磁能驱动微型泵的性能实验研究

在电磁场驱动原理的基础上,设计并研制了一种磁能驱动的微型泵。微型泵包括进／出液管、扩散管／喷管、驱动薄膜、腔体、电磁线圈和永磁体。微型泵的整体尺寸约为Ф11mm×4mm,腔室半径为5mm,深2mm。利用正交实验方法,对微型泵的性能进行了测试。在电压为4V、驱动薄膜厚度为6μm、频率为5Hz方波脉冲的最佳实验条件下,微型泵的最大泵送流速约为0．21mL／min。     

微型轴流式血泵外磁驱动电路设计

微型轴流式血泵是目前人工心脏结构研究的热点．外磁驱动是一种新型的血泵驱动方式。本文介绍了血泵外磁驱动电路的设计。该电路能够产生双向励磁电流．直接驱动电机，实现血泵的外磁驱动。电路简单、实用，稳定性较好。     

微流道交流电水力泵的数值模拟及优化

描述了微通道内交流电水力泵(EHD)的工作原理,并用IntelliSuite(R)的Microfluidic模块对电水力泵进行数值模拟.并分析了影响电水力泵速度场分布的因素,包括流体电导率、驱动交流电频率和相位、电极维度以及电极间隙和数量等.通过数值模拟不同参数下的电水力泵,比较驱动压力大小,最后给出优化的设计结果,为给电水力泵设计参数的选择提供依据.本文对流道长度为5mm,宽0.4mm,厚度0.4mm的电水力泵做了优化设计的数值模拟,最后得到驱动电极宽度为0.01mm,电极间距为0.02mm.     

一种用于微型工厂的毫米级全方位移动微机器人设计与分析

介绍了一种毫米级全方位移动微机器人,尺寸为9mm*8mm*8mm。独特的双轮设计实现了转向时与地面的滚动摩擦。驱动器为3个直径2mm的电磁微马达,其中2个用于直线驱动,另一个用于转向。运动受力分析揭示了微马达驱动力矩与双轮结构尺寸及各种摩擦之间的关系。仿真计算及实验表明微机器人具有良好的负载能力,能够满足微型工厂中的搬运操作要求。     

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．     

磁力驱动微泵设计及优化

为提高收缩/扩散管无阀微泵的性能,设计了磁力驱动式无阀微泵,并利用ANSYS软件对微泵的整流部件收缩/扩散管和单腔微泵整体结构进行流体仿真,得到了微泵的结构优化参数.仿真和实验结果表明,流量随着管长、最小宽度、扩张角、泵腔半径的增大存在极大值.磁驱动微泵的流量在驱动电压12 V、驱动频率为25 Hz时达到最大值.     

基于旋转谐振结构的单芯片二维电场传感器

提出并研制了一种二维电场检测传感芯片,将四个电场测量微型单元和旋转式驱动微结构集成在3. 5 mm ×3. 5 mm的敏感结构上,实现了单芯片的电场二维测量.介绍了传感器的工作原理、敏感结构的设计,以及基于绝缘体上硅( SOI)工艺的单芯片微型二维电场传感器制备工艺技术.成功研制出传感器原理样机,研究了微型二维电场传感器的标定方法,开发了用于电场二维标定的测试装置,并在室温常压下对传感器进行了二维标定.实验结果表明:该传感器能够有效减小电场的轴间耦合干扰,测量误差优于7. 04%,线性度可达到1. 25%.     

微型仿生四足机器人的研究

介绍了一种微型仿生四足机器人,对其机械结构和运动方式进行了理论分析和软件仿真,并制作了机器人样机,其长度41 mm,宽度49 mm,高度29 mm.利用两套平面连杆机构的有效组合,模拟了足式运动的抬腿、前跨、后拉等动作,通过可旋转式的机身实现机器人的转向,以微型电机配合微型齿轮减速器作为机器人驱动源.     

微型仿生肠道内窥镜机器人的设计与实验

根据当前胃肠道内窥镜自主运动机器人的研究方向,设计了一种微型的肠道内窥镜机器人系统。机器人采用仿尺蠖式的运动步态,通过直流无刷电机驱动驻留-伸缩-驻留式的结构实现主动运动。整体采用模块化设计,主要包括驻留机构、伸缩机构、电路控制系统以及无线供能模块。对机器人结构模型进行了理论探讨,介绍了电路控制系统的设计,以及无线供能模块的构成。最终的机器人样机直径约为14 mm,整体长度约为61 mm。机器人在PVC柔性管道和猪小肠离体爬行实验中运行稳定可靠,能够实现前进、退后和停留等步态。实验结果表明该微型仿生肠道内窥镜机器人在肠道内可以实现主动运动。     

六足微型仿生机器人及其控制系统的研究

介绍了一种微型六足仿生机器人的结构与控制系统，分析了这种微型六足仿生机器人的移动原理，阐述了如何通过计算机来控制微型六足仿生机器人的运动，该机器人基于仿生学原理，结构独特，简单，新颖，能方便地实现前进和后退，其样相外形尺寸为：长30mm,宽40mm,高20mm，重6．3克，并对该样机进行了实验，实验结果表明该机器人具有较好的机动性。     

