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...     

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.     

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.     

显微外科手术机器人手指系统的研究与开发

显微外科手术机器人手指系统是在显微外科手术机器人（妙手系统）的研制过程中,针对手术的自身特点及操作要求而自主开发的．该手指系统体积小、重量轻、夹持力大、机构精简、可靠性高,可以准确实现工具的旋转与开合,能够迅速地更换末端手术工具．通过一系列的试验测试及动物试验的研究,结果表明该手指系统的设计是成功的,能够满足显微外科手术的操作要求．     

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.     

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     

Design process and simulation testing of a shape memory alloy actuated robotic microgripper

Microgrippers are commonly used for micromanipulation of micro-objects with dimensions from 1 to 100 µm and attain features of reliable accuracy, low cost, wide jaw aperture and variable applied force. This paper studies the design process, simulation, and testing of a microgripper which can manipulate and assemble a platinum resistance temperature probe, made from a 25 µm diameter platinum wire, a 20 mm diameter tinned copper wire, and a printed circuit board type connector. Various microgripper structures and actuator types were researched and reviewed to determine the most suitable design for the required micromanipulation task. Operation tests using SolidWorks and ANSYS software were conducted to test a parallelogram structure with flexible single-notch hinges. The best suited material was found to be Aluminium alloy 7075-T6 as it was capable of producing a large jaw tip displacement of 0.7 mm without exceeding its tensile yield strength limit. A shape memory alloy was chosen as a choice of actuator to close the microgripper jaws. To ensure a repeatably accurate datum point, the final microgripper consisted of a fixed arm and a flexible arm. An optimisation process using ANSYS studied the hinge thickness and radius dimensions of the microgripper which improved its deflection whilst reducing the experienced stress.

     

基于柔性铰链的热驱动微夹钳的实验和仿真分析

微执行器在整个微机电系统中直接面对其应用对象,需要满足定位精度高,稳定性好,响应速度快,控制方便的要求.柔性铰链以其特殊的性能广泛应用于操作执行器的设计应用中.以一种基于柔性铰链的电热驱动微夹钳为研究对象,通过实验和ANSYS有限元仿真分析对微夹钳的机械性能进行了分析,发现微夹钳端部的输出位移与输入电压基本呈线形关系.通过仿真分析探讨了柔性铰链结构尺寸变化对微夹钳性能的的影响.     

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.     

Development of a piezoelectric polymer-based sensorized microgripper for microassembly and micromanipulation

This paper presents the design, fabrication, and calibration of a piezoelectric polymer-based sensorized microgripper. Electro discharge machining technology is employed to fabricate the superelastic alloy-based microgripper. It was experimentally tested to show the improvement of mechanical performance. For integration of force sensor in the microgripper, the sensor design based on the piezoelectric polymer polyvinylidene fluoride (PVDF) film and fabrication process are presented. The calibration and performance test of the force sensor-integrated microgripper are experimentally carried out. The force sensor-integrated microgripper is applied to fine alignment tasks of micro opto-electrical components. Experimental results show that it can successfully provide force feedback to the operator through the haptic device and play a main role in preventing damage of assembly parts by adjusting the teaching command.The authors wish to thank Mr. Sang-Min Kim for technical assistance. This work was supported by the 21st Centurys Frontier R&D Projects, under the contract number MS-02–324–01, sponsored by the Ministry of Science and Technology, Korea.     

A microgripper using piezoelectric actuation for micro-object manipulation

Design, fabrication and tests of a monolithic compliant-flexure-based microgripper were performed. The geometry design and the material stresses were considered through the finite element analysis. The simulation model was used to study in detail profiles of von Mises stresses and deformation. The maximum stress in the microgripper is much smaller than the critical stress values for fatigue. The microgripper prototype was manufactured using micro-wire electrode discharge machining. A displacement amplification of 3.0 and a maximum stroke of 170 μm were achieved. The use of piezoelectric actuation allowed fine positioning. Micromanipulation tests were conducted to confirm potential applications of the microgripper with piezoelectric actuation in handling micro-objects. The simulation and experimental results have proven the good performance of the microgripper.     

