三自由度介电型EAP软材料位置传感器研究

基于介电型电活性聚合物(EAP)变形时的电容值变化原理,设计并实现一种三自由度软材料位置传感器,其内框可沿平面和法向移动,分别用于检测平面和法向位移。建立该传感器的几何模型,推导出其电容值变化和内框位移的关系。采用差分法测试该传感器的电容值变化,分析了面对面两个传感单元的电容值差和内框的平面位移、单个传感单元的电容值和内框的法向位移之间的关系,测试得到其平面和法向位移灵敏度分别为66.69pF/mm、0.47pF/mm~2,与理论分析结果较吻合。该位置传感器的理论与测试分析结果验证了介电型EAP应用于位置传感器中的可行性。     

弯曲型介电型电活性聚合物驱动器的建模研究

介电型电活性聚合物(DEAP)由于其大应变,高效率及高能量密度等优点,在仿生机器人领域具有广泛的应用前景。该文设计制作了一种可实现弯曲变形的DEAP驱动器,根据弹性大变形理论建立驱动器的机电耦合模型,通过微分方程组的迭代求解获得激励电压与输出角度、侧向输出力之间的关系。试验结果表明,在5kV电压下,该驱动器可产生最大75°的弯曲角度,最大侧向输出力达到0.7N。试验结果与理论结果较吻合,验证了驱动器设计与分析的有效性。以该驱动器为驱动单元,构建了一种仿生爬行机器人,初步试验表明了该类型驱动应用于仿生机器人的可行性,可为仿生机器人摆动驱动提供一种新的实现方法。     

EAP换能单元发电量的影响因素分析

电活性聚合物(EAP)作为一种新型电活性软体功能材料,具有多种优点,用于能量收集具有巨大的应用潜力。该文从宏观和微观两个层面阐述了介电材料用于能量收集的机电转化原理,以EAP换能单元为例,说明了EAP换能单元怎样将机械能转化为电能,并阐述了介电弹性体发电机理,为后面EAP换能单元的发电提供理论依据。以其他学者研究得到影响EAP换能单元发电量的因素为基础,通过正交试验得到EAP换能单元发电特性和最佳工作条件,并对试验的可靠性进行了分析。实验结果表明,各因素对EAP材料发电的影响大小顺序为:EAP膜面积>拉伸位移>预加电压>预拉伸率>EAP膜厚度。换能单元最佳工作条件为预加电压1 000 V,预拉伸率400%,拉伸位移4 cm,膜面积62.41 cm~2,EAP膜厚度1 mm。     

精密直线压电驱动器的设计与研究

针对现有直线驱动器精度及输出位移受限等问题,该文基于改进的尺蠖原理,以压电陶瓷堆为动力源设计了一种新型精密直线驱动器。首先介绍该驱动器的结构原理、运行过程及实现方式,然后对该驱动器所用压电陶瓷的特性进行分析,并采用ANSYS对主要部件进行有限元分析。本驱动器采用特有柔性铰链结构和柔性箝位片设计结构,可实现双向移动和输出位移不受限,有效弥补了现有驱动器的一些不足,实用价值较高,有望在微驱动领域推广与应用。     

新型压电扭转驱动器的设计与试验研究

为实现压电扭转驱动器结构的简化,提高能量使用效率,设计了一种新型压电扭转驱动器.使用压电陶瓷双晶片在外加电场下的弯曲位移,通过简单的运动转换机构实现扭转位移的输出.采用激光反射测角法对驱动器输出的微小角度进行了测量,并与有限元仿真结果进行了比较.通过试验证明该方法制作压电扭转驱动器的可行性,并进行了误差分析,为进一步优化设计提供了理论依据.     

