原位测量是提高光学自由曲面面形精度的重要手段, 对于提高加工效率、实现加工过程自动化具有重要意义。由于面形的复杂性, 光学自由曲面原位测量一直是超精密测量领域的难题。提出了一种基于超精密机床的光学自由曲面原位测量方法, 测量系统由LVDT气浮式传感器、红宝石探针和数据采集部件组成, 采用螺旋线方式进行加工及测量路径的设计, 通过运动控制接口实现机床坐标和测量数据的实时同步采集, 快速精确地获取测量数据。实验结果表明, 所加工的双正弦自由曲面的面形误差在±0.5μm范围内。

The in-situ measurement is an important means to improve the form accuracy of optical free-form surface, because it can improve the machining efficiency and realize process automation. It is difficult to conduct the in-situ measurement for optical free-form surfaces due to the shape complexity. An in-situ measurement method for optical free-form surfaces is presented based on ultra-precision machine. The measuring system is composed of LVDT air-bearing sensor, ruby probe and data acquisition card. The measuring processing is carried out according to the spiral path strategy. The synchronous acquisition of machine tool positions is realized based on the motion control interface, measurement result can be obtained rapidly and accurately. The experiment result shows that the form error of double sine free-form surface is less than ±0.5μm.