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Control of orientation for spacecraft formations in the vicinity of the Sun-Earth L2 libration point

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Science China(Physics,Mechanics & Astronomy) 2014年第9期57卷 1778-1787页

作者： QI Rui XU ShiJie CHEN Tong school of Aerospace Engineering beijing institute of technology Department of Guidance Navigation and Control School of Astronautics Beihang University

Formation flying in the vicinity of the libration point is an important concept for space exploration and demands reliable and accurate techniques for the control of a *** the basis of previous works,this paper addresses the problem of relative orientation control of spacecraft formation flying utilizing the framework of the circular restricted three-body problem(CR3BP)with the Sun and Earth as the primary gravitational *** specific tasks are accomplished in this ***,the tangent targeting method(TTM),an efficient two-level differential correction algorithm,is exploited to control the Chief/Deputy architecture to maintain a prespecified *** time spent within the orientation error corridor between successive maneuvers is maximized while the relative separation between the vehicles is held constant at each target *** second task is to further optimize the maneuver intervals by dropping the constraint imposed on the relative vehicle *** investigation indicates that the number of maneuvers can be significantly reduced and the length of time between successive maneuvers can be greatly increased by utilizing the TTM.

关键词： formation flight three body problem libration point tangent targeting method

Free-walking:Pedestrian inertial navigation based on dual foot-mounted IMU

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Defence Technology（防务技术） 2024年第3期33卷 573-587页

作者： Qu Wang Meixia Fu Jianquan Wang Lei Sun Rong Huang Xianda Li Zhuqing Jiang Yan Huang Changhui Jiang school of Automation Science and Electrical Engineering University of Science and Technology BeijingBeijing100083China Shunde Innovation school University of Science and Technology BeijingFo Shan528399China Research Institute of China Unicom Beijing100190China school of Artificial Intelligence Beijing University of Posts and TelecommunicationsBeijing100876China Department of Automation Tsinghua University Beijing100084China GEOLOC Laboratory Universite Gustave EiffelParis77454France

The inertial navigation system(INS),which is frequently used in emergency rescue operations and other situations,has the benefits of not relying on infrastructure,high positioning frequency,and strong real-time ***,the intricate and unpredictable pedestrian motion patterns lead the INS localization error to significantly diverge with *** paper aims to enhance the accuracy of zero-velocity interval(ZVI)detection and reduce the heading and altitude drift of foot-mounted INS via deep learning and equation constraint of dual *** at the observational noise problem of low-cost inertial sensors,we utilize a denoising autoencoder to automatically eliminate the inherent *** at the problem that inaccurate detection of the ZVI detection results in obvious displacement error,we propose a sample-level ZVI detection algorithm based on the U-Net neural network,which effectively solves the problem of mislabeling caused by sliding *** at the problem that Zero-Velocity Update(ZUPT)cannot suppress heading and altitude error,we propose a bipedal INS method based on the equation constraint and ellipsoid constraint,which uses foot-to-foot distance as a new observation to correct heading and altitude *** conduct extensive and well-designed experiments to evaluate the performance of the proposed *** experimental results indicate that the position error of our proposed method did not exceed 0.83% of the total traveled distance.

关键词： Indoor positioning Inertial navigation system(INS) Zero-velocity update(ZUPT) Internet of things(IoTs) Location-based service(LBS)

Predictor-based neural dynamic surface control for distributed formation tracking of multiple marine surface vehicles with improved transient performance

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Science China(Information Sciences) 2016年第9期59卷 208-226页

作者： Zhouhua PENG Dan WANG Tieshan LI school of Marine Engineering Dalian Maritime University Control Science and Engineering Dalian University of Technology school of navigation Dalian Maritime University

In this paper, we investigate the distributed formation tracking problem of multiple marine surface vehicles with model uncertainty and time-varying ocean disturbances induced by wind, waves, and ocean currents. The objective is to achieve a collective tracking with a time-varying trajectory, which can only be accessed by a fraction of follower vehicles. A novel predictor-based neural dynamic surface control design approach is proposed to develop the distributed adaptive formation controllers. We use prediction errors, rather than tracking errors, to construct the neural adaptive laws, which enable the fast identification of the vehicle dynamics without incurring high-frequency oscillations in control signals. We establish the stability properties of the closed-loop network via Lyapunov analysis, and quantify the transient performance by deriving the truncated L2 norms of the derivatives of neural weights, which we demonstrate to be smaller than the classical neural dynamic surface control design approach. We also extend the above result to the distributed formation tracking using the relative position information of vehicles, and the advantage is that the velocity information of neighbors and leader are required. Finally, we give the comparative studies to illustrate the performance improvement of the proposed method.

