%0 Journal Article
%T Enhanced Sliding Mode Control with CEMF Compensation for Tracking Control of a Piezoactuated Flexure-Based Mechanism
%A Chih-Jer Lin
%A Chii-Ruey Lin
%A Shen-Kai Yu
%A Chin-Ren Hsu
%J Advances in Mechanical Engineering
%D 2014
%I SAGE Publications
%R 10.1155/2014/769192
%X This paper proposes an enhanced sliding mode controller (SMC) for piezoelectric actuator based flexural mechanism (PABFM) to track desired motion trajectories. First, based on the variable structural control approach, the proposed controller is established to accommodate parameter uncertainties, nonlinearity, and unmodelled disturbances. Because the traditional sliding-mode control cannot deal with mismatched disturbances effectively, a hysteresis counterelectromotive force (CEMF) model is proposed to describe nonlinear hysteresis effect and electric-mechanical coupling of PABFM. as Similar to the CEMF voltage for a motor caused by a changing electromagnetic field due to a rotating armature, the CEMF voltage appears to PA due to polarization and molecule friction of piezomaterial. The CEMF model is identified using a charge system search (CSS). Then, the proposed SMC with CEMF compensation is studied to deal with the mismatched nonlinear disturbances. To check the consistency of the proposed SMC controller with CEMF compensation, the simulation results were compared with the experimental results. The real-time implementation validated the tracking error better than the traditional SMC. 1. Introduction Piezoelectric actuator based flexural mechanisms (PABFM) have been designed for accomplishing ultraprecision motion with high speed in the ultraprecision positioning applications such as NANO/MEMS manipulations, because they can perform precise positioning with resolution of 1~10 nanometers at rapid response. Comparing the conventional mechanical motion mechanisms such as ball-screw stages with servo motors, PABFM possess several advantages such as zero backlash, negligible friction, high electrical-mechanical coupling efficiency, small thermal expansion during actuation, noiselessness, and easy maintenance [1, 2]. Therefore, PABFM have been extensively used in ultraprecision positioning applications, such as atomic force microscopes (AFMs), scanning electron microscopes (SEMs), and precision manufacturing [3, 4]. Speaking of the flexural stage¡¯s design, its mechanism consists of a movable stage by four parallel leaf springs with a monolithic structure [2]. Monolithic design has the advantages as follows: achieving stress-free and strain-free, more precise alignment of the stage components than other manual assembly designs and compact size [5¨C10]. Some related studies using PABFS in applications of NANO/MEMS manipulators and other recent applications are in the microsurgery and biomedical engineering [11¨C13]. Since the PA has the above advantages, creep
%U http://www.hindawi.com/journals/ame/2014/769192/