仿人手指的运动学分析与研究

设计了一种具有独立电机驱动、采用钢丝绳耦合连杆机构传动的多自由度仿人手指,并建立了手指机构的简化模型。同时,基于运动学分析得到了手指运动学模型正解,选取适当手指机构尺寸及各关节的转角范围,通过仿真获得了指端的工作空间。分析比较了有无耦合连杆2种手指各指节的运动位移与时间之间的关系,采用的耦合连杆传动,克服了无连杆传动过程中3个指节间在各个方向上的运动位移明显不一致性。为假手的抓取动作规划、运动姿态控制以及结构优化设计提供了进一步研究的基础。     

新型集成化仿人手指及其动力学分析

研究了一种新型的集成化仿人手指。这种手指有两个主要特点:采用微直线驱动器和腱传动相结合的方式驱动手指,实现了机械本体和驱动系统的集成;采用差动机构设计了轴线相交的2自由度基关节,手指末端的两个关节是机械耦合的。系统地分析了手指的运动学和动力学,为灵巧手的优化设计和控制奠定了基础。     

线性空程传动耦合自适应机器人手研制

传统耦合自适应手指采用并联的两套传动机构实现先耦合后自适应的复合抓取模式,存在机构复杂、内耗大和弹簧选型困难等不足。针对此问题,设计了一种新的耦合自适应欠驱动手指机构——COSA-LET手指。COSA-LET手指包括多个齿条、双拨杆、双限位凸块和双弹簧等,由一个电机和串联传动机构驱动两个关节。COSA-LET手指利用反向双齿条和带弹簧及凸块限位的齿轮实现耦合联动功能,利用关节轴弹簧将电机动力分解到两个关节轴,通过双拨杆线性空程传动的延时拨动效应解决了自适应阶段的解耦问题。手指抓取受力分析和实验结果表明,所研制的带有3个COSA-LET手指的COSA-LET机器人手实现了耦合与自适应复合抓取功能,能够根据被抓取物体的大小、形状和位置,在耦合与自适应之间自主切换抓取模式。     

五指仿人机器人灵巧手DLR/HIT Hand II

基于机电一体化设计思想和最新的驱动技术,研制DLR/HIT II仿人灵巧手。该灵巧手由5个相同结构的模块化手指和1个独立的手掌构成,每个手指有4个关节、3自由度,所有的驱动器和电路板均集成在手指或手掌内。采用新型的体积小输出力矩大的盘式无刷直流驱动电动机、质量轻的谐波减速器、齿形皮带等的驱动传动方案,使手指的体积和质量得到显著减小;采用钢丝耦合传动方案,实现手指末端两个关节的1:1耦合运动;手指具有位置、力/力矩、温度等多种感知功能。层次化的灵巧手硬件结构由手指电气系统、手掌电气系统和PCI总线控制卡等组成,灵巧手具有点对点串行通信、CAN以及网络等多种通信接口。在灵巧手的外观设计中,将外观设计与灵巧手的本体设计融为一体,实现灵巧手与人手相近的体积和外观。5指灵巧手的质量为1.5 kg,手指的指尖输出力10 N。     

推拿灵巧手的设计及其位置分析与仿真

为了提高推拿机器人的自动化程度,完成了多自由度推拿灵巧手的结构设计和运动学分析。该灵巧手含有食指、中指、无名指和大拇指4只手指,每个手指拥有指掌和指指两个关节,食指、中指、无名指3只手指的两个关节分别联动,使得本灵巧手共4个自由度。此外,本灵巧手创新性地采用了曲柄摇杆机构驱动指指关节,有利于提高捏法操作中运动的连续性和周期性,避免电机的频繁换向,延长电机的使用寿命。利用MATLAB的数值分析和ADAMS运动仿真功能,验证了本灵巧手实现捏法操作的运动性能。     

