新型电致活化材料—介电弹性体的驱动特性研究

为解决微型致动器、人造肌肉、仿生机器人等新型科技研究领域短缺问题,将电活性聚合物材料—介电弹性体应用于新型驱动器研究中,开展了对弹性体材料驱动特性的相关分析.通过实验研究了影响E-ACE材料激活区(电极涂层区域)面积应变的主要因素,以寻找激活区面积应变和这些影响因素之间的关系,进而根据它们之间的关系确定能获得所需激活区...     

介电弹性体线性驱动器研究

为满足未来机电系统对新型驱动器的需求,研究菱形介电弹性体线性驱动器。在分析驱动器工作原理的基础上,通过驱动器力—位移曲线和预载荷关系的分析,确定弹性预载荷元件。驱动器通电后能迅速响应,线性位移达到21 mm,弹性体面积变化率达到98%;驱动器失电后能迅速退回,最终退回到初始位置。通过试验分析电压和负载对驱动器的影响,试验表明：驱动器输出位移取决于电压;负载在驱动器输出力范围内对输出位移影响不大,但会影响其运动速度。并根据驱动器的特点,指出驱动器的应用范围。     

介电弹性体发电机机电转换的非线性方法研究

针对介电弹性体(DEG)研究中存在的效率瓶颈问题,对DEG机电能量转换方法进行了研究,提出了一种非线性DEG机电能量转换方法,并通过分析其基本机理,建立了非线性方法的理论模型和Matlab/Simulink仿真模型,对负载电阻值及翻转品质因子对机电转换效率的影响进行仿真。通过优化材料、机械传动结构、电路各元件参数配置及开关通断时间,提高了翻转品质因子Q,减少了电容电感串联形成电压翻转而造成的能量损失,进一步提高了机电效率。研究结果表明,通过对标准机电转换方法和非线性机电转换方法的比较,由于非线性转换环节的作用,使DEG两端电压的振幅大幅度提升,沿电压轴方向扩展了能量环,从而使DEG机电转换效率提高2.5倍;该研究结果对DEG的深入研究具有重要的意义。     

锥型介电弹性体驱动器的性能研究

介电弹性体驱动器在机器人系统、医疗机械系统以及智能驱动系统方面已经显示出广泛的应用潜能,具有结构简单、质量轻、能量密度大、效率高、变形大的优点.采用3M VHB4910介电弹性体设计并制作了锥型介电弹性体驱动器,并进行了锥型驱动器的驱动实验.测得锥型驱动器在一个通断电过程中的力一位移曲线,并计算得到驱动器的差力为1.65 N.实验结果表明锥型驱动器在通电后可以较大的线性位移,面积变化率为15.49%,断电后又能较快地恢复初始位置.同时对驱动器在一个工作周期中的做功进行分析,指出锥型驱动器可以通过多层薄膜的叠加来提高输出功.     

介电弹性体无阀微泵设计

无阀微泵原理新颖,但压电式无阀微泵工艺复杂。介电弹性体是具有大变形的智能材料,采用图像处理的方法对其变形特性做了测试,并利用其特殊性能研制了介电弹性体无阀微泵。从流道设计、尺寸、流量和效率3个方面研究了介电弹性体无阀微泵,得到流量为142.12 m L/min,效率为0.738的介电弹性体无阀微泵。其特点是原理新颖、结构简单、流量和效率理想。     

基于介电弹性体的旋转步进柔性驱动器

为了适应未来小型自动化机器的驱动需求,设计并实现了一种基于单层介电弹性体薄膜的旋转步进柔性驱动器。相对于传统双轴拉伸装置,自制的八爪拉伸装置使介电弹性体薄膜的预拉伸更均匀。测试了不同预拉伸量下介电弹性体驱动器的最大形变量,确定了制作驱动单元所需的介电弹性体薄膜最佳的预拉伸量。最终通过合理的设计将棘轮机构和驱动单元相结合实现了旋转步进柔性驱动。由于介电弹性体驱动器存在迟滞现象,导致驱动器的步进频率会随着负载质量的增大而减小。通过调节驱动信号的频率,可以改变驱动器的负载能力及步进频率。试验结果表明,当驱动电压为4.53 kV,空载时驱动器步进频率最高可达2.3 Hz;负载时,最大负载为263 g,即峰值扭矩为13.15 mN·m,此时步进频率降至0.22 Hz。     

介电弹性体摆动驱动器的分析与实现

根据介电弹性体摆动驱动器的工作原理,设计了摆动驱动器.通过对比试验得到性能较佳的摆动驱动器,该摆动驱动器的研究可为仿生机器人的驱动实现提供一种可能的解决方案.     

