面向高速加工的样条曲线实时插补算法

Spline Real-time Interpolation Algorithm for High-speed Machining

数控加工追求更高的加工效率和光洁的加工表面,但大多数样条曲线插补算法是根据进给速度、最大合加/减速度和合加加速度来设计的,并没有考虑如何充分利用单轴的最大加减速能力。提出一种时间近似最优的样条曲线实时插补算法,它面向数控系统对高速加工的需求,在考虑机床动态性能的基础上,充分利用单轴的最大加减速能力,以达到理论上近似最优的加工效率。同时该算法通过预处理求速度限制曲线、速度曲线反向链接和平滑处理三个步骤求出满足加工精度以及机床单轴的最大加速度、加加速度等约束条件的加工速度曲线,能有效提高加工表面的粗糙度。仿真结果表明,该算法在有效提高加工效率的同时,能实现对减速点的精确定位,得到光滑的加工速度曲线。

Higher machining efficiency and smooth machining surface are two important objectives of the CNC machining.However,most of the spline real-time interpolation algorithms are developed based on the constraints of feedrate,resultant acceleration/deceleration,and resultant jerk.The maximum acceleration/deceleration ability of each machine axis is rarely included in the design process.Thus,a time approximate optimal real-time spline interpolation algorithm is proposed and it is geared to the demand of high-speed machining of CNC system.Based on the consideration of dynamic performance of the machine tool,our algorithm makes full use of the limits on the acceleration along each machine axis to achieve the approximate optimal machining efficiency in theory.Furthermore,three steps such as computing the velocity limited curve through pretreatment,velocity curve backward chaining and smooth processing are presented to compute the machining velocity curve.The computed velocity curve can satisfy the constraint conditions such as machining precision,the limits on the acceleration and jerk along each machine axis,which also smooth the machin surface in an efficient way.By the results of simulations,it show that the algorithm can greatly improve the machining efficiency.Meanwhile,it can achieve precision localization of the deceleration points and get a smooth machining velocity curve.