A Fully Integrated Ring-Type Fluxgate Sensor Based on a Localized Core Saturation Method

This paper reports a new micromachined fluxgate sensor with extremely low power consumption, based on a localized core saturation method. The extremely low power consumption is achieved by quick saturation at the localized core region associated with sensing coils 10 times smaller than the excitation coils. We designed and optimized the sensor by using the electromagnetic simulation software MagNet, and we compared the simulation results with the experimental results. The device exhibits a power consumption of ~14 mW, a sensitivity of 650 V/T at 60 muT, and a sensor span of ~200 muT. In comparison with previously reported micro fluxgate sensors, the newly developed sensor consumes 7 times less power, but at the expense of sensor span and linearity     

Low-Power Printed Circuit Board Fluxgate Sensor

A new printed circuit board flat fluxgate sensor with integrated coils and amorphous alloy core was developed and its excitation parameters optimized for low-power consumption. The power consumption achieved with 10 kHz, 300 mA p-p pulse excitation with duty cycle 12.5% was only 3.9 mW, which is three times lower than that for sinewave B excitation. The sensor sensitivity reached 94 V/T. The required excitation bridge supply voltage was only 0.47 V. The low-cost low-power sensor has a temperature offset stability of 120 nT in the -20 to +70 degC temperature range and 0.17%/degC open-loop sensitivity tempco due to the use of a new core embedding technique. The perming error due to 10 mT field shock was suppressed below 1.2 muT. The short-time offset stability was 38 nT within 3 h. Thus the developed sensor is more precise and less energy consuming than a periodically flipped anisotropic magnetoresistance (AMR) sensor. The achieved parameters are sufficient for compass with 0.1deg error     

液体饱和法岩心孔隙度测量不确定度评定

依据行业标准SY/T 5336-2006规定,采用液体饱和法对岩心孔隙度进行了测量。建立了数学模型,分析确定测量岩心孔隙度的不确定度来源,并对测量过程中的不确定度分量进行逐层分析与合成,得到合成标准不确定度为0.088%,扩展不确定度为0.18%。计算结果显示由样品测量重复性引入的不确定度分量对合成标准不确定度贡献较大,是不确定度的主要来源。由质量校准、样品称量引入的不确定度相对来说较小,可忽略不计。     

RF Energy Transmission for a Low-Power Wireless Impedance Sensor Node

The proper management of energy resources is essential for any wireless sensing system. With applications that span industrial, civil, and aerospace infrastructure, it is necessary for sensors and sensor nodes to be physically robust and power efficient. In many applications, a sensor network must operate in locations that are difficult to access, and often these systems have a desired operational lifespan which exceeds that of conventional battery technologies. In the present study, the use of microwave energy is examined as an alternate method for powering compact, deployable wireless sensor nodes. A prototype microstrip patch antenna has been designed to operate in the 2.4 GHz ISM band and is used to collect directed radio frequency (RF) energy to power a wireless impedance device that provides active sensing capabilities for structural health monitoring applications. The system has been demonstrated in the laboratory, and was deployed in field experiments on the Alamosa Canyon Bridge in New Mexico in August 2007. The transmitted power was limited to 1 W in field tests, and was able to charge the sensor node to 3.6 V in 27 s. This power level was sufficient to measure two piezoelectric sensors and transmit data back to a base station on the bridge.      

磁通门CMoS接口电路设计

为实现三端式磁通门接口电路的集成．提出一种新颖的包括驱动和检测功能的磁通门CMOS接口电路．驱动电路采用开关网络和负反馈环实现全差分驱动来替代传统的隔离变压器驱动．通过实时平衡驱动电极上的电压信号来抑制电源电压的漂移以及温度变化的影响．检测电路利用驱动信号二倍频为基准的开关相敏解调实现二次谐波提取,同时采用闭环检测．以提高系统线性度．该电路基于0．5IxmCMOS工艺实现．测试结果表明,该微型磁通门磁力计（三端式探头和CMOS接口电路）的灵敏度为30．8μV／nT,非线性度为0．62％,电源电压为10V,功耗为100mW,芯片面积仅为15．54mm2．     

新型摇摆质量微陀螺的设计与制作(英文)

首先介绍了两种结构完全对称的高灵敏度的摇摆质量陀螺.设计并制作了一种对角驱动的新型摇摆质量微陀螺.利用硅的各向异性湿法腐蚀等MEMS体加工技术,简化了该微陀螺的制作工艺.该微结构的对称性、一致性和加工精度有很大改善,尤其是振动梁、激励部件和敏感部件等关键部件.详细阐述了该微陀螺的工作原理和结构设计,完成了微陀螺关键部件的制作和样机组装.利用NF公司的FRA 5087频率响应分析仪测试了样机大气下的振动模态,其中驱动频率为5.563 2 kHz,检测频率为5.553 4 kHz,频差为9.8 Hz,小于0.2%.利用频谱分析的方法测试了样机的哥氏力.测试结果表明这种摇摆质量微陀螺的设计与制作方法是可行的.     

