Optical Path Scanning Control System Based on Repetitive Control and PI Control

In order to obtain fine spectra with high resolution and accuracy, the large optical path difference and the stable optical path reciprocal scanning modulation are necessary in a spectrum detection system. According to scanning characteristics, a mathematical model of the permanent magnet synchronous motor is established. Considering the long path length, rapid commutation, and high speed stability, this paper develops a speed feedback loop and a position feedback loop with PI controller. As the PI controller produces periodic error when tracking periodic signals and reduces the rate stability, a modified repetitive control (MRC) method is studied. The simulation results show that the proposed method can achieve uniform scanning of the optical path difference, and has a good ability to suppress sliding friction.