Resetting Disturbance Observers with application in Compensation of bounded nonlinearities like Hysteresis in Piezo-Actuators

TL;DR

This paper introduces a novel reset disturbance observer for piezoelectric actuators that effectively compensates for nonlinearities like hysteresis, improving performance over traditional linear methods.

Contribution

A new reset disturbance observer based on reset control and CgLp elements is proposed, addressing limitations of linear DOBs in nonlinear actuator compensation.

Findings

RDOB outperforms linear DOB in hysteresis compensation

Stability criteria for RDOB configurations are established

Experimental results confirm performance improvements

Abstract

This paper presents a novel nonlinear (reset) disturbance observer for dynamic compensation of bounded nonlinearities like hysteresis in piezoelectric actuators. Proposed Resetting Disturbance Observer (RDOB) utilizes a novel Constant-gain Lead-phase (CgLp) element based on the concept of reset control. The fundamental limitations of linear DOB which results in contradictory requirements and in a dependent design between DOB and feedback controller are analysed. Two different configurations of RDOB which attempt to alleviate these problems from different perspectives are presented and an example plant is used to highlight the improvement. Stability criteria are presented for both configurations. Performance improvement seen with both RDOB configurations compared to linear DOB is also verified on a practical piezoelectric setup for hysteresis compensation and results analysed.