An improved high-precision subdivision algorithm for single-track absolute encoder using machine vision techniques

Abstract

In order to achieve high-precision and robust measurement for a single-track absolute encoder, an improved subdivision algorithm based on machine vision technology is proposed. First, the composite subdivision algorithm combining RANdom SAmple Consensus and least square estimation is introduced. Second, the proposed algorithm is proved to be high-precision and effective to remove fault error from signal noise and spot by simulation. Finally, real test results show that the algorithm output angle stably achieves precision within 2.5 arc-seconds and accuracy up to 1.6 arc-seconds. Research results provide a high-precision and robust subdivision algorithm that is improved by modern machine vision technology of RANdom SAmple Consensus and it can be applied in the field of absolute angle sensor in the future.

Methods for Reducing Subdivision Error within One Signal Period of Single-Field Scanning Absolute Linear Encoder

“…The smaller the signal period, and the higher the quality of the gratings and scanning technologies, the smaller the SDE. To reduce the optical encoders’ SDE, multiple subdivision algorithms [ 17 , 18 , 19 , 20 ] have been proposed, many commercial integrated circuits [ 21 ] have been developed, and numerous gratings with special shapes [ 22 , 23 , 24 ] and devices with special dimensions [ 25 , 26 ] have been applied. Recently, the error compensation models based on particle swarm optimization have been applied to the optical encoders to compensate the SDE [ 27 , 28 , 29 ].…”

Redundant and Flexible Pseudorandom Optical Rotary Encoder

“…In the past years, different methods to increase the accuracy of optical incremental and absolute encoders have been proposed, e.g., the accuracy of the absolute encoder is increased by using the empirical decomposition method [23]. The implementation of subdivision procedure using a machine vision technique to achieve robust measurement for a single-track absolute encoder is presented in [24]. The encoder reliability assessment is considered in reference [25], where a multiple-degradation model of the encoder is developed.…”