SMA丝驱动的手指康复机器人设计及实验研究

为了研制一种轻便、可穿戴的仿生手指康复机器人,在分析手指肌肉骨骼生物参数及致动机理的基础上,设计了一种形状记忆合金丝(Shape Memory Alloy, SMA)驱动的软体柔性手指康复机器人,建立了其运动学和力学模型。以手套为结构设计的原型,通过控制SMA丝的收缩来模拟手指肌肉肌腱的收缩,从而实现辅助手指屈曲伸展运动的功能。试验研究了手指康复机器人的运动性能和抓握性能。试验结果表明,手指柔性康复机器人最大弯曲角度接近正常人手关节角度,最大指尖力可达18N,能完成日常所需的屈曲伸展以及抓握功能。     

基于PCL的一维形状记忆合金系统的开发与应用

智能材料的发展给结构设计带来新的方向,同时也给商用有限元软件的应用迎来新的挑战.由于MSC Nastran的局限性,尚不能很好地模拟一些智能材料.结合实际工程需要,利用Patran完善的前、后处理功能及二次开发语言,将一维形状记忆合金(Shape Memory Alloys,SMA)材料系统集成到Patran中,能方便地实现在Patran中定义其材料属性和对布置有SMA的驱动结构以及复合材料结构的快速建模分析,最后利用本文系统建立SMA复合梁以及SMA丝驱动的机翼后缘模型,并进行验证,证明此模块功能的正确性和有效性.     

基于DSP的变体机翼测控系统研究

针对一种形状记忆合金(SMA)驱动的变体机翼结构,设计了基于32位定点数字信号处理器(DSP)芯片TMS320F2812的测控系统.提出了一种测量与控制机翼偏转角度的方法,通过硬件设计和软件设计,结合DSP开发调试环境,进行了机翼结构单关节偏转角度控制实验,实验结果表明:控制效果较好,基本能达到控制要求,并为以后机翼的...     

基于形状记忆合金的四足步行机器人

利用形状记忆合金（Shape Memory Alloys,简称SMA）作为驱动元件，设计制作四足步行机器人，其动作靠电流的通，断来控制，本文介绍了这种机器人的具体的设计和制作方案，包括该机器人的运动原理，设计要点，结构组成和控制方式，并且对样机的相关参数作了评价。     

多元高斯声束模型相控阵超声传感器声场仿真

由于高斯函数积分的简单性,利用扩展多元高斯声束模型对矩形相控线阵超声传感器偏转聚焦时的辐射声场进行了理论计算,并在一种介质中与更精确的瑞利积分进行了分析和对比,在偏转角度不是很大的情况下,计算结果非常符合。利用该方法计算了传感器安装在契块上时固体试件中的声场分布,并在入射角大于10°(折射角大于20°)时,对结果进行了修正,使声场计算的偏转范围增大,进一步丰富了高斯叠加方法的适用范围。     

SMA驱动丝的建模与仿真

研究SMA动力学优化模型,针对形状记忆合金(SMA)驱动丝具有强非线性、迟滞效应等特性,为设计SMA驱动丝的自适应结构,提出建立SMA驱动丝模型并提供高效的仿真方法。采用有限元软件实现了受轴向载荷的SMA驱动丝的仿真建模。对本构模型是根据自由能的一维热-力学耦合模型,可以同时复现形状记忆效应和超弹性。数值仿真能够引起材料相变的非均匀温度和应变分布。仿真结果表明,建立热-力学耦合模型,可为设计SMA驱动丝的自适应结构计算提供可靠依据。     

基于东元交流伺服的SGS无损检测平台控制系统设计

为了实现分段γ扫描(SGS,segment gamma scanning)无损检测平台各部分传动装置的精确控制,选用高精度、高性价比的东元交流伺服作为平台动力源,采用C#语言编写上位控制软件,完成对传动装置的定位、运行、复位等精确控制。重点介绍了上位控制软件和伺服控制系统的设计。测试表明：传送定位误差小于1 mm,旋转角度误差小于1°,满足SGS无损检测平台的要求。     

近空间飞行器多模型软切换保性能非脆弱控制

针对可变机翼后掠角近空间飞行器存在严重非线性、强耦合等特性, 在考虑控制器存在摄动的情况下, 设计了可以平滑切换的多模型软切换保性能非脆弱控制方案. 首先利用可测前提变量将系统的工作空间划分为多个子空间, 然后在每一个子空间中根据给定的性能指标设计局部模糊鲁棒保性能非脆弱控制器. 由于采用了广义系统的设计方法, 有效地减少了求解的计算量和复杂度. 系统的全局控制器由各局部控制器进行模糊加权得到, 从而实现了软切换. 对变机翼后掠角近空间飞行器的仿真实验表明了所提方法是有效的.     

