Robust undulatory locomotion via neuromechanical adjustments in a dissipative medium

TL;DR

This paper models how neuromechanical adjustments enable robust undulatory locomotion in dissipative environments, inspired by C. elegans, using dynamical systems analysis to design adaptive behaviors and robotic applications.

Contribution

It introduces a mathematical model demonstrating how local neuromechanical adjustments produce stable, robust undulatory locomotion in dissipative media, with control of complex behaviors.

Findings

Local neuromechanical adjustments create stable locomotion.

Dynamical systems analysis reveals global stable periodic orbits.

Mechanosensation control enables maneuvering and complex behaviors.

Abstract

Dissipative environments are ubiquitous in nature, from microscopic swimmers in low-Reynolds-number fluids to macroscopic animals in frictional media. In this study, motivated by various behaviours of {\it Caenorhabditis elegans} during swimming and crawling locomotion, we consider a mathematical model of a slender elastic locomotor with an internal rhythmic neural pattern generator. By analysing the dynamical systems of the model using a Poincar\'e section, we found that local neuromechanical adjustments to the environment can create robust undulatory locomotion. This progressive behaviour emerges as a global stable periodic orbit in a broad range of parameter regions. Further, by controlling the mechanosensation, we were able to design the dynamical systems to manoeuvre with progressive, reverse, and turning motions as well as apparently random, complex behaviours, as experimentally observed in {\it C. elegans}. The mechanisms found in this study, together with our methodologies with the dynamical systems viewpoint, are useful for deciphering complex animal adaptive behaviours and also designing adaptive robots for a wide range of dissipative environments.