Integrated Optimization of Structure and Control Parameters for the Height Control System of a Vertical Spindle Cotton Picker

Vertical picking method is a predominate method used to harvest cotton crop.However,a vertical picking method may cause spindle bending of the cotton picker if spindles collide with stones on the cotton field.Thus,how to realize a precise height control of the cotton picker is a crucial issue to be solved.The objective of this study is to design a height control system to avoid the collision.To design it,the mathematical models are established first.Then a multi-objective optimization model represented by structure parameters and control parameters is proposed to take the pressure of chamber without piston,response time and displacement error of the height control system as the opti-mization objectives.An integrated optimization approach that combines optimization via simulation,particle swarm optimization and simulated annealing is proposed to solve the model.Simulation and experimental test results show that the proposed integrated optimization approach can not only reduce the pressure of chamber without piston,but also decrease the response time and displacement error of the height control system.

Identification of time-varying system and energy-based optimization of adaptive control in seismically excited structure

The combination of structural health monitoring and vibration control is of great importance to provide components of smart structures.While synthetic algorithms have been proposed,adaptive control that is compatible with changing conditions still needs to be used,and time-varying systems are required to be simultaneously estimated with the application of adaptive control.In this research,the identification of structural time-varying dynamic characteristics and optimized simple adaptive control are integrated.First,reduced variations of physical parameters are estimated online using the multiple forgetting factor recursive least squares(MFRLS)method.Then,the energy from the structural vibration is simultaneously specified to optimize the control force with the identified parameters to be operational.Optimization is also performed based on the probability density function of the energy under the seismic excitation at any time.Finally,the optimal control force is obtained by the simple adaptive control(SAC)algorithm and energy coefficient.A numerical example and benchmark structure are employed to investigate the efficiency of the proposed approach.The simulation results revealed the effectiveness of the integrated online identification and optimal adaptive control in systems.

Integrated design optimization of composite frames and materials for maximum fundamental frequency with continuous fiber winding angles

Fiber reinforced composite frame structure is an ideal lightweight and large-span structure in the fields of aerospace,satellite and wind turbine.Natural fundamental frequency is one of key indicators in the design requirement of the composite frame since structural resonance can be effectively avoided with the increase of the fundamental frequency.Inspired by the concept of integrated design optmization of composite frame structures and materials,the design optimization for the maximum structural fundamental frequency of fiber reinforced frame structures is proposed.An optimization model oriented at the maximum structural fundamental frequency under a composite material volume constraint is established.Two kinds of independent design variables are optimized,in which one is variables represented structural topology,the other is variables of continuous fiber winding angles.Sensitivity analysis of the frequency with respect to the two kinds of independent design variables is implemented with the semi-analytical sensitivity method.Some representative examples in the manuscript demonstrate that the integrated design optimization of composite structures can effectively explore coupled effects between structural configurations and material properties to increase the structural fundamental frequency.The proposed integrated optimization model has great potential to improve composite frames structural dynamic performance in aerospace industries.

Structure Analysis and Control Optimization on High Speed Lift Platform

Dynamic analysis of scissor hydraulic lift platform has been performed to invest/gate the key factors which determine size and shape of the platfolan. By using MATLAB, the position of hydraulic cylinder has been optimized to reduce jacking force of piston and the whole system. Thus structure deformation decreases which is beneficial to control accuracy. Additionally, a new proportion integration differentiation （PID） control mode based on BP neural network has been developed to improve the stability and accuracy for the pasitio^L control in this system. Compared with existing PID tuning meth~~ls and fuzzy self-adjusted PID controllers, the proposed back propagation （BP） based PID controller can achieve better performance for a wide range of complex processes and realize self-tuning of parameters. It was confirmed that the performance of the lift platform regarding the force variation and position accuracy was greatly enhanced by optimizing of the system both in structure and control. Considerable economic benefit can also be achieved thrangh the application of this intelligent PID system.