关键词： dynamic surface control distributed formation tracking predictor marine surface vehicles neural networks

Simulation Research on Operation of Union Purchase System in navigation Simulator

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Journal of Shanghai Jiaotong university(Science) 2020年第5期25卷 606-614页

作者： FAN hang YANG Shenhua SUO Yongfeng ZHENG Minjie school of navigation College Jimei UniversityXiamen 361021FujianChina

navigation is the only way to develop and utilize marine resources,while the promotion of seafarers1 quality is the basic force of navigation,so navigation simulator plays an important role in modern navigation *** simulation research on the operation of the union purchase is important to improve the special operation training of the actual cargo handling of the union *** the basis of the Cartesian coordinate system transformation algorithm,the algorithm model of the union purchase operation is *** the basis of three-dimensional(3D)rendering engine technology of open scene graph(OSG),the algorithm model of finding the space coordinates of the cargo point is *** model of catenary equation is used to optimize the scene appearance of the cargo *** combination of QT channel signal mechanism and OSG,the simulation interaction of the union purchase operating system is *** acquiring the 3D coordinate values of each point,we fit the trajectories of each point in the operation and compare the *** results show that the model has high interactivity and small *** comparison of the states of the cargo wire before and after optimization shows that the optimized wire is more realistic and the high fidelity meets the needs of operational training and simulation systems.

关键词： navigation simulator union purchase coordinate system transformation open scene graph(OSG) catenary equation

Metamaterial terahertz device with temperature regulation function that can achieve perfect absorption and complete reflection conversion of ultrawideband

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Communications in Theoretical Physics 2024年第7期76卷 123-133页

作者： Hao Sun Zao Yi Can Ma Shubo Cheng Bin Tang Qingdong Zeng Sohail Ahmad school of Mathematics and Science Joint Laboratory for Extreme Conditions Matter PropertiesState Key Laboratory of Environment-Friendly Energy MaterialsTianfu Institute of Research and InnovationSouthwest University of Science and TechnologyMianyang 621010China Department of Oncology Sichuan Science City HospitalMianyangSichuan Province621000China school of Chemistry and Chemical Engineering Jishou UniversityJishou 416000China school of Physics and Optoelectronic Engineering Yangtze UniversityJingzhouHubei 434023China school of Microelectronics and Control Engineering Changzhou UniversityChangzhou 213164China school of Physics and Electronic Information Engineering Hubei Engineering UniversityXiaogan 432000China Institute of Physics Bahauddin Zakariya UniversityMultan 66000Pakistan

The field of terahertz devices is important in terahertz ***,most of the current devices have limited functionality and poor *** improve device performance and achieve multifunctionality,we designed a terahertz device based on a combination of VO_(2)and *** device can be tuned using the phase-transition characteristics of VO_(2),which is included in the triple-layer structure of the device,along with SiO_(2)and *** terahertz device exhibits various advantageous features,including broadband coverage,high absorption capability,dynamic tunability,simple structural design,polarization insensitivity,and incidentangle *** simulation results showed that by controlling the temperature,the terahertz device achieved a thermal modulation range of spectral absorption from 0 to *** 313 K,the device exhibited complete reflection of terahertz *** the temperature increased,the absorption rate also *** the temperature reached 353 K,the device absorption rate exceeded 97.7%in the range of 5-8.55 *** study used the effective medium theory to elucidate the correlation between conductivity and temperature during the phase transition of VO_(2).Simultaneously,the variation in device performance was further elucidated by analyzing and depicting the intensity distribution of the electric field on the device surface at different ***,the impact of various structural parameters on device performance was examined,offering valuable insights and suggestions for selecting suitable parameter values in real-world *** characteristics render the device highly promising for applications in stealth technology,energy harvesting,modulation,and other related fields,thus showcasing its significant potential.

关键词： terahertz perfect absorption complete reflection temperature regulation ultrawideband smart device

navigation Finsler metrics on a gradient Ricci soliton

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Applied Mathematics(A Journal of Chinese Universities) 2024年第2期39卷 266-275页

作者： LI Ying MO Xiao-huan WANG Xiao-yang Department of Applied Mathematics Zhejiang University of TechnologyHangzhou 310023China Key Laboratory of Pure and Applied Mathematics School of Mathematical SciencesPeking UniversityBeijing 100871China school of Mathematics and Statistics Beijing Institute of TechnologyBeijing 100081China

In this paper,we study a class of Finsler metrics defined by a vector field on a gradient Ricci *** obtain a necessary and sufficient condition for these Finsler metrics on a compact gradient Ricci soliton to be of isotropic S-curvature by establishing a new integral *** we determine the Ricci curvature of navigation Finsler metrics of isotropic S-curvature on a gradient Ricci soliton generalizing result only known in the case when such soliton is of Einstein *** its application,we obtain the Ricci curvature of all navigation Finsler metrics of isotropic S-curvature on Gaussian shrinking soliton.

