DESIGN OF A NOVEL DEXTEROUS ROBOT HAND

In the robotic community more and more hands are developed. Based on theexperience of HIT Hand and DLR Hand II, a smaller and easier manufactured dexterous robot hand withmultisen-sory function and high integration is jointly developed. The prototype of the hand issuccessfully built. It has 4 fingers in total 13-DOFs (degree of freedom). Each finger has 3-DOFsand 4 joints, the last 2 joints are mechanically coupled by means of four-bar linkage mechanism. Italso has an additional DOF to realize motion of the thumb relative to the palm. The fingertip forcecan reach up to 10 N. Full integration of mechanical body, actuation system, multisensory system andelectronics is a significant feature. DSP based control system is implemented in PCI busarchitecture and the serial communication between the hand and DSP needs only 2 lines.

Cartesian impedance control of dexterous robot hand

Presents a novel compliant motion control for a robot hand using the Cartesian impedance approach based on fingertip force measurements. The fingertip can accurately track desired motion in free space and appear as mechanical impedance in constrained space. In the position based impedance control strategy, any switching mode in contact transition phase is not needed. The impedance parameters can be adjusted in a certain range according to various tasks. In this paper, the analysis of the finger’s kinematics and dynamics is given. Experimental results have shown the effectiveness of this control strategy.

Design and modeling for a kind of humanoid dexterous hand with elastic palm

With dexterous hands, robots can improve the work scope and work ability significantly. As palms of the existing multi-hand robots are made of steel plates that have small contact area, the robots cannot grab firmly. In this study, a new five-fingered dexterous robot hand is developed. Having flexible palm with 17 degree of freedoms （ DOFs）, the hand can grasp more stably and firm- ly. First, the forward kinematics and inverse kinematics of the fingers and the hand are calculated. Then, the connection between the force exerting on the end effectors and the torque exerting on the joint is set up, laying the foundation for the following control. Finally, through the analysis and sim- ulation of the position, velocity and acceleration, the trajectory planning has a better performance.

MANIPULATION KINEMATICS ON DEXTEROUS HANDS CONSIDERING PURE ROLLING CONTACTS AS PASSIVE JOINTS

The manipulation and constraint equations are established by considering the pure rolling motion in a dexterous hand as two passive joints. According to mapping relation among the motion of the system, the differential kinematics and mobility are studied. The minimal structure for realizing the task motion of the object is obtained, and the conditions for dexterous manipulation are presented. Finally, some rolling manipulations are used as examples to demonstrate the applicability of approach proposed.

Optimal design and workspace analysis of tooth-arrangement three-fingered dexterous hand

Based on analysis of human hand grasp, the finger number and the kinematic pair pattern are decided. Aiming at the parameters of each finger, a multi-objective function for optimizing the structure of multi-fingered hand was proposed. Considering the peculiarity of tooth-arrangement and dexterous hand grasp, the constraints were established, and a satisfactory result was gained. Furthermore, the optimal results were analyzed, and a law of parameter optimal design was given. It is proved that this optimization method is effective to optimize the relation of each parameter and make it integrated optimum under each standard. At last, the practical workspace of this hand was analysed and simulated. And a new effective simulation method of workspace was proposed.

Design and control of integrated pneumatic dexterous robot finger

Based on flexible pneumatic actuator(FPA),bending joint and side-sway joint,a new kind of pneumatic dexterous robot finger was developed.The finger is equipped with one five-component force sensor and four contactless magnetic rotary encoders.Mechanical parts and FPAs are integrated,which reduces the overall size of the finger.Driven by FPA directly,the joint output torque is more accurate and the friction and vibration can be effectively reduced.An improved adaptive genetic algorithm(IAGA) was adopted to solve the inverse kinematics problem of the redundant finger.The statics of the finger was analyzed and the relation between fingertip force and joint torque was built.Finally,the finger force/position control principle was introduced.Tracking experiments of fingertip force/position were carried out.The experimental results show that the fingertip position tracking error is within ±1 mm and the fingertip force tracking error is within ±0.4 N.It is also concluded from the theoretical and experimental results that the finger can be controlled and it has a good application prospect.