基于Si弹性层优化的悬臂梁式微压电驱动器

基于压电材料的逆压电效应,设计并制备了悬臂梁式微压电驱动器,通过电能到机械能的转换,完成装置的位移输出任务。基于悬臂梁式微压电驱动器的设计和仿真,得出该微驱动器Si弹性层的最佳厚度为0.12 mm,仿真结果显示压电层与弹性层厚度比为2~3时,尖端位移输出较大,并模拟了其电压-位移输出情况。采用共晶键合的工艺制备了以PZT-5H为压电层、Au为电极层和Si为弹性层基板并带有Si质量块的微压电驱动器,搭建了直观的激光反射装置作为实验测量系统,测量出在100 V电压条件下,该驱动器的最大输出位移为60μm,最大偏转角为1.948°,在0~100 V初始阶段仿真结果与实验结果具有较高的吻合度,平均相对误差为0.3095。     

电涡流传感器热稳定性标定技术

介绍电涡流传感器位移测量原理,分析温度变化时传感器线圈和探头热胀冷缩在测量位移过程中造成的温度漂移现象.针对传感器的温漂,研制出具有温度补偿功能的电涡流传感器热稳定性标定装置,对传感器输出电压进行温度补偿,减小温度变化对传感器输出电压的影响.同时介绍利用该装置进行温度标定的实现方法,并进行实验验证,实现固定位移条件下环境温度变化时对电涡流传感器输出电压的标定,与无温度补偿时输出电压对比,电压变化量减小了近50%.     

压电式旋转驱动器的设计与实验

为了实现压电驱动器低频率、高效率的输出,设计了一种低频压电式旋转驱动器,这种旋转驱动器结构简单,由低频电源驱动。首先对旋转驱动器进行了结构设计与工作机理分析;然后建立了系统的动力学模型,得出系统输出位移和固有频率表达式;最后制作了实验样机进行实验测试,以微小物料为研究对象,测试驱动器的驱动能力。测试结果表明,当系统频率在91.5Hz时,旋转驱动器性能最佳,输出振动位移大致为45μm,物料移动最大速度为0.15cm/s。     

压电谐波电机承载能力的研究

以保证柔轮与刚轮的正常啮合为条件,引入计算径向变形量系数,设计径向变形量系数以及允许位移损失系数,通过确定位移放大机构输出端允许位移损失量或柔轮的实际径向变形量,计算压电谐波电机承载能力。建立了压电谐波电机承载能力的设计准则,是包括压电驱动器驱动能力选择以及其他结构尺寸设计与校核的主要依据。其输出扭矩与压电驱动器与位移放大机构的刚度成正比,与柔轮变形力、轮齿啮合角以及摩擦系数成反比。克服了基于压电驱动器最大驱动能力建立压电谐波电机输出扭矩方法的缺陷。该模型也可用于采用超磁致伸缩等其他驱动器的谐波电机承载能力的计算。设计计算表明,相对于一般原动机,压电谐波电机能提供较大的输出扭矩。     

基于矩形谐振腔的介电系数测量装置

物质介电系数的测量对微波能的应用十分重要。文中基于谐振腔微扰法设计了一种结构简单的矩形谐振腔测量装置。通过测温孔的设计,该测量装置在测量物质介电系数的同时还能测量待测物的温度,可以得到不同温度条件下物质的介电系数。频率为2.45 GHz时,采用该装置对几种有机溶剂进行测量,得到了与相关文献一致的结果。     

Synchronization-based trajectory generation method for a robotic suit using neural oscillators for hip joint support in walking

A new synchronization-based trajectory generation method is proposed for a robotic suit that is designed to assist walking by supporting the hip joints. Neural oscillators are connected to each hip joint of the robotic suit to synchronize the suit’s movement with the human user’s movement (outer synchronization). At the same time, mutual inhibition is incorporated between the neural oscillators on the left and right hip joints of the suit to help maintain a human-gait-like anti-phase relationship (inner inhibition). We developed a two-degree-of-freedom robotic suit, which consists of two actuators located where the human hip joints are. Each actuator has a built-in torque sensor, which measures the mutual joint torque generated if any difference arises between the movement of a user and that of the suit. The mutual joint torque serves as input to neural oscillators, which control each actuator of the robotic suit through outer synchronization with the mutual joint torque and inner inhibition. The inhibitory weight, used to adjust the inhibitory strength between neural oscillators, is designed in a series of simulations. We conducted walking experiments to show the validity of our proposal for walking assistance of the robotic suit with mutual inhibition between neural oscillators.     