一种扩展小孔成像模型的鱼眼相机矫正与标定方法

鱼眼相机由于其超宽的视场范围（Field of view,FOV）（可以达到180°以上）,得到越来越广泛的应用. 常规的基于小孔成像模型的相机矫正与标定算法在超宽视场的鱼眼成像系统中已经不太适用,为了兼顾小孔模型的特点,本文提出了一种扩展小孔成像模型的鱼眼相机矫正与标定方法. 此方法是对小孔成像模型的进一步拓展,不仅具备小孔模型实现简单、适合人眼视觉效果以及相机标定方便等优点,同时将小孔成像模型适用的视场范围扩展到超宽视场领域. 其基本思路是:在利用小孔成像模型对鱼眼相机90°左右视场范围进行矫正与标定的基础上,使用非等间距的点阵模板,并结合直线拟合以及自然邻点插值算法,扩展小孔模型适用的视场范围. 本文使用鱼眼相机从不同的角度拍摄多幅模板图,完成鱼眼相机的矫正与标定. 通过求取的小孔成像模型参数实现相机的标定;对鱼眼相机拍摄的实际场景图进行畸变矫正测试,结果表明此方法能够很好地矫正鱼眼相机存在的畸变,得到符合人眼视觉效果的矫正图;单幅矫正图视场范围达到130°,结合不同角度拍摄的多幅模板图,可把矫正的视场范围扩展到180°.     

SMA微驱动器的设计方法

前言 微驱动器是微型机器人中的重要组成部分。形状记忆合金(SMA)用于微驱动器是一种极好选择。SMA体积越小,功重比越大;采用SMA驱动后可省略传动机构,使结构大为简化;同时可以实现精确控制。本文主要介绍SMA微驱动器的设计方法。     

Design and testing of a microgripper with SMA actuator for manipulation of micro components

The extremely high work-to-volume ratios of the SMA actuators make them suitable to be used as a powerful actuator in micro-scale manipulation. In this study, an easily manufacturable micro-gripper with shape memory alloy (SMA) wire actuator was designed and manufactured. The concept of the designed micro-gripper was based on flexible hinge structures to increase the deflection efficiency and strength. The size of microgripper was a significant criterion in our design. Also, innovative layout in locating of SMA wire caused the microgripper to gripe and manipulate a boarder range of objects. The finite element method was used to analyze and calculate the stress distribution and jaw’s deflection in the gripper. In order to verify the modeling results, an experimental analysis by building a set-up for micro-gripper and running tests were implemented and it showed a good agreement with the modeling results. The approximate size of the micro-gripper is about 12 × 10 mm and its maximum achievable deflection is 200 μm which is perceptibly higher than SMA actuated micro-grippers with the same size.

     

仿蚯蚓机器人蠕动装置的研究

仿照蚯蚓在孔内蠕动的过程,研制了一种在孔内行 走的机器人驱动装置．该装置主要由形状记忆合金(SMA)胀紧环, SMA螺旋弹簧和偏压弹簧等 组成．它可以在孔内象蚯蚓一样实现径向胀紧、纵向收缩、纵向伸长等动作．SMA元件的动 作可以靠通、断电来实现,SMA胀紧环通电时与孔壁贴紧,断电时松开;SMA螺旋弹簧通电时 收缩,断电时由偏压弹簧使其伸开．其动作过程由计算机控制和协调．该驱动装置结构简单 ,体积小、重量轻、柔韧性好、控制方便．该装置在电火花弯孔加工中得到了实际应用．本 文介绍了该装置的组成、工作原理、设计要点和控制方式．     

A new method for actuating parallel manipulators

This paper presents a new technique of actuating a parallel platform manipulator using shape memory alloy (SMA). This is a type of smart materials that can attain a high strength-to-weight ratio, which makes them ideal for miniature application. The work is mainly to develop a new SMA actuator and then incorporating the actuator in building the parallel manipulator prototype. The SMA used in this study is a commercial NiTi wire. The SMA wire provides an actuating force that produces a large bending and end displacement. A 3-UPU (universal–prismatic–universal) parallel manipulator using linear SMA actuators was developed. The manipulator consists of a fixed platform, a moving platform and three SMA actuators. The manipulator workspace was specified based on the restrictions due to actuator strokes and joint angle limits. System identification techniques were used to model both heating and cooling processes. An ON/OFF control was performed and the results showed closeness in simulation and experimental results. This study showed that shape memory alloy actuated beam can successfully be used to provide linear displacement. The built prototype indicates the feasibility of using SMA actuators in parallel manipulators.     

