Precision tracking of a piezo-driven stage by charge feedback control
Journal
Precision Engineering
Journal Volume
37
Journal Issue
4
Pages
793-804
Date Issued
2013
Author(s)
Abstract
This paper presents a novel approach for precisely controlling the motion of a piezo actuator embedded in a mechanical stage without using a displacement sensor. A piezo actuator has a high displacement resolution, but the positioning performance is degraded by hysteresis between the applied voltage and resultant displacement. However, an electromechanical model of a piezo actuator suggests that the charge flowing in the actuator is directly related to the dynamic response of the piezo displacement. Therefore, this study directly measured the charge stored in a piezo actuator, and achieved dynamic reference tracking of the actuator's displacement by regulating the charge flowing through the actuator to follow a predefined trajectory. This novel approach requires neither specially designed charge amplifier circuits nor implementation of an inverse hysteresis model. The complete model identification and the digital controller design procedure for a piezo-driven mechanical stage are presented. The charge feedback controller is designed according to the dynamic characteristics of both the actuator and the stage, so that instability is minimized relative to using a charge amplifier. The experimental results confirm satisfactory tracking performance, and reveal the influence of model uncertainties on the system performance. © 2013 Elsevier Inc. All rights reserved.
Subjects
Piezo actuator Charge control Precision servomechanism
Other Subjects
Charge control; Digital controller designs; Displacement resolution; Dynamic characteristics; Electromechanical models; Inverse hysteresis model; Positioning performance; Resultant displacement; Dynamic response; Feedback control; Hysteresis; Uncertainty analysis; Actuators
Type
journal article