| The measurement of impulse or thrust is necessary to develop and evaluate a spacecraft propulsion device.In this paper,based on the realistic demand of micro-impulse measurement of low-impulse-mass-ratio pulsed thruster,several research,including the measurement of response characteristics of large mass body under small transient impulse,design of thrust stand,impulse calibration method,design and test of the experiment system,are carried out.According to the characteristics of low-impulse-mass-rate pulsed thruster with large mass as well as low impulse,a micro-impulse measurement scheme based on critical-stress thrust stand is chosen.By adopting the combination of theoretical modeling and numerical simulation,the response characteristics of the thrust stand to the impulse are analyzed.Additionally,the overall structure of the thrust stand is designed.And the designing process of important components of the thrust stand,including the structure of the supporting metal sheet,angle measurement,leveling and locking devices and other components,are analyzed.Moreover,thrusters weighing between 80 to 200 kg can be effectively measured based on the structure scale of the thrust stand.The experimental thrust stand for micro-impulse measurement are manufactured.The calibration experiments were carried out by using the pendulum method.By analyzing the experimental data,the calibration coefficient k is calculated as 2.40Ns/mm.And the calibration results show that the critical stress platform can effectively measure the low impulse from 10 to 100 mNs.And the error is less than 8%.In order to guarantee the reliability of the experimental test,the operation procedure of the ground experiment of pulsed thrusters were put forward.The main aspects where the experimental results would be affected in the measuring process,including the ground noise of environment vibration,mechanical processing and assembly of various components and the thermal effects of supporting metal sheets,are analyzed. |
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