An Adaptive Hand Exoskeleton for Teleoperation System

Teleoperation can assist people to complete various complex tasks in inaccessible or high-risk environments,in which a wearable hand exoskeleton is one of the key devices.Adequate adaptability would be available to enable the master hand exoskeleton to capture the motion of human fingers and reproduce the contact force between the slave hand and its object.This paper presents a novel finger exoskeleton based on the cascading four-link closed-loop kinematic chain.Each finger has an independent closed-loop kinematic chain,and the angle sensors are used to obtain the finger motion including the flexion/extension and the adduction/abduction.The cable tension is changed by the servo motor to transmit the contact force to the fingers in real time.Based on the finger exoskeleton,an adaptive hand exoskeleton is consequently developed.In addition,the hand exoskeleton is tested in a master-slave system.The experiment results show that the adaptive hand exoskeleton can be worn without any mechanical constraints,and the slave hand can follow the motions of each human finger.The accuracy and the real-time capability of the force reproduction are validated.The proposed adaptive hand exoskeleton can be employed as the master hand to remotely control the humanoid five-fingered dexterous slave hand,thus,enabling the teleoperation system to complete complex dexterous manipulation tasks.

HIT／DLR HandⅡ类人形五指灵巧手机构的研究

为了使灵巧手的外观和结构功能更加类人化,研制了新一代类人形机器人五指灵巧手——HIT/DLR HandⅡ.该灵巧手由一个独立的手掌和5个完全相同的具有4个关节3个自由度的模块化手指构成.机电集成的设计思想保证了所有驱动器,传动系统和电路系统都集成在手指和手掌的内部.钢丝耦合机构的采用,保证了手指末端关节在整个运动范围内都能够保证精确定1:1传动比.包装件同结构功能件融合的设计思想不但进一步缩减的灵巧手的外形尺寸,而且使灵巧手外形更加类人化.所有的创新型设计使灵巧手的手指外形尺寸仅是上一代手指的1/3.此外,为了提高灵巧手的多感知能力,重新设计的力/力拒传感器,位置传感器及温度传感器通巧妙的集成在手指的内部.试验表明,所设计的灵巧手不但达到了设计目标,也表现出了很强的抓握能力.

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1.5kg,手指的指尖输出力10N。

欠驱动灵巧手的优化设计及仿真分析

传统欠驱动机械手的运动空间相对固定、操作功能单一,对抓取物没有较强的自适应性,为此设计一种新的连杆式欠驱动灵巧手机构,并进行设计优化和仿真抓取实验。阐述了该灵巧手的整体机构设计及工作原理,其可实现包络和指尖两种抓取模式。根据手指的几何尺寸采用协同耦合方式设计手掌尺寸,利用可变手掌协同手指抓取,提高了灵巧手在抓取形状复杂和不同尺寸物体时的自适应性。基于虚功原理建立灵巧手单指各关节的接触力模型,针对抓取过程中存在的抓取力不足及抓取不稳等问题,使用NSGA-II优化算法对单指机构的杆长进行尺度综合。利用建立的虚拟样机进行仿真抓取实验,结果表明,该灵巧手具有较强的自适应性,能够稳定抓取多种形状和尺寸的物体。

可侧摆腱驱五指灵巧手的设计与仿真

为了实现五指灵巧手对多种物体稳定抓取的目的,针对灵巧手结构复杂、成本高等问题,提出了一种基于蜗轮蜗杆驱动的手指侧摆方案,设计了一种以腱绳作为传动方案的仿人型五指灵巧手,具有驱动简单、质量轻、成本低等优点;利用D-H法建立了灵巧手指的运动学模型;且利用MATLAB的机器人工具箱,分析了手指的工作空间;利用ADAMS软件创建五指灵巧手的虚拟模型,分析了此单腱欠驱动灵巧手设计的有效性和抓取可行性。

