基于自适应遗传算法的大型关重件车间布局优化

针对大型关重件生产车间的多行布局问题,建立了同时考虑物流费用与物流时间的多目标优化数学模型,运用了一种改进的自适应遗传算法,其交叉概率和变异概率可随群体的适应度自动改变,使算法避免陷入局部最优;加入精英保留策略,使每代中的最优个体都能够得到保留,避免交叉和变异操作遗失全局最优解。最后结合某船用曲轴车间实例,分别运用该算法和标准遗传算法对车间布局模型进行计算,通过数据和性能分析表明该算法有效的解决了遗传算法易陷入早熟及收敛速度慢的问题;优化后的车间物流费用及物流时间减少约35%,证明该方法在车间布局中的可行性和有效性。     

基于遗传算法的车间布局优化研究

针对某公司压力机装配车间设备布局问题,采用遗传算法进行优化设计。在其过程中首先建立数学模型,并设置约束条件、目标函数等因素。然后利用matlab软件将原车间布局作为初始种群,通过选择、交叉、变异等操作,运行成更合理的车间布局方案,优化方案证明了算法的实用性。     

基于虚拟现实的车间布局系统的研究

依据车间布局的最小物流费用原则,建立了布局优化的数学模型,并对该模型应用遗传算法进行求解.根据车间布局优化的特点,设计了混合编码的方法,并改进了选择算子、交叉算子和变异算子等遗传操作算子.最后给出了一个算法求解实例,并采用虚拟现实技术将计算结果形象地呈现出来.文中所提出的方法能够很好地解决车间设备布局问题.     

车间多行布局精准建模与多目标优化研究

基于车间布局总物料搬运成本最小和面积利用率最大的设计原则,同时考虑制造车间主干道、功能区横竖放置及自适应行距等因素,建立了生产车间多行直线布局的多目标优化精准数学模型,采用改进的多种群遗传算法(multiple population genetic algorithm, MPGA)进行求解。在求解过程中,采用移民算子联系种群,实现种群间的信息交换和协同进化,研究交叉和变异概率控制参数,以确保全局和局部搜索的精度。实例结果表明,该模型实用性强且求解算法稳定性好、收敛精度高。     

基于改进自适应遗传算法的柔性作业车间调度问题研究

为了克服遗传算法在解决柔性作业车间调度问题中收敛速度慢、易陷入局部最优的缺陷,根据柔性作业车间调度问题的特点,提出一种具有自适应交叉概率与变异概率的改进自适应遗传算法。将交叉概率与个体适应度值相关,将变异概率同时与个体适度值与进化代数相关,采用有效的编码、解码机制,引入精英保留策略。通过对两个基准问题进行仿真分析,验证了改进自适应遗传算法的有效性。     

车间多排设备布局问题的优化研究

在车间多排设备布局问题上往往存在限制条件多、设计方案不合理的情况。针对车间多排设备布局问题的特性,提出一种车间布局优化模型,并且利用遗传算法变异策略优势改进粒子群算法,使得设计方案更加合理。首先,将车间设备进行坐标化,建立了基于总物流成本最小的目标函数。经过综合分析,量化了各工序之间的物流关系。然后根据消防通道、设备占地与间距等非物流因素采用分级惩罚思想建立各种约束。此外,利用随机生存的初始种群,采用加入遗传算法的自适应变异策略的粒子群算法搜索最优车间布局。最后,通过一个案例研究了该模型的工作原理。与系统布置设计(Systematic Layout Planning, SLP)方法和遗传算法(Genetic Algorithm, GA)相比,该方法在解决多排设备布局问题效果更好。     

飞机结构件加工车间多层次式布局与优化研究

车间布局设计是一个具有非线性、NP-hard等特征的组合优化问题。结合飞机结构件生产多品种、小批量、短工序的特点,提出多层次式布局与优化策略,该策略从以下三层次进行:结合人机工程学,进行机床单元布局;根据机床数量以及型号进行功能区划分和功能区布局;以物流时间最短为目标进行总体布局,通过系统布置设计得出较优的初始解,利用遗传算法进行优化计算,得到最优布局方案。层次布局策略便于机床分区管理,减少直接布局的机床数量,更易获得令人满意的车间布局。最后,通过实例验证了多层次式布局与优化策略的有效性。     

基于差分进化与块结构邻域的作业车间调度优化

作业车间调度问题是一类非常重要的生产调度问题,具有广泛的工程应用背景.针对优化最大完成时间指标,研究通过交换或插入关键路径块结构中的工序产生可行解的方法,提出基于块结构的交换邻域和插入邻域.结合问题的结构特点和基本差分进化算法的原理,提出一种解决作业车间调度问题的离散差分进化算法.该算法采用基于操作的编码方式,设计了离散的变异算子和交叉算子,能够直接产生可行调度解.进而提出一种自适应的多邻域局部搜索算法,并将其嵌入离散差分进化算法中来改善优化质量;基于典型算例的仿真试验验证了所提算法的有效性和优越性.     

基于单级倒立摆的遗传神经网络控制研究

由于倒立摆是一个高阶次、非线性和自然不稳定系统,为了改善单级倒立摆的稳定性问题,提出一种改进遗传算法的RBF(径向基函数)神经网络控制方法.该方法以传统遗传算法为基础,通过对适应度值的自适应缩放、交叉率和变异率自适应调整等策略实现对RBF神经网络基函数参数和权值的优化.通过单级倒立摆仿真实验分析表明,虽然改进遗传算法的...     

基于改进遗传算法的PID参数优化在闪蒸罐压力控制中的应用

由于在加氢裂化过程中闪蒸罐压力控制存在非线性、大滞后等问题,运用常规比例-积分-微分(Proportion-IntegralDerivative,PID)控制效果较差,虽然传统遗传算法可以优化PID参数,提高控制精度,但是收敛速度慢,整定时间长,限制了其在闪蒸罐压力控制中的应用。针对以上问题,提出了一种通过改进遗传算法优化PID参数的新型方法,该方法以传统遗传算法为基础,通过对适应度值的自适应缩放、交叉率和变异率分别按Sigmoid函数和高斯分布函数自适应调整等策略来提高遗传算法的全局搜索能力和收敛速度,从而实现对PID控制参数的优化。仿真结果表明,用改进遗传算法优化后的闪蒸罐压力PID控制具有更好的自适应性和鲁棒性,使系统调节时间减少到86 s,超调量减少到0. 141 8%,有效地改善了系统的动、静态特性。     

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...     

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.     

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.     

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.     

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...