介电弹性体机电性能测试系统的研制

为了能更安全高效地测试介电弹性体的变形和应变,建立了一种介电弹性体机电性能测试系统。首先设计双向材料预拉伸机构,实现对介电弹性体薄膜进行精确的双向预拉伸,接着使用AVR单片机编写的PWM程序给介电弹性体中心的圆形电极区域逐步施加高电压,再使用高性能工业数字摄像机对介电弹性体薄膜的变化进行实时采集。最后用MATLAB编写的程序分别打开各次采集的图像,对所采集图像进行诸如灰度图、二值化、边缘提取、形态学处理等加工,获得介电弹性体中心的圆形电极区域图像面积的变化量,从而得到介电弹性体的机电特性曲线。     

A tubular dielectric elastomer actuator: Fabrication, characterization and active vibration isolation

This contribution reviews the fabrication, characterization and active vibration isolation performance of a core-free rolled tubular dielectric elastomer (DE) actuator, which has been designed and developed by Danfoss PolyPower A/S. PolyPower DE material, PolyPower^TM, is produced in thin sheets of 80 μm thickness with corrugated metallic electrodes on both sides. Tubular actuators are manufactured by rolling the DE sheets in a cylindrical shape. The electromechanical characteristics of such actuators are modeled based on equilibrium pressure equation. The model is validated with experimental measurements from 3 actuators. The dynamic characteristics of three tubular actuators fabricated from the same batch of manufactured DE material are presented and compared to: (a) provide insight into the ability of the fabrication process to produce actuators with similar characteristics and (b) highlight the dominant dynamic characteristics of the core-free tubular actuator. It has been observed that all actuators have similar dynamic characteristics in a frequency range up to 1 kHz. A tubular actuator is then used to provide active vibration isolation (AVI) of a 250 g mass subject to shaker generated ‘ground vibration’. An adaptive feedforward control approach is used to achieve this. The tubular actuator is shown to provide excellent isolation against harmonic vibratory disturbances with attenuation of the resulting 5 and 10 Hz harmonics being 66 and 23 dB, respectively. AVI against a narrow band vibratory disturbance with frequency content 2–8 Hz, produced an attenuation of 20 dB across the frequency band.     

以介电常数为中心的自动土壤水分观测设备标定体系的探讨

文章探讨了根据FDR（频域反射法）原理进行观测的自动土壤水分观测设备的标定过程。目前投入使用的自动土壤水分观测设备,存在着重新标定困难和设备标定周期长、标定环节多、标定误差较大、人工工作量大等问题,为了改善这些问题,以提高设备标定精度和标定效率、减少人工重复性劳动,建立以介电常数为中心的标定体系模型,该体系可对标定过程中产生误差的各个环节和仪器观测数据在标定中的使用进行分析。     

Determination of the composition of biodiesel-diesel blends using the dielectric constant

There are many methods used to measure the composition of biodiesel in diesel. However, standard methods are limited by high cost and limited precision. Here is proposed a low-cost sensor to determine biodiesel in binary blends of biodiesel/diesel, using the dielectric constant. The concentrations were varied from 0–9% at frequencies from 100–2000 Hz. The correlation curves between the dielectric constant and the biodiesel/diesel concentration included an adjustment factor of 0.992. Moreover, the values of the dielectric constant obtained for each blend were statistically distinct, yielding precise measurements.     

