微机械陀螺的仿真与优化

微机械陀螺依靠振动模态频率来测量旋转角速度,通常微机械结构的振动模态相当复杂。虽然已有很多文章研究了如何调节驱动模态和敏感模态以获得最大的敏感度,却很少有人分析微机械陀螺的振动模态。振动模态与陀螺结构的设计参数有极大的关系,这些参数包括陀螺检测质量的尺寸、支撑系统的类型和尺寸,以及用以制造陀螺主体的多晶硅的残余应力。研究了一个静电驱动、电容检测、敏感垂直轴角速度的陀螺(也称平面陀螺)。同时,用有限元法分析法对微机械陀螺的结构进行了分析。     

Design and fabrication of a micromachined gyroscope with high shock resistance

In this paper, a tuning fork gyroscope designed for high-g shock environments is presented. This micro gyroscope with 10 kHz designed working frequency is composed of double symmetrical frame structures that are connected by middle coupling beams. Two level elastic stoppers were designed in order to improve the shock resistance of the gyroscope. Slots were etched to reduce damping in the inner bonding regions. By bulk silicon micromachining technology, the gyroscope was fabricated on a 300 μm thickness silicon wafer. The working frequencies of the gyroscope on the driving and sensing modes are 10,240 and 11,160 Hz, respectively. Shock experiments to bare chips indicate that the shock resistance of the gyroscope along X-axis is 15,000 g, Y-axis is 14,000 g and Z-axis is 11,000 g.     

一种高灵敏度硅微机械陀螺的设计与制造

设计与制造了一种高灵敏度的硅微机械陀螺。陀螺用静电来驱动,用连接成惠斯顿电桥的压阻式力敏电阻应变计来检测。主梁、微梁 质量块结构实现了高灵敏度。比较硬的主梁提供了一定的机械强度,并且提供了高共振频率。微梁很细,检测时微梁沿轴向直拉直压。力敏电阻应变计就扩散在微梁上,质量块很小的挠动就能在微梁上产生很大的应力,输出很大的信号。5V条件下,陀螺检测部分的理论灵敏度达到27.45mV/gn。压阻式四端器件用来监测驱动振幅,可以反馈补偿压阻的温度系数。检测模态的Q值达260使陀螺能在大气下工作。陀螺利用普通的n型硅片制造,为了刻蚀高深宽比的结构,使用了深反应离子刻蚀(DRIE)工艺。     

Design,fabrication and characterization of a low-noise Z-axis micromachined gyroscope

This paper presents the design, fabrication and characterization of a low-noise Z-axis micromachined gyroscope. A triple-mass scheme is adopted to obtain a decoupled mode and matched vibration structure. The gyroscope was fabricated based on a 30-μm silicon on insulator wafer. A DRIE, lag-effect-based, dicing-free process was used to easily and rapidly create the gyroscope devices without requiring normal dicing. The fabricated gyroscopes were vacuum packaged (pressure of approximately 2,000 Pa) and tested. The measured power spectral density of the noises is as low as 17.5 μV/√Hz, and the resolution of the fabricated gyroscope is 7.1 × 10–4°/s/√Hz (2.52°/h/√Hz).     

Design of a novel lower-noise tunneling magnetoresistance micromachined gyroscope

Microsystem Technologies - The core technology behind micromachined gyroscopes is the detection of the weak Coriolis force, the noise level of which by conventional methods has reached its limit....     

三轴微机械陀螺仪的结构设计与仿真

提出了一种适应国内加工条件的三轴微陀螺仪,依据三轴陀螺的结构和工作原理,利用ANSYS有限元仿真软件对三轴陀螺的设计进行了计算和仿真.在此基础上,通过调节结构参数实现各轴驱动模态与敏感模态固有频率的匹配以提高各轴的灵敏度.最后介绍了加工所采用的工艺.     

微机械陀螺管芯测试方法

采用低分布参数陶瓷探针卡和卡上前置放大器的静电驱动测试方案,解决了微机械陀螺管芯测试中分布参数的影响问题,测得准确的频率特性,获得应用、评估中必需的谐振频率、品质因数(Q值)等参数。在将管芯与测试电路分离、结合的过程中,四维精密位移台发挥了良好的作用。显微视频系统使观察、记录更加准确方便。虚拟仪器技术的应用提高了测试过程的自动化程度。系统为快速剔除不合格产品、测试评估各项性能指标提供了快速有效途径,在促进微机械陀螺技术发展与产业化过程中必将发挥重要的作用。     

Electrostatic correction of structural imperfections present in a microring gyroscope

