High precision real-time measurement method for micro Six-Degree-of-Freedom motion

The high precision real-time measurement method for micro six-degree-of-freedom (6-DOF) motion plays an important role in the measurement scenes such as high frequency shaking table and precision displacement table, which require real-time measurement and accuracy. Based on the working principle of the laser rangefinder, the complex spatial motion measurement is reduced to the two-dimensional planar motion of the spot emitted by laser rangefinder in the Position Sensitive Detector (PSD) plane and the linear motion of the laser spot. The corresponding decoupling measurement model is established according to the physical position relationship between the laser rangefinder and the PSD. Compared with the traditional 6-DOF motion measurement methods, the decoupling measurement model of the micro-6-DOF motion high-precision real-time measurement method has low complexity, wide operating frequency range, and can meet the requirements of long-distance measurement while obtaining high accuracy measurement results. Based on the high sampling rate of the measuring instrument, this method can effectively meet the real-time measurement requirements. The simulation experiment results show that when the process noise is large, the motion information measurement accuracy of the Stewart platform in different motion forms is within the range of 10^-3mm in terms of displacement (mm) and 10^-2mrad in terms of rotation (sub-mrad). The phase accuracy is within the range of 10^-1mrad. The experimental results verify the proposed method is feasibility, robustness and accuracy. The proposed method is of great significance for realizing high precision, real-time measurement for 6-DOF motion, which has the characteristics of micro, high frequency and remote.