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]     

Electrothermoelastic modeling of MEMS gripper

The design of many thermal Microelectromechanical (MEMS) actuators is often based on finite element analysis, but lacks analytical insight. In this paper we report a novel electro-thermal microgripper and a comprehensive thermal modeling of a general 5 lineshape microbeam’s actuator using 1-D steady state heat equations. Because of the variety of microgripper fabrication technologies and their applications, different thermal boundary conditions are considered for lifted off and attached grippers. Parametric and nonparametric electrothermomechanical identification models for silicon on insulator microgripper, fabricated on 100 μm device layer, are obtained.     

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.     

基于视觉的微夹钳位移测试技术研究

微夹钳输出位移是它的一个重要特性,微夹钳整体尺寸比较小,不能用常规方法测量输出位移.针对微夹钳的特点,提出一种微夹钳位移测试方法,采用非接触式测量,设计了一种基于视觉的微位移测试装置,并开发了配套的测量软件.测试软件通过LabVIEW软件平台实现,能够实现图像标定、测量和图像标注等功能.给出了详细的图像标定方法,通过台...     

Multi-objective optimization design for a sand crab-inspired compliant microgripper

A large working travel and a minimal stress are the most critical characteristics of a microgripper but they are conflicted each other. This paper develops a new efficient hybrid algorithm to solve the multi-objective optimization design for a sand bubbler crab-inspired compliant microgripper. The structure of sand bubbler crab-inspired compliant microgripper is inspired from the profile of sand bubbler crab. A surrogate-assisted multi-objective optimization is conducted by developing a hybrid approach of finite element analysis, response surface method, Kigring metamodel and multi-objective genetic algorithm. First, the data are collected by integrating the finite element analysis and response surface method. Subsequently, in the types of common surrogates, Kigring metamodel is adopted as an efficient tool to approximate the objective functions. And then, the Pareto-optimal fronts are found via the multi-objective genetic algorithm. The results indicated that the optimal results are at the displacement of 5999.9 µm and stress of 330.68 MPa. The results revealed that the optimized results are highly consistent with both the validation results. The accuracy of the surrogate models showed that the regression model is a good prediction. The proposed approach is useful tool to solve complex optimization designs.

     

A multipurpose electrothermal microgripper for biological micro-manipulation

A novel electrothermal SU-8 microgripper with a large gripping scope and multipurpose jaws is designed and ANSYS software was used to check its performances. Then, the microgripper is fabricated by a simple UV-LIGA process followed by two performance tests. The static test results show that with only 195 mV, 111.1 mW and 53.7 °C temperature increase at the actuator, a 71.5 μm jaws gap change is obtained. The dynamic response test result shows that driven by different step-type voltages, the response time is about 0.23 s during both closing and opening jaws process. Finally, two micro-manipulation sequences are carried. The experimental results show that due to the large gripping scope and the multipurpose jaws, the microgripper can be used as a multipurpose manipulator for biological micro-manipulations including the manipulation of micro blood vessel and the operation of small size cell, such as cyanobacteria cell.     

一种集成微力检测的压电式微夹钳

针对微装配任务设计了一种双悬臂梁结构的压电双晶片微夹钳,该微夹钳由两个压电双晶片驱动．建立了压电双晶片的复合梁模型,并对它的微位移—电压特性、夹持力—应变特性进行了数学分析．通过检测悬臂梁根部的应变信号实现对微夹钳夹持力的检测．实验证明该微夹钳工作可靠,能够满足微装配机器人装配任务的要求．     

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...     

Principle of a Submerged Freeze Gripper for Microassembly

The development of reliable and repeatable strategies to manipulate and assemble microobjects lies in the efficiency, reliability, and precision of the handling processes. In this paper, we propose a thermal-based microgripper working in an aqueous medium. Manipulating and assembling in liquid surroundings can indeed be more efficient than in dry conditions. A comparative analysis of the impact of dry and liquid media on surface forces, contact forces, and hydrodynamic forces is shown. In addition, ice grippers represent flexible manipulation solutions. Nevertheless, when micromanipulation tasks are performed in air, capillary forces can drastically perturb the release. Our submerged freeze microgripper exploits the liquid surroundings to generate an ice droplet to catch microobjects, and to avoid capillary forces during the release. The thermal principle, the first microgripper prototype, an ice generation simulation, and the first tests are presented. The main objective is to validate the manipulation principle. Further research will be focused on control and optimization of the ice generation and the miniaturization of the system.