数控机床几何误差单轴五次测量与辨识方法

CNC machine tool geometric error single-axis and five-times measurement and identify method

针对数控机床几何误差项的准确测量与辨识问题,提出了一种基于激光干涉仪的机床空间几何误差单轴五次测量与辨识方法。首先,针对X、Y、Z轴分别设置了一条测量线,测量了3条划定线上除滚转误差外的其他15项几何误差,共计15次测量;然后,分析了转角误差对直线度误差以及直线度误差对定位误差的耦合影响,并建立了误差辨识方程组;最后,根据误差辨识方程组,得到了机床21项几何误差;并进行了单轴五次测量法的测量和辨识实验,并将所得结果与空间九线法测量辨识结果进行了对比分析。研究结果表明:单轴五次测量法与空间九线法测量辨识结果的空间误差向量最大偏差为1.93μm,平均偏差为0.58μm,该结果验证了单轴五次测量法是准确和有效的。该方法考虑了实际测量过程中的误差耦合情况,因此相比于空间九线法,该方法减少了测量线数与测量次数,简化了误差项的求解过程;同时,采用单轴运动方式可以有效避免其他轴对当前运动轴误差的影响。

To address the accurate measurement and identification issues of geometric error items in computer numerical control(CNC)machine tools,a single-axis and five-times measurement method based on the laser interferometer for machine tool spatial geometric error was proposed.Firstly,individual measurement lines were established for the X,Y,and Z axes.On these three delineated lines,the other 15 geometric errors,excluding the roll error,were measured meticulously,amounting to a total of fifteen measurements.Then,the coupling effects of angle errors on straightness errors and the influence of straightness errors on positioning errors were scrutinized and analyzed.To achieve this,error identification equations were established,and these complexities and interactions was considered to ensure that the identified errors were representative of the actual machine tool performance.Finally,the 21 geometric errors of the machine tool were ascertained by employing the error identification equations.The measurement and identification experiments based on the single-axis and five-times measurement method were compared with the identification results of the spatial nine-line method.The research results show that the maximum deviation of the spatial error vector between the measurement identification results of the single-axis and five-times measurement method and the spatial nine-line method is 1.93μm,while the average deviation is 0.58μm.It is proved that the single axis five times measurement method is accurate and effective.This method considers the error coupling in the actual measurement process.Comparing to the spatial nine-line method,the number of measurement lines and measurement times were reduced by this method,and the process of solving the error term was simplified.By adopting a single axis motion method,the impact of other axes on the current motion axis error was effectively avoided.