Motion Characterizations of Lateral Micromachined Sensor Based on Stroboscopic Measurements

In this paper, we illustrate the capabilities of the Planar Motion Analyzer (PMA) with a study of the dynamic behavior of a micromachined structure. Dynamic characterizations and measurement settings are also demonstrated. The optical measurement system uses the light-emitting diode (LED) based vibration measurement technique for imaging, and then measuring the lateral resonant frequency and sensor displacements, as well. The PMA analyzes in-plane vibrations of a MEMS device under a clear microscope. Its working principle is based on the stroboscopic principle. Based on this principle, characterization results in both time and frequency domains can be accurately generated and analyzed. Our device example for the measurement is a tunneling-based micro-resonator, which was fabricated using the Backside Released SOI process. The tunneling behavior of the sensor can be observed by controlling the motion of the tunneling tip towards the opposing electrode with a typical gap of 10 Aring. This very small gap can be easily achieved by the Bode measurement of PMA for shifting the LED-strobe flashes at a small increment of phase angle over the whole motion of the sensor. In other words, smaller motions of the tip will be easily achieved, when the number of shots per period are larger. For our tunneling measurement, the phase angle shift is 0.5deg with 720 shots per period. The lateral moving proof mass is suspended by the folded springs, and its tip protrudes to an opposing electrode by means of electrostatic forces. The tunneling current has been observed to be exponentially increasing, when the tunneling gap is decreasing. However, the further large current is actually a contacting current, when the mechanical contact happens between the tunneling tip and the opposing electrode. The resonant frequency of the device is ~5 kHz obtained from the Bode measurement     

方波激励的无铁芯多分段电感位移传感器

传统的差动变压器式电感位移传感器存在着铁芯惯量大、线性范围小、对正弦波激励电源的品质要求高、正弦波发生及传感信号提取电路复杂等问题。本文提出了一种具有多抽头螺管线圈和轻质滑环结构的电感位移传感器 ,取消了铁芯 ,采用方波激励 ,由简单的运放电路合成传感信号 ,并利用传感器自身提供的温度信号进行温度补偿 ,克服了传统差动变压器存在的问题。实验结果表明 ,这种传感器具有优良的综合性能     

Design and Analysis of a Tri-Axis Gyroscope Micromachined by Surface Fabrication

This paper presents an innovative microgyroscope design. Solely by planar fabrication and wet etching, the proposed microgyroscope is capable to detect three-axis angular rates. The induced motion of individual seismic mass modules are designed to respond in the directions orthogonal to each other in order to decouple the obtained measures. In our work, three pairs of high-resolution differential capacitors with signal processing circuits are employed to measure the angular velocity components in three axes. On the other hand, the drive electrode comb is used to constantly vibrate the outer-ring in tangential direction by sinusoidal voltage. The signal bandwidth about the principle axis is increased by distributed translational proof masses, placed 90$^circ$ apart orderly around a circle. Each individual translational proof mass is designed to move in radial direction so that superior mode matching (i.e., resonance mode) can be easily, to some extent, achieved. The planar suspension flexures are particularly designed in geometry to resist acceleration in drive mode but increase the stroke of tilting angular displacement of the outer-ring such that the resolution of detected angular rate for the corresponding sense mode is upgraded. By considering the complicated geometry of the suspension flexures, finite-element method (FEM) is employed to examine the potential maximum induced mechanical stress. The dynamic equations of the proposed gyroscope are established are well so that the embedded gyroscopic effects are unveiled. More importantly, the efficacy of the drive and sense circuits modules is verified by commercial softwares Hspice and Multisim. By intensive computer simulations and preliminary experimental studies, the resolution, bandwidth and sensitivity of the tri-axis gyroscope are expected to be fairly enhanced if a certain degree of tradeoff is preset.      

一种无线传感器网络被动定位方法设计与实现

从无线传感器网络节点自定位出发,分析比较了无线传感器自定位的几种常见定位算法,并给出现有算法存在的问题;在嵌入GPS模块的无线传感器网络汇聚节点上提出一种新的被动定位方法,并在软硬件上得到了实现．与传统的定位方法比较,它避免了无线传感器网络必须在每个节点嵌入GPS模块的同时,能在不增加体积、成本、通信功耗的情况下提供精确的定位位置．     

Method for Measuring a Surface Profile Using a Mechatronic Profiler with Parallel Control of Sensor Drives

Measurement Techniques - Issues associated with improving the maneuverability and operating speed of a mechatronic profiler, as well as extending the profile measurement range for various surfaces,...     

