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Robust Distributed Model Predictive Control for Formation Tracking of Nonholonomic Vehicles

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IEEE/CAA Journal of Automatica Sinica 2024年第2期11卷 560-562页

作者： Zhigang Luo Bing Zhu Jianying zheng zewei zheng School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China

Dear Editor,This letter proposes a robust distributed model predictive control(MPC) strategy for formation tracking of a group of wheeled vehicles subject to constraints and disturbances. Formation control has attract... 详细信息

关键词： letter constraints searching

Preparation and Photostriction Properties of BiFeO_(3)-BaTiO_(3)Ceramics

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Journal of Wuhan University of Technology(Materials Science) 2024年第5期39卷 1079-1086页

作者： zheng zewei ZHANG Liqiang CHEN Chen CAO Minghe YI Zhiguo LIU Hanxing School of Materials Science and Engineering Wuhan University of TechnologyWuhan 430070China State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050China School of Microelectronics Shanghai UniversityShanghai 200444China International School of Materials Science and Engineering Wuhan University of TechnologyWuhan 430070China

Under illumination by 405,520 and 655 nm monochromatic visible light(light intensity of 30 kW/m^(2)),large photostriction(ΔL/L)of 0.19%,0.13%and 0.26%for 67BiFeO_(3)-33BaTiO_(3)(67BF-33BT)lead-free ferroelectric ceramics are obtained,*** studying the ferroelectric and photoelectric properties in conjunction with in situ Raman spectroscopy,it is found that the photostrictive effect of 67BF-33BT is not caused by the electrical strain induced by abnormal photovoltaic voltage,but related to the optical induced oxygen octahedral *** 67BF-33BT lead-free ferroelectric material with excellent photostrictive response in the visible light region is expected to play an important role in the field of optical drive electromechanical devices.

关键词： ferroelectric ceramics photostrictive effect visible light response

Spatial adaptive integral LOS path following control for an under-actuated stratospheric airship 36

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Spatial adaptive integral LOS path following control for an ...

第36届中国控制会议

作者： Ming Zhu Yangyang Song zewei zheng Wenjie Lou School of Aeronautic Science and Engineering Beihang University The Seventh Research Division School of Automation Science and Electrical EngineeringBeihang University

ISBN: (纸本)9781538629185

Extending the adaptive integral LOS path following method from planar to spatial,this paper presents a novel spatial path following control method for an under-actuated stratospheric airship in the presence of unknown *** nonlinear dynamic model of the airship is first ***,the spatial adaptive integral LOS guidance method generates the desired attitude and estimates the *** backstepping and Lyapunov-based techniques are adopted to track the predefined attitude and *** final design of the control system consists of three parts:guidance loop,attitude control loop and velocity control *** analysis demonstrates that the closed-loop control system is ultimately *** results of the typical path are proposed to illustrate the effectiveness of the proposed control method.

关键词： Stratospheric Airship Spatial Path Following Integral LOS Under-actuated

全髋关节置换后的低蛋白血症:危险因素及列线图预测模型建立

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中国组织工程研究 2025年第15期29卷 3147-3152页

作者：郑泽炜叶凯静张阔赵庆华陈秀天江禹来易艳梓张庆文广州中医药大学第三临床医学院广东省广州市510006 广州中医药大学惠州医院广东省惠州市516005 广州中医药大学第三附属医院关节中心广东省广州市510405

背景:患者接受全髋关节置换后多发低蛋白血症,影响术后愈合及康复。目的:探讨及筛选全髋关节置换后发生低蛋白血症的危险因素,建立列线图为临床中判断全髋关节置换后是否发生低蛋白血症提供指导。方法:共纳入行全髋关节置换患者355例,... 详细信息

