球面惯性元件激光共焦曲率半径测量系统

In view of the difficulty and low accuracy in measuring the radius of curvature caused by the scattering characteristics of spherical inertial elements, a laser confocal radius measurement system for spherical inertial elements is developed. The system uses pinhole filter to reduce the proportion of the scattered light received by the detector to restrain the influence of scattered light. Confocal feedback technology is used to improve the detection intensity of returned light to adapt the detection of spherical inertial elements with low reflectivity. The peak point of the confocal axial response curve corresponds to the focus of objective lens. According to this characteristic, the cat's eye position and the confocal position of the measured elements is precisely positioned, and the distance between the two points is obtained by a distance measurement interferometer, then the radius can be measured accurately. The experiment is conducted with hemispherical gas-dynamic bearing as the experimental object. The theoretical analysis and experimental results show that the relative expanded uncertainty of the system is better than 20×10^-6, and the proposed measurement system provides a technical approach for high-precision measurement of curvature radius of spherical inertial elements with scattering characteristics.