MOEMS translatory actuator characterisation,position encoding and closed-loop control

Recent developments in optical micro-electro-mechanical systems (MEMS) have produced rapidly oscillating translatory micro-mirrors with out-of-plane mirror displacements exceeding ±100 μm, which have a great potential for various applications requiring high-speed optical path difference modulation. A key factor affecting their practical applicability is a reliable operation control of the MEMS element. Presented here is a pro-active solution combining a laser reference interferometer with a novel position detection scheme and a dedicated control circuitry. By demodulating and processing the laser reference signal, the zero-crossing point of the moving MEMS device can be detected with an accuracy of one interference fringe only. This allows generating a highly accurate mirror control signal in real-time, enabling the implementation of a unique closed-loop control of such MEMS devices and thus ensuring optimally stable MEMS operation and maximal mechanical amplitudes even under varying environmental conditions. The presented solution so provides a vital step forward in the real-world deployment of optical systems using translatory micro-devices.     

Design, modeling and first experimentation of a two-degree-of-freedom spherical actuator

This paper deals with the design of a two-actuated-degree-of-freedom (DOF) spherical electrical actuator for mobile robotic applications. It presents the different steps involved in this design, namely the choice of the actuation principle (induction), its application to the case of a spherical geometry and two DOFs, the analytical and numerical modeling of the motor, and the sizing and the manufacture of a first one-actuated-DOF spherical prototype. The first experimental results, obtained thanks to our test bench and presenting the torque vs rotor angular speed characteristic of the actuator, are likewise compared with the model predictions.     

Design, modeling, fabrication, and performances of bridge-type high-performance electroactive polymer micromachined actuators

Bridge-type high- performance polymer micromachined actuators (PMATs) based on an electroactive polymer, modified poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] copolymer had been designed, modeled, fabricated, and characterized. The results show that the material enables the PMAT to exhibit a high stroke level (60 /spl mu/m displacement with 1 mm lateral dimension microactuator) with high-load capability and high-displacement voltage ratio (DVR) over a broad frequency range (>100 kHz). The stroke reduction in fluid (Silicone oil) is less than 5% comparing with the displacement in air. Impedance analysis and displacement measurement indicate that the PMAT has strong resonance behavior and the resonance frequency can be tuned by varying the dc bias field. Furthermore, the resonance peak, as expected by theoretical study, shifted to 6.5 times lower in fluid than in air with the mechanical Q value reduction less than 40%. In addition, the performance of the PMAT was modeled based on the elastic and electromechanical properties of the materials utilized in the PMAT and the configuration of the device. The comparison between the model and the experimental result shows a good agreement and validates the model as an effective method for the future development of PMAT for various applications. The high frequency response and respected performance in fluid medium demonstrate that the PMAT has potential for high performance MEMS components in the applications of microfluid systems, air dynamic control, under water transducers, and mass sensors, etc.     

Micromachined III-V multimorph actuators for MOEMS applications - concept, design, and model

A multimorph configuration of III-V materials that is based on the global optimization method using the simulated annealing (SA) algorithm is proposed to enhance small intrinsic piezoelectric effect of such materials. In this paper, a novel piezoelectric multimorph microactuator design such as a five-layer multimorph is proposed and analyzed using both numerical and analytical methods for potential microoptoelectromechanical systems (MOEMS) applications. Previously published analytical multimorph models for MEMS, which have been shown to reduce to equivalent expressions, are also presented and used for design optimization. By imposing a set of "real-world" constraints on the designs, optimal device geometries, which are more realistic and visible, have been determined using the SA method. Design tradeoffs are also discussed in terms of potential utility for the multimorph actuator in MOEMS applications. Finally, the proposed multimorph models are verified by finite element simulations results.     

Design of wide range MEMS tunable capacitor for RF applications

The RF applications like voltage controlled oscillators, tunable filters, resonators etc., requires tunable capacitors in their designs. This paper presents the design of wide range MEMS tunable capacitors for RF applications. This design consists of an air suspended bottom plate and a fixed top plate. The top fixed plate and the suspended bottom plate form the tunable capacitor. The capacitance range of this tunable capacitor is from 69.172 to 138.344?nF. This range is wider compared with the conventional MEMS tunable capacitors of tuning ranges in pico Farads. The fabrication process is similar to that of the existing standard integrated circuit fabrication processes, which makes this design suitable for integrated RF applications.     

A high-stroke, high-pressure electrostatic actuator for valve applications

This paper presents a novel large-stroke electrostatic valve actuator for high-pressure applications. The combination of pressure balancing and flexible electrode structures ensures large flow gaps at a low actuation voltage. A simulation tool was built to evaluate the design parameters. Design specific, as well as general optimisations are performed. The model shows a 5.6 times (theoretical) performance improvement compared to earlier designs. A micromachined test structure was fabricated and evaluated. Measurement results are presented and discussed.     

Design and modeling of electromagnetic actuator in mems-based valveless impedance pump

This study models and optimizes the electromagnetic actuator in an MEMS-based valveless impedance pump. The actuator comprises an electroplated permanent magnet mounted on a flexible PDMS diaphragm and electroplated Cu coils located on a glass substrate. In optimizing the design of the actuator, the objective is to maximize the output flow rate of the micropump while maintaining the mechanical integrity of its constituent parts. The study commences by developing optimized theoretical models for each of the components within the actuator, namely the diaphragm, the magnet, and the micro-coils. The theoretical models are then verified numerically using FEA software. The magnitude of the magnetic force acting on the flexible diaphragm is calculated using Ansoft/Maxwell3D FEA software. The simulation results obtained by ANSYS FEA software for the diaphragm deflection are found to be in good agreement with the theoretical predictions. In general, the results show that the desired diaphragm deflection of 15 μm can be obtained by passing a current of 0.6–0.7 A through the micro-coil to produce a compression force of 11 μN. The valveless micro impedance pump proposed in this study is easily fabricated and is readily integrated with existing biomedical chips due to its plane structure. The results of this study provide a valuable contribution to the ongoing development of Lab-on-a Chip systems.     

