Research On Analysis And Suppression Of Interference Modal Of Gravity Gradiometer Based On Flexure-strip Suspension

Gravity gradient measurement has very broad application prospects in resource exploration,disaster warning,and gravity-assisted navigation.In view of the low measurement efficiency and poor stability of the E(?)tv(?)s torsion balance gravity gradiometer,our research group has proposed a solution to replace the suspended wire with a flexure-strip.In this paper,aiming at the interference modal problem in the development process of the principle prototype of the gravity gradiometer based on flexure-strip suspension,the interference modal is theoretically modeled,and the characteristics of the modal signal detected by the system are given.the control strategy of the interference modal is discussed,and the control through simulation is realized,which suppresses the vibration of the interference modal.First of all,the principle of the gravity gradiometer based on flexure-strip suspension is introduced,and the interference modal problem in the prototype development process is described,the source of the interference modal is analyzed in detail,and its influence on the measurement is discussed.Through theoretical modeling of the interference modal,an analytical solution satisfying its frequency is given,and the correctness of the analytical solution is verified.Combined with the modeling process,the transfer function of the interference modal signal detected by the system is further established.Secondly,in order to suppress the influence of the interference modal on the measurement,the control strategy is analyzed,and the upper and lower test mass combination control pattern is proposed.Using the principle of combined measurement,a system simulation control platform is established based on Simulink,which realizes the control of the interference modal signal measured by the experiment.The control results show that the combined pattern of upper and lower test mass can effectively suppress the influence of the vibration of the interference modal on the measurement resolution of the system.Finally,a parameter design process with interference modal frequency signals is established,and the parameters of the gravity gradiometer based on flexure-strip suspension under the combined measurement pattern of upper and lower test mass are analyzed,and the mechanical part parameters and assembly circuit parameters are given,which provides preliminary design parameters for subsequent experimental research.