Realization And Accuracy Optimization Of Echelle Grating Efficiency Detection Control System

As one of the most important components of the echelle spectrographs,the echelle grating has attracted much attention due to its high dispersion rate,high resolution,low scribe density and small volume.However,the diffraction efficiency and the stray light coefficient are the main technical indicators for measuring the echelle grating.The detection equipment and related literatures are rarely mentioned,which limits the development and application of the echelle grating and its spectrometer at a certain level.In order to realize the detection of diffraction efficiency and stray light coefficient,the control system is studied on the basis of the completion of the optical path design to optimize the detection accuracy.For the three-degree-of-freedom turntable equipped with the grating,when the stepping motor changes its position,there are situations such as inability to synchronize control,poor positioning accuracy,obvious vibration of the turntable,and high noise,so that the angle between the incident light and the grating deviates from the control target,moreover,under the long-term operation,the mechanical structure of the turntable is greatly damaged.Especially when the synchronous operation of three stepping motors is realized,the vibrations in the three directions are superimposed,and the influence on the positioning accuracy and the damage of the mechanical structure are even worse;For the stage with the photomultiplier tube,in the process of stray light acquisition,due to its low positioning accuracy,the same stray light coefficient should be obtained under the same conditions,but there is a large deviation,resulting in large repeatability error.In view of the above problems,this paper designs the fuzzy PID subdivision drive synchronous control of multi-stepping motor,the high-precision acquisition of stray light and the completion of the control system.Aiming at the low positioning accuracy,low-speed oscillation and high noise of the stepping motor,the fuzzy PID control algorithm is further improved under the premise that the subdivision drive improves the above characteristics.For the stray light coefficient repeatability error is high,the subdivision drive technology is used to control the stepper motor to achieve high-precision uniform velocity acquisition of stray light.For the development of the control system,the hardware design of the lower computer with STM32F103 as the microprocessor,the software design of the lower computer with ?C/OSIII as the embedded system and the design of the upper computer operating interface with C# programming language are completed.For the two-phase hybrid stepping motor,subdivision drive and fuzzy PID control,the control model is built and simulated on the MATLAB software Simulink platform.The model simulation shows that the stepper motor has no steady-state error,fast adjustment speed,reduced speed fluctuation and torque pulsation time and amplitude under the fuzzy PID subdivision drive control,which greatly improves the low-frequency oscillation and optimizes the positioning accuracy.Experiments were carried out on an optical platform,the experimental results show that the instrument has good control characteristics and optimizes the detection accuracy of the grating parameters.