硅微阵列陀螺仪的仿真、设计与测试

为了提高硅微机械陀螺仪的精度和工作可靠性,提出了一种新的硅微阵列陀螺仪结构设计方案。该陀螺仪由4个质量块构成,采用半解耦结构设计,结构完全对称,驱动模态和检测模态的频率匹配性好。分析了硅微阵列陀螺仪的结构和工作原理,并利用ANSYS有限元软件进行了结构仿真,通过调节结构参数实现了各驱动模态与敏感模态固有频率的匹配。对阵列陀螺仪样品进行了测试,实验测试结果表明,驱动模态存在3个振型,同频反相振动的幅值最大,与仿真结果一致。     

硅微机械谐振式陀螺仪的技术研究

介绍了硅微机械谐振式陀螺仪的工作原理,设计了一种新型微机械谐振式陀螺,并用有限元方法进行了仿真,制造了一批样机,进行了初步的驱动特性实验.结果表明,该微机械谐振陀螺仪实际驱动模态的谐振频率与仿真值的最大误差小于6%,满足设计要求.     

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.     

硅微振动陀螺仪驱动器自激驱动研究

为了提高硅微机械陀螺仪的检测精度,稳定驱动振动速度的幅度和频率,采用了硅微机械陀螺仪自激驱动方式.该方式能够使驱动振动自动稳定在陀螺仪驱动模态的谐振频率上.同时,采用自动增益控制(AGC)保持恒定的驱动振动幅度.根据自激驱动电路原理和现有的陀螺样品,建立了陀螺仪驱动动力学方程的等效电路模型.设计、制作了自激驱动电路,仿真和实验结果表明该方法切实可行.     

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。     

基于自适应控制的硅微振动陀螺仪驱动电路研究

硅微振动陀螺仪驱动模态的稳定性对其性能及可靠性有着重要作用.自激驱动能够使单个驱动模态稳定谐振在固有频率上,但对于双驱动模态,由于微机械加工误差的影响,固有频率存在偏差,很难实现频率匹配.研究了基于自适应控制的硅微振动陀螺仪的驱动电路设计,通过固定频率信号驱动和自适应调谐实现双驱动模态的一致性.理论仿真和实验结果表明该设计切实可行.     

MEMS谐振陀螺实时自动模态匹配控制技术

为了消除温度对陀螺模态匹配的影响,提出了一种实现微机械谐振陀螺在温度-30～60℃内实时自动模态匹配控制方法。驱动模态和检测模态的谐振频率跟温度成线性关系,两轴的谐振频差与温度也成线性关系,该方法以驱动模态谐振频率作为温度参考而获得两模态谐振频差,根据谐振频差实时调节静电调谐电压,使得检测模态谐振频率与驱动模态谐振频率匹配。实验结果表明:检测谐振频率和驱动谐振频率在温度-30～60℃范围内,匹配误差不超过0. 3 Hz,验证了该方法的可行性、匹配精度,同时证明本文所采用的开环控制方案的有效性。     

微机械陀螺解耦控制技术的研究

研究微机械陀螺优化控制问题.由于微机械陀螺具有很严重的耦合误差,使得其精度和性能大大减弱.现有微机械陀螺解耦方法大都集中在结构解耦,受工艺和外界环境影响严重,且稳定性较差.针对上述问题,为了从源头消除耦合,在结构解耦的基础上提出了两种控制解耦方案即传统解耦方法和BP神经网络解耦方法,首先用传统解耦方法在建立其精确数学模型的基础上找到合适的解耦矩阵,使得驱动的输入和检测的输出为单一方向的运动,来实现控制解耦.然后用传统解耦后的数据来训练BP神经网络,进行解耦仿真,从而根本上消除耦合误差.仿真结果表明,上述控制解耦方案能根本上有效消除耦合,提高微机械陀螺解耦控制的鲁棒稳定性.     

新型双级解耦合微机械陀螺设计与仿真

在分析了微机械振动式陀螺机械耦合误差的基础上,提出了一种新型的双级解耦合的陀螺结构,可将驱动模态和检测模态完全隔离,以避免驱动对检测的同频干扰。通过在敏感质量和检测质量间用弹性连接来抑制和减小机械耦合误差。文中还对新结构进行有限元模拟,最后分析了系统频响。     

一种双线振动硅微机械陀螺仪驱动检测电路设计

以一种双线振动硅微机械陀螺仪为研究对象,设计了驱动、检测电路,达到了一定的性能要求。驱动模态使用自激振荡的闭环控制方式,使陀螺稳定工作在其固有频率上。在载波和驱动环节使用了一种AGC技术,实现了载波信号和驱动模态的幅度的高精度控制。使用二极管一次解调,简化了电路结构。检测部分使用了一种相位修正放大电路,有效减小了有用信号频率附近的幅相误差。     

驱动微梁形状对微陀螺仪耦合误差的影响分析

为研究微陀螺驱动微梁在加工误差下的微梁形状变化对正交耦合误差、模态耦合以及检测信号的影响,建立了驱动微梁在对角线梁宽误差下的有限元分析模型,采用有限元仿真分析和解析计算相结合的方法研究了U型梁一端梁长的变化对微陀螺正交耦合误差、模态耦合以及检测信号的影响.研究发现,当U型梁一端的梁长为另一端长度的二分之一左右时该类加工误差会引发非常严重的正交耦合误差和模态耦合现象,并对检测信号产生极大影响;当U型梁退化为直梁或者为等长梁的时候,对检测信号的干扰很小、正交耦合误差为零、模态耦合程度最小,而且两者的变化规律呈现正相关.适当地加大单自由度微陀螺驱动模态和检测模态的频率差不仅可增加微陀螺的带宽还可减小耦合的影响.     

