基于光流技术的MEMS器件平面微运动测量

为测量MEMS谐振器周期运动过程中各时刻不同相位的运动特性及其动态参数,提出利用光学测量方法,设计基于机器微视觉的MEMS动态分析仪.其实现机理是基于频闪成像原理获得MEMS谐振器一个周期内所需相位的清晰运动图像,结合光流技术对MEMS谐振器的运动序列图像做二维运动估计,从而得到其动态特性参数,为MEMS器件的设计提供重要参考.具有非接触性、测量精度高的特点.实验结果表明,该系统的测量重复性达7.1nm,能够很好地描述微谐振器的动态特性.     

激光差动多普勒的信号处理电路设计

随着微机电系统(MEMS)技术的迅速发展,对器件运动性能检测的需求日益迫切.采用激光差动多普勒测量技术能准确可靠地对MEMS器件进行动态特性测试.本文介绍了激光差动多普勒系统的信号处理电路的设计,主要包括放大电路、相敏检波电路和滤波电路.放大电路能将40 MHz频率信号放大100倍,相敏检波电路滤除了高频信号,分离出多普勒频移信号,滤波电路进一步滤除相敏检波电路输出信号中的载波信号和高频噪声.本电路设计最终实现了从光路系统输出的高频信号中提取多普勒信号.     

基于FPGA的MEMS测量控制系统的设计

基于频闪显微干涉(stroboscopic interferometer vision system,SIVS)技术,提出了一种MEMS三维动态测量的同步控制系统.在该系统中,频闪的参数通过有USB功能的MCU从PC配置到FPGA中,然后由FPGA分别控制测量系统中的声光调制器、MEMS驱动器、微动平移台和千兆网相机.结合开发的应用软件,可以实时测量MEMS的运动.计算表明,使用该系统所能测量的MEMS的理论最高周期运动频率为1 MHz.实验证明这种方法行之有效.     

基于卡尔曼滤波器的姿态角测量系统设计

针对动态环境下载体的姿态测量,以无人机的航姿测量系统小型化为背景,给出了一种采用MEMS惯性器件构成的姿态角测量系统。系统采用新型32位ARM Cortex-M3内核微控制器STM32F103ZET6作为控制处理单元,传感器采用ADXL345加速度计、L3G4200D陀螺仪和HMC5883磁阻传感器。对于MEMS器件精度低,数据易发散的问题,采用卡尔曼滤波器实时将加速度计、陀螺仪和磁强计的数据进行融合,计算负担小,实时性好。实验结果表明,该姿态测量系统在静态和动态环境下都能够较好的完成载体姿态测量的任务。     

RF MEMS器件时变结构电磁特性数值计算方法

准确掌握射频微机电(RF MEMS)器件的电磁特性是WSN节点射频收发前端设计可靠与否的关键,为解决RF MEMS器件时变结构的电磁特性数值计算问题,建立了RF MEMS器件垂直运动结构的机电耦合模型,实现了模型的时域离散,在时域有限差分的基础上,提出电(磁)介质参数插值的新思路,详细阐述了线性电(磁)介质参数插值法的基本思想,并推导了一维线性插值的计算公式.仿真实验结果表明,该计算方法具有易实现、速度快、效率高的特点.     

QMEMS晶振的MEMS器件真空度测量方法研究

QMEMS晶振是一种采用MEMS(micro-electro-mechanical system)加工技术充分发挥石英(Quartz)晶体材质特性制造出的高性能、高集成度的新型石英晶振。利用QMEMS晶振体积小、性能稳定的特点,提出将QMEMS晶振作为传感器内置于MEMS器件管壳内部,对MEMS器件腔体内部真空度进行实时监测的方法。在对石英晶振测量真空原理进行分析的基础上,研究了QMEMS晶振的结构和管壳开口方法,设计了一套基于QMEMS晶振气压传感器的真空度测量系统,实现了对真空度的测量,并对系统进行了标定。试验表明,该真空计可实现1~30kPa压强范围的测量,测量精度约为5%,能满足MEMS器件实时真空度测量要求。     

基于MEMS的微小型自主直升机姿态测量系统

本文介绍了一个基于MEMS器件的微小型直升机姿态测量系统的设计与实现.该系统以实现微小型直升机的自主飞行为目标,采用了多种MEMS器件,整个系统体积小,重量轻,便于微小型直升机搭载.文章还重点讨论了利用多种传感器进行误差校正与数据融合,从而获得满足控制系统需要的姿态参数的方法.     

