DEVELOPMENT OF FUZZY CNC LATHE DRIVE CONTROL SYSTEM BASED ON SHARED ACCESSORY FUNCTIONS
Authors:   Omsk State University, Khamitov R. N. , Zykin P. V. ,   Tyumen Industrial University, Glazyrin A. S. ,   National Research Tomsk Polytechnic University
Published: March 2022

Relevance As part of the study, a control system for driving the supply of a CNC lathe based on fuzzy logic was developed using the MATLAB software package. The development is carried out on the basis of experimentally defined (both theoretically and empirically) shared functions of belonging (including Gauss functions and sigmoidal functions built on a single basis). This avoids the appearance of stagnant zones where the regulator does not respond to changes in the incoming parameters of the control object. The results obtained showed the development efficiency, which is expressed by the economical use of the synchronous motor life. Economy is achieved due to surface roughness sensor provided in control system. As a result of the design of the control system, it is possible to adjust the speed of rotation of the motor, and the quality of the machined surface of the part. It is worth noting that the regulation is based on the empirical dependence of the roughness of the processed surface of the part on the radius at the tip of the cutter and the supply. Coherence and sequence of functioning of system components allowing for control of fuzzy values of electric motor parameters is ensured by developed transfer function of ball-screw pair. To share the two components of the system, the transfer function is mathematically derived, the correctness of its calculations is confirmed graphically. For the operation of the CNC lathe motor control system based on fuzzy logic, a fuzzy rule unit has been developed. The unit functionality provides for stabilization of the motor rotation speed in case of three main situations: with an increase in the indicator from the norm, with its mismatch to the lower side and with full compliance. Its operation is arranged in such a way that due to the previously specified conditions it is possible to detect inconsistencies of fuzzy values of the set of parameters. In general, it is worth noting that the effectiveness of the resulting development was confirmed experimentally, the results of the experiment make it possible to assert that the electric motor control system functions properly and is effective at all stages of the electric drive operation. Aim of research Develop a fuzzy logic control system model to drive the longitudinal feed of the CNC lathe. To form a rule block of a fuzzy control system that facilitates its operation on the entire surface of a fuzzy set without stagnant zones. Research methods As part of the study, a model of a fuzzy control system was developed using the MATLAB package, the results showed that the development functions on the entire surface of a fuzzy set, without stagnant zones. Fuzzy regulator rule block is formed. This facilitates the operation of the control system on the entire response surface, that is, the ability to control the synchronous motor performance at all stages of the part processing process. Results As part of the study, a fuzzy logic control system was developed to drive the longitudinal supply of the CNC lathe. The system is based on shared membership functions built on a single basis. A number of mathematically formulated transfer functions have been developed, which provide correction of the rotation speed of the synchronous motor, consistent transmission of the obtained data to subsequent control system units for further control of the rotation speed of the cutting tool. To ensure the operation of the control system, a fuzzy rule unit has been developed, which consists of three control directions, the operation of which is automatically determined by the control system based on data on non-conformity of parameters obtained from a specially provided surface roughness sensor of the machined part.