TY - JOUR
T1 - High-precision absolute linear encoder based on a standard calibrated scale
AU - Lashmanov, Oleg U.
AU - Vasilev, Aleksandr S.
AU - Vasileva, Anna V.
AU - Anisimov, Andrei G.
AU - Korotaev, Valery V.
PY - 2018/7/1
Y1 - 2018/7/1
N2 - This paper presents the full research and development cycle of a high-precision absolute linear encoder based on a standard calibrated scale. Already available and used in industry standard scales of invar alloy were employed in the study. The scales have incremental indexes with 1 mm spacing intervals without an absolute code. However, the existing technical task is to measure the absolute position in the range of 2 m with accuracy less than 5 μm. For that, the developed encoder rationally combines magnetic measuring channel for the index numbering and an optical channel for the precise estimation of the encoder position. First, for the development, a simulation was performed to synthesize and analyze an image of an index. This image was used to develop a real-time double-threshold image processing algorithm to estimate the index position. Later the developed image processing algorithm was verified by preliminary testing and supported by a presented three-stage calibration procedure. The final measurements proved that the designed and developed encoder has the accuracy of 1.65 μm (3 standard deviations) at the speed up to 3 m/s. The possibility of use of standard calibrated scales with the presented encoder to solve existing and new industrial tasks forms the value of this paper. A possible use of the existing scales also provides unification and compatibility with conventional metrology equipment.
AB - This paper presents the full research and development cycle of a high-precision absolute linear encoder based on a standard calibrated scale. Already available and used in industry standard scales of invar alloy were employed in the study. The scales have incremental indexes with 1 mm spacing intervals without an absolute code. However, the existing technical task is to measure the absolute position in the range of 2 m with accuracy less than 5 μm. For that, the developed encoder rationally combines magnetic measuring channel for the index numbering and an optical channel for the precise estimation of the encoder position. First, for the development, a simulation was performed to synthesize and analyze an image of an index. This image was used to develop a real-time double-threshold image processing algorithm to estimate the index position. Later the developed image processing algorithm was verified by preliminary testing and supported by a presented three-stage calibration procedure. The final measurements proved that the designed and developed encoder has the accuracy of 1.65 μm (3 standard deviations) at the speed up to 3 m/s. The possibility of use of standard calibrated scales with the presented encoder to solve existing and new industrial tasks forms the value of this paper. A possible use of the existing scales also provides unification and compatibility with conventional metrology equipment.
KW - Automatic positioning
KW - High-precision measurements
KW - Imaging encoder
KW - Invar scale
KW - Linear optical encoder
UR - http://www.scopus.com/inward/record.url?scp=85044735073&partnerID=8YFLogxK
U2 - 10.1016/j.measurement.2018.03.071
DO - 10.1016/j.measurement.2018.03.071
M3 - Article
AN - SCOPUS:85044735073
SN - 0263-2241
VL - 123
SP - 226
EP - 234
JO - Measurement
JF - Measurement
ER -