Magnetically-levitated thrust stand for evaluating 6-component thrust vector of 1-N class onboard propulsion devices

This paper describes a magnetically-levitating thrust stand for the measurement of the six-component thrust vector of onboard propulsion devices. Conventionally, the thrusts of such devices that yield small thrust-to-weight ratios have been measured using pendulums, which can reduce the influence of gravitational force on the thrust measurement. The conventional thrust stand successfully measures the thrust with enhanced accuracy; however, the thrust vector is difficult to evaluate as the thrust vector measurement requires a higher degree of freedom for the pendulum. Hence, the authors propose the use of magnetic levitation of the thruster using voice coil motors, which have the appropriate characteristics for small thrust evaluation: linearity and responsiveness. A 1-N class prototype was designed to show that the six-component thrust vector can be measured using the magnetically-levitating thrust stand. The prototype evaluated 0.5-N class six-component thrusts, whereas the conventional pendulum-type thrust stands were unable to determine the thrust vectors. Moreover, the calibration shows that the thrust stand accurately evaluated the reference thrust vector with a coefficient of determination higher than 0.988.