A New Structure of Test Mass for Ground-used Electrostatically Suspended Accelerometer

High-accuracy accelerometer with 1μg precision is in pressing need in sea-air gravimetry and inertial navigation system. Electrostatically suspended accelerometer (ESA) has shown its high resolution when used in low acceleration circumstances. However, when ESA is used on ship or airplane, large noise and drift will be introduced by higher suspension voltage on test mass (TM) which greatly limits the ESA's precision. In this paper, a new TM design with three orthogonal hollow cylinders is proposed. Comparison of mechanical property and preload voltage between this structure and other shapes is conducted in details and the result shows that the new structure has large ratio of surface area to weight and is potentially easy to obtain high producing accuracy. Based on this structure, electrodes for six-freedom degree control is designed and nonlinearity of displacement detection is formulated. By virtue of the low preload voltage and favorable mechanical property, the structure has the potential ability for high-accuracy ESA used on ground.