Research On High-precision Optical Fiber Sensing Mechanism Of Scraper Conveyor Shape In Intelligent Working Face

In the process of intelligent construction of coal mines,high-precision perception of the shape curve of scraper conveyors is crucial for intelligent working faces to achieve adaptive coal cutting by shearers,and adaptive movement of scraper conveyors and hydraulic supports.The current mainstream technology is based on strapdown inertial navigation to achieve path inversion of shearers,which guides the adaptive movement of scraper conveyors in working faces.However,there are indirect errors and hysteresis in the inversion of the curve of the scraper conveyor based on the dotted line of strapdown inertial navigation,which cannot guide the real-time dynamic control of the scraper conveyor and the hydraulic support in the working face.In recent years,large-scale fiber grating shape sensors have been used for shape sensing of scraper conveyors,achieving real-time curvature sensing,but there is still room for improvement in accuracy.In this thesis,accuracy compensation models are constructed for various error sources,and the accuracy and reliability of the theoretical model are verified through simulation and experiments.The following findings were made:(1)Based on the field application of fiber grating shape sensors for scraper conveyors,this thesis analyzes the main error sources during long-term operation,and introduces the concepts of rotation error angle and torsion error angle.Based on the principle of fiber Bragg grating sensing,the mathematical relationship between sensor curvature,wavelength drift,and rotation error angle is derived,and a curvature accuracy compensation model based on rotation error angle is constructed;At the same time,by analyzing the torsion microsegment of the sensor,the torsion strain equation of the surface mounted grating string is established,and the theoretical relationship between the sensor curvature,wavelength drift,and torsion error angle is derived.A curvature accuracy compensation model based on the torsion error angle is constructed.(2)The ANSYS Workbench numerical simulation was used to validate the rotation error angle accuracy compensation model and the torsion error angle accuracy compensation model,respectively.The center strain values of orthogonal arranged fiber Bragg grating strings were derived under specific curvature,and the results showed that the simulated strain values were basically consistent with the theoretical strain values.The relative strain errors after generating the rotation error angle are all within ± 0.6%,The relative errors of the strain after generating the torsion error angle are all within ± 8.2%.After curvature compensation based on simulated strain,the curvature radius is calculated back.The relative errors of the curvature radius of the rotation error angle are all within ± 0.9%,and the relative errors of the curvature radius of the torsion error angle are all within ± 4.6%.The accuracy compensation model has been validated through numerical simulation methods.(3)The experimental research on rotation error angle and torsion error angle was carried out through the self-developed experimental platform for curvature error response characteristics of fiber grating shape sensors for scraper conveyors.Experimental studies on the rotation error angle of sensing substrates with rotation error angles of 0°,30°,and 45° were conducted.After compensation,the absolute error was significantly reduced compared to before compensation,and the end accuracy of the reconstructed curve was improved by 6.78% and 14.46%,respectively,compared to before compensation.Experimental research on the torsion error angle of sensing substrates with torsion error angles of 0°,10°,and 20° was conducted.After compensation,the absolute error decreased compared to before compensation,and the end accuracy of the reconstructed curve increased by 2.77% and 1.93% compared to before compensation.Experiments have verified that the accuracy compensation model proposed in this thesis can effectively improve the end accuracy of the scraper conveyor during shape reconstruction,which provides higher accuracy data support for actions such as adaptive straightening of the scraper conveyor in intelligent working faces.This thesis has 49 charts,13 tables,and 98 references.