基于钢丝绳-绳套传动的手康复机器人的设计与仿真

为了帮助患者进行手指康复训练,设计了一种新型手康复机器人。首先对人手食指关节进行建模,并对食指关节的耦合运动进行分析。提出了一种连杆+铰链的组合执行结构,连杆结构可以避免相邻手指间的运动干涉,铰链结构则简化了控制方式。使用钢丝绳传动作为机器人系统的传动方式,使得驱动模块和执行模块分离,减少了手部负载。然后在Por/E中设计康复机器人的三维模型,并将模型导入ADAMS中对该机器人进行运动学仿真。仿真结果表明,各关节角度均可达到食指日常活动所需,所设计的机器人结构满足康复训练的要求。最后分析了钢丝绳传动的力学特性,推算了在任意空间姿态下,钢丝绳中的张力计算公式。     

钢丝绳传动机器人运动学的回路分析方法

研究分析了一类2N条钢丝绳驱动N个自由度机器人的运动学,其运动学分析可通过推导除去钢丝绳后的开环链机器人关节角位移与末端执行器之间的运动学模型和关节角位移与电机转子角位移之间的运动学模型两个步骤完成。在运动学分析的基础上,提出了用回路矩阵和等效半径矩阵描述钢丝绳传动机器人运动学的回路分析方法。根据钢丝绳传动原理,通过观察法可直接列写回路矩阵和电机驱动空间等效半径矩阵,从而得到电机转子角位移与关节角位移之间的映射关系模型,解耦了由于钢丝绳传动导致机器人关节之间的运动耦合。实现了电机驱动空间、关节空间和笛卡尔空间之间完整的运动学映射,加快和简化了钢丝绳传动机器人运动学的建模和分析过程。最后,以Utah/MIT手指为例进行了运动学分析,比较Matlab运算和Solidworks Motion仿真的末端运动轨迹,验证了回路分析方法的正确性。     

多指护理灵巧手的优化

从手指关节运动副型式、手指指数和手掌、手指结构、手指材料、各个关节运动的驱动方式以及传动方式、各关节截面的结构型式、传感器的选择和布置等7个方面对灵巧手进行优化分析。考虑到一般性和通用性,对各手指之间的相对位置及姿态、各关节的长度及回转关节的回转角度范围,运用拟人法,类比法,建立优化目标函数和约束条件进行优化计算,设计出一种用于护理机器人上的带手掌的3指9关节灵巧手。对灵巧手的具体结构作了分析,绘出了灵巧手的三维结构模型。优化的护理灵巧手扩大了抓取范围,安装了灵巧手的护理机器人,减轻了护士的劳动强度,提高了护理质量。     

应用于核磁环境的双腱鞘传动分析与研究

乳腺活检机器人在核磁环境下因为材料及驱动的兼容性一直难以同时获得高质量的扫描图像和精准的活检针介入。因此提出一种能够满足核磁兼容并应用于机器人上具有双折线螺纹的可以实现远距离、大行程的双腱鞘柔性传动系统。首先,针对具有双折线螺纹的双腱鞘远程传动系统,对其单关节进行了摩擦力分析。通过对单关节双腱鞘传动的非线性耦合特性进行分析,建立了双腱鞘双向耦合传动模型。并搭建了单关节双向耦合传动实验平台,且对其进行了分析及补偿实验。其次,搭建了双腱鞘传动的多关节乳腺活检机器人实验平台,并对双腱鞘传动的多关节乳腺活检机器人进行了双向耦合运动误差分析以及补偿实验。补偿后针尖进入组织的X、Y、Z 3个方向平均误差分别为1.39、1.89和1.60 mm。实验结果表明,双腱鞘传动的多关节乳腺活检机器人可以满足核磁环境下乳腺活检的精度需求。     

六杆仿生手指机构的最优化设计

假肢手指机构是一种典型的仿生机构,其设计要求是:(1)再现手指的基本功能;(2)运动姿态接近人指;(3)要求机构具有较高的传动效率.本文选择指端轨迹、指节的运动姿态和传动效率作为优化过程所追求的目标,并选择具有两个交叉封闭环的六杆机构作为实现设计要求的基本机构。优化结果获得了一组能较好地再现关节式手指基本功能的机构尺寸,利用所得到的机构可以实现握拳动作,并具有很好的拟人效果。     

