Meeting Abstract

P3.155  Monday, Jan. 6 15:30  Construction of a mudskipper-inspired robot to study crutching locomotion on flowable ground MCINROE, B.M.*; GOLDMAN, D.I.; Georgia Institute of Technology; Georgia Institute of Technology bmcinroe3@gatech.edu

Throughout history, many organisms have used flipper-like limbs for both aquatic and terrestrial locomotion. Modern examples include mudskippers (Oxudercinae) and sea turtles (Chelonioidea); extinct examples include walkers such as the early tetrapods Tiktaalik and Ichthyostega. In the transition from an aquatic to a terrestrial environment, early walkers would have had to adapt to the challenges of locomotion over flowable media like sand and mud. While the limb-joint morphology of Ichthyostega has been recently described, and it has been hypothesized that its mechanism of locomotion may have been similar to the symmetric gait of a mudskipper [Pierce et. al. 2012], the relationship between form and function in flowable environments has not yet been elucidated. Previously, we discovered that a flipper with a wrist which could passively flex and extend toward and away from the body improved the performance of a sea turtle-inspired robot crawling on dry granular media [Mazouchova et. al. 2013], a result related to the jamming of material behind and beneath the flipper. To gain insight into how an additional degree of freedom of the wrist affects flipper-based locomotors, we have built a robotic model with limb-joint morphology inspired by the reconstruction of Pierce et. al. We add to our previous limb design a passive degree of freedom that allows for up-down flexion and extension of the flipper about a variable insertion angle. Springs at the joints restore the flippers to equilibrium positions after interaction with the media. We study the crutching locomotion of the robot performing a symmetric gait, varying limb cycle frequency and insertion angle.