Research On Thrust Measurement Technology Of Millinium Ion Thruster

With the development of space technology,modern space missions require more and more accurate flight trajectory of the aircraft,so it is bound to require the thruster to produce a stable millinium level or even micro nium level thrust.At present,there are many kinds of thrusters to meet the flight mission of the aircraft,including solid micro thruster,liquid micro thruster and gas micro thruster.As the performance test device of thruster,the micro thrust measurement technology of thruster has a high guiding significance for the research and development of thruster.Based on the performance of a certain type of LIPS developed by the Lanzhou Institute of Space Physics,this paper has developed a millinew-level thrust measurement device,which mainly includes a balance weak force compensation device,a trapezoidal torsion pendulum test stand,a damper,etc.,to complete the balance weak force compensation The calibration experiment of the device and the thrust measurement experiment of the thruster.The developed balance weak force compensation device uses the magnetic effect produced by two energized coils and the interaction force of the magnetic core.Based on theoretical analysis and Comsol simulation,the feasibility of the scheme is determined,and the balance weak force compensation device is designed.Through experiments,the function relationship between the current and the force on the magnetic core is calibrated F=0.3372X+0.0794,the input current ranges from 0.02 m A-150 m A,the weak force generated is 0.0852 m N-50.6594 m N,and the relative error is 0.15%.A new type of trapezoidal torsion pendulum structure is designed.Through theoretical analysis and experiment,the device has the characteristics of simple installation,quick debugging and adjustable sensitivity.The structure,the weak force compensation device and the micro thrust control device form a closed-loop test system.The PSD sensor transmits the angular displacement change of the suspension arm to the micro thrust measurement control device,and the micro thrust measurement control device transmits the signal to the balance weak force compensation device,so as to control the swing of the suspension arm.The thrust measurement of a certain type of thruster of the LIPS series has been completed.The measurement result is: when the thruster is in working state 1,the average thrust F＿measure = 5.8103 m N,and the relative error is 0.13%;when the propeller is in working state 2,F＿Measure=10.5526 m N,the relative error is 0.067%;when the propeller is in working state three,the average thrust F＿measure=15.9011 m N,the relative error is0.049%;when the propeller is in working state four,the average thrust F＿measure=20.1002 m N.The relative error is 0.031%.Finally,the influence of the relative position of the two coils and the magnetic core on the calibration coefficient is simulated,the factors that may affect the experimental results are analyzed,and the corresponding solutions are proposed.