基于多目标遗传算法的水陆两栖可变形机器人结构参数设计方法

水陆两栖可变形机器人是一种兼具变形能力与两栖环境适应能力的新型移动机器人。在其机构设计中,结构参数直接影响该机器人在任务环境中的各项机动性能。针对水陆两栖可变形机器人工作环境复杂性和任务多变性,提出一种基于多目标遗传算法的机器人结构参数设计方法,以得到该型机器人在两栖环境中的最优的综合性能。在水陆两栖可变形机器人陆地环境和水环境中运动学和动力学模型基础上,建立两栖环境中机器人的机动性能指标函数与结构参数的映射关系,并在此基础之上构建面向水陆两栖可变形机器人的结构参数设计的多目标优化问题。利用多目标遗传算法得到该多目标机构参数设计问题的Pareto最优解集,并且通过组合赋权方法确定各目标决策属性的权重,从Pareto最优解集中得到符合设计要求的水陆两栖可变形机器人的各项机构参数最优解,进而指导机器人最终结构参数设计。根据最终得到的结构参数研制出水陆两栖可变形机器人样机Amoeba-II,并在两栖环境下进行样机的各项性能试验,最终验证了基于多目标遗传算法的机器人结构参数设计方法的有效性以及在机器人设计中的适用性。     

基于遗传算法的水空两栖机器人可变形翼剪叉机构优化设计

针对水空两栖机器人可变形翼的剪叉机构拟合问题，根据最优化思想，构建剪叉机构的几何模型，提出了一种优化算法以及优化流程框架。应用遗传算法对剪叉机构几何参数进行优化设计，探究剪叉单元数量与拟合误差值之间的关系，分析了优化结果对变形翼的影响，对水空两栖机器人可变形翼剪叉机构的设计有一定帮助。     

两栖球形机器人的路径规划策略

两栖机器人的水下路径最优规划是目前机器人运动控制研究领域的热点和难点。本文针对两种基于视觉伺服的广义约束优化(GCOP)和序列二次规划(SQP)的机器人运动控制算法进行对比分析,结合视觉伺服传感器,实现了两栖机器人最佳路径的规划、监测动态目标标定、移动目标监测、水下障碍物识别和目标跟踪。利用球形机器人的结构对称特性及阿基米德浮力原理,并结合模糊控制算法对水舱水位进行实时控制,使球形两栖机器人在水下能实现水下多自由度运动。最后,进行了算法的仿真和水下运动实验。实验结果表明,GCOP算法和SQP算法在相对障碍物的有限距离内,SQP算法规划的路径更加合理;而在达到目标坐标位置上,两种算法的误差为167.5 mm,SQP算法在水下路径规划上更加有效。     

DEPSO算法在永磁直线电机结构优化设计中的应用

将传统优化算法应用于直线电机结构优化设计时,传统算法的易早熟与收敛速度慢的缺陷降低了优化效率,并且由于直线电机特有的磁场效应,无法用解析方法准确计算推力波动。为此,提出一种粒子群和差分进化的混合优化算法(DEPSO算法)。该算法在粒子进化过程中,利用差分进化的变异、交叉和选择操作产生新的个体最优位置,优化粒子进化方向。将该算法与有限元数值分析相结合,对直线电机结构参数进行了优化。具体实例的试验结果表明,优化后磁阻力峰值显著下降,证明了DEPSO算法对解决此类问题的有效性。     

改进DE算法求解混合流水车间负荷平衡问题

为解决混合流水车间不相关并行机负荷平衡排产优化问题,建立了混合流水车间负荷平衡优化问题数学模型,以并行工位加工时间负荷平衡代价与总工位等待时间加权求和之值作为负荷平衡评价指标。全局优化算法采用双种群自适应差分进化算法,该算法设计了新的双种群结构和协同进化方式,并引入随停止代数自适应调整进化参数的策略,以增强跃出局部极值、保持进化活力的能力。为进一步提高算法搜索最优解效率,设计了一种基于负荷平衡选择概率的初始种群建立方法,以提高初始种群中初始解的质量、缩小有效解空间。基于汽车生产中的实例数据,将双种群自适应差分进化算法与遗传算法、差分进化算法、自适应差分进化算法进行仿真比较,结果表明,双种群自适应差分进化算法的负荷平衡评价指标有显著的降低。     

