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An active high-static-low-dynamic-stiffness vibration isolator with adjustable buckling beams:theory and experiment

Applied Mathematics and Mechanics(English Edition) 2024年第3期45卷 425-440页

作者： Kefan XU Muqing NIU Yewei ZHANG Liqun CHEN School of Science Harbin Institute of TechnologyShenzhen 518055Guangdong ProvinceChina College of Aerospace Engineering Shenyang Aerospace UniversityShenyang 110136China Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai Frontier Science Center of MechanoinformaticsShanghai Institute of Applied Mathematics and MechanicsSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai 200444China Shanghai Institute of Aircraft Mechanics and Control Shanghai 200092China

High-static-low-dynamic-stiffness(HSLDS)vibration isolators with buckling beams have been widely used to isolate external *** active adjustable device composed of proportion integration(PI)active controllers and piezoelectric actuators is proposed for improving the negative stiffness stroke of buckling beams.A nonlinear output frequency response function is used to analyze the effect of the vibration *** prototype of the active HSLDS device is built,and the verification experiment is *** results show that compared with the traditional HSLDS vibration isolator,the active HSLDS device can broaden the isolation frequency bandwidth,and effectively reduce the resonant amplitude by adjusting the active control *** maximum vibration reduction rate of the active HSLDS vibration isolator can attain 89.9%,and the resonant frequency can be reduced from 31.08 Hz to 13.28 ***,this paper devotes to providing a new design scheme for enhanced HSLDS vibration isolators.

关键词： active control high-static-low-dynamic-stiffness(HSLDS) vibration isola-tor dynamic analysis

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Optimization of the Structural Parameter in Line-start Permanent Magnet Synchronous Machine for Traction Applications 26

Optimization of the Structural Parameter in Line-start Perma...

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26th International Conference on Electrical Machines and Systems, ICEMS 2023

作者： Zou, Hui Hu, Yaohua Zhu, Shushu Avic Aerospace System CO. Ltd General Management Department Beijing China Aviation Key Laboratory of Science and Technology on Aero Electromechanical System Integration Nanjing Engineering Institute of Aircraft Systems Nanjing China Nanjing University of Aeronautics and Astronautics Center for More-electric-aircraft Power System Nanjing China

ISBN: (纸本)9798350317589

This paper studied the permanent magnet arrangement methods for a 30 kVA line-start permanent magnet synchronous machine for traction applications. By comparing the magnetic flux distribution, no-load starting characteristics, and starting torque of the three structures, the V-shaped structure has the most advantages when all parameters are integrated. At the same time, the selected V-shaped rotor was optimized, such as rotor slot width, slot depth, permanent magnet structure and size. The optimal rotor slot and permanent magnet structure were compared, and the performance of the final machine was analyzed. The simulation results indicate that the machine designed in this paper has the advantages of low starting current and high efficiency. © 2023 IEEE.

关键词： Permanent magnets

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Enhancing lithium-ion and electric conductive Li_(2)FeSiO_(4)cathode through in situ boron-doping and carbon-coating strategy

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Rare Metals 2022年第12期41卷 4055-4064页

作者： Hao-Xiang Li Jia-Hui Zhu Xiao-Bing Huang Tao Zhou Yu-Rong Ren Hunan Provincial Key Laboratory of Chemical Power Sources College of Chemistry and Chemical EngineeringCentral South UniversityChangsha 410083China Hunan Provincial Key Laboratory of Water Treatment Functional Materials Hunan Provincial Key Laboratory for Control Technology of Distributed Electric Propulsion AircraftCollege of Chemistry and Materials EngineeringHunan University of Arts and ScienceChangde 415000China Jiangsu Province Engineering Research Center of Intelligent Manufacturing Technology for the New Energy Vehicle Power Battery Changzhou Key Laboratory of Intelligent Manufacturing and Advanced Technology for Power BatterySchool of Materials Science and EngineeringChangzhou UniversityChangzhou 213164China