Characteristic studies of the piezoelectrically actuated micropump with check valve

This study presents the design and fabrication of a novel piezoelectric actuator for a micropump with check valve having the advantages of miniature size, light weight and low power consumption. The micropump is designed to have five major components, namely a piezoelectric actuator, a stainless steel chamber layer with membrane, two stainless steel channel layers with two valve seats, and a nickel check valve layer with two bridge-type check valves. A prototype of the micropump, with a size of 10 × 10 × 1.0 mm, is fabricated by precise manufacturing. The check valve layer was fabricated by nickel electroforming process on a stainless steel substrate. The chamber and the channel layer were made of the stainless steel manufactured using the lithography and etching process based on MEMS fabrication technology. The experimental results demonstrate that the flow rate of micropump accurately controlled by regulating the operating frequency and voltage. The flow rate of 1.82 ml/min and back pressure of 32 kPa are obtained when the micropump is driven with alternating sine-wave voltage of 120 Vpp at 160 Hz. The micropump proposed in this study provides a valuable contribution to the ongoing development of microfluidic systems.     

Piezoelectrically actuated dome-shaped diaphragm micropump

This paper describes a piezoelectric micropump built on a dome-shaped diaphragm with one-way parylene valves. The micropump uses piezoelectric ZnO film (less than 10 /spl mu/m thick) to actuate a parylene dome diaphragm, which is fabricated with an innovative, IC-compatible process on a silicon substrate. Piezoelectric ZnO film is sputter-deposited on a parylene dome diaphragm with its C-axis oriented perpendicular to the dome surface. Two one-way check valves (made of parylene) are integrated with a piezoelectrically actuated dome diaphragm to form a multi-chip micropump. The fabricated micropump (10/spl times/10/spl times/1.6 mm/sup 3/) consumes extremely low power (i.e., 3 mW to pump 3.2 /spl mu/L/min) and shows negligible leak up to 700 Pa static differential pressure.     

Development of an Electrohydrodynamic Injection Micropump and Its Potential Application in Pumping Fluids in Cryogenic Cooling Systems

Cryogenic cooling has become a widely adopted technique to improve the performance of electronics and sensors. A potential application of an electrohydrodynamic (EHD) pumping system is its use in pumping fluids in cryogenic cooling systems. In this paper, we present the results of a theoretical/experimental investigation to study the feasibility of using an EHD injection micropump for pumping liquid nitrogen. First, the mechanisms of charge transport and ionization phenomenon in cryogenic liquids are discussed. Next, the design and fabrication of an EHD injection micropump that employs an array of interdigitated saw-tooth/plane electrodes are described. Finally, experimental results and observations are presented. An asymmetric saw-tooth/plane geometry was designed to achieve a strong inhomogeneous electric field. Each emitter electrode had a base width of 10$mu$m. Each tooth on the emitter electrode had a base length of 10$mu$m with a tip angle of 60$^circ$. The collector electrode consisted of a planar strip with a width of 10$mu$m. The gap between emitter and collector electrodes was 20$mu$m. The distance between each neighboring stage (a pair of emitter and collector electrodes) was 40$mu$m. The patterned area was 10 mm by 20 mm allowing approximately 200 stages to be fabricated along the length of the micropump. The maximum pressure head achieved by this micropump in the absence of a net flow was 550 and 205 Pa for 3M's HFE-7100 thermal fluid and liquid nitrogen, respectively. Also, the maximum mass flow rate was 3.9 g/min at the generated pressure of 180 Pa during a closed loop test with HFE-7100.hfillhbox[1063]     

An Electrolysis-Bubble-Actuated Micropump Based on the Roughness Gradient Design of Hydrophobic Surface

A novel electrolysis-bubble-actuated micropump based on the roughness gradient design in the microchannel is reported in this paper. This micropump is implemented by taking advantage of both the electrolysis actuation and the surface tension effect. The surface tension effect is controlled via the periodic generation of electrolytic bubbles and the roughness gradient design of microchannel surface, which results in the specified variation of liquid contact angle along the microchannel. Our proposed micropump could resolve the disadvantages that exist in the early reported micropumps, such as the complicated time-sequence power control, the need of long nozzle-diffuser structure, and the choking/sticking phenomena of electrolytic bubbles in a microchannel. Due to the features of large actuation force, low-power consumption, and room temperature operation, our micropump is suitable for the development of low-power consumption and compact micropumps for various applications. Experimental results show that the liquid displacement and the pumping rate could be easily and accurately controlled by adjusting the amplitude and frequency of the applied voltage. With the applied voltage of 15 V at 4.5 Hz, a maximum pumping rate of 114 nl/min is achieved for one of our micropump designs with a microchannel of 100 x 20 mum. In this paper, we report the theoretical analysis, design, micromachining process, operating principles, characterization, and experimental demonstration of these micropumps.     

