Nonlinear Passive Observer for Motion Estimation in Multi-Axis Precision Motion Control

Abstract

A nonlinear passive observer (NPO) for estimating the time-varying velocity vector of a multi-axis high-precision motion control stage is presented. The proposed nonlinear estimation strategy is developed based on a Lyapunov stability analysis, which proves that the NPO is stable. Three test cases are used to investigate the performance of the proposed observer. Experimental results are given to demonstrate the performance of the proposed NPO in accurately estimating time-varying velocity during alignment, reciprocating motion, and multi-axis motion in high-precision motion control applications.

Keywords

• nonlinear observer
• passive observer
• magnetic suspension stage
• multi-axis precision motion control
• Lyapunov analysis