NURBS曲线插补的运动规划与自适应速度插补

Motion Planning And Adaptive Federate Interpolation Based on NUBRS Curve

文章整合了以基于曲率速度插补算法与自适应速度插补规划算法,分析了NURBS曲线的特点和NURBS曲线插补的参数值的求取方法;构建了基于曲线几何特性与动力学特征插补器,几何模块提出如何决定NURBS曲线的速度尖点,并根据速度尖点信息将NURBS曲线划分为曲线段,依据弓高误差及曲线曲率规划进给速度;机床动力学模块依据每段曲线长度对加加速度控制,对于每段曲线采取相应的加减速控制规划,实现了基于S形速度曲线的加速度平滑处理,与传统插补方法相比,该插补器能够保持高速度和高精度加工性能,而且能够抑制在插补过程当中产生的轮廓误差和速度波动。

In this paper,the proposed algorithm is to combine the adaptive federate interpolation scheme with the curvature-based feedrate interpolation algorithm. The interpolator consists of the two modules： The geometric module can detect the local maximum/minimum （max/min） curvatures, and divide a NURBS curve into small segments according to the information of sharp comers. The feedrates at the sharp comers are determined based on confined chord errors and curvatures of the curve. The jerk-limited module plans the feedrate profile of the curve according to the segments＇ length and the given jerk limit. With the result,S-curve velocity profile was adopted to generate a smooth and jerk limited acceleration/deceleration （ACC/DEC） feedrate profile. In comparison with the traditional linear and circular interpolators, the NURBS interpolator can maintain small contour errors and high interpolating computing speed.