自适应退火遗传算法的起重机箱形梁优化

为克服标准遗传算法的固有缺陷——停滞和早熟现象,将具有较强局部收索能力的模拟退火算法融入其中,对适应函数进行退火拉伸,对接受算子进行退火处理,同时加入自适应机制来改进标准遗传算法的杂交率和变异率,尤其对变异率的调整,使其既能根据个体适应值的大小进行自适应修正,也能随进化状态的改变而改变,从而增强了算法摆脱局部最优解的能力.以最终形成了自适应退火遗传算法进行起重机主梁优化.经实例验证:与原标准遗传算法相比,在保证收敛结果不变的情况下,收敛速度和全局收敛性都得到了较大提高.     

一种求解车间调度的混合免疫遗传算法

为了克服传统免疫遗传算法(IGA)在车间调度问题上易陷入局部最优的缺点,将免疫遗传算法(IGA)与模拟退火算法(SA)进行了结合,提出一种应用于车间作业调度的混合免疫遗传算法。为了有效的提高免疫遗传算法收敛速度和避免算法陷入局部最优解,此算法设计了一种基于适应度和浓度的自适应精英保留策略且重新设置了变异算子,即将变尺度变异和自适应变异算子进行了融合。最后利用"Muth and Thompson"基准问题进行仿真实验,验证了该算法在JSP问题中的高效性和可行性。     

混合遗传算法在桥式起重机结构优化中的应用

针对工程中的变量离散化问题，提出了一种将遗传算法和模拟退火算法相结合的混合算法。该算法发挥了遗传算法和模拟退火算法的优越性，避免了遗传算法的早熟收敛问题，增强了算法的全局收敛性，并提高了算法的收敛速度。通过对桥式起重机金属结构进行优化，其结果与MDOD和改进遗传算法2种的结果进行比较，表明此算法能够很好处理工程离散化问题。     

基于改进遗传算法的RV减速器选配方案研究

为了解决传统的人工选配方法在生产高精度RV减速器时面临的问题，提出了一种基于改进遗传算法的选配方案。该方案旨在实现批量生产装配数量最多且传动精度最优的一批RV减速器，并以最高匹配成功率为目标。该算法结合了RV减速器的结构特征，采用整数编码的方式对染色体进行编码，对交叉和变异操作进行改进，同时，引入了模拟退火算法和自适应调整策略，以提高算法的全局搜索能力和收敛速度。试验结果表明：基于改进遗传算法的选配方案具有更快的收敛速度和更强的全局搜索能力，可有效避免传统遗传算法出现的局部最优解问题，从而实现了较高的匹配成功率。该算法不仅能够为生产高精度RV减速器提供有效的解决方案，还有广泛的实际应用前景。     

机器人逆运动学的模拟退火自适应遗传算法

对5自由度关节型机器人的运动特点进行分析,并建立该机构的运动模型.在基本遗传算法的基础上,针对求解串联机器人运动学逆解的特殊性,为了消除遗传算法易陷入局部最优或早熟问题,提出一种新颖的改进遗传算法,采用模拟退火和自适应策略,保证其收敛性并加快收敛速度.仿真结果表明,该算法求解精度高,收敛速度快,且稳定性好.     

基于混合遗传算法的Job Shop问题研究与实现

遗传算法具有良好的全局搜索能力,在调度问题中得到了广泛的应用。通过对遗传算法进行改进,可以有效避免在求解过程中容易陷入局部最优域的问题。通过采用混合遗传算法,即将模拟退火算法与遗传算法结合,在种群更迭过程中引入了模拟退火操作来求解Job Shop问题。通过实验验证了混合遗传算法的特性,最终算法显示出了遗传算法较好的搜索能力和模拟退火避免过收敛的特性,改进了收敛性能。系统的运行结果满足调度要求,实现了良好的有效性和实用性。     

