基于MEMS加速度计与磁力计的位移计设计

基坑水平位移监测是基坑安全的重要检测项目之一。针对现有的阵列式位移计在基坑水平位移监测中容易产生扭转误差的问题,设计了一种基于MEMS加速度计与磁力计的位移计,能够同时满足基坑水平位移与沉降位移监测的需求。介绍了位移计自动化实时监测系统组成。对位移计的结构以及监测节的硬件电路进行了设计,并制作完成了位移计样机。阐述了位移计通过对加速度计与磁力计的数据进行融合,计算位移坐标的测量原理和扭转误差校正的方法。最后通过模拟监测节间发生扭转时位移计水平位移监测的实验,以及位移计沉降位移监测试验。实验结果表明,该位移计能够精确测量水平与沉降位移,并能够有效校正位移计竖直安装时监测节扭转带来的扭转误差。

MEMS加速度计全温性能优化方法

针对微机电系统(MEMS)加速度计全温性能低的问题,提出锚区应力对消方法、低应力粘接工艺和温度补偿方法。首先,通过调整两个键合的锚区面积大小实现锚区应力对消,使得加速度计的温度性能得到改善;然后,建立加速度计堆叠封装模型并对专用集成电路(ASIC)粘接参数、加速度计敏感结构点胶方式与点胶参数进行仿真分析,从而确定了加速度计的低应力粘接形式和粘接工艺;最后,对加速度计零偏和标度因数设计了三阶温度补偿方法并进行了实验测试。实验结果表明,加速度计全温零偏稳定性达到47.3μg(1σ)、全温标度因数稳定性达到43.6 ppm(1σ),提高了加速度计的全温性能。

Suitable triggering algorithms for detecting strong ground motions using MEMS accelerometers

With the recent development of digital Micro Electro Mechanical System （MEMS） sensors, the cost of monitoring and detecting seismic events in real time can be greatly reduced. Ability of MEMS accelerograph to record a seismic event depends upon the efficiency of triggering algorithm, apart from the sensor＇s sensitivity. There are several classic triggering algorithms developed to detect seismic events, ranging from basic amplitude threshold to more sophisticated pattern recognition. Algorithms based on STA/LTA are reported to be computationally efficient for real time monitoring. In this paper, we analyzed several STA/LTA algorithms to check their efficiency and suitability using data obtained from the Quake Catcher Network （network of MEMS accelerometer stations）. We found that most of the STA/LTA algorithms are suitable for use with MEMS accelerometer data to accurately detect seismic events. However, the efficiency of any particular algorithm is found to be dependent on the parameter set used （i.e., window width of STA, LTA and threshold level）.

Summary of Research Status and Application of MEMS Accelerometers

The rapid development of MEMS technology has made MEMS accelerometers mature and the application range has been expanded. Many kinds of MEMS accelerometers are researched. According to the working principle of MEMS accelerometer, it can be divided into: piezoresistive, piezoelectric, capacitive, tunnel, resonant, electromagnetic, thermocouple, optical, inductive, etc. Due to its outstanding features in terms of size, quality, power consumption and reliability, MEMS sensors are used in military applications and where high environmental resistance is required. MEMS accelerometers are developing rapidly and have good application prospects. In order to make MEMS accelerometers more widely understood, the advantages of MEMS accelerometers are expounded. The research status of MEMS accelerometers is introduced, and MEMS are analyzed. The application of accelerometers in real-world environments, and the development trend of MEMS accelerometers in the future. More scholars will invest in MEMS accelerometer research, pursuing high performance, low power consumption, high precision, multi-function, and interaction. Strong MEMS accelerometers will be ubiquitous in the future.

