Modeling and improvement of dynamic contour errors for five-axis machine tools under synchronous measuring paths
Modeling and improvement of dynamic contour errors for five-axis machine tools under synchronous measuring paths
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DOI：
10.1016/j.ijmachtools.2013.06.005
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发表时间：
2013-09
影响因子：
14
通讯作者：
Ming-Tzong Lin;Shih-Kai Wu
中科院分区：
文献类型：
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作者：
Ming-Tzong Lin;Shih-Kai Wu
提出了一种五轴机床刀具中心点轮廓误差模型，用于估计三种测量路径上的动态轮廓误差。采用伺服调整方法实现五轴动态匹配，提高了切割轨迹的轮廓跟踪性能。TCP控制功能被开发用于生成测量轨迹，其中五个轴被同时控制以使TCP保持在固定点。采用S形加减速（ACC/DEC）旋转轴插补方法，规划出光滑的五轴速度分布。将五轴运动指令代入伺服动力学模型，推导出五轴轮廓误差模型。稳态轮廓误差（SSCE）模型被证明是三个特殊的动态行为：单圈调幅，双圈效应和偏移行为。此外，该模型还被用来研究动态轮廓误差在三维空间中的变化行为。分析了初始安装位置、进给速度和五轴伺服增益等因素对动态轮廓误差的影响。通过在测量路径CK 1、CK 2和CK 4下开发的伺服调谐过程，显著减小了由伺服失配引起的轮廓误差。最后，在台式五轴雕刻机上进行了实验，验证了所提出的方法可以显着提高TCP的动态轮廓精度。
In this paper, a contour error model of the tool center point (TCP) for a five-axis machine tool is proposed to estimate dynamic contour errors on three types of measuring paths. A servo tuning approach to achieve five-axis dynamic matching is utilized to improve contouring performance of the cutting trajectory. The TCP control function is developed to generate measuring trajectories where five axes are controlled simultaneously to keep the TCP at a fixed point. The interpolation method of the rotary axes with S-shape acceleration/deceleration (ACC/DEC) is applied to plan smooth five-axis velocity profiles. The contour error model for five axes is derived by substituting five-axis motion commands into servo dynamics models. The steady state contour error (SSCE) model is demonstrated to illustrate three particular dynamic behaviors: the single-circle with amplitude modulation, double-circle effect and offset behavior. Furthermore, the model is also utilized to investigate the behaviors of dynamic contour errors change in 3D space. The factors that affect dynamic contour errors, including the initial setup position, feedrate and five-axis servo gains, are analyzed. With the developed servo tuning process under the measuring paths (CK1, CK2 and CK4), the contour errors caused by servo mismatch are reduced remarkably. Finally, experiments are conducted on a desktop five-axis engraving machine to verify the proposed methodology can improve dynamic contouring accuracy of the TCP significantly.