Thermal effect on the dynamic behavior of nanobeam resonator assuming size-dependent higher-order strain gradient theory

Microsystem Technologies - The temperature change and size scale dependent effects on the dynamical behaviors of the Carbon nanotube (CNT)-based nano-resonator are investigated in this work. The...     

一种Z轴微机械陀螺的自解耦方法研究

在分析了微机械陀螺机械耦合误差产生原因的基础上,提出了一种解耦梁方案,可以从结构上消除振动式微机械陀螺敏感模态对驱动模态的耦合影响;基于该解耦梁方案设计了一种新型的Z轴微机械陀螺结构.分析表明,该陀螺结构消除了敏感模态对驱动模态的耦合影响,实现了解耦设计的目的.     

A dual-axis MEMS capacitive inertial sensor with high-density proof mass

This paper reports a novel dual-axis microelectromechanical systems (MEMS) capacitive inertial sensor that utilizes multi-layered electroplated gold. All the MEMS structures are made by gold electroplating that is used as a post complementary metal-oxide semiconductor (CMOS) process. Due to the high density of gold, the Brownian noise on the proof mass becomes lower than those made of other materials such as silicon in the same size. The single gold proof mass works as a dual-axis sensing electrode by utilizing both out-of-plane (Z axis) and in-plane (X axis) motions; the proof mass has been designed to be 660 μm × 660 μm in area with the thickness of 12 μm, and the actual Brownian noise in the proof mass has been measured to be 1.2 \({\upmu}{\text{G/}}\sqrt {\text{Hz}}\) (in Z axis) and 0.29 \({\upmu}{\text{G/}}\sqrt {\text{Hz}}\) (in X axis) at room temperature, where 1 G = 9.8 m/s². The miniaturized dual-axis MEMS accelerometer can be implemented in integrated CMOS-MEMS accelerometers to detect a broad range of acceleration with sub-1G resolution on a single sensor chip.     

一种MEMS陀螺仪的标定方法研究

微机电系统(MEMS)陀螺仪的测量误差是影响微惯性导航系统精度的重要因素.为了提高微惯性导航系统的精度,提出了一种利用三轴转台完成MEMS陀螺仪的标定方法.根据MEMS陀螺仪的误差模型,设计了标定试验方案和误差模型参数的辨识方法,并通过小波阈值去噪的方法对陀螺的输出数据进行去噪处理.试验与仿真对比分析结果表明:经误差补偿和去噪后MEMS陀螺仪的测量精度提高1～2个数量级,同时验证了该标定方法的正确性、有效性.     

Study on frequency stability of a linear-vibration MEMS gyroscope

Thermal-dependent frequency stability of a linear-vibration gyroscope, based on elastic theory of thin plate, is studied. As an elastic structure, the resonant frequency of the gyroscope is determined by the secant coefficient of thermal expansion of the material in which the gyroscope is made. For decreasing the frequency variation under different temperatures, the gyroscope can be changed in its structure to eliminate the thermal stress caused by mismatch of materials the gyroscope made in. Two gyroscopes with straight-beam and folded-beam supporting respectively are designed and analyzed. When replacing straight-beam by folded-beam in the gyroscope, the frequency variation of the gyroscope decreases. The two structures then are manufactured for testing. The testing shows the same result as analysis.     

Dynamics and control of a MEMS angle measuring gyroscope

This paper presents an algorithm for controlling vibratory MEMS gyroscopes so that they can directly measure the rotation angle without integration of the angular rate, thus eliminating the accumulation of numerical integration errors incurred in obtaining the angle from the angular rate. The proposed control algorithm consists of a weighted energy control and a mode tuning control. The weighed energy control compensates unequal damping terms and keeps the amplitude of oscillation constant in an inertial frame by maintaining the prescribed total energy. The mode tuning control continuously tunes mismatches in spring stiffness in order to maintain a straight line of oscillation for the proof mass. The simulation results demonstrate the feasibility of the control algorithm and the viability of the concept of using a vibratory gyroscope to directly measure rotation angle.     

MEMS陀螺误差辨识与补偿

由于制造工艺等原因,MEMS陀螺的随机漂移非常大,严重影响了系统的性能.通过自制的基于MEMS的捷联惯导系统的相关实验,对MEMS陀螺的确定性误差和随机误差分别进行了辨识和补偿.完成确定性误差补偿,对MEMS陀螺随机误差进行了时间序列分析,并建立了AR模型,根据所选模型参数建立了随机误差的系统方程,采用经典卡尔曼滤波进行随机误差补偿.实验结果说明:无论是静态下还是动态下,补偿后信号的方差都大大下降,说明了滤波效果较为明显,具有一定的工程应用价值.     

微机械陀螺仪模态分析

利用计算机软件对有限元法构建的微机械陀螺仪模型进行分析可以掌握其各种参数。根据静电梳状驱动结构,设计符合性能指标的陀螺仪结构,并利用有限元分析法借助ANSYS软件对陀螺仪进行模态分析,从而得出陀螺仪的驱动模态和敏感模态,为已经设计的结构提供分析和修正的参考,从而提高微机械陀螺仪设计结构的品质因数。     

MEMS gyroscope control system using a band-pass continuous-time sigma-delta modulator

This paper presents a MEMS gyroscope control system of using a high-order band-pass continuoustime sigma-delta modulator.Compared with a low-pass discrete-time sigma-delta modulator based solution,the band-pass modulator can considerably decrease the sampling frequency;moreover,the continuous-time architecture has an obvious advantage on PCB prototyping and shorter lead time of the implementation in hardware.System level simulations using MATLAB/Simulink show the proposed sixth order sigma-delta modulator can achieve a high SNR of 100 dB for an angular rate input with an amplitude of 200/s and a frequency of32 Hz.A PCB circuit implementation is simulated using Orcad/PSpice to analyze the stability,and implemented in hardware.Measurement of the power spectral density of the output bitstream reveals a noise floor of90 dBV/Hz1/2.The prototype is tested on a rate table with an angular rate input,verifying that the principle of the approach of using an electro-mechanical band-pass sigma-delta modulator control system for a MEMS gyroscope.     

