遗传算法在行为建模路径规划中的应用

针对虚拟概念设计中零部件实体行为建模的路径规划问题,使用了遗传算法的规划策略实现实时动态避障,多个零部件实体装配时移动的位置和方向由智能Agent互通消息获得。同时本文对编码和适应度函数进行了研究,使它加速遗传算法的执行以便于实时控制,所提出的算法通过计算机仿真实验表明该方法具有良好的行为建模动态路径规划能力。     

融合改进A^(∗)算法与动态窗口法的机器人避障研究北大核心CSCD

针对机器人在全局未知环境的路径规划中无法进行实时动态避障的问题,提出一种将改进的A^(*)算法与动态窗口法融合的机器人避障方法。首先将传统A^(*)算法3×3搜索领域扩展至5×5搜索领域,并将16个搜索方向进行取舍至9个,同时优化启发函数,通过优化时间复杂度来提升A^(*)算法搜索效率;然后进行冗余节点移除操作,剔除机器人路径中的多余拐点和共线的点;改进后的A^(*)算法较传统A^(*)算法平均减少了65.805%的路径规划时间和4.967%的路径长度。最后将改进的A^(*)算法与动态窗口算法进行结合,使得机器人具有动态避障能力,且保证机器人在局部避障的过程中得到全局路径规划的最优解。     

基于深度强化学习的工业机器人避障路径规划方法

常规方法定义机器人避障奖赏函数时,仅在机器人到达目标位置后给出奖励,避障奖励稀疏,导致避障路径规划时间和长度较长、规划成功率较低。提出基于深度强化学习的工业机器人避障路径规划方法。利用传感器,探测机器人与障碍物和目标点之间的距离方位,构成状态空间,定义机器人避障决策奖赏函数,包括机器人与目标点的方位奖赏、距离奖赏、到达奖赏、每个避障动作奖赏,将状态空间信息输入神经网络,通过深度强化学习,输出下一时刻奖赏值最大的避障动作,形成最优避障路径。选择工厂厂房作为测试环境,改变障碍物数量和位置,布置工业机器人移动的简单场景和复杂场景,实验结果表明,设计方法减少了避障路径规划时间和长度,提高了规划成功率。     

基于改进 A∗ 算法与动态窗口法融合的 机器人随机避障方法研究

针对机器人在存在随机障碍物环境中采用A~*算法规划路径会出现碰撞或路径规划失败的问题,提出了一种将改进A~*算法与动态窗口法相融合的机器人随机避障方法。在改进A~*算法中,首先优化了搜索点选取策略和评价函数,提高了A~*算法的搜索效率;然后提出冗余点删除策略,剔除路径中的冗余节点,并在每两个相邻节点间采用动态窗口法进行局部规划,确保在全局最优路径基础之上,实时随机避障,使机器人顺利到达目标点。实验结果表明,改进A~*算法较传统A~*算法平均可减少4.39%的路径长度和65.56%的计算时长,融合动态窗口法后,能在全局路径基础上修正局部路径,实现随机避障,验证了该算法的有效性。     

未知环境下移动机器人实时模糊路径规划

针对机器人在未知环境下避障的要求,设计了一个结合目标点位置信息和局部障碍物信息的评价函数实时导航算法,使机器人可以在无碰撞的情况下较快地到达目标点。该算法以二维激光雷达作为探测环境的主要传感器,采用基于行为的控制策略及模糊控制器技术,通过添加自由出口提高其路径搜寻的效率,最后为了验证此模糊路径规划方法进行了仿真实验。仿真实验结果表明,该算法具有良好的效果,机器人可以有效避障,且轨迹平滑、实时性好。     

基于时间栅格法和最优搜索的电网巡检机器人避障路径规划方法

针对电网巡检机器人存在避障能力低下和路径规划不合理的问题,研究基于时间栅格法和最优搜索的电网巡检机器人避障路径规划方法.利用时间栅格法标识工作空间内障碍物,构建机器人电网巡检环境信息,通过最优搜索避障路径算法,全局规划机器人到达目标点的路径,结合改进势场法,通过调整斥力和引力势函数,计算合力实现机器人的局部避障及避障路径规划,形成全局和局部相结合的避障方法.试验结果表明,躲避静态障碍物和动态障碍物的平均躲避成功率分别为 ９８．３７％ 和 ９６． １２％ ,避障路径规划平均耗时为 １.５６ s ,具备快速、高效、精准的避障及路径规划能力,可提升机器人的动静态障碍物避障能力和路径规划效率.     

基于改进遗传算法的室内移动机器人路径规划

将一种改进的遗传算法应用到室内移动机器人的路径规划中。能够克服机器人运动路径穿越障碍物,算法收敛速度慢,容易陷入局部最优等缺点。根据环境先验知识从种群数目筛选、适应度函数的确定、遗传操作等方面进行了改进,加快了算法的搜索进程和演化效率。提出了一种将环境中大障碍物分割并多圆化处理的方法,并根据障碍物与机器人每步运动轨迹间的位置关系来设计遗传算法的适应度函数,扩充了可行区域并有效避免机器人和障碍物发生碰撞。应用此算法可以获得移动机器人从起点到终点的全局最优路径,在MATLAB软件中仿真得到的结果证明,改进的遗传算法搜索质量高、进化和收敛速度快,得到的最优路径能够有效指导移动机器人完成室内的避障移动任务。     

遗传算法在自主移动机器人局部路径规划中的应用

针对自主移动机器人的导航,为便于路径的规划,使用了遗传算法的轨迹规划策略实现实时动态避障,移动机器人和障碍物的位置和方向可由视觉系统检测。着重于应用的编码技术和选择适应度函数来加速遗传算法的执行以便用于实时控制,所提出的算法的效率由实验验证。     

基于通用运动学模型的移动机器人避障路径规划

介绍了移动机器人二轮差动机构通用运动学模型的建立、避障行为决策、避障运动控制等,提出了一种足球机器人避障路径规划方法.该方法简化了机器人避障的步骤,提高了机器人避障的灵活性和鲁棒性.仿真试验证明这种方法是可行而有效的.     

沿全局最优路径滚动避障的车间机器人导航研究

为了减少机器人在车间工作时的路径长度、提高行驶安全性,提出了全局规划和局部滚动避障相结合的机器人导航方法。对车间静态环境进行全局路径规划,在传统蚁群算法基础上,在转移概率中引入节点被访问次数作为新启发因子、同时引进随机选择策略和"回退-惩罚"策略,从而提出了基于改进蚁群算法的全局路径规划方法。对车间动态环境进行局部滚动预测避障,分确定和不确定运动提出了碰撞预测和碰撞避免策略,实现了沿全局最优路径滚动避障行驶。经仿真验证,改进蚁群算法规划出的路径比传统方法缩短了42.3%;在车间动态环境下,机器人使用滚动预测避障策略可以沿着最优路径安全到达目标点,实现了机器人在车间动态环境下安全导航。     

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.