共查询到20条相似文献,搜索用时 31 毫秒
1.
2.
3.
4.
5.
本文针对地铁车辆高速断路器测试的复杂性和可靠性的需求,设计了用于城市轨道交通中使用的高速断路器的试验台.通过该试验台,可以对高速断路器的固有吸合时间、固有释放时间、最低吸合电压、最高释放电压等性能参数进行测定. 相似文献
6.
7.
在常规机械中很少考虑的微小静电力会对MEMS的电路产生一定影响,同时MEMS的元件在静电力作用下会发生变形,进而使得MEMS的几何结构和电容等产生变化,加之目前MEMS试制成本较高,因此,必须对整个系统的静电性能和机电性能进行分析.利用边界元素法,对MEMS各元件进行静电性能分析;采用有限元分析软件包对MEMS作机电性能分析,探讨了驱动电压与位移的关系、位移变化与电容的关系等.通过仿真测试发现,可提高设计质量,降低成本,缩短研制周期. 相似文献
8.
《自动化仪表》2018,(12)
电活性聚合物(EAP)致动器是一类极具发展潜力的智能材料。通过对尺寸为10 mm×2 mm离子型聚吡咯致动器施加阶跃电压、方波、正弦波、斜波电压,研究分析致动器位移响应与驱动电压波形、幅值和频率的关系。阶跃电压下,致动器位移响应经过5s左右达到稳定状态,仅1 V驱动电压就可使致动器稳态弯曲位移变化值达2. 22 mm。在幅值为±1 V方波驱动电压下,致动器稳定状态位移变化值则为1. 96 mm。试验结果表明:驱动电压增加,迁进迁出致动聚合物层的离子增多引起聚合物层的氧化还原加剧,致动器位移响应滞后于驱动电压变化;其位移响应幅值随驱动电压增加而增大,呈线性关系。当驱动电压波形与幅值相同时,致动器位移变化幅值随驱电压频率的增高而减小,且呈非线性关系。该致动器机电响应特性试验为微阀、微型机器人、生物医学设备、人工肌肉、电化学传感器、贮能材料等领域的实际应用提供了理论参考。 相似文献
9.
为实现微小型机器人的精密运动定位,提出一种基于粘滑运动原理的足式微小型机器人.机器人足由双压电膜驱动,本身为空间不等截面的弹性梁结构.首先建立了柔性足的有限自由度模型和机器人系统的动力学模型.然后根据粘滑驱动中的粘滞和滑移过程的不同特点,分别对粘滞过程的静力学与滑移过程的瞬态动力学进行了分析,得到了机器人运动位移、分辨力与驱动电压之间的关系,并分析了粘滞-滑移过程中摩擦力的变化以及足尖的状态切换过程.分析结果表明,在粘滞阶段,基体的静态位移与驱动电压近似呈线性关系,且随驱动电压的增高而增大;在滑移阶段,由于柔性足的振动及振动与摩擦力的耦合关系,足端的滑移距离及基体位移与驱动电压之间存在非线性关系.建立了机器人样机,对机器人的运动分辨力和位移响应进行了测试,实验数据显示,基于粘滑运动原理,机器人可以实现0.88μm的高运动分辨力. 相似文献
10.
11.
Dynamic response of a torsional micromirror to electrostatic force and mechanical shock 总被引:1,自引:0,他引:1
In this paper dynamic characteristics of a capacitive torsional micromirror under electrostatic forces and mechanical shocks
have been investigated. A 2DOF model considering the torsion and bending stiffness of the micromirror structure has been presented.
A set of nonlinear equations have been derived and solved by Runge–Kutta method. The Static pull-in voltage has been calculated
by frequency analyzing method, and the dynamic pull-in voltage of the micromirror imposed to a step DC voltage has been derived
for different damping ratios. It has been shown that by increasing the damping ratio the dynamic pull-in voltage converges
to static one. The effects of linear and torsional shock forces on the mechanical behavior of the electrostatically deflected
and undeflected micromirror have been studied. The results have shown that the combined effect of a shock load and an electrostatic
actuation makes the instability threshold much lower than the threshold predicted, considering the effect of shock force or
electrostatic actuation alone. It has been shown that the torsional shock force has negligible influence on dynamic response
of the micromirror in comparison with the linear one. The results have been calculated for linear shocks with different durations,
amplitudes, and input times. 相似文献
12.
