检索结果-内蒙古大学图书馆

Efficient optimization method for variable-specific-impulse low-thrust trajectories with shutdown constraint

Science China(Technological Sciences) 2022年第3期65卷 581-594页

作者： JIA FeiDa QIAO Dong HAN HongWei LI XiangYu School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Key Laboratory of Autonomous Navigation and Control for Deep Space Exploration Ministry of Industry and Information TechnologyBeijing 100081China

This paper develops a sequential convex programming(SCP)-based method to solve the minimum-fuel variable-specific-impulse low-thrust transfer problem considering shutdown constraint,with emphasize on improving the computational *** variable parameter engine is more applicable for many low-thrust scenarios,therefore,both a continuously variable model and a ladder variable model are ***,the original problem is convexified by processing the constraint feasible domain,which is composed of the nonlinear dynamic equations and second-order equality constraint,into convex ***,the approximation is generated to close the optimal solution of the low-thrust problem by iteratively solving the convexified ***,the switching self-detection and adaptive node refinement methods are presented,which can improve the accuracy of the solution and accelerate the convergence during the approximation process and is especially necessary and effective in the scenarios with shutdown *** numerical simulations,the comparison with the homotopic approach shows that the proposed method only needs 4%computational time as that of the homotopic approach,and two variable-specificimpulse examples further demonstrate the effectiveness and efficiency of the proposed method.

关键词： low-thrust trajectory variable-specific-impulse shutdown constraint sequential convex programming switching self-detection and adaptive node refinement

来源：评论

学校读者我要写书评

暂无评论

A MEMS traveling-wave micromotor-based miniature gyrocompass

引用

Microsystems & Nanoengineering 2025年第1期11卷 335-346页

作者： Jinxuan Xie Tong Zhou Yu Chen Yi Zhou Bo Jiang Jing Zhang Zhenjun Wang Wentao Li Han Sun Xuyang Zhu Xiaoshi Li Tianyu Yang Yan Su School of Mechanical Engineering Nanjing University of Science and TechnologyNanjingChina Jiangsu Research Center for Intelligent Navigation and Control of Complex Motion NanjingChina Microsystem and Terahertz Research Center China Academy of Engineering PhysicsChengduChina Institute of Electronic Engineering China Academy of Engineering PhysicsMianyangChina

Traditional gyrocompasses,while capable of providing autonomous directional guidance and path correction,face limitations in widespread applications due to their large size,making them unsuitable for compact *** system(MEMS)gyrocompasses offer a promising alternative for ***,current MEMS gyrocompasses require the integration of motor rotation modulation technology to achieve high-precision north-finding,whereas conventional motors in previous research introduce large volume and residual magnetism,thus undermining their size ***,we innovatively propose a miniature MEMS gyrocompass based on a MEMS traveling-wave micromotor,featuring the first integration of a chip-scale rotational actuator and combined with a precise multi-position braking control system,enabling high accuracy and fast *** proposed gyrocompass made significant advancements,reducing its size to 50×42.5×24.5 mm^(3)and achieving an azimuth accuracy of 0.199°within 2 min,which is half the volume of the smallest existing similar devices while offering twice the *** improvements indicate that the proposed gyrocompass is suitable for applications in indoor industrial robotics,autonomous driving,and other related fields requiring precise directional guidance.

关键词： traveling wave micromotor gyrocompass motor rotation modulation technology miniaturization north finding conventional motors path correctionface autonomous directional guidance

来源：评论

学校读者我要写书评

暂无评论

A step to the decentralized real-time timekeeping network

引用

Chinese Physics B 2024年第1期33卷 183-191页

作者：王芳敏陈雨锋周建华蔺玉亭杨军王波王力军 State Key Laboratory of Precision Space-time Information Sensing Technology Department of Precision InstrumentTsinghua UniversityBeijing 100084China Key Laboratory of Photonic Control Technology Tsinghua UniversityBeijing 100084China Beijing Satellite Navigation Center Beijing 100094China Beijing Institute of Radio Metrology and Measurement Beijing 100854China

