| Active phased array radar is the "clairvoyant" in modern war,and it is the core equipment to realize battlefield perception and long-distance precision strike.With the improvement of radar detection range requirements and mobility requirements,the active phased array radar array is developing in the direction of large-scale and lightweight.The structural stiffness of the antenna array is limited,and it is more prone to dynamic structural deformation under the influence of complex environmental loads,resulting in the deterioration of the electrical performance of the antenna.In order to ensure the electrical performance of service antenna,the real-time and accurate sensing of antenna array structure state is the prerequisite.Therefore,focusing on the problem that it is difficult to reconstruct the large active phased array antenna array surface with high accuracy,this paper determines the method of shape reconstruction,analyzes the influence mechanism of reconstruction accuracy,proposes a high-precision hybrid reconstruction method,develops a software platform and applies it to the actual antenna array model.The main work of this thesis is as follows:(1)The shape reconstruction method for a large active phased array antenna array model is determined.Three typical structural deformation reconstruction methods are used for simulation and comparison.The results show that compared with Ko displacement theory which is only suitable for typical simple beam structure,inverse finite element method is difficult to construct element shape function suitable for complex structure.Modal method can construct strain displacement conversion matrix by extracting modal information on the basis of modal analysis of finite element model,which can be well applied to static analysis Finally,modal method is used to reconstruct the shape of large array,which lays a theoretical foundation for the real-time reconstruction of antenna structure.(2)The theoretical model of modal method and the actual service condition of antenna are analyzed,and the influence mechanism of reconstruction accuracy is studied.Because the modal method relies on the accuracy of the finite element model,the deviation between the finite element model and the actual model is the core factor affecting the reconstruction accuracy.In order to analyze the influence of the actual service conditions on the reconstruction accuracy,the experimental platform is built through the strain measurement system and the displacement measurement system,and it is found that the sensor reading will be affected by the temperature,resulting in the drift of the reconstruction accuracy.In addition,the experimental platform also provides support for the improvement of reconstruction accuracy.(3)A hybrid reconstruction method based on modal method and error calibration model is proposed.Aiming at the modeling error of finite element model,a structural modal characteristic parameter correction method based on least square method is proposed to ensure the accuracy of the strain displacement conversion matrix;for the reading drift of strain sensor,the temperature compensation is applied to the sensor and the comprehensive data filtering method based on de extremum and recursive average is used to filter the data to ensure the reliability and accuracy of the strain data Stability.The experimental results show that the reconstruction accuracy of this method is more than 85% and the calculation time is better than 50 ms compared with the actual element displacement in the maximum deformation direction obtained by photogrammetry.Based on the electromechanical coupling model,the influence of the reconstructed structure deformation on the electrical performance is analyzed.The results show that the deflection error of the antenna beam is within 0.05 degrees.(4)An online monitoring software platform of antenna array deformation based on C #language is developed.By using socket network communication and multithreading technology,the interactive requirements between the software platform and MATLAB hybrid reconstruction program are met through the way of dynamic link library.The strain collection of key points of array,the reconstruction calculation of array shape and the realtime three-dimensional display of array structure state are realized,which provides support for the real-time control of antenna electrical performance and proves the engineering application value of this method... |
PDF Full Text Request