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Sliding-Mode-Based Attitude Tracking Control of Spacecraft Under Reaction Wheel Uncertainties

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IEEE/CAA Journal of Automatica Sinica 2023年第6期10卷 1475-1487页

作者： Wei Chen Qinglei Hu the School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China. The beihang hangzhou innovation institute yuhang Hangzhou 310023China

The attitude tracking operations of an on-orbit spacecraft with degraded performance exhibited by potential actuator uncertainties(including failures and misalignments) can be extraordinarily challenging. Thus, the control law development for the attitude tracking task of spacecraft subject to actuator(namely reaction wheel) uncertainties is addressed in this paper. More specially, the attitude dynamics model of the spacecraft is firstly established under actuator failures and misalignment(without a small angle approximation operation). Then, a new non-singular sliding manifold with fixed time convergence and anti-unwinding properties is proposed, and an adaptive sliding mode control(SMC) strategy is introduced to handle actuator uncertainties, model uncertainties and external disturbances simultaneously. Among this, an explicit misalignment angles range that could be treated herein is offered. Lyapunov-based stability analyses are employed to verify that the reaching phase of the sliding manifold is completed in finite time, and the attitude tracking errors are ensured to converge to a small region of the closest equilibrium point in fixed time once the sliding manifold enters the reaching phase. Finally, the beneficial features of the designed controller are manifested via detailed numerical simulation tests.

关键词： Actuator failures actuator misalignment angles finite time sliding mode control(SMC) spacecraft attitude tracking

A Secure Mutual Authentication Protocol Based on Visual Cryptography Technique for IoT-Cloud

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Chinese Journal of Electronics 2024年第1期33卷 43-57页

作者： Brou Bernard Ehui Chen CHEN Shirui WANG Hua GUO Jianwei LIU School of Cyber Sciences and Technology Beihang University State Key Laboratory of Software Development Environment Beihang University Sino-French Engineering School Beihang University beihang hangzhou innovation institute yuhang

Because of the increasing number of threats in the IoT cloud, an advanced security mechanism is needed to guard data against hacking or attacks. A user authentication mechanism is also required to authenticate the user accessing the cloud services. The conventional cryptographic algorithms used to provide security mechanisms in cloud networks are often vulnerable to various cyber-attacks and inefficient against new attacks. Therefore,developing new solutions based on different mechanisms from traditional cryptography methods is required to protect data and users’ privacy from attacks. Different from the conventional cryptography method, we suggest a secure mutual authentication protocol based on the visual cryptography technique in this paper. We use visual cryptography to encrypt and decrypt the secret images. The mutual authentication is based on two secret images and *** user requests the ticket from the authentication server(AS) to obtain the permission for accessing the cloud services. Three shared secret keys are used for encrypting and decrypting the authentication process. We analyze the protocol using the Barrows-Abadi-Needham(BAN)-logic method and the results show that the protocol is robust and can protect the user against various attacks. Also, it can provide a secure mutual authentication mechanism.

关键词： Visualization Cloud computing Data privacy Protocols Biometrics (access control) Authentication Resists

Neural network-based fault diagnosis for spacecraft with single-gimbal control moment gyros

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Chinese Journal of Aeronautics 2022年第7期35卷 261-273页

作者： Yuandong LI Qinglei HU Xiaodong SHAO School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100083China beihang hangzhou innovation institute yuhang Hangzhou 310023China School of Aeronautic Science and Engineering Beihang UniversityBeijing 100083China

This paper proposes a neural network-based fault diagnosis scheme to address the problem of fault isolation and estimation for the Single-Gimbal Control Moment Gyroscopes(SGCMGs)of spacecraft in a periodic *** this end,a disturbance observer based on neural network is developed for active anti-disturbance,so as to improve the accuracy of fault *** periodic disturbance on orbit can be decoupled with fault by resorting to the fitting and memory ability of neural ***,the fault diagnosis scheme is established based on the idea of information *** data of spacecraft attitude and gimbals position are combined to implement fault isolation and estimation based on adaptive estimator and neural ***,an adaptive sliding mode controller incorporating the disturbance and fault estimation results is designed to achieve active fault-tolerant *** addition,the paper gives the proof of the stability of the proposed schemes,and the simulation results show that the proposed scheme achieves better diagnosis and control results than compared algorithm.

