Vibration Analysis And Optimization Design Of Optical Mounting Frame For Coal Quality On-line Detection

The on-line detection of coal quality uses laser-induced breakdown spectroscopy.The optical adjustment frame is the bearing component of the optical component in the laser transmission optical system.The interference of the optical adjustment frame by vibration causes the laser beam to shift in a complex working environment.It leads to poor laser quality on coal samples to be tested,and then affects the accuracy of spectral analysis results of coal quality detection.Analyze the influence of vibration environment on the optical adjustment frame in Laser Induced Breakdown Spectroscopy system,and clarify the relationship between the performance of the optical adjustment frame in the coal quality on-line detection system and the laser beam quality during the working process.According to the functional requirements of the optical mount,the overall scheme design is carried out.The functional requirements and main technical indicators of the four-dimensional transformation adjustment and two-dimensional displacement adjustment are realized according to the optical adjustment frame.The components are divided into two subsystems-the support system and the adjustment system according to the optical The functional design structure schematic diagram of the adjustment frame,on the basis of which the structural design of the optical adjustment frame is completed.Establishing the laser beam transmission model in the vibration environment provides a theoretical basis for the calculation of the vibration imbalance of the optical system,and lays a good foundation for the simulation analysis of the optical adjustment frame.The finite element dynamics model of the optical mount was established for modal analysis and random vibration analysis.Through the modal analysis,the first 6 natural frequencies and vibration modes are obtained,and the mode types of each order are analyzed.The numerical axis with the largest effective mass participating in the calculation is selected for random vibration analysis by comparing concentrated mass according to the results of modal analysis,so the corresponding stress-strain cloud diagram is obtained.On the basis of random vibration,a point on the mirror base of key components is extracted for the displacement power spectral density response analysis.When the frequency exceeds 900 Hz,the displacement change rate sharply increases,and the maximum PSD response value is2.823E-04 mm~2/Hz.In order to enable the optical mount to transmit the laser beam in a vibrating environment and ensure the stability of the beam,by changing the design variables such as the thickness of the support member and the rear mirror plate,the optical mount has better stress and strain values under dynamic conditions.Design Exploration,an integrated module of structural optimization in ANSYS Workbench software,was used in this paper to carry out multi-objective optimization design for the support parts of the optical adjustment stand and the rear mirror seat plate based on the response surface method,and to analyze the variation trend and sensitivity of various variables.By using direct optimization method,the optimization results are obtained and compared with the dynamic analysis results before and after optimization.