背景:患者接受全髋关节置换后多发低蛋白血症,影响术后愈合及康复。目的:探讨及筛选全髋关节置换后发生低蛋白血症的危险因素,建立列线图为临床中判断全髋关节置换后是否发生低蛋白血症提供指导。方法:共纳入行全髋关节置换患者355例,根据术后第1天是否出现低蛋白血症分为低蛋白血症组238例、正常组117例,低蛋白血症发生率为67%。收集患者年龄、性别、糖尿病、高血压、高尿酸血症、高血脂、麻醉方式、置换前白细胞、置换前红细胞、置换前血红蛋白、置换前血小板、置换前血浆凝血酶原时间、置换前活化部分凝血酶原时间、置换前国际标准化比值、置换前凝血酶时间、置换前纤维蛋白原、置换前血沉、置换前C-反应蛋白、置换前D-二聚体、置换前平均红细胞血红蛋白含量、置换前平均红细胞体积、手术时间、体质量指数、置换前降钙素原、置换前红细胞压积等资料。利用SPSS 27.0软件进行单因素分析,随后利用R语言(4.3.1)再次对观察指标进行最小绝对收缩和选择算子回归分析及10倍交叉验证,取二者危险因素交集,使用SPSS 27.0进行多因素二元Logistic回归分析得到最终危险因素,通过R语言构建全髋关节置换后低蛋白血症的预测模型,并构建受试者特征曲线曲线、校准曲线、临床决策曲线评估预测模型预测能力。结果与结论:①经过单因素分析、最小绝对收缩和选择算子回归、多因素二元Logistic回归,筛选出年龄(OR=1.024,P=0.023)、置换前血小板(OR=0.995,P=0.028)、置换前血沉(OR=1.031,P=0.045)在判断置换后是否会发生低蛋白血症方面具有统计学意义(P<0.05);②基于多因素Logistic回归所筛选出的最终危险因素构建列线图预测模型,并通过构建受试者特征曲线评估模型预测能力,经计算受试者工作特征曲线的曲线下面积达到0.835(95%CI=0.779-0.891),C-index=0.835,经临床决策曲线计算,模型在阈值为0-0.83可带来更好的临床效能,该预测模型具有良好的灵敏度与准确性,可为医护人员及患者在全髋关节置换前更好地识别置换后发生低蛋白血症的风险。

关键词：全髋关节置换低蛋白血症危险因素预测模型列线图

Output-Constrained Point-to-Point Tracking of Underactuated Surface Vessel with Uncertainties

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Output-Constrained Point-to-Point Tracking of Underactuated ...

第37届中国控制会议

作者： Linping Ruan zewei zheng Seventh Research Division School of Automation Science and Electrical EngineeringBeihang University

This paper considers the point-to-point tracking control problem of an underactuated surface vessel（USV） with output constraints and *** controller design is based on backstepping *** Lyapunov function（BLF） is used to address the output *** addition,a radial basis function neural network（RBFNN） is constructed to provide an estimation and compensation of the unknown *** is proved that under the proposed control,the constraints will never be violated,and all closed-loop signals are *** results and comparisons illustrate the effectiveness and advantages of the proposed controller.

关键词： Barrier Lyapunov function Output constraints Point-to-point trajectory tracking Underactuated Surface Vessel

Asymmetric error-constrained path-following control of a stratospheric airship

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Asymmetric error-constrained path-following control of a str...

第37届中国控制会议

作者： Tian Chen Ming Zhu zewei zheng School of Aeronautic Science and Engineering Beihang University The Seventh Research Division School of Automation Science and Electrical EngineeringBeihang University

This paper addresses the asymmetric error-constrained vector filed path-following problem of a stratospheric airship with external *** algorithm for asymmetric error-constrained path-following of the stratospheric airship is proposed based on the theories of asymmetric barrier Lyapunov function,vector field guidance and adaptive sliding mode ***,the asymmetric vector field guidance law（AVFGL） is presented,which can navigate the stratospheric airship along the predefined path and guarantee the tracking error is limited by aysmmetric error ***,an adaptive sliding mode attitude controller is introduced to track the desired attitude caculated by the ***,an adaptive velocity controller to maintain constant velocity is added to the control *** results demonstrate the effectiveness of the proposed control algorithm.

