Research On Influence Rule Of Friction Parameters And Control For Feed System

The performance of the feed servo system directly affects the processing quality of products,and the nonlinear friction that exists in various kinematic pairs makes a serious damage to tracking accuracy and low-speed motion smoothness of the system. And the effect of the friction at screw-nut pair and guide pair is most prominent.In order to improve the tracking performance of the system, this paper conducted in-depth research on them.The friction between the screw and nut pairs may lead to the stick-slip vibration of the screw lead. First of all, the interacting thread of the screw and nut is expanded, and the rotation of the lead screw is equivalent to move, and a single degree of freedom model of the screw drive system is established.Then the stability of the system is studied by the method of eigenvalue analysis, and the critical condition of the instability of the screw drive system is obtained. With the help of numerical simulation and fast Fourier transform (FFT), the effects of the system structure and friction parameters on the stick-slip vibration amplitude and frequency of the screw drive system under constant driving speed are investigated.The nonlinear friction existing in the guide pair may cause the feed servo system to crawl at low speed and come into the friction dead zone during start-up and speed reversal. In this paper,the influence of the system structure and friction parameters on the crawling and friction dead zone is studied, and an adaptive sliding mode controller is designed to compensate the nonlinear friction.