空间多机器人协同运动规划研究

面向空间在轨装配任务提出基于优先级的多机器人协同运动规划方法。多机器人系统包括一个7自由度操作机器人和一个13自由度超冗余照明机器人。采用两种规划方法规划高优先级的操作机器人,即关节空间点到点的离线路径规划和基于伪逆的笛卡尔空间在线运动规划。针对低优先级的超冗余照明机器人,将操作机器人视为已知障碍,采用基于A~*算法和末端轨迹跟随的可重构运动规划方法,将运动规划分解为末端路径规划和机器人各关节对轨迹的跟随问题,并验证算法的可重构性。采用具有特定运动学形式的机器人模型进行仿真试验,仿真结果表明,提出的各个机器人的运动规划方法均能有效满足任务需求,且照明机器人的运动规划算法具有可重构性,多机器人系统基于优先级的协同策略能够满足空间在轨装配任务需求。     

基于VisMockup的装配装置仿真与分析

利用VisMockup对建立的集成装配装置数字样机模型进行了装配仿真与分析。介绍了集成装配装置的结构与功能,根据经验初步规划了产品装配顺序,分析了利用装置进行产品装配的路径规划问题,介绍了基于拆卸的产品装配仿真方法,在VisMockup中应用该方法实现了基于装置的产品装配仿真;针对集成装配装置仿真分析的实际需要,开展了角度与距离的测量以及干涉检查分析。通过装配仿真与分析,提前解决了装置的主要装配问题,确定了相关运动参数的数值,直观地验证了操作空间、运动功能以及装配顺序的正确性,为实物样机的快速顺利开发奠定了基础。     

面向协同装配规划的装配单元规划方法

作为复杂产品装配规划的有效求解策略,协同装配规划将复杂产品的装配规划结构按照装配要求分解为简单的子装配规划结构,子装配规划结构的最优或次优装配序列采用成熟的装配规划方法求解,通过装配序列合并得到产品的整体装配序列。协同装配规划所要解决的首要问题是装配规划结构分解,针对这个问题,提出装配单元规划方法。首先从产品可装配性的角度分析了影响装配单元规划的装配设计和装配工艺约束,并对归类的部分装配约束进行量化;进而基于模糊层次分析法生成装配单元决策图,采用最小生成树算法生成候选装配单元。同时,建立装配关系干涉矩阵对候选装配单元进一步验证,生成装配过程中互不干涉的装配单元。以一款电动机装配体为例验证提出的方法,结果表明该方法是一种求解装配规划结构分解问题的有效方法。     

狭窄空间内复杂产品的装配路径规划研究

因为复杂产品的内部空间紧凑,为其规划可行的装配路径困难,所以提出一种基于快速搜索随机树的改进方法,以提高狭窄空间内复杂产品装配路径规划的成功率与效率。该方法以待扩展树节点为中心离散化局部空间,并为路径树的扩展提供多种备选位姿,再根据装配运动的难易程度,提出两种运动策略及对应的评价指标,引导局部路径的扩展。仿真结果表明,此方法在装配路径搜索成功率和效率方面均有提高。     

白车身装焊单元点焊机器人路径规划研究

轿车白车身装焊单元,常采用多机器人同时焊接,设备多、机器人工作空间环境复杂,依靠经验方法的路径规划工作量大且难以优化。通过对装焊单元进行分析,在采用商品化的建模与仿真软件对装焊单元进行建模的基础上设计了Probabilistic Roadmap算法自动规划点焊机器人的运动路径。通过对一单机器人装焊单元进行路径规划与仿真验证说明了规划方法的有效性。     

基于多视觉传感器融合的装配过程质量移动智能检测技术研究

针对航空航天领域大尺寸复杂产品装配过程质量检测过程中检测项目类型多、空间跨度大以及检测环境复杂等问题,提出一种基于多视觉传感器融合的装配过程质量移动智能检测框架。该框架以移动机器人为柔性运动载体,以多视觉传感器融合形成检测单元,可实现复杂产品装配过程质量的自动化、智能化检测。重点分析了基于模型驱动的视点与站位智能规划、基于情境感知的移动机器人自适应数据采集、多源数据融合与装配过程质量综合评定等关键技术,并通过实例验证了所提框架的合理性与有效性。     

基于VRML的机械产品虚拟装配技术研究

简要介绍了VRML语言定义、特点,阐述了机械零部件虚拟建模方法。对虚拟装配流程进行分析,并对产品装/拆运动的表示形式、虚拟装配路径规划及逻辑控制、虚拟装配过程中的碰撞检测方法等关键技术进行了研究,提出了产品装/拆运动12元组表示形式。最后,通过对机械产品交互式虚拟装配进行实例仿真,验证了该技术的可行性和合理性。     

基于混合算法的反射面天线面板装配序列规划

为了改善反射面天线面板的装配变形,从装配工艺入手,基于蚁群算法和遗传算法,结合传统的天线反射面装配方法,提出一种天线装配序列规划的混合算法。该算法利用蚁群算法快速得到初始种群,随后使用遗传算法对初始种群进行优化,根据所得优化解生成蚁群算法中路径上的信息素,通过加速蚁群算法最优解信息的积累来更快地得到最优解;同时,建立反射面装配的有限元仿真模型,利用该模型及时对得到的最优解(即装配序列)进行面向装配过程的面板装配变形动态仿真,将仿真结果返回算法中,进一步校正算法并得到最优解。以某工程抛物面天线的面板装配为例,验证了所提混合算法的正确性。     

虚拟装配环境下运动副自动识别方法

为有效地减少在装配仿真完成后进行机构运动仿真的前处理工作量,提高机构运动仿真的智能化程度,提出了一种在虚拟装配环境下面向运动仿真的机构运动副自动识别方法。通过提取虚拟装配环境下零部件间的装配约束信息,计算两个相连接零部件间所有约束的约束度,并利用计算所得的约束度自动映射出运动仿真机构中相应的运动副,为机构运动仿真中建立机构信息模型提供了基础信息。结合自主研发的原型系统虚拟装配工艺规划软件,给出了基于虚拟装配系统实现运动仿真的底层数据结构、机构模型的数据结构、信息传递过程和算法实现流程,并通过具体实例验证了方法的有效性。     

基于坐标变换的装配过程仿真视角优化方法

为了提高装配过程仿真的可读性和展示效果,提出了基于坐标变换的装配过程仿真视角优化方法。根据装配过程仿真的特点,给出了仿真视角的评价准则。研究了三维图形的坐标变换原理,通过包含装配路径和视角评价准则信息的视角变换矩阵,实现了装配仿真过程中视角坐标的变换。建立了基于视角变换的装配过程仿真优化流程,并讨论了仿真运动的速度和加速度对装配仿真展示结果的影响。基于在DELMIA DPM平台开发了视角调整功能,以飞机翼盒装配过程仿真优化为例,验证了所提方法的有效性。     

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...     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

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.     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

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....     

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.