Research on Ground Vibration and Isolation Methods in Dynamic Micro-thrust Measurement

In the field of dynamic microthrust measurement, ground vibration noise poses a particularly complex and formidable challenge, significantly disrupting measurement accuracy, especially in dynamic scenarios. This paper proposes a negative stiffness isolation method based on a compliant parallel mechanism, aiming to mitigate torsional vibration noise caused by ground lateral or angular vibrations. This approach enhances the dynamic resolution of thrust measurement to 0.1 μN. The transfer matrix method is employed to systematically analyze the dynamic behavior of a multi-stage vibration isolation system, establishing the input-output force and displacement relationships across isolation stages for a quantitative evaluation of vibration transmission characteristics. Additionally, the paper addresses low-frequency compensation, where gravity and other factors can affect the system’s steady-state performance. Differential measurement using symmetrically placed torsion pendulums is introduced to reduce the impact of low-frequency drift on system performance. Through in-depth theoretical modeling and extensive simulation experiments, the dynamic characteristics of the system, multi-stage vibration isolation strategies, and the vibration isolation effects under various working conditions are comprehensively explored. This validates the effectiveness of the proposed integrated approach in isolating high-frequency dynamic responses and achieving precise vibration isolation across the frequency range from 0.01 Hz to 10 Hz.