Design And Research Of The Micro-thrust Measurement Experiment Device

Since Coulomb and Cavendish firstly applied the torsion pendulum to precisely measure the electromagnetic force and gravitation attraction, the torsion pendulum as a main precision measurement tool is widely used in many research areas such as precision measurements and material characteristics. At present, the precision torsion pendulum is internationally recognized one of the most sophisticated instrumentation of the micro-force or torque detection on the ground.This paper, to the micro-thrust measurement of the space propulsion device as the research object, uses the design scheme of the torsion pendulum hanging propulsion device measuring micro-thrust, builds the micro-thrust measurement experimental platform, preliminary designed a full of the torsion pendulum measuring micro-thrust system, including torsion wire fixture, torsion pendulum insulated connection appliance, circuit design of the propulsion device, tungsten wire annealing treatment device, light lever principle reference system, and plane-parallel capacitor applied micro-thrust device, etc. In the principle experiment for a laboratory condition, we accurately calibrate the tungsten torsion elastic coefficient, in addition, to the torsion pendulum vibration modeling, calculate the measurement calibration frequency, obtains the relative error of measurement value and theoretical calculation value for 0.11%, and proves that the measurement calibration of the tungsten torsion elastic coefficient is peculiarly accurate. Meanwhile, in the principle experiment for a laboratory condition, the micro-thrust measurement experiment device measures the plane-parallel capacitor generating the micro-thrust range for 54-323μN, measurement precision attains 2μN. And then, to the torsion pendulum dynamic modeling, dynamically calculates and analysis the torsion pendulum micro-thrust measurement experiment results, obtains the average relative error in the torsion pendulum measurement micro-thrust experiment for 0.027%.Experiments found that the noise, air flow and ground vibration interference limits the minimum measurement force of torsion pendulum. In order to improve the limit of the torsion pendulum measurement force, we design the eddy depletion magnetic damping system to reduce the noise and air flow interference on the influence of the torsion pendulum. At present, we have completed theoretical calculation of magnetic damping system, laid the foundation for the next stage experiment.