基于有限元分析的ICF靶半自动装配系统的微夹钳设计

根据惯性约束聚变(ICF)靶零件的特点,确定用于ICF靶半自动装配系统微夹钳的技术指标,并完成其结构设计.该微夹钳采用柔性铰链机构和压电陶瓷驱动,可根据需要更换不同形状和开口距离的夹口,以适应夹持不同靶零件.以压电陶瓷的2种极限参数为载荷,分析了微夹钳的张合量、应力分布、应变量,并采用非线性接触分析对夹持力和夹持效果进...     

夹钳式力反馈遥微操作系统的设计与试验

研制一种夹钳式的力反馈遥微操作系统,包括夹钳式主手、由压电陶瓷驱动的微夹持器和主从式力反 馈控制模块．该系统可使操作者在遥微操作中具有夹持力觉临场感,避免破坏易碎的操作对象．详细介绍了夹钳式 主手、从手和力反馈的设计与控制方法,并搭建试验平台进行遥微操作试验,分析了主手和从手之间的位置跟踪、 力反馈和时滞特性．制作和试验结果验证了系统方案的可行性,为进一步将遥微操作应用于微装配和其他领域提供 参考．     

一种带力传感的微夹持器设计及试验

设计制作一种带力传感的微夹持器,通过压电陶瓷堆驱动和柔性铰链放大来实现夹持动作,由粘贴于悬臂应变梁的半导体应变片构成惠斯通电桥测量微夹持力．优化设计了柔性铰链的结构,对悬臂式应变梁进行了仿真分析．最后,制作并组装成微夹持器,进行了力传感标定试验和微夹持操作试验．制作和试验结果验证了这种带力传感的微夹持器的可行性和实用性．     

一种基于MEMS技术的压电微泵的研究

介绍了一种基于MEMS技术的压电微泵。该微泵利用聚二甲基硅氧烷(PDMS)作为泵膜,使用了一个主动阀和一个被动阀,并利用压电双晶片作为驱动部件。压电双晶片和PDMS泵膜的组合可以产生较大的泵腔体积改变和压缩比,显著降低了加工成本,并提高了成品率。对压电微泵的输出流量进行了测试,结果显示:电压、频率以及背压对流量均有显著影响。在100 V,25Hz的方波驱动下,该压电微泵的最大输出流量为458μL/m in,最大输出压力为6 kPa。     

毫米级全方位移动微型装配机器人设计、运动学分析与控制

介绍了一种用于微型工厂的毫米级移动微装配机器人,其具有独特的全方位运动结构．微机器人由4个直径3 mm的电磁微马达驱动,并装备有一对微型夹钳．通过分析运动学矩阵的秩,证明了微机器人的全方位特性,并建立了微夹钳的运动学方程．设计了基于计算机视觉的微机器人控制系统,给出了微机器人定位和驱动方法．实验证明了微机器人的负载能力、机动性以及控制系统的有效性．     

集成位置/力传感器的桥式压电微夹持器

针对微操作和微装配任务中起着至关重要作用的微夹持器的设计问题,考虑其对大行程、平动夹持和集成位置/夹持力检测的要求,采用桥式放大机构和平形四边形机构,设计了一种柔顺压电微夹持器.根据机械原理和柔顺机构学,推导了微夹持器的理论放大倍数、固有频率和输出耦合比.然后通过ANSYS软件,对微夹持器的放大倍数、固有频率和输出耦合比进行了仿真,最后建立了实验测控系统来验证该微夹持器的性能.实验结果表明:该微夹持器的夹持范围为0.345μm~328.2μm,放大倍数为16.4,固有频率为157.5 Hz,ANSYS仿真与实验测得的放大倍数和固有频率的相对误差分别为17.7%和12.9%,实验结果验证了理论模型和有限元仿真的正确性,实现了大行程、平动夹持和集成位置/力传感器的设计目标.     

双晶片悬臂梁式压电传感器的有限元仿真研究

压电传感器作为一种便捷、高效的传感器类型,越来越受到人们的青睐.为研究压电传感器机电耦合能力,将压电高聚物聚偏氟乙烯(PVDF)黏结而成的压电双晶片悬臂梁作为研究对象,利用有限元分析软件ANSYS Workbench,首先完成对模型的构建和模态分析,得出模型的固有频率和固有振型,再建立压电材料的压电本构方程,对压电双晶片悬臂梁模型发电量进行模拟仿真,最后将仿真结果与前人研究结果相对比.分析得出:在10 mm的形变量下,能够产生最大320 V左右的瞬时电压,这与前人的研究结果相近,验证了仿真结果的准确性,同时也证实了压电双晶片悬臂梁作为压电传感器的可行性.     

