Adaptive Fuzzy Logic Proportional-Integral-Derivative Control for a Miniature Autofocus Voice Coil Motor Actuator With Retaining Force

This paper presents a miniature autofocus (AF) voice coil motor (VCM) actuator with retaining force in a restricted space that can be applied in an optical AF apparatus. A position encoder consisting of a permanent magnet (PM) and a Hall-effect sensor is used to detect magnetic signals; the displace...

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Published inIEEE transactions on magnetics Vol. 50; no. 11; pp. 1 - 4
Main Authors Yu, Hsing-Cheng, Chen, Tsan-Chen, Liu, Chien-Sheng
Format Journal Article
LanguageEnglish
Published New York IEEE 01.11.2014
The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Subjects
Actuators
Adaptation models
Adaptive optics
Coils
Design engineering
Finite element analysis
Force
Fuzzy logic
Magnetism
PD control
proportional-integral–derivative (PID) control
fuzzy logic control
Adaptive control
voice coil motor (VCM)
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ISSN0018-9464
1941-0069
DOI10.1109/TMAG.2014.2323423

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Summary:This paper presents a miniature autofocus (AF) voice coil motor (VCM) actuator with retaining force in a restricted space that can be applied in an optical AF apparatus. A position encoder consisting of a permanent magnet (PM) and a Hall-effect sensor is used to detect magnetic signals; the displacement of the AF VCM actuator can be obtained from the encoder, thus enabling closed-loop control. The proposed miniature AF VCM actuator consists of a high-permeability magnetoconductive plate and a PM on another side to generate a retaining force when the exciting current is switched off. Using a 3-D finite-element analysis simulation and the Maxwell stress tensor method, the electromagnetic Lorentz force within a movable displacement was determined to be ~16 mN. Blur caused by variable force and load disturbance was observed in images captured during AF operation. This adaptive fuzzy proportional-integral-derivative (PID) control approach compensates for the nonuniform friction, disturbance variation, and even load changes of the movable part of the AF VCM actuator that occur when a subject is photographed in various positions. The adaption mechanism reduced control effort, despite the variable force and load disturbance, and exhibited fast dynamic performance and minimal steady-state error.
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ISSN:0018-9464
1941-0069
DOI:10.1109/TMAG.2014.2323423