MEMS交叉梳齿光栅设计和优化

采用MEMS技术设计和制造了一种由梳齿驱动器驱动的新型交叉梳齿光栅,同时优化了该光栅的驱动器结构,着重分析了优化驱动器结构对光栅机械特性和光学传感特性的影响,优化后的光栅相对于未优化时具有更大的位移、更好的光学传感特性。基于PolyMUMPs工艺制作了梳齿驱动器驱动交叉梳齿光栅,并逐步分析了该光栅的加工步骤。结合有限元分析软件,对该MEMS光栅的机械特性进行了分析。分析结果表明,在85V下,该光栅驱动器的位移为2.7μm,而实际测量的位移为2.1μm。通过对该光栅驱动器结构进行优化,得到在同等电压下优化后的光栅驱动器位移较未优化时有显著提高,在85V时,优化后的MEMS光栅驱动器的位移为4.3μm。根据傅里叶光学理论计算得到,该光栅的传感灵敏度与驱动器位移成正比,经过计算得到优化后MEMS光栅的光学传感曲线更加陡峭,具有更好的传感特性。     

双通道红外耦合旋转连接器

提出一种新型双通道旋转连接器。该连接器应用红外无线技术耦合光信号通过旋转面,可保证信号持续传输。分析了连接器的设计原理,并测试了旋转器固定和旋转两部分的转配误差引起的离轴距离、轴向距离及其相对转动对信号传输的影响。试验结果表明：只要旋转连接器的零件加工和装配精度符合设计要求,装配误差的影响可忽略;当旋转器两部分相对转动时,系统实际的传输速率与静态时的速率相同,均为1．46Mbps;此连接器对机械加工和装配精度的要求显著降低,生产成本减少。     

Electro-mechanical modelling and identification of electroactive polymer actuators as smart robotic manipulators

Electroactive polymer (EAP) actuators, also known as artificial muscles, have remarkable properties such as low energy consumption, low weight, low actuation foot-print, compliance and bio-compatibility. Several methodologies have been proposed to model and analyse their quasi-static bending behaviour with negligible attention paid to their dynamic behaviour. We, therefore, report on an enhanced methodology to model their highly non-linear bending behaviour by treating them as smart and soft robotic manipulators. The methodology consists of an inverse kinematic model and a dynamic model. The proposed methodology accurately estimates the EAP actuator’s whole shape deflection using optimization-based inverse kinematic solutions integrated with an electro-mechanical dynamic model. The experimental and numerical results are presented to show the effectiveness of the soft robotic manipulator model in estimating the highly non-linear bending behaviour of the polypyrrole electroactive polymer (PPy-EAP) actuators. The proposed methodology can easily be extended to other bending type actuators and active smart manipulators.     

2 m级望远镜主动调节侧向支撑机构设计与优化

基于某2 m轻量化SiC主镜,设计了一种新型主动调节侧支撑机构。先分析常用的侧向支撑机构的结构形式和特点;再设计由位移促动器、柔性铰链结构和嵌入杠杆系统等部件组成的主动调节支撑机构;最后,对机构的支撑力和移动量进行有限元分析,并且搭建实验平台,对其进行刚度和调节能力测试。试验结果表明:当支撑力为562.55 N时,杠杆结构中位移促动器承受的力为97.57 N,大大降低了位移促动器的刚度、强度要求;位移促动器行程为0.065 mm,是支撑杆中的22倍,大大降低了位移促动器分辨率要求;试验测得刚度为1 225 N/mm,达到了设计要求,表明这种柔性杠杆支撑系统具有很好的工程应用能力。     

