Affiliations: [a] State Key Lab of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China | [b] Department of Mechanical and Electrical Engineering, Wuhan University of Technology, Wuhan, Hubei, China | [c] Hangzhou MSTAR Technologies, Inc, Hangzhou, Zhejiang, China
Correspondence:
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Corresponding author: Xin Cheng, Department of Mechanical and Electrical Engineering, Wuhan University of Technology, Wuhan, Hubei, China. Tel.: +86 1897105852; Fax: +86 027 87557324; E-mail:chengx@whut.edu.cn
Abstract: Mover position initialization is the prerequisite to
realize the precision motion control of magnetically levitated planar
actuators (MLPAs), while its basis is the initial phase positioning. In this
paper, an estimation algorithm was proposed to position the mover's
geometric center as well as the rolling angle in motionless MLPAs. The
mechanism was that: based on the linear Hall sensors distributed at
different points in the MLPA mover, the magnetic flux density at motionless
state was measured, and then the first-order harmonic model of magnetic flux
density distribution above the magnet array was used to solve the magnetic
field phase and rolling angle at the MLPA's geometric center. Moreover, the
positioning precision was improved by adding a redundant sensor and via
rational arrangement of sensors, which ensured that data would not be
collected at the magnetic field peaks. The experiments indicate that after
addition of one redundant sensor, the maximum errors in phase positioning
and rolling positioning were both reduced.
Keywords: Initial phase, rolling angle, magnetically levitated planar actuators, hall sensors
