检索结果-内蒙古大学图书馆

design of Energy-Efficient Satellite Transfer Trajectories to Asteroids Using FTLE Fields in the HR3BP

Advances in Space Research 2025年

作者： Tianji Chen Jun Jiang Xiaoyi Wang School of Astronautics Key Laboratory of Spacecraft Design Optimization and Dynamic Simulation Technology (Ministry of Education) Beihang University Beijing 100191 China Chinese Society of Astronautics Beijing 100048 China

Asteroid flybys near Earth pose significant risks of potential impacts on Earth while simultaneously offering valuable opportunities for exploration missions. This study investigates the dynamics of a satellite transferring from Earth to an asteroid during a flyby, modeled by the Hyperbolic Restricted Three-Body Problem (HR3BP). Previous research has mainly focused on the dynamical behaviors of boundary manifolds in the HR3BP. However, boundary manifolds only exist in theoretical and radical situations and cannot be applied to the satellite trajectory design. To address this limitation, this work proposes a novel approach for satellite transfer trajectories to an asteroid by developing the applications of Finite-Time Lyapunov Exponent (FTLE) fields. By applying the method of FTLE fields, one of the libration points, the L 1 point, is proven to hold the property of an energy-efficient transfer window in the HR3BP. Then, transfer trajectories to an asteroid are generated and patched with multiple trajectories to achieve lower energy cost transfer from Earth to the asteroid than before. Numerical simulations indicate that the proposed approach reduces the energy cost of transfer trajectories by 23 % compared to the conventional Hohmann transfer approach. Additionally, to expedite the generation of FTLE fields, this study integrates the differential algebra (DA) method to reduce the generation time for FTLE fields to approximately 11 % of the time required without the DA.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Physics-Informed Neural Networks for Solving Forward and Inverse Vlasov-Poisson Equation Via Fully Kinetic simulation

SSRN

引用

SSRN 2022年

作者： Zhang, Baiyi Cai, Guobiao Weng, Huiyan Wang, Weizong Liu, Lihui Zheng, Juntao He, Bijiao School of Astronautics Beihang University Beijing100191 China Key Laboratory of Spacecraft Design Optimization and Dynamic Simulation Technologies Ministry of Education Beijing100191 China Aircraft and Propulsion Laboratory Ningbo Institute of Technology Beihang University Ningbo315832 China Baidu Inc. Beijing100094 China

The Vlasov-Poisson equation is one of the most fundamental models in plasma physics. It has been widely used in areas such as confined plasmas in thermonuclear research and space plasmas in planetary magnetospheres. In this study, we explore the feasibility of the physics-informed neural networks for solving forward and inverse Vlasov-Poisson equation (PINN-Vlasov). The PINN-Vlasov method employs a multilayer perceptron (MLP) to represent the solution of the Vlasov-Poisson equation. The training dataset comprises the randomly sampled time, space, and velocity coordinates and the corresponding distribution function. We generate training data using the fully kinetic PIC simulation rather than the analytical solution to the Vlasov-Poisson equation to eliminate the correlation between data and equations. The Vlasov equation and Poisson equation are concurrently integrated into the PINN-Vlasov framework using automatic differentiation and the trapezoidal rule, respectively. By minimizing the residuals between the predicted distribution function and labeled data, and the physically constrained residuals of the Vlasov-Poisson equation, the PINN-Vlasov method is capable of dealing with both forward and inverse problems. For forward problems, the PINN-Vlasov method can solve the Vlasov-Poisson equation accurately and more efficiently with given initial and boundary conditions than the traditional method. For inverse problems, the completely unknown electric field, initial and boundary conditions, and equation coefficients can be accurately predicted with the PINN-Vlasov method using only little particle distribution data. © 2022, The Authors. All rights reserved.

关键词： Inverse problems

来源：评论

学校读者我要写书评

暂无评论

design and fabrication of a full elastic sub-micron-Newton scale thrust measurement system for plasma micro thrusters

引用

Plasma Science and technology 2021年第10期23卷 29-39页

作者： Zhongkai Zhang Guanrong Hang Jiayun Qi Zun Zhang Zhe Zhang Jiubin Liu Wenjiang Yang Haibin Tang School of Space and Environment Beihang UniversityBeijing 100191People's Republic of China Shanghai Institute of Space Propulsion Shanghai Engineering Research Center of Space EngineShanghai 201112People's Republic of China School of Astronautics Beihang UniversityBeijing 100191People's Republic of China The Institute of Space Systems University of StuttgartStuttgart D-70569GermanyBeijing 100083People's Republic of China Key Laboratory of Spacecraft Design Optimization&Dynamic Simulation Technologies Ministry of EducationBeijing 100083People's Republic of China Laboratory of Space Environment Monitoring and Information Processing Ministry of Industry and Information TechnologyBeijing 100083People’s Republic of China