An x-axis single-crystalline silicon microgyroscope fabricated by the extended SBM process

A high-aspect ratio, single-crystal line silicon x-axis microgyroscope is fabricated using the extended sacrificial bulk micromachining (SBM) process. The x-axis microgyroscope in this paper uses vertically offset combs to resonate the proof mass in the vertical plane, and lateral combs to sense the Coriolis force in the horizontal plane. This requires fabricating vertically and horizontally moving structures for actuation and sensing, respectively, which is very difficult to achieve in single-crystalline silicon. However, single-crystalline silicon high-aspect ratio structures are preferred for high performance. The extended SRN/I process is a two-mask process, but all structural parts and combs are defined in one mask level. Thus, there is no misalignment in any structural parts or comb fingers. In this extended SBM process, all vertical dimensions of the structure, including the comb height, vertical comb offset and sacrificial gap, can be defined arbitrarily (up to a few tens of micrometers). For electrical isolation, silicon-on-insulator (SOI) wafers are used, but the inherent footing phenomenon in the SOI deep etching is eliminated and smooth structural shapes are obtained, because the SBM process is used. In the fabricated x-axis microgyroscope, the lower combs used to vibrate the proof mass are vertically offset 12 /spl mu/m from the upper combs. The fabricated x-axis microgyroscope can resolve 0.1 deg/s angular rate, and the measured bandwidth is 100 Hz. The reported work represents the first x-axis single-crystalline silicon microgyroscope fabricated using only one wafer without wafer bonding. We have previously reported several versions of z-axis microgyroscopes and x-, y-, and z-axis accelerometers, using the SBM process. The results or this paper allow integrating x-, y-, and z-axis microgyroscopes as well as x-, y-, and z-axis microaccelerometers in one wafer, using the same mask and the same process.     

硅微陀螺仪的误差分析

以z轴硅微陀螺仪为研究对象,对加工误差产生的误差信号进行了分析.由于加工误差,使得陀螺仪结构不对称,主要表现为支承梁不对称、梳齿间距不等,产生了不等弹性、阻尼不对称以及力不平衡这三种现象.以动力学方程为基础,分析了不等弹性和阻尼不对称产生的误差信号;以静电理论为基础,分析了驱动梳齿和敏感梳齿间距不等时产生的误差信号.分析结果表明,这些误差信号包含了正交耦合误差和与有用信号同相位的误差信号.最后,介绍了一种减小正交误差的方法,并进行了仿真.     

微机械振动陀螺模态耦合误差分析与激光修形方法研究

较大的模态耦合误差严重影响陀螺仪的零偏稳定性。研究了一种微机械振动陀螺仪的模态耦合误差形成机理,仿真分析了结构加工误差对模态耦合误差的影响规律。仿真结果表明:振动结构支撑梁上的加工误差是引起结构刚度不对称并产生模态耦合误差的主要因素,在与该加工误差对称的位置去除相应的材料可以减小甚至消除模态耦合误差。采用紫外激光微细加工技术,对微陀螺样机进行了结构平衡实验,激光修形后在没有输入角速度时,微陀螺样机模态耦合误差信号的峰峰值从2.88 V降低到0.24 V,取得了明显的修形效果。     

于二次谐波检测的电容式微惯性器件频率响应测试方法研究

针对电容式微惯性器件信号微弱、耦合噪声大的特点,提出了一种基于二次谐波检测的频率响应测试方法,详细介绍r该测试方法的基本原理,设计了基于此方法的频率响应测试系统,分析了测试系统中存在的误差,以本实验室研制的电容式微陀螺为测试对象,对该方法和传统的一次谐波检测方法进行了对比,结果表明,该方法能够有效地减小电路中耦合噪声对测试结果的影响,提高频率响应测试精度.     

