基于二次规划的速度平滑实现方法

本文基于凸优化理论,设计了一种基于二次型的智能驾驶车辆速度平滑的方法,目的是满足给定约束下,如速度、加速度、加加速度、运动学方程等,获取全局最优解,以满足纵向速度规划的安全性与舒适性。首先,创建状态向量,状态向量包含速度、加速度及速度、加速度、加加速度的松弛因子,其中松弛因子用于速度、加速、加加速度的软约束。然后,建立目标函数,并化为二次型的形式。最后,设计状态量的约束,并将矩阵及约束输入osqp求解器,用于求解全局最优解。为了验证算法效果,本文设计了仿真实验及卡车高速的道路试验。结果表明,所提出的方法能够显著提高纵向控制的舒适性与安全性,并且具有很好的适应性和鲁棒性。     

基于遗传模拟退火融合算法的船舶分段装配序列优化

针对复杂船舶分段装配序列规划问题,提出基于遗传模拟退火算法的分段装配序列规划求解方法,综合考虑分段装配中的工艺约束和几何约束,建立以分段装配所需时间和消耗成本为优化目标的问题模型,并为模型求解设计了遗传模拟退火融合算法,将模拟退火算法的局部搜索能力与遗传算法的快速全局搜索能力相结合,达到快速收敛到全局最优解的目的.通过实例验证了该算法的有效性.     

风洞上攻角机器人轨迹规划算法研究与实现

为了提高机械臂跟踪目标轨迹的运动速度,对其目标轨迹进行二次规划。该轨迹规划算法通过引入路径参数s,将关节速度、力/力矩等约束转化为关于路径参数的约束,分别求取关节速度与力/力矩约束限制下路径参数s的最大速度曲线,对最大速度曲线求交集,获得多重约束最大速度曲线。采用模糊推理方法对目标轨迹进行离散化处理,减小优化规模;以0值加速度曲线乘以比例系数Kv替代关节力/力矩约束的最大速度曲线,提高算法的计算效率;通过速度特征点算法与修型射靶算法对规划得到的轨迹进行修形,确保修形后的目标轨迹满足关节速度、力/力矩的约束,并且速度曲线光滑。实验表明,该轨迹规划算法对不同复杂程度的目标轨迹都有着较好的规划性能,能够得到连续平滑的时间近似最优轨迹。     

基于凸优化的举高消防车时间最优轨迹规划

为提高举高消防车作业的及时性、可靠性与安全性,提出一种考虑动作平稳、无冲击的时间最优轨迹规划算法。引入伪位移参量s表示路径,利用B样条曲线对举高消防车臂架系统各个关节运动离散点进行拟合,构造连续运动几何路径。结合连续路径,以s及其对于时间的各阶导数表示时间最优目标函数与各个关节速度、加速度约束,建立时间最优轨迹规划的凸优化模型。利用B样条曲线以有限维矢量x表示轨迹,采用内点法对凸优化模型进行求解,在保证速度、加速度、加加速度连续的条件下求得最优解,进而得到各个关节的运动轨迹。利用提出的方法对大高度举高消防车进行轨迹规划,经仿真表明,在满足动作平稳性的同时得到时间最优运动轨迹。     

基于凸优化的车载复合电源参数匹配

提出一种电动汽车复合电源参数快速匹配方法,对复合电源参数和能量管理策略同时进行优化。为避免动态规划或者进化算法在求解此类优化问题时出现的计算负担大或结果次优的问题,应用凸优化原理对优化问题进行求解。对复合电源模型进行线性近似,并引入新变量对优化问题中的目标函数和约束进行转换,将优化问题转化为凸优化问题,最后应用Matlab/cvx工具箱进行求解。应用动态规划求解此优化问题并对比优化结果:凸优化和动态规划结果相差在4%以内,凸优化保证了全局最优;凸优化耗时不超过100 s,明显优于动态规划,有良好的工程应用潜力。凸优化结果表明:通过增加最大不超过60 W·h的超级电容组能够延长电池组一倍的寿命里程,改变凸优化问题的权重可以快速获取所需参数。     

基于动态轮廓误差的微段速度规划并行算法

为提高数控高速加工精度,使算法更加高效,提出了微段速度规划动态轮廓误差约束模型,该模型针对微段轨迹建立了轮廓误差对拐点速度的约束条件,并给出了一种基于图形处理器的并行规划算法,引入速度规划单元概念将轨迹均匀划分,在提高并行计算负载平衡的同时,使各并行线程可以进行相对独立的计算。实验表明,该算法加工速度连续平滑,能有效保证轮廓精度要求,并行算法比串行算法计算效率成倍提高。     

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.     

用于供水系统直接优化调度的蚁群改进算法

在城市供水系统中建立了多目标在线直接优化调度模型,并对影响优化调度的各方面因素进行了系统的分析和挑选。使用化多为一的乘除法,将该多目标决策问题转化为单目标问题求解,提出了使用乘法形式的罚函数将模型中的约束函数转化为目标函数。采用蚁群算法求解调度模型。为了更好地得到全局最优解,对算法进行了改进,加入了更多的决策点,实现蚁群算法的二进制编码方法,并采用单只最优蚂蚁更新路径上的外激素值、外激素值限定在一定范围内等改进方法。使用改进算法实现了某小区供水系统的直接优化调度,并与遗传算法优化调度的过程进行了对比,新算法在优化时间及得到最优解的次数上都优于遗传算法。     

行星变速器的模糊可靠性多目标优化设计

以提高行星传动系统效率和增大系统可靠性并尽量减轻整机的重量为目标函数,通过线性加权函数法确定目标函数的数学模型,采用设计变量规格化的方法确定加权因子,基于模糊数学理论的可靠性约束条件以及功能进行几何约束,运用Matlab优化工具箱进行优化,对三个局部最优解叠加计算,保证了优化参数是满足目标函数的全局最优解.通过实例表明...     

基于NSGA-Ⅱ的智能化电铲多目标最优挖掘轨迹规划

为实现智能化电铲实时节能的挖掘,提出了一种基于非支配排序遗传算法(Non-dominated Sorting Genetic Algorithm-II,NSGA-Ⅱ)的智能化电铲多目标最优挖掘轨迹规划方法。首先,通过拉格朗日方程建立智能化电铲工作装置动力学模型;然后,使用高次多项式对挖掘轨迹进行插值,将挖掘轨迹寻优问题转化为多项式系数寻优问题,最后,以挖掘时间最短及单位体积物料的挖掘能耗最小作为优化目标,以电机性能与挖掘过程中几何条件等作为约束,利用多目标优化平台PlatEMO,将NSGA-Ⅱ作为多目标优化算法,指定待优化问题的目标函数及约束函数,获取到多目标优化Pareto最优解集,基于决策偏好设置权重并根据TOPSIS法获取最优解,得到多目标最优挖掘轨迹规划结果。结果表明,优化后挖掘轨迹满足实时节能的挖掘要求。     

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.