This paper describes a procedure for identifying mass and stiffness imperfections present in a microring gyroscope. In general mass and stiffness imperfections will be present as a result of fabrication variances and will contribute to mistuning of the gyroscope. Both mass and stiffness imperfections are treated as perturbations of the ideal isotropic mass and stiffness. The mass and stiffness perturbations are combined to form a structural imperfection, which is shown to be determinable from Nyquist plots of the frequency response functions. An analysis of electrostatic "tuning" is presented and demonstrates that the nonlinear negative spring component produced from a particular arrangement of capacitive electrodes is capable of removing such structural imperfections. If uncorrected the structural imperfections would otherwise result in anisoinertia and anisoelasticity. A comparison between the theoretically predicted tuning voltage and the experimentally derived value is made and shown to be in agreement. The major advantage of electrostatic tuning is that it may be implemented on-chip during operation thus providing active tuning. This is in contrast to the trimming techniques employing laser ablation or focussed ion beam, which may only be done prepackaging.     

一种双自由度双级解耦微机械陀螺的特性分析

为了降低微机械陀螺的机械耦合和改善工作稳定性,提出了一种新颖的双自由度双级解耦微机械陀螺.建立并求解了该陀螺的动力学方程,并从理论上分析了陀螺的系统特性.利用数值求解工具MATLAB模拟了陀螺的幅频特性,结果表明当品质因子从50变化到1 000时,平坦区带的幅度和相位变化很小.理论和模拟均证实了该陀螺在选择适当的工作区带时,能获得较高的工作稳定性.     

Structure design and fabrication of a novel dual-mass resonant output micromechanical gyroscope

A novel dual-mass resonant output micromechanical gyroscope is proposed which utilizes resonant sensing as the basis for Coriolis force detection instead of displacement sensing. It can overcome the shortcoming of single-mass resonant output micromechanical gyroscope and can reduce the common mode acceleration error by using a dual-mass topology structure and lever differential mechanism. The structure and operating principle of the device are introduced. Moreover, some important theoretical analyses of the gyroscope are provided in detail. The analytical results have shown that the resonant frequencies of vibrating mass and double-ended tuning fork resonators are 3.153 and 62.853 kHz. The device has a frequency sensitivity of 12.535 Hz/deg/s and a mechanical noise floor of $ 7.957\deg /{\text{h}}/\sqrt {{\text{Hz}}} A novel dual-mass resonant output micromechanical gyroscope is proposed which utilizes resonant sensing as the basis for Coriolis force detection instead of displacement sensing. It can overcome the shortcoming of single-mass resonant output micromechanical gyroscope and can reduce the common mode acceleration error by using a dual-mass topology structure and lever differential mechanism. The structure and operating principle of the device are introduced. Moreover, some important theoretical analyses of the gyroscope are provided in detail. The analytical results have shown that the resonant frequencies of vibrating mass and double-ended tuning fork resonators are 3.153 and 62.853 kHz. The device has a frequency sensitivity of 12.535 Hz/deg/s and a mechanical noise floor of 7.957deg/\texth/?{\textHz} 7.957\deg /{\text{h}}/\sqrt {{\text{Hz}}} in air. The finite element simulation results verify the accuracy of analytical algorithms. The common mode acceleration error of device can be reduced by 97.6%. The device is fabricated by SOG (Silicon on Glass) micro fabrication technology. Some important performances are measured by experimental method. The micromechanical gyroscope can be used to estimate the rotation rate by further implementing the signal processing electronics.     

Effects of environmental temperature on the performance of a micromachined gyroscope

This paper presents the modeling of the detection capacitance analysis for a tuning fork vibratory microgyroscope fabricated by the bulk silicon micromachining technology. The dynamic characteristics of the detection capacitance of the microgyroscope are calculated based on the model. Then the effects of environmental thermal fluctuations on the microgyroscope are considered. Non-linear analysis and numerical simulations show that the frequencies and output of the microgyroscope have slight deviations when the microgyroscope works at different environmental temperature. The deviations of the frequencies and dynamic characteristics are calculated accurately, which provides a reference for the design of temperature compensation method and robust structural design for the microgyroscope.     

Optical detection of the Coriolis force on a silicon micromachined gyroscope

In this paper, we report on the optical characterization of a micromachined gyroscope prototype for automotive applications, by means of feedback interferometry. In order to directly detect the rotation-induced Coriolis force, we have developed a compact and stable interferometric setup, which has been positioned inside a small vacuum bell, mounted on a rotating table. By this setup, which has a noise limit of the order of 10/sup -11/ m/(Hz)/sup 1/2/, we have measured the gyro responsivity curve, demonstrating the feasibility of the optical interferometric detection of the in-plane response of a MEMS sensor. In addition, we have carried out the full mechanical characterization of the device at different pressures, and we have performed the matching of the gyro resonance frequencies by the interferometric monitoring. Our gyro had a resonance frequency of 3986 Hz for both axes after tuning; at a pressure of 7 10/sup -2/ torr, the quality factor were Q=18000 for the driving axis and Q=1800 for the sensing axis, while the measured responsivity was 7 10/sup -10/ m/(/spl deg//s). The optical characterization represents an important feedback to the designer and is especially powerful in the case of prototypes for which the on-board electronics is not yet available.     

