Micro-Nano Combined Non-Contact Measurement Technology

The Fiber-optic sensor has many advantages such as simple structure, strong anti-interference, non-contact measurement, etc. It can be combined or arrayed to achieve multi-point, distributed measurement, which has good prospects for development in the on-line measurement, multi-dimensional measurement and other areas.This paper presented a new, high-efficiency, high-precision flatness measurement solution based on the Fiber-optic. Without relying on mechanical probe, the solution could achieve a wide range to high-speed measurement, which could improve the measurement speed, accuracy and reliability. The following work was completed in this thesis:1. RIM-FODS which had the structure of the dual concentric circles was applied: compared with other structure, the structure of the dual concentric circles could eliminate the effect of light source intensity fluctuations and the measured surface roughness, improve the measurement accuracy. Based on this type of sensor, the overall system was designed.2. The circuit of signal processing and data acquisition was introduced in detail, which included light modulation circuit, preamplifier, band-pass filter circuit, AD conversion circuit and so on; To ensure measurement accuracy and reduce interference, the technologies or tools were taken in this thesis, which include DDS technology, modulation technology, band-pass filtering technology;3. The software design tasks were completed, which included hardware control program of each module and algorithm for evaluating flatness; Display and interactive functions were achieved;4. Experimental platform was built. According to the experimental data, the output characteristic curve were completed, which was calibrated; Linearity and error of curve were analyzed in detail; Some circuit experiments for system characteristics were carried out; Repeatability, stability and other performance indicators were analyzed in detail; The.experiment results showed that the maximum repeatability error of the system was 4mV, the maximum linearity error was 1.2% and sensitivity was more than 1.7mV/μm. Compared with the measurements of CMM, the correctness of the program was verified.