Robust resonant beams with a passively-controlled thermally-induced axial force and a designated stationary point

Microsystem Technologies - Chevron beams, also known as V-shaped beams, have been used and studied extensively as support structures and thermo-mechanical actuators. As a support, it can remarkably...     

管道气直驱执行机构在天然气长输管道工程的应用研究

在天然气输气管道工程中,紧急切断阀通常选用气液联动执行机构,但其结构复杂、价格昂贵;紧急放空阀常采用电动执行机构,但其在安全性方面存在不足。因此,有必要为安全仪表系统(SIS)阀寻找满足功能安全、结构简单并节省投资的其他类型执行机构。通过与气液联动执行机构、电液联动执行机构、气动执行机构及电动执行机构的性能和经济性比较,介绍了管道气直驱执行机构和其他类型执行机构的适用场合,并阐述了管道气直驱执行机构的概念、分类和应用情况。通过分析,得出了对于天然气管道工程中口径16英寸(1英寸=25.4 mm)或16英寸以下的紧急切断阀,管道气直驱执行机构更为适用的结论。这为以后的天然气长输管道工程中执行机构类型选择提供了参考和指导。     

压电式精密驱动器及其闭环控制系统设计

提出了一种以压电叠堆作为驱动源的新型步进直线精密驱动器,设计了直线驱动器的整体结构,分析了直线驱动器的工作原理。制作了直线驱动器样机并进行试验测试,试验结果表明:步距与电压间具有良好的线性关系,但驱动器存在步距误差。采用PCI—6229NI数据采集卡,使用LabVIEW软件设计了驱动器闭环反馈控制系统,对比试验结果表明:驱动器定位精度显著提高,可达到0.06μm。     

A novel microelectrostatic torsional actuator

Presently, the torsional actuator has gained a lot of attention in the area of microactuators. Because the torsional actuator cannot carry a substantial mechanical load in the out-of-plane direction, it is frequently used in some optical or electrical applications such as light modulators and spatial scanner devices. However, the performance of the torsional actuator is limited to the fabrication process and operating conditions. For instance, it is difficult to fabricate a torsional actuator with both a large rotating angle and large size moving plate. A novel electrostatically driven torsional actuator is proposed in this paper. The torsional actuator is fabricated through the integration of surface and bulk micromachining processes. Thus, the goal of fabricating a torsional actuator with a cavity right beneath the edge of the moving plate is reached. In addition, the thin film residual stress is exploited to modify the shape of the torsional actuator. The advantage of the proposed design is to increase the traveling distance of the actuator as well as to increase the area of the moving plate. In short, the proposed design provides the possibility of increasing the size of a moving plate without reducing its rotating angle. Therefore, the applications for the torsional actuator, such as image scanner and positioner, are increased.     

基于SMA的关节驱动器的力学分析及控制

分析了一种用于水下微小型仿生机器人的形状记忆合金(SMA)关节驱动器的力学特性,并通过模糊控制的方法对其进行了实验研究。结果表明:对于物理特性呈非线性、温度滞后、时变和受温度影响很大的SMA驱动器来说,采用模糊控制的方法,能够使驱动器稳定、平滑的工作,尽管产生了轻微的超调现象,但收到了令人较为满意的效果。因此,将模糊控制方法应用于SMA驱动器的控制有一定的理论意义和应用价值。     

基于MMST分组的一类MIMO非线性系统执行器故障自适应补偿控制

在多输入多输出(Multiple-input multiple-output,MIMO)非线性系统的执行器故障容错控制问题中,控制器能够处理的执行器故障集合的大小与执行器分组方法有很大关系.为扩大系统可处理的执行器故障集合,本文针对一类具有执行器故障的MIMO非线性最小相位系统,提出基于多模型切换(Multiple model switching and tuning,MMST)执行器分组的自适应补偿控制方法.考虑系统的执行器卡死、部分失效和完全失效故障,在微分几何反馈线性化的基础上,研究基于多模型切换的执行器分组切换指标和切换策略,设计了基于反演控制的自适应补偿跟踪控制律,所设计的控制律能保证系统在执行器故障时闭环稳定,渐近跟踪给定的参考信号,且提出的分组方法扩大了可补偿的执行器故障集合.仿真结果表明了本文设计方法的有效性.     

基于压电陶瓷微位移执行器的精密定位技术研究

阐述了压电陶瓷微位移执行器的驱动原理,介绍了执行器的性能与应用情况;利用自行设计的输出特性测试系统,对WTYD0808042压电陶瓷微位移执行器进行了相关实验研究,分析了执行器的非线性和迟滞特性;采用Duhem算子建立了压电执行器的迟滞模型,利用建立的Duhem模型作为PID反馈控制的前馈环节进行闭环精密定位控制的研究。实验结果表明:该模型能够有效降低非线性和迟滞特性对压电执行器位移输出精度的影响,提高执行器的动态响应特性。     