基于双晶片压电传感器特性分析

用模态分析法分析双晶片压电力、振动、位移传感器的位移特性及灵敏度特性,并给出灵敏度与压电材料参数及晶片几何尺寸的关系。其仿真分析结果对压电双晶片用于力、振动、位移等传感器的设计具有重要意义。     

压电双晶片传感器灵敏度特性分析

本文用模态分析法详细分析了压电双晶片力、振动、粗糙度传感器的位移特性及灵敏度特性,并给出了灵敏度与压电材料参数及晶片几何尺寸的关系。     

轴向预压缩压电双晶片驱动器静动态特性仿真

研究轴向预压缩力增大压电双晶片驱动位移及力矩问题,对某微型飞行器的压电双晶片驱动器进行了机电耦合场有限元仿真,得到在不同轴向力及电压作用下的静动态特性。为了验证系统可靠性,采用解析解进行比较,结果表明:有限元解和解析解复合较好。采用上述压电双晶片驱动器,在150V电压及25N轴向力的作用下,驱动转角峰峰值为14°,驱动力矩为2.4N*mm,都达到未施加轴向力的压电双晶片驱动器的4倍以上。一阶固有频率为95Hz远大于普通电动舵机,可大幅提高微型飞行器的操稳性。     

Interval force/position modeling and control of a microgripper composed of two collaborative piezoelectric actuators and its automation

This paper deals with the modeling and control of a microgripper devoted to micromanipulation and microassembly applications and tasks. Based on two collaborative piezoelectric actuators, the microgripper is typified by a high sensitivity to the environment, in particular a high sensitivity to the properties of the manipulated objects. This sensitivity makes the behavior of the microgripper variable and uncertain versus the environment and consequently makes the tasks lose performances. A possible way to overstep that problem is to model the microgripper behavior and its dependency with the environment as perfect as possible and then calculate a controller from this. However, such model is complex to handle and the yielded controllers are often very complex for implementation. In this paper, we propose to use interval models to describe the behavior of the piezoelectric actuators that compose the microgripper. Then a controllers synthesis consisting in combining interval techniques and classical control theory is proposed. Both the position and the force raised in the microgripper are considered. The main advantages of the proposed technique are: 1) ease and natural way to model the uncertainties, 2) the robustness of the synthesized controllers, 3) and the derivation of low order controllers that are easier for implementation relative to those of classical robust control techniques. Finally, the paper presents the application of the controlled microgripper to an automated pick-transport-andplace task of micro-objects. This automated task demonstrates the efficiency of the control technique in micromanipulation and microassembly applications.     

Microgrippers created in microstructurable glass

 In this paper a new microgripper will be presented. The specific feature is the microfabrication based on a UV-lithographic process in microstructurable, photosensitive glass. Technological and manufacturing problems of the gripper will be described. The developed microgripper is actuated by a piezoelectric ceramic (monomorph). Glass microstructures are used as solid state hinges. With the special design of the gripper it is possible to realise a high distance ratio. The deflection of the gripping arms is some hundred micrometers. The gripping forces are a few mN up to 50 mN. The new grippers were fabricated and tested successfully. Received: 20 December 1996/Accepted: 9 January 1997     

A novel electrostatic based microgripper (cellgripper) integrated with contact sensor and equipped with vibrating system to release particles actively

This paper presents design and simulation of a novel electrostatic microelectromechanical systems gripper with an integrated capacitive contact sensor. Moreover, this microgripper is able to employ vibration to release micro objects (cells) actively. Lateral comb drive system is used to close the gap between the gripper arms and hold the objects while the transverse comb differential capacitances act as a contact sensor to prevent damaging the fragile micron-sized particles specifically biological cells. In addition, the capability of the microgripper in generating vibration at the end-effectors electrostatically is an advantage to facilitate releasing process by overbalancing the adhesion forces between the particle and the gripper arm. Finite element analysis based simulations are carried out to estimate the behavior of the microgripper while the standard SOI-MUMPs micromachining process is proposed for fabrication of the microgripper.     

A self-centering electrostatic microgripper

Automated microassembly of micro hybrid devices is one fundamental step to reduce their high cost. Often, microassembly deals with fragile and wear-sensitive microparts that must be accurately grasped, positioned, and released or fastened in stable positions. The requirements of reliable, flexible, and fast assembly devices are other important characteristics to be achieved. This paper deals with the design of an electrostatic gripper that can grasp standard microcomponents and delicate mini and micro parts alike. The aim of this work is to theoretically and experimentally demonstrate the good performance of a self-centering gripper based on electrostatic forces. This paper extends previous works concerning electrostatic handling by adding new theoretical and FEM models, further tests, and new interpretations of the gripper’s grasping and centering capabilities. The design of the gripper is justified and supported by theoretical considerations. To better evaluate the generated force and the influences of the component on the gripper performance, FEM models are presented.     

