Design algorithm of systems for automatic control of mechanical processing accuracy on CNC machines

Abstract

The article proposes a structural diagram of the processing precision control system for a CNC
lathe, using a control algorithm based on statistical forecasting. The scheme of the control system can
be applied to different machines with different CNC systems; the main condition is that the CNC
system allows the connection of a third-party electronic computer (EC). Using the example of a
16K20F3 machine with the help of a 2P22 CNC control system, the application of the accuracy
control scheme and its mathematical support, which includes both algorithms for calculating
correction values and procedures for choosing the optimal sequence, is considered in the article. The
stages of accuracy assessment are considered separately, and the detailed algorithms "Estimation of
tuning error and confidence limits" and "Determination of the scope of independent random factors"
are presented. As a result of the conducted research on automatic sub-tuning according to the
processing precision control algorithm, it was found that the original sequence of part sizes (that is,
the sizes of parts manufactured with sub-tuning) has a constant average value, slightly different from
the specified size, and a correlation function slightly different from zero, which indicates a complete
exhaustion of possibilities of a further increase in the accuracy of processing by automatic debugging
methods, i.e. by using information about the dimensions of previously processed parts.