High-Q single crystal silicon HARPSS capacitive beam resonators with self-aligned sub-100-nm transduction gaps

This paper reports on the fabrication and characterization of high-quality factor (Q) single crystal silicon (SCS) in-plane capacitive beam resonators with sub-100 nm to submicron transduction gaps using the HARPSS process. The resonating element is made of single crystal silicon while the drive and sense electrodes are made of trench-refilled polysilicon, yielding an all-silicon capacitive microresonator. The fabricated SCS resonators are 20-40 /spl mu/m thick and have self-aligned capacitive gaps. Vertical gaps as small as 80 nm in between 20 /spl mu/m thick silicon structures have been demonstrated in this work. A large number of clamped-free and clamped-clamped beam resonators were fabricated. Quality factors as high as 177000 for a 19 kHz clamped-free beam and 74000 for an 80 kHz clamped-clamped beam were measured under 1 mtorr vacuum. Clamped-clamped beam resonators were operated at their higher resonance modes (up to the fifth mode); a resonance frequency of 12 MHz was observed for the fifth mode of a clamped-clamped beam with the fundamental mode frequency of 0.91 MHz. Electrostatic tuning characteristics of the resonators have been measured and compared to the theoretical values. The measured Q values of the clamped-clamped beam resonators are within 20% of the fundamental thermoelastic damping limits (Q/sub TED/) obtained from finite element analysis.     

A self-aligned fabrication method of dual comb drive using multilayers SOI process for optical MEMS applications

A novel method for fabricating a self-aligned electrostatic dual comb drive using a multi-layer SOI process is developed. The present method utilizes four aligned masks, greatly simplify the existing SOI-MEMS fabrication methods in manufacturing optical MEMS devices. Here, the actuating structure consists of fixed combs and moving combs that are composed of single crystal silicon, nitride and polysilicon. One mask is used to provide a deep etching to etch polysilicon, nitride and single crystal silicon respectively. The nitride separates polysilicon and single crystal silicon and provides an additional dielectric for the purpose of producing bi- directional motion upon applying electrostatic forces. A dual comb drive actuator with optical structures was fabricated with the developed process. The actuator is capable of motion 250 nm downward and 480 nm upward with 30 V applied voltage at 4 kHz frequency. The dynamic characteristics of the first and the second resonant frequency of the dual comb-drive actuator are 10.5 kHz and 23 kHz respectively. Experimental results indicated that the measured data agreed well with simulation results using the ANSOFT Maxwell^® 2D field simulator, ANSYS^® and Coventor Ware^®.     

基于激励-校准法的硅微陀螺仪模态匹配控制电路研究

提出了一种基于激励-校准法的硅微陀螺仪实时模态匹配控制电路,利用了检测模态的幅度响应信号关于其谐振频率对称的特点,采用双边激励信号激励检测模态,通过比较双边信号的响应幅度大小来获得相应的调谐电压,实现模态匹配.介绍了静电负刚度调谐原理;然后设计了基于激励-校准法的硅微陀螺仪实时模态匹配控制方案,并分析了该法的误差来源;在Simulink环境下搭建了模态匹配控制电路模型,验证了该方案的可行性;最后,设计了基于FPGA的自动模态匹配控制电路.实验结果表明,相比于模态不匹配情况,模态匹配后的陀螺仪零偏稳定性系数由1.69 °/h降低到0.42 °/h,静态性能提升了4.02倍;角度随机游走系数由0.046 °/ h降低到0.0195 °/ h,静态性能提升了2.36倍.     

z轴硅微陀螺仪高精度闭环驱动研究

提出了一种z轴硅微陀螺仪高精度闭环驱动方案.该方案实现了闭环驱动的相角和增益条件的解耦;对相角进行了优化控制,消除了驱动频率和驱动模态固有频率的相对频差影响;利用闭环回路中直流控制量与驱动力间的非线性关系,实现闭环自激控制.试验结果表明,1 h内,驱动频率变化的均方差为0.009 Hz,相对变化量为2.2ppm(1ppm=10-6);驱动幅度变化的均方差为0.002 5 mV,相对变化量为15ppm;驱动信号的噪声功率谱密度低于-100 dB.由此可见,本方案使陀螺仪驱动性能得到了极大提高.     

Research of a novel stereoscopic symmetrical quadruple hair gyroscope

This paper presents a novel stereoscopic symmetrical quadruple hair gyroscope (SSQHG) which is distinguished from the conventional flat structures to achieve better angular rate measurement performance. A symmetrical device architecture is designed to realize the differential detection of Coriolis force, thereby effectively eliminate the common mode interference. Four stereoscopic hair posts are adopted to increase the quality of the lumped inertia masses, so as to enhance the measurement sensitivity. A simplified mass-spring-damper model of idealized SSQHG is established and verified by a modal simulation to synthetic analysis the motion modal. A set of finite element method simulations including modal distribution simulation and harmonic response simulation are implemented to acquire accurate vibration information and to identify the structure parameters quantitatively. A micromachining procedure based on the standard deep dry silicon on glass is adopted to fabricate the proposed micro-gyroscope. The frequency response experiments indicate that the vacuum packaged prototype has a drive mode frequency of 536.2 Hz with a quality factor of 1319.7 and a sense mode frequency of 535.7 Hz with a quality factor of 1334.5. An analog closed-loop driving circuit is designed to realize the self-excited oscillation of SSQHG and an open-loop sensing circuit is designed to extract the Coriolis force signal. The preliminary experimental results demonstrate that the fabricated SSQHG prototype exhibits an angular rate sensitivity of 16.03 mV/°/s and a bias instability of 16.26°/h at room temperature.