关键词： gradient Ricci soliton navigation Finsler metric isotropic S-curvature Ricci curvature Gaussian shrinking soliton

Deformation and Locomotion of Untethered Small-Scale Magnetic Soft Robotic Turtle with Programmable Magnetization

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Journal of Bionic Engineering 2024年第2期21卷 754-763页

作者： Lin Xu Liu Yang Tao Li Xingbang Zhang Jianning Ding school of Mechanical Engineering Jiangsu UniversityZhenjiang212013China The Key Laboratory of Bionic Engineering(Ministry of Education) Jilin UniversityChangchun130012China Shanghai Tianchun Technology Co. LtdShanghai201802China school of Mechanical Engineering Yangzhou UniversityYangzhou225009China

Inspired by the way sea turtles rely on the Earth’s magnetic field for navigation and locomotion,a novel magnetic soft robotic turtle with programmable magnetization has been developed and investigated to achieve biomimetic locomotion patterns such as straight-line swimming and turning *** soft robotic turtle(12.50 mm in length and 0.24 g in weight)is integrated with an Ecoflex-based torso and four magnetically programmed acrylic elastomer VHB-based limbs containing samarium-iron–nitrogen particles,and was able to carry a load more than twice its own *** to the limb locomotion characteristics of sea turtles,the magnetic torque causes the four limbs to mimic sinusoidal bending deformation under the influence of an external magnetic field,so that the turtle swims continuously ***,when the bending deformation magnitudes of its left and right limbs differ,the soft robotic turtle switches from straight-line to turning swimming at 6.334 rad/***,the tracking swimming activities of the soft robotic turtle along specific planned paths,such as square-shaped,S-shaped,and double U-shaped maze,is anticipated to be utilized for special detection and targeted drug delivery,among other applications owing to its superior remote directional control ability.

关键词： Magnetic soft robotic turtle Programmable magnetization Untethered soft robotics Bending deformation

Analysis of Commonly and Specifically Dysregulated Pathways in Three Women Cancers

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Chinese Journal of Electronics 2018年第5期27卷 1043-1049页

作者： LIU Xiyang AN Yingying YU Baoguo QIN Guimin school of Software Xidian University school of Computer Science and Technology Xidian University State Key Laboratory of Satellite navigation System and Equipment Technology

Breast, ovarian and endometrial cancer are three most prevalent gynaecological malignancies. Identifying their common and specific biomarkers is significant for cancer prediction and therapy in females. We propose a method to identify dysregulated pathways in cancer through scoring pathways based on the molecular interaction data and genomic data. Commonly and specifically dysregulated pathways are analyzed across the above three female cancers, which have not been studied as a whole to the best of our knowledge. Our results demonstrate that all the three cancers have close relationships with Type II diabetes and cell cycle-related biology processes. Breast cancer is specifically related to immune system while ovarian cancer and endometrial cancer are associated with blood vascular-related systems such as renin-angiotensin system and coagulation system. In addition, dysregulated pathways are used to predict potential driver genes effectively according to their topological structure and biological information.

关键词： Dysregulated pathway Female cancers Driver gene

Anti-Spoofing:Integrated Information Authentication of BeiDou-ⅡCivil navigation Message

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China Communications 2024年第9期21卷 242-261页

作者： Wu Zhijun Liang Cheng Zhang Yun Liu Rusen Yue Meng school of Safety Science and Engineering Civil Aviation University of ChinaTianjin 300300China school of Electronic Information and Automation Civil Aviation University of ChinaTianjin 300300China Dalian Air Traffic Management Station of Civil Aviation of China Dalian 116000China

The BeiDou-Ⅱcivil navigation message(BDⅡ-CNAV)is transmitted in an open environment and no information integrity protection measures are ***,the BDⅡ-CNAV faces the threat of spoofing attacks,which can lead to wrong location reports and time *** order to deal with this threat,we proposed a scheme of anti-spoofing for BDⅡ-CNAV based on integrated information *** scheme generates two type authentication information,one is authentication code information(ACI),which is applied to confirm the authenticity and reliability of satellite time information,and the other is signature information,which is used to authenticate the integrity of satellite location information and other *** authentication information is designed to embed into the reserved bits in BDⅡ-CNAV without changing the frame *** order to avoid authentication failure caused by public key error or key error,the key or public key prompt information(KPKPI)are designed to remind the receiver to update both keys in *** results indicate that the scheme can successfully detect spoofing attacks,and the authentication delay is less than 1%of the transmission delay,which meets the requirements of BDⅡ-CNAV information authentication.

关键词： anti-spoofing authentication BeiDou-II civil navigation message(BDII-CNAV) signature spoofing attack