果蔬采摘欠驱动机械手爪设计及其力控制

为了实现果蔬的无损采摘,采用欠驱动原理设计出一种结构更简单、通用性更强的末端执行器。欠驱动机构是指驱动器数目少于机构本身自由度数目的机构,基于欠驱动原理设计的机械手结构简单可靠,抓取物体时具有形状自适应能力,手指可完全包络物体,可以通过最大接触力的闭环力反馈控制来实现无损采摘。基于这一设计思想设计出仅靠一个电动机驱动三个手指的机械手爪,通过理论分析、手爪机构设计与建模、结构参数优化,确定设计尺寸制出机械手爪,设计控制电路结合力反馈控制进行抓取试验。试验结果表明该手爪能实现期望的抓取与最大接触力控制功能,并具有控制简单可靠、抓取稳定、不损伤果实等特点。     

拟人机器人手多指欠驱动机构研究

欠驱动机构具有增加抓取稳定性、降低控制难度等优点得到广泛研究.与实现单个手指的多关节动力传递的传统欠驱动机构设计思想不同,提出了一种新型多指欠驱动机构.该机构利用设置于关节轴上的扭簧实现了单个电机对多个手指根部的驱动.经分析,给出了该机构的主要参数设计原则.该机构可以作为拟人机器人手的食指、中指、无名指和小指的根部关节,使机器人手在抓取物体时,四个手指能够自动适应不同形状和尺寸的物体,产生适当的抓持力,抓取稳定性高,控制容易.     

三指灵巧手运动学分析及抓持仿真

参考人手的结构特征,设计了一种三指灵巧手,手指采用模块化设计,各手指结构相同。手指各主动关节均由直流伺服电机驱动,通过锥齿轮和钢丝绳传动机构传动,直流伺服电机和传动机构均配置在手指内部。采用D-H法建立手指坐标系,推导出运动学正、逆解,为灵巧手控制和抓取规划的研究奠定基础。运用仿真软件A D A M S对灵巧手抓持球体过程进行仿真分析,结果表明三指灵巧手在其工作空间内能够实现对物体的精确抓取。     

具有形状自适应的欠驱动拟人机器人手指

为了实现使用较少驱动器获得较多的自由度,从而在不增加控制难度的前提下,更好地抓取物体以及增加手的拟人化,需要研究欠驱动机械手指装置。提出了一种新的设计思想,以此为指导设计了一种机械手指装置,并对其主要设计参数进行了详细分析。试验证明,该装置可以作为机器人拟人手的一个手指或手指的一部分,用以实现机器人拟人手较少驱动器驱动较多的手指关节自由度,并具有抓取不同形状、尺寸的物体的自适应性,降低了装置对控制系统的要求。该装置外形与人手的手指相似,结构简单、可靠、易加工、体积小和重量轻。     

灵巧节能的单自由度仿真机械手驱动机构设计

为解决机器人自动装配、医学康复断指再造等多接触抓取装置驱动元件多,结构复杂且笨重的问题,设计了一种灵巧节能的单自由度仿真机械手的驱动机构,推导了各指节间的运动关系方程,利用ADAMS建立了其参数化仿真模型,分析了特定构件尺寸的机构运动轨迹与人手抓取轨迹的差距,进而提出满足人手抓取轨迹、驱动力矩小、各构件尺寸小的驱动机构的优化数学模型,经NSGA-II算法获得与人手抓取轨迹相差无几的多个最优方案,并用参数化模型进行了验证。设计结果表明,所提出的驱动机构仅需一个驱动元件即能实现手指各关节的灵巧运动,且结构尺寸小,满足节能环保的要求,是仿真机械手设计的新尝试。     

欠驱动仿人机器人手爪的精确捏取与包络抓取研究

研制出一种基于欠驱动机构的仿人机器人手爪,分析了手爪可实现的2种抓取模式(精确捏取和包络抓取),应用力矩平衡分析了精确捏取模式下末关节对物体的作用力与输入转矩的关系,应用虚功原理分析了包络抓取模式下各关节对物体的作用力与输入转矩的关系,并比较了2种抓取模式的抓取质量.最后在COSMOSMotion仿真环境中模拟了2种模式对圆柱形物体的抓取,验证了对抓取质量的分析.     