Varying mechanical compliance benefits energy efficiency of a knee joint actuator

In the field of wearable robots, actuator efficiency and user safety are frequently addressed by intentionally adding compliance to the actuation unit. However, the implications compliance has on the actuator’s overall performance in different conditions and activities are not fully understood, largely due to single task-focused experimental evaluations of these devices. To overcome this, our paper analyzes the effects that changing mechanical compliance has on the actuator’s overall performance in different ideal conditions in an experimental test setup. The torque performance and electrical energy consumption of an orthotic, adjustable-compliance knee joint actuator are evaluated during emulated walking and sit-to-stand-to-sit movements. Furthermore, the feasibility of combined operation of a dual mechanical compliance configuration during walking is investigated, and its outcomes reported in this work. The results demonstrate that varying mechanical compliance can lead up to 50% energy savings compared to a no-compliance configuration and show that, in general, changing compliance level leads to either energy-optimal or power-optimal actuator performance, but not both.     

压电叠堆电静液作动器Simscape模型与实验研究

将海德福斯螺纹插装换向阀集成到压电叠堆电静液作动器中,形成一体化集成式双向运动的压电叠堆电静液作动器。基于压电叠堆电静液作动器的物理系统,采用Simscape搭建压电叠堆电静液作动器系统模型。对比了在不同蓄能器偏压、不同电压峰值条件作用下,压电叠堆电静液作动器的实验输出流量与仿真输出流量;以及换向阀换向周期为4s时,压电叠堆电静液作动器的实验输出位移与仿真输出位移,验证了搭建的Simscape模型的准确性。在系统模型得到验证的基础上,分析发现阀片的回流现象是造成压电叠堆电静液作动器在高频驱动时输出流量衰减的原因。     

Recurve piezoelectric-strain-amplifying actuator architecture

Various external and internal leverage devices have been developed to amplify strain; however, these devices are commonly inefficient due to transmission losses and can be difficult to pack into constrained application volumes. A Recurve actuator architecture has been designed which amplifies direct material strains and allows for construction of highly compact, high-energy-density actuator arrays. The Recurve architecture enables arrays that can be tailored to produce specific force and displacement output and can be configured in a variety of ways to make efficient use of available design space. This paper describes a Recurve actuator architecture and presents a quasi-static model relating voltage, force, and deflection along with experimental results for fundamental Recurve actuator elements     

Infinite rotational motion generation and analysis of a spherical parallel manipulator with coaxial input axes

This paper presents a novel framework for the analysis of a 3-RRR spherical parallel manipulator with coaxial input axes (coaxial SPM) with the focus on its infinite rotational motion capabilities and its effects on the manipulator’s characteristics. The framework consists of three phases. At first, an approach for obtaining unique solutions of forward and inverse kinematics problems is introduced for setting up univocal relation between coaxial SPM’s input joint positions and orientation of its end-effector. At the second phase, a method for generating infinite rotational motions of an end-effector is formulated. The third phase outlines numerical computation procedures of the coaxial SPM’s workspaces in the joint and Cartesian spaces, excluding singularity configurations and mechanical collisions of SPM’s links during infinite rotational motion. A 3D design model and an experimental prototype of the coaxial SPM is presented and utilized for numerical analysis and experimental verification of the presented framework supplemented by an accompanying video demonstration.     

压电作动器在微力微位移装置中的应用

在微力微位移装置中采用闭环控制压电作动器实现微位移进给和微力加载，设计了加载机构，建立加载机构的压电作动器输入电压、加载装置输位移和输出力之间的关系。通过电容测位移仪检测输出位移，实验得到加载系统刚度，根据压电作动器输入电压、加载装置刚度，计算出加载力大小。该方法为微机械力学性能测试仪打下了基础。