ABC算法在非线性系统辨识与控制中的应用

针对非线性系统辨识和控制器的设计,提出一种混沌映射产生初值的人工蜂群优化算法,并将该算法应用于非线性系统中的参数辨识和PID控制器的设计。参数辨识的仿真结果表明,基于混沌映射理论的人工蜂群优化算法比其他传统的算法具有更好的收敛特性和辨识性能;自动电压调节系统的仿真结果表明,基于混沌人工蜂群优化的PID控制自动电压调节系统是可行性的,且具有良好的动态调节性能。     

基于混沌蜂群算法的农用无人直升机路径规划

针对农用无人直升机从地面站飞到目标农田的路径规划问题,提出了一种改进的人工蜂群算法。在该算法中利用混沌局部搜索算子的遍历性和随机性的特点重新初始化陷入局部最优解的雇佣蜂,在迭代中产生局部最优解的邻域点,帮助其脱离束缚并快速找到全局最优解。采用改进算法来处理无人直升机的路径规划任务,首先将路径规划任务通过数学建模转换成一个多维函数优化问题,然后结合人工蜂群算法的全局寻优能力和混沌算子的局部搜索能力得到改进算法,最后分别用仿真实验验证了改进算法在函数优化上的优越性和在解决农用无人直升机路径规划上的可行性。     

搜索空间自适应调整蜂群算法的起重机主梁优化

为了减轻起重机主梁自身重量、实现主梁轻量化,提出了搜索空间自适应调整蜂群算法的主梁优化设计方法.建立了起重机主梁轻量化设计数学模型;以传统人工蜂群算法为基础,提出了蜂群搜索空间随迭代次数自适应缩减方法,直至最终锁定最优值区域;充分利用混沌系统的遍历性和随机性,使用混沌搜索蜜源代替停滞蜜源,不仅跳出了局部极值,而且实现了蜜源进化,有效提高了算法收敛速度和寻优精度.使用搜索空间自适应调整的混沌蜂群算法和传统算法求解主梁优化数学模型,改进算法优化的主梁面积比企业主梁截面积减少了2.77％,而传统算法只减少了2.42％;对优化后主梁进行有限元分析可知,主梁优化后依然满足约束条件,符合设计使用要求.     

基于人工蜂群算法的线性系统辨识

针对以传递函数描述的线性系统,提出一种基于人工蜂群算法的辨识算法。首先,基于系统的阶跃响应得到系统的输出;其次,确定线性系统的辨识模型形式,确定需要辨识的参数区间;最后,确定目标寻优函数,利用人工蜂群算法的全局寻优能力,得到系统辨识模型。仿真实验表明,本文提出的辨识算法具有较高的辨识精度。     

基于蜂群算法的汽车悬架参数优化设计

针对汽车悬架系统参数选取的不足,综合局部精英策略局部搜索能力强和人工蜂群算法全局搜索效率高的优点,提出基于局部精英策略人工蜂群算法确定其参数的优化方法。利用Matlab/Simulink仿真软件,以积分白噪声模型作为路面输入模型,对悬架系统进行仿真研究。仿真结果表明,局部精英策略人工蜂群算法相对传统算法和人工蜂群算法具有一定的优越性,通过对汽车悬架系统参数的优化可改善汽车的行驶平顺性和操纵稳定性。     

应用混沌萤火虫算法的无人机航迹规划

针对无人机在复杂多变环境下的飞行问题,提出了一种应用混沌萤火虫算法的航迹规划方法。在飞行区域已知的情况下,建立规划空间的二维模型与航迹代价模型,并将航迹规划问题转换成多维函数优化问题;利用萤火虫算法优越的寻优能力来搜索无人机的最优航线;引入立方映射混沌算子来提高算法的局部搜索能力和鲁棒性。通过标准函数测试与航迹规划仿真对提出的算法进行了验证,结果表明:相比其他算法,本算法能够较好地跳出局部最优的束缚,并快速、准确地获得全局最优解,可以满足无人机航迹规划的要求。     

改进ABC算法求解认知无线网络频谱分配问题

针对认知无线网络中频谱分配问题,提出了一种基于改进人工蜂群算法的多目标组合优化算法。首先将频谱分配问题转换成多目标优化问题,然后利用人工蜂群算法的寻优能力来实现频谱最优的分配方案。其中,在雇佣蜂搜索阶段采用新型杂交算子加快收敛速度;跟随蜂搜索阶段引入一种新的概率选择方式保证种群多样性;侦察蜂搜索阶段利用混沌算子来提高全局搜索能力。最后,通过频谱分配仿真对这里提出的算法进行了验证,结果表明:与其他算法相比,这里算法能够较好地跳出局部最优的束缚,具有优化效果佳、稳定性好、鲁棒性强的优点,可以在满足多个优化目标的前提下获得更合理的频谱分配方案。     

两级定位—路径问题的路径重连变邻域搜索人工蜂群算法

为适应物流需求从少品种大批量到多品种少批量的转变,建立了两级定位—路径问题的数学模型,提出求解该问题的路径重连变邻域搜索人工蜂群算法,即在基本人工蜂群算法中嵌入近年来广泛应用于组合优化问题求解的两种启发式搜索策略——变邻域搜索和路径重连。采用Lingo求解小规模两级定位—路径问题;选取三组较大规模的两级定位—路径问题,分别采用基本人工蜂群算法、路径重连人工蜂群算法、变邻域搜索人工蜂群算法和路径重连变邻域搜索人工蜂群算法进行求解。结果表明,所建数学模型是正确的,所提算法不但能够取得更好的优化结果,而且具有更好的收敛性。     

混合人工蜂群算法在混流装配线排序中的应用

为更好地解决混流汽车装配线排序问题,建立了以最小化总调整时间和最小化超载时间与空闲时间为优化目标的典型混流装配线排序数学模型,提出一种求解该模型的混合人工蜂群算法。针对标准人工蜂群算法不能解决离散问题的缺陷,引入禁忌搜索算法重新设计了蜂群的邻域搜索算法,设置了算法邻域搜索的动态参数,设计了禁忌搜索算法在人工蜂群算法中的嵌入策略;为保证算法的全局收敛性,采用基于跟随蜂的精英保留策略,给出了侦查蜂和跟随蜂的食物源更新方法。通过比较混合人工蜂群算法与遗传算法和标准人工蜂群算法对不同规模算例的计算结果,验证了所提算法在求解混流装配线排序问题中的优越性。     

混流装配排序问题的改进人工蜂群优化

为解决离散的混流装配线作业排序问题,提出一种基于人工蜂群优化算法的改进算法。采用NEH启发式方法优化初始种群质量;在雇佣蜂算法中建立了变邻域区域搜索机制并嵌入模拟退火算法,提高了算法的搜索精度与广度;提出一种最优控制策略,通过限制最优解群体的成长速度,有效降低了种群相似度,提高了算法的全局搜索性能。实验方面,算法参数通过标准算例仿真对比设定,并采用Benchmark标准算例对所提算法与标准人工蜂群优化算法、遗传算法、混合遗传算法、改进粒子群优化等算法进行了对比。通过一个混流排序实例的仿真,对比证明了算法在求解混流装配线排序问题上的有效性。     

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...     

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.     

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.     

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....     

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.