Collision-induced scattering of a self-propelled slithering robot
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Collisions with environmental heterogeneities are ubiquitous in living and artificial self-propelled systems. The driven and damped dynamics of such "active" collisions are fundamentally different from momentum-conserving interactions studied in classical physics. Here we treat such interactions in a scattering framework, studying a sensory-deprived snake-like robot whose lateral undulation scheme typifies a important class of self-propelled systems. During transit through a regular array of posts, interactions between the posts and robot segments reorient the heading, producing scattering patterns reminiscent of those in matter-wave diffraction. As spacing decreases, the robot scatters more strongly; for small inter-post spacing, scattering occurs in preferred directions. Active scattering dynamics are dominated by collisions of the head with a single post; scattering angle correlates with collision duration which in turn is governed by incident undulation phase and post impact location. A model which incorporates these observations reveals that the spacing dependence arises from a remapping of single-post collision states. Our results could lead to simple control schemes for snake-like robots, useful in search and rescue in cluttered environments.
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