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    Real-time dense small object detection algorithm for UAV based on improved YOLOv5
    ACTA AERONAUTICAET ASTRONAUTICA SINICA    DOI: 10.7527/S1000-6893.2022.27106
    Accepted: 09 May 2022

    Technical innovations of the Tianwen-1 Mission
    ZHANG Rongqiao, GENG Yan, SUN Zezhou, LI Dong, ZHONG Wenan, LI Haitao, CUI Xiaofeng, LIU Jianjun
    ACTA AERONAUTICAET ASTRONAUTICA SINICA    2022, 43 (3): 626689-626689.   DOI: 10.7527/S1000-6893.2021.26689
    Abstract1078)   HTML76)    PDF(pc) (2192KB)(683)       Save
    Tianwen-1 is the first mission in the world to achieve the three goals of Mars orbiting, landing and roving in one mission, and has made some key-technology breakthroughs. The mission objectives and flight progress are introduced, and eight kinds of innovation achievements and the main technical breakthroughs are comprehensively summarized in this paper. Specifically, the key technologies include the overall design of Mars orbiting, landing and roving objectives strongly coupled, multi-trajectory launch of Earth escape orbit, interplanetary flight and Mars capture, Mars enter, descent and landing, solutions adaptive to Martian harsh environment, 400-million-kilometer communication, advanced payloads of remote sensing and patrol detection, and Mars environmental modeling and ground validation. The complete success of the mission has made China become one of the advanced countries in the field of deep space exploration.
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    Development status, challenges and trends of strength technology for hypersonic vehicles
    SUN Cong
    ACTA AERONAUTICAET ASTRONAUTICA SINICA    2022, 43 (6): 527590-527590.   DOI: 10.7527/S1000-6893.2022.27590
    Abstract1030)   HTML286)    PDF(pc) (26942KB)(897)       Save
    As a type of hi-tech weapon, hypersonic vehicle plays an important strategic role in national security and benefits. It has now become a research hotspot in the field of aerospace, and the competition is becoming increasingly fierce all over the world. Advanced material and structure design is a basic key technology to support the development of hypersonic vehicle. The strength of materials and structures in extremely severe service environments is still a key issue restricting the development of this type of aircraft. This paper reviews the structure strength problems and evolution characteristics in the field of hypersonic vehicles in the past few decades. Combined with the current vehicle model development demand and technology development trend, this paper analyzes the current situation and shortcomings of structure strength technology in supporting the development of hypersonic vehicles and discusses the new requirements, new characteristics and new methods of strength problems in this field in the future. Finally, the future development direction in the field of hypersonic vehicle structure strength is proposed after summarization.
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    Review of distributed hybrid electric propulsion aircraft technology
    ZHU Bingjie, YANG Xixiang, ZONG Jian'an, DENG Xiaolong
    ACTA AERONAUTICAET ASTRONAUTICA SINICA    2022, 43 (7): 25556-025556.   DOI: 10.7527/S1000-6893.2021.25556
    Abstract998)   HTML22)    PDF(pc) (14513KB)(567)       Save
    Distributed hybrid electric propulsion system has great potential and advantage in development of general electric aviation. By the optimization of secondary power system, hybrid electric technology can not only heighten the utilization efficiency of energy, but also satisfied the distributed arrangement of power system for higher propulsive efficiency. The paper firstly summarized the current major types of electric aircraft, reviewed the history background of distributed electric propulsion aircraft. Then, the research status of distributed hybrid electric propulsion aircraft technology is summarized, this part mainly discussed the distributed layout technology of propulsion system, type-selection design of hybrid electric propulsion system, modeling and energy management of hybrid electric propulsion system, and so on. The key technologies of distributed hybrid electric propulsion at home and abroad are discussed fully. Eventually, combined with the research of the team, the difficult point problems and solutions of distributed hybrid electric propulsion aircraft are discussed in detail, including dynamic management strategy of energy based on complex system optimization control, optimal energy distribution prediction model driven by historical big data, and principle prototype designing of distributed hybrid electric propulsion system. The main content of this paper clarify the design thoughts and analysis method for distributed hybrid electric propulsion system and energy arrangement, which can provide references for the research of electric propulsion aircraft technology.
