摘要
针对全闭环数控回转轴的关键检测元件—圆光栅的安装误差引起回转轴定位精度差的问题,基于圆光栅测量角度的工作原理,分析了圆光栅在安装时由于光栅定位端面的跳动误差对莫尔条纹的影响规律,推导出了相应的数学关系,建立了回转轴定位误差与光栅定位端面的跳动误差之间的数学模型。数值仿真表明当圆光栅出现端面定位安装误差后,回转轴回转一周,输出的莫尔条纹光强变化经历了一个周期,近似为一正弦曲线。针对上述理论分析,在加工中心回转轴C轴上进行了实验研究,结果表明,通过调整圆光栅端面的跳动误差从原来的70μm到16μm,利用高精密单频激光干涉仪对回转轴的定位误差进行了检测,两次测量的定位误差曲线均为正弦曲线,且回转轴的定位精度提高了3倍。研究结果表明,减小圆光栅定位端面的轴向跳动误差可有效提高回转轴的定位精度。
In order to solve the problem of the poor positioning accuracy of rotary axis affected by the installation error of circular grating-the key measuring element of fully-closed-loop NC rotary axis,based on the operating principle of angle measurement with circular grating,the influence law of moire fringe affected by the run-out of positioning end face of grating during the installation was analyzed thoroughly,a cooresponding mathematic relationship was deduced and a mathematical model between rotary axis positioning error and run-out error of positioning end face of grating was established as well.Numerical simulation shows that once the installation error of positioning end face of circular grating occurs,the output light intensity varation of moire fringe goes through a cycle,which approximats a sine curve.Adjusting the former run-out error value of end face of circular grating from 70 μm to 16 μm,the positioning error of rotary axis was measured with high precision single frequency laser interferometer,the error curves of measuring results were both sine curves and the positioning accuracy was incresed 3 times over before.So correctness of the theoretical analysis was verified.At the same time,the experimental results indicate that reducing the axial run-out error of positioning end face of circular grating can improve the positioning accuracy of rotary axis effectively.
出处
《机电工程》
CAS
2013年第12期1481-1484,共4页
Journal of Mechanical & Electrical Engineering
基金
国家科技重大专项资助项目(2013ZX04001081)
关键词
定位精度
圆光栅
端面跳动
误差分析
positioning accuracy
circle grating
end face run-out
error analysis