Lumped parameter analytic modeling and behavioral simulation of a 3-DOF MEMS gyro-accelerometer

A new analytical model of a 3-degree-of-freedom （3-DOF） gyro-accelerometer system consisting of a 1-DOF drive and 2-DOF sense modes is presented. The model constructs lumped differential equations associated with each DOFof the system by vector analysis. The coupled differential equations thus established are solved analytically for their responses in both the time and frequency domains. Considering these frequency response equations, novel device design concepts are derived by forcing the sense phase to zero, which leads to a certain relationship between the structural frequencies, thereby causing minimization of the damping effect on the performance of the system. Furthermore, the feasibility of the present gyro-accelerometer structure is studied using a unique discriminatory scheme for the detection of both gyro action and linear acceleration at their events. This scheme combines the formulated settled transient solution of the gyro-accelerometer with the processes of synchronous demodulation and filtration, which leads to the in-phase and quadrature components of the system＇s output signal. These two components can be utilized in the detection of angular motion and linear acceleration. The obtained analytical results are validated by simulation in a MATLAB/Simulink environment, and it is found that the results are in excellent agreement with each other.

A Survey of Error Analysis and Calibration Methods for MEMS Triaxial Accelerometers

MEMS accelerometers are widely used in various fields due to their small size and low cost,and have good application prospects.However,the low accuracy limits its range of applications.To ensure data accuracy and safety we need to calibrate MEMS accelerometers.Many authors have improved accelerometer accuracy by calculating calibration parameters,and a large number of published calibration methods have been confusing.In this context,this paper introduces these techniques and methods,analyzes and summarizes the main error models and calibration procedures,and provides useful suggestions.Finally,the content of the accelerometer calibration method needs to be overcome.

基于IAO的随钻MEMS加速度计误差参数识别方法

针对随钻测量中MEMS加速度计器件误差变化难以精确识别的问题,提出一种基于改进天鹰算法(IAO)的随钻MEMS加速度计误差参数识别方法。首先根据MEMS加速度计输出模型变换得到非线性误差函数,采用天鹰算法(AO)求解到非线性误差函数的最优值。在AO算法基础上,利用误差参数平均值和迭代次数改善AO算法开采参数的全局搜索能力,基于误差参数最优值和平均值构造径向因子提高AO算法误差参数识别精度。然后采用IAO算法极限逼近非线性误差函数的参数最优值,并通过采样点插值误差数据库完成误差参数校准。最后将IAO算法应用于识别加速度计误差参数,结果表明:IAO算法识别精度比PSO算法、SSA算法和AO算法提高了1~2个数量级,补偿后的加速度计输出误差明显减小。

Comprehensive Warpage Analysis of Stacked Die MEMS Package in Accelerometer Application

Packaging of MEMS ( micro-electro-mechanical system ) devices poses more challenges than conventional IC packaging, since the performance of the MEMS devices is highly dependent on packaging processes. A Land Grid Array ( LGA ) package is introduced for MEMS technology based linear multi-axis accelerometers. Finite element modeling is conducted to simulate the warpage behavior of the LGA packages. A method to correlate the package warpage to matrix block warpage has been developed. Warpage for both package and sensor substrate are obtained. Warpage predicted by simulation correlates very well with experimental measurements. Based on this validated method, detailed design analysis with different package geometrical variations are carried out to optimize the package design. With the optimized package structure, the packaging effect on accelerometer signal performance is well controlled.

基于RBF的MEMS加速度计温控系统设计

针对微机电系统(MEMS)加速度计受到温度变化影响较大、产生不同程度的漂移和测量误差,难以满足工业机器人领域高精度导航的问题,提出一种提高MEMS精度的温度补偿方法。利用热电制冷器设计适用于嵌入式的温度控制系统,使MEMS传感器的工作温度相对稳定。利用MPU6050的MEMS加速度计,设计一种基于STM32主控的嵌入式温度控制系统,并通过上位机采集数据,对比分析改进径向基函数(RBF)、RBF和常规PID等算法的温控效果。结果表明:在当前的PID控制参数的条件下,改进的RBF整定效果相对于RBF-PID和经典PID,在超调量、稳态误差、调节时间等指标上,表现出更优的系统响应和控制精度,超调量降低41.3%,调整时间减低52.3%,系统对温度的控制精度约为0.04℃。

