离轴抛物面超精密加工轨迹时间序列控制方法  

Time Series Control Method for Off-axis Paraboloid Ultra Precision Machining

作　　者：蔡杨 CAI Yang(Zhejiang Yongcheng Machinery Co.,Ltd.,Zhuji 311835,China)

机构地区：[1]浙江永成机械有限公司,浙江诸暨311835

出　　处：《机械工程师》2024年第3期145-149,共5页Mechanical Engineer

摘　　要：离轴抛物面超精密加工轨迹容易出现不可控轴与可控轴位置势函数不一致现象,影响加工次序,导致加工效果不理想。针对该问题,提出了离轴抛物面超精密加工轨迹时间序列控制方法。分析离轴抛物面超精密加工过程,计算点与点之间的旋转角度。以机床零点为基准,将笛卡尔坐标系中零件外形表达式转化到柱坐标系中,使工件方程的坐标系完成转换。将加工轨迹点时间间隔映射成0~1的数值,设定各个处理时间内时间权重,使得各个加工时间点间交互作用。检测基于轨迹点分布聚簇性的加工轨迹,分析加工轨迹聚集特性,消除各种轨迹之间的时间间距对轨迹的影响。采用PMAC的时基控制方式,保证不可控轴与可控轴位置势函数一致。以移动点更新速率为主要计算参量,将实时输入频率作为时基控制的输入频率,以非控制轴为输出频率,由此实现加工轨迹时间序列的时基控制。通过试验验证结果可知,该方法能够获取以(-150,300,0)为加工轨迹中心的完整超精密加工轨迹,且不会出现投影畸变现象,有效控制加工轨迹时间序列。The ultra precision machining path of off-axis paraboloid is prone to the inconsistency of the position potential functions of the uncontrollable axis and the controllable axis,which affects the machining sequence and leads to the unsatisfactory machining effect.To solve this problem,a time series control method for off-axis paraboloid ultra precision machining trajectory is proposed.The ultra precision machining process of off-axis paraboloid is analyzed,and the rotation angle between points is calculated.Based on the zero point of the machine tool,the part shape expression in the Cartesian coordinate system is transformed into the cylindrical coordinate system,so that the coordinate system of the workpiece equation is transformed.The time interval of the machining path points is mapped to a value of 0~1,and the time weight within each processing time is set to make each processing time point interact with each other.The machining path based on the clustering of the path points distribution is detected,the clustering characteristics of the machining path are analyzed,and the impact of the time interval between various paths on the path is eliminated.PMAC time base control mode is adopted to ensure that the position potential function of uncontrollable axis is consistent with that of controllable axis.Taking the update rate of moving points as the main calculation parameter,the real-time input frequency is used as the input frequency of time base control,and the non-control axis is used as the output frequency,thus realizing the time base control of the time series of machining paths.The experimental results show that the method can obtain the complete ultra precision machining path with(-150,300,0)as the machining path center,without projection distortion,and effectively control the time series of machining path.

关 键 词：离轴抛物面 超精密 加工轨迹 时间序列控制 

分 类 号：TP208[自动化与计算机技术—检测技术与自动化装置]