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    Effects of belly flap on take-off and landing characteristics of a flying-wing vehicle
    CHEN Xian, CHEN Cheng, HUANG Jiangtao, CHEN Qisheng, YU Longzhou, ZHONG Shidong
    ACTA AERONAUTICAET ASTRONAUTICA SINICA    2022, 43 (3): 125028-125028.   DOI: 10.7527/S1000-6893.2021.25028
    Abstract776)   HTML31)    PDF(pc) (13700KB)(468)       Save
    Taking a flying wing configuration model as the initial shape of flying wing configuration aircraft, the location and the deflection angle of belly-flaps in the take-off and landing process are studied by the method of numerical simulation, and the influence law of belly-flap deflection on elevator rudder effect and ground effect is obtained.The results show that when the belly-flap is located at 40% mean aerodynamic chord behind the center of gravity, a high lift enhancement efficiency can be maintained at high angles of attack, and there is a small change in the pitching moment.As the deflection angle of the belly-flap increases, the lift and the drag show a quasi linear growth, while the change of the pitching moment is small and can be trimmed by about 1° deflection of the elevator.When the belly-flap is deflected, the rudder efficiency of the elevator decreases by about 6%, and the increment of lift caused by ground effect increases, while the longitudinal static stability is decreased.
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    Research status and prospect of fault diagnosis for gas turbine aeroengine
    LIN Jing, ZHANG Boyao, ZHANG Dayi, CHEN Min
    ACTA AERONAUTICAET ASTRONAUTICA SINICA    2022, 43 (8): 626565-626565.   DOI: 10.7527/S1000-6893.2021.26565
    Abstract748)   HTML78)    PDF(pc) (5160KB)(515)       Save
    Gas turbine engine is a comprehensive embodiment of the level of national science, technology and industry. Fault diagnosis is an important guarantee for its safe and reliable operation and an essential indicator of engine advancement. However, due to the complicated structure, highly integrated system, harsh service environment, variable mission profiles, the constraints of limited online testing conditions, and the poor supportability of diagnostic information acquisition, the fault diagnosis for aeroengine faces multiple challenges. In this paper, the research status in China and abroad is firstly reviewed and analyzed from three aspects: gas path analysis and performance evaluation, mechanical fault diagnosis and information fusion. Then, the exciting key problems and challenges in the current research are pointed out. Finally, the future development trends are discussed.
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    Progress in hypersonic boundary layer transition delay control
    LIU Qiang, TU Guohua, LUO Zhenbing, CHEN Jianqiang, ZHAO Rui, YUAN Xianxu
    ACTA AERONAUTICAET ASTRONAUTICA SINICA    2022, 43 (7): 25357-025357.   DOI: 10.7527/S1000-6893.2021.25357
    Abstract737)   HTML33)    PDF(pc) (5986KB)(304)       Save
    Due to the large difference between laminar flow and turbulent flow in wall friction and wall heat flow, the transition control of the hypersonic boundary layer is of vital importance to the aerodynamic performance and thermal protection system of vehicles. This paper first summarizes the main instability mechanisms of hypersonic boundary layers, followed by a review of the latest progress in the hypersonic boundary layer transition delay control technology from two aspects, namely, passive control and active control technologies. Passive control methods such as roughness elements, wavy wall, and porous coating are then introduced in detail, the active control measures such as wall heating/cooling and heavy gas injection described, the physical mechanism behind the control analyzed, and the advantages and disadvantages of various control technologies discussed. Finally, suggestions and prospects for further research on transition delay control are presented.
