The Design And Analyse On Two Axes Flexure Hinges Gradiometer Based On The Principle Of Torsion Measurement

The gravitational field can be described by the gravity potential, the gravity acceleration vector, and the gravity gradient. The gravity gradient is the second derivative of the gravity potential, so it can tell us more details of the gravitational field comparing with the gravimetric measurement. The measurement of the gravity gradient has many advantages. It not only is very sensitive to the disturbance of the density of the Earth, which can reflect the slim change of the geological structure, but also can be separated from the inertial acceleration. The gravity gradiometer behaves important application in the fields of the Earth science, such as inertial navigation, geophysics, earthquake, geology science, Earth's resource survey and so on.In general speaking, gravity gradient measurements are divided into two models, one is differential acceleration measurement, and another is torque measurement model. To satisfy the needs of the geological exploration, a two-dimension flexure hinges gravity gradiometer is designed with 1E measurement precision in this paper. The design of the flexure hinges gradiometer, the capacitance detection and their coupling effect, and the error analysis are studied. My main works in this thesis are listed as follows:(1) Based on the E?tv?s torsion balance, a two-dimension flexure hinges gravity gradiometer combined with a high sensitivity capacitive transducer is designed, and its according parameters are analyzed.(2) The measuring principle of the two-dimension capacitance transducer and the influence of the coupling effect upon the capacitance output are discussed.(3) The limits of the thermal noises of the whole system and the uncertainty of the swinging table on the gravity gradient measurement are discussed in detail.