Study on a piezoelectric micropump for the controlled drug delivery system

We present the design of a new controlled drug delivery system potential for in vitro injection of diabetics. The system incorporates some integrated circuit units and microelectromechanical system devices, such as micropump, microneedle array and microsensor. Its goal is to achieve safer and more effective drug delivery. Moreover, a valveless micropump excited by the piezoelectric actuator is designed for the drug delivery system, and a simple fabrication process is proposed. A dynamic model is developed for the valveless micropump based upon the mass conservation. To characterize the micropump, a complete electro-solid-fluid coupling model, including the diffuser/nozzle element and the piezoelectric actuator, is built using the ANSYS software. The simulation results show that the performance of micropump is in direct proportion to the stroke volume of the pump membrane and there is an optimal thickness of the piezoelectric membrane under the 500 V/mm electric field. Based on this simulation model, the effects of several important parameters such as excitation voltage, excitation frequency, pump membrane dimension, piezoelectric membrane dimension and mechanical properties on the characteristics of valveless micropump have been investigated.     

Numerical analysis of non Newtonian fluid flow in a low voltage cascade electroosmotic micropump

In microfluidic devices, many fluids have non-Newtonian behaviors, especially biofluids. The viscosity of these fluids mostly depends on the shear rate. Sometimes the non-Newtonian fluids should be transferred by micropumps in lab-on-chip devices. Previous researchers investigated the flow rate in simple electroosmotic flow micropumps which have a simple channel geometry. In the present study, the effects of non-Newtonian properties of fluid in a low voltage cascade electroosmotic micropump are numerically investigated using the power law model. The micropump is modeled in two dimensional with one symmetric step and has a more complex geometry than previous studies. The numerical results show that, the non-Newtonian behavior of fluid affects flow rate in the micropump. The flow rate decreases if the fluid is dilatant. Also, it increases if the fluid is pseudoplastic. Moreover, the pressure which is needed to stop the electroosmotic flow rate in the micropump is calculated. Results show that, the back pressure has a slight change as the fluid has non-Newtonian behavior.     

A high flow rate thermal bubble-driven micropump with induction heating

A thermal bubble-driven micropump with magnetic induction heating is successfully demonstrated in this paper. Energy is transferred from the planar coil outside the microchamber to the metal heating plate inside the microchamber through the electromagnetic field, and Joule heat is induced by the eddy current in the heating plate. Sequential photographs of bubble nucleation, growth and shrink in open environment were recorded by a CCD camera. One advantage of the micropump is that there is no physical contact between the heating plate and the external power supply circuit, which resulted in an easy fabrication process. What’s more, compared with other thermal bubble-driven micropump with resistive microheater, the flow rate and the pump stroke have been improved significantly due to its larger dimension of the heating plate and larger bubbles volume. The experiments show that the maximum flow rate of this micropump is about 102.05 μL/min, which can expand the potential applications, especially for microfluidic system that requires higher flow rate.     

Magnetic active-valve micropump actuated by a rotating magnetic assembly

We report on a high-efficiency and self-priming active-valve micropump consisting of a microfluidic chamber structure in glass that is assembled with a polydimethylsiloxane (PDMS) elastic sheet. The latter comprises two valving membranes and a central pumping chamber actuation membrane, having each an integrated permanent magnet that is magnetically actuated by arc-shaped NdFeB permanent magnets mounted on the rotation axis of a DC minimotor. The choice of this actuation principle allows very low-voltage (0.7 V) and low power (a few 10 mW) operation of the micropump. For the realisation, we use affordable powder blasting glass micropatterning and PDMS molding technologies. A flow rate of 2.4 mL/min and up to 70 mbar backpressure are obtained at the micropump resonance frequency of around 12 Hz, values that are much higher than reported so far for such type of micropump.     

A surface-tension driven micropump for low-voltage and low-power operations

In this paper, we first report a micropump actuated by surface tension based on continuous electrowetting (CEW). We have used the surface-tension-induced motion of a mercury drop in a microchannel filled with an electrolyte as actuation energy for the micropump. This allows low voltage operation as well as low-power consumption. The micropump is composed of a stack of three wafers bonded together. The microchannel is formed on a glass wafer using SU-8 and is filled with electrolyte where the mercury drop is inserted. The movement of the mercury pushes or drags the electrolyte, resulting in the deflection of a membrane that is formed on the second silicon wafer. Another silicon wafer, which has passive check valves and holes, is stacked on the membrane wafer, forming inlet and outlet chambers. Finally, these two chambers are connected through a silicone tube forming the complete micropump. The performance of the fabricated micropump has been tested for various operation voltages and frequencies. We have demonstrated actual liquid pumping up to 70 /spl mu/l/min with a driving voltage of 2.3 V and a power consumption of 170 /spl mu/W. The maximum pump pressure is about 800 Pa at the applied voltage of 2.3 V with an operation frequency of 25 Hz.