Analysis of Self-Calibration Algorithms in Optical Angular Encoders

To date, two fundamental types of algorithms for self-calibration of optical angular encoders have been developed in precision goniometry, differing by the uniform or nonuniform arrangement of the read heads used in their construction. The analysis of the precision values of such encoders revealed the special features not provided by theory, which stimulated performing the experiments on modeling the expected values of such algorithms. The proposed simulation model of optical angular encoders based on a two-dimensional data array makes it possible to identify the methodological error of the measurement algorithm used by determining the residual contribution of the distorting function to the total measurement error with accuracy sufficient for practice. In addition, it makes it possible to identify the characteristic features of calibration curves constructed based on techniques with uniform or nonuniform arrangement of the reading heads. The simulation results show that self-calibration techniques based on uniform arrangement of the read heads allow for higher measurement accuracy compared to techniques based on nonuniform arrangement.