Integrated batteries layout and structural topology optimization for a solar-powered drone

The purpose of this paper is to demonstrate an integrated optimization scheme for a solar-powered drone structure.Consider a primary beam in the wing of large aspect ratio,where 100 lithium batteries are assembled.In the proposed integrated optimization,the batteries are considered here as parts of the load-carrying structure.The corresponding mechanical behaviors are simulated in the structural design and described with super-elements.The batteries layout and the structural topology are then introduced as mixed design variables and optimized simultaneously to achieve an accordant load-carrying path.Geometrical nonlinearity is considered due to the large deformation.Different periodic structural configurations are tested in the optimization in order to meet the structural manufacturing and assembly convenience.The optimized designs are rebuilt and tested in different load cases.Maintaining the same structural weight,the global mechanical performances are improved greatly compared with the initial design.

Ultrahigh-power electrochemical double-layer capacitors based on structurally integrated 3D carbon tube arrays

The rational design of electrodes is the key to achieving ultrahigh-power performance in electrochemical energy storage devices.Recently,we have constructed well-organized and integrated three-dimensional(3D)carbon tube(CT)grids(3D-CTGs)using a 3D porous anodic aluminum oxide template-assisted method as electrodes of electrical double-layer capacitors(EDLCs),showing excellent frequency response performance.The unique design warrants fast ion migration channels,excellent electronic conductivity,and good structural stability.This study achieved one of the highest carbon-based ultrahigh-power EDLCs with the 3D-CTG electrodes,resulting in ultrahigh power of 437 and 1708 W·cm−3 with aqueous and organic electrolytes,respectively.Capacitors constructed with these electrodes would have important application prospects in the ultrahigh-power output.The rational design and fabrication of the 3D-CTGs electrodes have demonstrated their capability to build capacitors with ultrahighpower performance and open up new possibilities for applications requiring high-power output.

Static and dynamic design based on hierarchical optimization for materials and structure of porous metals

A static and dynamic collaborative optimization method for materials and structure with uniform periodic microstructure is presented.The sensitivity formulae of hierarchical optimization,i.e.,material design,structure design and integrated design for porous metals,are given.On the base of the hierarchical optimization model,numerical experiments of an MBB beam and a cantilever one were carried out.Based on porous metals bearing multi-functionality,the differences and applicability of hierarchical optimization are discussed in the structure loading field.It is concluded that structure design is mainly oriented to structure efficiency,material design is mainly oriented to multi-functionality,and integrated design is oriented to structure efficiency and multi-functionality.This work provides some useful ideas for the selection of porous metals design method.

基于STM32的智能航行系统设计

为解决航行器智能确定航向并航行的问题,本文采取模块化的思想设计了一款基于STM32的红外导引的智能航行控制系统。该智能航行系统利用红外接收模块进行红外导引信号的接收,采取线性加权法进行航向与导引信号之间的偏离角确定,利用比例-积分-微分(proportion-integration-differentiation,PID)控制算法对控制舵机转角的脉冲宽度调制(pulse width modulation,PWM)信号的占空比进行确定,从而对螺旋桨的转速与舵桨的转角进行可靠控制。根据水池测试结果,该智能航行控制系统能够对红外接收信号进行快速处理,在保持较高航速的条件下进行可靠的航行控制。

气流分选技术研究进展

双碳背景下,气流分选技术因污染低、成本低、不用水、投资省、工艺简单等优势备受关注。为提升气流分选技术在多领域、多地区、多工况的适应性,解决气流分选物料适用范围窄、细粒分选效率低、设备大型化难等问题迫在眉睫。围绕气流分选理论、技术应用和技术改进3方面系统评述气流分选技术研究进展。首先,介绍了气流分选技术原理,分析气流分选过程颗粒受力及分选理论进展;其次,综述了气流分选在固废、矿业、农业等领域的应用进展,并评析了技术优势和技术短板;再次,系统分析了气流分选供风方式优化和设备结构优化等技术改进进展;最后,给出了通过单体并联和相似放大准则提高设备处理量,通过预干燥、分选干燥一体化、改进入料方式提高潮湿物料适应性与分散性,通过窄粒级分选和保持物料形状一致性的预处理过程提高细粒和薄片物料分选效率等路径。展望了未来气流分选技术在线检测与控制智能化、分选装备大型化、分选效率精细化、分选工艺联合化等方面的发展方向,为气流分选技术进一步研究和推广应用提供重要依据。

