一种双环境力下的硅基MEMS执行器设计与分析

基于发射过程引信保险机构的工作原理,设计了一种应用于双环境力下的MEMS执行器,建立了执行器中可动部件的动力学模型,研究了影响执行器工作的因素.应用有限元法在ANSYS/LS-DYNA软件下对MEMS执行器进行动力学仿真分析,得到执行器可动部件的运动曲线和整体的应力云图.计算结果表明,该执行器在引信的后坐环境和离心环境下均能可靠执行动作,并且具有结构紧凑、质量轻的特点.     

三种环境力下MEMS保险机构的设计与分析

基于发射过程引信保险机构的工作原理,设计了一种应用于子母弹下的MEMS保险机构.在后坐力、离心力和抛撒力作用下,建立了相应的动力学模型,研究了影响保险机构工作的因素.应用ADAMS软件,对MEMS保险机构进行动力学仿真分析,得到相应的运动曲线.计算结果表明,该MEMS保险机构在后坐环境、离心环境和抛撒环境下能够可靠执行动作,并且在勤务处理时是安全可靠的.     

基于二阶Krylov子空间投影法建立MEMS宏模型

利用宏模型对MEMS系统进行系统级仿真是求解MEMS耦合问题的有效方法.对大规模系统方程通过矩阵子空间投影实现自由度缩聚来建立宏模型的方法得到了广泛应用.常用的Krylov子空间法只能对状态空间描述的一阶系统进行降阶处理.本文介绍了二阶Krylov子空间理论,运用Amoldi算法直接对大规模二阶系统进行自由度缩聚来生成宏模型.将此方法与有限元数值分析结合对电热驱动微夹钳进行了宏建模.对电热微夹钳宏模型的仿真结果表明此方法建立的宏模型可以准确反应系统的动态行为,满足精度要求,同时极大地降低了计算复杂度,提高了计算速度.     

发火控制电路中微执行器

本文针对引信发火控制电路中微执行器输出力矩弱的特点,利用微沟道和凝胶纤维把化学能转化成机械能形变技术,设计了一种新型MEMS微执行器.这种微执行器是通过静电力克服机械弹性力使极板产生相对运动,控制发火控制电路的导通;利用凝胶纤维的收缩力解除引信发火控制电路保险从而达到开启和关闭的目的.文中对所设计的结构进行ANSYS仿真,验证它的可行性并优化了结构参数.这种新型微执行器最大的特点是功耗小,输出功率大,具有很高的机械效率.     

MEMS陀螺随机误差辨识与降噪技术

针对MEMS陀螺精度受随机误差的影响,并随测姿积分算法逐渐增长的问题,采用时间序列分析法对MEMS陀螺的输入输出数据进行辨识,建立系统的ARMA模型,利用卡尔曼滤波方法对随机误差进行降噪处理,最后对随机误差降噪技术进行实验验证.实验结果表明,降噪后随机误差方差为降噪前的7.17%,由降噪后的MEMS陀螺数据计算得到的姿态角误差小于1°,能够满足低成本导航系统的需要.     

一种高精度MEMS梳齿驱动器有限元仿真方法及实验

为解决目前MEMS梳齿电容驱动器由于边缘效应导致的理想计算模型计算误差较大问题,利用有限单元法中的能量法,提出了一种对梳齿驱动器电容量进行精确仿真计算的方法并以实际制作的微机械陀螺质量块上的90对梳齿驱动器为对象,分别利用该方法及常用的CMATRIX仿真方法对其电容值进行了仿真计算。两种方法得到的电容量的计算结果分别为1.5283pF和1.5793pF。二者与利用高精度LCR测试仪得到的结果 1.5172pF的相对误差分别为0.73%和4.09%。实验结果表明,该方法对考虑边缘效应的MEMS梳齿电容驱动器具有较高的计算精度。     

基于光流技术MEMS平面微运动特性的测量

实现MEMS动态测试技术中平面微运动特性的测量，关键是记录MEMS运动过程中的瞬间运动状态，并恢复MEMS面内的运动历程．为此，介绍了光流技术，并提出利用邻域优化法进行微结构运动的光流计算．组建了基于频闪成像的MEMS平面运动测试系统，通过该系统获得MEMS谐振器周期运动不同相位下的清晰图像序列．利用邻域优化计算该图像序列的光流，选取合适的邻域大小和阈值，得到了MEMS谐振器在特定驱动频率下的运动幅度-相位图及其拟合曲线，从而获得微谐振器在此驱动频率下的运动幅度值为2．12μm．实验结果表明，该方法是准确有效的．     