关键词： Control moment gyro Fault diagnosis Fault-tolerant control Neural networks Spacecraft attitude control

Dynamic range and linearity improvement for zero-field single-beam atomic magnetometer

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Chinese Physics B 2022年第11期31卷 284-290页

作者： Kai-Feng Yin Ji-Xi Lu Fei Lu Bo Li Bin-Quan Zhou Mao Ye School of Instrumentation Science and Optoelectronics Engineering Beihang UniversityBeijing 100191China Research institute for Frontier Science Beihang UniversityBeijing 100191China beihang hangzhou innovation institute yuhang Xixi Octagon CiyHangzhou 310023China

Zero-field single-beam atomic magnetometers with transverse parametric modulation for ultra-weak magnetic field detection have attracted widespread attention *** this study,we present a comprehensive response model and propose a modification method of conventional first harmonic response by introducing the second harmonic *** proposed modification method gives improvement in dynamic range and reduction of linearity ***,our modification method shows suppression of response instability caused by optical intensity and frequency *** atomic magnetometer with single-beam configuration is built to compare the performance between our proposed method and the conventional *** results indicate that our method’s magnetic field response signal achieves a 5-fold expansion of dynamic range from 2 nT to 10 nT,with the linearity error decreased from 5%to 1%.Under the fluctuations of 5%for optical intensity and±15 GHz detuning of frequency,the proposed modification method maintains intensityrelated instability less than 1%and frequency-related instability less than 8%while the conventional method suffers 15%and 38%,*** method is promising for future high-sensitive and long-term stable optically pumped atomic sensors.

关键词： atomic magnetometer dynamic range linearity error response signal stability

Calibration of S-duct Swirl Distortion Based on Vortex Identification Methods

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Journal of Thermal Science 2022年第1期31卷 35-46页

作者： SUN Dakun LI Zhenyu DONG Xu SUN Xiaofeng School of Energy and Power Engineering Beihang UniversityBeijing 100191China Research institute of Aero-engine Beihang UniversityBeijing 100191China beihang hangzhou innovation institute yuhang Hangzhou 310023China Shen Yuan Honors College Beihang UniversityBeijing 100191China

The S-shape inlet has been widely used in advanced military aircraft due to their advantage of reducing radar ***,the curvature of the inlet usually causes different kinds of intake distortion at the aerodynamic interface plane(AIP).Among them,the swirl distortion has been seriously concerned because of its great impact on the performance and stability of *** is still no universal criterion for assessing the stability of compressors in the condition of strong swirl *** an approach of assessing the swirl intensity and pattern,vortex identification method may be used as an auxiliary method for stability *** this paper,numerical and experimental investigations on different S-ducts were carried *** axial vorticity component and g criterion were used to analyze the quantitative correlation between geometry and swirl *** was found that there is a relatively strong correlation between the geometry,the axial vorticity component and the Q *** present investigation may provide a quick reconstruction method to model the effect of S-ducts for compressor stability prediction.

关键词： S-inlet swirl distortion vortex identification

Improving the tensile properties of extruded Mg–Ga alloy by ageing treatment

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Progress in Natural Science:Materials International 2022年第6期32卷 724-731页

作者： Donglei He Hao Gong Ziyue Zhang Yang Zheng Hu Zhang Yan Li School of Materials Science and Engineering Beihang University Key Laboratory of Aerospace Advanced Materials and Performance (beihang University) Ministry of Education School of Aeronautics and Astronautics Tiangong University beihang hangzhou innovation institute yuhang Beihang University Beijing Advanced innovation Centre for Biomedical Engineering Beihang University

A hot-extruded Mg-5Ga alloy was subjected to ageing treatment at 150℃,190℃ and 230℃.The microstructures and mechanical properties of the extruded and aged alloy were examined in this *** examinations suggested that particle-shaped and rod-shaped Mg5Ga2were precipitated in the alloy after peak ageing *** extruded alloy showed the yield strength,ultimate tensile strength and elongation to fracture of 157.6 MPa,248.6 MPa and 17.5%,*** peak ageing,the yield strength and ultimate tensile strength can be enhanced by as much as 15.7% and 8.6% reaching 182.3 MPa and 270 MPa,*** improvement of the tensile strengths is mainly attributed to the enhanced precipitation strengthening by newly formed fine *** ductility of the alloy was slightly increased by peak ageing at low temperatures(150℃ and 190 ℃),but remarkably decreased by peak ageing at high temperature(230℃) due to the formation of coarsened Mg5Ga2particles which easily initiated the cracks during tensile deformation.