高速铁路列车运行图一体化自动编制方法研究

高速铁路列车运行图编制不仅要在图面上生成列车运行线,还要考虑客运需求、车底交路运用、车站股道运用等问题,影响因素众多,且各影响因素相关性较强,因而我国高速铁路列车运行图一直以来都采用人工铺画方式,缺少计算机一体化自动编制方法。为进一步提高高速铁路运行图编制效率,在借鉴人工编图经验的基础上,提出基于车底交路方案、列车结构方案及调整策略的高速铁路列车运行图一体化自动编制流程,同时生成列车时刻表、车底交路方案、车站股道运用方案。针对不易处理的列车运行图结构优化问题,设计微观站场进路占用策略与运行图优化编制模型,并以京沪高速铁路为例进行验证,用时48 h重新铺画运行图,各项指标与真实运行图相近,大幅减少了现有运行图编制模式对人力物力的消耗,为高速铁路列车运行图编制提供一种自动化的理论与技术支撑。

无人艇载多波束测深系统一体化结构优化设计

为了提升无人艇载多波束测深系统(以下简称多波束系统)在复杂环境下的作业安全和精度,通过对多波束系统与无人艇艇型一体化安装结构的分析,采用基于有限元协同仿真技术开展动力及平台结构性能优化设计研究,设计出了在一定航行速度下能保证较优效率和航行安全的无人艇载多波束系统安装结构,并在珠江口海域进行了试验。结果表明:与传统的无人艇平台与多波束系统分离式设计的方法相比,设计的无人艇载多波束系统横摇角度小,抖动现象减弱,作业性能得到提升。运用该系统不仅可以获取水下高精度的三维地形数据,也可以为水下障碍物排查、目标物搜寻和水下构筑物巡检巡查等提供技术支撑。

基于改进自适应多种群遗传算法的结构-控制系统一体化优化

提出一种改进的自适应多种群遗传算法,以更好地解决建筑结构-主动控制系统一体化优化问题,即同时对被控结构参数、控制算法参数、主动作动器布置位置进行优化。该遗传算法对编码方法、初始种群生成、选择策略、交叉概率和变异概率的自适应调整、多种群协同进化中移民策略等进行改进。研究结果表明:改进的自适应多种群遗传算法和改进的基本遗传算法优化结果总体一致,表明前者分析结果是正确的,并且具有较高的精度;改进的自适应多种群遗传算法和改进的基本遗传算法首次得到优化分析最优解的平均进化代数分别为320与730,表明前者比后者收敛速度更快;改进的自适应多种群遗传算法每次能达到或接近最优解,可有效克服基本遗传算法优化结果随机性较强的缺点;经改进的自适应多种群遗传算法优化的主动控制系统取得明显减振效果,E1 Centro波输入时,主动控制结构层间位移角峰值和绝对加速度峰值较无控时分别平均减小54.5%与46.7%。算例结果表明了改进的自适应多种群遗传算法的有效性,实现了对建筑结构-主动控制系统的一体化优化。

星载临边光谱仪反射镜组件优化设计分析

针对星载临边光谱仪离轴凹面反射镜组件高性能要求,对反射镜及其支撑结构进行了详细的光机优化设计。选用微晶玻璃作为载荷材料,通过施加最小尺寸约束的变密度拓扑优化方法确定镜体背部加强筋的分布,将背部筋厚尺寸变量灵敏度分析与局部筋厚多尺寸优化相结合,得到轻量化率为60%的反射镜结构;通过引入综合评价因子Q定量评价优化方案,对支撑结构中主要结构参数进行了多目标优化,获得了性能良好的柔性支撑结构。对优化处理前后反射镜组件进行光机集成分析,结果显示组件重力载荷工况与热力耦合工况下,优化处理后组件静力学性能更优。有限元分析得到组件1阶固有频率为942.2 Hz,正弦扫频试验结果表明组件1阶固有频率为956.5 Hz,分析误差为1.5%,结构动态性能较优;未优化处理组件在重力载荷及热力耦合工况下面型精度较差,而优化处理后组件在重力载荷工况下面型精度均方根值和峰谷值分别为9.5 nm、46.7 nm,在热力耦合工况下面型精度均方根值和峰谷值最大分别为8.25 nm、40.6 nm,对两种工况下反射镜进行面型检测,均方根值误差分别仅为6.1%和6.9%,在误差允许范围内;弥散斑均布于艾里斑内部,表明该凹面反射镜组件结构优化设计符合指标要求。

