Chuang Sun

A compact laser collimation system is presented for the simultaneous measurement of five-degree-of-freedom motion errors. The optical configuration of the proposed system is designed, and the principle of the measurement of five-degree-of-freedom errors is described in detail. The resolution of the roll and the horizontal straightness is doubled compared with other laser collimation methods. A common optical path compensation method is provided to detect light drift in real time and compensate for straightness and angle errors. An experimental setup is constructed, and a series of experiments are performed to verify the feasibility and stability of the system. Compared with commercial instruments, the pitch and yaw residuals are ${\pm 2.5}^{″}$ and ${\pm 3.5}^{″}$ without correction, and the residuals are ${\pm 1.9}^{″}$ and ${\pm 2.8}^{″}$ after correction, respectively. The comparison deviations of the horizontal straightness and vertical straightness changed from $\pm 4.8 \mathsf{\mu }$ m to $\pm 2.8$ μm and $\pm 5.9$ μm to $\pm 3.6$ μm, respectively. The comparison deviation of the roll is ${\pm 4.3}^{″}$ . The experimental results show that the data of the five-degree-of-freedom measurement system obtained are largely the same as the measurement data of commercial instruments. The common optical path compensation can effectively improve the measurement accuracy of the system.