新型复合结构电热微驱动器的研制

在弯曲梁电热微驱动器原理的基础上,通过引入热膨胀系数更大的聚合物,提出了一种新型复合结构电热微驱动器。采用了ANSYS有限元分析软件,对其基本结构形式进行了系统的仿真分析,得到了一组初步优化的器件结构参数。仿真结果表明:新型电热微驱动器有更低的能耗和更大的位移。采用非硅表面微加工技术,成功制备了新型复合结构电热微驱动器。     

包含执行器动力学的子空间预测动态控制分配方法

针对具有冗余执行机构的过驱动系统的最优控制分配问题, 基于数据驱动的子空间辨识方法和预测控制理论, 提出了一种考虑执行器动力学特性的动态控制分配新方法. 在考虑范数有界不确定性的在线子空间辨识的基础上, 对执行器动力学特性进行不确定性建模, 再结合预测控制理论进行动态控制分配. 从而将执行机构的动力学建模、控制量最优分配和执行机构控制律的设计包含在一个子系统框架内, 对执行机构的模型不确定性具有更好的鲁棒性. 最后给出仿真实例验证了算法的有效性.     

Hybrid micro electrostatic actuator

A hybrid micro-electrostatic actuator is presented. The actuator integrates a vertical comb driving (VCD) unit and a parallel-plate driving (PPD) unit. The hybrid actuator is fabricated using a one structural layer microfabrication process, i.e., MetalMUMPs instead of a two-layer microfabrication process needed for traditional vertical comb-drive actuators by taking advantage of the residual stress gradient in the MetalMUMPs nickel layer, which raises the moving parts of the actuator above the substrate after release. The hybrid actuator significantly simplifies the fabrication process for vertical comb-drive actuators, i.e., turning a process requiring two structural layers into a process requiring only one structural layer and thus avoids any misalignment between the two layers. The hybrid actuator can generate larger force and then a larger displacement than the actuator having only the VCD with the same area since no extra space is needed for the PPD unit which uses the moving electrode existing in the VCD unit and a fixed electrode under the VCD unit. The VCD and PPD units in the hybrid actuator are subject to the same driving voltage and work together to pull the moving parts of the actuator downward. A model is established for the hybrid actuator to analyze its displacement. The analytical results show that displacement of the moving part of the hybrid actuator is about half of the gap between the electrodes of the PPD unit. Prototypes are fabricated and tested. With a driving voltage of 150 V, the hybrid actuator achieved a measured displacement of 6.48 µm.     

圆柱形介电弹性体驱动器的试验与分析

为了获得一种结构紧凑的介电弹性体驱动器,以VHB4910 为驱动材料,设计、实现了圆柱形驱动器． 通过对比试验得到的驱动器（有效长度为45mm）最大能够产生8.5mm 的位移,有效区伸长应变达到18.89%．采用 Yeoh 超弹性模型对驱动器进行有限元仿真,得到驱动器的输出位移为6.24mm．仿真与试验结果较吻合,文中分析 了仿真与试验结果之间产生差别的原因．圆柱形介电弹性体驱动器的研究可为该类驱动器的设计、分析与应用提供 指导．     

机电作动器悬架硬件在环仿真测试平台研究

为了提高汽车的平顺性,提出一种机电作动器悬架,设计了机电作动器悬架硬件在环仿真测试平台。建立基于机电作动器的主动悬架数学模型与仿真模型,以嵌入式系统单片机为主处理器设计机电作动器悬架的控制器;在此基础上,以dSPACE为模型运行载体搭建机电作动器悬架硬件在环仿真测试平台;利用该测试平台进行了仿真试验。结果表明所研究的硬件在环仿真测试平台具备较好的硬件在环仿真功能,能够对机电作动器悬架性能、主动悬架控制算法进行验证与评价。     

Enhancement of PZT embedded swing arm actuator using integrated read/write performance and actuation

The current technological challenges associated with the rotary-type seesaw arm actuator for small-form-factor (SFF) disk drives are the small skew focusing, which causes off-axis aberrations and reduces optical quality. This article develops a novel design for a seesaw arm actuator and suspension assembly that is based on a micro-PZT actuator to position pickup head. Dual-stage actuation relaxes the dynamic requirement on the focusing stroke. The proposed actuator with a tilt-compensation mechanism uses a PZT bender to drive pickup head focusing. This combined system, optical module and dual stage actuator, is effectively self-aligned the optical axis for read/write performance in both experiment and simulation result. Finite element modeling and dynamic measurements reveal significant improvements in the actuator bandwidth with and without micro-PZT actuator compensation.     

