Absolute capacitive grating displacement measuring system with both high-precision and long-range

摘要

'In this paper, we propose an absolute capacitive grating displacement measuring system with both high-precision and long-range. This system includes a MOVER and a STATOR. A thin layer of dielectric film is respectively grown on concact surfaces of the MOVER and the STATOR. The MOVER moves along the length direction of the system relative to the STATOR in a contact mode to minimize the measurement error caused by gap change. The system is able to generate eight signals at any displacement position, and with these signals, the measuring system is capable of measuring absolute displacement with both high-precision and long-range. Investigations involve the principle, simulation, fabrication and experiment setup, results and discussions. The experimental results show that the system has good repeatability and the resolution can reach as high as +/- 1.7 nm with a range of 2.8 mm. It is also shown that the precision of the measuring system in the displacement range of 7 mm reaches +/- 50 nm. The same system can be extended to achieve both nanometers precision and hundred millimeters range. (C) 2019 Elsevier B.V. All rights reserved.