MEMS降阶宏模型仿真平台研究

随着MEMS系统级设计成为研究的热点,MEMS系统级CAD的开发日益重要.论文介绍了一种基于降阶宏模型MEMS系统级仿真平台,通过有限元方法提取MEMS器件几何物理数据.建立MEMS器件有限元模型.利用Krylov子空间算法缩聚自由度建立宏模型,通过系统级仿真平台对此进行系统级仿真. 整个流程通过VC++编译器调用ANSYS、嵌入封装的算法动态链接库、集成SIMULINK系统仿真器完成.并用双端固支梁实例对所有模块加以验证,仿真结果准确,计算效率较高.     

具有空间连续行为的微型压力传感器系统级建模

大多数MEMS器件(如梁、膜等)的动态特性方程为偏微分方程,因此建立对应组件的可重用参数化行为模型是一个难题.本文通过有限差分法把偏微分方程转化为常微分方程组,然后采用混合信号硬件描述语言进行描述,解决了该问题.针对电容式微型压力传感器,专门考虑膜片的空间连续行为以及结构、静电力的耦合作用,建立了包含接口电路在内的系统模型,据此进行了动态行为仿真.通过结果对比,验证了方法的实用性.相对于通用的参数化组件模型,当前MEMS商业化软件多采用逐个器件进行宏模型抽取的方式实现系统级建模和仿真.     

MEMS器件的计算机辅助设计方法和仿真研究

MEMS技术的进一步发展依赖于MEMS器件计算机辅助设计的发展和水平的提高。系统级仿真和多能量场耦合是MEMS器件计算机辅助设计的核心环节。提出了一种MEMS器件设计的参考方法,并对系统级仿真这一难点做了深入阐述。     

一种可支持任意流程的MEMS设计工具

当前MEMS CAD软件中可以支持的设计流程比较固定和单一,已不能完全满足由MEMS器件种类日益增多所带来的设计新需求.论文提出了一种可支持任意流程的MEMS设计方法,并基于此建立了设计工具原型系统.该方法采用通用的系统级、器件级和工艺级的三级架构,但以网表、标准格式的实体模型和版图文件分别作为这三个级别设计数据的出入口.设计了相应的信息提取算法及程序,实现了任意两个级别之间的数据自动传递,从而可以支持在该架构下的全部六种设计流程.尤其是由系统级到器件三维实体再到工艺版图的设计流程为国际上率先实现,其从功能逐步综合到器件结构,可有效减少设计的迭代次数.设计实例表明,基于该工具可以针对不同的MEMS器件选择最优的设计路线,显著提高了MEMS的设计效率.     

基于IP库的MEMS设计系统

针对MEMS设计系统中机械性能仿真不足、设计与加工脱节、缺少工艺验证等问题,借鉴了IC设计可重用思想,引入了具有知识产权的功能模块--IP的概念,提出了基于IP库的MEMS设计方法.该方法是Top-Down和Bottom-Up设计相结合的方法,其核心是MEMS IP库,关键技术包括IP库、虚拟工艺、虚拟运行等,分别对应IP管理、工艺级仿真系统以及器件行为级仿真系统.最后以电容式微加速度计设计为例,对双梁、四梁、疏齿等6种不同的结构分别进行了设计仿真、流水加工,封装和测试的过程,完成了器件从设计到成品的整个流程,验证了本文提出的设计方法和设计系统的有效性和正确性.     

面向三维实体建模的MEMS设计方法

根据"所见即所得"的设计理念,提出了一种面向三维实体建模的MEMS设计方法,实现了从三维实体到系统级模型或工艺版图的设计流程,使设计者可以首先直接建立器件的三维实体模型,在完成有限元分析后,可以通过组件映射和宏模型提取的方式获得系统级模型,再通过自动版图转换得到相应的工艺版图.此设计方法可以提高设计效率,并且保证了模型...     

基于Modelica的MEMS系统级多领域建模与仿真

分析了现有的MEMS系统级建模与仿真方法,讨论了运用Modelica语言进行面向对象的非因果关系建模方法,建立了基于Modelica的电容式微型静电致动器系统级模型,仿真结果证明了Modelica用于MEMS系统级多领域仿真的可行性.     

