title: Direct and precise measurement of displacement and velocity of flexible web in roll-to-roll manufacturing systems.
abstract: Interest in the production of printed electronics using a roll-to-roll system has gradually increased due to its low mass-production costs and compatibility with flexible substrate. To improve the accuracy of roll-to-roll manufacturing systems, the movement of the web needs to be measured precisely in advance. In this paper, a novel measurement method is developed to measure the displacement and velocity of the web precisely and directly. The proposed algorithm is based on the traditional single field encoder principle, and the scale grating has been replaced with a printed grating on the web. Because a printed grating cannot be as accurate as a scale grating in a traditional encoder, there will inevitably be variations in pitch and line-width, and the motion of the web should be measured even though there are variations in pitch and line-width in the printed grating patterns. For this reason, the developed algorithm includes a precise method of estimating the variations in pitch. In addtion, a method of correcting the Lissajous curve is presented for precision phase interpolation to improve measurement accuracy by correcting Lissajous circle to unit circle. The performance of the developed method is evaluated by simulation and experiment. In the experiment, the displacement error was less than 2.5 μm and the velocity error of 1σ was about 0.25%, while the grating scale moved 30 mm.
authors.affiliation: Advanced Manufacturing Systems Research Division, Korea Institute of Machinery and Materials, 156 Gajeongbuk-Ro, Yuseong-Gu, Daejeon 305-343, South Korea.
authors.forename: Dongwoo
authors.initials: D
authors.lastname: Kang
authors.affiliation: Nano-Opto-Mechatronics Lab., Dept. of Mechanical Eng., KAIST, 335 Gwahangno, Yuseong-Gu, Daejeon 305-701, South Korea.
authors.forename: Young duk
authors.initials: Yd
authors.lastname: Kim
authors.affiliation: Advanced Manufacturing Systems Research Division, Korea Institute of Machinery and Materials, 156 Gajeongbuk-Ro, Yuseong-Gu, Daejeon 305-343, South Korea.
authors.forename: Eonseok
authors.initials: E
authors.lastname: Lee
authors.affiliation: Advanced Manufacturing Systems Research Division, Korea Institute of Machinery and Materials, 156 Gajeongbuk-Ro, Yuseong-Gu, Daejeon 305-343, South Korea.
authors.forename: Young-Man
authors.initials: YM
authors.lastname: Choi
authors.affiliation: Advanced Manufacturing Systems Research Division, Korea Institute of Machinery and Materials, 156 Gajeongbuk-Ro, Yuseong-Gu, Daejeon 305-343, South Korea.
authors.forename: Taik-Min
authors.initials: TM
authors.lastname: Lee
authors.affiliation: Korea Research Institute of Standards and Science, 267 Gajeong-Ro, Yuseong-Gu, Daejeon 305-340, South Korea.
authors.forename: Dongmin
authors.initials: D
authors.lastname: Kim