压电微固体模态陀螺的安装技术

压电微固体模态陀螺（ PMMG）利用压电PZT长方体的某高阶共振模态作为参考振动,是一种抗冲击、抗震动能力强的新型全固态陀螺。获得优化的参考振动振型对提高陀螺性能至关重要,但是大多数文献都没有涉及到封装对参考振动的影响。利用有限元方法（ FEM）分析了压电振子安装时支撑点位置与接触面积对参考振动的影响,分析结果表明：相对于接触面积的变化,支撑点位置的变化对陀螺参考模态的影响更大。该研究结果为压电微固体模态陀螺的安装方法提供了理论基础。     

Interface and control electronics for a bulk micromachined capacitive gyroscope

An interface and control electronics have been designed and implemented for a bulk micromachined capacitive gyroscope. The system is composed of an application-specific integrated circuit (ASIC) that implements the analog parts of the system and a field-programmable gate array (FPGA) chip that implements the digital signal processing part. Both the system architecture and details of the different circuit blocks will be discussed. The system utilizes phase coherent demodulation to resolve the final output signal. In a typical implementation, phase delay and phase noise in the clock generation cause the signal quality to degrade. A method for correcting these errors will be introduced. A prototype of a microelectromechanical gyroscope has been realized and characterized. The measurement results show that the gyroscope achieves 0.042°/s/  spot noise and 51.6-dB signal-to-noise ratio (SNR) over the 40-Hz bandwidth with a 100°/s input signal.     

Designing of a micromachined gyroscope system with a closed-loop DC biased interface ASIC

In this paper, a micromachined gyroscope system composed of a vibratory gyroscope with its in- terface ASIC is presented. The system adopts a DC sensing method to detect the capacitive motion, which is insensitive to the mismatch of the gyroscope capacitors and can eliminate high frequency signals from the chip. Therefore it offers a commendable noise performance with simplified topology. Low noise design can be achieved by a continuous-time charge sensitive amplifier with the input-referred noise voltage of 9.833 nV/rtHz at 10 kHz. A novel high voltage （HV） buffer is adopted in the drive mode to strengthen its drive signal, so that the common-mode voltage of it is made at 5 V that is compatible with the gyroscope. The HV buffer utilizes two sets of power supply to achieve both good noise performance and HV output. The ASIC chip is fabricated in the 0.35 μm 2P4M BCD HV process, and is 2.5×2.0 mm2 in dimension. The test results prove that the system achieves a stable closed-loop oscillation in the drive mode. Furthermore, the in-phase demodulation result of the gyroscope system achieves a nonlinearity of 0.14% within the sense range of 0° 500°/s.     

CMOS-MEMS体硅陀螺的系统仿真

体硅MEMS和CMOS电路的单片集成技术是提高传感器性能的有效途径,但是集成技术会对陀螺的设计和CMOS电路的设计提出更高的要求。本文通过建立CMOS-MEMS体硅陀螺的等效电学模型,实现了对CMOS-MEMS体硅陀螺的系统级仿真。通过系统仿真,陀螺的结构部分、电路部分、集成产生的寄生效应以及工艺误差得到了有效的分析,从而能够了解它们相互之间的影响,更好的指导CMOS-MEMS体硅集成器件的设计。     

Modeling and simulation of levitation control for a micromachined electrostatically suspended gyroscope

This paper presents a novel micromachined electrostatically suspended gyroscope (MESG) based on non-silicon micro electro mechanical systems technology, which can measure dual-axis angular velocity and tri-axis linear acceleration. The position of the rotor is detected capacitively and controlled electrostatically. In order to levitate the rotor along the Z axis, a levitation control model based on integrated control strategy for the MESG is presented. The damping coefficient is calculated by finite element analysis and deduced by analytical solution. According to the analysis of the levitation control force of the rotor, a three-degree-of-freedom close-loop control model is constructed. The theoretical relationship between the proportional integral derivative control parameters and stiffness properties is deduced. Initial levitation simulation result shows that the control principle is reasonable, which shows quick-response performance and global stability. Furthermore, digitally controlled levitation circuits have been designed.     

微陀螺模态特性的参数化分析方法

模态分析是微陀螺结构设计的重要环节,针对一种采用L形截面悬臂梁支撑的微陀螺结构,提出了参数化的模态分析方法.建立了微陀螺的参数化模型,以VC作为封装ANSYS的APDL命令流的工具,开发了微陀螺参数化的模态分析模块.利用该模块研究了微陀螺模态频率随主要结构尺寸变化的规律,发现对模态频率影响较大的是硅结构的厚度和支撑梁的...