基于参数估计的精密离心机回转轴线测量方法

Rotation axis measurement method for precision centrifuge based on parameter estimation

回转轴线的确定作为10-6量级精密离心机静态工作半径校准的重要步骤,其准确性将直接影响输出加速度的测量不确定度。根据定义,回转轴线作为虚拟基准,无法通过测量直接得到。针对上述问题,通过高斯滤波、偏心量及倾斜量参数估计、自动化调整,提出了一种基于参数估计的精密离心机回转轴线测量方法,可实现标准圆柱棒几何中心线与回转轴线重合,达到基准转换的目的。利用圆度仪及模拟仿真、验证了滤波算法与参数估计的正确性及有效性;利用精密转台、标准圆柱棒、光谱共焦传感器、六轴并联定位运动平台搭建了回转轴线测量单元。试验结果表明,标准圆柱棒与回转轴线的偏心量可调整至0.2μm,倾斜量可调整至0.0002°。

As an important step to calibrate the static working radius of a 10-6 scale precision centrifuge,the accuracy of the rotation axis determination will directly affect the measurement uncertainty of the output acceleration.According to the definition,the rotation axis used as a virtual datum cannot be directly obtained with measurement.Aiming at the above problems,a measurement method for the rotation axis of precision centrifuge based on parameter estimation is proposed using Gaussian filtering,eccentricity and tilt parameter estimation,and automatic adjustment.The method can make the geometric center line of standard cylinder rod coincide with the rotation axis,and achieves the purpose of datum conversion.Roundness meter and emulation experiments were used to verify the correctness and effectiveness of the filtering algorithm and the parameter estimation.A rotation axis measurement unit was built using precision turntable,standard cylinder rod,spectral confocal sensor and six axis parallel positioning motion platform.The test results demonstrate that the eccentricity between the standard cylinder rod and the rotation axis can be adjusted to 0.2μm,and the tilt can also be adjusted to 0.0002°.