Title: Force control for ultraprecision hybrid electric-pneumatic vertical-positioning device

Authors: Tomonori Kato; Youwei Xu; Tomohiro Tanaka; Kohei Shimazaki

Addresses: Department of Intelligent Mechanical Engineering, Faculty of Engineering, Fukuoka Institute of Technology, 3-30-1 Wajiro-Higashi, Higashi-Ku, Fukuoka 8110295, Japan ' Department of Intelligent Mechanical Engineering, Faculty of Engineering, Fukuoka Institute of Technology, 3-30-1 Wajiro-Higashi, Higashi-Ku, Fukuoka 8110295, Japan ' Department of Intelligent Mechanical Engineering, Faculty of Engineering, Fukuoka Institute of Technology, 3-30-1 Wajiro-Higashi, Higashi-Ku, Fukuoka 8110295, Japan ' Department of Intelligent Mechanical Engineering, Faculty of Engineering, Fukuoka Institute of Technology, 3-30-1 Wajiro-Higashi, Higashi-Ku, Fukuoka 8110295, Japan

Abstract: This study aims at the development of a control method for reducing motor loads in ultraprecision hybrid electric-pneumatic vertical-positioning devices (HVPDs), such as aspherical lens generators, that work by generating a vertical force via pressure adjustments within the balancing cylinder (BC). We also report on a proposed method for estimating the required vertical direction machining force during material processing that uses a disturbance observer. Furthermore, since our observations of the relationships among BC pressure, linear motor driving current, and vertical force have resulted in the development of a novel control method, we herein present experimental results comparing our proposed and conventional pressure control methods. These results confirm that our proposed method reduces motor loads during material processing and that the use of a disturbance observer allows the external force acting on the stage to be estimated continuously while maintaining high positioning performance.

Keywords: ultraprecision positioning; balancing cylinder; hybrid system; pressure regulator; force control; disturbance observer.

DOI: 10.1504/IJHM.2021.116948

International Journal of Hydromechatronics, 2021 Vol.4 No.2, pp.185 - 201

Received: 27 Jul 2020
Accepted: 14 Dec 2020
Published online: 09 Aug 2021 *

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