The extremely low electrical conductivity and ion-diffusion coefficient of Li_(2)FeSiO_(4)limits its application as a cathode material in lithium-ion ***,in situ boron-doped Li_(2)FeSi_(1)-xB_(x)O_(4-δ)/C(x=0,0.01,0.03,0.05 and 0.07)at the Si site was prepared via the solid-state reaction method using pitch as the c arbon source.B doping in the lattice structure and a c arbon coating on the surface of the composites could effectively enhance the Li^(+)/electron ***,the reduced particle size of the active material with the relatively high specific area via borondoped modification could improve the wettability between the electrolyte and *** the synergistic effect of appropriate boron doping and carbon coating,it exhibits a good rate performance,specific capacity,and cycling *** a result,the as-prepared Li_(2)FeSi_(0.95)B_(0.05)O_(4-δ)/C cathode showed a high discharge capacity of 160.7mAh·g^(-1)at 0.2C,and the capacity retention rate was 96%after 100 cycles at *** work presents an effective path for designing advanced cathode materials for lithium-ion batteries.

关键词： Li_(2)FeSiO_(4) Carbon coating Boron doping Synergistic effect Lithium-ion battery

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The Real-Time Trajectory Planning of UAV Formation Transformation Based on Safety Flight Corridor 17th

The Real-Time Trajectory Planning of UAV Formation Transform...

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17th Chinese Intelligent Systems Conference, CISC 2021

作者： Wang, Guanjie Song, Kepu Zhang, Xianglun AVIC Xi’an Flight Automatic Control Research Institute Xi’an710076 China National Key Laboratory of Science and Technology on Aircraft Control Laboratory Xi’an710076 China AVIC Xi’an Aircraft Industry Group Company Ltd. Xi’an710089 China

ISBN: (纸本)9789811663277

According to different mission scenarios, realistic environment, or other reasons, UAVs ought to be transformed into the corresponding formation. When formation transformed, it is the most important thing to avoid collision among UAVs. This paper introduces the method of the real-time trajectory of the formation transformation based on safety flight corridor. At first, the formation information, formation control model and concept of safety flight corridor are introduced. Secondly, the real-time trajectory planning strategy and algorithm with collision avoidance are designed. The algorithm proof and efficiency model are analyzed. Finally, the effectiveness of UAVs formation transformation is revealed by simulation results. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Unmanned aerial vehicles (UAV)

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Forming Circle Formations of Multi-agent Systems Under Actuator Faults 5th

Forming Circle Formations of Multi-agent Systems Under Actu...

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5th Chinese Conference on Swarm Intelligence and Cooperative control, CCSICC 2021

作者： Liu, Jiajun Ru, Xinfeng Xia, Weiguo Wang, Chen China National Aeronautical Radio Electronic Research Institute and National Key Laboratory of Science and Technology on Avionics System Integration Shanghai China Key Laboratory of Intelligent Control and Optimization for Industrial Equipment of Ministry of Education and School of Control Science and Engineering Dalian University of Technology Dalian China National Engineering Research Center of Software Engineering and the State Key Laboratory of Turbulence and Complex Systems Intelligent Biomimetic Design Lab College of Engineering Peking University Beijing China

ISBN: (纸本)9789811939976

A distributed fault-tolerant formation control law is designed in this paper for multi-agent systems under external disturbances and actuator faults including time-varying loss of effectiveness faults. The initial position of each agent is already on a circle and the control purpose is to form a desired formation on this circle. Based on this local information, a distributed adaptive formation control law is designed by employing the congelation of variables method to deal with time-varying actuator faults. Finally, a simulation example is given to verify the effectiveness of the adaptive fault-tolerant control design method. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Multi agent systems

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Dubins-A∗: A New Global Path Planning Scheme for Fixed-Wing UAV with Irregular Obstacles Avoidance

Dubins-A∗: A New Global Path Planning Scheme for Fixed-Wing...