Matching mechanical response for a MEMS vibratory tuning fork gyroscope

Microsystem Technologies - This paper introduces the configuration of the MEMS tuning fork gyroscope with the connecting diamond-shaped frame to achieve the anti-phase mode in the driving...     

A new adaptive fractional sliding mode control of a MEMS gyroscope

Microsystem Technologies - The Micro-Electro-Mechanical System (MEMS) gyroscope is a well-known device, which has been widely used in medicine due to its small size. In this study, a new adaptive...     

Sensitivity analysis of an in-plane MEMS vibratory gyroscope

Microsystem Technologies - This paper aims to put forward a detailed sensitivity analysis of an in-plane MEMS gyroscope with respect to various performance criteria that are very critical for use...     

A new hybrid robust control of MEMS gyroscope

To control microelectromechanical systems (MEMS) gyroscope axis, we propose and investigate a new robust sliding mode controller (NRSMC). The sliding surface in the phase space converges to the equilibrium point within a finite period from any initial state. However, the main drawback of this control system is the chattering phenomenon, which is undesirable for the MEMS system. To solve this problem, we suggest a novel hybrid control system which improves trajectory tracking and eliminates the chattering. The dynamic stability of NRSMC against external disturbances is proved by applying the Lyapunov theory. The effectiveness of the proposed control method is verified by numerical simulation with a random noise applied to demonstrate the robustness of the proposed control system.

     

MEMS陀螺振动特性试验技术

对于MEMS振动陀螺来说,找到一个快速有效的方法来评估其结构参数是非常重要的,比如谐振频率和阻尼系数,应根据微机械陀螺设计和制作的不同阶段,从测试精度、测试速度和试验方便程度等方面考虑,采用不同的方法进行动态试验。本文给出了一种能够判断MEMS器件振动特性的可靠的电测试系统,并通过分析和实验比较了几种微机械陀螺振动系统传递函数的快速测定方法,分析讨论了微机械陀螺振动系统测试方法和数据处理等问题。     

Electrostatic fringing-fields effects on the structural behavior of MEMS shallow arches

Microsystem Technologies - In this paper, we investigate the effects of electric fringing-fields on the structural behavior of a MEMS shallow arch. We consider the Galerkin method-based...     

基于介观压光效应的MEMS陀螺研究

依据介观压光效应原理,设计出了一种新型高灵敏谐振式MEMS陀螺,其利用镜像异质三周期光子晶体的介观压光效应代替传统压阻式微陀螺中的力敏电阻器,当光子晶体受轴向应力作用时,其透射率随之发生变化,因此,通过检测透射光强可解算出输入角速度的大小.陀螺结构采用4对梳齿电容驱动,驱动模块与检测模块相互独立,其具有耦合效应小,机械灵敏度高的特点.经数值计算与仿真分析,得到该微陀螺频率匹配率为0.6％,透射率灵敏度达到73μcd/(°)/s,证明了其频率匹配良好,可实现高灵敏度的角速度的测量.     

MEMS陀螺正交误差分析与仿真

针对MEMS陀螺由于机械耦合引起的正交误差,建立了包含误差的MEMS陀螺动力学方程,在开环检测和闭环检测情况下,分别对正交误差进行了分析,并通过相关检测技术抑制正交误差对陀螺性能的影响,提取出角速度信息.运用Simulink对陀螺进行了建模仿真,仿真结果表明:在开环检测和闭环检测情况下都能够有效消除正交误差的影响,由此验证了理论分析的正确性.     

MEMS陀螺漂移误差建模与滤波

MEMS陀螺漂移误差直接影响光电稳定跟踪平台伺服机构的控制精度.针对MEMS陀螺随机漂移误差慢时变、弱非线性、难以准确补偿的特点,基于随机序列时序分析法的基本原理,对预处理后的MEMS陀螺漂移残差信号进行建模,并根据模型对残差信号进行Kalman滤波.结果显示滤波前后信号的方差提高了1到2个数量级,表明有效抑制了漂移误差,提高了MEMS陀螺的精度.     

MEMS陀螺随机误差模型研究

对MEMS陀螺随机误差进行了实验测试及研究,选取状态方程模型,基于近年来发展起来的随机系统子空间辨识方法,对MEMS陀螺随机误差进行建模,结果与Allan方差方法分析的噪声特性相符合,经与ARMA等模型比较,在同等性能下,所建模型具有阶次低的优点,更加适合于实时在线优化估计器.所提方法可以不加修改直接应用于对多轴陀螺的处理.     

Novel self-compensation method to lower the temperature drift of a quartz MEMS gyroscope

A new self-compensation method is proposed in this paper. The impedance of a quartz tuning fork changes along with the temperature. A digital driving circuit is designed so that the frequency can be adjusted by controlling the phase. The relationship between the driving amplitude and the temperature is captured in a digital circuit, which can reflect the temperature information. As the relationship is nonlinear, after third-order fitting, the temperature has a precision of 2.356 °C. Finally, the bias stability is optimized and the drift decreases to 1.7 %.