A Novel Observer Design for LuGre Friction Estimation and Control

TL;DR

This paper introduces a new observer for estimating and compensating LuGre friction in motion control systems, improving tracking performance by leveraging velocity error and ensuring stability through Lyapunov analysis.

Contribution

A novel, simple observer design for LuGre friction estimation that is stable and compatible with arbitrary control inputs, enhancing control accuracy.

Findings

Improved position and velocity tracking with the proposed observer.

The observer is asymptotically stable under certain conditions.

Effective friction compensation demonstrated through simulations.

Abstract

Dynamic components of the friction may directly impact the stability and performance of the motion control systems. The LuGre model is a prevalent friction model utilized to express this dynamic behavior. Since the LuGre model is very comprehensive, friction compensation based on it might be challenging. Inspired by this, we develop a novel observer to estimate and compensate for LuGre friction. Furthermore, we present a Lyapunov stability analysis to show that observer dynamics are asymptotically stable under certain conditions. Compared to its counterparts, the proposed observer constitutes a simple and standalone scheme that can be utilized with arbitrary control inputs in a straightforward way. As a primary difference, the presented observer estimates velocity and uses the velocity error to estimate friction in addition to control input. The extensive simulations revealed that the introduced observer enhances position and velocity tracking performance in the presence of friction.