基于ANSYS的静电微执行器吸合现象分析

本文基于静电场和弹性薄板理论,对MEMS静电结构的吸合现象进行了理论分析并给出公式化结果。然后借助于有限元分析软件ANSYS,对微开关中的静电驱动微悬臂梁进行分析,得到其吸合现象对应参数的标准数值,最后实现理论数值和标准数值的比较,以期对MEMS微执行器设计提供一定的理论支撑。     

基于压电陶瓷的引信物理电源的建模与设计

压电陶瓷能将弹药发射环境中的机械能转换为电能,压电电源就是基于此特性为引信供电的环境能源。提出一种压电发电建模方法,利用其对引信压电电源的发电特性进行了理论研究。共包括两个步骤:利用总能量求偏导法推导出并联压电叠堆产生的电压、电荷及电能公式;将压电结构发电模型等效为电路形式,利用电路知识分析得到压电电源的电能输出表达式。然后利用MATLAB软件进行了数值仿真分析,最后以所得理论模型为指导、以最大化提高发电量为目的进行压电电源的设计。     

基于MEMS传感器高精度流量控制手段的实现

市场上主流的MEMS流量传感器在其量程的小段范围内综合精度最高可达到0.5%F.S,大范围的测量误差2.5%F.S左右,甚至9%F.S以上。如果直接采用该传感器对流量进行控制,不仅造成较大的测试误差,而且占据较大的空间。文章采用某型号流量传感器作为测量元件,利用传感器最高精度的测试范围,实现了小量程传感器对大流量的高精确控制。对MEMS流量控制器的方案进行了详细介绍,以10 scm/min为例,对其进行了设计计算。结果表明,该方法满足设计要求,达到了设计目的,为气体流量的精确控制提供了一条简单可行的途径。     

DYNAMIC ANALYSIS OF MICRO-ELECTRO-MECHANICAL SYSTEMS

The subject of this paper is dynamic analysis of Micro-Electro-Mechanical Systems (MEMS). MEMS are integrated, movable microstructures with electronics, in the 0⋅1–1000 μm size range. Dynamic analysis of MEMS is complicated by the fact that there are two physical domains, electrical and mechanical, with non-linear coupling between them. Numerical simulation of the dynamics of MEMS is carried out by a hybrid BEM/FEM (Boundary Element and Finite Element Method) approach, FEM for the structure and BEM for electrostatic analysis. Several numerical techniques are proposed for time-integration in order to obtain the non-linear dynamic response. These techniques are tested on a ‘generic’ MEMS device, a microtweezer. The Modified Newmark Method is determined to be the best approach for simulation. Various interesting non-linear phenomena are observed from the numerical simulations. Some of these non-linearities have also been observed in previous experiments with MEMS. A simple physical analogue to the microtweezer is proposed. Study of this model helps one understand some of the complex non-linear responses of the microtweezer.     

残余应力对RF MEMS开关谐振频率偏移的影响

由沉积工艺产生的残余应力对RF MEMS开关的动态特性有重要影响。利用变量分离法推导出桥模式RF MEMS开关的频率方程组。给出二分法求解频率方程的流程图,并进行实例计算。计算结果表明,残余应力引起的频率偏移随着t/L的减小而增加;残余应力与频率偏移之间呈现出明显的非线性特性。     

一类静电驱动微结构谐振传感器的吸合不稳定性研究及控制

本文以一类静电驱动微结构谐振传感器为研究对象,基于安全域思想研究了系统直流偏置电压和交流激     

Integrated structure and control design of actively controlled structures using substructure decomposition

This paper presents a substructuring based approach to the combined structure and control system design problem for flexible space structures. The proposed approach involves decomposing the structure to be controlled into a number of substructures. The substructure information obtained through finite element analysis is synthesized to reconstruct a reduced order model for the entire structure. Two approaches for controller design based on linear quadratic regulator (LQR) theory are proposed. The first approach involves designing a controller for the entire structure obtained by assembling individual substructures. For the second approach, the global controller is obtained by assembling all subcontrollers designed at the substructure level. The integrated control/structure design problem is solved iteratively until a minimum weight design is achieved. A numerical example which compares the results obtained from both the methods with those obtained by directly synthesizing a global controller for the entire structure is presented. The results indicate that both methods proposed herein provide good agreement with the results obtained by analyzing the structure in its entirety.     

