微机械加速度传感器性能的等效电学模拟

建立了微机械电容式加速度传感器的等效电学模型,通过振动特性的等效电路模型分析了加速度传感器对正弦加速度信号,阶跃加速度信号,及存在反馈时的直流加速度信号的振动位移响应情况;利用压控电容模型分析了加速度传感器检测正弦加速度信号时的小电容检测电路的性能。模拟结果表明采用反馈可以拓宽加速度传感器的测量范围,利用等效电学模型可以优化接口电路的整体性能。     

一种微机械陀螺自激驱动方式的电学模拟

为提高微机械陀螺的检测精度，稳定驱动振动速度幅度，提出了微机械陀螺的自激驱动方式，它能够使驱动振动自动稳定在驱动模态的固有频率上振动，以及保持恒定的驱动振动速度幅度。根据自激驱动电路原理，建立了驱动动力学方程的等效电路模型，用PSPICE软件对电路的工作状况进行了模拟，模拟结果验证了该方法切实可行。     

基于子结构模型的音叉振动式微机械陀螺的检测电容解析方法

为建立加工缺陷对微机械陀螺性能影响的机理性模型,解决高精度微机械结构优化设计的计算时间问题,以微机械加工技术制备的音叉振动式微机械陀螺为研究对象,利用多自由度动态有限元解析理论,提出基于子结构模型的检测电容解析法,实现微陀螺实际工作状态的模拟,并对模拟结果进行试验验证。从实例解析出发,发现微陀螺加工缺陷和工艺误差虽然对其结构固频特性影响不大,但是对其最终输出的电容检测特性具有较大影响这一重要现象。解析方法和结果在提高微机械陀螺解析精度和解析效率的基础上,对多物理场耦合工作环境下音叉振动式微机械陀螺健壮性能的解析和评价具有重要的参考价值。     

PMNT热释电紫外电定标探测器的仿真模拟

首先分析了热释电探测器工作原理,然后利用PSPICE的ABM（analog behavioral modeling）功能对PMNT（钛酸铅一铌镁酸铅）热释电紫外电定标探测器进行仿真模拟,建立其等效电路模型。该模型可以模拟PMNT热释电紫外电定标探测器热学和电学特性的瞬态响应和频率响应。将等效电路模型与放大电路相接,可以模拟热释电探测器系统,分析不同条件下探测器的响应特性,从而可以提高热释电探测器系统的性能,进而为紫外电定标奠定基础。     

行波超声电机的运转特性及其电学建模研究

首先建立了压电层合梁的压电振动方程,并引入六端等效电路对振动进行描述。再根据电机定子与压电梁的结构对应关系,推导出定子的导纳频响方程,并给出理想定子的等效电路;针对定子在其工作频区的导纳特性,构建出定子的二端等效电路;在对耗损、预压力、负载、温度等因素建模基础上,构建出电机完整的等效电学模型。最后,通过电机扫频试验验证了所建立模型的有效性。     

超声电机定子振动分析的模态选择方法

在超声电机定子振动模态有限元分析的基础上,对结构模态截断,仅保留特定的模态,实现了模型降阶。用APDL实现了从有限元分析结果中自动提取特定的模态参数和相应等效电路模型的电学参数。仿真计算了定子的机械和电学响应,与实验数据对比表明,减缩的低阶运动模型保持了原系统的主要特性。     

电容式环形微机电振动陀螺的设计

针对环形振动陀螺结构对称、模态特性参数相同与抗干扰特性好的特点,提出了一种新型的电容式环形微机电振动陀螺。设计了S形弹性支撑梁形式的硅基环形振动陀螺敏感结构,并仿真分析了陀螺的工作模态与幅频响应特性。根据环形振动陀螺的动力学特性,研究了陀螺的机电接口形式与硅基电极的设置方法,建立了硅基电极的电学参数模型与陀螺的角速度敏感模型。基于深离子刻蚀技术设计了简单可行的传感器制备流程,并成功制备了陀螺的敏感结构。实验测试结果显示,该环形微机电振动陀螺驱动与检测模态的谐振频率分别为9 028.86Hz与9 036.15Hz,品质因数分别为25 051与25 026,标度因数为0.589 7mV/((°)·s~(-1))。实验结果验证了陀螺设计与研究方法的正确性,为高性能硅基微机电陀螺的研制提供了一种可行的方案。     