MEMS惯性组件的误差特性分析与标定

针对惯性器件输出受工作环境及器件自身噪声影响,导致惯性组件输出信噪比低进而影响系统定位测姿精度等问题,提出MEMS惯性组件误差分析与标定方案。利用Allan方差对MEMS输出进行辨识,对输出信息曲线拟合并确立MEMS器件误差项的误差取值,建立MEMS几何误差模型并设计分立式标定方案。转台实验结果表明,24位置及速率标定方法可实现惯性组件常值误差系数的有效分离与求取,对比器件误差补偿前后的结果,验证了误差修正方案的可行性。     

基于电渗流的微流控混和芯片系统级建模技术研究

微流控混合芯片是微流控芯片系统中的重要组成部分,其混合效率直接影响后续反应产物的分布和反应体系的容量.文中对基于电渗流驱动的微流控混合芯片的系统级建模技术进行了研究,本研究首先结合基于电渗流驱动的微流控混合芯片的控制方程,对系统各组件的参数化行为模型进行了提取,在此基础上编程实现了系统各组件的多端口组件模型,构建了基于电渗流的微流控混和芯片系统级模型,模型仿真结果与有限元方法相比,相对误差为2.5%,而仿真速度却远远高于有限元方法.表明该方法在不显著损失系统精度的前提下,可以更加有效的对系统性能做出评价.     

基于微机械加速度计的振速水听器的设计与分析

对基于惯性传感器的同振球型振速水听器的工作原理进行了说明.采用多端口组件网络方法建立了用于振速水听器的梳齿式硅微机械加速度计的系统级模型.对内置加速度计,外部采用弹性连接的振速水听器在平面声波作用下的响应进行了仿真分析.分析结果表明,振速水听器不失真测量的工作带宽取决于其与水介质的密度比、波尺寸、与弹性连接构成振动系统以及加速度计自身振动系统的特性参数.多端口组件网络方法能够有效地实现振速水听器的建模与仿真.     

分立活塞式MEMS微变形镜的系统级设计

利用实验室自主研发的集成设计平台,搭建了分立活塞式MEMS微变形镜的系统级行为模型,并对其有效性和准确性进行了验证;在此基础上完成了微变形镜的结构设计,并由仿真得到了结构的性能参数.研究结果表明,采用系统级方法进行MEMS器件的设计能够在确保求解精度的前提下,显著提高设计效率,缩短设计周期,减小设计成本;所设计的MEMS微变形镜的各项性能指标完全能满足一般自适应光学系统的应用要求.     

基于受力分析的MEMS薄膜系统级模拟方法的研究

介绍一种MEMS系统级模拟方法.该方法直接分析运动物体的受力情况,并结合能量原理,利用受控源的反馈实现耦合作用,建立机电耦合MEMS薄膜的等效电路模型.利用该等效电路实现对薄膜动态行为的系统级模拟,并将Spice和有限元法,Saber的模拟结果进行对比,验证了该模拟方法应用于二维情况分析的有效性.     

Reduced-order modeling of weakly nonlinear MEMS devices with Taylor-series expansion and Arnoldi approach

In this paper, we present a new technique by combining the Taylor series expansion with the Arnoldi method to automatically develop reduced-order models for coupled energy domain nonlinear microelectromechanical devices. An electrostatically actuated fixed-fixed beam structure with squeeze-film damping effect is examined to illustrate the model-order reduction method. Simulation results show that the reduced-order nonlinear models can accurately capture the device dynamic behavior over a much larger range of device deformation than the conventional linearized model. Compared with the fully meshed finite-difference method, the model reduction method provides accurate models using orders of magnitude less computation. The reduced MEMS device models are represented by a small number of differential and algebraic equations and thus can be conveniently inserted into a circuit simulator for fast and efficient system-level simulation.     

