电场活化聚合物卷筒型致动器设计方法研究

通过研究电场活化聚合物(dielectric elastomer,DE)卷筒型致动器的工作原理,分别构建出一维伸缩驱动器、平面弯曲驱动器和平面转角驱动器的力学模型,并提出其设计方法。数值模拟的结果表明,所设计的卷筒型致动器可以实现预期的伸缩、平面弯曲和平面转动等运动,从而为该类微致动器的进一步设计研究和应用奠定基础。     

基于电场活化聚合物的一维伸缩致动器设计

电场活化聚合物一维伸缩致动器是一种能够将电能直接转化为直线运动的装置,可应用于机器人等方面.文中以HN-1110T型DE材料的Ogden本构模型为基础,以卷筒型一维伸缩致动器为设计对象,探索可靠的电场活化聚合物一维伸缩致动器设计方法.     

基于弹性体材料仿生手的设计、制造及其控制

软体机器人是近年来的研究热点,涉及信号检测、控制、致动等多个方面。基于弹性体材料设计制备了一种符合人体手指运动规律的弯曲致动器及其仿生手和电容式可拉伸传感器。仿生手总共设计有14个弯曲关节,且每个弯曲关节都由外部管道独立控制,当外部气压达到50 k Pa时,手指关节能够实现90o的弯曲变形,最大指尖压力为210m N。可拉伸应变传感器在200%应变下表现出良好的稳定性和可逆性,将传感器贴在手指关节上具有监测手指运动的功能。最后,将传感器贴于手套上作为可穿戴器件,通过单片机控制系统采集手套上传感器由于手指弯曲产生的信号,信号经蓝牙传输,实现对气动回路的有效控制,最终完成对仿生手的远程实时操控。研究结果可应用于远程交互、生命科学等领域。     

软体机械手遥操作系统的设计与分析

面向气动软体机械手在远程非结构化环境下作业的工作需求,搭建了软体机械手遥操作系统。基于“快速气动网络”及模块化可拆卸原则,设计制作了软体弯曲致动器,根据实验需要组装成仿人手形软体机械手。在Yeoh模型基础上建立了软体致动器的力学模型并借助仿真分析加以修正,为软体致动器的控制提供了理论依据。设计了遥操作系统的总体结构,提出了气动软体机械手的驱动模式与控制策略,在C#窗体应用程序中开发了客户端软件。基于蒙皮技术在3D Max软件中对软体致动器进行建模,在Unity3D中搭建了虚拟作业场景,通过脚本程序设计实现远地端反馈信息对软体末端的运动控制和对目标对象的碰撞与拾取。开展软体致动器弯曲角度与充气气压实验,验证分析力学模型的准确性;开展遥操作手势映射实验,分析与探讨软体机械手遥操作系统的可行性及其进一步研究与应用。     

一种调频式共振消声器的设计

采用微机电系统(micro electrical mechanism system,简称MEMS)工艺制作了一种气泡致动器,该致动器结构可整体弯曲变形,适于安装在消声器内部.通过调节致动器驱动压力的大小,控制气泡的变形高度,导致消声器的共振腔体积发生变化,实现对多个频率噪声的抑制.试验表明,当致动器的驱动压力分别为0.04和0.07 MPa时,消声器的共振频率由745 Hz变化为736和731 Hz,所设计的消声器实现了对多个频率噪声的抑制作用.     

电场活化聚合物驱动器动态机电耦合特性研究

通过分析电场活化聚合物材料的力学行为理论,建立了基于常见应变能函数（Mooney-Rivlin模型、Ogden模型和Yeoh模型）的电场活化聚合物驱动器的机电耦合本构模型。通过驱动实验,将3种机电耦合模型结果与实验数据进行了对比分析,得出影响电场活化聚合物机电稳定性的重要因素,确定了最适用于电场活化聚合物的机电耦合性能行为的模型。     

压电智能梁的拉伸-弯曲耦合模型

利用虚功原理,建立了单面粘贴有压电致动器的梁结构的拉伸－弯曲耦合模型,在分析过程中,考虑了梁与致动器之间粘贴层的影响。通过分析可得,粘贴层剪切应力的分布与致动器端部附近的应变分布有相似的特征。随着粘贴层的剪切模量的增加或其厚度的减小,则剪切力在靠近压电致动器端部区域迅速增大。     

压电智能梁的拉伸—弯曲耦合模型

利用力平衡原理,建立了单面粘贴有压电致动器的梁结构的拉伸—弯曲耦合模型,在分析过程中,考虑了梁与致动器之间粘贴层的影响。通过分析可得,粘贴层切应力的分布与致动器端部附近的应变分布有相似的特征,随着粘贴层的切变模量的增加或其厚度的减小,切应力在靠近压电致动器端部区域迅速增大。     