基于混合遗传算法的车间调度研究

针对用遗传算法求解车间调度问题(job shop problem)容易早熟的缺点,对遗传算法的收敛性、搜索效率和最优解等方面进行了研究,改进了遗传算法,引入了模拟退火算法,提出了新的混合遗传算法。重新设计了基于工件编号的交叉算子和变异算子;采用自适应交叉概率和变异概率;在每一代遗传进化中引入了Metropolis接受准则。通过结合遗传算法、自适应概率和模拟退火算法的各自优点,提高了算法搜索能力。用遗传算法、模拟退火算法和混合遗传算法对Job Shop Problem中FT06问题进行了仿真。仿真结果表明,混合遗传算法提高了搜索效率,能够找到最佳的调度方案。     

嵌入筛选操作的遗传算法及其在焊接路径规划中的应用

针对基本遗传算法(GA)中存在的局部搜索能力不足和未成熟收敛的问题,引入一种结合模拟退火算法的筛选操作对算法进行改进.改进遗传算法(IGA)一方面在优化后的解空间进行精细寻解,另一方面依靠基本GA算子开拓全局搜索空间,从而使算法达到全局最优与局部优化的良好平衡.由于改进算法中采用了模拟退火算法的Metropolis准则对染色体进行筛选,强化了算法局部搜索能力,有效加快了算法收敛速度.并以汽车车身机器人焊接路径规划为应用背景,对改进遗传算法进行了仿真验证,仿真结果验证了所提算法的有效性,并且验证了其在汽车车身焊接路径规划中应用的可行性.     

基于符号函数的自适应遗传算法的研究与应用

交叉概率和变异概率的选择是决定遗传算法行为和性能的关键,直接影响算法的收敛性.自适应遗传算法在前期收敛速度缓慢,而且容易陷入局部最优.针对此局限,本文提出了基于符号函数的自适应遗传算法,将交叉算子与变异算子控制在期望区间内变化,增强了全局搜索能力,提高了收敛速度.最后进行了仿真实验,通过比较两个优化实例,验证了本文所提出算法的有效性,且符合工程实际需要.     

基于GASA优化算法的自适应协同优化方法

针对协同优化方法收敛困难、优化效率低的问题,采用自适应概念与混合优化算法对其进行改进.采用基于学科优化解的差异信息构造自适应惩罚函数,将系统级约束条件进行转化,重新构建系统级的优化模型,克服了协同优化内部定义缺陷所造成的收敛困难.结合协同优化的优化特征,采用兼备遗传算法与模拟退火算法两者优点的混合算法作为协同优化系统级优化算法,提高了协同优化寻优效率.以飞机起落架缓冲器优化问题为例验证了该方法,结果表明该方法提高了协同优化的搜索效率与收敛速度,优化性能良好.     

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...     

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.     

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.     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.     

Fractional order nonsingular terminal sliding mode control for flexible spacecraft attitude tracking

This paper investigates a fractional terminal sliding mode control for flexible spacecraft attitude tracking in the presence of inertia uncertainties and extern...     

奥氏体不锈钢表面双辉等离子渗锆的动力学

利用双辉等离子渗金属技术在0Cr18Ni9Ti奥氏体不锈钢表面制备了一层均匀、致密、呈良好冶金结合的渗锆合金层,并对1 060℃下的渗锆动力学进行了研究。结果表明:随着距锆合金层表面距离的增加,锆元素的含量呈梯度递减,扩散系数逐渐减小,而扩散激活能逐步增大;在1 060℃采用双辉等离子技术渗锆时,渗锆合金层表层的空位密度为2.945×(1012~1013)cm-2,与相同温度下采用常规渗金属工艺相比,提高了1~2个数量级。     

气化炉三维扫描测量与数据处理

以德士古气化炉耐火砖的内壁蚀损检测设备为基础,对采集到的点云数据做了进一步处理.通过对数据的筛选和剔除,实现了数据点的平滑降噪细化和精简.然后利用点云对整、网格划分和分色显示等方法,最终完成了内壁腐蚀情况的三维建模.重点讨论了点云数据的预处理及后处理的方法,并根据内壁耐火砖的腐蚀阈值,提出了一种气化炉内壁腐蚀区域的识别与分割方法.对耐火砖的腐蚀分析、气化炉的生产与维修提供了可靠依据,并在工程应用中获得了一致认可.