Research On Key Technologies Of A Tensioned Wire Supporting Accelerometer

In the light inertial navigation system,quartz flexible accelerometer has been dominant for a long time because of its comprehensive advantages in precision and volume.However,quartz flexible accelerometer has encountered the bottleneck of accuracy improvement in recent years,and the error caused by its own measurement principle has become very prominent.Based on the analysis of the problem that restricts the improvement of the accuracy of the quartz flexible accelerometer,this subject proposes an improved method of a feedback drive structure,which using a permanent magnet as a sensitive element,with an external feedback coil as a fixed part and a tensioned wire as a supporting and restraining structure.Besides,this subject analyzed the potential problems of these two new structures.In order to solve these problems,this subject has carried out related research,the main contents are as follows:1)Research on the efficiency improvement of feedback structure.In this subject,the characteristics of the new feedback structure are analyzed,and the existing problems are determined: under the same input of acceleration,compared with the quartz flexible accelerometer,the new feedback structure needs a larger driving force.Usually,the larger driving force often means that it needs a larger current,which will increase the temperature in the system,and then affect the accuracy.In order to solve this problem,this subject mainly starts from the two perspectives of improving the efficiency of electric-force conversion and reducing the demand for driving force of sensitive components.In the feedback coil part,the position with high electric force conversion rate is determined according to the magnitude and direction of magnetic field strength.In the part of sensitive element,the judgment is mainly based on the relationship between the changing driving force demand and the changing feedback electromagnetic force.2)Research on the stiffness design scheme of the tensioned wire structure of the tensioned wire supporting accelerometer.According to the requirements of accelerometer for supporting structure,the wire tensioned structure needs to have high stiffness in the direction of non sensitive axis and low stiffness in the direction of sensitive axis.In this subject,the stiffness models of different wire tensioned structures in the direction of non sensitive axis are studied,and the related factors affecting the stiffness of wire structures are analyzed and determined.In the direction of the nonsensitive axis,the length,cross-sectional area and elastic modulus of the tensioned wire are the main factors affecting the stiffness.In the direction of the sensitive axis,the pretension and length of the tensioned wire are the main factors affecting the stiffness.Finally,the new structure is simulated by related software,and the correctness of the theoretical analysis is verified.In addition,a principle verification platform is built to test the function and performance of the tensioned wire supporting accelerometer,which proves the correctness and feasibility of the principle.The test prototype of the tensioned wire supporting accelerometer shows good performance of 5.34μg in 0g output stability within an hour,and shows great potential in accuracy.