An Optoelectronic Angular Encoder Based On Double Track Absolute Encoding

With the development of manufacture and auto-technology, encoders, the combination of digital and computer technology, have been widely applied into practice. Recent years, the miniature encoders have made challenges to the traditional ones. It seems that the study of new coding theory, the invention of new types of coding disk, and the using of advanced electronic technology in development of new absolute photoelectric encoders have been a tendency in the future.This paper, absolute encoder based on double track, is focused on the study of new absolute electronic coding system. According to reading position of photoelectric elements, it can be categorized into the double track absolute encoder with uniformly distributed probes and the double track absolute encoder with non-uniformly distributed probes.This paper puts forwards the generation of the two new absolute angular encoders. By a specially designed 7 bit encoding track and a 4 bit matrix encoding track, an absolute 11 bit double track encoding disk can be composed easily and accurately. Combining two 6 bit encoding tracks with non-uniformly distributed probes, an absolute 12 bit double track encoding disc can be composed. Reading probes are distributed on two circles separately, so that space can be saved significantly. Difficulties of design for high rank single track absolute encoding are avoided and there is no cursory error. So it is in favor of miniaturization and reducing cost.The 11 bit double track absolute encoder is designed for elevator, so that incremental encoders which are used widely can be replaced. Close loop position control is realized. The design also includes an electronically clearing function to completely meet various application situations of the encoder, so that time and manpower can be saved significantly in system debugging. The 12 bit double track absolute encoder exports 3600 absolute position information, and it realizes equation of circle angle. These two codes respectively have different advantages and can be applied to different range of projects.The double track absolute angular encoder overcomes the disadvantage of increasing the accuracy at the expense of more tracks and difficulties of fabrication. Therefore, it establishes a new approach for the high-accuracy and the miniaturization of the absolute angular encoder.