微机械陀螺噪声检测及其分析技术研究

发布时间：2018-03-28 04:16

本文选题：球碟转子式陀螺　切入点：噪声分析　出处：《哈尔滨工业大学》2017年硕士论文

【摘要】：陀螺仪作为惯性导航系统的核心部分,它的精度直接影响着导航的准确与安全,近年来已经成为惯性传感器件领域的研究重点。本课题以哈工大MEMS中心自主研发的球碟转子式微陀螺为研究对象,针对该陀螺存在的噪声源进行深入的分析,为进一步提高陀螺精度提供参考。本文首先对整个陀螺系统各部分的工作原理进行了简单的介绍,以此为基础,详细分析了微陀螺机械结构在加工和装配过程中引入的误差对陀螺输出的影响,验证了机械结构误差的存在,并提出抑制该机械噪声的方法;对于检测电路的噪声分析,从噪声源水平和噪声增益两个方面入手,计算检测电路的增益,建立电荷放大器的噪声模型,分析载波信号施加过程中引入的噪声源以及差分支路失配对陀螺输出的影响;对于外界环境存在的电磁干扰,采取相应措施降低其影响。其次,基于交叠Allan方差方法对转子式微陀螺随机误差特性展开了研究。阐述了Allan方差的基本原理和主要随机误差源的统计特征,采用最小二乘拟合方法,对转子式微陀螺中存在的主要噪声源的噪声系数进行表征和辨识,通过各噪声系数的大小反映各噪声源对系统总噪声的贡献,并采用重复迭代法处理拟合结果中存在的负系数项。最后,采用小波阈值去噪法处理转子式微陀螺静态输出数据。经过大量的实验结果对比,最终选择db3作为小波基函数,进行6尺度分解,采用“heursure”阈值准则,软阈值法处理小波系数,通过信号降噪结果前后的对比,可知该降噪方法简单可行,有效地抑制了陀螺仪的随机误差。
[Abstract]:As the core part of inertial navigation system, gyroscope has a direct impact on the accuracy and safety of navigation. In recent years, it has become a research focus in the field of inertial sensor devices. In this paper, the spherical disk rotor micro gyroscope developed independently by MEMS Center of Harbin University of Technology is taken as the research object, and the noise source of the gyroscope is analyzed deeply. In order to further improve the precision of gyroscope, this paper introduces the working principle of all parts of the gyroscope system. The influence of the errors introduced in the machining and assembly of the micro gyro mechanical structure on the gyro output is analyzed in detail, the existence of the mechanical structure error is verified, and the method to suppress the mechanical noise is put forward. Starting from the level of noise source and noise gain, the gain of detection circuit is calculated, the noise model of charge amplifier is established, and the influence of noise source and differential branch mismatch on gyro output is analyzed. For the electromagnetic interference existing in the external environment, corresponding measures should be taken to reduce its impact. Secondly, Based on the overlapping Allan variance method, the random error characteristics of rotor micro gyroscope are studied. The basic principle of Allan variance and the statistical characteristics of main random error sources are described. The least square fitting method is used. The noise coefficients of the main noise sources in the rotor micro gyroscope are characterized and identified. The contribution of each noise source to the total noise of the system is reflected by the magnitude of the noise coefficients. Finally, the wavelet threshold denoising method is used to deal with the static output data of the rotor micro gyroscope. After a large number of experimental results, db3 is chosen as the wavelet basis function. The wavelet coefficients are processed by using "heursure" threshold criterion and soft threshold method. By comparing the results before and after signal denoising, it can be seen that the method is simple and feasible, and can effectively suppress the random error of gyroscope.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN96

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