Compact Laser Collimation System for Simultaneous Measurement of Five-Degree-of-Freedom Motion Errors

• Main Authors: Chuang Sun, Sheng Cai, Yusheng Liu, Yanfeng Qiao
• Format: Article
• Language: English
• Published: MDPI AG 2020-07-01
• Series: Applied Sciences
• Subjects: 5DOF motion errors; laser collimation; common optical path
• Online Access: https://www.mdpi.com/2076-3417/10/15/5057

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 <inline-formula> <math display="inline"> <semantics> <mrow> <msup> <mrow> <mo>±</mo> <mn>2.5</mn> </mrow> <mrow> <mo>″</mo> </mrow> </msup> </mrow> </semantics> </math> </inline-formula> and <inline-formula> <math display="inline"> <semantics> <mrow> <msup> <mrow> <mo>±</mo> <mn>3.5</mn> </mrow> <mrow> <mo>″</mo> </mrow> </msup> </mrow> </semantics> </math> </inline-formula> without correction, and the residuals are <inline-formula> <math display="inline"> <semantics> <mrow> <msup> <mrow> <mo>±</mo> <mn>1.9</mn> </mrow> <mrow> <mo>″</mo> </mrow> </msup> </mrow> </semantics> </math> </inline-formula> and <inline-formula> <math display="inline"> <semantics> <mrow> <msup> <mrow> <mo>±</mo> <mn>2.8</mn> </mrow> <mrow> <mo>″</mo> </mrow> </msup> </mrow> </semantics> </math> </inline-formula> after correction, respectively. The comparison deviations of the horizontal straightness and vertical straightness changed from <inline-formula> <math display="inline"> <semantics> <mrow> <mo>±</mo> <mn>4.8</mn> <mo> </mo> <mi mathvariant="sans-serif">μ</mi> </mrow> </semantics> </math> </inline-formula>m to <inline-formula> <math display="inline"> <semantics> <mrow> <mo>±</mo> <mn>2.8</mn> </mrow> </semantics> </math> </inline-formula> μm and <inline-formula> <math display="inline"> <semantics> <mrow> <mo>±</mo> <mn>5.9</mn> </mrow> </semantics> </math> </inline-formula> μm to <inline-formula> <math display="inline"> <semantics> <mrow> <mo>±</mo> <mn>3.6</mn> </mrow> </semantics> </math> </inline-formula> μm, respectively. The comparison deviation of the roll is <inline-formula> <math display="inline"> <semantics> <mrow> <msup> <mrow> <mo>±</mo> <mn>4.3</mn> </mrow> <mrow> <mo>″</mo> </mrow> </msup> </mrow> </semantics> </math> </inline-formula>. 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.