Development of a novel protective cover for micro manipulation process in the SEM chamber

This paper presents a novel approach to assembly of micro components in a scanning electron microscope (SEM) chamber. A new set, called Protective Cover for micro components allows their quick positioning on the platform inside the SEM chamber without gluing. It is well known that the vacuum pumps, especially turbo one, which evacuated a SEM chamber, are highly sensitive to foreign object damage. This is the reason why the micro components are glued on the specimen holder in the SEM chamber. On the other hand, the grippers that have to pick, lift and place the micro components in a desired system (position, orientation) are very fragile. They can not overcome the adhesive force of the glue and remove the particle from the specimen holder. The presented system is standardized and can be mounted without additional time, modification or expenses into the SEM chamber. It enables, on the one hand, easier manipulation of the micro components that do not need to be glued on the specimen holder and, on the other hand, introduces further automation in the manipulation process in the SEM chamber since it creates thus a necessary basis for modular assembling system. Furthermore, it is very important for the automated assembly process that the micro components are exactly positioned. The standardization in the micro world becomes more and more essential. The uniformity of parts, operations and tools strongly supports an automatic assembly system.     

SCARA based peg-in-hole assembly using compliant IPMC micro gripper

Robotic assembly is difficult as there always exist position errors between two mating parts. Compliance is added in a selective compliant assembly robot arm (SCARA) in the form of a two ionic polymer metal composite (IPMC) fingers based micro gripper. This micro gripper is integrated at the end effector position of a SCARA robot. Peg-hole interaction is analytically modeled and based on it the force required to correct the lateral and angular errors by IPMC is calculated. A proportional-derivative (PD) controller is designed to actuate the IPMC to get the desired force for correcting the peg position before assembly. Simulations and experiments were carried out by developing an IPMC micro gripper and using it to analyze various cases of peg in hole assembly. The experimental results prove that adding compliance through IPMC helps in peg-in-hole assembly.     

Micro parts assembly system with micro gripper and RCC unit

This paper presents a new micro assembly system, which is composed of a micro gripper, a micro remote center compliance (RCC) unit, a voice coil motor-driving mechanism and precision motion stages. The micro gripper is actuated by two shape memory alloy (SMA) wires, and its grip is 1 mm. The micro RCC unit has low translational and rotational stiffness sufficient for micro parts assembly. The voice coil motor-driving mechanism can generate linear motion with an adjustable stiffness, and it can also measure external force in the moving direction. An algorithm for the automatic assembly of micro parts is also proposed, and assembly experiments are performed.     

Design and manufacturing of mobile micro manipulation system with a compliant piezoelectric actuator based micro gripper

This paper presents a new design of mobile micro manipulation system for robotic micro assembly where a compliant piezoelectric actuator based micro gripper is designed for handling the miniature parts and compensation of misalignment during peg-in-hole assembly is done because piezoelectric actuator has capability of producing the displacement in micron range and generates high force instantaneously. This adjusts the misalignment of peg during robotic micro assembly. The throughput/speed of mobile micro manipulation system is found for picking and placing the peg from one hole to next hole position. An analysis of piezoelectric actuator based micro gripper has been carried out where voltage is controlled through a proportional-derivative (PD) controller. By developing a prototype, it is demonstrated that compliant piezoelectric actuator based micro gripper is capable of handling the peg-in-hole assembly task in a mobile micro manipulation system.     

Development of Multi Micro Manipulation System Using IPMC Micro Grippers

This paper presents a new design of multi micro manipulation system using ionic polymer metal composite (IPMC) micro grippers for robotic micro assembly where IPMC is used as a light weight actuator for developing the micro grippers. It has the potential of large displacement, low mass force generation and misalignment compensation ability during micro manipulation. These capabilities are utilized for handling of miniature parts like pegs. The analysis of IPMC micro gripper and manipulator are carried out for developing a multi micro manipulation system that can handle pegs in micro assembly operation for shifting one to another hole position in a large work space (100 mm × 100 mm). By developing a prototype, it is demonstrated that IPMC based micro grippers are capable of handling the peg-in-hole assembly tasks in a multi micro manipulation system.     

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.     

