Study On Inetrpolation Method Of Non-rotational Symmetric Surface Turning

With the development of the aerospace and advanced technology, the highermachining accuracy of CNC machine tool is greatly demanded. In addition to theaccuracy of the machine itself, the accuracy of the interpolation algorithm also has adecisive role in determining the accuracy of CNC machining. Because of not onlysimplify the program code, but also can improving the machining accuracy, surfaceroughness,and production efficiency,NURBS(Non-Uniform Rational B-Spline)interpolation technique is being widely used.This paper carefully analyses the existing NURBS curve interpolationmethod,and proposes the estimating forward-looking NURBS interpolation algorithmwith the interpolation accuracy as the first condition. This algorithm uses the methodof forward and backward difference instead of differential to drive the fast recursiveformula of interpolation parameters, uses the interpolation parameters derived tocalculate the coordinates of interpolation points, uses the estimated function to controlthe chord error of the interpolation curve not greater than the allowed maximum errorvalue, and uses the forward-looking function to control the acceleration of each axisof the machine tool not exceeding the maximum allowable acceleration. This paperrealizes the optimization of the interpolation accuracy and acceleration, and ensuresthe accuracy of workpiece and not much machine tool impact in the machiningprocess.According to the principle and the implementation process of the estimatingforward-looking NURBS interpolation algorithm proposed in this paper, this paperachieved the interpolation trajectory simulation with the use of Matlab software,verified the superiority of the algorithm in the processing precision and accelerationcontrol. The interpolation trajectory simulation of Ring surface, Zernike surface andsine array in this paper proved the correctness and real-time property of this algorithmin the machining process of NRS.