Research About Test Methods Of The Electrostatic Feedback Tiltmeter

The measurement of earth tilt is an important way of studying earth crust deformation and its earth tide,which means much to the research of Geodynamics and the observation of earthquake prognostic.The electrostatic feedback tiltmeter is a novel digital earth crust deformation observing instrument.By applying the structure of a single-line hanging pendulum,the technology of electrostatic accelerometer and the feedback electrostatic technology,the electrostatic feedback tiltmeter can measure ground tilt and ground rotating at the same time,has a wider dynamic range,a better linearity and a wider observation frequency band.This article introduces the measurement mechanism of the electrostatic feedback tiltmeter,the theory of observation accuracy assessment,the test methods of the technical specifications and the theoretical calculation of measurement error of the instrument.The main research contents are as follows:(1)By using mechanical vibration theory,the article deduces the dynamic equation of the mechanical part and the working mechanism of the sensor.The measurement mechanism of the electrostatic feedback tiltmeter is described in detail.(2)The test of instrument technical specifications is important during the development and the test of the electrostatic feedback tiltmeter.The source of uncertainty of measurement,the difference between error and uncertainty of measurement and the methods of evaluation of uncertainty of measurement are introduced.The testing result of instrument technical specifications is evaluated by the theory of uncertainty of measurement.(3)Span,Resolution,Linearity and maximum permissible errors are key technical specifications of the electrostatic feedback tiltmeter.Their accuracies have huge influences on the results of observations.Based on the earthquake observation technical standards and the principle of this new tiltmeter,this article researches the methods to test the technical specifications of tilting and rotating.(4)The pendulum of the electrostatic feedback tiltmeter is hanged by a single metal string,which enables the free movement in the direction of sensitive axis.This article analyses the influence of quadrature coupling and calculated the influence theoretically.Moreover,other environment influences,such as temperature and magnetic field,is analysed as well.Their test method is also designed in this article.