压电智能梁的静态耦合模型

利用力平衡原理，建立了单面粘贴有压电致动器的梁结构的静态拉伸－弯曲耦合模型，在分析过程中，考虑了梁与致动器之间粘贴层的影响。通过分析可得，粘贴层剪切应力的分布与致动器端部附近的应变分布有相似的特征。随着粘贴层的剪切模量的增加或其厚度的减小，剪切力在靠近压电致动器端部区域迅速增大。     

压电智能梁的静态耦合模型

利用力平衡原理，建立了单面粘贴有压电致动器的梁结构的静态拉伸－弯曲耦合模型，在分析过程中，考虑了梁与致动器之间粘贴层的影响。通过分析可得，粘贴层剪切应力的分布与致动器中附近的应变分布有相似的特征。随着粘贴层的剪切模量的增加或其厚度的减小，剪切力在靠近坟电致动器部分端部区域迅速增大。     

A face robot actuated with artificial muscle based on dielectric elastomer

Face robots capable of expressing their emotional status, can be adopted as an efficient tool for friendly communication between the human and the machine In this paper, we present a face robot actuated with artificial muscle based on dielectric elastomer By exploiting the properties of dielectric elastomer, it is possible to actuate the covering skin, eyes as well as provide human-like expressivity without employing complicated mechanisms The robot is driven by seven actuator modules such eye, eyebrow, eyelid, brow, cheek, jaw and neck module corresponding to movements of facial muscles Although they are only part of the whole set of facial motions, our approach is sufficient to generate six fundamental facial expressions such as surprise, fear, angry, disgust, sadness, and happiness In the robot, each module communicates with the others via CAN communication protocol and according to the desired emotional expressions, the facial motions are generated by combining the motions of each actuator module A prototype of the robot has been developed and several experiments have been conducted to validate its feasibility     

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.     

介电型电活性聚合物圆柱形驱动器的驱动效率

研究了介电型电活性聚合物(DEAP)驱动器的机电能量转换机理、能量损耗和驱动效率。建立了驱动器机电能量转换模型,并通过试验测算了驱动器等效电路的模型参数,分析了电极材料等因素对DEAP相对介电常数的影响。深入研究了驱动器漏电流损耗,试验验证了漏电流对驱动器性能的影响。最后,设计了驱动器驱动试验台,完成了不同行程的准静态驱动试验,数值计算了驱动器的驱动效率。结果表明:由于等效电路电容未参与能量转换,驱动器机电转换效率分别为17.6%和25.6%。低电压、小行程驱动时,试验误差与理论分析误差不超过15%;而高电压、大行程驱动时,DEAP膜的漏电流等非线性因素使其驱动效率变化明显。该结果可为DEAP圆柱形驱动器的优化设计及合理使用提供指导。     

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。     

压电旋转驱动器制作及性能测试

提出了通过控制正压力来改变摩擦力的方案,进而研制了一种以压电叠堆为动力转换元件的新型压电旋转驱动器。采用两个驱动用压电叠堆对称布置的方式设计了该旋转驱动器结构,探讨了旋转驱动器运动机理,制作了压电旋转驱动器试验样机并对其进行了试验测试。试验结果表明,该驱动器输出步长线性度较好,当驱动电压为10 V、频率为2 Hz时,驱动器旋转步长为20 μrad。分析了驱动器输出稳定性,针对存在的问题提出通过施加控制系统来有效提高不同起始位置驱动器的运动稳定性。对试验结果进行误差分析,找出了产生误差的原因,为驱动器的进一步优化设计提供了参考。研究证明了该压电旋转驱动器设计方法的可行性,利用该方法可以制作出结构简单,体积小,适合在微驱动领域中应用的驱动器。     

Derivation of finite element formulation for electrochemical governing equations of ionic polymer actuators

Ionic polymer actuators have recently attracted a great deal of interest as electroactive materials with potentials as soft actuators, sensors, artificial muscles, robotics, and microelectromechanical systems because of their numerous advantages, including low voltage requirement, high compliance, lightness, and flexibility. The platinum-plated Nafion, a perfluorosulfonic acid membrane made by Dupont, is commonly used as a polyelectrolyte in actuator applications. The bending of the ionic polymer actuators in an electric field is dominated by the electro-osmosis of hydrated ions and slow diffusion of free water molecules. The changes in hydration cause a local volumetric strain resulting in bending deformation, such as expansion and contraction. In this study, a two-dimensional finite element (FE) formulation based on the Galerkin method is derived for the governing equations describing these electrochemical responses. In addition, a three-dimensional FE deformation analysis is conducted on the bending behaviors of the platinum-plated ionic polymer actuators. Several numerical studies for ionic polymer actuators, such as plates with various electrode arrangements and disk models in electric field, are performed to confirm the validity of the proposed formulation.     

