为了解决NURBS曲线参数插补及其实时性的问题,提出一种新的基于Steffensen迭代法的NURBS曲线参数快速求解方法。算法首先采用线性多步法进行精确的参数值预估,然后结合弓高误差、进给速度等加工条件进行自适应速度规划,再根据规划步长进行参数值迭代校正。算法不需求导,计算快速精确,满足加工精度和数控系统实时性要求。
In order to solve the problem of calculating curve parameters of NURBS interpolation and to improve the real- time performance,a method based on Steffensen iteration is proposed. Firstly,it uses a linear multistep method to estimate the parameter values precisely. Then the adaptive velocity planning is carried out with the machining conditions, such as maximum chord error and maximum feed rate. The iter- ation correction of parameters is on the basis of planning step length. The algorithm is fast and accurate, a- voiding the derivation process,which can meet the accuracy and real- time requirements of CNC systems.