欠驱动机器人手指实验平台的设计

基于三关节绳索驱动的欠驱动机器人手指,设计了手指实验平台.该实验平台由平台机构、平台控制系统和VICON红外光点三维运动分析系统组成.平台机构采用海顿直线步进电机驱动导轨滑块,从而牵引绳索控制手指弯曲和伸展;平台控制系统采用DSPF2812作为主控制器,通过驱动器控制直线步进电机的转动;VICON红外光点三维运动分析系统采用6台VICON红外摄影机对标记点进行运动捕捉,其数据通过VICON资料处理器导出至PC端进行处理.实验平台可以对三关节欠驱动机器人手指进行抓取性能和运动轨迹的分析.     

机器人手可变抓取力机构研究

根据物体轻重程度和表面软硬程度，拟人机器人手在抓取时应采用不同的抓取力，研制变抓取力手具有重要意义。分析了传统的变抓取力手指机构实现原理，得出变抓取力手指实现的关键。为克服传统机构的不足，提出了一种新型变抓取力手指机构设计思想，具体设计并实现了该变抓取力手指机构，该变抓取力手指机构能够应用于各种驱动类型的手指上。此变抓取力手指机构被应用到拟人机器人手——TH-1手食指的2个关节中。抓取实验证明，TH-1手能够稳定抓取不同尺寸的常见物体．     

一种欠驱动苹果采摘机器人末端执行器的设计

提出了一种实用型欠驱动苹果采摘机器人三指末端执行器,并运用Unigraphics NX进行了机构设计及三维模型的创建。通过设计多指节手指和腱绳结构,以达到提高机构抓取灵活性的目的。基于手指抓取动作的运动原理,分析了腱绳力与关节转矩之间的关系。以保证不损伤苹果表面的极限载荷为设计约束条件,以实现机构运动的可靠性和灵活性为目标,设计了抓取机构的关键零件扭簧,确定了扭簧的结构参数。这种新型欠驱动末端执行器可以有效提高机构的灵活性和适用性,对不同尺寸、近球状的其他果实,具有一定的抓取适用性。     

混合工作模式欠驱动手设计及其接触力分析

机器人手目前主要应用于机器人与环境的交互.传统欠驱动机器人手的手指末端运动轨迹并不是一条直线,这种运动轨迹使得它们无法抓取桌面上较薄的物体以及小物体.为了克服这个缺陷,许多研究者在欠驱动手结构中加入了直线机构,使其能够捏取平台上的物体,但目前存在的结构均为双指关节结构,相对于三关节手指其抓取范围较小且适用场合较少.为了...     

Development of Gesture-Changeable under-actuated Humanoid Robotic Finger

Robotic fingers, which are the key parts of robot hand, are divided into two main kinds: dexterous fingers and under-actuated fingers. Although dexterous fingers are agile, they are too expensive. Under-actuated fingers can grasp objects self-adaptively, which makes them easy to control and low cost, on the contrary, under-actuated function makes fingers feel hard to grasp things agilely enough and make many gestures. For the purpose of designing a new finger which can grasp things dexterously, perform many gestures and feel easy to control and maintain, a concept called "gesture-changeable under-actuated" (GCUA) function is put forward. The GCUA function combines the advantages of dexterous fingers and under-actuated fingers: a pre-bending function is embedded into the under-actuated finger. The GCUA finger can not only perform self-adaptive grasping function, but also actively bend the middle joint of the finger. On the basis of the concept, a GCUA finger with 2 joints is designed, which is realized by the coordination of screw-nut transmission mechanism, flexible drawstring constraint and pulley-belt under-actuated mechanism.Principle analyses of its grasping and the design optimization of the GCUA finger are given. An important problem of how to stably grasp an object which is easy to glide is discussed. The force analysis on gliding object in grasping process is introduced in detail. A GCUA finger with 3 joints is developed. Many experiments of grasping different objects by of the finger were carried out. The experimental results show that the GCUA finger can effectively realize functions of pre-bending and self-adaptive grasping, the grasping processes are stable. The GCUA finger excels under-actuated fingers in dexterity and gesture actions and it is easier to control and cheaper than dexterous hands, becomes the third kinds of finger.     

模块化磁吸五指灵巧手结构设计与控制研究

针对目前五指灵巧手自由度低、拆装繁琐等问题,设计出一种模块化、易拆装、直驱式11自由度五指灵巧手.通过永磁铁实现手指关节间的快速拆装,每个手指关节至少有±90°转动范围;通过对大拇指转动角度的特殊设计,可实现灵巧手左/右手模式直接切换以及双侧同时抓取.通过3D打印制作了五指灵巧手样机.针对灵巧手多传感器造成控制系统复杂...     