微加速度计粘附问题的研究及应用

粘附是影响微机电系统(MEMS)可靠性的重要因素之一。针对MEMS的典型产品——微加速度计的粘附问题进行了研究,给出了2种典型的微加速度计的表征粘附特性的剥离数的表达式,并分析了将粘附条件应用于微加速度计的多学科设计优化之中,分析了其对系统结构设计产生的影响。     

Design,test, integration and packaging of MEMS/MOEMS, 2005

Microsystem Technologies -     

面向PaaS的Web系统动态性能建模工具的设计实现

按需供给是PaaS平台面临的一个核心挑战.传统以局部优化为目标的反馈控制方法难以实现全局资源供给最优,为了更合理分配资源,利用性能模型预测Web系统的资源需求就变得至关重要.随着平台服务化的发展,其部署方式由封闭环境转为开放的服务形式,为模型的构造提出了新的挑战:由于应用和平台分属不同组织,大大增加了解系统全貌的难度,所以传统手工建模方法除了建模难度大之外,更难以在开放的环境下实施;在开放和动态的环境下,用户的使用难以预期,而用户行为的改变又会极大的影响系统行为,因而也有必要使模型适应用户行为的变化.针对上述问题,给出了一种动态性能建模工具的设计与实现.该工具在Web系统中插入必要的探针收集系统运行时状态,并输出为日志.通过周期性的对这些日志进行分析,从大量数据中提取出性能模型,使其与实际用户使用情况相符.文中以TPC-W基准测试为例,验证了该系统的有效性.     

Design,closed-form modeling and analysis of SU-8 based electrothermal microgripper for biomedical applications

Microsystem Technologies - This paper presents design analysis of an SU-8 based 2-DoF electrothermal microgripper by developing a closed-form analytical model. The analytical model considers both...     

Design, fabrication, and testing of micromachined silicone rubbermembrane valves

Technologies for fabricating silicone rubber membranes and integrating them with other processes on silicon wafers have been developed. Silicone rubber has been found to have exceptional mechanical properties including low modulus, high elongation, and good sealing. Thermopneumatically actuated, normally open, silicone rubber membrane valves with optimized components have been designed, fabricated, and tested. Suspended silicon nitride membrane heaters have been developed for low-power thermopneumatic actuation. Composite silicone rubber on Parylene valve membranes have been shown to have low permeability and modulus. Also, novel valve seats were designed to improve sealing in the presence of particles. The valves have been extensively characterized with respect to power consumption versus flow rate and transient response. Low power consumption, high flow rate, and high pressure have been demonstrated. For example, less than 40 mW is required to switch a 1-slpm nitrogen flow at 33 psi. Water requires dose to 100 mW due to the cooling effect of the liquid     

On the mechanical behavior of a wide tunable capacitive MEMS resonator for low frequency energy harvesting applications

Microsystem Technologies - We present a method for tuning the resonance frequency of a comb resonator using a combination of mechanically softening and hardening springs in order to achieve a high...     

组件式机械仿真流程建模平台的设计与实现

在具体分析WFMC规范基础上,结合组件开发思想,采用Java语言,利用EMF和GEF技术,根据仿真流程实际需要抽象成仿真组件,实现了组件式机械仿真流程建模平台,并简要介绍了流程在执行期间的状态表示机制.根据抽象出的13个静力学仿真组件,利用此建模平台完成了针对机械产品静力学仿真流程模型的建立,并从语法上对流程进行了有效性检验,证明了平台的适用性和灵活性.     

Design of membrane actuator based on ferromagnetic shape memory alloy composite for synthetic jet applications

The active flow control (AFC) technology has been studied and shown that it can help aircraft improve aerodynamic performance and jet noise reduction. AFC can be achieved by a synthetic jet actuator injecting high momentum air into the airflow at the appropriate locations on aircraft wings. To produce strong synthetic jet flow at high frequency, a new membrane actuator based on ferromagnetic shape memory alloy (FSMA) composite and hybrid mechanism was designed and constructed. The hybrid mechanism is the stress-induced martensitic phase transformation caused by large force due to large magnetic field gradient, thus enhancing the displacement, as the stiffness of shape memory alloy reduces due to the martensitic transformation. This sequential event can take place within milliseconds. The high momentum airflow will be produced by the oscillation of the circular FSMA composite diaphragm close to its resonance frequency driven by electromagnets. Due to large force and martensitic transformation on the FSMA composite diaphragm, the membrane actuator that we designed can produce 190 m/s synthetic jets at 220 Hz.     

Design and development of a piezoresistive pressure sensor on micromachined silicon for high-temperature applications and of a signal-conditioning electronic circuit

The deposition of diamond films on silicon substrate by MWPECVD is described and microstructural characteristics of the obtained films are reported. The resistive and piezoresistive properties of the diamond-on-silicon films have been measured beyond 200 °C by means of a purposely developed apparatus, and experimental results are reported. The piezoresistive properties at high temperature are exploited in the development of a micromachined pressure sensor capable of operating at up to 350–380 °C. A dedicated signal-conditioning electronic circuit is being designed and its functioning principle is here described.This work was funded by the Italian National Research Council under the project MADESS.This paper was presented at the Conference of Micro System Technologies 2001 in March 2001.