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Adaptive Trajectory Tracking Control for Nonholonomic Wheeled Mobile Robots:A Barrier Function Sliding Mode Approach

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IEEE/CAA Journal of Automatica Sinica 2024年第4期11卷 1007-1021页

作者： Yunjun Zheng Jinchuan Zheng Ke Shao Han zhao Hao Xie hai Wang the school of Mechanical engineering Hefei University of TechnologyHefei 230009China the school of Science Computing and Engineering TechnologiesSwinburne University of TechnologyHawthorn VIC 3122Australia the school of civil Aviation Northwestern Polytechnical UniversityXi’an 710072China the Shanghai aerospace Control Technology Institute Shanghai 201109 the school of Automation Science and Electrical engineering Beihang UniversityBeijing 100191China the College of Science HealthEngineering and EducationMurdoch UniversityPerth WA6150Australia

The trajectory tracking control performance of nonholonomic wheeled mobile robots(NWMRs)is subject to nonholonomic constraints,system uncertainties,and external *** paper proposes a barrier function-based adaptive sliding mode control(BFASMC)method to provide high-precision,fast-response performance and robustness for *** with the conventional adaptive sliding mode control,the proposed control strategy can guarantee that the sliding mode variables converge to a predefined neighborhood of origin with a predefined reaching time independent of the prior knowledge of the uncertainties and disturbances *** advantage of the proposed algorithm is that the control gains can be adaptively adjusted to follow the disturbances amplitudes thanks to the barrier *** benefit is that the overestimation of control gain can be eliminated,resulting in chattering ***,a modified barrier function-like control gain is employed to prevent the input saturation problem due to the physical limit of the *** stability analysis and comparative experiments demonstrate that the proposed BFASMC can ensure the prespecified convergence performance of the NWMR system output variables and strong robustness against uncertainties/disturbances.

关键词： Adaptive sliding mode barrier function nonholonomic wheeled mobile robot(NWMR) trajectory tracking control

Liutex-based vortex control with implications for cavitation suppression

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Journal of Hydrodynamics 2021年第1期33卷 74-85页

作者： Yi-qian Wang hai-dong Yu Wei-wen zhao De-cheng Wan school of Mathematical Science Soochow UniversitySuzhou 215006China school of aerospace engineering Tsinghua UniversityBeijing 100084China Computational Marine Hydrodynamics Lab(CMHL) State Key Laboratory of Ocean EngineeringSchool of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Viewed as sinews and muscles of fluid motion,coherent vortical structures with their interactions are key to understanding the flow *** upon this observation,we explore the possibility of efficient flow control by directly manipulating vortices numerically inside the flow field based on the vortex definition and identification system of *** objective is twofold:(1)to study the vortex dynamics,for example,by observing the response of the flow to strengthening or weakening of certain vortices,and(2)to obtain efficient vortex-based control strategies which might lead us to practical *** the present numerical study,the manipulating of vortices is achieved by introducing additional source(force)terms to the Navier-Stokes equations,which hereafter will be collectively called Liutex force field *** including controlling the rotation strength and centripetal force of particular vortices are detailed in a flow past a cylinder with different control purposes at Reynolds number of *** examples are provided with a cavitating flow around two-dimensional Clark-Y hydrofoil,with particular interests on cavitation *** is illustrated particular vortex with cavitation encircled could be effectively suppressed.

关键词： Vortex dynamics Liutex vector flow control cavitation Introduction

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载人潜器锥台形观察窗蠕变特性分析

哈尔滨工程大学学报 2019年第1期40卷 12-19页

作者：黄浔韩端锋刘峰赵方瑜肖凌晨孙海哈尔滨工程大学船舶工程学院黑龙江哈尔滨150001 哈尔滨工程大学核科学与技术学院黑龙江哈尔滨150001 天津大学机械工程学院天津300000 哈尔滨工程大学航天与建筑工程学院黑龙江哈尔滨150001

为了解决在载人潜器观察窗设计中可能出现的变形协调问题,本文提出了观察窗蠕变有限元分析方法,并将计算结果与文献中试验结果对比,验证了方法可信度。研究观察窗厚度-直径比、倾角和接触面摩擦系数3个重要设计参数对观察窗轴向位移和... 详细信息

为了解决在载人潜器观察窗设计中可能出现的变形协调问题,本文提出了观察窗蠕变有限元分析方法,并将计算结果与文献中试验结果对比,验证了方法可信度。研究观察窗厚度-直径比、倾角和接触面摩擦系数3个重要设计参数对观察窗轴向位移和应力的影响,开展了锥台形观察窗蠕变特性研究。结果表明:观察窗厚度-直径比、摩擦系数与目标响应呈负相关;观察窗倾角与轴向位移呈正相关,与应力基本呈正相关,局部存在极值点;厚度-直径比对目标响应影响最大。在锥台形观察窗设计和优化时,应考虑其蠕变特性,协调观察窗厚度-直径比以使其性能优化。