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    Stereo visual-inertial SLAM algorithm based on merge of point and line features
    ZHAO Liangyu, JIN Rui, ZHU Yeqing, GAO Fengjie
    ACTA AERONAUTICAET ASTRONAUTICA SINICA    2022, 43 (3): 325117-325117.   DOI: 10.7527/S1000-6893.2021.25117
    Abstract727)   HTML5)    PDF(pc) (11028KB)(222)       Save
    In indoor weakly textured environment, it is difficult for the SLAM algorithm based on point features to track sufficient effective point features, which leads to low accuracy and robustness, and even causes the system to fail completely. For this problem, a stereo visual SLAM algorithm is proposed based on point and line features and the Inertial Measurement Unit (IMU). The data association accuracy is improved by using the complementation of point and line features, and meanwhile the IMU data is incorporated to provide prior and scale information for the visual localization algorithm. More accurate visual pose is estimated by minimizing multiple residuals function. The environment point and line feature map, dense map and navigation map are then constructed. To overcome the disadvantages of traditional line feature extraction algorithms, which are easy to cause detection of a large number of short and similar line segment features and over-segmentation of line segments in complex scenes. The strategies of length suppression, near line merging and short line chaining are introduced, and an improved FLD algorithm is proposed to reduce the mismatch rate of the line features, and the running speed of the algorithm proposed is more than twice of that of the LSD algorithm. By comparing the simulation results obtained from multiple groups of public datasets and real-world weak texture scenes, it can be seen that the proposed algorithm can obtain richer environment maps with great positioning accuracy and good robustness.
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    Plasma synthetic jet actuator for flow control: Review
    ZHOU Yan, LUO Zhenbing, WANG Lin, XIA Zhixun, GAO Tianxiang, XIE Wei, DENG Xiong, PENG Wenqiang, CHENG Pan
    ACTA AERONAUTICAET ASTRONAUTICA SINICA    2022, 43 (3): 25027-025027.   DOI: 10.7527/S1000-6893.2020.25027
    Abstract711)   HTML27)    PDF(pc) (23280KB)(487)       Save
    Plasma Synthetic Jet (PSJ) actuators are a type of flow control device which generates high-temperature and high-speed zero-net mass flux jets using gas heating and pressurization of arc discharge in a semi-closed chamber. With advantages of high jet velocity, strong boundary layer penetration ability, fast response, wide actuation bandwidth and no moving parts, this device shows promising applications as a novel active flow control actuator. This paper presents a review of the recent progress in the research on plasma synthetic jet actuators. The optimization designs of plasma synthetic jet actuator systems for improving control authority, increasing energy efficiency and expanding environmental adaptability are summarized, the innovative research methods used in the investigations introduced, and the energy efficiency characteristics and the influence of parameters of the actuator presented. The applications of plasma synthetic jet actuators in various situations such as crossflow interaction, flow separation control, shock control and control of shock wave/turbulent boundary layer interaction are then reviewed. The interaction mechanisms between plasma synthetic jet and crossflow, separation bubbles and shock waves are discussed, followed by the analysis of the effects of momentum injection, blast waves and local heating of plasma synthetic jet in active flow control. The research trends are finally discussed.
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    Current status, challenges and opportunities of civil aero-engine diagnostics & health management Ⅰ: Diagnosis and prognosis of engine gas path, mechanical and FADEC
    CAO Ming, HUANG Jinquan, ZHOU Jian, CHEN Xuefeng, LU Feng, WEI Fang
    ACTA AERONAUTICAET ASTRONAUTICA SINICA    2022, 43 (9): 625573-625573.   DOI: 10.7527/S1000-6893.2021.25573
    Abstract688)   HTML35)    PDF(pc) (7660KB)(550)       Save
    The engineering advancements during the last two decades have presented opportunities as well as challenges for the Engine Health Management (EHM) system development of civil aero-engines. This R&D review provides an in-depth discussion on EHM needs, gaps and potential solutions/future R&D development directions, focusing on the "up-stream" EHM development modules: Engine gas path diagnostics and prognostics, mechanical diagnostics and prognostics, FADEC diagnostics and prognostics. Results shows the Unscented Kalman Filter (UKF) method and deep-learning neural networks have shown promises on improving the engine gas path diagnostics accuracy; composite fans have found widespread applications in turbo-fan engines; powder metallurgy has seen more and more applications on fabricating aero-engine parts with complex shapes; the accuracies of metal particle sensing technologies have witnessed significant improvements, with technology readiness level matching the aero-engine needs, and paved the way for fusion diagnostics with vibration signal. The result also show that electrification and intelligentization trends of FADEC system presents new challenges for the diagnostics of the traditionally centralized control architecture.