Design enhancement of a chevron electrothermally actuated microgripper for improved gripping performance

In this paper design modifications are proposed in microgripper design using two in-plane chevron electrothermal actuators. The design modifications are, converting free–free gripping arm into a clamped-free gripping arm and inclusion of the heat sinks in the shuttle. The modified design provides reduced temperature at the gripping jaws and higher gripping force. The proposed microgripper is modelled analytically and numerically using MEMS CAD tool CoventorWare. The performance of the microgripper such as displacement, force and temperature for the voltage range of 0–1.2 V is evaluated through numerical and analytical simulation. The results demonstrate the feasibility of fabrication. Further the gripper is made of polysilicon which allows operating the gripper at lower voltage.     

Electrothermally Activated SU-8 Microgripper for Single Cell Manipulation in Solution

The development of a SU-8-based microgripper that can operate in physiological ionic solutions is presented. The electrothermally activated polymer gripper consists of two “hot-and-cold-arm” actuators that are fabricated in a two-mask surface micromachining process. The high thermal expansion coefficient of SU-8 (52$ ppm/^circ C$) compared to silicon and metals, allows the actuation of the microgripper with small average temperature elevations (10 – 32$^circ C$) at low voltages (1–2 V). The polymer microgripper can be used for the manipulation of single cells and other biological species in solution with minimal undesired interactions.hfillhbox[1330]     

Microassembly of 3-D microstructures using a compliant, passive microgripper

This paper describes a novel microassembly system that can be used to construct out-of-plane three-dimensional (3-D) microstructures. The system makes use of a surface-micromachined microgripper that is solder bonded to a robotic manipulator. The microgripper is able to grasp a micropart, remove it from the chip, reorient it about two independent axes, translate it along the x, y and z axes to a secondary location, and join it to another micropart. In this way, out-of-plane 3-D microstructures can be assembled from a set of initially planar and parallel surface micromachined microparts. The microgripper is 380 /spl times/ 410 /spl mu/m in size. It utilizes three geometric features for operation: 1) compliant beams to allow for deflection at the grasping tips; 2) self-tightening geometry during grasping; and 3) 3-D interlocking geometry to secure a micropart after the grasp. Each micropart has three geometric features built into its body. The first is the interlock interface feature that allows it to be grasped by the microgripper. The second is a tether feature that secures the micropart to the substrate, and breaks away after the microgripper has grasped the micropart. The third is the snap-lock feature, which is used to join the micropart to other microparts.     

Modeling of a three-layer piezoelectric bimorph beam withhysteresis

Piezoelectric actuators are usually stacked or bimorph in configuration. In this paper the mechanics of a three-layer piezoelectric bimorph is discussed and its dynamic model with hysteresis is presented. The results can be used to analyze piezoelectric actuators constructed with three-layer piezoelectric bimorphs. A piezoelectric bimorph actuator has been fabricated and experiments have been carried out to verify the model. The calculated results of this model closely matched the tested results. This model can also be used with other types of piezoelectric actuators with a slight modification     

Design, implementation and testing of electrostatic SOI MUMPs based microgripper

This paper presents a detail modeling, finite element analysis and testing results of MEMS based electrostatically actuated microgripper. Interdigitated lateral comb pairs have been used to actuate the microgripper. The microgripper is optimized using standard SOI-MUMPs technology in L-Edit of MEMS-Pro with dual jaws actuation at low voltages. Coupled electromechanical finite element analysis performed in COVENTOR-WARE shows total displacement of 15.5 μm at jaws tip at 50 V, which is quite comparable to experimental result of 17 μm displacement at the tip of gripper jaw for the same voltage. Micromanipulation experiments have successfully demonstrated the gripping, holding micro-objects between 53 and 70 μm in size. The simulated model is used to study detail profile of Von Mises stresses and deformations in the model. It is noted that maximum stress in microgripper is 200 MPa which is much smaller than yield stress of 7 GPa. The slight difference between finite element analysis and experimental results is because of small variations in process material parameters. The total size of gripper is 5.03 × 6.5 mm².     

Silicon-processed overhanging microgripper

A silicon-processed microgripper, suitable for mounting on a micropositioner, has been designed and fabricated by combining surface and bulk micromachining. The microgripper consists of a silicon die (7 mm×5 mm), a 1.5 mm long support cantilever, made from boron-doped silicon substrate material (protruding from the die), and a 400 μm long polysilicon overhanging gripper extending from the end of the support cantilever. The microgripper is electrostatically driven by flexible, interdigitated comb pairs and has significantly smaller feature sizes than have been reported previously for overhanging microstructures. Problems addressed successfully in the microgripper fabrication include the protection of surface-micromachined fine structures during bulk-silicon etching and rinsing. The microgripper has successfully seized several microscopic objects in laboratory experiments