基于改进Funnel控制的机械臂轨迹跟踪约束控制

针对关节柔性机械臂系统在未知输入饱和的情况下的稳态和瞬态性能约束问题,提出一种改进Funnel控制结合RBF自适应神经网络的轨迹跟踪控制方法。设计了改进的Funnel控制变量以避免控制律中的微分不可导的情况;构造了时变的瞬态性能约束函数,调节系统输出初始阶段的超调量和收敛速度;采用最小参数学习法的RBF自适应神经网络,逼近机械臂系统模型的未知函数和虚拟控制律的导数,简化了控制器的设计;通过李雅普诺夫稳定性定理,证明了闭环系统中所有变量是半全局一致最终有界的。仿真实验验证了所提方法有效性。

带有饱和的电机伺服系统非奇异终端滑模funnel控制（英文）

本文提出一种非奇异终端滑模funnel控制(NTSMFC)方法,实现带有饱和输入电机伺服系统的指定性能跟踪控制.根据中值定理,非光滑饱和函数转化为放射形式,并且应用一个简单的神经网络进行逼近和补偿.为保证跟踪误差被限制在指定的界限内,同时为避免构建复杂的barrier李雅普诺夫函数或逆函数,本文采用一个新的限制变量.然后,构建非奇异终端滑模funnel控制器保证电机伺服系统的指定跟踪性能.该方法无需事先已知输入饱和函数的界限等先验知识,且基于李雅普诺夫函数设计可以保证位置跟踪误差的收敛性,最后给出仿真对比实例证明了该方法的有效性.

Conditions Supporting Funnel Cloud Development in Alaska

The characteristics and climatology of funnel clouds in Alaska were examined using operational radiosondes, surface meteorological observations, and reanalysis data. Funnel clouds occurred under weak synoptic forcing between May and September between 11 am and 6 pm Alaska Daylight Time with a maximum occurrence in July. They occurred under Convective Available Potential Energy >500 J·kg-1 and strong low-level wind shear. Characteristic atmospheric profiles during funnel cloud events served to develop a retrieval algorithm based on similarity testing. Out of more than 129,000 soundings between 1971 and 2014, 2724, 442, and 744 profiles were similar to the profiles of observed funnel cloud events in the Interior, Alaska West Coast, and Anchorage regions. While the number of reported funnel clouds has increased since 2000, the frequency of synoptic situations favorable for such events has decreased.

基于未知系统动态估计器的柔性关节机械臂funnel控制

针对带有模型不确定和外部干扰的柔性关节机械臂,提出一种基于未知系统动态估计器的funnel控制方法。基于低通滤波器设计未知系统动态估计器,用于估计模型不确定和外部干扰,该估计器结构简单,仅有一个可调参数。构造带有时变约束边界的新型funnel变量,保证系统跟踪误差被限制在预先设定的边界内,进而改善系统瞬态性能。在此基础上,设计反演控制器,保证系统输出快速准确跟踪期望轨迹。为避免传统反演法中的“微分爆炸”问题,设计跟踪微分器逼近虚拟控制律导数。并给出数值仿真对比验证本文所提方法的有效性。

多电机驱动系统的保性能鲁棒Funnel控制

本文针对含参数不确定性的多电机驱动系统,提出一种基于最优保性能鲁棒的Funnel控制方法实现系统的规定跟踪性能.该控制方法通过构造Funnel函数对误差系统进行变换,并设计自适应反步控制器保证变换后系统的稳定性即可使跟踪误差的瞬态和稳态响应均被限制在给定的Funnel边界内.然而由于系统中存在的参数不确定性会影响系统的规定控制性能,本文在Funnel控制基础上又设计了最优保性能鲁棒控制器.它是通过将参数不确定性系统的保性能鲁棒控制问题转化为标称系统的最优控制问题,并求解新的黎卡提方程而得到的.因此所设计的控制器不但消除了参数不确定性对系统的影响并且能够使系统的性能指标达到一确定的上界.最后,对四电机驱动系统进行了仿真和实验验证,说明所提出控制方法的有效性.

输入时滞非线性系统的新型动态面Funnel控制

本文针对一类带有输入时滞的不确定非线性系统,提出了新型动态面Funnel控制方案.首先设计补偿动态变量将输入时滞系统转换成无时滞的系统,仅需在递归控制的最后一步补偿,从而优化了控制器设计过程.其次,构造Funnel函数,使系统的瞬态和稳态跟踪误差被限制在给定边界内.最后,提出新型非线性动态面控制方法,不仅避免了自适应反推控制中的“微分爆炸”问题,而且消除了边界层误差,使得系统的跟踪误差最终渐近收敛到零.理论分析表明该闭环系统的所有信号一致最终有界,仿真结果验证了该控制方案的有效性.