基于LS-SVM和SVM的气动执行器故障诊断方法

为了解决自确认气动执行器的故障诊断问题,提出了一种基于最小二乘支持向量机(LS-SVM)回归建模和支持向量多分类机(SVM)的执行器故障诊断方法,该方法利用LS-SVM回归建立气动执行器的正常模型,将实际输出与模型输出比较,产生残差作为气动执行器的非线性故障特征向量。利用聚类方法设计了层次支持向量多分类机结构,以残差作为输入建立支持向量多分类机,判断气动执行器故障类型。利用DABLib生成的故障数据对所研究方法进行了验证,并与基于PCA-SVM的故障诊断方法进行了比较,结果表明该方法有效的解决了气动执行器故障诊断的小样本和非线性问题。     

Novel H-beam electrothermal actuators with capability of generating bi-directional static displacement

A new H-beam electrothermal microactuator is proposed for providing bi-directional static displacement. The design concept and preliminary experimental results of H-beam actuators are presented in this paper. Due to its symmetric structural design, this H-beam actuator can avoid the influence from rotational torques during its bi-directional dynamic and static movement. The restoring force generated by cold beam of H-beam actuator potentially renders this new actuator capability of faster returning speed than conventional electrothermal actuator designs. H-beam actuator is able to generate 50 μm static stroke under 0.9 W electrical dc load. This H-beam electrothermal actuator is well functioned and exhibits good characteristics with high-level performance for industrial applications.     

软体仿蛙游动机器人关节式气动致动器研制

为实现仿蛙游动机器人的微小型化,增强其环境适应能力,结合软体材料的优势特点和青蛙划动推进的游动方式,提出了一种关节式气动软体致动器,该致动器在满足软体仿蛙机器人游动过程中的运动性能和力学性能的同时,使得其肢体结构更加紧凑、轻量．利用Yeoh本构模型和虚功原理,结合关节式气动软体致动器的几何参数,建立了致动器的形变分析模型．进而,在致动器总体尺寸受约束的情况下,以一定弯曲角度下致动器输出恢复力矩最大为目标,确定了致动器的具体结构参数．融合3D打印、模塑成型等加工工艺方法,加工制备了关节式气动软体致动器,并通过对比分析,确定了采用纤维线限制致动器径向凸起效应时纤维线的绕线形式和绕线密度．最后经过实验测试分析,该致动器质量约7.5 g,可实现由180°弯曲状态至伸直状态的形态变化,并且在弯曲角度一定时通过调整充入气压的大小可以匹配一定范围内不同大小的负载力矩,从而验证了针对软体仿蛙游动机器人设计的关节式气动软体致动器的可行性．     

自传感介电弹性体执行器的动力学设计及应用

本文提出了一种传感与作动一体化的介电弹性体(DE)软执行器,可用于薄膜结构形面变形的同步测量和控制.首先,建立DE软执行器电致驱动过程的动力学模型,描述其力电耦合行为.其次,通过开展动态作动实验,辨识该动力学模型的参数.第三,分析不同参数对作动器动态响应的影响,以理解其基本动力学特性.第四,建立DE软执行器自传感过程的简化电路模型,并对其电学参数与位移之间的关系进行实验标定.最后,开展平面薄膜结构的形面位移自适应调整实验,并设计相应的控制策略.实验结果表明,该DE软执行器在作动和传感方面均具有较高精度.因此,其在构建高精度空间薄膜天线方面具有较好的应用前景.     

Paired-wire carrying current actuators and piezoelectric beam sensors for microelectromechanical systems

Microsystem Technologies - An alternative actuator for MEMS/NEMS device is proposed and analyzed. The actuator is based on the paired-wires (PW) carrying current concept, which makes the actuator...     

The gas flow rate increase obtained by an oscillating piezoelectric actuator on a micronozzle

Micronozzles with piezoelectric actuator were fabricated and investigated. The micronozzles were fabricated in glass substrates using a powder-blasting technique, and the actuator is a bimorph structure made from a piezoelectric polymer. The actuator was located at the nozzle outlet, and was driven in an oscillating mode by applying an alternating voltage across the actuator electrodes. With a pressure difference between inlet and outlet, the gas flow rate through the device was increased. This effect was quantified, and compared to a similar micronozzle with no actuator. The increase in the flow rate was defined as the gas flow through the micronozzle with actuator oscillating minus the gas flow without actuator, was found to depend on the inlet pressure, the pressure ratio, and the nozzle throat diameter.     

Integration of displacement sensor into bulk PZT thick film actuator for MEMS deformable mirror

Bulk PZT thick film actuator integrated with displacement sensor, the so-called self-sensing actuator, is presented in this paper. The PZT film is used as not only an actuating layer but also a displacement sensor, which is achieved by dividing the electrode on the top surface of the PZT film into two parts: central top electrode for actuating and outer annular sensor electrode for piezoelectric displacement detection. When the actuator moves, the piezoelectric charge is induced in the outer annular PZT due to the piezoelectric effect. The total amount of accumulated charge is proportional to the stress acting on the PZT, which is in turn proportional to the actuator displacement. By collecting the piezoelectric charge, the actuator displacement can be detected. A theoretical model is proposed to determine the structure parameters of the sensor and predict the sensor sensitivity. Experiments were performed on the micro-fabricated sensor integrated PZT thick film actuator, and the measured piezoelectric charge is close to the theoretical predictions. The integrated piezoelectric sensor has a displacement sensitivity of approximately 4 pC/nm. In addition, the integration of displacement sensor into the actuator needs no additional fabrication process and has no influence on the actuator performances.