基于遗传算法的微机械陀螺的多学科设计优化

基于micro-electro-mechanical system(MEMS)技术的微机械陀螺是集传感器、致动器、检测与控制等于一体的复杂多学科交叉系统，其整体特性是各个子系统综合作用的结果。在充分考虑工艺、结构、电路、工作环境等多学科或因素的约束条件下，提出微机械陀螺的多学科概念设计模型。以陀螺的灵敏度最大为优化目标，利用遗传算法对设计模型进行全局优化，获得初步的最优设计方案，并采用有限元软件ANSYS验证优化结果的正确性。     

含间隙二自由度碰撞振动系统等效电路仿真

在机械系统中,由于机械构件之间广泛存在间隙,运动过程中会发生非线性弹性碰撞现象.以含间隙二自由度碰撞振动系统为研究对象,建立数学模型,在Matlab软件中进行数值仿真分析.在此基础上,在Muhisim软件中应用函数发生器、电阻、电容、运算放大器和示波器等模拟电子元件,建立等效的电路模型进行仿真分析.结果 表明:等效电路...     

一种栅型结构微机械陀螺的研究

介绍了一种新型结构微机械陀螺的设计及制作。新型陀螺的驱动振动和敏感检测振动的阻尼均为滑膜阻尼，且几乎相同，惯性质量块为栅型结构，由弹性悬臂梁支撑，驱动固定电极和敏感检测固定电极位于惯性质量块下方。分析了新型陀螺的工作特性，说明了陀螺结构参数对陀螺灵敏度的影响，实验结果表明，大气状态下，新型栅结构微机械陀螺的驱动和敏感检测品质因子Q均可达到66。     

An equivalent electrical circuit design for pipeline corrosion monitoring based on piezoelectric elements

Underground pipelines are important infrastructure for transporting energy resources, particularly water and oil. Due to the high risk of damage and possible consequences, close monitoring of pipelines is a serious challenge for researchers and decision makers. Piezoelectric sensors/actuators are being used to monitor the physical characteristics of pipelines, including corrosion and crack. Piezoelectric ceramics as transmitters and/or receivers are connected to data concentrators in order to monitor the defects in pipelines. The performance and accuracy of this system highly depends on the accurate interpretation of the received electrical signals due to changing mechanical fields. However, due to the existence of two different fields, namely, electrical and mechanical, in this problem, simulation and interpretation of the damages occurring in pipelines is a consistent challenge. This paper proposes an equivalent electrical circuit model for a complete monitoring system which contains piezoelectric ceramics and a pipeline equivalent electrical circuit with corrosion defects and cracks through the pipeline. The pipeline is integrated with PZT sensor and actuator, in which PZT actuator generates waves along the thickness of the pipeline and its response is received by a PZT sensor. The proposed model approximates the electrical signal achieved by the PZT sensor to a complete health monitoring system. As the sensing signals in the present model are in one single field (i.e. electrical instead of mechanical and electrical), analysis and signal processing are more efficient, and the results are better understood. Numerical examples and, where applicable, simple tests have been presented to show the functionality and performance of the system.     

Modeling and characterization of piezoelectric cantilever in fluids at different temperatures

This paper introduces measurement and modeling of a piezoelectric beam used as a sensor in different types of liquids. It is immersed in different fluids at temperatures increasing from 20 °C to 50 °C. The working principle is based on detecting different resonance frequencies of the cantilever in different solutions. The oscillation of piezoelectric beam is measured using a vector network analyzer. An electrical equivalent circuit derived from a resonator model is used to simulate the experimental data. These calculated circuit constants have been related to physical properties of liquids under test. The combination of these liquids which includes non-conducting and conducting solutions, exhibiting low and high viscosity covers a good range of common physical properties of fluids. Main focus of this research is to explore the capability of piezoelectric cantilever as a liquid sensor with the influence of temperature. The equivalent circuit model has been proved to be viable to fit experimental data in non-conducting solution but less effective in conducting solution.     

