4-UPS-CPC并联机构运动学分析

并联机构的运动学分析是并联机构研究的重要对象之一,是进行优化分析的重要依据。目前,国内外许多知名学者通过理论求解和软件仿真分析对并联机构进行了多方面的研究。以4-UPS-CPC并联机构为研究对象,建立机构模型和数学模型,进行了位置、速度及加速度分析,建立了机构输入输出的速度、加速度映射方程。在建立机构运动学模型基础上,用数学编程软件Matlab对机构进行了运动学数值仿真分析;基于动力学仿真软件Recur Dyn,实现了4-UPS-CPC并联机构的运动学仿真分析;利用Recur Dyn仿真结果对理论数值仿真的正解、逆解进行了验证。研究结果表明了运动学理论求解的正确性和仿真验证的可行性。     

夹钳机构的优化设计

在Pro/E环境下对初步设计的夹钳机构进行建模、装配及运动学仿真分析,发现模型运动学特性较差。为改善机构的运动学特性,将模型通过M echan ism/Pro接口程序导入ADAMS中进行优化设计,得到了改进机构运动特性的方法。在Pro/E下改进机构模型并再次进行运动学仿真,验证了改进结果的合理性。最后,通过平面几何知识对改进方法的合理性进行了证明。仿真结果表明,利用Pro/E和ADAMS联合仿真的方法可以为机械系统结构的优化设计提供一条有效途径。     

3-(P-)RS并联机构主轴的运动学研究与仿真

建立了3-PRS并联机构主轴的结构模型，通过运动学分析导出其运动学模型，并讨论了运用OpenGL图形库对主轴进行几何建模和运动学仿真。     

空间弱撞击对接机构对接过程运动学分析

以空间弱撞击对接机构（LIDS ）对接过程为研究对象,通过运用Pro/ENGINEER软件建立机构的三维模型,采用矢量方法建立运动学模型,对其位置和姿态进行了分析。运用Newton -Raphson迭代法对空间弱撞击对接机构进行了位置正解分析,表明该方法可以迅速求解。以对接机构的三维模型和运动学模型为基础,通过MATLAB和ADAMS软件进行联合仿真分析,得到了满足设计要求的运动轨迹曲线,从而验证了运动学模型。对弱撞击对接机构进行了动力学仿真,得到了机构传力构件的最大受力情况。     

ADAMS在并联机构运动学分析中的应用

针对并联机构的运动学分析计算,以3-UPS/UP型并联机构为例,介绍了应用动力学仿真分析软件ADAMS对其进行运动学仿真的方法与步骤。采用三维CAD软件Inventor建立了几何模型,以Parasolid格式导入ADAMS环境,对几何模型施加约束与激励,建立了并联机构的虚拟样机模型。并对模型进行了逆向与正向运动学仿真,快速准确地求得了并联机构的运动学反解与正解,大大简化了计算过程,为并联机构的运动学分析及机构设计提供了借鉴。     

基于ADAMS对下摆式递纸机构的动力学研究

对现有平版印刷机的下摆式递纸机构进行动力学研究并进行了重新设计.通过三维软件建立了递纸机构仿真模型.利用动力学分析软件ADAMS的测量输出和仿真分析功能,对它进行了运动学分析和仿真,并与原平版印刷机的递纸机构进行比较.仿真结果表明重新设计的递纸机构运行平稳,冲击力更小,符合设计要求.     

3-■RS并联机构主轴的运动学研究与仿真

建立了3-■RS并联机构主轴的结构模型,通过运动学分析导出其运动学模型,并讨论了运用OpenGL图形库对主轴进行几何建模和运动学仿真。     

基于Pro/e的送瓶机构的改进与运动仿真

介绍和分析了一种新的洗瓶机的送瓶机构,同时利用Pro/e对机构进行了建模和运动学仿真,通过对仿真结果的分析,提高了机构设计的准确性,为洗瓶机传动系统的优化设计提供了研究基础.     

基于ADAMS的一种新型六自由度并联机构的参数分析与仿真

通过ADAMS虚拟样机的试验和测试,可以在研究机构性能的同时发现设计中存在的问题并提出改进方法.为了充分阐述3-PRPS并联机构的运动学本质特性,利用线几何的有效方法对机构模型运动学进行了分析,求解了逆运动学关系,并应用ADAMS软件进行运动学仿真分析.其中通过定义已经建立的实体模型参数变量,合理规划选取动平台的运动轨...     

一自由度腿式行走机构的研究与设计

设计了一种一自由度腿式行走机构,机构由平面四杆机构和放大机构组成。首先基于契贝谢夫平面四杆机构特点,利用解析法,建立相应数学模型,得出运动学方程。其次利用Adams对行走轨迹进行仿真分析,讨论了连杆长度对运动轨迹的影响,并进行了运动学仿真研究。最后,通过系统仿真和搭建原型,验证了方案的正确性及机构设计的合理性。该机构的设计为开发新型的低功耗、低成本、易控制的腿式机器人提供设计了依据,实用可行。     

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.