Correlating kinetics and kinematics of earthworm peristaltic locomotion

Abstract

The study of biological organisms may aid with designing more dynamic, adaptable robots. In this paper, we quantitatively studied the coupling of kinematics and kinetics in the common earthworm, Lumbricus terrestris. Our data correlates changes in worm segment shape to variable, non-uniform load distribution of worm weight. This presumably leads to variable friction forces. Understanding the way the worm exerts these forces may help us implement peristalsis in robots in diverse real-world environments. In our preliminary data, at the front of the worm, the segments with the widest diameter bear the most weight and anchor the worm to the ground during motion, as we hypothesized. The rear segments also exhibit variation in ground reaction forces. However, for rear segments, the peak kinetic waves are phase-shifted from the kinematic waves. Future work will explore this phenomenon.