Ka波段DMTL移相器用RFMEMS电容式并联开关研制(英文)

本文设计并制作了一种用于Ka波段分布式MEMS传输线(DMTL)移相器的MEMS电容式并联开关.通过理论计算和工程经验,大致定义了开关的结构尺寸.采用HFSS软件建立了开关的三维电磁场模型并优化了关键结构参数.仿真表明:开关在Ka波段插入损耗小于0.15 dB,回波损耗大于15 dB.采用CoventorWare软件进行了开关的机电耦合仿真,得出其驱动电压为2.1 V.为了满足流片单位表面微加工工艺的约束,对开关的设计版图和微加工工艺进行了多轮改进,得到初步的MEMS电容式并联开关工艺样品.单个MEMS开关的动态特性测试结果表明:施加36 V驱动电压时,微桥下拉的高度约为2μm.测得的36 V驱动电压与初始设计的2.1 V有较大的差异,原因在于限于流片单位的工艺约束,临时修改了结构设计,主要变化是增加了微桥的高度以及微桥(即上电极)与下电极之间的初始间距.     

一种汽车主动悬架系统模糊控制器设计及试验

设计了一种在线可调整的模糊控制器，其模糊控制规则表可以用解析的方法进行计算。不仅体现了模糊控制算法对非线性系统具有的明显优势，而且利用LMS自适应模块调整模糊控制器的修正因子，改善单一模糊控制算法对专家先期经验的依赖缺陷。针对简化的汽车模型，在以单频信号作为激励源的仿真研究过程中，该算法对悬架系统的振动控制收到了较好的效果。在两自由度的悬架系统试验台架上进行了试验研究，结果进一步证明该算法的有效性。     

Small-signal perturbation technique used for DSP-based identification of a three-phase three-level boost-type Vienna rectifier

New small-signal-modelling technique and validation procedures are applied to a three-phase three-level boost-type AC/DC Vienna converter. The adopted methodology consists of three steps: the first one is to elaborate the converter steady state and dynamic models that are derived by means of a local linearisation around the nominal operating point from the state space-averaged model, initially expressed in abc physical variables and then transformed into dqo synchronous reference frame. Twenty transfer functions relating the inputs to the outputs of the system are therefore obtained. The second step is the numerical verification using the averaged state space model and the converter model built in SIMULINK/MATLAB. Finally, an experimental validation of the transfer functions is carried out using a 1.5 kW laboratory prototype on the basis of the DS 1104 real-time controller board of dSPACE. The results are quantified and compared as magnitude and phase Bode graphs. It is confirmed that the proposed new small-signal model represents rather accurately the real system and is therefore reliable for further tasks such as dynamic characteristic analysis, numerical simulation as well as controller design purposes     

Vibration Performance,Stability and Energy Transfer of Wind Turbine Tower via Pd Controller

In this paper, we studied the vibration performance, energy transfer and stability of the offshore wind turbine tower system under mixed excitations. The method of multiple scales is utilized to calculate the approximate solutions of wind turbine system. The proportional-derivative controller was applied for reducing the oscillations of the controlled system. Adding the controller to single degree of freedom system equation is responsible for energy transfers in offshore wind turbine tower system. The steady state solution of stability at worst resonance cases is studied and examined. The offshore wind turbine system behavior was studied numerically at its different parameters values. Furthermore, the response and numerical results were obtained and discussed. The stability is also analyzed using technique of phase plane and equations of frequency response. In addition, the numerical results and comparison between analytical and numerical solutions were obtained with MAPLE and MATLAB algorithms.     

Three‐dimensional modelling of intergranular fatigue failure of fine grain polycrystalline metallic MEMS devices

This paper presents a 3D finite element model to investigate intergranular fatigue damage of microelectromechanical systems (MEMS) devices and to account for the effects of topological randomness of material microstructure on fatigue lives. The topology of MEMS material grain structures is modelled using randomly generated 3D Voronoi tessellations. Continuum Damage Mechanics is used to model progressive material degradation due to fatigue. A new 3D micro‐grain debonding procedure is developed to consider both intergranular crack initiation and propagation stages. The fatigue damage model is then used to investigate the effects of microstructure randomness on the variability in fatigue life of cantilever MEMS devices. Three different types of randomness are considered: (1) topological disorder due to random shapes and sizes of the material grains, (2) variation in material properties considering a normally (Gaussian) distributed elastic modulus and (3) material defects or internal voids. The stress–life results obtained are in good agreement with experimental data. The progression of damage and the overall crack pattern obtained from the microcantilever beam model are consistent with empirical observations.     

虚拟MEMS加工工艺建模、实现与系统验证

利用虚拟现实技术对MEMS加工工艺进行仿真,并将其引入设计环节,最终可以解决MEMS生产中设计与加工脱节的问题。MEMS加工工艺的核心是工艺模型。首先,在深入分析单步MEMS加工工艺的基础上给出了规则描述的工艺模型,其次,利用专家系统技术实现了系统。进一步用一种全新的器件微流量泵的工艺设计和虚拟加工过程验证了系统的可扩充性。