Equipment technology for flexible and automated micro-assembly

Micro-assembly differs from conventional assembly in terms of the size and characteristics of the objects involved. As a result the requirements relating to handling precision are so high that it is often very difficult to achieve them with manual operations. These extremely challenging requirements usually relate to environmental conditions and adjustable gripper tools, frequently equipped with a range of sensors. The extensive automation of micro assembly is therefore desirable for both cost and performance.     

Methods for highly accurate gripping of flexible micro parts

Today, handling and assembly of flexible micro-components such as thin wires or glass fibres with diameters down to a few micrometers and lateral dimensions up to a few meters is an important challenge in hybrid micro-assembly (Brecher and Peschke 2004). Production of flow sensors for respirators in medical engineering or coupling a fibre to an active visual component in optical data communication are examples of such applications. Such products have one thing in common: The assembly of their most sensitive functional components is often carried out manually since the handling and positioning technology either has to be specially developed and is costly or is non-existent (Weck and Peschke 2003). However, in most cases the manual assembly is very time consuming and its repeatability and positioning accuracy is not adequate (Carrozza et al. 2000); Petersen (2003). This disadvantage is obvious especially in the assembly of hybrid micro-optical telecommunication systems such as switches or power splitters, because the required mounting tolerances are less than a micron. A deviation of 100 nm in the alignment between the optical components and the glass fibres leads to noticeable and non-tolerable losses when coupling light into the fibres. With this background, fundamental studies are carried out at Fraunhofer IPT for the optimization of gripper geometry, gripper materials and gripping parameters for handling flexible micro-components such as glass fibres. The aim of these studies, shown in chapter 2 of this paper, is primarily to investigate the effects on the reproducibility of the positioning when gripping these highly sensitive micro-components and to derive gripper optimization strategies. A further aim is to develop a large scale integrated, adaptive, rugged and economical gripper system particularly for handling and alignment of flexible micro-components accurate to the sub-micron level. This gripper system can be used on conventional robot systems for carrying out micro-assembly operations. The robot system carries out the pre-positioning, the positioning tolerances necessary for the micro-assembly are subsequently realised directly at the tip of the gripper with a multi-axes system integrated into the gripper. Positioning systems that achieve the required positioning increments in the sub-micron range are existent (Scheller 2001). The problem of such systems is that they are normally highly sensitive against mechanical impact. Also their gripper integration is problematical due to a high weight and size dimensions in the decimetre range for each axis. In this paper the development of a highly robust gripper-integrable multi-axes system is presented.     

Assembly and measuring technique for the manufacturing of active micro systems

This paper presents the current results of the development of an assembly equipment with integrated measuring system that will permit a high position accuracy. The kernel of the work is an parallel robot, an innovative optical sensor for 3 dimension and an micro gripper.     

用于长期神经元放电记录的一体化可步进植入式神经电极

步进式电极是神经科学电生理记录的重要工具。传统电极支架的主要功能是电极丝支撑以及机械驱动电极丝的微推进。在慢性记录过程中，电极的位置可以推进到更深的脑组织中，从而记录更多的神经元放电活动。但传统电极支架制作和组装需要多个步骤和部件，组装过程烦琐困难、结构集成度低，且无法保证支撑板结构之间相互平行，增加了实验误差。该文提出一种可实现集成度高、结构稳定、组装容易的新型电极构架。与传统电极支架相比，新设计的电极支架具有更少的组件，且一体化的支架设计减少了不同支架之间的误差，有助于实验条件的统一。受力分析表明，该文提出的新电极具有优良的抗形变特性，且新电极比传统电极重量更小，可减轻实验小鼠头部负载压力。通过手术在小鼠大脑中植入电极，实验结果表明一体化记录电极可获得高质量的神经信号。因此，该文提出了一种新的电极设计思路，该思路有助于提高实验效率，并可应用于多种小动物在体电生理实验。     

