On break-away forces in actuated motion systems with nonlinear friction

TL;DR

This paper analyzes the cause-effect relationship of break-away forces in actuated systems with nonlinear friction, combining analytical models with experimental observations to better understand the transition from sticking to sliding.

Contribution

It provides an analytical framework for understanding break-away forces in systems with nonlinear friction, integrating Coulomb, presliding, and Stribeck effects.

Findings

Break-away force depends on actuation force rate.

Analytical models align with experimental data.

Nonlinear friction effects are crucial for accurate predictions.

Abstract

The phenomenon of so-called break-away forces, as maximal actuation forces at which a sticking system begins to slide and thus passes over to a steady (macro) motion, is well known from engineering practice but still less understood in its cause-effect relationship. This note analyzes the break-away behavior of systems with nonlinear friction, which is analytically well-described by combining the Coulomb friction law with rate-independent presliding transitions and, when necessary, Stribeck effect of the velocity-weakening steady-state curve. The break-away conditions are harmonized with analytic form of the system description and shown to be in accord with a relationship between the varying break-away force and actuation force rate -- well known from the experiments reported in several independently published works.