基于四次多项式的数控加工运动处理算法研究

Research on CNC Machining Motion Processing Algorithm Based on Four-Order Polynomial

在数控加工中,机床振动会恶化切削过程,数控进给运动不平滑是造成机床振动的一个重要原因。但现有直线加减速、S曲线加减速方法中,加加速度是阶跃变化的,会引起机床柔性冲击。研究了一种基于四次多项式的数控加工运动处理算法,在保证加加速度连续变化基础上,根据运动学约束条件(机床最大允许加速度、最大加加速度、加工程序段位移、指令进给速度),对各种运动轮廓进行平滑处理,以减小机床振动和冲击。该算法可减小加加速度阶跃变化所带来的机床柔性冲击,对数控进给系统的运动平滑性具有重要意义。

Machine tool vibration will deteriorate the cutting process in machining. And the unsmooth of feed motion is an important cause of machine vibration. But the jerk curves in the linear acceleration and de- celeration, S curve acceleration and deceleration method, are step-change and cause the machine tools flexi- bility impact. So the CNC machining motion processing algorithm based on four-order Polynomial is devel- oped, which ensures the continuous change of jerk. The proposed algorithm can smooth each motion profile in order to reduce machine tools vibration, according to kinematical constraints such as maximum permissi- ble acceleration, the maximum jerk, processing program segment displacement, command feed rate. The al- gorithm can reduce machine tools flexibility impact result from jerk step-change, and is helpful to obtain smooth machine tools feed motion.