基于IMU旋转的MEMS器件误差调制技术研究

MEMS惯性器件低信噪比和漂移大成为影响其应用范围的主要因素,提出基于惯性测量单元(IMU)转动的MEMS器件误差旋转自补偿方法。将MEMS输出信息利用小波降噪技术进行预处理,以此消除旋转调制方案不能自补偿的随机噪声信号并提高器件输出信噪比,分析IMU转动方案下的误差调制原理并探讨旋转调制的工程可实现性。搭建MEMS转动实验环境并开展降噪与IMU静止和转动条件下的导航实验,结果表明,采用旋转状态下的MEMS惯导系统可有效地提高系统自身测姿和定位精度。     

小型电磁继电器动态特性测试系统

提出了一种光机电相结合,采用 Ｃ Ｃ Ｄ 电荷耦合器件测量电磁继电器动态特性的方法,阐述了其基本工作原理,分析了测试系统硬件及实验结果。     

DC/DC变换器精确频响特性分析与测量

采用一种非平均模型法对DC/DC变换器的精确频响特性如输入阻抗、输入输出电压传递函数等进行了分析.由于电力电子变换器同时具有连续和离散时间系统特性,平均模型法和离散模型法均不能对其进行精确的动态特性分析.提出将DC/DC变换器的切换开关等效成一个时变电路,从而将整个系统看成一个线性时变系统,使系统同时具备精确性和易于分析性.在此基础上,对DC/DC变换器的频响特性进行了解析求解分析和实验测量.实验证明,该方法克服了平均模型法和离散模型法的频率范围限制,在开关频率附近及开关频率之上均能精确反映DC/DC变换器的动态特性.     

Applications of SOI-based optical MEMS

After microelectromechanical systems (MEMS) devices have been well established, components of higher complexity are now developed. Particularly, the combination with optical components has been very successful and have led to optical MEMS. The technology of choice for us is the silicon-on-insulator (SOI) technology, which has also been successfully used by other groups. The applications presented here give an overview over what is possible with this technology. In particular, we demonstrate four completely different devices: (a) a 2 × 2 optical cross connector (OXC)with an insertion loss of about 0.4 dB at a switching time of 500 μs and its extension to a 4 × 4 OXC, (b) a variable optical attenuators (VOA), which has an attenuation range of more than 50 dB (c) a Fourier transform spectrometer (FTS) with a spectral resolution of 6 nm in the visible, and (d) an accelerometer with optical readout that achieves a linear dynamic range of 40 dB over ±6 g. Except for the FTS, all the applications utilized optical fibers, which are held and self-aligned within the MEMS component by U-grooves and small leaf springs. All devices show high reliability and a very low power consumption     

Devices,structures, and processes for optical MEMS

New processes and devices in the area of optical microelectromechanical systems (MEMS) as researched in the Berkeley Sensor & Actuator Center (BASC) are described. A technique and fabrication procedure is presented to produce high‐quality microlenses at selected locations in a micro‐optical system. Polarization beam splitters are produced by another process, and their performance is measured and described. A new, much simplified process to fabricate vertically offset comb actuating structures is applied in the design of high‐performance scanners, which are in turn used to control a laser ablation system. Very favorable performance comparisons are demonstrated between the researched system and a conventional commercial laser ablation system. A second system demonstration is a prototype Shack–Hartmann (SH) sensor, in which microlenses are mounted in carriages that can be individually addressed using the selectivity of their mechanically resonant mountings. This design is shown to increase markedly the dynamic range in wave aberration to which the SH sensor can be applied. A final application of optical MEMS design is to a reduced‐size, enhanced‐performance, phase shifting interferometer. Copyright © 2007 Institute of Electrical Engineers of Japan© 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