Corrosion mechanism of magnesia-chromite refractories by ZnO-containing fayalite slags: Effect of funnel glass addition

An efficient approach for lead extraction from waste funnel glass through the lead smelting process has been proposed. To clarify the effect of funnel glass addition on the degradation of magnesia-chromite refractories by ZnO-containing fayalite slag, the corrosion behavior of magnesia-chromite refractories in lead smelting slags with different funnel glass additions from 0wt% to 40wt% was tested. Scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS) was used to acquire the microstructural information of the worn refractory samples. Experimental results showed that the corrosion of magnesia-chromite refractory consisted predominantly of the dissolution of MgO into slag. ZnO and FeO reacted with periclase and chromite to form (Zn,Fe,Mg)O solid solution and (Zn,Fe,Mg)(Fe,Al,Cr)2O4 spinel, respectively. With the addition of funnel glass, the solubility of MgO increased whereas ZnO levels remained stable, thereby resulting in a reduced Mg content and an elevated Zn and Fe content in the (Zn,Fe,Mg)O solid solution and the (Zn,Fe,Mg)(Fe,Al,Cr)2O4 spinel. Considering the stability of the (Zn,Fe,Mg)O solid solution layer and the penetration depth of the slag, the optimal funnel glass addition for lead smelting was found to be 20wt%.

INFLUENCES OF CASTING SPEED AND SEN DEPTH ON FLUID FLOW IN THE FUNNEL TYPE MOLD OF A THIN SLAB CASTER

In recent years, thin slab continuous casting technology has been widely used to improve the quality of the product and to reduce the cost. One of the challenges faced by this technology is to design reasonable flow patterns, which strongly affect the surface and inner properties of the final slab in the mold. With the fixed scales and complex geometrical structures of nozzle and funnel type mold, a series of numerical simulations are made to analyze the flow patterns in melt steel using finite volume method based on structured body fitted coordinate grids. The CFD （computational fluid dynamics） package is validated first using one typical case described in previously published studies, and then it is developed to study the effect of operational parameters on fluid flow in thin slab caster. Two operational parameters, casting speed and SEN （submerged entry nozzle） depth, are mainly considered for numerical analysis. On the basis of present simulations, the reasonable SEN submergence depths corresponding to different casting speeds are suggested according to fluid flow characteristics like, flow jet impingement on the narrow side of the mold, flow speed of the melt steel beneath the meniscus and the recirculation region. This is the first stage of study on the numerical analysis of the whole thin slab casting process with electromagnetic brake.

Research on numerical simulation of the groundwater funnels restoration in Shijiazhuang

In order to simulate the recovery of groundwater funnels under the condition of reducing groundwater abstraction, hydrogeological conditions of recoverability construction of Shijiazhuang groundwater funnel were analyzed, and a numerical simulation method was used based on the change of various parameters. The results show that the groundwater flow model can accurately reflect groundwater hydrogeological characteristics, and can guarantee the reliability of groundwater restoration prediction. The research has set up four schemes for rural water-saving, planting structure adjustment, urban reducing abstraction and integrated method. The effect of four restoration schemes on the restoration of groundwater funnels was compared with water table variations of two observation well. Comparison results show that the level changes of plan Three and Four are different from the other two kinds of exploitation and the drop trend of water table in the funnel area is flat. So we can conclude that Plan Three and Four have significant effect on the groundwater funnel restoration of Shijiazhuang.

Spatial-temporal Characteristics of Land Subsidence Corresponding to Dynamic Groundwater Funnel in Beijing Municipality,China

Due to long-term over-exploitation of groundwater in Beijing Municipality,regional groundwater funnels have formed and land subsidence has been induced.By combining a groundwater monitoring network,GPS monitor-ing network data,radar satellite SAR data,GIS and other new technologies,a coupled process model based on the dy-namic variation of groundwater and the deformation response of land subsidence has been established.The dynamic variation of groundwater funnels and the land subsidence response process were analyzed systematically in Beijing.Study results indicate that current groundwater funnel areas are distributed mainly in the southwest of Shunyi District,the northeast of Chaoyang District and the northwest of Tongzhou District,with an average decline rate of groundwa-ter level of 2.66 m/yr and a maximum of 3.82 m/yr in the center of the funnels.Seasonal and interannual differences exist in the response model of land subsidence to groundwater funnels with uneven spatial and temporal distribution,where the maximum land subsidence rate was about-41.08 mm/yr and the area with a subsidence rate greater than 30 mm/yr was about 1637.29 km2.Although a consistency was revealed to exist between a groundwater funnel and the spatial distribution characteristics of the corresponding land subsidence funnel,this consistency was not perfect.The results showed that the response model of land subsidence to the dynamic variation of groundwater was more revealing when combining conventional technologies with InSAR,GIS,GPS,providing a new strategy for environmental and hydrogeological research and a scientific basis for regional land subsidence control.

