弹簧成形机几何误差的完备建模及其补偿方法研究

Complete modeling and compensation method for geometric error of spring forming machine

针对弹簧成形机成形精度低、误差大等问题,以弹簧成形机为研究对象,对弹簧成形机的几何误差进行了定义、识别、测量、建模和补偿方法研究。根据弹簧形状特征划分弹簧成形机多体系统,以多体系统理论与齐次坐标变换为理论基础,建立了包含20项几何误差的完备模型;采用Sobol灵敏度分析方法与蒙特卡洛采样方法识别出了关键误差项为刀具的定位误差;在此基础上,采用带磁力表座的千分表对刀具定位误差进行了测量,确定了误差补偿基准;最后,采用基于PMAC系统脉冲值补偿法对刀具轴定位误差进行了补偿。研究结果表明:弹簧成形机的成形过程中共有20项几何误差影响成形精度;其中,刀具定位误差影响权重为55%;误差补偿前成形机定位误差为单边误差,大小为0.3 mm,补偿后刀具定位误差减小为0.16 mm左右,定位精度提高了44.6%。通过试验,验证该方法适用于弹簧成形机几何误差补偿,填补了弹簧成形机成形精度研究方法的空白。

Aiming at the problem of low precision and large error of spring forming machine,the geometric error of spring forming machine was defined,identified,measured,modeled and compensated.According to the spring shape characteristics,the multi-body system of spring forming machine was divided.Based on the theory of multi-body system and homogeneous coordinate transformation,a complete model containing twenty geometric errors was established.By using Sobol sensitivity analysis method and Monte Carlo sampling method,the key error was identified as the tool positioning error.On this basis,a micrometer with a magnetic gauge base was used to measure the tool positioning error,and the error compensation benchmark was determined.Finally,the tool axis positioning error was compensated by impulse compensation method based on PMAC system.The results shows that there are 20 geometric errors in the forming process of spring forming machine,in which the influence weight of tool positioning error is 55%.Before error compensation,the positioning error of forming machine is a unilateral error,the size is 0.3 mm.After compensation,the tool positioning error is reduced to about 0.16 mm,and the positioning accuracy is improved by 44.6%.The experiment verifies that this method is suitable for the compensation of geometric error of spring forming machine,and fills the gap in the research method for the forming precision of spring forming machine.