A gravity component-based calibration method for micro-newton thrust stand

Abstract Micro-Newton calibration forces have a wide range of applications, including the determination of key parameters for thrust stands. In previous studies, electrostatic and electromagnetic forces have mainly been used. Although the resolution of these forces is high, ensuring their reliability is difficult. The calibration direction of the device on the balance is inconsistent with the application direction on the thrust stand, which introduces undesired posture errors. The mass of the weights is locally constant and traceable. However, the resolution is low owing to gear friction and machining precision. Therefore, obtaining high-resolution and highly reliable calibration forces remains challenging. In this study, we propose a calibration method based on the gravity component that ensures high reliability by directly using a standard mass and high resolution by moving the ball within the micron range. A theoretical model of gravity component calibration is derived. The effects of errors such as the base tilt and mounting tilt are analyzed. Calibration experiments on an inverted pendulum, hanging pendulum, and horizontal pendulum are conducted, which verify their high linearity, good repeatability, and applicability. The uncertainty of the system is evaluated and the results show that the extended uncertainty is 0.90% at 100 μN. This paper presents a novel method for calibrating micro-Newton thrust stands.