Research On Suspension Of Test Mass In Inertial Sensor Based On Roberts Linkage Mechanism

High precision inertial sensors are important tools in the process of space exploration.Due to the high risk of space experiments,they need to be experimentally researched on the ground in advance to verify their function and performance.At present,there are three types of ground research methods for inertial sensors to overcome the influence of gravity acceleration,and one of them is a fiber suspension test mass scheme.Our research group has designed a fiber suspension test mass scheme based on a two-stage pendulum.This scheme can test the two-degree-of-freedom performance of translation and rotation for test mass.From the perspective of achieving cross-coupling test of two translational degrees of freedom measurement of test mass,we can consider using a special linkage mechanism to suspend test mass.Among them,the Roberts Linkage Mechanism is a typical model that generates approximate straight lines,and it has a simple structure,which can build a stable two-dimensional model and achieve a long motion cycle.Therefore researching on suspension of test mass in inertial sensor based on Roberts Linkage Mechanism is of great significance for the testing of multiple degrees of freedom performance of test mass.This dissertation introduces the basic structure of the Roberts Linkage and analyzes the working principle of applying it to the ground test of the inertial sensor to verify the test mass suspension.In order to evaluate the influence of Roberts Linkage Mechanism on test mass,firstly,the linear characteristics of the Roberts link mechanism are theoretically analyzed,and the trajectory equation of the suspension point of quality is obtained and compared with the numerical results.At the same time,this paper also analyzes the position of the center of mass of the linkage mechanism,the suspension of the suspension wire bending and the suspension wire inclination generated by the link mechanism during the swing process,the system transfer function is finally obtained.The motion cycle of the system is known by its transfer function,and the influence of various parameters on the motion cycle of the system is analyzed.Secondly,the performance of the system is analyzed.From the analysis of the stability of the system,the maximum position at which the center of mass can be raised is calculated.From the analysis of the installation requirements of the system,the maximum allowable installation error range of the system is calculated.when testing the inertial sensor on the ground,it will be affected by the thermal noise of the suspension wire and the vibration of the ground.Theoretical calculations are made for the influence of suspension thermal noise and ground vibration.Finally,specific model is selected and parameters are selected.In the process of parameter selection,a set of analysis methods and design principles are established.The specific parameters are substituted into the transfer function and the transfer function image is drawn.