关键词：载人潜器锥台形观察窗蠕变接触厚度-直径比目标响应设计与优化有限元

Taking the pulse of COVID-19:a spatiotemporal perspective

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International Journal of Digital Earth 2020年第10期13卷 1186-1211页

作者： Chaowei Yang Dexuan Sha Qian Liu Yun Li hai Lan Weihe Wendy Guan Tao Hu Zhenlong Li Zhiran Zhang John Hoot Thompson Zifu Wang David Wong Shiyang Ruan Manzhu Yu Douglas Richardson Luyao Zhang Ruizhi Hou You Zhoua Cheng Zhong Yifei Tian Fayez Beaini Kyla Carte Colin Flynn Wei Liu Dieter Pfoser Shuming Bao Mei Li Haoyuan Zhang Chunbo Liu Jie Jiang Shihong Du Liang zhao Mingyue Lu Lin Li Huan Zhou Andrew Ding NSF Spatiotemporal Innovation Center George Mason Univ.FairfaxVAUSA Department of Geography and GeoInformation Science George Mason Univ.FairfaxVAUSA Department of Geographical Sciences University of MarylandCollege ParkMDUSA Center for Geographic Analysis Harvard UniversityCambridgeMAUSA Geoinformation and Big Data Research Lab Department of GeographyUniversity of South CarolinaColumbiaSCUSA Chinese Academy of Surveying and Mapping BeijingPeople’s Republic of China school of Resource and Environmental Sciences Wuhan UniversityWuhanPeople’s Republic of China Cloud Computeand Storage OperationsInformation Technology ServicesGeorge Mason UniversityFairfaxVAUSA Department of Geography Pennsylvania State UniversityState CollegePAUSA school of Business Management East China Normal UniversityShanghaiPeople’s Republic of China school of Mathematical Sciences East China Normal UniversityShanghaiPeople’s Republic of China Department of Psychology George Mason UniversityFairfaxVAUSA mDepartment of Computer Science George Mason UniversityFairfaxVAUSA Department of Information Technology George Mason UniversityFairfaxVAUSA Department of Biology George Mason UniversityFairfaxVAUSA College of Land Science and Technology China Agricultural UniversityBeijingPeople’s Republic of China china Data Institute Ann ArborMIUSA Institute of Remote Sensing and GIS Peking UniversityBeijingPeople’s Republic of China aerospace Information Research Institute Chinese Academy of SciencesBeijingPeople’s Republic of China school of Geomatics and Urban Spatial Informatics Beijing University of Civil Engineering and ArchitectureBeijingPeople’s Republic of China school of Geographical Sciences Nanjing University of Information Science&TechnologyNanjingPeople’s Republic of China school of Geodesy and Geomatics Wuhan UniversityWuhanPeople’s Republic of China wFaculty of Environment University of WaterlooWaterlooCanada

The sudden outbreak of the Coronavirus disease(COVID-19)swept across the world in early 2020,triggering the lockdowns of several billion people across many countries,including china,Spain,India,the U.K.,Italy,France,Germany,Brazil,Russia,and the *** transmission of the virus accelerated rapidly with the most confirmed cases in the U.S.,India,Russia,and *** response to this national and global emergency,the NSF Spatiotemporal Innovation Center brought together a taskforce of international researchers and assembled implementation strategies to rapidly respond to this crisis,for supporting research,saving lives,and protecting the health of global *** perspective paper presents our collective view on the global health emergency and our effort in collecting,analyzing,and sharing relevant data on global policy and government responses,human mobility,environmental impact,socioeconomical impact;in developing research capabilities and mitigation measures with global scientists,promoting collaborative research on outbreak dynamics,and reflecting on the dynamic responses from human societies.

关键词： Big Data Earth system emergency geospatial sciences epidemics applications

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表面改性促进金属抗霜性能研究

节能技术 2021年第1期39卷 15-19,25页

作者：赵海谦何明祺董明刘景雯刘晓燕东北石油大学土木建筑工程学院黑龙江大庆163000

结霜现象普遍存在于航空航天及制冷空调领域,蒸发器及其他设备表面结霜会增加传热热阻,影响运行效率,更有甚者危及生产安全。本文利用分子自组装法和气相沉积法分别在紫铜和不锈钢表面制备出了改性涂层,并对其各自的疏水性能和抗霜性能... 详细信息

结霜现象普遍存在于航空航天及制冷空调领域,蒸发器及其他设备表面结霜会增加传热热阻,影响运行效率,更有甚者危及生产安全。本文利用分子自组装法和气相沉积法分别在紫铜和不锈钢表面制备出了改性涂层,并对其各自的疏水性能和抗霜性能进行了对比研究。结果表明,正十八硫醇改性涂层和碳纳米管改性涂层最大接触角分别为149.28°和149.22°,两种改性涂层相比于传统金属材料表面结霜时间平均延长5 min和9 min,结霜量平均降低49.9%和66.9%,表现出了良好的疏水性能和抗霜性能。

关键词：表面改性疏水性能抗霜性能正十八硫醇碳纳米管