车架与电池舱一体化结构轻量化与疲劳寿命集成优化设计

为提高电动载货汽车轻量化水平,本文提出了一种车架与电池舱一体化(cell to frame-简称“CTF”)结构。首先建立对标车型车架有限元模型,计算了其静力学性能与自由模态,并通过自由模态试验验证有限元模型的准确性。然后采用道路实采的多工况组合疲劳载荷谱在时域内运用名义应力法进行车架疲劳寿命分析。接着对经有限元分析验证合理的CTF结构初始设计进行试验设计并建立代理模型。最后采用全局响应面法进行优化设计,获得最佳轻量化方案。结果表明,优化设计后,CTF结构质量相较于传统的车架与电池舱分离设计结构轻量139.95 kg,轻量化率达14.09%,同时CTF结构力学性能与疲劳寿命均满足设计要求。

数字新质生产力对城乡高质量融合的影响与机制

数字新质生产力能够深刻改变城市与农村生产及生活方式,对城乡高质量融合具有重要意义。基于2009—2022年我国30个省份(未含香港地区、澳门地区、台湾地区及西藏地区)面板数据,利用固定效应模型、中介效应模型及门限效应模型,实证检验数字新质生产力对城乡高质量融合的影响和作用机制。研究发现,数字新质生产力能够显著促进城乡高质量融合、产业结构升级、公共服务均等化,特别是资源要素配置优化在数字新质生产力对城乡高质量融合的影响中起中介作用。数字新质生产力对城乡高质量融合的促进作用具有边际效应递增的非线性特征,产业结构升级、资源要素配置优化、公共服务均等化对这种非线性影响具有强化作用。数字新质生产力对城乡高质量融合的影响具有地区异质性,从线性影响看,在东部地区最强,在中部地区其次,在西部地区最弱;从非线性影响看,数字新质生产力的影响在东部和西部地区存在单一门限效应,在中部地区存在双重门限效应。为促进城乡高质量融合,应积极推动生产要素数字化转型,加快数字新质生产力形成;驱动产业结构升级,为城乡高质量融合提供动力;畅通资源要素流动渠道,优化资源要素配置;加强公共服务配套设施建设,助力公共服务均等化;结合地区特点,因地制宜培育数字新质生产力。

农村产业融合与农民共同富裕——基于田园综合体试点政策分析

在共同富裕目标下,基于政治经济学分析框架,厘清产业融合影响农民增收的理论机制,进而以田园综合体建设试点政策表征农村产业融合,构造准自然实验,并以中国1240个县域为样本进行实证分析。研究发现:(1)田园综合体试点地区的低收入群体显著增收且农民收入差距明显缩小,证明农村产业融合能带动低收入群体增收,进而促进共同富裕;(2)低收入群体的就业结构优化是农村产业融合产生共同富裕效应的主渠道;(3)农旅融合较农工融合对农民共同富裕的促进作用更强,不同群体收入水平在政策冲击后的变化也印证了这一点;(4)农村产业融合的农民共同富裕效应存在产业融合基础异质性:前期产业融合基础较弱的县域,在推进产业融合促进共同富裕方面表现出更强后发优势;强行政资源支持会增强农村产业融合的共同富裕提升效应。因此,应加大力度支持农旅融合型试点建设,优化低收入群体就业结构,依据区位与农民收入实际,选择性设立田园综合体试点,利用政策扶持推进产业融合。

