Research On Spatial Truss Structure Morphology Monitoring Technology Based On Distributed Optical Fiber Sensing Technology

Space truss structure is a large flexible space structure with complex dynamic characteristics such as low frequency,dense mode and non-linearity.With the development of space industry,more and more missions are undertaken by spacecraft,and the structure of spacecraft is developing towards largescale and complex direction.Intelligent identification of service state of such structure is of great significance to the design of new space truss and the research of high orbit deep space exploration.In this paper,a shape monitoring technology of space truss structure based on distributed optical fiber sensing technology is proposed.An error correction method for space truss structure monitoring is proposed,and a continuous method for multi-segment splicing structure is given.The main contents of this paper include the following aspects:Firstly,the complex space truss structure is decomposed and simplified,and the distributed optical fiber sensor is selected as the sensing element.The recursive curvature deformation algorithm based on curvature and arc length information and the KO displacement deformation algorithm based on deflection information are studied.With the help of ANSYS Workbench finite element analysis software,numerical simulation and shape reconstruction of similar space truss structures are carried out.The overall strain distribution and deformation characteristics of beam and front structures under different constraints and loading conditions are obtained by numerical simulation.Secondly,the path strain and displacement information of beam and front structure under different constraints and loading conditions in numerical simulation environment are selected.Based on KO displacement deformation algorithm and curvature recurrence algorithm,the deformation results of beam and array structures under different constraints and loading conditions are calculated and compared with the simulation results,which provides an algorithm basis for the Deformation Inversion experiment of spatial truss distributed optical fiber sensing.Thirdly,the deformation monitoring and inversion techniques of beam and array structures under different constraints and loading conditions based on distributed optical fiber sensing technology are studied.Based on the graphical software LabVIEW,three-dimensional structural morphology monitoring and visualization are realized:(1)shape monitoring and reconstruction under the condition of single-ended and double-ended fixed-supported beam structures;(2)static pure bending deformation and static torsion deformation of single-ended fixed-supported array structures and their visualization;(3)shape monitoring,inversion and visualization of static deformation of double-ended fixed-supported array structures.The validity of the deformation reconstruction method is verified by comparing the measured values of laser displacement sensor with the results of deformation algorithm.Then,aiming at the deformation monitoring requirements of continuous multi-segment structure and discontinuous multi-segment structure in space truss structure,based on geometric coordinate transformation method,a method of continuous deformation form for continuous multi-segment structure and discontinuous multi-segment structure is studied,and the continuation of continuous and discontinuous multi-segment spliced beam structure and array structure is realized by simulation.Finally,aiming at the error correction requirement of space truss deformation inversion,the error sources of space truss structure deformation monitoring and inversion system are analyzed,and an error correction method based on error correction library is proposed.On this basis,numerical simulation and experimental verification are carried out to verify the corrective effect of the deformation error of the beam structure based on this method.