基于PSO算法优化模糊PID控制器的灵巧手抓取控制研究

随着仿生学的进展,机器人领域中五指灵巧手作为主要执行机构的重要性不断增强。然而,在抓取过程中,五指灵巧手常常面临内部作用复杂、速度缓慢和效率低等问题。为了应对这些挑战,该文提出了一种基于角度闭环模糊自适应控制算法。该算法采用模糊策略来推断灵巧手关节角度偏差与控制器参数之间的关系,并制定相应的模糊规则。通过实时调整控制器参数,该算法能够提高系统的稳定性和抓取效率。此外,通过建立ADAMS模型和相应的闭环控制系统,以提高实验过程的可视化程度。实验结果表明,通过采用粒子群算法(Particle Swarm Optimization Algorithm)优化模糊自适应PID算法并改进系统参数,相较于传统的PID算法,可以显著减少灵巧手在抓取过程中的关节抖动,并展现出更好的手指指尖接触力控制性能。

基于ADAMS的机器人灵巧手建模与仿真

为由于传统的末端夹持工具无法满足复杂应用场景,通过SolidWorks软件设计了一款仿人手的机械夹持末端,将机械手的三维模型导入到ADAMS软件中进行基础的仿真测试,通过简单的捏取动作捕捉其基本特性。仿真测试结果表明,在实验条件下机械手能够正常完成预定动作,为仿人手的五指灵巧手应用于实际生活提供参考。

基于腱绳驱动的仿人灵巧手

针对仿人灵巧手依赖复杂驱动传动机械结构和控制方法,以及缺乏灵活性、适应性的问题,结合对人手结构与功能的分析,设计了一种仿人灵巧手。从灵巧手的传动和结构两个方面出发,利用柔性腱绳在扭绞过程中的缩短效应作为灵巧手的驱动方案,并研究灵巧手在腱绳传动下的结构设计,通过耦合机构设计实现手指的灵巧抓持。对手指的运动学、静力学进行推导,完成手指工作空间计算。最后进行了不同尺寸物体的抓持试验。结果表明,所设计的仿人灵巧手可在设计范围内对典型形状物体完成稳定、可靠的抓持,并为后续灵巧手抓取控制打下基础。

Design and fabrication of a gecko-inspired surface for improving the grasping ability of a humanoid dexterous hand

Many studies have examined the design,fabrication and characteristics of gecko-inspired adhesives,but applied research on gecko-inspired surfaces in humanoid dexterous hands is relatively scarce.Here,a wedged slanted structure with a curved substrate suitable for humanoid dexterous fingers was designed and manufactured via ultraprecision machining and replica molding.The adhesion and friction properties of the wedged slanted structure show obvious anisotropic characteristics in the gripping and releasing directions,and the influence of structural parameters and motion parameters on the adhesion and friction was systematically studied.The humanoid dexterous fingers with gecko-inspired surfaces greatly increased the grasping force limit(increase to 4.02 times)based on the grasping of measuring cups with different volumes of water and improved the grasping stability based on the picking up of smooth steel balls of different diameters.This study shows that this process,based on ultraprecision machining and replica molding,is a green,high-efficiency,and low-cost method to fabricate large-area biomimetic surfaces that has potential applications in dexterous humanoid hands to improve grasping ability,stability and adaptability.

面向人机协作系统的上肢姿态精准识别算法研究

在基于姿态识别协同控制灵巧手机械臂的任务中,会出现身体部位相互遮挡以及非操作人员身体干扰的问题。因此本文提出了一种面向人机协作系统的上肢姿态精准识别算法,能够有效排除遮挡和干扰问题。该算法首先基于Finger-YOLOv4算法框选出人体上肢区域;其次通过稀疏性目标提取算法排除非操作人员身体干扰;然后在设计的双特征条件随机场网络中进行深度学习,解决遮挡导致的类内模糊问题,精准定位人体上肢的48个关键点坐标;最后,根据关键点坐标进行人体上肢的姿态预测,将人体上肢的姿态与灵巧手机械臂的姿态进行映射,完成人机协作。实验表明,本算法平均检测速度33 FPS,关键点平均检测精度75.2%,协同操作完成度98%。满足实际需求。