Control of the dielectric microrods rotation in liquid by alternating current electric field

Microfluidics is a promising system for the manipulation of micro-nano particles and fluids. In this platform, alternating current （AC） electric field is usual an effective tool for the general particles control. However, traditional work paid more attention on the regular spherical particles with no obvious distinction when rotating, resulting in imprecise rotation speed calculation. In essence, non-spherical especially biocompatible particles are not only important for biology application but also significant for obtaining accurate rotating results. Hence, in this paper, SU-8, one of the most biocompatible materials was selected as the manipulation object. AC electric field is employed to rotate SU-8 microrods, in order to obtain a controllable rotation angle for both the accurate experimental results and biosensor applications. Firstly, Clausius-Mossotti（CM） factors frequency spectra with different surface conductance and medium conductivities are presented, thereby the theoretical formula is carried out, including both the torque and rotation velocity expressions of SU-8 microrods. Moreover, simulations for the electric field distribution are developed, indicating the rotating direction. Secondly, the quadrupole electrodes are used to generate rotating electric field, and the electrorotation of SU-8 microrods in different medium is carried out, showing that the particles rotate in the opposite direction of the electric field, meanwhile, the peak frequency increases with the conductivity increases. Finally, the experimental results are discussed and compared with theoretical analysis, and the comparison result shows that they have a good agreement. This work proposes an effective and controllable method to rotate microrods, showing extend application potentials in microelectronics and biosensors.     

Performance Investigation of Cone Dielectric Elastomer Actuator Using Taguchi Method

Dielectric elastomer actuator (DEA) show promise for mechatronic applications due to the advantages of dielectric elastomer, such as lightweight, flexible, low cost, high strain, etc, and many configurations of DEAs have been demonstrated. As a kind of linear actuator, cone DEAs are studied in some laboratory prototypes due to easy manufacturing, however, their performance have not been exploited fully. Based on the working principle of DEA, a four-bar linkage mechanism is designed to provide negative stiffness preload, which can increase displacement output of actuator (outer diameter 100 mm) to 17 mm. Three cone actuating units are assembled in parallel to enhance the maximum force output to 5.07 N. Loading experiments of actuator in forward and backward strokes are performed, the experimental results show that backward stroke has stronger actuating capability than forward stroke, accordingly application of actuator is recommended. Four factors rather than applied voltage, i.e., number of actuating units, pre-stretch ratio, inner diameter, and outer diameter, are determined as influencing factors for Taguchi method. Then the performance objectives of actuator, i.e., displacement output, maximum force output, and maximum work in backward stroke, are investigated based on L9(34) Taguchi orthogonal design. The mean signal-to-noise (S/N) ratio based on the larger-the-better criterion is calculated according to the acquired displacement and force output. Analytical results show that outer diameter has the most significant influence on displacement output, and maximum force out and work output are influenced most by number of actuating units. Inner diameter also has an important effect on the performance objectives of actuator, while pre-stretch ratio has the least influence. The proposed performance investigation is helpful for the design and application of cone actuator in mechatronic system.     

全息方法制备嵌段式液晶弹性体

研究了热致收缩形变三嵌段式液晶(LC)弹性体薄膜的制备方法,分析和测试了薄膜的偏光特性和热致收缩率.采用全息曝光的方法一次性制备出具有栅状结构的热致液晶弹性体薄膜材料.在此基础上采用偏光显微镜(POM)、He-Ne激光器对弹性体薄膜的嵌段式栅状结构和偏光特性进行检测,并分析了薄膜弹性体偏光特性和液晶分子取向的关系,对该...     

用C方法计算介质膜光栅衍射效率

运用C方法对介质膜基底反射光栅的衍射效率进行了详细的理论分析。在此基础上用正弦函数的高次幂作为光栅的槽形函数编写了介质膜光栅衍射效率计算程序,数值计算结果表明了C方法在计算介质膜光栅衍射效率的可行性。     

微波陶瓷介质谐振器优选组合检测法

微波介质陶瓷材料的介电性能主要由3个参数表示:介电常数、介质损耗和谐振频率温度系数.本文优选组合了3种检测介质谐振器方法:短路型介质谐振器轴向的短路界面测定方便准确,用于测量微波介质陶瓷材料的相对介电常数;开路型平行板与介质谐振器无直接接触,用于测量介质损耗系数;自行研制的旋转开放腔,可同时放置多个样品,加快温度系数的测量速度.3个参数采用3种不同测试法,充分应用了不同测试法各自的优势,满足微波介质陶瓷材料介电常数跨度大、介质损耗低、温度系数快速测量的需求,可得到精确、快速的测试效果.