关键词： Mg-Ga alloy Microstructure Mechanical property Ageing treatment

Effect of wire mesh casing treatment on axial compressor performance and stability

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Chinese Journal of Aeronautics 2024年第3期37卷 60-76页

作者： Ming ZHANG Jiaming ZHANG Jiahao HU Xu DONG Dakun SUN Xiaofeng SUN School of Energy and Power Engineering Beihang UniversityBeijing 100191China beihang hangzhou innovation institute yuhang Hangzhou 310023China National Key Laboratory of Science and Technology on Aero-Engine Aero-Thermodynamics Beihang UniversityBeijing 100191China

In this paper,a kind of Wire Mesh Casing Treatment(WMCT)is proposed to improve the stable operating range of the *** contrast to the traditional circumferential groove,as for WMCT,a layer of wire mesh is laid on the surface of the circumferential *** studies were conducted on the low-speed axial flow compressor,including the groove width,axial location,and mesh *** optimum axial location for WMCT is related to its groove width.A higher wire mesh count results in a smaller compressor stall margin *** simulations were carried out to study the effect of WMCT on the flow structure of the *** wire mesh in the WMCT has a certain flow resistance,which restricts the flow into and out of the *** to the WMCT,the flow parameter in the tip region of the rotor is less sensitive to changes in the operating conditions of the *** WMCT causes the rotor tip blade loading to shift backward,inhibiting the formation of spill forward of the leakage flow,and thus improving the stability of the *** flow resistance on the groove surface is a new degree-of-freedom for the casing treatment designer.

关键词： Axial compressor Wire mesh casing treatment Tip clearance flow Stall margin Blade loading

Light field super-resolution using complementary-view feature attention

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Computational Visual Media 2023年第4期9卷 843-858页

作者： Wei Zhang Wei Ke Da Yang Hao Sheng Zhang Xiong Faculty of Applied Sciences Macao Polytechnic UniversityMacao SAR 999078China State Key Laboratory of Software Development Environment School of Computer Science and EngineeringBeihang UniversityBeijing 100191Chinaand Beihang Hangzhou Innovation Institute YuhangXixi Octagon CityYuhang DistrictHangzhou 310023China

Light field(LF)cameras record multiple perspectives by a sparse sampling of real scenes,and these perspectives provide complementary *** information is beneficial to LF super-resolution(LFSR).Compared with traditional single-image super-resolution,LF can exploit parallax structure and perspective correlation among different LF ***,the performance of existing methods are limited as they fail to deeply explore the complementary information across LF *** this paper,we propose a novel network,called the light field complementary-view feature attention network(LF-CFANet),to improve LFSR by dynamically learning the complementary information in LF ***,we design a residual complementary-view spatial and channel attention module(RCSCAM)to effectively interact with complementary information between complementary ***,RCSCAM captures the relationships between different channels,and it is able to generate informative features for reconstructing LF images while ignoring redundant ***,a maximum-difference information supplementary branch(MDISB)is used to supplement information from the maximum-difference angular positions based on the geometric structure of LF *** branch also can guide the process of *** results on both synthetic and real-world datasets demonstrate the superiority of our *** proposed LF-CFANet has a more advanced reconstruction performance that displays faithful details with higher SR accuracy than state-of-the-art methods.

关键词： light field(LF) super-resolution(SR) attention

EScope:Effective Event Validation for IoT Systems Based on State Correlation

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Big Data Mining and Analytics 2023年第2期6卷 218-233页

作者： Jian Mao Xiaohe Xu Qixiao Lin Liran Ma Jianwei Liu School of Cyber Science and Technology Beihang UniversityBeijing 100191China beihang hangzhou innovation institute yuhang Hangzhou 310023China Department of Computer Science Texas Christian UniversityFort WorthTX 76129USA

Typical Internet of Things(IoT)systems are event-driven platforms,in which smart sensing devices sense or subscribe to events(device state changes),and react according to the preconfigured trigger-action logic,as known as,automation rules.“Events”are essential elements to perform automatic control in an IoT ***,events are not always *** fake event notifications injected by attackers(called event spoofing attack)can trigger sensitive actions through automation rules without involving authorized *** solutions verify events via“event fingerprints”extracted by surrounding ***,if a system has homogeneous sensors that have strong correlations among them,traditional threshold-based methods may cause information redundancy and noise amplification,consequently,decreasing the checking *** at this,in this paper,we propose“EScope”,an effective event validation approach to check the authenticity of system events based on device state *** selects informative and representative sensors using an Neural-Network-based(NN-based)sensor selection component and extracts a verification sensor set for event *** evaluate our approach using an existing dataset provided by *** experiment results demonstrate that EScope achieves an average 67%sensor amount reduction on 22 events compared with the existing work,and increases the event spoofing detection accuracy.

关键词： Internet of Things(IoT) event spoofing event fingerprint correlation analysis