硅微谐振加速度计的温度特性

硅微谐振加速度计以其小体积、低成本和高精度的频率信号输出,成为硅微惯性传感器研制的热点之一.温度特性是影响硅微谐振加速度计精度水平的重要因素.在分析硅微谐振加速度计工作机理的基础上,从结构设计方法、工艺流程加工和闭环控制回路方面分析了温度对零位和标度因数的影响因素,同时给出了相应解决措施.研制的硅微谐振加速度计基频约为17 kHz,标度因数约220 Hz/g,在-40~+70℃范围内,谐振频率的温度系数为-71.5×10-6/℃,标度因数的温度系数为-610×10-6/℃,样机在常温下谐振频率的相对稳定性为0.313×10-6,1.5 h 零偏稳定性达到42.5μg.     

硅微谐振加速度计的模态分析与实验

针对硅微谐振加速度计在进行结构设计时,如何根据模态特性选取工作模态这一问题,比较分析了加速度计工作在两种不同振动模态下的性能参数。首先采用刚度法分析了谐振器的振动特性,得出能够反映谐振器振动状态的两种模态即同相振动模态和反相振动模态,结合理论推导和仿真结果得出两种振动模态下谐振频率差值与标度因数差值呈线性关系;其次通过分析两种振动模态下的能量分布情况,得出两种振动模态下谐振器的品质因数与振梁振动幅值之间的关系,同相模态振动一个周期所消耗能量约为反相模态所消耗能量的2倍;最后通过评估硅微谐振加速度计的噪声,阐明了两种振动模态下部分噪声分量不同的原因并进行了实验验证。实验结果表明,在相同驱动电压下,同相模态相比反相模态总体噪声增大25.7%。该研究为设计硅微谐振式加速度计时,确定谐振器的振动模态及驱动方案提供了参考依据。     

硅微谐振式加速度计结构设计与仿真

硅微谐振式加速度计以易于检测的准数字信号作为输出,是微传感器的一个研究热点.提出一种基于一级微杠杆放大机构和DETF谐振器的硅微谐振式加速度计的结构设计,在分析工作机理以及误差来源的基础上阐述硅微谐振式加速度计的设计要点;结合现有加工工艺水平完成整体结构设计;运用MATLAB分析结构参数对性能的影响并对参数进行优化设计;运用ANSYS对加速度计整体结构进行仿真验证.所设计加速度计的谐振频率约29 kHz,标度因数为95 Hz/g,量程为±50g,其差分输出频率的线性度为0.099%.经研究表明,在加速度计的结构设计中,量程范围要与谐振嚣原理性误差协调考虑;谐振器振幅不宜过大;在现有加工工艺条件下,谐振器振梁的宽度产生的加工误差最大,对谐振器的性能影响最大.     

硅微机械谐振式陀螺仪

介绍了硅微机械谐振式陀螺仪的工作原理，给出了硅微机械谐振式陀螺仪的动力学方程详尽推导。针对此方程进行仿真研究，对结构设计参数进行了估计。研究表明，硅微机械谐振式陀螺仪是一种很有发展前途的新型陀螺仪。     

一种双质量硅微陀螺仪

双质量块结构形式的硅微陀螺仪能够有效消除轴向加速度等共模干扰的影响。利用结构解耦方法设计了一种新型的双质量双线振动式硅微机械陀螺仪。依据双质量硅微陀螺的结构和工作原理,通过简化的动力学方程,对该陀螺的驱动和检测模态进行了理论分析,并利用Ansys有限元软件对陀螺的驱动和检测模态进行了数值仿真。仿真结果表明,该陀螺结构设计能够实现驱动和检测模态的完全解耦,从而验证了设计思想的正确性。通过仿真,得到了驱动和检测模态的仿真频率值。在对微陀螺加工所采用的加工工艺进行简单介绍后,对加工出的硅微机械陀螺仪样品的模态频率值进行了电路测试。由于加工误差的存在,实验得到的驱动和检测频率值与仿真设计值存在1.6%的误差。最后在转台上对样品的标度因数进行了测定,得到了该双质量硅微陀螺仪的标度因数为2.518mV/((°)?s-1)。     

振动轮式硅微陀螺仪检测轴的闭环特性

研究了振动轮式硅微陀螺仪敏感结构的谐振特性,重点进行了检测轴的闭环控制系统分析和测试。通过对不同气压条件下检测轴谐振特性的研究及驱动轴和检测轴谐振频率匹配的试验,分析了静电力反馈控制系统中的变刚度问题,进行了硅微陀螺仪检测轴的闭环控制系统设计,给出了检测轴闭环控制系统的原理框图和传递函数,同时分析了闭环条件下驱动轴回路和检测轴回路各部分的相位关系以及正交分量的消除方法。试验结果表明闲环控制提高了硅微陀螺仪的精度指标。     