一种具有良好灵巧性和触觉估计的三指机械手

针对传统三指机械手存在灵巧性较低、抓取姿态偏少且绝大多数难以获得较完整触觉估计的弊端,设计了一种基于滑块-摇杆机构的三指机械手。滑块-摇杆机构用于实现中节指骨和远节指骨的耦合运动,具有指尖力随手指弯曲程度增加而增大的特点,有利于三指机械手的稳定抓取;提出与传统偏航-俯仰型不同的翻滚-俯仰型掌指关节结构,用于手指的屈伸与转动,可丰富三指机械手的抓取姿态,提高其灵巧性;三指机械手整体结构设计便于触觉传感器及角度传感器的安装及走线,通过建立运动学模型,可获得所有触觉力的详细空间分布(位姿)信息,实现三指机械手的良好触觉估计。抓取姿态及抓取力实验证明,三指机械手具备良好的抓取性能及较高的实用价值;触觉估计实验证明,三指机械手可为未来机械手的精确控制提供充分的触觉信息。

仿人灵巧手的稳定抓取方法研究综述

作为引领新一轮科技革命和产业变革的重要抓手,人形机器人通过集成具有类人抓取能力的仿人灵巧手,有望在工业生产、家庭服务、反恐排爆等不同应用场景中辅助或代替人类进行精细、复杂的作业。针对不同应用场景下的仿人灵巧手稳定抓取方法研究展开综述,梳理不同结构仿人灵巧手稳定抓取构型的实现形式,总结仿人灵巧手基于外部传感/本体传感的接触状态分析与估计方法,归纳仿人灵巧手在与物体发生全局相对运动/局部相对运动下的抓取状态检测与识别方法,给出常用的仿人灵巧手稳定抓取控制策略。分析仿人灵巧手在接触、抓取过程中上述方法的应用优势及不足,讨论软体材料、动态场景等因素影响下仿人灵巧手稳定抓取方法研究面临的挑战,并展望了其研究趋势及在人形机器人上的应用。

Anthropomorphic Control of a Dexterous Artificial Hand via Task Dependent Temporally Synchronized Synergies

Despite the recent influx of increasingly dexterous prostheses, there remains a lack of sufficiently intuitive control methods to fully utilize this dexterity. As a solution to this problem, a control framework is proposed which allows the control of an arbitrary number of Degrees of Freedom （DOF） through a single electromyogram （EMG） control input. Initially, the joint motions of nine test subjects were recorded while grasping and catching a cylinder. Inherent differences emerged depending upon whether the cylinder was grasped or caught. These data were used to form a distinct synergy for each task, described as the families of parametric functions of time that share a mutual time vector. These two Temporally Synchronized Synergies （TSS） were derived to reflect the task dependent control strategies adopted by the initial participants. These synergies were then mapped to a dexterous artificial hand that was subsequently controlled by two subjects with transradial amputations. The EMG signals from these subjects were used to replace the time vector shared by the synergies, enabling the subjects to perform both tasks with a dexterous artificial hand using only a single EMG input. After a ten minute training period, the subjects learned to use the dexterous artificial hand to grasp and catch the cylinder with 100.0% and 65.0% average success rates, respectively.

新型柔性三维力触觉传感器的设计与研究

对柔性三维力触觉传感器进行了研究和设计,详细分析了该器件的基本结构和材料选型,基于实验方式对器件的性能和功能进行了验证分析。根据验证的结果可知,该传感器具备了较高的灵敏度,其中,在x,y轴上可以达到1.8 V/N,而在z轴内则为3.1 V/N,验证该传感器的性能良好。在灵巧手中集成设计的传感器,进一步进行实验验证,结果表明:可以实现对水杯的自适应抓取控制,验证了该传感器的性能,可用于工业机器人设计等领域中。