磁流体动力学陀螺仪的结构设计与实验研究

磁流体动力学陀螺仪不存在传统陀螺仪的机械磨损和光学陀螺仪寿命易受光学器件制约的缺点,因而具有高精度、宽频带、长寿命的特点,此外还具有抗冲击、体积小、重量轻等综合性能。该传感器不但在惯性导航中表现优异,同时在卫星微角振动测量及寻北等领域也具有广阔的应用前景。通过对磁流体动力学陀螺仪基本工作原理进行简要分析,对简化模型进行了推导,并提出一种磁流体动力学陀螺仪的结构设计方法;对磁路进行仿真,获得工作间隙处磁感应强度分布,并代入磁流体仿真环节;对流动进行仿真,同时对样机进行标定实验,可得出标定过程的仿真与实验间差值的平方和均值的开方为5.69 m V,非线性度为0.6%,表明通过研究导电流体的流动过程进而分析该陀螺仪的性能是十分必要的,并证明了磁流体动力学陀螺仪具有良好的发展前景。     

Validation of thermal and electrical model for induction motors using fiber Bragg gratings

This works presents the simulation and validation of the thermal, electrical and mechanical models of a three-phase induction motor (TIM). Fiber Bragg grating (FBG) sensors are used to measure stator temperature and validate the thermal model. The knowledge of the relationship between losses and temperature variation in the TIM makes a simulation of the motor possible. To determine losses in the TIM an equivalent electrical circuit in arbitrary reference frame is used, which combines a traditional model with the more usual modeling of losses in the stator iron. The thermal study of the motor is performed using an equivalent thermal circuit formed by thermal capacitances and thermal conductivities that are separately considered for the stator and rotor. The losses calculated with the electrical and mechanical models are the input parameters for the thermal model. The simulation of the electrical model produces an error of approximately 4.2% when determining the Joule effect losses in the motor when compared to the experimentally obtained results. The simulation of the mechanical model presents an error of 0.2% for the losses due to friction and ventilation. The stator and rotor temperature, obtained with the thermal model, presented a high correlation with the measured values. The thermal model presents a maximum error of 0.75 °C when one compares them to the average experimental values of temperature in the stator during the temperature transient behavior. When the temperature in the stator reaches steady state, the experimental and simulated results converge to the same values. The use of FBGs to measure temperature in the machine allowed a thermal model to be developed, which also uses the mechanical losses of the machine and is the main contribution of this work.     

圆筒形电容式粮食水分传感器的数学模型与影响因素分析

分析了粮食的介质特性,说明了圆筒形电容式粮食水分传感器的测量原理,得出了传感器电容参数与被测粮食含水量关系的数学模型.运用粮食的导电浴盆效应得出了传感器的等效电路,讨论了影响传感器电容量的因素,为圆筒形电容式粮食水分传感器的设计提供了理论依据.     

电容式油藏物理模拟饱和度测量传感器

设计了一种用于测量油藏物理模拟平均饱和度的电容式传感器,建立了传感器的数学模型,对电容式传感器测量饱和度的原理进行了详细分析,讨论了传感器的检测电路原理,完成了传感器的检测电路设计,在虚拟电子工作平台上,对该检测电路做了仿真实验分析,仿真数据表明该传感器具有较好的非线性。在油藏物理模拟实验的平面模型上进行了实验测试,验证了用该测量方法测量油藏物理模拟饱和度是可行的,传感器的电路设计是可靠的。     

一种新型电感式位移传感器

提出一种结构简单轻巧，驱动及测量电路简单,性能较好的新型电感式位移传感器，可用于机械直线位移及位置的测量，给出了传感器的结构和测量电路的原理图，对工作原理进行了分析，并讨论了温度补偿的方法，该传感器已应用于高档轿车的电子无级变速系统中，使用效果令人满意。