A Piezoelectric Balance System With Mass Automatic Recognition Ability Based on Resonant Frequency Shift

Mass measurement in the microgravity environment is a crucial technology promoting space science experiments. Here, a piezoelectric balance (PEBL) based on resonant frequency shift is proposed to achieve mass measurement for microgravity environment. The structural and electrical designs of the PEBL are elaborated, and the theoretical modeling is accomplished to carry out parameter analysis. The finite-element method (FEM) simulation is used to analyze the vibration modes and verify the relationship between the resonant frequency shift and the measured mass, in which the working mode of the PEBL is determined; the impact resistance of the PEBL is analyzed, which shows that it can resist acceleration overload of larger than 50 times the gravity acceleration. A prototype is developed and its vibration characteristics and impedance characteristics are tested experimentally. The experiments successfully verify the effectiveness of theoretical analysis. Furthermore, an automatic mass recognition system is developed to achieve fast detection of the resonant frequency and the measured mass. The developed PEBL system achieves measurement range of 283.36 g with measurement uncertainty of about 1.22% (3.47 g). It is a suitable candidate for mass measurement in microgravity environment with merits of independence on the acceleration field, low power consumption, structure miniaturization, and configuration simplification.