Study Of Performances Of The High-precision Accelerometer

High precision accelerometer belongs to the category of precise and miniature electromechanical products. The factors influence the performance of accelerometer is coupling which integrates manufacturing, assembly and working conditions. According to the analysis, a constant error of accelerometer can be eliminated by way of compensation, so the stability is an important indicator of the accelerometer, improving the error stability becomes a primary purpose in accelerometer design, process, and debug. The accelerometers are usually hand assembled and their accuracy is strongly depends on the skills and experiences of the workers. High work intensity and man-made mistakes seriously affect product quality. Based on the simulation of the flexure hinged pendulum accelerometer (FHPA), this paper takes disc spring and flex lead which have an impact on the stability of the FHPA as the main study objects, the rigidity characteristic of disc spring and the drift error caused by flex lead are studied in theoretical analysis, experiments and simulations. The optimized disc spring and flex lead are proposed to improve the precision accelerometer.Disc spring is an elastic element in the accelerometer shell depress device, the disc spring deformation will change the preload stress, shell shape and relative position directly, so the stability of disc spring affects the performance of accelerometer. In view of the non-standard disc spring used in accelerometer, the effect of size parameters on zero stiffness characteristic curves are studied with the standard disc spring load-deformation characteristics as the theoretical foundation, the equation of null slope section in stiffness curve is defined to measure the zero stiffness characteristics of disc spring. An experimental device is set up to get disc spring load-deformation characteristics. Disc springs with different heights are studied, negative stiffness characteristics has a tendency of reduction with the decrease of height-thickness ratio. So, suitable ratio is an essential factor for null slope section stiffness of disc spring. Finite element model of depressed device is updated based on experimental results, the effect of height and thickness on null slope stiffness is simulated, and then the optimized parameters of accelerometer are calculated. At last, the optimized non-standard disc spring with null slope stiffness can meet the use of disc spring in working condition.Flex lead is the main reason for the drift error of the FHPA which causes reaction torque as an elastic element in accelerometer. A mathematic modal of flex lead is set up based on handmade coiling styles, FEM analysis is earried out to prove the hypothesis that the reaction torque caused by flex lead is an important source of accelerometer drift error. It is found that coiling style has large influence on drift error by comparing the two hand-made coiling styles. Based on the analysis, several optimized schemes are proposed and proved by the simulation results. It is also found that coiling style has large influence on drift error by comparing the two handmade coiling styles. Several optimized methods are proposed and proved by the simulation results. All these studies provided the theoretical and experimental basis to reduce the drift errors for the FHPA.