Optimizing the Scanning Throughput of a Stick-Slip Piezoelectric Actuator by Exploring the Scannable Trajectory Set

Stick-slip piezoelectric actuators are promising because they enable both macroscale motion in stepping mode and nanoscale motion in scanning mode. However, when the scanning range and frequency are significant, the slip motion between their driving foot and end-effector is always possible, leading to the unwanted transition between scanning and stepping modes. Aiming to fully exploit the scanning capability of a stick-slip piezoelectric actuator, this article proposes a novel method for exploring the actuator's scannable trajectory set. A dynamic model that cascades the actuator's linear dynamics and the frictional relationship between its driving foot and the end-effector is established. Then, parameters are identified based on the actuator's response. With these parameters, the scannable trajectory set of the actuator can be analytically obtained. The high consistency between the experimental results and the model predicted set validates the effectiveness of the proposed method. The exploration of the set paves the way for the high-throughput scanning of the stick-slip piezoelectric actuator. As a demonstration, a high throughput (scanning range $\boldsymbol{\times}$ frequency) of 3000 $\boldsymbol{\mu}$m $\boldsymbol{\times}$ Hz is realized at arbitrary macro positions in the cross-scale nanopositioning test, by a typical stick-slip actuator, improving 1–2 orders of magnitude over existing ones.

I. Introduction

Nanopositioning systems with ultrahigh precision have opened new perspectives for many cutting-edge developments such as atomic force microscope [1], robotic manipulator [2], ultraprecision machine tool [3], and auto-focusing device [4].