Pulsed μNewton thrust measurement with torsional thrust stand

Abstract

Microspacecraft plays an important role in space missions recently. And micro thrusters are the essential components for the microspacecraft to stabilization, pointing and position keeping. The technology of micro thrust measurement can evaluate the performance of micro thrusters. This paper designed a thrust stand based on the torsional beam for measuring the average thrust of pulsed micro thrusters. When pulsed thrust (the frequency of the pulsed thrust must be much larger than the natural frequency of the stand) is applied to the beam, the beam responses in horizontal plane by rotating about its axis. And the average thrust of the pulsed thrust is linear with the steady-state deflection angle of the beam. The static calibrations were performed based on the assembly of the multiturn coil and the permanent magnet. And the calibration results demonstrate good repeatability and good linearity. The thrust stand can theoretically measure the thrust up to 609.6 μN with a resolution of 24.4 nN. The assembly of the multiturn coil and the permanent magnet was also used as an exciter to further research the performance of the thrust stand. Three sets of force pulses with the same magnitude, the same pulse width and the different repetitive frequency were measured. The results demonstrate good measuring repeatability and the relative error is about 7.04%, 1.78% and 5.08% respectively.