eventually traversed (41 ± 8%). Here, to begin to understand whether passive body-terrain interaction is sufficient for traversing complex 3-D terrains or traversal requires sensory feedback, we tested a legged robot with no sensing capability and compared its locomotion with that of the animal. With an elliptical body, the feedforward robot almost always turned away from the pillar (98 ± 2%) and traversed. With a cuboidal body, although the feedforward robot usually turned towards the pillar (96 ± 2%), unlike the animal which often traversed, the robot almost never traversed (2 ± 1%), but was instead trapped pitching up against the pillar and eventually flipped over (98 ± 2%). This distinct difference suggested that, although the passive body-terrain interaction affected movement during the initial phase of obstacle negotiation, the animal likely used active sensory feedback to overcome it in order to traverse. To begin to study this, we impaired sensory feedback of the animal by cutting off its antennae. We found that the animal without antennae was more likely to flip over (43 ± 27%) than with antennae (6 ± 4%; P < 0.0001, ANOVA), and thus traversed less often. Our study provides inspiration for robot to integrate sensory feedback with terradynamic shapes to better traverse complex 3-D terrains.