In this work,a force measurement system is proposed to measure the thrust of plasma microthruster with thrust magnitude ranging from sub-micro-Newtons to hundreds *** thrust measurement system uses an elastic torsional pendulum structure with a capacitance sensor to measure the displacement,which can reflect the position change caused by the applied force perpendicular to the pendulum *** the open-loop mode,the steady-state thrust or the impulse of the plasma micro-thruster can be obtained from the swing of the pendulum,and in the closed-loop mode the steady-state thrust can be obtained from the feedback force that keeps the pendulum at a specific *** thrust respond of the system was calibrated using an electrostatic weak force generation *** results show that the system can measure a thrust range from 0 to 200μN in both open-loop mode and closed-loop mode with a thrust resolution of 0.1μN,and the system can response to a pulse bit at the magnitude of 0.1 m N s generated by a micro cathode arc *** background noise of the closed-loop mode is lower than that of the open-loop mode,both less than 0.1 m N/Hz in the range of 10 mHz to 5 Hz.

关键词： plasma thruster micro-thrust measurement torsional pendulum

来源：评论

学校读者我要写书评

暂无评论

Bearing Failure optimization of Composite Double-Lap Bolted Joints Based on a Three-Step Strategy Marked By Feasible Region Reduction and Model Decoupling

引用

Computers, Materials & Continua 2020年第2期62卷 977-999页

作者： Fengrui Liu Wanting Yao Xinhong Shi Libin Zhao Jianyu Zhang School of Astronautics Beihang UniversityBeijing100191China Key Laboratory of Spacecraft Design Optimization and Dynamic Simulation Technologies Ministry of EducationBeihang UniversityBeijing100191China State Key Laboratory for Strength and Vibration of Mechanical Structures Xi’an Jiaotong UniversityXi’an710049China Institute of Solid Mechanics Beihang UniversityBeijing100191China College of Aerospace Engineering Chongqing UniversityChongqing400044China

To minimize the mass and increase the bearing failure load of composite double-lap bolted joints,a three-step optimization strategy including feasible region reduction,optimization model decoupling and optimization was *** feasible region reduction,the dimensions of the feasible design region were reduced by selecting dominant design variables from numerous multilevel parameters by sensitivity analyses,and the feasible regions of variables were reduced by influence mechanism *** model decoupling,the optimization model with a large number of variables was divided into various sub-models with fewer variables by variance *** the third step,the optimization sub-models were solved one by one using a genetic algorithm,and the modified characteristic curve method was adopted as the failure prediction *** on the proposed optimization method,optimization of a double-lap single-bolt joint was performed using the ANSYS®*** results show that the bearing failure load increased by 13.5%and that the mass decreased by 8.7%compared with those of the initial design of the joint,which validated the effectiveness of the three-step optimization strategy.

关键词： Composite bolted joints sensitivity analysis optimization

来源：评论

学校读者我要写书评

暂无评论

A simple artificial neural network for fire detection using landsat-8 data 24

A simple artificial neural network for fire detection using ...

引用

2020 24th ISPRS Congress - Technical Commission III

作者： Liu, Z. Wu, K. Jiang, R. Zhang, H. Department of Aerospace Information Engineering School of Astronautics Beihang University Beijing102206 China Beijing Key Laboratory of Digital Media Beijing102206 China Key Laboratory of Spacecraft Design Optimization and Dynamic Simulation Technologies Ministry of Education Beijing102206 China

Fixed threshold models have been widely used in active fire detection products. However, its accuracy is limited due to the complexity of setting up thresholds. Artificial neural network (ANN) is capable of learning from data and can decide weights automatically. Given enough data, an ANN model is able to optimize itself and quickly find an optimal solution. In this work, a simple ANN model is implemented to classify fire pixels from Landsat-8 data. Experimental results show that our ANN model effectively achieves fire detection and performs better than fixed threshold model in certain circumstances. © 2020 International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives.