高精度硅微谐振加速度计工程化设计与实现

硅微谐振加速度计因具有小体积优势和高精度潜力,成为硅微惯性传感器研制的热点之一。工程化设计是硅微谐振加速度计从原理样机向成熟产品转化过程中的关键步骤之一。在分析硅微谐振加速度计工作机理的基础上,从工程实用化设计角度出发,提出了一种高精度硅微谐振加速度计工程化设计方法。分别从系统设计、结构设计、控制电路设计和测试与补偿技术等方面进行了分析和对比,讨论了误差来源与改进方法。测试表明,设计的高精度硅微谐振加速度计质量块基频大于3 k Hz,谐振音叉中心频率约18 k Hz,标度因数大于100 Hz/g,量程±40 g,死区小于0.67 mg,带宽大于200 Hz,振动整流误差0.344 mg,零位一次通电稳定性优于50μg,测试结果基本满足工程化应用指标。     

提高旋转载体驱动微机械陀螺标度因数稳定性的算法

旋转载体驱动微机械陀螺是一种新型的振动式MEMS陀螺,它没有微机械陀螺通常所具有的驱动结构,而只有检测模态。它安装于旋转载体上,巧妙地利用了载体的自旋作为驱动,从而使得敏感质量获得角动量。当载体发生横向转动时,敏感质量将受到科里奥利力的作用。在进动力矩、弹性力矩和阻尼力矩的共同作用下,敏感质量将产生周期性振动。振动频率对应于载体自旋频率,振动幅度与载体输入角速度大小成比例。由此工作机理,得出了敏感元件的动力学方程,并基于动力学方程建立了陀螺标度因数的误差模型。接着,根据误差模型,对标度因数的稳定性进行了分析和实际测试。分析和实验数据说明,载体自旋频率的变化是造成标度因数不稳定的主要原因。为了保证陀螺测量精度,提出了一种抑制载体自旋频率变化对标度因数影响的补偿算法,提高标度因数稳定性。最后,针对该算法的有效性,进行了实验验证。实验结果表明,此种方法能有效地提高标度因数的稳定性,标度因数相对于自旋频率变化的影响因子由补偿前的1.31 m V/(°/s)/Hz下降至7.14×10-3 m V/(°/s)/Hz。     

基于电压约束的微机械谐振器幅-频耦合抑制方法

针对微机械谐振器中存在的幅度-频率耦合带来振动稳定性变差的问题，提出了一种闭环自激控制的直流参考电压约束方法来抑制谐振器振幅。首先，从理论上分析了决定谐振器临界振幅的因素，利用计算机视觉辅助测量方法和高频方波调制方法获得相关尺寸参数及品质因数计算得到微机械谐振器的临界振幅。然后，提出频谱边带比的振动幅度测试方法实现封装后的振动幅度测试。最后，构建了自激振荡闭环测控电路分析模型，根据临界振幅计算得相应的临界直流参考电压为0.866V。恒温实验测试表明：直流参考电压为0.4 V（小于临界参考电压）时，谐振器能够稳定地保持恒定幅度振动；直流参考电压为1.0 V（大于临界参考电压）时，谐振器振动幅度不恒定，谐振器稳定性变差，所提方法通过确定临界参考电压值，并将直流参考电压约束在临界参考电压以内能有效抑制幅度-频率的耦合。     

硅微谐振加速度计交流检测信号解耦技术

硅微谐振加速度计以高精度的频率信号输出及潜在的敏感结构与处理电路实现一次集成的优势,成为硅微传感器研制的热点之一。针对交流检测信号耦合效应对硅微谐振加速度计性能的重要影响,在分析硅微谐振加速度计工作机理的基础上,从结构和电路两方面研究了交流检测信号耦合效应的来源,分析了耦合效应对检测电路和闭环控制精度的影响。采用双质量块结构方案和电路优化设计所研制的硅微谐振加速度计,基频为15 kHz,标度因数为36 Hz/g,量程为±30 g。试验证明耦合效应对仪表性能的影响降低到0.3 mg以内。     

Dynamic analysis of a dielectric elastomer-based microbeam resonator with large vibration amplitude

A non-linear vibration equation with the consideration of large amplitude, gas damping and excitation is developed to investigate the dynamic performance of a dielectric elastomer (DE)-based microbeam resonator. Approximate analytical solution for the vibration equation is obtained by applying parameterized perturbation method (PPM) and introducing a detuning variable. The analysis exhibits that active tuning of the resonant frequency of the resonator can be achieved through changing an applied electrical voltage. It is observed that increasing amplitude will increase the natural frequency while it will decrease the quality factor of the resonator. In addition, it is found that the initial pre-stretching stress and the ambient pressure can significantly alter the resonant frequency of the resonator. The analysis is envisaged to provide qualitative predictions and guidelines for design and application of DE-based micro resonators with large vibration amplitude.     