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    Multi-objective optimization method for aircraft tolerance allocation based on Monte Carlo-adaptive differential evolution algorithm
    JING Tao, TIAN Xitian
    ACTA AERONAUTICAET ASTRONAUTICA SINICA    2022, 43 (3): 425278-425278.   DOI: 10.7527/S1000-6893.2021.25278
    Abstract685)   HTML11)    PDF(pc) (5156KB)(152)       Save
    The optimization method of the general tolerance allocation model has precision errors and low efficiency due to nonlinear stack-up of assembly deviations in the assembly process of complicated aircraft components.In this paper, a novel multi-objective optimization method of tolerance allocation model is proposed.First, a tolerance allocation model for the manufacturing cost, assembly performance, and quality loss of the aircraft is constructed based on alternative processes.A multi-objective optimization model is established using the optimization theory.Then, a multi-objective optimization strategy is proposed based on the Monte Carlo-adaptive differential evolution algorithm, in which the non-linear relationship model of deviation is extracted based on the graph tree model of assembly deviation propagation.Based on the non-linear relationship model extracted, the initial samples are pre-processed using the Monte Carle method to improve the diversity of the initial population.In the mutation stage in the adaptive differential evolution algorithm, the Lévy flight probability distribution is used to improve the global search efficiency and robustness.The tolerance allocation method is verified by assembly of the aircraft boarding gate components.The results demonstrate that the proposed method can optimize tolerance allocation more accurately and efficiently.Compared with the initial tolerance allocation, the optimized tolerance allocation results in reduction of the manufacturing cost by 21.78% and the quality loss by 11.12%, and increase of assembly performance by 12.28%.
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    Cumulative damage index model and service reliability evaluation of turbine blade
    LEI Shiying, SUN Jianzhong, LIU He
    ACTA AERONAUTICAET ASTRONAUTICA SINICA    2022, 43 (3): 225064-225064.   DOI: 10.7527/S1000-6893.2021.25064
    Abstract678)   HTML10)    PDF(pc) (8064KB)(163)       Save
    High Pressure Turbine (HPT) blades are one of the key structural parts of civil aviation engines, directly related to the performance, reliability and service life of the engine.This paper proposes a service reliability assessment method for HPT blades.The blade creep damage is evaluated based on historical flight condition data under service conditions, combined with the engine performance model, the stress and temperature calculation model of the key point, and the creep damage assessment model.After calculation, and in consideration of the multi-modal data under service conditions, a cumulative damage index model is established for creep failure, and the service reliability of the blade is evaluated by fusing the historical covariate information.The simulation results show that the creep cumulative damage index defined in the article can make full use of the historical usage information, state parameters and truncated failure data of the engine under service conditions to realize the service reliability assessment and remaining life prediction of the turbine blades under specific service conditions.Compared with traditional reliability analysis methods, the cumulative damage index prediction model can provide more reliable evaluation results based on the service conditions of a single aircraft and better support for aero engine operation risk assessment and condition-based maintenance decision-making.