基于FAPSO的地铁列车节能运行优化研究

以地铁列车节能、准点运行为研究目标,在充分考虑实际运行线路条件下,构建满足约束条件下的多质点列车运行能耗模型,并在此基础上,将萤火虫算子引入到标准粒子群算法中,构建一种包含萤火虫算子的粒子群优化算法(FAPSO),进而提出基于FAPSO算法的双层结构一体化优化控制方法。上层结构优化通过使用FAPSO算法对获得的总冗余时间进行分配,进而得出各站间最佳运行时间,优化列车运行时刻表;下层结构优化在上层结构优化所得站间最佳运行时间下,对不同运行策略下列车运行能耗进行比较,进而优化整条线路的列车运行策略。最终,获得列车站间节能、准点运行的最优驾驶方案。以广州地铁站间线路为例,通过MATLAB进行实例仿真,仿真结果表明,经双层结构一体化优化后列车运行能耗降低10.8%,且满足列车准点运行的要求。

科教融汇视域下西部高等教育结构的困境检视与功能重塑

在教育强国建设进程中,优化区域高等教育结构布局,是我国西部高等教育实现高质量发展的重要举措。科教融汇新理念的提出,为新时代西部高等教育结构优化与布局调整提供了方向指引。全面振兴西部高等教育,需坚持以科教融汇为新方向,在层次结构上凸显人才梯队培养,在科类结构上服务科技产业升级,在形式结构上形塑科研生态系统,在布局结构上优化科研资源配置。然而,在实践层面,西部高等教育当前仍面临较为突出的结构性问题,在支撑引领区域科技创新、产业升级等方面的功能尚未得到充分发挥,包括人才培养层次结构重心偏低,高科技人才缺口大;高校学科专业结构适应性差,科技驱动能力不足;形式结构内部要素协同性弱,科研合作机制不畅;优质教育资源布局结构失衡,科技创新活力不足。站在新的历史起点,在普及化初级阶段,西部高等教育应在科教融汇理念指导下,遵循整体性、协调性、适应性和开放性原则,深化科教融汇育人理念,逐步上移层次结构重心;立足科技产业发展需要,动态调整学科专业结构;推动西部高校集群发展,促进形式结构协同联动;加强科技创新开放合作,完善科研设施布局结构。

“三合一”自建房结构安全智能预警模型

“三合一”自建房虽便于业主生产、储存、经营活动,但因其功能复合,其结构安全性常存在较多严重的问题。为提前预警此类建筑的安全隐患,本研究基于机器学习算法构建了“三合一”自建房结构安全预警模型,并先后应用集成思想和智能优化算法,对预警性能进行了2次提升。首先,采用独热编码、过采样等方法对某地获取的数据进行预处理;其次,选择总体准确率、召回率和AUC值3项指标分别选出最佳的基分类器;之后,使用袋装法和提升法等集成思想优化预警模型的性能;然后,应用鲸鱼、金豺、粒子群等智能优化算法对预警模型性能进一步优化;最后,综合以上模型运算结果,挖掘预警指标中的关键指标。结果表明:(1)经鲸鱼算法优化的Bagging(KNN)模型可更高效地对“三合一”自建房的结构安全进行预警,其召回率为0.802;(2)经鲸鱼算法优化的Boosting(SVM)模型具有更稳定的预警鲁棒性,其AUC值为0.933;(3)默认参数的XGB模型整体预警效率更佳,其总体准确率为0.915;(4)建筑年份、砖混结构、地上层数、建筑面积等14个指标是“三合一”自建房结构安全预警的关键指标。

整体齿啮式快开门高压釜应力分析及结构优化

采用ANSYS有限元分析技术,建立整体齿啮式快开结构的有限元模型,对其进行结构强度分析和疲劳寿命评价。同时,以结构总质量为目标函数,对高压釜的快开密封结构进行优化分析。选取卡箍上环齿厚度T1、平盖封头齿厚度T2、卡箍筒体厚度T3、卡箍上环齿长度L1、平盖封头齿长度L2这5组变量作为设计变量,最大应力值、最大位移值、快开门结构总质量作为因变量,通过轻量化分析,得到优化后的快开门质量为2 921.9 kg,比优化前降低了16.5%。