Multi-domain Modeling Of Cnc Milling Machine Tool Feed System And Sensitivity Analysis Of Parameters

Choosing parameters of CNC machine tool feed system mechanical transmission parts such as the size of ball screw and the damp of mechanical components in a reasonable way has an important effect on improving the dynamic performance of CNC machine tool feed system which decides the processing quality of CNC machine. However, in actual experiments, it costs a lot of time and money to doing research on the dynamic performance of feed system when the parameters of mechanical transmission parts change. Therefore, this paper introduced computer simulation technology to study this problem. The paper built a multi-domain model of CNC milling machine tool feed system based on Modelica and completed sensitivity analysis of feed system mechanical parameters by orthogonal test design. The result showed that the dynamic performance of feed system turned bad with the increase of rotational inertial of couplings, the length and pitch of ball screw. There is a optimal value of the damp of ball screw which can make the dynamic performance best. The friction of rolling guide and rolling bearing has little effect on the dynamic performance.Firstly, this paper analyzed how the feed system works. Mathematical models of a PMSM, a control system based on 0di ? and SVPWM and a kinetic model of mechanical system were respectively established.Then, multi-domain models of PMSM, servo system and mechanical system were respectively established based on modular modeling idea by Modelica. And then connected these sub-modules to form a whole multi-domain of feed system.In order to verify the correctness of the multi-domain model, this paper not only conducted simulations under classical working condition, but also did some designed actual experiments. The results showed that simulation results of the feed system multi-domain model met expectations and error was small when compared to actual experiments. This model had good anti-jamming capability and dynamic characteristics.Finally, influences of mechanical parameters on the dynamic performance of feed system were analyzed. Based on established models, the factors which have a significant impact on the dynamic performance were found out with the help of orthogonal test and variance analysis.The study in the paper has some meanings to research on CNC machine performance. The research results can provide a reference to design CNC machine and a new idea to improve processing quality of machine tool.