Rakesh Kalyanaraman Gino Rinaldi Muthukumaran Packirisamy Rama Bhat 《Microsystem Technologies》2013,19(1):61-70
Nonlinear dynamic investigation of electrostatically actuated micro-electro-mechanical-system (MEMS) microcantilever structures is presented. The nonlinear analysis aims to better quantify, than the linear model, the instability threshold associated with electrostatically actuated MEMS structures, where the pull-in voltage of the microcantilever is determined using a phase portrait analysis of the microsystem. The microcantilever is modeled as a lumped mass-spring system. The nonlinear electrostatic force is incorporated into the lumped microsystem through an equivalent area of the microcantilever for a given electrostatic potential. Electro-mechanical force balance plots are obtained for various electrostatic potentials from which the static equilibrium positions of the microcantilever are obtained and the respective conservative energy values are determined. Subsequently, phase portrait plots are obtained for the corresponding energy values from which the pull-in voltage is estimated for the microsystem. This pull-in voltage value is in good agreement with the previously published results for the same geometric and material parameters. The results obtained for linear electrostatic models are also presented for comparison. 相似文献
13.
This paper presents a generalized model for the pull-in phenomenon in electrostatic actuators with a single input, either charge or voltage. The pull-in phenomenon of a general electrostatic actuator with a single input is represented by an algebraic equation referred to as the pull-in equation. This equation directly yields the pull-in parameters, namely, the pull-in voltage or pull-in charge and the pull-in displacement. The model presented here permits the analysis of a wide range of cases, including nonlinear mechanical effects as well as various nonlinear, nonideal, and parasitic electrical effects. In some of the cases, an analytic solution is derived, which provides physical insight into how the pull-in parameters depend upon the design and properties of the actuator. The pull-in equation can also yield rapid numerical solutions, allowing interactive and optimal design. The model is then utilized to analyze analytically the case of a Duffing spring, previously analyzed numerically by Hung and Senturia, and captures the variations of the pull-in parameters in the continuum between a perfectly linear spring and a cubic spring. Several other case studies are described and analyzed using the pull-in equation, including parallel-plate and tilted-plate (torsion) actuators taking into account the fringing field capacitance, feedback and parasitic capacitance, trapped charges, an external force, and large displacements 相似文献
14.
Elata D. Bochobza-Degani O. Nemirovsky Y. 《Journal of microelectromechanical systems》2003,12(5):681-691
This work presents a systematic analysis of electrostatic actuators driven by multiple uncoupled voltage sources. The use of multiple uncoupled voltage sources has the potential of enriching the electromechanical response of electrostatically actuated deformable elements. This in turn may enable novel MEMS devices with improved and even new capabilities. It is therefore important to develop methods for analyzing this class of actuators. Pull-in is an inherent instability phenomenon that emanates from the nonlinear nature of the electromechanical coupling in electrostatic actuators. The character of pull-in in actuators with multiple uncoupled voltage sources is studied, and new insights regarding pull-in are presented. An analytical method for extracting the pull-in hyper-surface by directly solving the voltage-free K-N pull-in equations derived here, is proposed. Solving simple but interesting example problems illustrate these new insights. In addition, a novel /spl alpha/-lines numerical method for extracting the pull-in hyper-surface of general electrostatic actuators is presented and illustrated. This /spl alpha/-lines method is motivated by new features of pull-in, that are exhibited only in electrostatic actuators with multiple uncoupled voltage sources. This numerical method permits the analysis of electrostatic actuators that could not have been analyzed by using current methods. 相似文献
15.
The most striking characteristic of the voltage-to-deflection curve of an electrostatically actuated beam is pull-in. The actual value of the pull-in voltage depends on: drive mode, temperature dependence and dielectric charging related drift. These aspects have been analysed using structures designed for a 9 V nominal pull-in voltage and fabricated in a commercially available epipoly process. Single-sided clamped beams have been used to avoid any influence of residual stress in the beam on pull-in. Typical results are: less than 5% variation of the pull-in voltage over a wafer, 0.17–1.9 V hysteresis depending on drive mode, a −1 mV/K TC and −12 mV drift during the first 2 weeks of operation. 相似文献
16.