MEMS for Optical Functionality

We discuss key features of MEMS technology which enable new functionalities of microphotonic devices, that can by summarized as “arrayability”, i.e. the ability to make massively parallel optical devices in a small form factor, “reconfigurability,” the ability to change optical properties spatially and temporaly, and “nano positioning,” the ability to position micro-scale devices with nanometer accuracy. We present an overview of cases where a combination of these features has led to commercial successes by creating new optical functionalities, and discuss materials-related challenges and future trends for optical MEMS research and commercialization.     

MEMS optical scanners for microscopes

Microelectromechanical systems (MEMS) optical scanners have been around for more than two decades. Various applications have been presented, but few of them have advanced to the commercial level to date due to the difficulties of combination of optics and MEMS devices. This paper presents our activities of investigating MEMS scanner applications related to microscopic imaging. First, we started with developing a millimeter-sized one-dimensional scanner for commercially available laser scanning microscope. This microscope with the MEMS scanner is now commercially available. In order to take advantage of the miniaturization capability of MEMS, the next step was to miniaturize the whole optics together with the scanners. Miniaturized confocal microscope with a two-dimensional (2-D) scanner has been developed, and its feasibility and key issues are clarified. Additionally, an alternative 2-D scanner capable of scanning wide angle has been prototyped and fundamental characterization showed a promising result. Throughout the study, feasibility of MEMS optical scanners for microscopes has been demonstrated.     

Optomechanical model of surface micromachined tunableoptoelectronic devices

Linewidth is a critical performance parameter for many optoelectronic devices. We have developed a combined optical and mechanical simulation tool and demonstrate its application to micromachined vertical-cavity tunable optoelectronic devices. The deformation of the mirror surface is calculated from the area moment method. The optical field distribution is calculated by the Fox-Li method, and the diffraction losses are estimated from second-order perturbation theory. By comparison to experimental results, we find that the deformation of the central plate is well predicted by our theory. While deformation can be a major source of linewidth broadening in MEMS tunable optoelectronic devices, it is not the primary source in our devices     

Opportunities and challenges for MEMS in lightwave communications

Over the remarkably short interval of just a few years, optical microelectromechanical systems (MEMS) have breached the gulf from laboratory curiosity to advanced development and early trial deployment in lightwave-communications systems. This owes largely to the ease with which the technology has demonstrated high optical quality and reasonably fast tuning and switching subsystems that are compact and potentially low in cost. Lightwave micromachines now threaten to make possible functional structures for building tunable lasers and filters, dynamic gain-equalizers, chromatic dispersion-compensators, wavelength-add-drop multiplexers, and polarization-controllers that represent substantial improvements over the conventional state of the art. More extravagant yet, both in promise and in expectations, is the potential of MEMS as a means of building the large-port-count optical switches that are just now becoming needed by emerging mesh-based core transport networks. In this paper, we review the current status and prospects for MEMS in lightwave communications, with particular emphasis on high-port-count core optical cross connects, and discuss challenges that still confront this technology     

基于微电子机械系统的光学电流传感器原理与设计

光学电流传感器解决了传统电流互感器的缺点，但仍然存在生产困难、性能易受环境温度影响等不足，MEMS作为一种新兴技术，可批量生产各种性能良好的微电子器件，该文提出了将MEMS技术用于检测高压交流电的光学电流传感器。高压侧的传感装置由Rogowski线圈、MEMS扭转微镜和双光纤准直器组成。文中介绍了器件的高压侧敏感原理和光学检出原理，给出了器件的结构参数条件、模态分析和温度补偿结果，并利用ANSYS与Matlab软件对器件的性能进行了仿真模拟和分析。理论结果表明：温度补偿后，温度变化±50K时测试误差为0.2%，400A、2000A电流下的灵敏度分别为0.001dB/A 与0.09dB/A, 说明了基于MEMS技术的光学电流传感器具有一定的研究价值。