电动推杆驱动串联双铰链柔性机械手的状态分析

提出一种欠驱动柔性关节机械手,采用一个电动推杆驱动带有2个扭弹簧的串联双铰链机械手手指结构。介绍了该机械手结构和驱动原理,建立静态力学方程和几何平衡方程,通过Matlab软件的fsolve函数得出无刷直流电机输入电流与两个扭弹簧扭转角关系、输入电流与机械手手指张开大小的关系等,为串联双铰链柔性机械手抓取形状和尺寸变化、材质不同的特殊物体提供了理论依据。     

超欠驱动仿生机械手的机构设计与实验研究

利用多自由度差动驱动原理,设计了5自由度差动驱动系统用于驱动手指5个分支的运动.应用欠驱动原理,通过在各关节处设置弹簧,约束各分支关节的运动;同时手指关节之间用片簧连接实现铰链和恢复弹簧的两种功能,构成弹性铰.在对传动机构进行分析的基础上,设计了常开状态的仿生机械手,对仿生机械手进行三维造型和模型制作,并对其进行了抓取等实验研究.研究表明,设计的仿生机械手仅由一个原动力便可驱动手的15个关节差动运动,具有对抓取物体的自适应性.     

一种具备多种抓取模式的三指机械手

针对国内外高端灵巧手存在价格高、结构复杂的问题,从简化结构但又能满足较复杂抓取模式的角度考虑,设计了一种具备多种抓取模式的三指机械手。该机械手由3根同样的手指组成,每根手指有3个关节;使用钢丝绳耦合传动实现欠驱动,减少了驱动电动机数;为保证手指控制的灵活度,末端指尖单独由电动机驱动。采用D-H参数法建立手指运动学模型,完成正运动学求解。通过ADAMS软件对机械手进行运动学仿真,分析了三指机械手的运动特性及抓取力。根据包络抓取、精细抓取和普通夹取等几种抓取模式的需要布置了触觉传感器,对常见的目标物进行了抓取试验,验证了该机械手的实用性。三指机械手成本低、制造加工方便,对于难以获得昂贵灵巧手的研究机构和工厂具有实际应用价值。     

水下欠驱动机械手结构设计与仿真分析

面向水下机械手深海作业环境,研究设计了一种可用于水下环境的欠驱动机械手,机械手共有3个手指,每个手指有3个关节,是由连杆传动的欠驱动手指,欠驱动使手指抓取具有自适应性。分析了手指运动机理,研究设计了手指模块和整体结构,对手指进行了抓取静力学分析,在ADAMS软件中对机械手进行动力学仿真,验证了机械手结构的合理性与可行性。     

欠驱动手爪设计及接触力分析与仿真

针对现阶段自动化生产中末端执行器适应性较差的问题,设计了一种采用欠驱动机构的机械手爪。对欠驱动手爪的总体结构和存在的各个抓取构形进行了分析。基于虚功原理,将弹簧扭矩和被抓取目标重力纳入考虑范围,建立了较为精确的静力学模型,提出了接触力调节的方法。利用ADAMS对静力学模型和接触力调节方法进行了仿真验证,结果表明该欠驱动手爪抓取范围较大,理论计算与仿真结果误差较小,接触力调节方法切实有效。     

多模式抓取欠驱动手的机构设计与力学分析

针对机器人末端执行器机械手多功能化的需求,提出了一种多模式抓取欠驱动手.该机械手基于欠驱动理论,解决了传统复合欠驱动手存在的结构复杂、控制元件多、适应能力不强等缺点.介绍了多模式抓取欠驱动机械手的结构组成和运动过程,建立了欠驱动手的数学模型;根据几何关系对机械手进行运动分析与适应性分析,并求得机械手抓取的参数范围;在不同的抓取模式下,分别对机械手进行受力分析,利用虚功原理,计算出理论输出力.虚拟样机仿真实验表明,该机械手无需安装受力传感器及复杂的控制系统,可实现平夹和包络两种抓取模式,验证了设计的可行性.     

一种新型铝锭码垛机械手的研究设计

针对目前我国铝锭生产线中的码垛机械手的要求设计了一种新型关节式铝锭码垛机械手。该机械手采用气压驱动,并通过抓锭结构、夹锭结构、压锭结构实现铝锭的稳定抓取、搬运、码放等操作。并给出了动力学计算公式以及对气动系统等问题进行的分析与研究,试验结果表明,该机械手能实现生产中所需的动作要求。     

高适应性3指变位机械手爪的设计与研究

随着机器人在农业和物流等行业的广泛应用,抓取对象形状和体积呈多样化,对机器人的末端执行器即机械手爪的适应性提出更高要求。针对该问题,文中基于欠驱动的方式设计了一种具有高适应性功能的3指变位机械手爪。首先,建立3指机械手的三维模型,分析其平夹和包络抓取两种抓取模式;其次,对该结构进行力学分析包括弹簧的力学分析和手指的力学分析;最后,进行3指机械手样机加工研制和试验。试验结果表明：该机械手爪能够针对不同的物体实现稳定抓取,适应性高。     

双电机协同控制手指变位与转位的变掌机械手

针对现有欠驱动机械手存在的抓取范围不足的问题,提出一种基于曲柄滑块机构,连杆长度可变的并联机构变掌机械手。此机械手使用无驱动弹性手指,采用两个步进电机驱动,协同控制曲柄的转动角度和连杆的长度,从而实现抓取过程中手指指根的变位与转位,能够满足长方形、圆形等物体的抓取,对抓取对象的外形和尺寸具有良好的适应性。首先给出机械手结构,提出来了机械手的运动过程及抓取位势;分析了机械手对圆柱形物体的抓取过程及状态,研究其抓取特点;讨论机械手的抓取范围及适应性。     

基于力反馈数据手套控制的仿生机械手设计研究

仿生机械手具有与人手相似的外形,可代替人手完成高危工作。为了实现灵活抓取物体,根据人手结构的分析,采用腱驱动方式驱动手指关节。通过穿戴在手上的力反馈数据手套,实时控制机械手的运动;机械手上的压力传感器实时读取压力值,并传回数据手套,从而控制手套上的棘轮棘爪机构,实现力反馈。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.