Dynamics of an Ultracold Bose Gas in Funnel-Shaped Potential

In this paper we develop a variational theory to study the dynamic properties of ultracold Bose gas ina funnel external potential.We obtain one-dimensional nonlinear equation which describes the dynamics of transversetight confined bosonic gas from three-dimension to one-dimension,and find one-dimensional s-wave scattering lengthwhich depends on the shape of transverse confining potential.If the funnel trapping potential is strong enough at zerotemperature,all transverse excitations are frozen.We find the dynamic equation which describes the Tonks-Girardeaugas and present a qualitative analysis of the experimental accessibility of the Tonks-Girardeau gas with funnel-trappedalkalic atoms.

Fault Ride-through Hybrid Controller for MMC-HVDC Transmission System via Switching Control Units Based on Bang-bang Funnel Controller

This paper proposes a fault ride-through hybrid controller(FRTHC)for modular multi-level converter based high-voltage direct current(MMC-HVDC)transmission systems.The FRTHC comprises four loops of cascading switching control units(SCUs).Each SCU switches between a bang-bang funnel controller(BBFC)and proportional-integral(PI)control loop according to a state-dependent switching law.The BBFC can utilize the full control capability of each control loop using three-value control signals with the maximum available magnitude.A state-dependent switching law is designed for each SCU to guarantee its structural stability.Simulation studies are conducted to verify the superior fault ride-through capability of the MMC-HVDC transmission system controlled by FRTHC,in comparison to that controlled by a vector controller(VC)and a VC with DC voltage droop control(VDRC).

基于漏斗函数双电机伺服系统跟踪与同步控制

针对双电机驱动伺服系统具有未知非线性的问题,提出一种基于漏斗函数的跟踪与同步控制方案。首先,利用神经网络逼近和补偿复杂的非线性,在此基础上,引入滤波技术解决传统反步控制的“计算爆炸”问题,同时引入非光滑漏斗误差面确保系统的状态量被约束在预定义的漏斗边界内,结合改进的漏斗函数和反步设计技术设计了一种自适应量化漏斗跟踪控制方案。为了同时保证双电机的同步运行,同步控制器采用了平均偏差耦合策略,实现了双电机伺服系统的跟踪与同步控制。仿真结果表明,该方法可以实现对负载的跟踪以及双电机的同步。

基于SwinT-YOLOX模型的自动扶梯行人安全检测算法

自动扶梯被广泛应用在公共场合,乘客摔倒事故如果不能被及时发现并处理,会造成严重的人身伤害,因此实现自动扶梯智能化监控管理势在必行。受自动扶梯运行环境复杂、行人多以及局部遮挡情况的影响,传统的人体姿态特征摔倒检测模型效果不佳且检测速度减慢。融合Swin Transformer和YOLOX目标检测算法的优秀策略,提出一种基于SwinT-YOLOX网络模型的自动扶梯行人摔倒检测算法。采用Swin Transformer模型作为骨干网络,颈部网络使用添加注意力机制的YOLOX模型,进一步提升特征图的多样性和表达能力。此外,利用漏斗修正线性单元视觉激活函数构建CBF模块,改进颈部网络和Head网络结构,从而获得更优的特征检测性能。实验结果表明,针对自建扶梯行人摔倒数据库和网络采集实际扶梯行人摔倒事故,与AlphaPose、OpenPose、YOLOv5等算法相比,该算法检测性能明显提高,行人摔倒平均检测精度可以达到95.92%,检测帧率为24.08帧/s,能够快速、精准地检测到乘客摔倒事故发生,监控管理平台立刻采取安全急停措施以保证乘客安全。

