Research On Accurate Interpolation Of Machining Path Based On Impulse Response Technology

High speed and high precision CNC machining technology is widely used in the field of aviation and home appliance industry to improve the machining quality and efficiency.CNC machining mainly uses linear(G01)and circular arc(G02 or G03)instructions to implement tool path feed.The corner contour error at the connection of short line segments of the machining path cannot be determined.This situation will cause the machine to vibrate violently and affect the quality of the surface of the machined part.To solve this problem,this paper aims to construct a precise interpolation algorithm of machining path contour error based on the finite impulse response technology.The method can make the speed and acceleration of the feed motion during processing continuous and effectively reduce the vibration of the machine tool.In this paper,the speed control technology is considered synthetically and the finite impulse response filter is used to explore the corner contour error of the machining path.Consider the three aspects of the corner contour of a circular curve,the corner contour of a short line segment,and the corner contour of a transition between a straight line and an arc.The speed curve of the tool path is deeply analyzed and an accurate interpolation algorithm that can effectively control the corner contour is proposed.The main research contents and achievements of this paper are as follows:Firstly,this paper introduces the key technologies and research status of high-speed machining,the advantages and disadvantages of spline interpolation technology and finite impulse response technology are compared,and the finite impulse response technology is adopted to study the contour error of the corner.Secondly,the acceleration and deceleration control method based on convolution of finite impulse response technology is analyzed in this paper,the movement of the feed axis and the speed characteristics of each axis are explored.Thirdly,based on the finite impulse response technology,an accurate contour interpolation algorithm is proposed for the corner at the junction of short line segments.The single axis short line segments are convoluted to generate a high-order trajectory reference path.Under the limit speed constraint of the driver,by controlling the overlapping time at the junction of short line segments,the contour error of the corner is obtained by using the speed integral at the corner.The algorithm is verified by experiment and simulation.The method can effectively control the contour error of the corner in the optimal time,and can realize the smooth transition at the corner to reduce the vibration of the tool.The instructions in the CNC system are not only for the linear segment(G01),but also arc curves(G02 or G03)in the CNC system.The problem of the contour error of arc curves can be solved in the subsequent research.Fourthly,for the contour error of arc curve in CNC system,the speed and acceleration of the arc curve transition point are constrained.The pulse velocity curve of arc curve is obtained by using the finite pulse response technology.The parameter relationship between the reference path and the interpolation path is established,getting contour error by parameter equation.The contour error of arc curve is obtained by solving.Constraints are established for the speed and acceleration of the transition points of the arc curve to control the corner contour error of the mixed curve.In summary,the contour error of high-speed machining corner of straight line,arc curve and mixed curve is studied,and the corresponding interpolation algorithm is proposed.Under the optimal machining time,the contour error of corner is determined,the smooth transfer of speed and acceleration is realized,and the machining quality is improved.