关键词： Landsat

来源：评论

学校读者我要写书评

暂无评论

MOVING SHIP DETECTION and MOVEMENT PREDICTION in REMOTE SENSING VIDEOS 24

MOVING SHIP DETECTION and MOVEMENT PREDICTION in REMOTE SENS...

引用

2020 24th ISPRS Congress - Technical Commission II

作者： Wang, Y. Cheng, H. Zhou, X. Luo, W. Zhang, H. Department of Aerospace Information Engineering School of Astronautics Beihang University Beijing102206 China Beijing Key Laboratory of Digital Media Beijing102206 China Key Laboratory of Spacecraft Design Optimization and Dynamic Simulation Technologies Ministry of Education Beijing102206 China

With the rapid development of remote sensing technology, it is possible to obtain continuous video data from outer space successfully. It is of great significance in military and civilian fields to detect moving objects from the remote sensing image sequence and predict their movements. In recent years, this issue has attracted more and more attention. However, researches on moving object detection and movement prediction in high-resolution remote sensing videos are still in its infancy, which is worthy of further study. In this paper, we propose a ship detection and movement prediction method based on You-Only-Look-Once (YOLO) v3 and Simple Online and Realtime Tracking (SORT). Original YOLO v3 is improved by multi-frame training to fully utilize the information of continuous frames in a fusion way. The simple and practical multiple object tracking algorithm SORT is used to recognize multiple targets detected by multi-frame YOLO v3 model and obtain their coordinates. These coordinates are fitted by the least square method to get the trajectories of multiple targets. We take the derivative of each trajectory to obtain the real-time movement direction and velocity of the detected ships. Experiments are performed on multi-spectral remote sensing images selected on Google Earth, as well as real multi-spectral remote sensing videos captured by Jilin-1 satellite. Experimental results validate the effectiveness of our method for moving ship detection and movement prediction. It shows a feasible way for efficient interpretation and information extraction of new remote sensing video data. © 2020 International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives.

关键词： Remote sensing

来源：评论

学校读者我要写书评

暂无评论

Attitude estimation via matrix Fisher distributions on SO(3) using non-unit vector measurements

引用

Automatica 2025年 179卷

作者： Shijie Wang Haichao Gui Rui Zhong School of Astronautics Shenyuan Honors College Beihang University Beijing 100191 China Embodied Intelligence Robotics Institute Beihang University Beijing 100191 China Key Laboratory of Spacecraft Design Optimization & Dynamic Simulation Technology Ministry of Education Beijing China

This note presents a novel Bayesian attitude estimator with the matrix Fisher distribution on the special orthogonal group, which can smoothly accommodate both unit and non-unit vector measurements. The posterior attitude distribution is proven to be a matrix Fisher distribution with the assumption that non-unit vector measurement errors follow the isotropic Gaussian distributions and unit vector measurements follow the von-Mises Fisher distributions. Next, a global unscented transformation is proposed to approximate the full likelihood distribution with a matrix Fisher distribution for more generic cases of vector measurement errors following the non-isotropic Gaussian distributions. Following these, a Bayesian attitude estimator with the matrix Fisher distribution is constructed. Numerical examples are then presented. The proposed estimator exhibits advantageous performance compared to the previous Bayesian estimator with the matrix Fisher distributions and the classic multiplicative extended Kalman filter in the case of non-unit vector measurements.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Cathode erosion site distributions in an applied-field magnetoplasmadynamic thruster

引用

Plasma Science and technology 2020年第9期22卷 59-65页

作者： Peng WU Yibai WANG Yong LI Baojun WANG Kaiyu ZHANG Haibin TANG Jinbin CAO School of Astronautics Beihang UniversityBeijing 100191People's Republic of China Beijng Institute of Control Engineering Beijing 100190People’s Republic of China School of Space and Environment Beihang UniversityBeijing 100191People's Republic of China Key Laboratory of Spacecraft Design Optimization&Dynamic Simulation Technologies Ministry of EducationBeijing 100083People’s Republic of China Laboratory of Space Environment Monitoring and Information Processing Ministry of Industry and Information TechnologyBeijing 100083People's Republic of China

Erosion can influence cathode life,and is thus considered to be one of the main factors limiting the application of applied-field magnetoplasmadynamic *** this paper,erosion sites on graphite cathodes are studied so as to identify the influence of applied magnetic field and the ratio of propellant mass flow rate supplied from cathode and *** experiment results show that the application of applied magnetic field can significantly reduce the erosion rate of the cathode compared to that without magnetic *** erosion sites on the cathode vary with the relative position of the convergent-divergent magnetic field,and are mainly distributed in the divergent part of the *** erosion sites on the cathodes are found to be related to the propellant *** decreasing anode mass flow rate enlarges the range of *** results are much helpful for the analysis of cathode erosion site location since they provide evidences of erosion mechanisms and point out the directions for further research.