玻璃分相联用机械化学法脱除废旧含铅玻璃中重金属铅

传统分相法采用热酸浸提工艺脱除CRT锥玻璃分相产物中重金属铅,酸浸过程强酸消耗量大,废酸无法回用,易引发酸污染。目的 为了绿色、高效回收CRT锥玻璃分相产物中重金属铅,方法 采用乙二胺四乙酸(EDTA)作为浸提剂,通过机械化学法研究锥玻璃中重金属在快速分相和机械活化浸出过程中的迁移转化规律,揭示影响重金属脱除率的主要因素和作用机制。结果 结果表明:在分相处理过程中锥玻璃所含Pb,K,Ca等元素主要富集在呈连通结构的富B_(2)O_(3)相中。在随后湿法球磨浸提过程中,分相产物中富B_(2)O_(3)相在机械活化作用下快速溶解到水中,同时富B_(2)O_(3)相中所含金属离子与EDTA形成可溶络合物,且可从分相产物中脱除。锥玻璃所含Pb,K,Ca等金属脱除率随EDTA添加量增大、球磨转速提高、球磨时间延长等不断提升,但随液固比增大呈先升高后降低趋势。当EDTA添加量(质量分数,下同)为80%,球磨转速500 rpm,液固比0.8时,球磨处理30 min,分相产物中Pb,K,Ca,Al脱除率分别达到98.79%,94.92%,95.17%,65.71%,获得SiO_(2)质量分数超过92%的高硅氧玻璃粉末。结论 研究结果可为含重金属玻璃绿色、高附加值利用提供借鉴与参考。

正态漏斗附近水沙数值模拟

针对水库淤积问题,设计了一种正态漏斗排沙装置,在水槽中开展水流试验。对正态漏斗附近水流-泥沙进行欧拉两相流模拟,用水流试验数据对数值模型进行验证,进而分析了不同边界条件下流速、涡量和相浓度场。结果表明,漏斗内部流速梯度较大,泥沙相浓度等值线呈V型不对称分布,漏斗前缘、左后侧和右后侧出现大涡量区。与锥形漏斗对比,正态漏斗近壁面流速大,水流阻力小,3种边界条件下平均涡量减小25.8%~27.2%,出口泥沙相浓度增大15.2%~16.5%,具有降低能量耗散、显著提高排沙效率的作用。

探究多螺旋CT联合HMGB1检测在儿童先天性胸廓畸形中诊断价值

目的探究多螺旋CT联合HMGB1检测在儿童先天性胸廓畸形中诊断价值。方法选取2021年3月~2023年3月于我院就诊的57例疑似胸廓畸形患儿作为研究对象,以手术诊断为“金标准”,将确诊为胸廓畸形的43例患儿作为观察组,其余14例非胸廓畸形患儿作为对照组。分别检测观察组与对照组血清HMGB1水平。观察组患儿进行MSCT扫描检查,记录其CT相关数据。比较基础资料、不同亚型、不同急性严重程度之间CT相关数据及血清HMGB1水平;比较MSCT扫描、血清HMGB1水平检测及二者联合对先天性漏斗胸的检出率及诊断价值。结果对照组与观察组患儿性别、年龄、BMI方面比较无明显差异(P>0.05),观察组患儿血清HMGB1水平明显高于对照组(P<0.05)。不同亚型漏斗胸患儿Hailer指数、心脏旋转角、胸骨凹陷深度、CT凹陷指数、胸骨凹陷角度、血清HMGB1水平比较,无明显差别(P>0.05)。轻度漏斗胸患儿Hailer指数、心脏旋转角、胸骨凹陷深度、CT凹陷指数、血清HMGB1水平均低于中度、重度漏斗胸患儿,胸骨凹陷角度高于中度、重度漏斗胸患儿(P<0.05);中度漏斗胸患儿Hailer指数、心脏旋转角、胸骨凹陷深度、CT凹陷指数、血清HMGB1水平低于重度漏斗胸患儿,胸骨凹陷角度高于重度漏斗胸患儿(P<0.05)。MSCT联合HMGB1检测漏斗胸检出率是90.70%,远高于MSCT扫描的69.77%、血清HMGB1水平检测的41.86%(P<0.05)。ROC曲线分析MSCT扫描、血清HMGB1、二者联合检测对先天性漏斗胸灵敏度及特异度分析发现,二者联合检测的灵敏度、特异性及AUC均高于MSCT扫描及血清HMGB1。结论MSCT联合HMGB1检测能高效诊断出儿童先天性胸廓畸形,具有较高诊断价值。

基于购买漏斗模型的多渠道网络广告效应研究

从企业发起渠道(firm-initiated contacts,FICs)和客户发起渠道(customer-initiated contacts,CICs)两方面,探讨了不同网络广告的短期及长期效应。通过对网络广告短期效应和长期效应的综合测评,以期为企业营销合理分配广告预算提供实践指导。实证研究发现,从短期来看,FICs品牌型广告的即时效应最大,从长期来看,FICs广告有着最强的长期累积效应,特别是短信广告。FICs广告的效应持续时间比CICs广告的效应持续时间更长。CICs品牌型搜索广告在首页访问阶段产生了更高的效应,CICs通用型搜索广告在主页访问和详情页访问阶段的效应较为相近,而FICs广告能更有效地吸引客户转到特定的产品详情页面。