Research On Contour Control For Feeding Servo System Of CNC Machine Tools

Accompany with the accuracy improvement of CNC machine tools,modern equipment manufacturing industry put forward higher requirements for the feed servo system controlling.For contour processing,contour error is the most affected error of all the system errors,and other errors are ultimately reflected as contour error.The traditional control method of feed servo system is to control tracking errors without coupling,which would reduce accuracy when the characteristics of different axes are not matched.In view of this situation,a single neuron adaptive cross-coupling control method based on contour error calculation model is proposed,and contour error is controlled directly.On the basis of existing contour error calculation model,this paper proposes a new contour error calculation model based on double circle weighted approximation of four points.This model only needs to consider the position information of the current point of machine tool actuator's end and four optimal interpolation points.It does not rely on the shape of contour and the value of tracking error,has high control precision,which is more obvious for the large curvature contour control.Secondly,based on the modeling of CNC feed servo system,a single neuron adaptive coupling control method is proposed as following.On one hand,each axis adopts independent classical PID control;On the other hand,a single neuron adaptive PID controller is established to compensate contour error to the servo system of each axis.In order to verify the view,this paper uses MATLAB/Simulink to conduct simulation of the mentioned calculation model and control method.Simulation results show that,the contour error calculation model based on double circle weighted approximation of four points has high accuracy,and the contour error control method can reduce the error effectively.It has a high value for improving the precision of CNC machine tools and promoting the development of numerical control technology.