基于激光干涉仪对天文底片扫描仪气浮式运动平台的性能测试

Performance test of the air-bearing motion platform applied by the astronomical plates digitizer based on the laser interferometer

摘要:

为推进国际天文底片数字化工作，上海天文台正在开展高精度天文底片专用扫描仪的研制。两轴线性运动平台是高精度天文底片扫描仪的核心部件，需要对其各项参数进行标准化测试，以获取其对天文底片数字化精度的直接影响。基于激光干涉测量原理，使用RENISHAW XL80激光干涉仪搭建测量光路，对正在研制的天文底片扫描仪所用气浮式运动平台关键性能进行了测试。结果表明，在350mm×350mm工作范围内，气浮式运动平台载物台的定位重复精度优于0.025μm，直线度和平面度优于0.3μm，俯仰角和偏摆角误差小于0.3″。该平台满足高精度天文底片扫描仪设备的研制需求，测试结果不仅可为扫描仪设备的整体性能评估提供参考，也可为后续的位置系统差补偿提供依据。

Abstract:

In order to promote the international digitization of astronomical plates, Shanghai Observatory is developing a special high-precision digitizer for astronomical plates. The two-axis linear motion platform is the core component of the high-precision astronomical plates digitizer, and its parameters need to be tested to obtain its direct influence on the accuracy of digitization of astronomical plates. Based on the principle of laser interferometry, the optical path for measurement is built by using RENISHAW XL80 laser interferometer. The key performance of the air-bearing platform for the astronomical plate digitizer which is being developed by Shanghai Astronomical Observatory is tested. Results show that the positioning repeatability of the stage fixed on the air-bearing motion platform is better than 0.025μm, the straightness and flatness are both better than 0.3μm, and the attitude errors including pitch and yaw are less than 0.3″. The air-bearing motion platform can meet the development requirement for high-precision digitization equipment to digitize astronomical plates. The results can offer a reference for the overall performance evaluation of the digitizer and provide a basis subsequently for compensating systematic positioning error.