Free-Form Simulation of Sequential Etching and Surface Characterization for 3-D MEMS Fabrication

A new diffusion-based simulation model of isotropic wet etching and free-form surface characterization method for 3-D free-form microelectromechanical systems (MEMS) fabrication is presented in this paper. To simulate the etching process, a diffusion-based model solved by the finite-element method (FEM) has been developed, allowing extraction of more accurate etch-front data at discrete time steps. In the developed method, free-form MEMS objects are modeled as B-spline functions with material concentration. Finite elements are generated by discretization in the parametric domain of the free-form object and mapping back to the Euclidean space. Points on the etch front are extracted using a Z-map method. The extracted point data are characterized to obtain a B-spline representation of the etch-front surface. Examples from the isotropic etching simulation of 2-D and 3-D objects with both regular and free-form geometry are presented. The developed method allows the simulation of 3-D objects with free-form input and free-form mask opening and facilitates the simulation of sequential etching of free-form objects with irregular mask openings. This paper also discusses applications of the developed method in MEMS process planning that can be realized by taking advantage of the better control of geometry that it provides in MEMS fabrication.     

梳齿谐振器宏模型的系统级应用

宏模型的获取是由Krylov子空间投影法结合器件级有限元分析的宏建模方法来实现,利用此模型和基于可重用IP设计思想的系统级组件建模方法建立由VHDL-AMS语言描述的梳齿谐振器系统级模型,在华大VDE仿真平台上搭建出了梳齿谐振器的系统模型,并进行一系列的仿真,包括时域阶跃、交流电压信号仿真和频域交流小信号仿真,仿真结果与商用仿真工具ANSYS仿真结果保持良好的一致.     

Structured synthesis of MEMS using evolutionary approaches

In this paper, we discuss the hierarchy that is involved in a typical MEMS design and how evolutionary approaches can be used to automate the hierarchical synthesis process for MEMS. The paper first introduces the flow of a structured MEMS design process and emphasizes that system-level lumped-parameter model synthesis is the first step of the MEMS synthesis process. At the system level, an approach combining bond graphs and genetic programming can lead to satisfactory design candidates as system-level models that meet the predefined behavioral specifications for designers to trade off. Then at the physical layout synthesis level, the selection of geometric parameters for component devices and other design variables is formulated as a constrained optimization problem and addressed using a constrained genetic algorithm approach. A multiple-resonator microsystem design is used to illustrate the integrated design automation idea using these evolutionary approaches.     

Computer-aided generation of nonlinear reduced-order dynamicmacromodels. I. Non-stress-stiffened case

Reduced-order dynamic macromodels are an effective way to capture device behavior for rapid circuit and system simulation. In this paper, we report the successful implementation of a methodology for automatically generating reduced-order nonlinear dynamic macromodels from three-dimensional (3-D) physical simulations for the conservative-energy-domain behavior of electrostatically actuated microelectromechanical systems (MEMS) devices. These models are created with a syntax that is directly usable in circuit- and system-level simulators for complete MEMS system design. This method has been applied to several examples of electrostatically actuated microstructures: a suspended clamped beam, with and without residual stress, using both symmetric and asymmetric positions of the actuation electrode, and an elastically supported plate with an eccentric electrode and unequal springs, producing tilting when actuated. When compared to 3-D simulations, this method proves to be accurate for non-stress-stiffened motions, displacements for which the gradient of the strain energy due to bending is much larger than the corresponding gradient of the strain energy due to stretching of the neutral surface. In typical MEMS structures, this corresponds to displacements less than the element thickness, At larger displacements, the method must be modified to account for stress stiffening, which is the subject of part two of this paper     

MEMS stochastic model order reduction method based on polynomial chaos expansion

Modeling and simulation of MEMS devices is a very complex task which involve the electrical, mechanical, fluidic and thermal domains, and there are still some uncertainties need to be accounted because of uncertain material and/or geometric parameters factors. According to these problems, we put forward to stochastic model order reduction method under random input conditions to facilitate fast time and frequency domain analyses, the method firstly process model order reduction by Structure Preserving Reduced-order Interconnect Macro Modeling method, then makes use of polynomial chaos expansions in terms of the random input and output variables for the matrices of a finite element model of the system; at last we give the expected values and standard deviations computing method to MEMS stochastic model. The simulation results verify the method is effective in large scale MEMS design process.     

MEMS陀螺仪静态漂移模型与滤波方法研究

针对移动机器人上安装的MEMS陀螺仪进行研究,根据MEMS陀螺仪的实测数据,分析了其噪声特性,采用时间序列分析方法建立MEMS陀螺仪漂移的AR模型,进而通过Kalman滤波降低随机噪声对MEMS陀螺仪精度的影响。仿真结果表明:静态漂移的建模和滤波方法对提高MEMS陀螺仪精度是有效的。