Meeting Abstract

16 A-5   11:00 - 11:15  Gait transitions in centipede locomotion on complex terrains Erickson, E*; Diaz, K; Wang, T; Chong, B; He, J; Goldman, DI; Georgia Institute of Technology; Georgia Institute of Technology; Georgia Institute of Technology; Georgia Institute of Technology; Georgia Institute of Technology; Georgia Institute of Technology eerickson31@gatech.edu

Centipedes can generate motion in diverse environments via propagation of coordinated travelling waves of body and limb flexion. However, understanding how these animals coordinate their many degrees of freedom to traverse complex terrains remains a challenge. To study the body-limb coordination of centipedes on complex terrains, we challenged Scolopocryptops sexspinosus (N=6, L =10.18±1.85 mm, 21 joints and leg pairs) to traverse a flat surface and Gaussian-distributed rough terrains (12 x 24 cm² with variable height of blocks ranging from 0 to 12 mm). On flat terrain, the centipedes generated motion by propagating a limb-stepping pattern in the direction of motion (direct waves) with a speed of 0.93±0.21 body lengths per gait cycle (BL/cyc). Surprisingly, on the rough terrain, the centipedes would change the direction of propagation of the limb-stepping pattern opposite to the direction of motion (retrograde waves) with speeds of 0.79±0.14 BL/cyc. We posit retrograde waves allow the centipedes to guarantee limb-substrate contact to traverse complex terrain. Furthermore, when legs made contact with obstacles, instead of jamming, their limbs passively glided against the blocks allowing them to continue their path with minimal perturbation of the body-limb coordination. This suggests that these animals are using a combination of both active and passive mechanisms to negotiate and navigate complex terrains.