动态性能约束多轴联动数控机床工作精度建模研究  

Modeling for working accuracy of multi-axis synchronous numerical control machine with dynamic performance constraints

作　　者：郭小兰[1] 起雪梅[1] 张敬东[1] 

机构地区：[1]攀枝花学院交通与汽车工程学院,四川攀枝花617000

出　　处：《中国农机化学报》2016年第12期41-47,共7页Journal of Chinese Agricultural Mechanization

摘　　要：高速铣削复杂轮廓常采用微小线段逼近轮廓曲线的加工方式来保障工件加工精度。由于数控机床各运动轴动态性能的制约,在实际切削时不稳定的进给速度导致产生轮廓误差。本文提出一种基于动态性能约束的数控机床工作精度检验的轮廓误差模型,以G代码转换成轴运动位移指令作为输入,采用段内S型加减速时间反算法,将计算出的最大速度作为各段运动速度,对段间加减速衔接处理,得到各运动轴速度指令,利用伺服系统传递函数模型求解出各运动轴的位移量,通过空间几何变换到刀具运动轨迹,重新拟合轮廓曲线得到轮廓误差。针对不同动态参数变化,仿真出轮廓误差与动态指标之间关系,实现对数控机床高速加工时动态指标引起的轮廓误差的考察。Generally, micro line segments approximation method has been used for ensuring accuracy of work pieces in multi-axis highspeed milling. With the dynamic performance constraints of CNC machine tools＇ axial motion, additional contour error and worse surface quality caused by the feed-rate instability. An accuracy model with dynamic performance constraints to testing contour error was proposed, which make displacement instructions converted from G code as input, maximum speed calculated by acceleration and decel- eration control algorithm as running speed of each segments, and then used for link segment. Axial motion servo control system model was used to calculate the axis moving displacement, and then transformed to the trajectory of tip and refitted the profile of work piece. According to a series of dynamic parameters, relationships between contour error and dynamic indexes were simulated. It is shown that the proposed model can provide an available clue for estimating the CNC machine performance from contour errors effectively and quickly.

关 键 词：多轴加工 动态指标 加减速控制 轮廓误差 

分 类 号：TG659[金属学及工艺—金属切削加工及机床]