一种振动测量用电容式硅基MEMS加速度计

为了解决目前微电子机械系统(MEMS)加速度计在振动测量领域量程小和振动测量精度低等问题,基于绝缘体上硅(SOI)加工工艺,设计并制作了一款梳齿电容式MEMS加速度计。通过提高工作模态频率和干扰模态频差,提升了加速度计振动环境适应性;加速度计量程达到±50g,非线性度0.2%,横向灵敏度0.17%,分辨率优于0.5mg,体积9 mm×9 mm×2.7 mm,功率损耗30 mW。针对随机振动环境对加速度计的输出精度进行了实验验证,结果表明,MEMS加速度计与标准传感器的输出误差为2.69%,能够满足大部分工程应用需求。

基于波长调制系统的高灵敏度碳化硅光学MEMS加速度计

本文报道了一种基于双模波长调制的高频碳化硅(Silicon carbide,SiC)传感器及其在并光学微机电系统(Microelectromechanical systems,MEMS)中应用。基于碳化硅材料属性及双模分析,设计了一种适用于高频场的光学MEMS传感器,并利用ANSYS有限元分析(Finite element analysis,FEA)方法和严格耦合波分析(Rigorous coupled wave analysis,RCWA)方法,将其与其他高频传感器进行性能比较。结果表明,该光学传感器在整个操作测量范围内可提供2.2477(Δλ/Δa)的光学灵敏度、0.155 nm/g的机械灵敏度和几乎为零的交叉轴灵敏度,且第一谐振频率为40.035 kHz,线性测量范围为±129.03 g,传感系统灵敏度(Δλ/Δa)为0.3484 nm/g,工作带宽为35 kHz。

基于几何反弹簧结构的高分辨率MEMS加速度计

为了提高MEMS加速度计分辨率和灵敏度,提出并设计了一种基于几何反弹簧原理的新型MEMS加速度计结构。拟采用静电力将加速度计静态工作点设置在梁低刚度位置来提高灵敏度。首先通过理论计算和有限元仿真,分析了几何反弹簧结构实现准零刚度的原理,并优化了关键几何参数;其次基于免划片SOI工艺完成了MEMS芯片制作;最后搭建了开环测试电路进行测试验证。测试结果表明:施加25 V偏置电压后,加速度计灵敏度从46.3 mV/g提高至51.1 mV/g,线性度为0.99%。验证了静电偏置几何反弹簧结构通过降低刚度系数来提高加速度计的灵敏度的可行性。

±16g三质量块三轴MEMS电容式加速度计的设计

微电子机械系统(MEMS)惯性传感器(如加速计、陀螺仪)具有高性能、低功耗、低成本、集成度高、可靠性高、体积小等特点。但MEMS传感器交叉串扰仍较大,影响了加速度的测量。该文设计了一个量程为±16 g的三质量块三轴MEMS电容式加速度计结构,通过对所设计的结构进行静力学分析和模态分析,保证加速度计良好的抗过载能力。仿真结果表明,该结构实现了模态分离避免了模态干扰,且交叉灵敏度均小于0.3%,有效地降低了交叉串扰。

基于电容检测的高精度大量程MEMS加速度计设计

为满足系统在导航和倾角测量等领域对高精度、大量程加速度计的应用需求,设计了一种高精度、大量程微机电系统(MEMS)加速度计。加速度计敏感结构采用梳齿式结构,电容/电压(C/V)转换电路采用开关电容架构,通过斩波技术和相关双采样技术有效降低调理电路的1/f噪声。为提高系统线性度,模/数转换器(ADC)采用2阶1 bit Sigma-Delta架构,同时采用斩波技术降低ADC的失调及1/f噪声。本文设计采用0.18μm BCD工艺,调理电路面积为28 mm^(2)。测试结果表明:MEMS加速度计在±50 gn的量程下,零偏稳定性达到73.7μg,非线性度为69.3×10^(-6),总功耗110 mW。

芯片粘接对MEMS加速度计性能影响分析

研究了一种针对微电子机械系统(MEMS)变电容间隙式加速度计芯片粘接应力对零位输出影响的分析方法。通过建立加速度计的数学解析模型,从理论上推导出了电容变化量与间隙变化量的关系式。然后对影响间隙变化量的粘接应力进行了分析,得到了影响粘接应力的因素,并选取关键影响因素(粘结胶点直径)进行仿真分析。为了验证降低加速度计零位输出随温度变化的改进思路,分别装配了0.9 mm直径胶点和1.5 mm直径胶点粘接的加速度计进行了实验。实验结果表明,改进封装方案有效,采用直径0.9 mm胶点方案使零位输出变化量降低了75%。

