Design and experimental testing of an electro-thermal microgripper for cell manipulation

Microsystem Technologies - This paper presents the design, fabrication and experimental characterization of an electro-thermally actuated microgripper suitable for single-cell manipulation. The...     

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.     

Design of a micro manipulation device for cell microinjection

Microsystem Technologies - Survival rate of the injected cells in microinjection is greatly affected by the injecting position on cells. Here, a PDMS-based microfluidic manipulation device for cell...     

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.

     

Development of a novel flexure-based microgripper for high precision micro-object manipulation

Micro-scaled parts with dimension below 1 mm need to be manipulated with high precision and consistency in order to guarantee successful microassembly process. Often these requirements are difficult to be achieved particularly due to the problems associated with the structural integrity of the grasping mechanism which will affect the accuracy of the manipulation. Furthermore, the object's texture and fragility imply that small perturbation by the grasping mechanism can result in substantial damage to the object and leads to the degradation of its geometry, shape, and quality. This paper focuses on the unification of two designing approaches to develop a compliant-based microgripper for performing high precision manipulation of micro-objects. A combination of Pseudo Rigid Body Model (PRBM) and Finite Element Analysis (FEA) technique has proven to improve the design efficiency by providing the essential guideline to expedite the prototyping procedure which effectively reduces the cost and modeling time. An Electro Discharge Machining (EDM) technique was utilized for the fabrication of the device. Series of experimental studies were conducted for performance verification and the results are compared with the computational analysis results. A high displacement amplification and maximum stroke of 100 μm can be achieved.     

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.     

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.     

Design and fabrication of novel micro electromagnetic actuator

This study designs, fabricates, and characterizes a novel micro electromagnetic actuator comprising a PDMS diaphragm, a polyimide-coated copper micro coil, and a permanent magnet. When an electrical current is passed through the micro coil, a magnetic force is induced between the coil and the magnet which causes the diaphragm to deflect, thereby creating an actuation effect. The experimental results demonstrate that the diaphragm deflection can be accurately controlled by regulating the current passed through the micro coil. It is shown that the maximum diaphragm deflection within elastic limits is 150 μm; obtained by passing a current of 0.6 A through a micro coil with a line width of 100 μm. The micro actuator proposed in this study is easily fabricated and is readily integrated with existing bio-medical chips due to its planar structure.     

Rotational micro actuator for microsurgery

In this paper an innovative hydrostatic micro actuator system for controlling the rotational degree of freedom of microsurgery instruments is presented. From the possible hydrostatic motor designs, an annular gear motor in orbit configuration has been chosen based on its suitability for micro manufacturing. The innovative actuator design includes a rotor-integrated control mechanism for connecting the actuator’s individual positive-displacement chambers. First a macro-model of the new actuator was fabricated and tested. The obtained test results already confirm the functionality and show the actuator’s exciting potential. The important design parameters were identified and a mathematical model was developed and is presented in this paper. Thereby optimized design parameters enable a further miniaturization and the use within minimal invasive surgery tools. A potential application of this novel device is discussed in the context of endovascular and interventional resection treatment. Combined with a shape memory alloy actuator a tool for the resection of calcified aortic valves was developed. Because of its small size it is possible to integrate it into a trocar channel.     

毫米级静电微扑翼驱动器的结构设计、工艺与测试

针对仿昆虫扑翼飞行器核心动力装置——微驱动器的结构特点和研究难点,设计了一种基于静电驱动原理的毫米(mm)级微扑翼驱动器,并针对各个部件研究了整套加工工艺与测试方法.运动优化与升力测试结果表明:微扑翼驱动器(翼展9 mm,重量3 mg)以91 Hz的频率实现了±40°的拍动和±25°的扭转运动,输出1.5 mg的升力,升重较以往静电微扑翼驱动器有大幅提升.研究成果为实现仿昆虫微型飞行器的自主飞行提供了新的方向,并奠定了理论与试验基础.     

一种基于SMA的摆动式驱动器驱动原理及实验

在分析了形状记忆合金(SMA)弹簧电热驱动原理的基础上,对一种差动式关节型SMA驱动器进行了实验研究。实验结果表明:驱动电流和冷却条件对驱动器的摆动周期有很大的影响,增大电流会显著提高SMA驱动器的动作频率,但电流过大,易使SMA失去形状记忆功能,所以,电流应控制在一定的范围之内。驱动器的动作频率还受到冷却速度的制约,加快冷却速度也会提高驱动器的动作频率。     

Design of swing arm type actuator and suspension for micro optical disk drive

One of the trends on information storage device is focused on the development of micro-optical devices with optical flying head (OFH). Many different types of sliders for OFH and optical component systems have been introduced in the literature. However, the important issues on the mechanical system, which consists of suspension, swing arm and voice coil motor (VCM) part has not been discussed up to date. In this research, a swing arm type actuator with suspension for micro optical disk drive is designed and developed, basically focused on the mechanical issues, which should be solved for real application.     