关键词： Stratospheric Airship Path Following Control Asymmetric Error Constraints Vector Field

Nonlinear Control for Automatic Carrier Landing with Deck Motion Compensation

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Nonlinear Control for Automatic Carrier Landing with Deck Mo...

第37届中国控制会议

作者： Yunpeng Ma Zhiyuan Guan zewei zheng School of Aeronautic Science and Engineering Beihang University The Seventh Research Division School of Automation Science and Electrical EngineeringBeihang University

This paper presents a nonlinear path-following control scheme with constant angle of attack for automatic carrier landing system in final approach. Based on the six degrees-of-freedom（6-DOF） aircraft model, back-stepping technique is adopted as the main control framework. To facilitate the controller design, some transformations are made to the model. Since low speed will cause unstability during landing, a novel control scheme, which maintains a constant angle of attack, is *** angle of attack is controlled by thrust independently. In order to ensure control performance in the presence of deck motion,deck motion compensation is proposed to generate ideal glide path in real time considering two aspects: the trajectory applicable to the fixed runway, and the current state of both aircraft and carrier. Finally, the synthetic environment used for numerical validation is modeled. Simulations based on a nonlinear 6-DOF model show effectiveness of the proposed control scheme even in the presence of carrier air wake and deck motion.

关键词： Automatic carrier landing system Nonlinear Back-stepping Approach power compensation system Deck motion compensation

Image-Based Visual Servoing Control for Automatic Carrier Landing

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Image-Based Visual Servoing Control for Automatic Carrier La...

第40届中国控制会议

作者： Simin Liu zewei zheng Zhiyuan Guan Kang Lin School of Automation and Electrical Engineering Beihang University (BUAA) School of Aeronautic Science and Engineering Beihang University (BUAA)

This paper studies the control problem of automatic carrier landing for a fixed-wing aircraft through image-based visual servoing（IBVS） technology. An image-aircraft integration model is established by incorporating the virtual image feature into the aircraft dynamics. Based on the model, we established a control framework with the attitude control as inner loop and visual servoing guidance as outer loop. For trajectory instability at low speed of aircraft, the approach power compensation system with constant angle of attack is used. In order to eliminate the influence of wind turbulence, the nonlinear disturbance observer（NDO） is designed to estimate disturbance. The Lyapunov analysis proves the stability of the system, and the simulation verifies the proposed control scheme can make the aircraft track the desired trajectory and land on the carrier with good performance.

关键词： Image-Based Visual Servoing Carrier Landing Nonlinear Disturbance Observer

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非洲牧区可持续发展模式探析

南开学报（哲学社会科学版） 2022年第3期 163-172页

作者：高永久郑泽玮南开大学民族事务研究中心天津300350 南开大学周恩来政府管理学院天津300350

非洲牧区的可持续发展问题对非洲人民,乃至全世界人民的长远发展都具有重要意义。在联合国可持续发展理念中,经济价值增长、政治社会包容、生态环境保护是可持续发展的三个方面。以此为脉络梳理相关研究成果可以发现,非洲牧区可持续发... 详细信息

非洲牧区的可持续发展问题对非洲人民,乃至全世界人民的长远发展都具有重要意义。在联合国可持续发展理念中,经济价值增长、政治社会包容、生态环境保护是可持续发展的三个方面。以此为脉络梳理相关研究成果可以发现,非洲牧区可持续发展在经历了早期传统游牧的发展模式和殖民主义者对非洲牧区传统可持续发展模式的破坏之后,当代非洲牧区在可持续发展模式构建方面遇到了前所未有的风险与挑战。总结学术界的研究,在非洲牧区可持续发展的路径方面,提出了在经济价值增长层面持续推动跨国合作、在政治和社会包容层面多元主体参与牧区治理模式中更加重视牧民的意见、在生态环境保护层面依据实际情况在自然保护区边缘设置缓冲开放区域的可持续发展方案。

关键词：牧区可持续发展非洲模式