关键词： electric propulsion applied-field magnetoplasmadynamic thruster cathode erosion magnetic field propellant mass flow rate

来源：评论

学校读者我要写书评

暂无评论

Fluid simulation of plasma characteristics in radio frequency ion thrusters

引用

Hangkong Dongli Xuebao/Journal of Aerospace Power 2025年第6期40卷

作者： Cui, Yunwei Ren, Junxue Zhang, Guangchuan Cao, Lehui Liu, Xuanlin Tang, Haibin School of Space and Earth Sciences Beihang University Beijing102206 China School of Astronautics Beihang University Beijing102206 China Key Laboratory of Spacecraft Design Optimization and Dynamic Simulation Technologies Ministry of Education School of Astronautics Beihang University Beijing102206 China Laboratory of Space Environment Monitoring and Information Processing Ministry of Industry and Information Technology School of Space and Earth Sciences Beihang University Beijing102206 China

The characteristics of the inductively coupled plasma (ICP) in the discharge chamber of a radio frequency ion thruster were studied as crucial factors affecting the thruster’s performance. A two-dimensional axisymmetric fluid model was developed for the radio frequency ion thruster discharge chamber. The simulation utilized a fifth-order weighted essentially non-oscillatory (WENO) scheme and the finite difference time domain (FDTD) method to solve the flow and electromagnetic field equations, respectively. Plasma characteristics inside the self-designed 3 cm diameter thruster discharge chamber were calculated. The simulation results indicated that the coupling of axial and radial induced magnetic fields, tangential induced electric fields, and tangential induced electric currents contributed mainly to maintaining ICP in the discharge chamber. In the heating mechanism of sustaining ICP, both random heating and Ohmic heating could play significant roles, and with an increase in radio frequency power, the proportion of random heating power to total heating power also increased. By increasing the radio frequency power, the beam current and propellant utilization efficiency of the radio frequency ion thruster rose, but the electrical efficiency decreased. Increasing the propellant flow rate led to an increase in thruster beam current but a gradual decrease in propellant utilization efficiency. © 2025 Beijing University of Aeronautics and Astronautics (BUAA). All rights reserved.

关键词： Ion propulsion

来源：评论

学校读者我要写书评

暂无评论

High-Resolution Particle Density Measurement for Argon Plasma Plume by Image Reconstruction and Collisional-Radiative Model

SSRN

引用

SSRN 2022年

作者： Han, Xing Wang, Yimeng Chen, Zhiyuan Wang, Yibai Wu, Jianjun Tang, Haibin Cao, Jinbin School of Space and Environment Beihang University Beijing100083 China School of Astronautics Beihang University Beijing100083 China Key Laboratory of Spacecraft Design Optimization and Dynamic Simulation Technologies of the Ministry of Education Beihang University Beijing100083 China Aircraft and Propulsion Laboratory Ningbo Institute of Technology Beihang University Ningbo315100 China College of Aerospace Science and Engineering National University of Defense Technology Changsha410073 China Laboratory of Space Environment monitoring and Information Processing Ministry of Industry and Information Technology Beijing100083 China

A measurement method of the high-resolution atom and ion density distributions based on the image reconstruction and collisional-radiative model is presented and could apply to the parameter measurement of the axisymmetric argon plasma plume. The projection integral signals of two-band ion spectral lines and one-band atom spectral line are acquired, and the spatial distribution of the light intensity signals are obtained by the image reconstruction technique. The collisional-radiative model includes the major atomic levels and singly ionized argon levels, taking into account electron-impact excitation and ionization, electron-impact deexcitation, three-body recombination processes to obtain the theoretical signal intensity in the wavelength bands as a function of electron temperature, electron density, and atom density. The plasma parameters are determined by the theoretical signal intensity and spatial light intensity with the three filters, and the common coefficient is calibrated by the known parameters of some positions. The method was applied to the plume region of an applied-field magnetoplasmadynamic thruster to verify the feasibility of this method in comparison with the electrostatic probe, and the plasma parameters with a spatial resolution of 0.81 mm/pixel were obtained finally. © 2022, The Authors. All rights reserved.

关键词： Argon

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：