坐标测量机动力学刚度估计与加速度误差补偿

Estimating Dynamic Stiffness of Coordinate Measuring Machine for Compensation of Acceleration Error

提出了用于坐标测量机(CMM)加速度误差补偿的气浮导轨的刚度和阻尼的估计方法.利用CMM框架模型建立振动方程,并转化为包含刚度和阻尼参数的惯性系统的频响函数形式.通过试验测试了CMM系统的加速度频率响应,由相应的Bode图而非Levy法估算了CMM气浮导轨的刚度与阻尼,对参数辨识后的CMM系统进行模态分析,从而得到了采用模态叠加法的加速度误差补偿模型.试验表明,用该方法进行的加速度误差补偿,CMM测端处误差预测值与实测值的相关系数大于0.7,证明了该方法的可靠性.

A method to estimate the stiffness and damping of the aerostatics slideways of coordinate measuring machine （CMM） for the compensation of acceleration errors is proposed. The vibration equations of CMM are established from the framework model of CMM and transformed into the form of the frequency response functions （FRFs） of first order systems, where the identified parameters are contained. The FRFs are tested and then the stiffness and damping parameters can be identified with Bode diagram rather than Levy method. Modal analysis is performed on CMM system after the identification of stiffness and damping parameters. The acceleration er- rors are forecasted with modal superposition method. Experiments indicate that the cross-correlation coefficient between the measured errors and the forecasted errors at CMM probe tip is over 0. 7, which verifies the effectiveness and reliability of the proposed method.