Hybrid universal handling systems for micro component assembly

Highly sophisticated machining techniques make it possible to manufacture ultra precise micro components as small as 100 μm3. These micro components are normally mounted onto larger macroscopic components before being incorporated into, e.g., medical, telecommunication or sensor technology products. In view of the highly inflexible systems currently available, the work carried out by the Fraunhofer IPT with funding from the SFB 440 focuses on the development of a hybrid, universally applicable fine positioning system. The system consists of an assembly head which, with the aid of an integrated six-axis fine positioning unit and an integrated sensor unit for referencing the assembly position, gives a conventional positioning system such as an articulated robot arm the ability to perform highly precise micro assembly processes. This provides the context for the development work carried out by the Fraunhofer IPT into assembly head design concepts. The first step involved investigating the positioning behavior of a conventional articulated robot arm, and then analyzing the demands placed on the assembly head. This is followed by the development and optimization of the miniaturized guidance, actuator and sensor components that are needed for the construction of a robust, highly precise six-axis fine adjustment system. The result of this work includes a set of linear guides, the size of a matchbox, with air bearings. The prototype guides set up at the Fraunhofer IPT have a non-contact interface, which makes it possible to convey compressed air without friction or force.     

Parallel precision alignment of multiple micro components

Micro components are available in a variety of shapes sizing from 1 mm down to 0.01 mm. Today, their mass production is quite common using state of the art production technology. Micro spheres for example, are on the one hand available in lot sizes up to some thousands in a constant quality within micron accuracy. On the other hand they are quite commonly provided as bulk material with diameter variations of up to 10% in each lot size Brandau (Chem Ingenieur Tech 75:1741–1745, 2003). In both cases, the bulk micro components are usually arranged in incoherent batches which are packed in plastic bags or small jars for handling and shipping. The decollating of the single components for follow-up micro assembly processes is complicated by the well-known effects in micro handling such as dominating adhesion and friction forces (Petersen 2003). These effects limit the post processing of bulk micro components to manual work in order to sort and align the single micro components prior to their exposure to an automated assembly line. To enable a sophisticated and automated handling of the single micro components, automated sorting and alignment mechanisms are necessary to arrange the bulk micro components in a well defined pattern structure which is essential to realize an efficient automated micro assembly.     

Easily manageable, electrothermally actuated silicon micro gripper

This paper presents a new batch process to fabricate thermally driven silicon micro grippers for handling and manipulation objects smaller than 25 μm. To achieve a robust gripper gearing with fine gripping tips, silicon on insulator (SOI) technology is used. The flexure gearing is driven by two integrated thermal expansion actuators that are moving in opposite directions and are actuated by Joule heating. In addition, a customized gripper mounting mechanism is presented, which offers fast and easy gripper handling, resulting in reduced tooling time and lower costs for the user. Finally, the experimental results and electrical characteristics for the sophisticated gripper design are presented.     

Design,fabrication, and testing of a 3-DOF HARM micromanipulator on (1 1 1) silicon substrate

In this study, a novel HARM (high aspect ratio micromachining) micromanipulator fabricated on (1 1 1) silicon wafer is reported. The micromanipulator consists of a positioning stage, a robot arm, supporting platforms, conducting wires, and bonding pads. These components are monolithically integrated on a chip through the presented processes. The three-degrees-of-freedom (3-DOF) positioning of the micromanipulator is realized by using the integration of two linear comb actuators and a vertical comb actuator. The robot arm is used to manipulate samples with dimension in the order of several microns to several hundred microns, for instance, optical fibers and biological samples. The robot arm could be a gripper, a needle, a probe, or even a pipette. Since the micromanipulator is made of single crystal silicon, it has superior mechanical properties. A micro gripper has also been successfully designed and fabricated.     

Orienting polygonal parts without sensors

In manufacturing it is often necessary to orient parts prior to packing or assembly. We say that a planar part ispolygonal if its convex hull is a polygon. We consider the following problem: given a list ofn vertices describing a polygonal part whose initial orientation is unknown, find the shortest sequence of mechanical gripper actions that is guaranteed to orient the part up to symmetry in its convex hull. We show that such a sequence exists for any polygonal part by giving anO[n ² logn) algorithm for finding the sequence. Since the gripper actions do not require feedback, this result implies that any polygonal part can be orientedwithout sensors.This report describes research conducted in part while the author was a graduate student supported by NSF Grant DMC-8520475 and NASA-Ames Grant NCC 2-463 at the School of Computer Science at Carnegie Mellon University. The author is currently supported by a grant from the Faculty Research Initiation Fund at the University of Southern California.     