人类手指抓取过程关节的运动规律研究

根据手指外科解剖学原理以及手指关节的运动特性，对单手指的抓取运动进行了分析，讨论了两种常见的运动规律的角位移、角速度和角加速度的特点。通过一个独特的实验，对手指运动过程的关节角位移进行了测定并对单手指关节转角运动进行解析模拟和对比，结果表明，关节转角的运动符合一定的运动规律。研究结果对手指的运动仿真和控制具有指导意义。     

一种自适应拟人手指抓持力分析与结构优化

采用齿轮齿条传动机构，设计了一种新型自适应拟人手指。该手指自身不带驱动器，适合抓取不同形状、尺寸的物体，使机器人多指手以较少的驱动器驱动较多关节自由度。电机的数量大大减少使机器人手具有许多优点。另外，该手指与人的手指相似，适合用于拟人多指手。分析了该手指抓持力与其设计参数的关系，提出了该手指的结构优化设计原则。     

超声电机驱动五指灵巧手的设计与仿真

设计一个由超声电机驱动的仿人五指灵巧手,由于超声电机的一些优点,使得该五指灵巧手与人手相仿,共有20个独立自由度,重量不足1000 g。为了检验设计方案是否能达到预期的效果,运用ADAMS分析软件对模型进行了运动学和动力学的仿真,仿真结果表明设计方案合理可行。     

FORCE FEEDBACK DATAGLOVE BASED ON PNEUMATIC ARTIFICIAL MUSCLES

An exoskeleton force feedback dataglove is developed, which uses the pneumatic artificial muscles as actuators. On the basis of the simplified hand model, the motion equation is deduced according to the theory of Denavit-Hartenberg. The model of the equivalent contact forces exerted by the object on the finger is proposed. By the principle of virtual work, the static equilibrium of finger is established. The force Jacobian matrix of finger is calculated, and then the joint torques of the finger when grasping objects are obtained. The theory and structure of the force feedback datagolve are introduced. Based on the theory of motion stabilization of four-bar linkage, the flexion angles of joints are measured. The torques on finger joints caused by the output forces of pneumatic artificial muscles are calculated. The output forces of pneumatic artificial muscle, whose values are controlled by its inner pressure, can be calculated by the joint torques of the finger when grasping objects. The arms of force, driving torques and the needed output forces of pneumatic muscle are calculated for each joint of the index finger. The criterion of output force of pneumatic muscle is given.     

多自由度超声电机研究的一些新进展

多自由度超声电机是从九十年代初开始研究的、在单自由度超声电机的基础上发展起来的一种新型电机。由于这种电机能提供两个或两个以上自由度的运动，且具有超声电机本身的独特优点，因而有广阔的应用前景。文中列举了几种最新出现的多自由度超声电机，阐述了它们的结构、工作原理和特点，为关注这方面发展动态的同行们提供参考。     

Maximum finger force prediction using a planar simulation of the middle finger

Maximum isometric finger-grip forces were predicted using a biomechanical model for plane motion of the middle finger. In the course of this study, mathematical representations of tendon displacement, the moment arm of tendon at the finger joints and muscle force-length relationship were investigated. The information gathered was applied to the model to estimate the maximum grip force of the middle finger gripping cylinders of different sizes. Muscle force per unit physiological cross-section area of 30 N/cm2 resulted in good agreement with measured force. However, for finger postures having an acute proximal interphalangeal joint angle, the estimated force was greater than that measured. Various joint angles were applied to the model to simulate the wrist and finger postures not limited to the cylinder grip. In general the finger force was greatest with the wrist in its extended position and at acute flexion of the proximal interphalangeal joint. The maximum finger force occurred at reduced metacarpophalangeal joint angles as the wrist joint changed from an extended position to a flexed one. It is also postulated that muscle force-length relationship is an important factor in muscle force predictions. The data obtained by this research are useful for the design of handles and the current model is applicable to the analysis of hand postures for workers using hand tools.     

Tribology of human and artificial joints.

