Simultaneous Measurement And Compensation Of Six-degree-of-freedom Motion Error Of Moving Stages

Moving stage is the basis of precision manufacturing and measurement,the positioning accuracy of the moving stage directly affects the accuracy of manufacturing and measurement.Due to the processing and assembly errors,there are six-degree-of-freedom motion errors in the moving stage,including three angular errors(pitch error,yaw error and roll error),two straightness errors(horizontal straightness error and vertical straightness error)and positioning error.The positioning accuracy of the moving stage was affected by these motion errors.Therefore,it is necessary to accurately measure the motion errors and establish an appropriate error compensation model to improve the positioning accuracy.For the error measurement,the traditional method can not measure the multi-degree-of-freedom(DOF)errors at the same time.Moreover,the traditional measurement instrument is too bulky to integrate into the moving stage for the real-time error measurement.In addition,the traditional error compensation model is too complex and can not achieve the fast and on-line error compensation.Therefore,the simultaneous measurement of the multi-DOF motion errors and the establishment of a simple error compensation model are essential to improve the positioning accuracy of the moving stage.To address the problem for measuring the multi-DOF motion errors and establishing the error compensation model for the moving stage,a six-degree-of-freedom motion error measurement method is proposed in this paper.A motion error measurement system is designed.The measurement accuracy of horizontal and vertical straightness errors are ±0.30μm and ±0.15 μm,respectively.The measurement accuracy of pitch,yaw and roll errors are±2.00 arcsec,±1.80 arcsec and ±2.80 arcsec,respectively.And the measurement accuracy of positioning error is ±0.52 μm.The designed motion error measurement system is compact,which can be integrated into the moving stage for real-time error measurement.According to the structure of the moving stage,the error compensation model is established and optimized based on the Abbe principle and the Brian principle.The positioning accuracy of the moving stage is improved to be 1.30 μm after compensation from 18.73 μm before compensation,which is improved by 93.06%.