应用混沌粒子群算法求解工程优化问题

针对工程优化设计问题,提出了基于混沌粒子群算法的工程约束优化问题求解方法.CPSO算法利用混沌搜索的全局遍历性、随机性和规律性等特点,引导粒子在全局范围内搜索,从而克服了传统粒子群算法早熟收敛的缺点.该算法以种群适应度方差作为粒子群优化算法早熟收敛的判据,并用惩罚函数法处理违法约束的粒子,当基本粒子群算法陷入早熟时,随机选择粒子群中的部分粒子实施混沌搜索,直至满足迭代收敛条件为止.CPSO算法能提高种群的多样性和粒子搜索的遍历性,从而有效提高了PSO算法的收敛速度和精度.两个工程约束优化实例的求解结果表明,该算法的优化结果最好,收敛速度也比较快.     

基于Tent映射的混沌粒子群优化算法及其应用

针对基本粒子群优化算法在迭代后期易陷入局部最优而出现早熟收敛的现象,基于混沌搜索的全局遍历性、随机性和规律性的特点,以粒子群群体适应度方差作为粒子群优化算法早熟收敛的判据,将Tent映射作为混沌搜索引入到基本粒子群算法中,对以一定概率随机选择的粒子群中的部分粒子实施混沌搜索,利用混沌特性提高种群的多样性和粒子搜索的遍历性,从而使粒子获得持续搜索的能力,提高了粒子群优化算法的全局搜索能力和抗早熟收敛性能.几个典型测试函数的仿真实验和应用实例均证明了该算法的可行性.     

混合优化算法在氧化铝生产中物料平衡计算上的应用

通过分析传统的单一优化算法所存在的优点与不足,成功将粒子群算法、混沌优化以及单纯形法3种优化算法有机结合起来,提出一种基于混沌-单纯形法的混合粒子群协同优化算法,加强粒子群的局部寻优效率和全局寻优性能,以提高搜索速度和成功率.Benchmark 函数仿真以及氧化铝生产中拜耳法物料平衡计算的最终结果表明:新算法不仅在稳定性和收敛性上优于传统粒子群算法和相应的改进粒子群优化算法,且具有较高的收敛速度和全局收敛能力,同时也是进行物料平衡计算的一种有效的方法.     

基于拆卸Petri网和混沌粒子群的拆卸序列规划

为解决燃气涡轮发电机组虚拟拆装训练中拆卸序列规划问题,提出了基于拆卸Petri网和混沌粒子群优化算法的拆卸序列规划方法。在基本Petri网的基础上进行拓展,引入了时间元素,构建了拆卸Petri网模型;针对粒子群优化算法容易陷入局部极值的不足,将混沌寻优方法嵌入到粒子群优化算法中,结合早熟评判标准,提高粒子群算法全局寻优能力。运用上述方法,以最短时间为目标,对分配机匣的完全拆卸序列进行仿真实验,得到了符合实际操作规律,可行有效的拆卸序列。     

一种航空发动机性能衰退预测的优化算法

针对航空发动机性能衰退预测问题,采用基于过程神经网络的优化算法来对发动机的燃气温度裕度(EGTM)进行预测。为克服过程神经网络学习速度慢的缺点,提出一种基于Tent映射的混沌粒子群优化算法对网络进行训练,建立预测模型。采用某航空公司的EGTM监测数据进行验证,分析结果表明,基于Tent映射的混沌粒子群优化算法具有较高的收敛速度和预测精度,可为航空发动机视情维修决策提供支持。     

基于混沌序列的起重机箱形主梁粒子群优化

为了解决起重机箱形主梁优化设计中的多变量、多约束问题,提出了一种新的基于混沌序列的粒子群优化算法。利用混沌变量的遍历性和随机性,通过Logistic映射生成初始粒子群位置。根据平均粒距描述种群的多样性,通过混沌扰动对早熟个体进行局部搜索,从而跳出局部极小点。起重机箱形主梁优化试验结果表明,新混沌粒子群算法具有收敛速度快,优化精度高的优点。     

混沌w的简化粒子群算法在机械设计中的应用

利用混沌序列的内在随机性、遍历性和规则性,提出了一种混沌惯性权重的简化粒子群优化算法.将该算法应用于机械设计,结果表明新算法具有更快的收敛速度和更强的全局寻优能力.     

粒子群优化的神经网络在故障诊断中的应用

为提高齿轮箱故障诊断性能，建立了以齿轮箱振动信号的时频域特征为输入，以齿轮箱的主要故障形式为输出的神经网络。采用粒子群优化算法代替反向传播算法来训练神经网络的权重和阈值，利用训练后的神经网络对齿轮箱进行了故障诊断，并比较了基于粒子群优化算法与BP算法的诊断结果。结论是基于粒子群优化算法神经网络具有较好训练性能，收敛速度快，迭代步数少，诊断精度高，具有良好的故障识别率。     

基于改进粒子群算法的复合材料机翼结构布局优化设计

采用粒子群算法对复合材料机翼结构进行布局优化求解.针对粒子群算法的早熟收敛现象,采用了两种改进措施:根据粒子的浓度变异粒子以增加粒子种群多样性;将变尺度混沌优化方法结合到粒子群算法中用以变异搜索最优粒子.算例结果表明,文中所提优化方法是可行有效的.     

粒子群优化人工神经网络在高速铣削力建模中的应用

将粒子群优化人工神经网络理论应用于高速铣削力的建模研究中.采用粒子群算法与反向传播算法相结合的方法,对反向传播神经网络模型进行优化.用粒子群算法训练网络参数,直到误差趋于一稳定值,然后用优化的权值进行反向传播算法运算,以实现高速铣削力的预测.充分发挥了粒子群算法的全局寻优能力和反向传播算法的局部搜索优势.仿真结果表明,与其他几种反向传播算法相比较,粒子群算法与反向传播算法的学习算法训练的神经网络,不仅训练时间明显缩短,而且其预报精度也得到了较大的提高,能够有效地建立铣削力模型,并对铣削力进行准确的预测.     

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...     

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。     

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。     

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.     

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.     

Fifth International Summer School on Screw-Theory Based Methods in Robotics

正3-11 September,2014University of Bologna,Bologna,Italy www.summerscrews.org summerscrews2014.ing.unibo.it SUMMER 20SCREWS 14In 2014,our screw-theory school comes to the world's oldest university.In early September,Summer Screws'14 will gather six experts in the application of screw theory in robotics and up to 40 participants at the University of Bologna,Bologna,Italy.The school will teach attendees how to apply existing methods and empower them to develop new ones in their own research.The basic theoretical notions will be introduced in a rigorous manner,emphasizing examples,applications,and exercises.Scholarships are available.     

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.