Studies of human joint lubrication mechanisms have led to the conclusion that under normal healthy conditions they are fluid film lubricated. The main features responsible for allowing this mechanism to operate are the dynamic nature of the loading and the compliance of the bearing surfaces (articular cartilage). In contrast, artificial joints, being made of much more rigid materials, have been demonstrated to be lubricated by a mixed regime, where some load is carried by the fluid film and some by solid to solid contact. Since some surface contact takes place then wear remains a problem and friction is much higher than in human joints. The use of compliant surface bearings for artificial joints has been explored and shown to be of great advantage, reproducing the effects of natural joints. However, elastomeric materials are known to degrade in aqueous solutions so this aspect has been examined to ensure a reasonable life in the human body. Joints of the lower limb--hip, knee, and ankle--have similar load and motion patterns and behave in a similar way in terms of lubrication. Joints of the hand are not in any way similar in their behaviour and so a typical upper limb joint, the finger, has been studied to see if improvements can be made to the design of replacement artificial joints. Novel suggestions like plastic on plastic joints have been shown to be an alternative which is worthy of further consideration.     

Precision control system of two-DOF stage with linear ultrasonic motor

Using an appropriate control method, linear ultrasonic motors can be used in applications requiring high position accuracy. In this paper, a closed loop PI control system is designed to achieve high position accuracy during the control of a two-DOF stage driven by linear ultrasonic motors. Two ultrasonic motors are mounted on the stage to generate motion in two orthogonal directions. The PI control algorithm is used to increase the stability and accuracy of position control. The x-axis mover covers 30 mm forward and backward in less than 0.3 s settling time and the y-axis mover in less than 0.4 s. Experimental results denote that the control strategy proposed in this paper appears to have high efficiency, quick response, and high accuracy.     

The validity of using a video-based motion analysis system for measuring maximal area of fingertip motion and angular variation

The aim of the study was to verify the application of a three-dimensional video motion analysis system to evaluate maximal fingertip motion area and angular variation of the hand by comparison and correlation with videofluoroscopic analysis. Eight normal subjects were recruited in this study. The maximal motion area of the fingertip and the angles of the metacarpal phalangeal (MP), proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints in performing five sequential postures for functional evaluation of the hand were measured using a video motion analysis system and a fluoroscopy system respectively. The results indicated that the intraclass correlation coefficient (ICC) of the calculated maximal fingertip motion area between the two methods was 0.9597. The ICC for total active motion (TAM) measurements of three finger joints was 0.940 between the surface and bony landmarks by fluoroscopy, 0.952 between the surface landmarks from fluoroscopy and motion analysis, and 0.927 between the bony landmark from fluoroscopy and surface markers from motion analysis. The ICC for angular measurements between three different paired assessments was 0.9650, 0.8896 and 0.8799 for the MP, PIP and DIP joints respectively. The results indicate that motion analysis is a practical method for assessing impairment of the hand.     

基于 sEMG 和肌肉骨骼模型的手指 多关节力矩耦合分析

手指内部力矩受表面肌电信号、肌力、手部姿态等因素影响而无法直接获取,为了实时且准确地获取手指各关节力矩以 及耦合力矩并应用于手部康复机器人的交互控制中,提出了一种基于表面肌电信号和肌肉骨骼模型的手指多关节力矩和耦合 力矩分析与实时获取方法。 首先设计了自适应手指关节角度采集系统,通过实验同步采集指浅屈肌与指伸肌的肌电信号以及 手指各关节的角度数据,建立手指多关节力矩模型,从而获取手指各关节力矩。 然后建立手指 D-H 模型,结合虚功原理获取手 指的耦合力矩。 最后,辨识了手指多关节力矩模型的参数,并通过 OpenSim 软件获取了仿真力矩。 计算力矩与仿真力矩的对比 结果显示:4 名被试 3 个关节力矩的均方根误差分别为 0. 156 7、0. 097 425、0. 084 95,证明了该方法能够实时并准确的获取手指 各关节力矩和耦合力矩,能够满足手部康复机器人交互控制准确性和实时性的需求。