The composite time scale(CTS) provides an accurate and stable time-frequency reference for modern science and technology. Conventional CTS always features a centralized network topology, which means that the CTS is accompanied by a local master clock. This largely restricts the stability and reliability of the CTS. We simulate the restriction and analyze the influence of the master clock on the CTS. It proves that the CTS's long-term stability is also positively related to that of the master clock, until the region dominated by the frequency drift of the H-maser(averaging time longer than ~10~5s).Aiming at this restriction, a real-time clock network is utilized. Based on the network, a real-time CTS referenced by a stable remote master clock is achieved. The experiment comparing two real-time CTSs referenced by a local and a remote master clock respectively reveals that under open-loop steering, the stability of the CTS is improved by referencing to a remote and more stable master clock instead of a local and less stable master clock. In this way, with the help of the proposed scheme, the CTS can be referenced to the most stable master clock within the network in real time, no matter whether it is local or remote, making democratic polycentric timekeeping possible.

关键词： frequency synchronization network composite time scale frequency stability democratic timekeeping

来源：评论

学校读者我要写书评

暂无评论

Optimizing Epipolar Constraint Matching for Fisheye Cameras using Baseline Latitude-Longitude Technique 4

Optimizing Epipolar Constraint Matching for Fisheye Cameras ...

引用

4th International Computational Imaging Conference, CITA 2024

作者： You, Sibo Zhang, Yutong Zhang, Bozhi Ding, Yan Mo, Bo Song, Ping Beijing Institute of Technology Beijing100081 China China Electronics Technology Group Corporation 54th Research Institute Shijiazhuang050000 China North Navigation Control Technology Co. Ltd. Beijing100089 China

ISBN: (纸本)9781510688834

Visual Simultaneous Localization and Mapping (SLAM) systems often employ fisheye lenses due to their broad field of view, which enhances localization robustness. However, fisheye image distortion poses challenges for traditional epipolar constraint matching algorithms, affecting system accuracy and stability. In this paper, we propose a novel Baseline Latitude-Longitude technique to optimize epipolar search in fisheye images. Our approach constructs a coordinate system based on latitude and longitude, transforming the polar point search into a meridian search. Experimental results demonstrate that our method outperforms traditional matching algorithms, achieving higher recall and precision, thereby improving the robustness and accuracy of SLAM systems. This work has significant potential applications in autonomous drone navigation and other visual-based localization tasks. © 2025 SPIE.

关键词： Drones

来源：评论

学校读者我要写书评

暂无评论

Adaptive Prescribed-Time Neural control of Nonlinear Systems via Dynamic Surface Technique

IEEE Transactions on Artificial Intelligence

引用

IEEE Transactions on Artificial Intelligence 2024年第10期5卷 4948-4958页

作者： Wang, Ping Yu, Chengpu Lv, Maolong Zhao, Zilong Beijing Institute of Technology School of Automation Beijing100081 China Beijing Institute of Technology Chongqing Innovation Center Chongqing401120 China Air Force Engineering University College of Air Traffic Control and Navigation Xi'an710051 China Delft University of Technology Faculty of Electrical Engineering Mathematics and Computer Science Delft2628 CD Netherlands

The adaptive practical prescribed-time (PPT) neural control is studied for multiinput multioutput (MIMO) nonlinear systems with unknown nonlinear functions and unknown input gain matrices. Unlike existing PPT design schemes based on backstepping, this study proposes a novel PPT control framework using the dynamic surface control (DSC) approach. First, a novel nonlinear filter (NLF) with an adaptive parameter estimator and a piecewise function is constructed to effectively compensate for filter errors and facilitate prescribed-time convergence. Based on this, a unified DSC-based adaptive PPT control algorithm, augmented with a neural networks (NNs) approximator, is developed, where NNs are used to approximate unknown nonlinear system functions. This algorithm not only addresses the inherent computational complexity explosion associated with traditional backstepping methods but also reduces the constraints on filter design parameters compared to the DSC algorithm that relies on linear filters. The simulation showcases the effectiveness and superiority of the devised scheme by employing a two-degree-of-freedom robot manipulator. © 2024 IEEE.

