Research On Spline Interpolation Algorithm And Velocity Optimization Of CNC System

China is a manufacturing country,and advanced CNC machine tools are the key to manufacturing.With the rapid development of CNC machining technology and the realization of spline interpolation in CNC system,the machining quality of products has been greatly improved.However,due to the limitation of various factors,numerical control system still faces many urgent problems in the process of interpolation processing,such as complicated calculation and large fluctuation of speed.These problems are mainly reflected in two aspects:real-time computation of interpolation parameters and interpolation speed planning.Therefore,this paper mainly studies two problems of spline interpolation parameters calculation and interpolation speed optimization of CNC system.Taking the general CNC system as the research object,it explores feasible calculation methods of fast interpolation parameters and small fluctuation speed optimization algorithm.The main research contents are as follows:(1)Research and analysis of the mathematical principle of cubic B-spline curve.The related mathematical theory and parameter expression form of cubic uniform B-spline curve modeling were studied deeply,and the global processing was carried out on the basis of local expression.The principle of spline curve segment connection is studied to provide theoretical basis for parameter calculation and velocity optimization of subsequent interpolation.(2)The proposal and improvement of high efficiency and high precision interpolation parameter calculation method.Numerical control system in the process of the spline curve interpolation calculation of interpolation points are actually interpolation parameter calculation,namely according to the current interpolation cycle planning feed speed_iV to get the corresponding feeding step length(35)L_i,its generation into the parameter expression of spline curve can be incremental solution of the corresponding parameters(35)u_i,the parameter value of the next interpolation point is obtained by the recursive formulau_i(10)1(28)u_i(10)(35)u_i.In this paper,a variety of interpolation algorithms are studied,the rapid recursive differential equation method of Adams is corrected and improved,and a more concise and effective"cubic polynomial U-S"interpolation parameter calculation method is proposed,which not only significantly reduces the velocity fluctuation,but also ensures the real-time performance of interpolation.(3)The paper presents and realizes the optimization algorithm of uniform velocity in segment and intersegment transfer interpolation.Due to the complexity and diversity of the curve shapes to be processed in practical engineering applications,the curvature changes may be rapid or slow.If the processing feed speed cannot be updated in real time or predicted in advance according to the curve shape,it is likely to cause machine tool tremor or even damage to the equipment.Based on this,the research of interpolation speed optimization algorithm is carried out in this paper.The simulation results show that this method can achieve the local constant and reasonable transition of feed speed and solve the above problems well.