Open AccessDisturbance estimation and compensation for planar motors on the long-stroke stage of a wafer stage
Author(s) -
Bizhong Xia,
Yuan Cheng,
Yong Tian,
Shuang Wu,
Kaiming Yang
Publication year - 2015
Publication title -
advances in mechanical engineering/advances in mechanical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.318
H-Index - 40
eISSN - 1687-8140
pISSN - 1687-8132
DOI - 10.1177/1687814015575987
Subject(s) - control theory (sociology) , feed forward , compensation (psychology) , stage (stratigraphy) , servo , wafer , controller (irrigation) , computer science , iterative learning control , tracking (education) , stroke (engine) , trajectory , servomotor , engineering , control engineering , control (management) , artificial intelligence , physics , mechanical engineering , psychology , paleontology , agronomy , pedagogy , electrical engineering , astronomy , psychoanalysis , biology
This article presents a data-based method to estimate and compensate low-frequency disturbance in planar motors on the long-stroke stage of a wafer stage, which is a typical multiple-input multiple-output system. First, a data-based method is introduced to decouple the multiple-input multiple-output system into multi-single-input single-output system, which is crucial for the design of controller and the correction of disturbance estimation in the scanning direction. Second, dominant low-frequency disturbances in the long-stroke stage are analyzed. Third, estimation and compensation method under moving condition is proposed. The compensation method is based on three feedforward tables, and the tables are indexed by trajectory parameters, including velocity and position instead of time in the iterative learning control method. Finally, experiments are performed on the long-stroke stage of a wafer stage to verify the proposed method. Experimental results show that the proposed method can effectively improve the servo performance by reducing the tracking errors by nearly 1/2 in the forward direction and 1/3 in the backward direction and lowering error difference between the forward and backward directions from 5.1 to 1.2 µm