Locomotive and reptation motion induced by internal force and friction

TL;DR

This paper introduces simple mechanical models demonstrating how internal forces and friction can induce locomotive and reptation motions, including bipedal and snake-like movements, with potential applications to molecular motors.

Contribution

It presents novel mechanical models that show how internal forces combined with friction can produce directed locomotion and reptation, extending to chain and ladder structures.

Findings

Internal force alone does not produce motion without friction control.

Models exhibit bipedal motion similar to molecular motors.

Transition from straight to snake-like motion observed in ladder model.

Abstract

We propose a simple mechanical model of locomotion induced by internal force and friction. We first construct a system of two elements as an analog of the bipedal motion. The internal force does not induce a directional motion by itself because of the action-reaction law, but a directional motion becomes possible by the control of the frictional force. The efficiency of these model systems is studied using an analogy to the heat engine. As a modified version of the two-elements model, we construct a model which exhibits a bipedal motion similar to kinesin's motion of molecular motor. Next, we propose a linear chain model and a ladder model as an extension of the original two-element model,. We find a transition from a straight to a snake-like motion in a ladder model by changing the strength of the internal force.