Statically Stable Charge Sensing Method for Precise Displacement Estimation of Piezoelectric Stack-Based Nanopositioning

Abstract

Piezoelectric self-sensing is a promising displacement estimation technique that has captured a broad range of attention since its origin. However, one long-standing and critical issue associated with this technique is its unstable static performance. This issue significantly undermines the sensing accuracy and the long-term reliability, which are primary concerns in industrial applications. In this article, we show that this challenging issue can be finally solved. The proposed solution consists of two steps. First, we develop a novel charge sensing circuit that provides an explicit access to observe any disturbance that might impact the static sensing. Second, by introducing cascaded observers, a self-improvement sensing scheme is developed. High accuracy displacement estimate can, thus, be reconstructed by fusing the reference signal, the observed disturbance, and the original sensing signal together. Experimental validations demonstrate the expected stable performance. The root-mean-square sensing errors are well below 1%. The developed self-sensing technique is a competitive solution for nanopositioning applications, also due to its self-contained, immunity to environmental disturbance, and plug-and-play features.