变截面Z型折叠机翼振动特性的有限元与实验分析

Z型变截面折叠机翼作为一种可变体机翼结构,不同的折叠角对机翼稳定性有着重要的影响,因此研究不同折叠角度下的特性参数对机翼动态稳定性有着重要的意义.本文首先设计加工了Z型变截面可折叠机翼结构的实验模型,通过建立与实验模型相匹配的有限元模型,仿真得到不同折叠角度下机翼的前5阶固有频率和振型,针对不同折叠角度下机翼的固有特性,通过扫频实验得到机翼前5阶固有频率和模态振型,以及横向外激励作用下三段翼的频响曲线,对比分析有限元仿真与实验结果,验证结果的可靠性,这将对机翼结构设计以及特性参数的选取提供参考依据.     

Composite stacking sequence optimization for aeroelastically tailored forward-swept wings

A method for stacking sequence optimization and aeroelastic tailoring of forward-swept composite wings is presented. It exploits bend-twist coupling to mitigate aeroelastic divergence. The method proposed here is intended for estimating potential weight savings during the preliminary aircraft design stages. A structural beam model of the composite wingbox is derived from anisotropic shell theory and the governing aeroelastic equations are presented for a spanwise discretized forward swept wing. Optimization of the system to reduce wing mass is undertaken for sweep angles of ?35° to 0° and Mach numbers from 0.7 to 0.9. A subset of lamination parameters (LPs) and the number of laminate plies in each pre-defined direction (restricted to {0°,±45°, 90°}) serve as design variables. A bi-level hybrid optimization approach is employed, making use of a genetic algorithm (GA) and a subsequent gradient-based optimizer. Constraints are implemented to match lift requirements and prevent aeroelastic divergence, excessive deformations, airfoil stalling and structural failure. A permutation GA is then used to match specific composite ply stacking sequences to the optimum design variables with a limited number of manufacturing constraints considered for demonstration purposes. The optimization results in positive bend-twist coupling and a reduced structural mass. Results are compared to an uncoupled reference wing with quasi-isotropic layups and with panel thickness alone the design variables. For a typical geometry and a forward sweep of ?25° at Mach 0.7, a wingbox mass reduction of 13 % was achieved.     

导弹异形卷弧翼安装选型

为在空中发射武器外形设计中引入异形卷弧翼,将其作为导弹主升力面,研究其相对于弹身的安装选型问题．模型设计采用1对异形卷弧翼,并将其沿弹体纵向平面对称布置．定义异形卷弧翼相对于弹身的安装位置角和安装偏角参数,选取2组计算模型,基于计算流体力学（Computational Fluid Dynamics,CFD）仿真计算评估这2个角度的变化对异形卷弧翼-弹身组合体纵向超音速气动参数的影响,得到组合体升力因数、阻力因数以及升阻比随2个角度参数变化而变化的规律．结果表明,在设计任务中,当安装位置角等于120°,安装偏角等于-10°时,组合体的升力因数和升阻比达到最大值．该方法可以改善导弹的升力特性,提高导弹的升阻比,使导弹获得更好的飞行性能．     

Measurement of static and dynamic mechanical behavior of micro and nano-scale thin metal films: using micro-cantilever beam deflection

We present the results of a novel micro-beam deflection test used to investigate the static and dynamic mechanical behavior of submicron-thick metal films. The method demonstrated in this study allows researchers to observe the motion of micro and nano-scale thin films responding to electrostatic loads, by means of laser reflection measurements at frequency rates of up to 500 Hz. Researchers fabricated a supporting frame and a novel triangular shaped “paddle” beam designed to provide uniform plane stress distribution while undergoing deflection. A simple geometric calculation, based on cantilever deflection, enabled the degree of strain to be determined, which in turn provided the Young’s modus for aluminum film of a given thickness. We also studied the dynamic behavior using the dynamic frequency response of the beam, generated by electrostatic forces under various loads and vacuum pressure conditions. Our results showed that air damping has a significant influence on the free damping behavior of specimens, and only a minor influence on damping frequency. We determined the loss angle and frequency using sweep frequency and free damping methods, which were very consistent with paddle resonant frequencies. The loss angle obtained from a simple silicon micro-beam was 2.001 × 10^−4°using the free damping method and 2.23 × 10^−4°using the sweep frequency method. The dynamic response loss mechanism measured in this experiment provides incentive for the further study of grain boundary motion and dislocation motion in thin films.