Abstract: The first two parameters can not be calculated by current predictor-corrector NURBS interpolation algorithm, and the iteration times for parameter correction can not be controlled. Therefore, this paper puts forward a modified predictor-corrector NURBS interpolation algorithm. The parameter is predicted. Whether the predicted parameter is far beyond the expected parameter is checked according to maximum feed step, chord error and normal acceleration. If the error is in allowable error range, the parameter increment will be ajusted, otherwise it needs iteration correction. The results of simulations demonstrate that the iteration times for parameter correction of this new method are much less than those of current method because of parameter increment ajustment. It is more conducive to real-time interpolation.

Key words: Non-Uniform Rational B-Spline（NURBS）, predictor-corrector, chord error, parameter increment

摘要： 现行的NURBS曲线参数预估校正插补方法不能预估最开始的两个参数，而且不能控制预估参数迭代修正的次数。提出改进的NURBS预估校正插补方法，该方法预估插补点参数，根据最大进给步长约束、轮廓误差约束以及法向加速度约束，判定预估参数与实际参数的误差，当误差在允许范围内，则对参数步长增量进行调整，否则进行迭代修正。仿真实验结果表明，新方法通过对参数步长增量的调整，使得预估参数更加接近实际参数，较现有方法有效减少了参数迭代修正的次数，利于实时插补的实现。

关键词: 非均匀有理B样条曲线（NURBS）, 预估校正, 轮廓误差, 步长增量