Yin Zhang Yisong Wang Zhihong Li Yubo Huang Dachao Li 《Journal of microelectromechanical systems》2007,16(3):684-693
The snap-through and pull-in instabilities of the micromachined arch-shaped beams under an electrostatic loading are studied both theoretically and experimentally. The pull-in instability that results in a system collision with an electrode substrate may lead to a system failure and, thus, limits the system maximum displacement. The beam/plate structure with a flat initial configuration under an electrostatic loading can only experience the pull-in instability. With the different arch configurations, the structure may experience either only the pull-in instability or the snap-through and pull-in instabilities together. As shown in our computation and experiment, those arch-shaped beams with the snap-through instability have the larger maximum displacement compared with the arch-shaped beams with only the pull-in stability and those with the flat initial configuration. The snap-through occurs by exerting a fixed load, and the structure experiences a discontinuous displacement jump without consuming power. Furthermore, after the snap-through jump, the structures are demonstrated to have the capacity to withstand further electrostatic loading without pull-in. Those properties of consuming no power and increasing the structure deflection range without pull-in is very useful in microelectromechanical systems design, which can offer better sensitivity and tuning range. 相似文献
17.
Pons-Nin J. Rodriguez A. Castaner L.M. 《Journal of microelectromechanical systems》2002,11(3):196-205
The absolute maximum value of the voltage developed across an electrostatic actuator when driven by a current source has been calculated as well as an absolute minimum for the pull-in time. These two results are calculated for a drive using a δ-pulse of current and numerical assessment is given to show that for a nonzero parasitic capacitance, a realistic shape of the current pulse, or a finite value of the damping coefficient do not increase the maximum value of the voltage developed beyond that limit and that the pull-in time is always larger than the analytical minimum. A scaled-up macromodel of an electrostatic actuator has been used to register voltage transients to validate the theoretical predictions 相似文献
18.
The nonlinear dynamics of the parallel-plate electrostatically driven microstructure have been investigated with the objective of finding a dynamic voltage drive suitable for full-gap operation. Nonlinear dynamic modeling with phase-portrait presentation of both position and velocity of a realistic microstructure demonstrate that instability is avoided by a timely and sufficient reduction of the drive voltage. The simulation results are confirmed by experiments on devices fabricated in an epi-poly process. A 5.5-V peak harmonic drive voltage with frequency higher than 300 Hz allows repetitive microstructure motion up to 70% of gap without position feedback. The results of the analysis have been applied to the design of a new concept for positioning beyond the static pull-in limitation that does include position feedback. The measured instantaneous actuator displacement is compared with the desired displacement setting and, unlike traditional feedback, the voltage applied to the actuator is changed according to the comparison result between two values. The "low" level is below the static pull-in voltage and opposes the motion, thus bringing the structure back into a stable regime, while the "high" level is larger than the static pull-in voltage and will push the structure beyond the static pull-in displacement. Operation is limited only by the position jitter due to the time delay introduced by the readout circuits. Measurements confirm flexible operation up to a mechanical stopper positioned at 2 /spl mu/m of the 2.25 /spl mu/m wide gap with a 30 nm ripple. 相似文献
19.
Jan Dittmer Lars Hecht Rolf Judaschke Stephanus Büttgenbach 《Microsystem Technologies》2010,16(8-9):1665-1671
We present an advanced RMS voltage sensor based on a variable parallel-plate capacitor using the principle of electrostatic force. The device is fabricated in a micromechanical surface process with a high-aspect ratio actuator, reinforced by copper electroplating employing a sacrificial photo-resist layer. Another copper layer with a coplanar waveguide below the actuator provides separated excitation and sensing electrodes. Flip-chip technology is employed for low-loss electrical connectivity. The presented design has a plate area of up to 3 × 3 mm2 and an initial gap distance of only 1.5 μm. We present results achieving a pull-in voltage below 1 V at frequencies from DC up to 1 GHz and sensitivities up to 1 fF/mV. 相似文献
20.
Nadal-Guardia R. Dehe A. Aigner R. Castaner L.M. 《Journal of microelectromechanical systems》2002,11(3):255-263
When a voltage source drives an electrostatic parallel plate actuator, the well-known pull-in instability limits the range of displacement to 1/3 of the gap. Different strategies have been reported to overcome this limitation. More recently, experimental results have been presented using a capacitor in series with the actuator. Nevertheless, this strategy requires higher voltage than the pull-in voltage value to achieve full range of travel. In order to reduce the operating voltage, a switched-capacitor configuration has been also proposed. In this paper, two different approaches are introduced to control charge in the actuator by means of current driving. Theoretical equations derived for each method show that full range of travel can be achieved without voltage penalty. Both approaches are based on the use of current pulses injecting the required amount of charge to fix the position of the movable plate. Experimental measurements, showing that displacement beyond the pull-in point can be achieved, are in good agreement with the theoretical and the predicted simulated behavior 相似文献