摘要
在动态状况下,实时获取机床刀具的位姿误差是提高机床精度的关键因素之一。机床多轴联动时,利用两路激光实时跟踪测量主轴测量杆上两测点的空间运动轨迹,得到两测点三维数据,并拟合出两个空间圆,用两圆的圆心连线来计算刀具的方向和位置误差。机床加工时,变化的工艺参数引起的动态运动误差和热误差变化会造成沿Z轴方向运动的滑枕误差实时变化,变化的滑枕误差会影响刀具的最终位置方向。通过自适应卡尔曼滤波预测算法对滑枕误差值进行预测-测量-修正,将计算得到的误差最优估计值替换误差补偿模型中原有的误差参数,进而对刀具位姿进行误差修正。最后,对圆锥台试件以及一个S型工件进行有误差修正补偿和未补偿加工,由测得工件的精度对比可知,采用的刀具位姿误差实时测量方法及自适应修正补偿可更加有效地提高五轴机床的加工精度。
At dynamic situation, acquiring the dynamic pose error of machine tools in real time is one of the key factors to improve the accuracy of machine tool. For multi-axis machine tool, two path lasers are used to track the space motion trajectory of two measuring points on the main-spindle measuring rod in real time. Two measuring points of 3D data are obtained and two space circles are fitted out. Then the line connecting the centre of two circles is used to identify the direction and position error of the tool. As the real-time ram errors moving along Z-axis changes with the change of the thermal error and dynamic motion error caused by the change of parameters, and the ram errors affect the final position of the tool direction. The ram errors should be predicted, measured, and corrected with the adaptive Kalman filter algorithm. The original error parameters in the error compensation model are replaced by the calculated optimal estimation value to correct the pose error of the tool. Finally, the error correction compensation and the uncompensated process are applied for the frustum specimen and the S-type workpiece. The comparison of the accuracy of the measured workpiece shows that the real-time measuring method of the tool position error and the adaptive correction compensation can effectively increase the processing accuracy of five-axis machine.
出处
《激光与光电子学进展》
CSCD
北大核心
2017年第12期231-239,共9页
Laser & Optoelectronics Progress
基金
国家自然科学基金青年项目(51205243)
安徽高校自然科学重点研究项目(KJ2016A885)
关键词
测量
位姿误差
循圆辨识
齐次坐标变换矩阵
激光跟踪仪
measurement
pose error
follow circle identification
homogenous coordinate transformation matrix
laser tracker