Design and Simulation of a Nanophotonic Traceable Memory Using Localized Energy Dissipation and Hierarchy of Optical Near-Field Interactions

Optical near-field interactions allow energy localization at scales smaller than the diffraction limit of light. They also show intrinsic hierarchical responses, meaning that optical near-fields exhibit different physical behavior at different scales. In this paper, by combining the localized energy dissipation and hierarchy properties, we present an architecture for a novel traceable optical memory that records memory access events to each bit, which is useful in applications such as high-security information transfer. The basic principles are demonstrated by numerical simulations using a metal nanostructure.     

硅微陀螺仪闭环校正控制系统设计

为了提高硅微陀螺仪的精度,对硅微陀螺仪的闭环校正控制系统进行了研究.首先,推导了简化的开环系统传递函数,分析表明为了防止谐振峰值的出现,相对频差δf必须小于等于1/(2Qy).其次,利用反馈力矩器的负刚度效应,消除两模态的相对频差,提高系统的机械灵敏度.最后,在无频差情况下,设计一个带有无源阻抗网络的比例-积分-微分(proportion-integration-differentiation,PID)校正环节,校正后系统的相角裕度为52°,幅值裕度为18dB,闭环带宽为931 rad/s,实现了闭环系统校正.仿真和实验表明闭环校正电路是可行的.相对于开环检测,闭环校正系统的量程增加了1.6倍,标度因数非线性减小了45.6倍,零偏稳定性提高了2.56倍.同时,标度因数对称性、标度因数重复性、阈值和分辨率等性能都得到较大改善.     

微静电陀螺仪的结构设计与工艺实现

为了探索微机械陀螺突破精度极限的新途径,设计了一种基于环形转子、体硅加工工艺、转子5自由度悬浮的硅微静电陀螺仪.采用玻璃-硅-玻璃键合的三明治式微陀螺结构,提出了包括双边光刻、反应离子刻蚀(RIE)、电感耦合等离子体(ICP)刻蚀、玻-硅静电键合、硅片减薄、多层金属溅射等关键工艺的加工路线.在工艺设计中采用铝牺牲层对转子进行约束,在第2次玻-硅键合后再通过湿法去除牺牲层,以得到可自由活动的转子.基于提出的体硅工艺路线,成功加工出了微陀螺敏感结构,并完成了转子5自由度悬浮和加转实验,测试结果表明大气环境下转子转速可达73.3 r/min.     

咖啡壶的本土化造型设计

围绕咖啡壶造型设计,以本土化设计为指导,进行市场调研和设计,比较其优缺点,最终以古钟形状的咖啡壶为最终方案.整体上采用仿古设计,洋溢着传统文化,在细节的处理上,加入了现代设计元素,既有文化内涵,又不乏现代气息.     

CMOS像传感器光饱和效应研究

图像传感器在光学测量中具有重要作用,随着光源光强的提高,图像传感器处于饱和光强的情况越来越多.因此本文通过采用激光辐照CMOS像传感器的方法,研究了CMOS像传感器的饱和效应,明显观察到高光强使得图像灰度由亮变暗现象.该研究可以为高光强测试以及相机设计及后续图像处理提供参考.     

铂热电阻温度传感器非线性校正方法与电路设计

介绍铂电阻温度传感器非线性补偿的一种方法。给出铂电阻线性测温的设计原理和实际电路，运用数字原理对铂热电阻测温电路进行研究，为铂热电阻的非线性补偿方法提供理论依据。     

热固性硅树脂压注法制备多孔硅基陶瓷型芯研究

以石英玻璃粉为基体, 热固性硅树脂为增塑剂, 利用压注方法制备了多孔硅基陶瓷型芯, 研究了烧结温度和保温时间对样品性能的影响。研究结果表明: 随着烧结温度的升高, 反玻璃化进程加快, 在烧结温度1250℃, 随着保温时间的延长, 玻璃相发生了转变, 逐渐析出方石英, 且含量不断增加; 样品的线收缩率和失重随烧结温度的升高略微增加, 但烧结时间的影响较小。样品的失重主要是由于硅树脂的分解引起的。在1250℃烧结10 h后, 得到样品的收缩率为0.93%, 显气孔率为32.8%, 抗弯强度为9.08 MPa。