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7th International Conference on Electronics technology, ICET 2024

作者： Xu, Junyi Shi, Mengji Tang, Fan Sun, Xinyu Yue, Jiangfeng Lin, Boxian Qin, Kaiyu University of Electronic Science and Technology of China School of Aeronautics and Astronautics Chengdu611731 China The Aircraft Swarm Intelligent Sensing and Cooperative Control Key Laboratory of Sichuan Province Chengdu611731 China National Laboratory on Adaptive Optics Chengdu610209 China

ISBN: (纸本)9798350363951

Path planning for a fixed-wing unmanned aerial vehicles (UAV) in irregular obstacle environments is a complex problem that requires consideration of the kinematic constraints of the UAV, the shape and distribution of obstacles, and the safety and efficiency of flight. With this in mind, this paper presents a new global path planning algorithm Dubins-A∗ for fixed-wing UAV based on Dubins curves and the A∗ algorithm. Firstly, an obstacle avoidance path generation algorithm, termed Dubins-avoid which utilizes Dubins curves to navigate around arbitrary polygonal obstacles, is designed. Subsequently, global path planning is executed using the path generated by the Dubins-avoid algorithm in conjunction with the A∗ algorithm's search strategy. To enhance robustness, a backtracking mechanism is incorporated to circumvent local minima, alongside an updating node mechanism designed to decrease the number of explored nodes. The effectiveness and superiority of the DubinsA* algorithm are demonstrated through testing in three distinct scenarios. © 2024 IEEE.

关键词： Unmanned aerial vehicles (UAV)

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Global Stability of a Viral Infection Model with Defectively Infected Cells and Latent Age

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Chinese Annals of Mathematics,Series B 2024年第4期45卷 555-572页

作者： Jianquan LI Yuming CHEN Peijun ZHANG Dian ZHANG School of Computer Science Xijing UniversityXi’an 710123China Department of Mathematics Wilfrid Laurier UniversityWaterlooON N2L 3C5Canada Corresponding author.Xi’an Key Laboratory of Human-Machine Integration and Control Technology for Intelligent Rehabilitation Xijing UniversityXi’an 710123China Equal contributor.Department of Immunology Xi’an Medical UniversityXi’an 710021China

The authors propose and analyze a viral infection model with defectively infected cells and age of the latently infected *** existence of steady states is determined by the basic reproduction number of *** the Lyapunov's direct method,they establish a threshold dynamics of the model with the basic reproduction number of virus as the threshold *** achieve it,a novel procedure is *** novelties are *** one hand,the coefficients involved in the specific forms of the used Lyapunov functionals for the two feasible steady states are determined by the same set of *** the other hand,for the infection steady state,a new approach is proposed to check whether the derivative of the Lyapunov functional candidate along solutions is negative(semi-)definite or *** procedure not only simplifies the analysis but also exhibits the relationship between the two Lyapunov functionals for the two feasible steady ***,the procedure is expected to be applicable for other similar models.

关键词： Viral infection model Basic reproduction number Equilibrium Global stability Lyapunov direct method Age structure

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MODELING AND ANALYSIS OF ELECTRO-HYDROSTATIC ACTUATORS EFFICIENCY 34th

MODELING AND ANALYSIS OF ELECTRO-HYDROSTATIC ACTUATORS EFFIC...

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34th Congress of the International Council of the Aeronautical Sciences, ICAS 2024

作者： Jiang, Chaofan Shang, Yaoxing Yu, Tian Liu, Zhicheng Li, Mingyang School of Automation Science and Electrical Engineering Beihang University Beijing China National Key Laboratory of Aircraft Integrated Flight Control Beihang University Beijing China Ningbo Institute of Technology Beihang University Ningbo China Tianmushan Laboratory Yuhang District Xixi Octagon City Hangzhou China

