压电力传感器中晶轴偏转产生的维间耦合研究

针对压电式石英力传感器的维间耦合现象,从敏感材料测量原理出发开展研究。结合优化算法,以控制维间耦合为目标,建立了石英晶轴偏转与传感器维间耦合的公式关系,计算了石英晶轴偏转角度的容差范围,并通过有限元仿真验证了公式精度。结果表明,晶轴偏转对传感器维间耦合影响较大,建立的公式在一定范围内可较高精度地计算维间耦合输出,为高精度压电传感器的研究提供了参考。

标定偏心下压电力传感器测试精度研究

面向大型薄壁构件自寻位加工检测一体化测控原理,研发了一种小型化多维压电力传感器并进行标定研究。分析静态标定时,偏载对压电传感器多维力测试精度的影响。通过对静态标定加载有偏差时传感器受力的理论推导得到,加载偏差使传感器的转换系数改变,导致向间干扰补偿系数失真,影响了横向干扰输出,降低了测试精度;分析了偏载程度对传感器测试精度的影响,提出了衡量加载点偏差程度的判别方法,发现微小加载偏心带来的附加干扰会超出传感器自身向间干扰指标规定的5%;针对机械连接偏载不可避免事实,找到了克服偏载对转换系数影响的输出比例归一化法,将向间干扰降到5%内。

压电力传感器晶片与电极接触刚度影响研究

以压电力传感器为核心的多分量测量系统是航空、航天等领域重要的力学测量装置。压电力传感器中晶片与电极结合面接触刚度是基础性能参数,对压电力传感器的分载效应及灵敏度,多分量测量系统的整体刚度及静、动态性能有直接影响。由于尚无对该参数的研究,导致在设计封装压电力传感器过程中缺少相应的理论依据,在使用多分量测量系统时存在标定困难等问题。针对以上问题,研究晶片与电极结合面接触刚度的影响因素,建立基于分形理论的接触刚度模型,优化了晶面表面形貌、压电材料、电极材料、预紧力等参数。在此基础上,研究接触刚度对传感器性能——刚度、灵敏度、固有频率等影响,提出一种以接触刚度为约束的晶片表面形貌优化方法。基于结构函数法,建立分形理论与实际工程测量参数的联系,通过两种压电晶体——石英与硅酸镓镧,四种电极材料——钛合金、不锈钢、黄铜、铝,试验验证了理论模型。试验表明,优化晶片表面分形参数、提高预紧力、选用弹性模量小的电极有助于提高晶片与电极接触刚度,进而提高传感器的整体刚度、灵敏度和固有频率。研究为高性能压电力传感器的设计提供了理论参考。

压电力传感器在木材切削中的应用

本文将两只单向压电力传感器,装在自行设计的弹性元件上,用来测量切削力F_x和法向力F_y,精确度为0.1N。

基于压电力传感器冲击功的检测方法研究

液动冲击回转钻探具有防止岩心堵卡、提高勘探效率的重要作用,冲击器冲击功的无损精确检测一直是困扰冲击器研究机构及生产单位的难题。本文利用压电力传感器、电荷放大器将冲击器的冲击力波形转换为电压波形信号,再利用 MP4221 采集板和基于 Visual C++语言研发的实时采集、显示软件将冲击力波形采集到 PC 机,并实时显示冲击力波形曲线;依据动量定理和冲量定理,通过研究冲击器冲击功与最大冲击力的关系,确定了冲击功与最大冲击力的关系式,即冲击功与最大冲击力的平方成正比。文章通过标定实验台架进行了可行性验证,实验表明,利用压电力传感器可以准确地检测出冲击力波形,结合标定台标定出的“冲击功-冲击力”关系式系数可以准确地计算出对应的冲击功波形。

平板式压电六维力传感器静态性能研究

针对弹性体式六维力传感器存在的瓶颈矛盾,提出一种非弹性体式平板式压电六维力传感器。目前研究这类六维力传感器的静态性能主要是试验标定法和数字仿真法,这两种方法无法找到传感器结构参数与传感器性能之间的数学关系,也就无法全面实现基于静态特性的结构参数设计。从研究这类传感器的灵敏度特性出发,分析传感器的测量原理,推导传感器的等效结构模型;提出基于灵敏度特性的静态数学解析模型,建立这类传感器的数值模型;结合传感器的数学解析模型和数值模型研制传感器试验原型并开展静态标定试验,测试灵敏度、各向同性度、维间耦合、线性度、重复性等静态特性参数。试验结果证明:平板式压电六维力传感器工作原理正确,解析数学模型和数字模型有效,研究结论为全面设计和研究这类多维力传感器的静态特性奠定了基础。