关键词： Flexible manipulators

来源：评论

学校读者我要写书评

暂无评论

Measurement of SPT-140 Hall Thruster Swirl Torque during the Psyche Mission

Measurement of SPT-140 Hall Thruster Swirl Torque during the...

引用

AIAA Science and technology Forum and Exposition, AIAA SciTech Forum 2025

作者： Snyder, John Steven Nicholas, Austin K. Collins, Steven M. Ortega, Alejandro Lopez Electric Propulsion Group Jet Propulsion Laboratory California Institute of Technology PasadenaCA United States Navigation and Control Systems Engineer Jet Propulsion Laboratory California Institute of Technology PasadenaCA United States Guidance and Control Systems Section Jet Propulsion Laboratory California Institute of Technology PasadenaCA United States

ISBN: (数字)9781624107238

ISBN: (纸本)9781624107238

Hall-thruster swirl torque is small enough that it is difficult to measure in ground-based facilities, but large enough that its effects on interplanetary spacecraft can be significant and must be actively managed. NASA’s Psyche mission has provided the first opportunity to directly measure the swirl torque produced by a Hall thruster operating at powers greater than 1.5 kW. When the electric propulsion system is operating, the spacecraft attitude control methodology forces the net torque on the spacecraft to align with a pre-determined direction in the body frame, after which the thruster-induced swirl torque can be separated from the other torques acting on the spacecraft. The swirl torques produced by three of the four thrusters on the Psyche spacecraft were determined over the full operating discharge power range of 1.0 to 4.5 kW, and the maximum value of that torque was 0.86 mN-m at full power. It is shown that the SPT-140 swirl torque results can be scaled from full power to lower powers by the product of the discharge current and the magnet current, and evaluation of cruise thrusting data as the thruster is throttled down in power suggests that swirl torque is not changing significantly with time as a function of operating condition. Finally, calculations of swirl torque using updated numerical simulations are shown to agree reasonably well with the flight data, thus providing confidence in their use for other thrusters prior to flight. © 2025, American institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.

关键词： NASA

来源：评论

学校读者我要写书评

暂无评论

A non-probabilistic reliability topology optimization method based on aggregation function and matrix multiplication considering buckling response constraints

引用

Applied Mathematics and Mechanics(English Edition) 2024年第2期45卷 321-336页

作者： Lei WANG Yingge LIU Juxi HU Weimin CHEN Bing HAN Institute of Solid Mechanics School of Aeronautic Science and EngineeringBeihang UniversityBeijing 100191China Aircraft and Propulsion Laboratory Ningbo Institute of TechnologyBeihang UniversityNingbo 315100Zhejiang ProvinceChina State Key Laboratory of Navigation and Safety Technology Shanghai Ship and Shipping Research InstituteShanghai 200135China National Engineering Research Center of Ship&Shipping Control System Shanghai Ship and Shipping Research InstituteShanghai 200135China

A non-probabilistic reliability topology optimization method is proposed based on the aggregation function and matrix *** expression of the geometric stiffness matrix is derived,the finite element linear buckling analysis is conducted,and the sensitivity solution of the linear buckling factor is *** a specific problem in linear buckling topology optimization,a Heaviside projection function based on the exponential smooth growth is developed to eliminate the gray *** aggregation function method is used to consider the high-order eigenvalues,so as to obtain continuous sensitivity information and refined structural *** cyclic matrix programming,a fast topology optimization method that can be used to efficiently obtain the unit assembly and sensitivity solution is *** maximize the buckling load,under the constraint of the given buckling load,two types of topological optimization columns are *** variable density method is used to achieve the topology optimization solution along with the moving asymptote optimization *** vertex method and the matching point method are used to carry out an uncertainty propagation analysis,and the non-probability reliability topology optimization method considering buckling responses is developed based on the transformation of non-probability reliability indices based on the characteristic ***,the differences in the structural topology optimization under different reliability degrees are illustrated by examples.