基于双种群混沌搜索粒子群算法的机器人喷涂轨迹协同优化

针对笛卡尔空间与关节空间的映射非线性,喷涂轨迹和关节轨迹不满足混合约束的问题,提出基于双种群混沌搜索粒子群优化(DCSPSO)算法的机器人喷涂轨迹协同优化.根据预选取的轨迹特征点构建关节角度序列,以机器人的喷涂效率和运动稳定性为目标建立关节轨迹多目标优化模型,利用DCSPSO算法求解优化模型得到Pareto最优解,使关节轨迹满足机器人运动学约束,最后根据理论轨迹与反馈轨迹的弦高误差和漆膜厚度误差建立喷涂轨迹误差模型,并验证最优解的质量,使喷涂轨迹满足加工精度约束.通过实例表明,DCSPSO算法较多目标遗传算法等经典多目标优化算法具有更强的全局和局部搜索能力,利用轨迹误差模型可合理增加特征点,使理论轨迹与反馈轨迹的最大弦高误差从12.619 mm降至1.587 mm,最大漆膜厚度误差从11.47 μm降至1.18 μm.     

进化蒙特卡洛优化的SVM在故障诊断中的应用

针对支持向量机超参数选择问题,将进化蒙特卡洛算法引入支持向量机的参数优化.以交叉验证误差作为目标函数,并行运行多条马尔可夫链,设计了一种改进的变异操作.使得算法在进化的初期具有较强的全局搜索能力,在进化的后期具有精细的局部搜索能力,从而加速马尔可夫链的混合,提高算法的寻优效率,最后将优化的支持向量机应用于滚动轴承故障诊断.试验结果表明,该方法具有较高的寻优效率和参数优化能力,可提高故障识别的精度.     

带缓冲流水车间成组调度问题的混合微分算法

针对流水车间成组调度问题,加入序列相关的准备时间和有限缓冲的约束,以最小化总流程时间为目标建立数学模型,提出一种混合微分进化算法。该算法将微分进化算法和禁忌搜索算法相结合,利用微分进化的并行性搜索确定各组内的零件顺序,应用禁忌搜索寻找最优的零件组顺序。为提高求解速度和精度,利用构造算法产生问题的初始优化解,并通过数值实验确定算法的最优参数。通过算例实验以及与其他算法的比较,验证了所提算法的有效性。     

考虑交货期配置的预制构件订单接受与调度

针对预制构件交货期配置、订单选择与生产调度需要同时决策的问题,在充分考虑中断和不可中断工序、串行和并行工序等复杂工况特点的基础上,以最大化总净利润为目标,建立了混合整数规划集成调度优化模型。分析了固定调度下的交货期配置性质并给出最优交货期配置策略,在此基础上提出一种基于问题知识导向的混合迭代贪婪算法求解该问题。为提高算法效率,在该算法的目标评价阶段通过集成最优交货期配置策略快速计算给定调度对应的最优目标值,克服了枚举交货期方法中目标函数评价困难的问题;同时为提高搜索精度,在局部搜索阶段设计了一种基于插入和交换结构的快速变邻域上升(VNA)搜索策略。通过实验验证了所提算法的优越性以及最优配置策略和VNA搜索策略的有效性。     

基于双种群遗传混沌优化算法的最优时间轨迹规划

针对以最短运行时间为目标的工业机器人轨迹规划问题,提出一种基于混沌局部搜索的双种群遗传最优时间轨迹规划算法。首先以各个节点之间的时间间隔之和为优化目标,以各关节的角速度、角加速度和角加加速度为约束条件,利用五次多项式拟合规划的关节空间位置节点模拟机器人的运行轨迹;然后,利用双种群遗传算法全局搜索能力强、进化速度快和混沌算法局部搜索能力强的优点,提出一种基于双种群遗传混沌优化算法的机器人轨迹规划方法,规划最优时间轨迹;最后,以3自由度空间机械臂为例,验证了所提算法能够使机器人末端执行器的运行轨迹平滑且时间最优。该算法应用于机器人轨迹规划可以延长机器人使用寿命,提高生产效率。     

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。     

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....     

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.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.