Look-Ahead Control in High Feed Rate NURBS Curve Interpolation

Using t wo-step GA,the NURBS curve is pretreated to get the maxi mum curvature points where the feed direction changes abruptly.Hybrid constraining equations containing dynamic characteristics of CNC machine tool and intrinsic geo metric property of NURBS curve are established.As a result,the look-ahead control infor mation co mposed of each maxi mum curvature point,safe feed rate for passing through the point,and decelerating point aheadis generatedin real-ti me to achieve high precision,high efficiency,and high stability of curve interpolation.