关键词： buckling topology optimization aggregation function uncertainty propagation analysis non-probabilistic reliability

来源：评论

学校读者我要写书评

暂无评论

A Method for Calculating Solar Pressure of TDRS with a Movable IOLA 8th

A Method for Calculating Solar Pressure of TDRS with a Movab...

引用

8th International Conference on Signal and Information Processing, Network and Computers, ICSINC 2021

作者： Zhang, Yin Han, Dong Institute of Telecommunication and Navigation Satellites China Academy of Space Technology Beijing100094 China Beijing Institute of Control Engineering Beijing100190 China

ISBN: (纸本)9789811933868

In this paper, the solar pressure model of TDRS (tracking and data relay satellite) with a IOLA (inter-orbit link antenna) of large movable is studied, according to the actual satellite model, it is simplified and discretized;The geometric relationship among mesh antenna, satellite body and solar wing are accurately described by the projection calculation of the rotation of user satellite tracked by IOLA when the user satellite is tracked by antenna;By projecting the information of each part of the discrete satellite along the vector normal plane of the sun light, the shelter relation and the accurate solar pressure area can be obtained. Through the above method, the calculation of the solar pressure of the TDRS with a IOLA of movable mesh tracking the user satellite can be effectively solved. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Orbits

来源：评论

学校读者我要写书评

暂无评论

Design of Missile Roll Autopilot based on Linear Extended State Observer 34

Design of Missile Roll Autopilot based on Linear Extended St...

引用

第34届中国控制与决策会议

作者： Xu Xieyu Cui Xiaoxi Yu Wenbo Luo Penghao Gao Mi Norinco Group Institute of Navigation and Control Technology Beijing Aeronautic Technology Research Center Beijing JingHang Research Institute of Computing and Communication

ISBN: (纸本)9781665478977

With the expansion of missile envelope and the improvement of missile combat effect in recent years,the control of missile roll channel is faced with many kinds of unknown disturbances,such as oblique-blowing moment,additional torque at high angle-of-attack periodic interference of spin tail,severe noise and so on,which are very difficult to be modeled or analyzed *** traditional PID roll autopilot cannot keep the command tracking effectively under these *** on the ADRC idea,this paper designs a kind of LESO observer for missile roll channel without changing the original control parameters or structure,which can effectively estimate the disturbance and realize stable tracking of the roll angle command under all kinds of disturbance conditions.

关键词： LESO roll autopilot disturbance estimation and compensation ADRC

来源：评论

学校读者我要写书评

暂无评论

Study on Disturbing Moment Compensation for the Satellite with Large-Scale Rotating Antennas 8th

Study on Disturbing Moment Compensation for the Satellite wi...

引用

8th International Conference on Signal and Information Processing, Network and Computers, ICSINC 2021

作者： Fan, Wei Zhang, Yin Zeng, Haibo Beijing Institute of Control Engineering Beijing100190 China Science and Technology on Space Intelligent Control Laboratory Beijing100190 China Institute of Telecommunication and Navigation Satellites China Academy of Space Technology Beijing100094 China

ISBN: (纸本)9789811933868

In this paper, a method of interference feedforward compensation is proposed for the disturbance of satellites with large rotating antenna such as relay satellites with Large-scale Rotating Antennas. This method utilizes the angular momentum exchange device in advance to pre-compensate In order to reduce the disturbance of the satellite by calculating the coupling angular momentum changes of the satellite caused by the antenna motion at different positions. The simulation results show that the method can effectively reduce the interference of satellite when antennas do large-scale rotating which can make the attitude of the satellite more stable and the directional fluctuation of the platform smaller, which is conducive to the normal work of other satellite loads. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Satellites

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：