三向压电晶体力传感器的研究

三向压电力传感器是三向动态测力系统最基本的传感元件,它可以对空间任一个或多个力同时进行测量,分解并合成到三个座标轴上输出。若用几个三向力传感器按不同情况组成测力系统,可以对更复杂的力系进行综合动态测量。本文简要介绍了三向压电力传感器的原理及其结构形式,在此基础上设计了三向压电力传感器,并从刚度的观点指出了传感器设计的关键。在传感器制造过程中,对其制造工艺进行了探索。实践证明:所采用的工艺路线是合理的,所研制的三向压电力传感器的性能指标达到国际同类产品的水平。

换向器滚压加工过程监测系统

根据换向器滚压加工成形的要求,提出选用电涡流传感方法对换向器成形的接触间隙进行检测,同时利用压电测力方法主动检测成形过程力的变化,将两种信息融和,构成检测系统。研究了位移传感器输出与被测间隙宽度、深度等之间的规律、电压限幅问题以及试件边缘翘曲的影响。通过压电测力仪同步测量加工过程力的变化规律,分析了夹具轴状况、压轮位置、接触间隙对力信号的影响,并进行了实验验证,弥补了单一信号的不足,提高了检测系统的准确性和可靠性。

压电测力仪的动特性分析

用动力学的理论对压电测力仪的动态性能进行分析,建立测力仪的数学模型,导出压电测力仪的幅值误差与带宽,并与应变式测力仪进行了比较,说明电压测力仪动态测量精度高的原因,指出压电测力仪本身就部分地具有加速度补偿的功能。

虚拟仪器技术在甘蔗动态切割力测试中的应用

甘蔗切割过程中,动态切割力是反映切割过程的一个重要参数。本文研究了虚拟仪器技术在甘蔗动态切割力测试中的应用,组建了基于LabWindows/CVI技术的虚拟测试系统,利用压电力传感器测量切割力的动态过程。测试系统的最高采样率可达到200kSa/s,能很好的对瞬时的动态切割力进行测量。

A Novel Capacitive Pressure Sensor

A novel capacitive pressure sensor is presented, whose sensing structure is a solid-state capacitor consisting of three square membranes with Al/SiO2/n-type silicon. It was fabricated using pn junction self-stop etching combined with adhesive bonding,and only three masks were used during the process. Sensors with side lengths of 1000,1200,and 1400μm were fabricated,showing sensitivity of 1.8,2.3, and 3.6fF/hPa over the range of 410～ 1010hPa, respectively. The sensi- tivity of the sensor with a side length of 1500μm is 4. 6fF/hPa,the nonlinearity is 6. 4% ,and the max hysteresis is 3.6%. The results show that permittivity change plays an important part in the capacitance change.

Transparent Electronic Skin Device Based on Microstructured Silver Nanowire Electrode

Transparent, flexible electronic skin holds a wide range of applications in robotics, humanmachine interfaces, artificial intelligence, prosthetics, and health monitoring. Silver nanowire are mechanically flexible and robust, which exhibit great potential in transparent and electricconducting thin film. Herein, we report on a silver-nanowire spray-coating and electrodemicrostructure replicating strategy to construct a transparent, flexible, and sensitive electronic skin device. The electronic skin device shows highly sensitive piezo-capacitance response to pressure. It is found that micropatterning the surface of dielectric layer polyurethane elastomer by replicating from microstructures of natural-existing surfaces such as lotus leaf, silk, and frosted glass can greatly enhance the piezo-capacitance performance of the device. The microstructured pressure sensors based on silver nanowire exhibit good transparency, excellent flexibility, wide pressure detection range （0-150 kPa）, and high sensitivity （1.28 kPa-1）.

Failure Prediction Modeling of Lithium Ion Battery toward Distributed Parameter Estimation

Lithium ion battery has typical character of distributed parameter system, and can be described precisely by partial differential equations and multi-physics theory because lithium ion battery is a complicated electrochemical energy storage system. A novel failure prediction modeling method of lithium ion battery based on distributed parameter estimation and single particle model is proposed in this work. Lithium ion concentration in the anode of lithium ion battery is an unmeasurable distributed variable. Failure prediction system can estimate lithium ion concentration online, track the failure residual which is the difference between the estimated value and the ideal value. The precaution signal will be triggered when the failure residual is beyond the predefined failure precaution threshold, and the failure countdown prediction module will be activated. The remaining time of the severe failure threshold can be estimated by the failure countdown prediction module according to the changing rate of the failure residual. A simulation example verifies that lithium ion concentration in the anode of lithium ion battery can be estimated exactly and effectively by the failure prediction model. The precaution signal can be triggered reliably, and the remaining time of the severe failure can be forecasted accurately by the failure countdown prediction module.