Control of nonlinear vibrations of vibrating ring microgyroscope

The influence of the basement rotation on the variations in the spectrum of vibration frequencies of thin elastic shells and rings was known already at the end of the 19th century [1]. The physical phenomenon of inertness of elastic waves occurring free vibrations of an axisymmetric body, first explained in [2], were practically used in developing new types of gyros [2–6]. The foundations of the theory of wave gyros were laid in [2, 4], and the errors of such gyroscopes for various shapes of the vibrating resonator were studied in [2, 4, 7, 8]. It was shown that the error of the resonator manufacturing (the variable density, thickness, anisotropy of the material elastic properties, etc.) [2, 8] and the geometric nonlinearity of the resonator flexural vibrations studied in [2, 7] lead to splitting of the natural frequency of flexural vibrations [2], which is reflected in the wave picture of the resonator vibrations and characterizes the gyroscope precision.In the present paper, we study the errors of the vibrating microgyroscope which arise because of nonlinear elastic properties of the ring resonator material. We construct a control of the potential on the electrodes which allows one to maintain the prescribed amplitude of the normal resonator deflection and compensate for the gyroscope errors arising because of the nonlinear elastic properties of the material.     

A micromechanical mass sensing method based on amplitude tracking within an ultra-wide broadband resonance

We propose a mass sensing scheme in which amplitude shifts within a nonlinear ultra-wide broadband resonance serve as indicators for mass detection. To achieve the broad resonance bandwidth, we considered a nonlinear design of the resonator comprised of a doubly clamped beam with a concentrated mass at its center. A reduced-order model of the beam system was constructed in the form of a discrete spring-mass system that contains cubic stiffness due to axial stretching of the beam in addition to linear stiffness (Duffing equation). The cubic nonlinearity has a stiffening effect on the frequency response causing nonlinear bending of the frequency response toward higher frequencies. Interestingly, we found that the presence of the concentrated mass broadens the resonant bandwidth significantly, allowing for an ultra-wide operational range of frequencies and response amplitudes in the proposed mass sensing scheme. A secondary effect of the cubic nonlinearity is strong amplification of the third harmonic in the beam’s response. We computationally study the sensitivity of the first and third harmonic amplitudes to mass addition and find that both metrics are more sensitive than the linearized natural frequency and that in particular, the third harmonic amplitude is most sensitive. This type of open-loop mass sensing avoids complex feedback control and time-consuming frequency sweeping. Moreover, the mass resolution is within a functional range, and the design parameters of the resonator are reasonable from a manufacturing perspective.     

硅微型两自由度振动轮式陀螺仪的研究

本文详细介绍了一种利用微电子加工工艺制作的硅微型两自由度振动轮式陀螺仪的新结构 ,分析了该种陀螺仪的工作原理 ,推导了陀螺仪动力学方程 ,并讨论了梳状谐振器的工作机理和陀螺仪模拟力反馈的闭环控制方案 ;目前已制作完成了该型陀螺仪的原理样机     

宽带光源光谱不对称性对光纤陀螺性能的影响

光谱不对称性是宽带光源的非理想特性之一,这种特性对标度因数的影响在中高精度光纤陀螺中会逐渐显现出来。为了分析光谱不对称性及其对光纤陀螺的影响,结合光纤陀螺所用宽带光源的典型光谱参数,对宽带光源的光谱不对称性进行了理论计算,分析了传统量化光谱不对称性方法存在的问题和局限性,并在此基础上提出了一种更加准确合理的光谱不对称性的量化指标。研究表明,光谱不对称性会产生相对相位误差,并在调制通道中产生视在增益误差,导致陀螺第二反馈回路"错误"调整调制通道的增益,引起光纤陀螺标度因数的非线性误差。对于类矩形光谱当不对称度小于10~(-2)时,视在增益误差引起的标度因数非线性误差会达到25′10~(-6)。因此在进行光源设计时需要将光谱不对称性作为一个定量考虑的指标。     

挠性捷联惯性导航系统误差补偿技术

为了补偿载体角运动和振动引起的捷联惯性导航系统导航误差,通过分析载体角运动引起的圆锥误差,挠性陀螺刻度因数非线性、姿态角速率引起的加表零位变化等因素对导航结果的影响,采用三子样算法和非线性补偿技术,对上述误差进行了补偿。摇摆试验和跑车试验证明,通过上述补偿后,姿态精度、水平定位精度、垂直定位精度有明显的提高。     

Linear,nonlinear dynamics,and sensitivity analysis of a vibratory ring gyroscope

The linear and nonlinear dynamic responses of a vibratory ring gyroscope are investigated in this study focusing on the response mechanism of such a vibratory gyroscope. It is found that the nonlinear equations governing the drive and sense directions are coupled through both inertial linear and geometric nonlinear terms. Nonlinear responses are studied based on the full coupled nonlinear dynamic equations. The varying amplitude on the sense direction is analyzed for different input angular rates. The effect of nonlinearity on the ring gyroscope system is performed by comparing the results of nonlinear responses to those of linear responses. The contributions of some parameters to the amplitude responses and gyroscope sensitivity are analyzed, the conclusions of which provide guidelines to improve the sensitivity of the vibratory ring gyroscopes.