Practical and intuitive controller design method for precision positioning of a pneumatic cylinder actuator stage

The present paper describes a practical and intuitive controller design method for precision positioning of pneumatic cylinder actuator stages. Pneumatic actuators are easy to use and have numerous advantages, which has led to these actuators having a wide variety of applications. However, pneumatic actuators have notable nonlinear characteristics, which make precision positioning difficult to achieve. The purpose of the present study is to clarify a practical and intuitive controller design procedure for precision positioning of a pneumatic cylinder actuator. In addition to positioning performance, the present study focuses on the realization of easy controller design without the need for the exact model parameters or knowledge in control theory for general-industrial-use pneumatic cylinder actuators with friction characteristics. These considerations are important in order to fully exploit the advantages of pneumatic cylinder actuators in a wide variety of applications. As such, three elements are added to the conventional continuous-motion nominal characteristic trajectory following (CM NCTF) controller. A new design procedure of the improved CM NCTF controller for pneumatic cylinder actuator stages is introduced, and the positioning performance of the designed control system is examined experimentally under several conditions. The positioning results generally indicate a positioning error of 50 nm, which is equal to the sensor resolution.     

Actuators for the generation of highly nonlinear solitary waves

In this paper we present the design of two actuators for the generation of highly nonlinear solitary waves (HNSWs), which are mechanical waves that can form and travel in highly nonlinear systems. These waves are characterized by a constant spatial wavelength and by a tunable propagation speed, dependent on the wave amplitude. To date, the simplest and widely adopted method to generate HNSWs is by impacting a striker onto a chain of beads of equal size and mass. This operation is conducted manually and it might be impracticable if repetition rates higher than 0.1 Hz are necessary. It is known that the HNSWs' properties, such as amplitude, duration, and speed can be modified by changing the size or the material of the particles, the velocity of the striker, and/or the precompression on the chain. To address the limitations associated with the manual generation of HNSWs we designed, built, and tested two actuators. The first actuator consists of a chain of particles wrapped by an electromagnet that induces static precompression on the chain. This design allows for the generation of solitary waves with controlled properties. The second actuator consists of a chain surmounted by an electromagnet that lifts and releases a striker. This actuator permits the remote and noncontact generation of solitary waves. The performance of both actuators is evaluated by comparing the experimental HNSWs to theoretical predictions, based on the long wavelength approximation.     

Overall life cycle comprehensive assessment of pneumatic and electric actuator

Pneumatic actuators and electric actuators have almost been applied to all manufacturing industries. The two kinds of actuators can replace each other in most fields, such as the point to point transmission occasion and some rotating occasions. However, there are very few research results about the advantages and disadvantages of two kinds of actuators under the same working conditions so far. In this paper, a novel comprehensive assessment method, named as overall life cycle comprehensive assessment （OLCCA）, is proposed for comparison and assessment of pneumatic and electric actuators. OLCCA contains mechanical properties evaluation （MPE）, life cycle cost analysis based on users （LCCABOU） and life cycle environmental impact analysis （LCEIA） algorithm in order to solve three difficult problems： mechanical properties assessment, cost analysis and environmental impact assessment about actuators. The mechanical properties evaluation of actuators is a multi-objective optimization problem. The fuzzy data quantification and information entropy methods are combined to establish MPE algorithm of actuators. Two kinds of pneumatic actuators and electric actuators with similar bearing capacity and similar work stroke were taken for example to verify the correctness of MPE algorithm. The case study of MPE algorithm for actuators verified its correctness. LCCABOU for actuators is also set up. Considering cost complex structure of pneumatic actuators, public device cost even method （PDCEM） is firstly presented to solve cost division of public devices such as compressors, aftercooler, receivers, etc. LCCABOU method is also effective and verified by the three groups of pneumatic actuators and electric actuators. Finally, LCEIA model of actuators is established for the environmental impact assessment of actuators. LCEIA data collection method and model establishment procedure for actuators are also put forward. With Simapro 7, LCEIA comparison results of six actuators can be obtained： Fossil fuels are the major environmental factor of pneumatic and electric actuators; Environmental impact of electric actuator is large than one of pneumatic actuator under the similar mechanical properties and working conditions of pneumatic and electric actuators. The results are correct and correspond with the actual mechanical properties of actuators. This paper proposes a comprehensive evaluation method of the actuators, which can solve the critical problem that similar electromechanical products are very difficult to be compared with each other from the angle of performance, cost and environment impact.