Electro-hydrostatic Actuator (EHA) is an important part which is used to control the control surface of aircraft. EHA has the advantage of higher efficiency compared with traditional hydraulic system. Compared with the hydraulic actuator, EHA adds motor, hydraulic pump, booster tank and other components. Therefore, the calculation of EHA efficiency is also more complex than that of hydraulic actuators. After research and analysis, the efficiency of wet motor-pump is low under large load or high speed. Using a passive load-sensitive EHA configuration can improve this situation. The motor copper loss can be reduced by reducing the displacement of piston pump under large load. But the displacement cannot be reduced blindly, which will lead to dynamic decline. The influence of displacement change velocity on dynamic and energy loss was studied. The effects of load sensitive variable displacement mechanism parameters such as piston area, spring stiffness, radius of damping hole and initial pressure on the velocity of displacement change were studied. The influence of parameters on dynamics and energy loss is obtained. So in order to balance efficiency and dynamics, particle swarm optimization method is adopted. Piston area, spring stiffness, radius of damping hole and initial pressure of variable displacement are taken as optimization variables. Energy loss and step response risetime are taken as optimization objectives. The energy loss and risetime are kept at a low level by obtaining appropriate load sensing mechanism parameters. The results show that the passive load sensing mechanism parameters obtained by particle swarm optimization algorithm can reduce the energy consumption of EHA under large load conditions and improve the efficiency of EHA without reducing the dynamic of EHA. © 2024, International Council of the Aeronautical Sciences. All rights reserved.

关键词： aircraft hydraulic systems

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Simulation research for flap skew on a certain type of aircraft

Simulation research for flap skew on a certain type of aircr...

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CSAA/IET International Conference on aircraft Utility Systems (AUS 2024)

作者： Xianyu Wang State Key Laboratory of Airliner Integration Technology and Flight Simulation COMAC Shanghai Aircraft Design and Research Institute Shanghai People's Republic of China

ISBN: (数字)9781837242108

This paper describes the different kinds of flap skew malfunctions and principles of flap skew sensor monitoring on an aircraft. Taking a certain type of aircraft as an example, a flap system model is established by Simulink platform. Based on this model, the skew malfunctions can be simulated. The simulation results show that the established flap system model is effective, which lays a foundation for further research.

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High-dimensional aerodynamic data modeling using a machine learning method based on a convolutional neural network

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Advances in Aerodynamics 2022年第1期4卷 845-875页

作者： Bo-Wen Zan Zhong-Hua Han Chen-Zhou Xu Ming-Qi Liu Wen-Zheng Wang Institute of Aerodynamic and Multidisciplinary Design Optimization National Key Laboratory of Science and Technology On Aerodynamic Design and ResearchSchool of AeronauticsNorthwestern Polytechnical UniversityXi’an710072China Aircraft Swarm Intelligent Sensing and Cooperative Control Key Laboratory of Sichuan Province School of Aeronautics and AstronauticsUniversity of Electronic Science and Technology of ChinaChengdu611731China

Modeling high-dimensional aerodynamic data presents a significant challenge in aero-loads prediction, aerodynamic shape optimization, flight control, and simulation. This article develops a machine learning approach based on a convolutional neural network (CNN) to address this problem. A CNN can implicitly distill features underlying the data. The number of parameters to be trained can be significantly reduced because of its local connectivity and parameter-sharing properties, which is favorable for solving high-dimensional problems in which the training cost can be prohibitive. A hypersonic wing similar to the Sanger aerospace plane carrier wing is employed as the test case to demonstrate the CNN-based modeling method. First, the wing is parameterized by the free-form deformation method, and 109 variables incorporating flight status and aerodynamic shape variables are defined as model input. Second, more than 7000 sample points generated by the Latin hypercube sampling method are evaluated by performing computational fluid dynamics simulations using a Reynolds-averaged Navier-Stokes flow solver to obtain an aerodynamic database, and a CNN model is built based on the observed data. Finally, the well-trained CNN model considering both flight status and shape variables is applied to aerodynamic shape optimization to demonstrate its capability to achieve fast optimization at multiple flight statuses.

关键词： Aerodynamic data modeling High-dimensional problem Machine learning Convolutional neural network Computational fluid dynamics

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