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    Knowledge graph construction technology and its application in aircraft power system fault diagnosis
    NIE Tongpan, ZENG Jiyan, CHENG Yujie, MA Liang
    ACTA AERONAUTICAET ASTRONAUTICA SINICA    2022, 43 (8): 625499-625499.   DOI: 10.7527/S1000-6893.2021.25499
    Abstract635)   HTML14)    PDF(pc) (9686KB)(333)       Save
    The electrification degree of airborne equipment continues to increase with the development of science and technology. Owning to this, failure in aircraft power system is posing an increasing threat to flight safety, which granted necessity to fast and accurate health state assessment. The commonly used data-driven fault diagnosis method cannot make use of expert knowledge. Meanwhile, the result of data-driven method is lack of interpretability, and therefore, limits its application in real practice. Knowledge graph has the ability to normalize the storage of such unstructured data as expert knowledge and use it for diagnosis. Moreover, knowledge graph can utilize the unstructured knowledge and supply a reasonable explanation for the cause of the failure. However, in the field of fault diagnosis, there are still few studies on the application of knowledge graph technology. In this article, a knowledge graph construction and application technology for aircraft power system fault diagnosis is proposed. First, ontology of the knowledge graph, which specifies the entity and relation types in the knowledge graph, is constructed based on the priori expert knowledge. Then, Bi-Directional Long Short-Term Memory (Bi-LSTM) method is trained with BMEO-tagged corpus and utilized to extract entities from the unstructured texts. After that, an attention-based Bi-LSTM algorithm is trained with relation-tagged corpus and then utilized to realize relation extraction. Finally, the knowledge graph for aircraft power system fault diagnosis is constructed based on the extracted entities and relations. A fault isolation manual of aircraft power system is used as raw corpus data in the case study to verify the effectiveness of the proposed method by the indicators of precision and recall. Based on the knowledge graph, intelligent searching, recommending and Q & A are realized, which strongly support the application prospect of knowledge graph in the field of fault diagnosis.
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    MUSCL and WENO schemes problems generated by dimension splitting approach
    LIU Jun, HAN Fang, WEI Yanxin
    ACTA AERONAUTICAET ASTRONAUTICA SINICA    2022, 43 (3): 125009-125009.   DOI: 10.7527/S1000-6893.2021.25009
    Abstract619)   HTML8)    PDF(pc) (7370KB)(125)       Save
    This paper first discuss the difference between finite difference method and finite volume method, subsequently supplementing new arguments for the existence of differences in the boundary condition treatment and grid requirements between these two methods based on the existing literature.The calculation process of the interface flux of the control volume by dimension-by-dimension derived MUSCL and WENO schemes is further introduced.Since the direct application of these schemes to the Gaussian integral finite volume method is considered not rigorous enough, it is concluded that the MUSCL scheme and WENO scheme constructed by the dimension splitting method do not belong to the Gaussian integral finite volume method, while the definition of "integral scheme" can more accurately reflect the characteristics of these schemes.In addition, the reasons for the inability of the MUSCL and WENO schemes to guarantee conservation in the curvilinear coordinate system are discussed, and the elimination methods briefly introduced.Finally, research results obtained according to the viewpoint of this paper are briefly presented.
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    Detection method of defects in automatic fiber placement based on fusion of infrared and visible images
    KANG Shuo, KE Zhenzheng, WANG Xuan, ZHU Weidong
    ACTA AERONAUTICAET ASTRONAUTICA SINICA    2022, 43 (3): 425187-425187.   DOI: 10.7527/S1000-6893.2021.25187
    Abstract618)   HTML5)    PDF(pc) (11487KB)(184)       Save
    To improve the quality of Automatic Fiber Placement (AFP), this paper analyzes the limitations of single spectrum detection technology in the field of visual inspection, and proposes a method based on deep learning for defect detection by fusion of infrared and visible images to realize detection, location and classification of fiber placement defects.According to the difference between the defects in thermal infrared image and visible image, the feature fusion network is used to fuse the two kinds of spectral information to improve the detection effect.To improve the detection speed, the single-stage detection network is used as the detection framework.We analyze the shortcomings of anchor-based method in the single-stage detection network according to the characteristics of seriously uneven distribution of length-width ratio of fiber defects, and propose a detection method with anchor-free network, in which an improved feature pyramid network structure is added for multi-scale prediction.Using mean Average Precision (mAP) as the measurement index, the experimental results improved by 6.30%, 6.64% and 1.02% respectively compared with single spectrum detection method, anchor-based detection method and the detection method without improved feature pyramid structure.The detection time of each 608 pixels×608 pixels image is less than 20 ms after acceleration by Tensor RT, which meets the demand of real-time detection.The average recall of detection is more than 88%, and the average precision is more than 82%, which meets the demand of production accuracy.The data of this paper is verified by off-line detection on the test-bed, and is tested online on large gantry AFP equipment.
