Research On Models And Applications Of Dynamic Deformation Monitoring Based On MEMS IMU

Dynamic deformation monitoring is not only an important guarantee for the maintenance and safe operation of large engineering structures,but also an important premise for timely diagnosis and early warning of structural abnormalities.However,the dynamic deformation monitoring of large-scale engineering structures still has insufficient completeness and accuracy of feature parameter extraction.In this paper,the high dynamic deformation monitoring model and application of MEMS IMU are studied in detail and systematically,including the deformation monitoring data reconstruction method based on variational mode,vmd-hht dynamic deformation feature extraction model,GNSS assisted accelerometer frequency domain integration algorithm,correlation analysis of displacement deformation to torsional deformation,torsional deformation monitoring model based on Mahony complementary filter,etc,The main research results are as follows:(1)Aiming at the problem that the identification standard of effective modal component of variational modal decomposition is incomplete,the Flandrin criterion is introduced,and the adaptive separation model between dynamic deformation data and observation noise is established to realize the synchronous elimination of low-frequency trend term and high-frequency noise of dynamic deformation data.(2)Aiming at the problem that the existing feature extraction methods can not accurately extract the complete time-frequency features,a new time-frequency energy multi-dimensional feature extraction method(VMD-HHT)combining variational modal decomposition(VMD)and Hilbert Huang transform(HHT)is proposed.The frequency component of vibration events is extracted by VMD,the noise component is filtered,and the extracted vibration signal is transformed by HHT,The time frequency energy multi-dimensional deformation feature extraction of vibration monitoring data is realized,and the accuracy and completeness of deformation feature extraction are improved.(3)Aiming at the problem of uncertain initial position of accelerometer frequency domain integration,a GNSS assisted accelerometer frequency domain integration method is proposed.The sliding window is used to assign GNSS initial position information to the monitoring data in a period of time,which improves the absolute accuracy of engineering structure dynamic displacement monitoring.(4)In view of the fact that the current dynamic deformation monitoring only monitors the deformation displacement and ignores the influence of torsional deformation on engineering structures,a torsional deformation monitoring model based on Mahony complementary filter is established,the internal influence of torsional deformation on engineering structures is analyzed,the coupling relationship between attitude deformation and displacement deformation is revealed,and the synchronous monitoring of high-frequency position and attitude parameters is realized.(5)Facing the research on the environmental impact and dynamic deformation monitoring of the Great Wall,the influence of wind load and ground traffic vibration on the enemy station of the Great Wall is analyzed.Based on vmd-hht model,the instantaneous vibration frequency and energy generated by two influence factors on the great wall are extracted.The above research can provide an important reference for the real-time safety monitoring and protection of the Great Wall.