A rotary comb-actuated microgripper with a large displacement range

This paper reports a novel design for electrostatic microgrippers. The new structure utilizes rotary comb actuators to solve the pull-in problem of microgrippers during large displacement manipulation and therefore avoids the widely used conversion systems which necessitate a high driving voltage. The gripper is fabricated using a SOI process with a 60 μm structural layer. Test results show the gripper obtained a displacement of 94 μm with an applied voltage of 100 V. An animal hair is gripped to demonstrate the applicability of the gripper for micro object manipulations.     

Design of a low-cost five-finger anthropomorphic robotic arm with nine degrees of freedom

The aim of this work was to design and demonstrate a dexterous anthropomorphic mobile robotic arm with nine degrees of freedom using readily available low-cost components to perform different object-picking tasks for immobile patients in developing nations. The robotic arm consists of a shoulder, elbow, wrist and five-finger gripper. It can perform different gripping actions, such as lateral, spherical, cylindrical and tip-holding gripping actions using a five-finger gripper; each finger has three movable links. The actuator used for the robotic arm is a high torque dc motor coupled with a gear assembly for torque amplification, and the five-finger gripper consists of five cables placed like tendons in the human arm. The robotic arm utilizes a controller at every link to trace the desired trajectory with high accuracy and precision. Digital implementation of the control algorithm is done on an Atmel Atmega-16 microcontroller using trapezoidal approximation and Newton's backward difference methods. The arm can be programmed or controlled manually to perform a variety of object-picking tasks. A prototype of the robotic arm was constructed, and test results on a variety of object-picking tasks are presented.     

Research on vacuum gripper based on fuzzy control for micromanipulators

This paper presents a vacuum gripper （as an actuator of an intelligent micromanipulator） for micro objects （with a diameter of 100 - 300μm） assembly tasks. The gripper is composed of a vacuum unit and a control unit. The vacuum unit with a proportional valve and a pressure sensor, and the control unit with a PC ＋ MCU two-layered control architecture are designed. The mechanical structure, workflow and major programs of the micro-gripper are presented. This paper discusses the major components of the adhesion force acting on micro objects. Some equations of the operation conditions m three phases of pick, hold and place are derived by mechanics analysis. The pneumatic system＇s pressure loss is inevitable. There are some formulas for calculating the amount of the pressure loss, but parameters in formulas are diffficult to be quantified and evaluated. To control the working pressure accurately, a pressure controller based on fuzzy logic is designed. With MATLAB＇s fuzzy logic toolbox, simulation experiments are performed to validate the performance of the fuzzy PD controller. The gripper is characterized by a steady and reliable performance and a simple structure, and it is suitable for handling micro objects with a sub-millimeter size.     

Sensor-guided micro assembly of active micro systems by using a hot melt based joining technology

This article presents (the most) recent results of the subprojects B4 and B8 of the Collaborative Research Center 516—Design and Manufacturing of Active Micro Systems—which are concerned with the assembly of active micro systems. While subproject B4 investigates sensor guided assembly processes, subproject B8 develops suitable assembly techniques on the basis of non-viscous adhesive systems (hot melts). Process development focuses on the suitability for automation, process times and the applicability of batch processes. The article discusses certain hot melt application techniques that are suitable for batch production, a sensor-guided assembly system as well as different approaches for heat conduction in an automated assembly process for hot melt coated micro components.     

增敏微型FBG应变传感器设计

提出了一种两端夹持套管封装的光纤Bragg光栅(FBG)应变传感器,其结构包括光纤光栅、夹持套管、尾纤3部分,夹持套管封装的传感器尺寸小,可以改变灵敏度系数,测量精度高,适用于应变较小、受尺寸限制的室内模型试验.测试结果表明:增敏微型FBG应变传感器灵敏度高、低噪、稳定可靠,在标距范围内线性关系良好,线性度均达到0.999以上,制作工艺简单,具有很高的实用价值.