Sliding-mode control of a three-degrees-of-freedom nanopositioner
Journal
Asian Journal of Control
Journal Volume
10
Journal Issue
3
Pages
267-276
Date Issued
2008
Author(s)
Abstract
This paper presents the sliding-mode control of a three-degrees-of-freedom nanopositioner (Z, Dx, Oy). This nanopositioner is actuated by piezoelectric actuators. Capacitive gap sensors are used for position feedback. In order to design the feedback controller, the open-loop characteristics of this nanopositioner are investigated. Based on the results of the investigation, each pair of piezoelectric actuators and corresponding gap sensors is treated as an independent system and modeled as a first-order linear model coupled with hysteresis. When the model is identified and the hysteresis nonlinearity is linearized, a linear system model with uncertainty is used to design the controller. When designing the controller, the sliding-mode disturbance (uncertainty) estimation and compensation scheme is used. The structure of the proposed controller is similar to that of a proportional integral derivative controller. Thus, it can be easily implemented. Experimental results show that 3-nm tracking resolution can be obtained.
Subjects
Capacitive sensors
Controllers
Degrees of freedom (mechanics)
Hysteresis
Linear systems
Piezoelectric actuators
Piezoelectricity
Proportional control systems
Sliding mode control
Two term control systems
Estimation and compensation
Hysteresis non linearities
Linear system model
Nano-positioner
Open loop characteristic
Precision, nonlinear
Proportional integral derivative controllers
Three degrees of freedom
Feedback
Type
journal article