Research on Electrostatic Suspension Two-dimension Tiltmeter

Friday, 19 December 2014
Shuchao Wu1, YanZheng Bai1, Shaobo Qu1 and Zebing Zhou2, (1)Huazhong University of Science and Technology, Wuhan, China, (2)Institute of Geophysics, HUST, Wuhan, China
It is quite important to measure the ground tilt for geophysics research and great civil engineering projects. In application, the drift of the instrument should be carefully considered, and the ground tilt which is measured by a low drift tiltmeter will be more valuable for the earthquake prediction research and the high building safety evaluation. The electrostatic suspension two-dimension tiltmeter is a new style tiltmeter. The key part of this tiltmeter is a sandwich type sensor-head which is composed of a proof mass and six pairs of capacitor electrode plates. By six-degree-of-freedom control, the proof mass will be maintained motionless in the middle of electrode plates by the electrostatic force. In the vertical direction, a high control voltage is required to perform the electrostatic suspension of the mass under gravity condition. While in the horizontal direction, the control voltage can be relatively low because the electrostatic force is just used to balance the component of gravity in such direction, which is caused by the tilt of the instrument base. By measuring the control voltage of the two horizontal directions, the ground tilt in these two directions can be obtained. Comparing with the traditional pendulous tiltmeters, the mechanical drift, which is the main shortcoming of the traditional pendulous tiltmeters, can be overcome in this new tiltmeter, because the proof mass will be suspended by the electrostatic force, there will be no mechanical linkage between the proof mass and the frame. Because of the advantage of low drift, it is quite suitable to use this new tiltmeter for earthquake prediction research and high building safety evaluation.