基于深度学习的MEMS加速度计随机漂移补偿方法

为了有效地抑制MEMS加速度计的随机漂移,文中提出了一种将深度学习与神经网络相结合的方法补偿MEMS加速度计随机漂移。在循环神经网络(RNN)的基础上,建立长短期记忆神经网络(LSTM)模型,利用基于自适应性矩估计(ADAM)的优化算法对LSTM模型进行训练。结果表明,与传统的滤波算法相比,文中方法将MEMS加速度计补偿后的零偏稳定性、零偏不稳定性和加速度随机游走等性能指标降低了80%以上。通过实验验证了所提方法的有效性。

MEMS三轴加速度计误差标定与补偿方法研究

为了提高微机电系统(MEMS)三轴加速度计的测量精度,建立了MEMS三轴加速度计卡尔曼滤波模型,根据MEMS三轴加速度计的输出误差模型,推导了基于六位置法的误差补偿数学模型,并给出了数学模型中补偿参数的解算方法。最后基于自主研发的电子罗盘进行了实验验证,实验结果表明:经过卡尔曼滤波后,MEMS三轴加速度计输出噪声减小了74%;经过六位置法标定后,MEMS三轴加速度计的测量精度提升了1个数量级,解算得到的倾斜角精度由5.9°RMS提高到0.3°RMS。

MEMS加速度传感器动态误差补偿方法的研究

针对MEMS加速度传感器在实时检测中存在动态误差,现有动态误差补偿方法在实时性方面不能满足要求,提出了一种按频域抽取的快速傅里叶变换混合算法进行动态误差补偿的方法,首先分析建立MEMS加速度传感器输出的频率响应模型,其次利用动态误差补偿算法分析加速度的特征频率,实现对特征频率点的加速度进行补偿,通过对加速度传感器的硬件和软件设计,进行实验测试。实验测试结果表明,通过传感器软件数据处理,在0~1 000 Hz,经过动态误差补偿后的传感器在X轴、Y轴、Z轴方向,0~16 gn量程范围内,实时检测精度均可达到1%以内,实时性及检测的精度完全满足加速度测量要求。

基于反对称模态驱动的MEMS加速度计灵敏度优化方法

为了便于驱动谐振梁的反对称模态,提高加速度检测灵敏度,该文提出了一种分布式的电极驱动方式,利用分布式电极更易驱动谐振梁的反对称模态并检测信号。设计了弹性梁质量块系统,用作感知外部加速度的敏感质量,并将谐振梁作为测量加速度的敏感元件。建立了谐振梁前两阶动力学方程。实验测量了不同加速度下谐振梁一阶、二阶的频率变化。实验表明,二阶模态检测正向灵敏度比一阶模态检测正向灵敏度提高了49%,负向灵敏度提高了89%,且二阶模态品质因数是一阶模态品质因数的3.19倍。最后分析了偏置直流电压对灵敏度的影响:随着电压提高,正向加速度检测灵敏度提高,负向加速度检测灵敏度降低。

复杂应力条件下MEMS加速度传感器可靠性分析

针对MEMS加速度传感器在复杂应力条件下潜在的疲劳失效与断裂失效问题,提出了一种基于全概率公式的可靠性评估模型,完成了器件在振动环境、冲击环境以及振动-冲击耦合环境下的可靠性建模。模型包含Wiener过程和齐次泊松随机过程,分别描述器件在振动环境中的疲劳损伤以及器件遭受的随机冲击,进一步考虑了随机冲击的幅值大小对器件退化率的影响。通过器件在冲击应力下产生的疲劳损伤突增量,反映多失效模式间的相关性。对比分析了振动-冲击相互独立与相互耦合作用的可靠性模型,结果表明,振动-冲击相互耦合作用的可靠性模型评估结果更具有指导意义。