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    Application of pulse compression in electromagnetic ultrasonic guided wave detection of aluminum sheet
    SHI Wenze, CHENG Jinjie, HU Shuozhen, LU Chao, CHEN Yao
    ACTA AERONAUTICAET ASTRONAUTICA SINICA    2022, 43 (3): 425063-425063.   DOI: 10.7527/S1000-6893.2021.25063
    Abstract593)   HTML15)    PDF(pc) (8427KB)(88)       Save
    Aiming at the problem of poor Signal-to-Noise Ratio (SNR) of ultrasonic echoes caused by low energy conversion efficiency of Electromagnetic Ultrasonic Transducer (EMAT), the design of matching filter and sidelobe suppression filter and their implementation in electromagnetic ultrasonic detection were discussed based on phase-coded pulse compression technology.A typical two-phase coded signal, Barker code, was selected as the excitation signal.The effect of barker code signals with different lengths and carrier cycles on the pulse compression effect of guided wave EMAT detection was analyzed, and the effect of sidelobe suppression algorithm was also studied.We selected a 7075 aluminum alloy sheet with four manually prefabricated defects as the testing object, a SH0 mode guided wave EMAT was used to compare the SNRs of defect echo signals obtained by single-frequency sinusoidal signal excitation method and Barker code pulse compression technology.The results show that compared with single-frequency signal excitation, the SNR of the ultrasonic signal after Barker code pulse compression was increased by at least 7.2 dB.With Barker code pulse compression technology, a defect of small size (long×wide×deep is 10.0 mm×1.0 mm×0.25 mm) can be effectively detected, which cannot be detected with the single-frequency sinusoidal signal excitation method.With the application of Barker code pulse compression technology to guided wave EMAT detection, the increase in EMAT lift-off and the reduction in the number of synchronous averages can be realized, and requirements of online and rapid inspection can be met.
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    Multi-region integrated design and optimization of concentrated-force diffusion component in heavy-lift launch vehicle
    WANG Zhixiang, LEI Yongjun, DUAN Jingbo, OUYANG Xing, ZHANG Dapeng, WANG Jie
    ACTA AERONAUTICAET ASTRONAUTICA SINICA    2022, 43 (3): 225135-225135.   DOI: 10.7527/S1000-6893.2021.25135
    Abstract592)   HTML4)    PDF(pc) (9343KB)(305)       Save
    To improve the load-carrying capacity and concentrated-force diffusion performance, a novel integrated design method combining variable profile, proportional layout and multi-region design, along with optimization model based on the static analysis and engineering estimat method is proposed for the optimal design of the concentrated-force diffusion component in the heavy-lift launch vehicle.parametric finite element model is for the concentrated-force diffusion component, of which the load-carrying capacity and concentrated-force diffusion performance are analyzed.According to the structural form and load-carrying characteristic of the concentrated-force diffusion component, an integrated design method of variable thickness, variable profiles and proportional layout is proposed for the detailed design.To comprehensively improve the load-carrying capacity and concentrated-force diffusion performance, an optimization model based on the static analysis and engineering estimat method is solved by the simulated annealing method, thereby an optimized structure with weight reduction.The comparison results show that it beneficial to improve the load-carrying efficiency and concentrated-force diffusion performance the auxiliary-beams/stringers on both sides of the strap-on devices densely close to strap-on devices the auxiliary-beams between strap-on devices densely far away from strap-on devices, main-beams with variable profile and skin with variable thickness.The effectiveness and superiority of the proposed integrated design method and optimization model are validated for the prospect of engineering application.