Modeling of sensor function for piezoelectric bender elements

An analytical sandwich beam model for piezoelectric bender elements is derived based on the first-order shear deformation theory (FSDT), which assumes a single rotation angle for the whole cross-section and a quadratic distribution for coupled electric potential in piezoelectric layers. Shear coefficient is introduced to correct the effect of transverse shear strain on shear force and the electric displacement integration. Static and free vibration analyses of simply-supported bender elements are carried out for the sensor function. The results illustrate the high accuracy of the present model compared with the exact 2D solutions.

New Optical Fiber Pressure Sensor with Reflection Capsule

The ratio measurement by means of the sensing optical fiber and the reference fiber with different beginning positions, and the technique to improve the stability of the sensor are first described. Then the ability to restrain and compensate the interference of the same nature through the double channel ratio measurement is illustrated. Finally, the performance of sensor and its engineering design are discussed.

MEMS biomedical implants

The field of micro-electro-mechanical systems(MEMS) has advanced tremendously for the last 20 years.Most commercially noticeably,the field has successfully advanced from pressure sensors to micro physical sensors,such as accelerometers and gyros,for handheld electronics application.In parallel,MEMS has also advanced into micro total analysis system(TAS) and/or lab-on-a-chip applications.This article would discuss a relatively new but promising future direction towards MEMS biomedical implants.Specifically,Parylene C has been explored to be used as a good MEMS implant material and will be discussed in detail.Demonstrated implant devices,such as retinal and spinal cord implants,are presented in this article.

Integrated outburst detector sensor-model tests

Outbursts of methane and rocks are, similarly to rock bursts, the biggest hazards in deep mines and are equally difficult to predict. The violent process of the outburst itself, along with the scale and range of hazards following the rapid discharge of gas and rocks, requires solutions which would enable quick and unambiguous detection of the hazard, immediate power supply cut-off and evacuation of personnel from potentially hazardous areas. For this purpose, an integrated outburst detector was developed. Assumed functions of the sensor which was equipped with three measuring and detection elements： a chamber for constant measurement of methane concentration, pressure sensor and microphone. Tests of the sensor model were carried out to estimate the parameters which characterize the dynamic properties of the sensor. Given the impossibility of carrying out the full scale experimental outburst, the sensor was tested during the methane and coal dust explosions in the testing gallery at KD Barbara. The obtained results proved that the applied solutions have been appropriate.

Stabilization of Intensity- based Optical Fiber Pressure Sensor

A practical optical fiber differential pressure sensor is presented at first. Then the techniques of light source feedback, set up of reference channel, proportional measurement and other methods to improve the stability of the system as well as to reduce the interference with same nature are emphatically discussed. Finally, the experiment results of the developed instrument are given.

Sensor Hall Effect on Analyses Mechanical Stress

Measuring the magnetic field is a common practice in industrial processes. We can cite the voltage measurements through PTs （potential transformers）. This is a classic example of inductive field measuring, predicting to be measured quantity is of oscillatory nature, with the circuit instrumentation scaled and calibrated for a typical frequency of 50/60 Hz. For a long time, only the binary information： ＂this field＂ and ＂missing field＂ is needed. For example, only with this information can we identify the frequency of the rotating shaft. Currently, new technologies employ magnetic sensors for measuring positions （distances, angles, etc.） from the intensity of the magnetic field. Inductive sensors are inefficient on measurements of static fields, such as magnets, opening spaces for new linear Hall effect sensors, and static which deal with these situations without difficulty. The present study examines the behavior of the Hall sensor, making the measurement of the intensity of the static magnetic field of the rotating magnet and the same, verifying the effect of the speed at which the magnet passes the sensor in some way alter the measurement. The results are favorable manda and the versatility of these sensors in many different applications.

Flexible and transparent capacitive pressure sensor with patterned microstructured composite rubber dielectric for wearable touch keyboard application

The development of pressure sensors with highly sensitivity, fast response and facile fabrication technique is desirable for wearable electronics. Here, we successfully fabricated a flexible transparent capacitive pressure sensor based on patterned microstructured silver nanowires(AgNWs)/polydimethylsiloxane(PDMS) composite dielectrics. Compared with the pure PDMS dielectric layer with planar structures, the patterned microstructured sensor exhibits a higher sensitivity(0.831 kPa^-1, <0.5 kPa), a lower detection limit,good stability and durability. The enhanced sensing mechanism about the conductive filler content and the patterned microstructures has also been discussed. A 5×5 sensor array was then fabricated to be used as flexible and transparent wearable touch keyboards systems. The fabricated pressure sensor has great potential in the future electronic skin area.