机器人室内路径规划算法的实用性研究

机器人研究领域中的一个关键分支即路径规划技术,本课题在机器人P3-DX实验平台的基础上,通过栅格化建模对室内的环境实现分块。4种路径规划〖CD2〗回字形路径规划、迂回式路径规划、启发式路径规划与包围式路径规划的可行性已经得到验证,为验证4种路径规划的实用性,在真实环境中将这4种路径规划算法进行了实验研究,通过软件将机器人行走后返回的数据绘制出相应的路线图,同时,根据各路径规划算法的路线图的不同重复率与覆盖率,找出效率较高的路径规划算法。     

基于双层A*算法的移动机器人路径规划

移动机器人导航控制理论和方法的研究,是决定智能移动机器人能否真正实现自主化、智能化的关键,一直以来也是机器人技术领域研究的重点和热点。A*算法作为一种比较成功的算法应用在了机器人的路径寻优和规划方面,但由于A*算法本身的计算特点决定,在栅格环境下A*算法规划出的移动机器人路径往往存在着折线多、转折次数多、累计转折角度大等问题。针对A*算法的缺点和不足,在其基础上,提出了一种双层A*算法,该算法将栅格地图分为高层栅格地图和低层栅格地图,对栅格地图进行了"局部合并地图"的构建,在算法中加入了栅格占据概率函数,通过低层与高层算法相结合得到最优路径。仿真结果表明在很大程度上解决了A*算法存在的问题,使移动机器人能够在复杂环境下应用该算法进行路径规划。     

基于生物激励神经网络的移动机器人遍历路径规划

针对移动机器人路径规划问题,利用栅格法对复杂环境进行建模。每个栅格当作一个神经元,整个空间就是神经网络组成的拓扑状态空间,然后采用生物激励神经网络方法对移动机器人进行路径规划,该方法不需要学习过程,运算简单、反应快捷,计算机储存量小,实用性强。仿真研究表明：该方法生成的路径是平滑的,连续的,能够准确的避开障碍物．实现了机器人的完全遍历路径规划,充分证明该方法的有效性与可行性。     

改进遗传算法在移动机器人路径规划中的应用研究

针对基本遗传算法解决移动机器人路径规划问题存在收敛速度慢等不足,对遗传算法进行了改进,提出了一种改进自适应遗传算法。根据进化过程中个体适应度值的大小自动调节交叉概率和变异概率,从而使算法能够跳出局部最优解,克服早熟的缺点。同时采用栅格法对机器人工作空间进行建模。对移动机器人路径规划进行仿真实验,对比结果表明:该改进的遗传算法是有效可行的,能够有效的提高机器人路径规划的质量。     

改进动态窗口法的阿克曼移动机器人局部路径规划器

局部路径规划是移动机器人的一项关键技术,它的品质密切关系到整个机器人系统的性能。动态窗口法是一种在机器人的速度空间内进行运动规划的自主避障算法。将该算法与阿克曼机器人相结合,提出了一个包含轨迹曲率相似度评价因子的阿克曼移动机器人局部路径规划算法。最后,在机器人操作系统(Robot Operating System,ROS)上对该新算法进行了"S"型路径导航仿真实验。实验结果表明,该算法能在已知栅格地图内实现阿克曼机器人的自主避障功能。     

动态环境下移动机器人路径规划的改进蚁群算法

研究动态环境下移动机器人路径规划问题,采用栅格法对机器人工作空间进行建模,在使用蚁群算法进行全局路径搜索过程中引入人工势场的概念,使蚂蚁对最优路径更加敏感;机器人针对动态环境中可能出现的不同类型障碍物分别执行不同的避障策略;同时提出一种最优路径预测模型用于预测在避障过程中是否出现新的最优路径。算法结合人工势场法和蚁群算法的特点,将全局路径规划与局部路径规划相融合以提高路径搜索的效率。仿真结果验证了该算法的有效性。     

一种移动机器人全局路径规划新方法

针对移动机器人全局路径规划优化问题,本文提出一种采用栅格法进行建模,以分层搜索为核心思想的新搜索方法,该方法在外层采用A*算法将复杂的图元模糊化以简化环境,内层则采用人工势场算法将具体的栅格还原以解模糊,具有一定的理论意义与应用前景。仿真实验表明,该方法能达到较好的路径规划效率和实时性。     

基于智能路径规划算法的移动机器人设计

介绍了一种基于智能路径规划算法的移动机器人。该机器人以TMS320LF2407A作为主控制芯片,控制机器人左右轮电机运转．驱动机器人按照预定路径行走。其设计算法首先采用了改进的栅格和Distbug的组合进行全局和局部路径规划。详细阐述了该算法的基本原理及采用该算法的移动机器人控制系统硬软件设计。最后,介绍了该移动机器人自学习路径跟踪PID算法。实践表明,采用该算法的移动机器人行走速度快,实时性强,稳定性好,控制精度高。     

解决路径规划局部极小问题的势场栅格法

路径规划作为移动机器人顺利完成作业任务的前提,成为了机器人控制领域的研究重点和热点问题。人工势场法以其简洁性和有效性在路径规划中普遍应用,然而由于移动机器人对周围环境信息感知的局限性,容易导致局部极小问题的出现。针对此问题,提出了解决路径规划局部极小问题的势场栅格法。首先对机器人的工作环境进行栅格划分,然后应用改进后的人工势场法为每个栅格赋予势场值,机器人通过搜索势场值的下降方向不断接近目标点,接着采用赋最大值法对局部极小区域的栅格重新赋值,降低搜索的盲目性,使机器人以最优路径到达目标地点。对相同环境下的传统算法与改进算法进行仿真实验对比,结果表明无论是在有、无极小区域,或是目标点在障碍物附近,改进后的算法均可以成功规划出路径,且有效解决了传统人工势场法所面临的局部极小问题。     

蚁群遗传算法在移动机器人路径规划中的综合应用研究

针对基本蚁群算法在机器人路径规划搜索初期盲目性大、效率低以及其搜索后期容易陷入局部最优等缺陷,把遗传算法引入到蚁群算法中,提出了基于蚁群遗传算法的移动机器人路径规划方案,在栅格环境下对移动机器人路径规划方案进行仿真测试,仿真结果表明该方案能减少蚁群算法搜索初期的盲目性、缩小最优路径的查找范围,提高搜索最优路径的效率。     

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.     

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....     

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。     

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.