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    Passive direction finding algorithm of projectile based on short baseline sensor array
    QU Bingnan, JIANG Ping, ZHAO Luyang, LI Fengrong, WANG Yingguan
    ACTA AERONAUTICAET ASTRONAUTICA SINICA    2022, 43 (3): 325139-325139.   DOI: 10.7527/S1000-6893.2021.25139
    Abstract583)   HTML6)    PDF(pc) (7201KB)(91)       Save
    Existing non-source passive detection technologies based on angle estimation cannot meet the requirement for high-precision target direction finding in the far field, and existing passive detection sensor arrays are limited by requirement for large-scale surround deployment in the battlefield. To overcome these problems, a passive direction finding method, which is unaffected by the wave velocity, is proposed based on the short baseline sensor array, by combing the Rayleigh wave extraction method based on Empirical Mode Decomposition (EMD) and short-term energy characteristic analysis and the time delay hyperbolic positioning model. First, after analyzing the signal characteristics of the ground motion signals obtained by the sensor array, an adaptive decomposition and denoising model is constructed based on EMD, and a method for extracting Rayleigh wave components is proposed based on short-term energy characteristics of the signal. Second, based on the estimated time delay of wave joint correlation calculation, a time delay hyperbolic model is constructed based on the TDOA algorithm, and a DFA-WV algorithm based on the four-element cross short baseline sensor array is proposed to realize high-precision direction finding of the projectile signal without wave velocity estimation. Finally, the algorithm model proposed is verified in simulation and live-fire tests at the range. The results show that the Rayleigh wave extraction method proposed can provide high precision estimation of time delay, and the DFA-WV direction finding algorithm can eliminate the influence of estimation of wave velocity on direction finding results. Compared to the Chan algorithm and the improved MPR algorithm, the method proposed has higher direction finding performance and low computational complexity, and is thus applicable in projectile target direction finding in the actual field range.
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    Optimum design of wind tunnel test model for compliant morphing trailing edge
    ZHANG Zhenkai, JIA Sijia, SONG Chen, YANG Chao
    ACTA AERONAUTICAET ASTRONAUTICA SINICA    2022, 43 (3): 226071-226071.   DOI: 10.7527/S1000-6893.2021.26071
    Abstract581)   HTML10)    PDF(pc) (9995KB)(147)       Save
    In this paper, optimal size parameters are explored for a compliant morphing trailing edge device with high deformation accuracy. This device transmits force and movement through elastic deformation, and includes an actuator, and an integral skin-beams structural. A systematical design framework is proposed in order to find the optimal actuating and structural size parameters for a morphing trailing edge under a given structural topology. This framework consists of a shape parameterization for morphing trailing edge wing, aerodynamic shape optimization tool, and structural parameter optimization methods. Geometric nonlinearity is considered when solving structural large deformation. Comparative studies have shown that the Least Square Error distance cannot capture the local disturbance, while the Fréchet distance can well control the maximum deformation error, needs fewer iterations, and can obtain better results with higher overall deformation accuracy. Numerical simulations verify the effectiveness of the proposed optimization method. The optimal design of four initial structures with different topology are obtained, with a maxi-mum improvement for deformation accuracy of 91%. Finally, a prototype of compliant morphing trailing edge is realized through additive manufacturing, which has a deformability of 22.5° downward and 7.5° upwards.
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    Adaptive decoupling control for a class of spinning rockets considering actuator dynamics
    SHI Zhongjiao, ZHU Huajie, ZHAO Liangyu, LIU Zhijie
    ACTA AERONAUTICAET ASTRONAUTICA SINICA    2022, 43 (3): 325068-325068.   DOI: 10.7527/S1000-6893.2021.25068
    Abstract564)   HTML10)    PDF(pc) (4425KB)(151)       Save
    An adaptive decoupling control method considering aerodynamic uncertainty and actuator dynamics is proposed to solve the strong coupling problem caused by aerodynamic, inertial and control cross-coupling.Considering a type of canard controlled spinning rockets, an acceleration dynamic model considering actuator dynamics is established under the non-rolling body frame.Using the model reference adaptive control method as the basic framework, the tracking error integral is extended to the controlled system to improve the tracking performance of the closed-loop system.The error signal between the input and output of the actuator is fed back into the reference model to realize the decoupling between the pitch and yaw channels.Theoretical analysis and numerical simulation show the effectiveness of the proposed method.The simulation results show that the adaptive decoupling controller developed in our study can ensure stability of the closed-loop system and realize the decoupling between the pitch and yaw channels.
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