非均匀有理B样条曲线直接插补进给速度规划

Interpolation feedrate planning of NURBS

在非均匀有理B样条直接插补算法中,为了提高插补实时性、克服前瞻规划算法的缺点,提出了基于进给速度预处理曲线的进给速度规划方法。该方法在插补前,通过建立进给速度预处理曲线来取代非均匀有理B样条曲线实时插补进给速度规划的前瞻算法。在速度规划过程中,为了防止进给加速度和加加速度超过机床性能要求,在曲线曲率变化较大的区域,采用基于逐点比较计算的方法规划每个参数点处的进给速度。通过MATLAB仿真表明所提方法具有较高的加工精度、良好的进给速度平滑效果和实时插补性能。

In Non-Uniform Rational B-Splines （NURBS） direct interpolation algorithm, to improve real-time performance of interpolation and to overcome the shortcomings of look-ahead algorithm, the feedrate planning method was proposed based on feedrate preprocessing curve. Before interpolation, the feedrate preprocessing curves were established to substitute look-ahead algorithm of interpolation feedrate planning. To prevent the acceleration and the jerk from exceeding the machine tool＇s capability, a method of point to point computing was used to plan the feedrate of every parameter point in the larger changes region of curvature. MATLAB simulation result showed that the proposed method could achieve higher machining precision, smoother fee＆ate contours and higher real-time performance.