System for simultaneously measuring 6DOF geometric motion errors using a polarization maintaining fiber-coupled dual-frequency laser

Abstract

A novel method for simultaneously measuring six degree-of-freedom (6DOF) geometric motion errors is proposed in this paper, and the corresponding measurement instrument is developed. Simultaneous measurement of 6DOF geometric motion errors using a polarization maintaining fiber-coupled dual-frequency laser is accomplished for the first time to the best of the authors' knowledge. Dual-frequency laser beams that are orthogonally linear polarized were adopted as the measuring datum. Positioning error measurement was achieved by heterodyne interferometry, and other 5DOF geometric motion errors were obtained by fiber collimation measurement. A series of experiments was performed to verify the effectiveness of the developed instrument. The experimental results showed that the stability and accuracy of the positioning error measurement are 31.1 nm and 0.5 μm, respectively. For the straightness error measurements, the stability and resolution are 60 and 40 nm, respectively, and the maximum deviation of repeatability is ± 0.15 μm in the x direction and ± 0.1 μm in the y direction. For pitch and yaw measurements, the stabilities are 0.03″ and 0.04″, the maximum deviations of repeatability are ± 0.18″ and ± 0.24″, and the accuracies are 0.4″ and 0.35″, respectively. The stability and resolution of roll measurement are 0.29″ and 0.2″, respectively, and the accuracy is 0.6″.

Grating-Corner-Cube-Based Roll Angle Sensor

“…Several non-contact roll angle measurement methods have been reported, including the polarization–modulation method [ 8 , 9 , 10 ], interference method [ 11 , 12 , 13 , 14 , 15 ], and differential position measurement method [ 16 , 17 , 18 , 19 , 20 , 21 ]. The principle behind the polarization–modulation method involves the modulation of the polarization state of the measurement beam through roll angle variation, wherein the roll angle can be calculated based on intensity measurements.…”

“…The generation of two beams for differential detection is a critical aspect of this method. In general, as two corner cubes are used as a combined target, the installation of these cubes is necessary, with the requirement for a large base to fix the targets, which encumbers the system [ 17 ]. In addition, the measurement accuracy of the roll angle is easily affected by the crosstalk error of the other degrees of freedom and the installation error of the two corner cubes [ 18 ].…”

Embedded Sensor System for Five-degree-of-freedom Error Detection on Machine Tools

“…Liu [9] developed a 3-beam 6-DOF system based on fiber coupled laser interferometer. Feng and Cui [10][11][12][13] et al developed a series of 2-beam 6-DOF measurement system. Huang [17] developed a 2-beam 5-DOF measurement system based on a monolithic prism to generate a pair of parallel laser beam.…”

Design of a Measurement System for Simultaneously Measuring Six-Degree-Of-Freedom Geometric Errors of a Long Linear Stage

“…At present, for multi-axis machine tools, linear precision stages are the key components, and have been widely used as the basis for linear motion, and constrain its motion to a desired direction or posture [ 6 , 7 ]. However, due to the deviations caused by manufacturing imperfections, assembly, misalignments, structural deflections and so on, a linear precision stage will inherently have six-degree-of-freedom (6DOF) geometric motion errors, including three linear errors (positioning error δ x , horizontal straightness error δ y , and vertical straightness error δ z ) and three angular errors (pitch error ε y , yaw error ε z , and roll error ε x ) [ 8 , 9 ]. As a result, in order to improve the accuracy and repeatability of the multi-axis machine tools, 6DOF geometric motion errors of the linear precision stage should be accurately identified and effectively compensated [ 10 , 11 ].…”