不规则件优化排样的小生境遗传模拟退火算法

提出一种基于小生境遗传模拟退火算法求解不规则件排样问题的方法。该方法首先充分考虑不规则形状零件自身的形状特征,采用组合矩形包络算法将二维不规则零件的排样问题转化为矩形件的排样问题,克服了以往简单采用最小包络矩形代替零件排样存在空白区域,从而导致材料可能发生的利用率过低问题;然后利用遗传模拟退火算法及小生境技术相结合,寻找排样件在排样时的最优次序及各自的旋转角度;最后用"最低水平线与填充算法相结合"策略的启发式排样算法实现自动排样。实例表明了该算法的有效性和实用性。     

面向智能制造的不规则零件排样优化算法

以智能工厂应用场景为例,为提高广泛应用于智能制造领域的二维不规则件的排样性能,提出了基于启发式和蚁群的不规则件排样优化算法.首先提取不规则件的几何特征,对零件进行组合操作预处理,使两个或多个不规则零件组合为矩形件或近似矩形件并对其包络矩形,然后利用蚁群学习算法对预处理后的零件进行排样,确定零件排放的最佳位置,不断更新得到最优排样结果.仿真实验结果表明,综合考虑板材利用率以及耗时情况,所提算法取得了较好的结果,能够满足实际生产的需求.     

一种求解PCB合拼拼板的新算法

PCB合拼拼板问题是二维不规则零件排样标准问题的扩展,是一种新的优化拼板问题。提出了一种求解PCB合拼拼板的新算法,该方法运用一种启发式算法对所有PCB进行合拼选择,并采用二维不规则零件排样相关技术进行拼板并反馈结果,实现边搜索边排板,排板完再搜索的高效性,可行性合拼拼板结果。最后运用该优化算法对文献中的实际生产数据进行求解,合拼结果表明该算法是有效的。     

基于重心NFP的二维不规则形状排样算法

提出了一种基于重心NFP的二维不规则多边形排样算法，算法主要包括临界多边形计算和排样定位选优等内容。该算法以多边形来表示板材和待排零件，通过求解临界多边形NFP来得到多边形之间的所有靠接（排放）位置。为了在NFP中进一步得到优化的靠接位置，在NFP的基础上提出了重心NFP的概念，通过选择重心NFP中的最低重心位置来确定零件的排放位置。在零件的排样次序算法上，提出了顺序递归排样算法和遗传算法，以降低排样过程中形成的空腔所造成的浪费。该算法可处理板材和零件均为不规则形状的排样问题，允许零件在全角度范围内进行旋转，并可处理板材内部带孔洞或者边界形成空腔等特殊情况。     

碰靠定位算法在不规则件排样优化中的应用研究

基于不规则零件碰靠算法的思想,提出了最小静矩吻合碰靠定位方法。将碰靠定位的参考区域限定在入排零件当前排样高度最低的未排空间内,零件以不同入排角度进行正交靠接排放和定位,以零件定位后的静矩最小作为排样方案优劣的评估规则。在自动碰靠算法基础上,设计了交互排样中的点对点交互碰靠算法,实现零件以任意碰靠方向进行最优布局调整,为完善自动排样提供了有效的辅助作用。     

基于图形区域的同类零件自动优化排样算法实现

对于计算机的自动优化排样,提出了一种基于零件图形区域的动态定位算法,该算法用于某一类零件的单排或对头双排,既能排要效率,又能提高排样的自动化程度。     

冲裁件智能排样系统的研究

提出Hopfield人工神经网络与遗传算法相结合的算法,进行了智能排样系统的研究。该系统通过读入冲裁零件排样图形,自动计算出排样结果,并输出零件的优化排样图形。实例分析结果表明。该系统不但具有良好界面和人机交互功能,而且排样自动化程度高、提高了材料利用率。     

粒子群算法在不规则件排样优化中的应用

针对不规则件排样问题,提出一种应用粒子群算法优化求解的方法。首先以零件的入排交换序列和角度变异序列作为粒子运动速度构造粒子群算法,然后运用剩余矩形动态匹配算法实现解码和局部寻优,并结合不规则件的正交靠接算法实现自动排样。排样实例表明,该优化排样算法是有效的。     

智能算法的板材下料优化排样系统研究

为了降低产品制造成本,提高企业竞争力,提高板材的使用效率,以及更为合理的使用钢板,开发了基于智能算法的板材下料优化排样系统,采用了遗传算法,研究了适用于二维不规则零件的排样系统,实现了零件自动化排样。     

混合遗传算法在飞机钣金零件排样中的应用

针对飞机钣金二维不规则零件排样问题,将遗传算法与模拟退火算法相结合,提出一种混合遗传算法。该算法利用改进的最小包络矩形把不规则件转化成矩形件,在初始种群时提出一种既考虑排样高度,又考虑排样废料利用率的适应度函数,并引进浓度衡量个体之间的相似程度,为逃离局部最小值指明了方向。实例结果表明,该算法运用到飞机钣金排样系统中,在缩短排样时间和提高排样精度方面取得一定的效果。     

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...     

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.     

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。     

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...     

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。     

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。     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

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.     

RLS and LMS blind adaptive multi-user detection method and comparison in acoustic communication

RLS and LMS blind adaptive multi-user detection algorithm and multi-user detector was proposed to solve the problem of multi-user signal detection problem encountered in underwater acoustic communication networks.In simulation analysis,RLS and the LMS blind adaptive multi-user detector were designed and tested for synchronous and asynchronous multi-user communication process.The results of SIR comparison and MMSE comparison show that,both of the two methods can realize blind adaptive detection when any user change in multi-user communication,during this process,the training communication sequences are not needed.The RLS algorithm has about 5 dB higher in SIR compared with LMS algorithm,and the convergence velocity of RLS algorithm is also higher than LMS algorithm when the communication users change.RLS algorithm has better ability in multi-user detection than that of LMS algorithm,and it has great attraction and guiding significance for solving the problem of multiple access interference(MAI) in multi-user communication.     

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...