A biomimetic hand employing a dual actuation scheme

This paper presents a biomimetic hand that employs a hybrid actuation scheme that provides large grasping forces and swift motion. This hybrid hand is made up of a red muscle actuator used for grasping and a white muscle actuator used for fast and accurate movement. A parallel structure utilizing fully back-drivable linear motors has been adopted for the white muscle actuators. The red muscle actuators employ a Micro Hydraulic Compressor Converter (MHCC), hydraulic cylinder, and a tendon. The tendon structure enables a passive shape adaptation during the act of grasping an object. Safety in regards to impact is achieved through the back-drivability. The hybrid hand is comprised of two fingers and a thumb. The fingers and the thumb all have 2 degrees of freedom. The hybrid actuation is only applied to the fingers. The experiment results indicate that a grasping force of 94N is generated through the red muscle actuator and a 3 Hz sinusoidal motion is obtained from the white muscle actuator.     

Mechanical design,modeling, and identification for a novel antagonistic variable stiffness dexterous finger

This study traces the development of dexterous hand research and proposes a novel antagonistic variable stiffness dexterous finger mechanism to improve the safety of dexterous hand in unpredictable environments, such as unstructured or man-made operational errors through comprehensive consideration of cost, accuracy, manufacturing, and application. Based on the concept of mechanical passive compliance, which is widely implemented in robots for interactions, a finger is dedicated to improving mechanical robustness. The finger mechanism not only achieves passive compliance against physical impacts, but also implements the variable stiffness actuator principle in a compact finger without adding supererogatory actuators. It achieves finger stiffness adjustability according to the biologically inspired stiffness variation principle of discarding some mobilities to adjust stiffness. The mechanical design of the finger and its stiffness adjusting methods are elaborated. The stiffness characteristics of the finger joint and the actuation unit are analyzed. Experimental results of the finger joint stiffness identification and finger impact tests under different finger stiffness presets are provided to verify the validity of the model. Fingers have been experimentally proven to be robust against physical impacts. Moreover, the experimental part verifies that fingers have good power, grasping, and manipulation performance.     

欠驱动多指节机器人手的抓力分析

对欠驱动多指节机器人手的抓力进行了分析,给出了直指和曲指抓取物体时的抓力方程,并对手指抓力作了动态仿真。手指抓力分析为多指节手的机构与力控制设计提供了理论基础。     

多指灵巧手的最佳灵巧性设计

首先讨论了多指抓持系统中抓持物体的灵巧性 ,指出该系统的灵巧性取决于各手指的性能。然后 ,分析了单个手指 (单个操作器 )的灵巧度 ,通过对手指灵巧性的要求 ,确定手指 (操作器 )的最佳工作区域。最后 ,提出具有最佳灵巧性的多指灵巧手的设计准则 ,并利用两指手、三指手的设计 ,表明了多指手的最佳灵巧性设计     

十自由度假手结构设计及动力学建模仿真

针对传统假手运动不够顺畅和不够灵活的缺点,参考人手的结构,设计了一种五指十自由度的假手。该假手采用模块化的设计思想,除拇指外的四指尺寸结构完全相同,每个手指具有2个屈曲自由度;拇指具有屈曲和侧摆2个自由度。在此结构的基础上,针对拇指和食指进行了动力学建模,并通过Matlab数值仿真和ADAMS虚拟实验的对比,验证了动力学模型的正确性。     

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。     

Detection of kinematics parameters of index finger movement with high-speed video camera

Synergic movement of finger＇s joints provides human hand tremendous dexterities, and the detection of kinematics parameters is critical to describe and evaluate the kinesiology functions of the fingers. The present work is the attempt to investigate how the angular velocity and angular acceleration of the joints of index finger vary with respect to time during conducting a motor task. A high-speed video camera has been employed to visually record the movement of index finger, and miniaturized （5-mm diameter） reflective markers have affixed to the subject＇s index finger on the side close to thumb and dorsum of thumb at different joint landmarks. Captured images have been reviewed frame by frame to get the coordinate values of each joint, and the angular displacements, angular velocities and angular acceleration can be obtained with triangle function. The experiment results show that the methods here can detect the kinematics parameters of index finger joints during moving, and can be a valid route to study the motor function of index finger.