A linear actuator with an SMA clamping mechanism for dual-slider positioning

Microsystem Technologies - In this paper, a linear actuator with a shape memory alloy (SMA) clamping mechanism for dual-slider positioning is proposed by using a single piezoelectric element (PZT)....     

微机械惯性传感器检测平台的设计与应用

一种用于微机械惯性传感器研制与开发的检测平台,介绍电容式惯性传感器微电容信号的检测原理、该系统的总体结构、各个组成部分的工作原理及自动检测方法。     

舵机自动测试系统的设计与实现

为更灵活准确的测试舵机性能和寿命,研制了基于工控机、力矩加载器、力矩传感器、角度传感器的舵机性能和寿命自动测试系统。测试系统采用NI公司生产的便携式一体化PXI机箱和高精度多功能采集卡,在测试过程中实时监测采集舵机控制器的电压电流和舵机位置信号;采用Lab VIEW编程平台开发了相应的测试软件,设计了友好的人机交互界面,实现了舵机产品的参数测量及合格性判断。通过实验比对新旧测试系统对同一舵机产品测试数据,证明新测试系统测试精度和测试效率都更高。     

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。     

Metallic microgripper with SU-8 adaptor as end-effectors for heterogeneous micro/nano assembly applications

This paper presents design, fabrication, and characterization of easy-to-handle electroplated nickel microgrippers with SU-8 adaptors for heterogeneous micro/nano assembly applications. Two distinctive designs of microgrippers as end-effectors of micro/nano assembly applications have been developed in this work. The first design is 200 m thick electroplated nickel microgripper with a plastic mechanical displacement amplifier that is driven by a piezoelectric actuator. The piezoelectric actuator is capable of creating 5 m displacement which is amplified to 10 m by the plastic mechanical amplifier and finally such displacement generates 50–139 m microgripper tip displacement. The second design is 20 m thick electroplated nickel microgripper embedded in SU-8 adaptor for easy-to-handle operation. The second design is electro-thermally actuated using a set of joule-heated bent beams. With applied actuation voltage in the range of 2–4 V, the microgripper generates tip displacement of 4–32 m. Extensive thermal and mechanical finite element modeling have been carried out and measurement results were compared with the simulation results. Such developed easy-to-handle microgrippers can be used for micro/nano pick-and-place assembly applications.This work was supported by the National Institute of Standards and Technology-Advanced Technology Program (NIST-ATP 70NANB1H3021). The authors would like to thank the members of Design Engineering Group at Zyvex Corporation, Mr. Yohannes Desta from the Center for Advanced Microstructures and Devices (CAMD) at Louisiana State University for the valuable technical discussions, and the members of Micro and Nano Device and Systems (MiNDS) Laboratory and Cleanroom staffs at the University of Texas at Dallas.     

A RBF neural network sliding mode controller for SMA actuator

A radial basis function neural network sliding-mode controller (RBFSMC) is proposed to control a shape memory alloy (SMA) actuator. This approach, which combines a RBF neural network with sliding-mode control (SMC), is presented for the tracking control of a class of nonlinear systems having parameter uncertainties. The centers and output weights of the RBF neural network are updated through on-line learning, which causes the output of the neural network control to approximate the sliding-mode equivalent control along the direction that makes the sliding-mode asymptotically stable. Using Lyapunov theory, the asymptotic stability of the overall system is proven. Then, the controller is applied to compensate for the hysteresis phenomenon seen in SMA. The results show that the controller was applied successfully. The control results are also compared to those of a conventional SMC.     

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.     

The design and simulation of a novel out-of-plane micro electrostatic actuator

This paper presents a mechanism of developing a novel out-of-plane micro electrostatic actuator capable of causing large out-of-plane deflection. The performance of the actuator is evaluated and simulated by MEMCAD software. Initial analysis results indicated that the usage of both the novel U-shape suspension beam and the electrostatic actuation mechanism permit large rotations motion with respect to the increment of the numbers of electrodes. Moreover, stable rotational motion can be achieved by varying the dimensions of electrode and gap spacing. This design advantage brings the possibility of developing other three-dimensional (3D) structures for on and/or out-of-wafer applications such as optical switch or display.