Research On High-precision Displacement Sensing Of Test Mass In Intertial Sensor Based On Principle Of Optical Lever

High-precision inertial sensors have important applications in space gravitational experiments and satellite gravity measurements.In the space gravitational wave detection plan,the detection of the displacement between the test mass?TM?and the spacecraft is one of the core tasks of the inertial sensor.The performance of the displacement sensing is very important for the high-precision inertial sensor.The displacement sensing methods commonly used in inertial sensors mainly include three displacement sensing:capacitive displacement sensing,displacement sensing based on superconducting quantum interference devices and optical displacement sensing.Among them,capacitive displacement sensing has the advantages of compact structure and high resolution,but it is susceptible to electromagnetic interference,and due to the need to introduce a modulated electric field,it will inevitably introduce interference caused by electrostatic force to the test mass;displacement sensing based on superconducting quantum interference devices requires a low temperature environment and is complicated,so it is inapplicable to space environment;displacement sensing based on optical principles generally has less environmental interference and minimal disturbance to TM.Optical lever has the advantages of simultaneous displacement measurement in six-degree-of-freedom?DOF?,large measuring range,simple operation and easy realization,which it is a potential displacement sensing measurement method.Therefore,it is of great significance to study displacement sensing based on the principle of optical leverage.In this paper,an optical sensing scheme based on optical lever is proposed for the multi DOFs displacement sensing requirements of high-precision inertial sensors.The function and performance of the optical sensing scheme are studied.Secondly,this paper analyzes the influence of the incident angle and the position of the light source and the photodetector on the sensing sensitivity,and optimizes the values of these parameters.Secondly,this paper analyzes the influence of the incident angle and the position of the light sources and the photodetectors on the sensing sensitivity,and optimizes the values of these parameters.Thirdly,this paper also investigates the types and performance of photodetectors and light sources,and analyzes the noise sources of TM in the 6 DOFs detection model.Finally,we use Simulink tool to verify the displacement sensing system used for test mass in 6 DOFs based on optical lever.The simulation results show that the sensing error in the translational freedom and rotational freedom are about±10^-1010 m and±10^-77 rad,respectly.The sensing resolution on the translational freedom is about 10^-1010 m/Hz ^1/2,rotational freedom is about10^-9 rad/Hz ^1/2.This paper provides a preliminary theoretical basis and guidance for the use of optical levers to achieve displacement measurement of high-precision inertial sensors.