一种新型汽车驾驶模拟平台的运动分析与仿真

针对并联驾驶模拟平台成本高、控制复杂等缺点,设计了一种基于串联机构的新型三自由度汽车驾驶模拟平台。用D-H法建立了平台的运动学模型,完成了平台运动学正逆解的计算与分析。用Inventor软件建立平台的三维模型,导入ADAMS软件获得平台的虚拟样机。对平台虚拟样机进行运动学仿真,验证了运动方程的正确性和平台的可行性。利用ADAMS软件和Matlab软件联合仿真,清晰直观地展现了座椅质心工作空间的边界。获得的仿真数据为后续物理样机的结构设计、运动控制提供了可靠依据。     

含防扭结构的三自由度并联平台运动分析与仿真

以三自由度并联机器人为原型,设计了一种含防扭臂结构的并联运动平台,探索其在汽车模拟驾驶器上的应用。运用Inventor软件建立并联运动平台虚拟样机,使用ADAMS软件对平台进行运动分析和仿真,完成了平台在复合运动下的运动学正、逆解分析和动力学分析,得出平台的运动特性,对比分析了防扭臂结构对平台动力学性能的影响,为平台结构设计和运动控制提供了实用依据。物理样机试验表明,该并联平台能够准确模拟汽车驾驶过程和运动状态,成本低廉,响应速度快,运动精度较高,有较大的应用价值。     

沉船同步提升升沉补偿试验平台设计及联合仿真

以“畅通轮”尾端打捞为例,提出了沉船同步提升液压升沉补偿试验平台的结构,搭建了模拟沉船同步提升升沉补偿试验平台;针对其中的二自由度升沉补偿平台,对其进行了运动学反解,搭建了基于运动学控制的Simulink模型;结合阀控缸伺服控制系统实现了二自由度平台对波浪运动的模拟,并搭建了整个运动控制及升沉补偿控制系统的模型;通过ADAMS与MATLAB的联合仿真,验证了该二自由度平台升沉补偿控制系统的运动控制能力和动态响应能力,并对比补偿前后的升沉平台位移,证明了该系统良好的补偿特性。     

一种六自由度海浪模拟并联平台的零点标定与性能评估

针对并联机器人中存在的运动精度欠缺的问题,对一种用于海浪模拟的六自由度并联平台进行了零点标定与性能评估。确立了并联平台的运动控制模型,通过齐次坐标方法建立了该并联平台的运动学反解,并且在运动学反解的基础上采用边界搜索法确定了平台定姿态时的工作空间。采用"PC机+运动控制卡"的控制模式对该平台进行了运动控制系统的设计,实现了并联平台的运动控制。首先运用矢量推导法建立了平台的零点误差模型,然后借助于激光跟踪仪对平台进行了零点标定,提高了平台的运动性能。最后针对特定的海浪谱,利用该平台对其进行了模拟实验,并根据实验结果对平台的跟踪性能进行了分析。研究结果表明,经过零点标定后的并联平台能够很好地对海浪进行跟踪模拟。     

混联四自由度汽车驾驶模拟平台的控制系统设计

结合串联机构和并联机构的优点,设计了一种串并联结合的混联四自由度汽车驾驶模拟平台。选择平台动力源,对控制系统硬件进行了设计。编写基于C++语言的控制软件,实现了各自由度的运动控制及回原点功能。以平台并联机构左侧电机为例,对伺服电机各参数进行了计算,优选合理的型号。对平台样机进行测试实验,分析了测试结果,为后期平台优化提供参考。     

司步带传动周转轮系机器鱼的设计与验证

介绍了一种用于拖曳试验的多关节机器鱼试验平台,用以研究鱼类尾鳍游动机制,提供功耗可测,且能够精确拟合亚绣科鱼类运动曲线的多关节机器鱼。根据生物学鳕鱼外形观测数据,同时采用伺服电机驱动同步带串联周转轮系传动的方式,使仿生机器鳕鱼在形态学和运动学上最大程度复现自然界鱼类游动方式。介绍了平台的机械结构及运动控制的实现,同时利用虚拟样机技术对机器鱼设计方案进行运动学验证以及动力学分析。结果表明机构设计合理,能够满足设计需求。     

混联四自由度汽车驾驶模拟平台的运动仿真与研究

综合串联机构和并联机构的特点,设计了一种串并联结合的四自由度混联运动平台,并应用于汽车驾驶模拟器。运用Inventor软件建立了三维模型,并导入Adams获得虚拟样机。通过运动仿真验证了平台的可行性,分析了汽车的各种行驶状态,针对不同的行驶状态对平台各个部分进行运动学仿真,验证了平台的功能性,测试了平台对汽车驾驶状态模拟的运动性能。通过动力学仿真分析了平台的动力学性能,为平台结构设计与优化提供了理论依据。     

6-SPSR驾驶模拟器平台设计及机构理论分析

提出一种可连续转弯的6-SPSR驾驶模拟器平台机构的设计,详细介绍机构的组成及工作原理,并对机构进行了理论分析。该平台在传统的Stewart模拟驾驶器平台机构的基础上,增加了可以围绕Z轴无限旋转的上平台,有效地提高了绕Z轴旋转的回转行程,弥补了经典的Stewart模拟驾驶器平台机构不能模拟车辆大角度转弯的缺陷,增加了驾驶模拟器平台的工作空间,从而有效地提高模拟的真实性,且控制算法也比较简单。     

基于虚拟交互的虚拟挖掘机操作系统研究

针对挖掘机驾驶培训困难的窘境,开发了一套基于虚拟交互的虚拟挖掘机操作系统。该系统以Stewart平台为运动平台,结合VR技术,通过人操作一对手柄控制虚拟挖掘机的行走和工作,以模拟真实挖掘机。建立了Stewart平台的运动学反解模型并应用洗出算法,运动平台可以良好地模拟挖掘机前进、后退、转向、倾斜等状态。邀请了多位志愿者操作本系统并模拟现实挖掘任务,工作效率可提升约26%,表明该系统可为挖掘机驾驶训练问题提供新思路。     

基于气动人工肌肉的六自由度运动平台

实现六自由度机构准确、稳定运动控制的关键在于执行元件的控制特性以及动力学模型的准确表达。在分析一般六自由度平台特性的基础上,建立了气动人工肌肉双三角六自由度并联运动平台,运用Matlab进行运动学分析,生成机构运动空间。对所建模型进行运动模拟,根据仿真计算数据得到气动人工肌肉的运动特性,进而提出控制方法。     

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.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.