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3rd IEEE International Conference on Civil aviation Safety and Information technology, ICCASIT 2021

作者： Li, Fan Sun, Hong Du, Dong Zhao, Mingda Chen, Chen Key Laboratory of Flight Techniques and Flight Safety CAAC Civil Aviation Flight University of China Guanghan China Department of Flight Technology Management China Eastern Airlines Shanghai China College of Computer Science Civil Aviation Flight University of China Guanghan China

ISBN: (纸本)9781665425186

Hard landing prediction is one of the most typical landing safety incidents analyses, which is the crucial part in the flight operational quality assurance of civil aviation. Although prediction performances based on quick access recorder data have been improved using machine learning and deep learning methods, there have been few studies on hard landing predictions using SD card data from general aviation aircraft recording systems. To address the problem of normal acceleration prediction in hard landing analyses, a novel sequence to sequence prediction method was developed based on SD card flight data. First, the original data was preprocessed and then an attention mechanism-based GRU encoder-decoder model was designed for the normal acceleration sequence predictions. Experiments were conducted based on real SD card flight samples for training flight aircrafts to compare the proposed method with previous approaches, the comparison results from which showed that even when using the relatively low sampling rate flight recording data, the proposed method had significant performance improvements for general aviation aircraft landing safety incidents analyses. © 2021 IEEE

关键词： Forecasting

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Real-time synchronous detection of wind and aerosol using a coherent lidar

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Chinese Optics Letters 2025年第1期23卷 55-61页

作者： Yue Shi Xiong Luo Peiyu Sun Jihui Dong Lei Tang Jie Zhou Ke Wang Chunli Chen Yunshi Wang Dingfu Zhou Southwest Institute of Technical Physics Chengdu 610041China Science College Civil Aviation Flight University of ChinaGuanghan 618307China Lidar and Device Laboratory Southwest Institute of Technical PhysicsChengdu 610041China Key Laboratory of Laser Device Technology of China North Industries Group Corporation Limited Chengdu 610041China China Research and Development Academy of Machinery Equipment Beijing 100089China

Coherent lidar(CL)addresses existing constraints in CL data products by enabling simultaneous observation of multiple meteorological parameters such as cloud height,extinction coefficient,aerosol concentration,and wind field evaluation.A detailed analysis of CL echo signals was performed at a wavelength of 1550 nm,enabling accurate measurements of cloud height and aerosol *** data analyses and validation tests were conducted,aligning them with a 532 nm direct aerosol lidar(AL).The assessments of the aerosol extinction coefficient demonstrated notable *** underscores the potential of advanced CL for providing prolonged and consistent observations across diverse meteorological conditions.

关键词： coherent lidar aerosol extinction coefficient aerosol concentration wind

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Geometric Tracking Control of A Quadrotor with Tilted Propellers

Geometric Tracking Control of A Quadrotor with Tilted Propel...

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IEEE/ASME (AIM) International Conference on Advanced Intelligent Mechatronics

作者： Shangkun Zhong Xinyu Cai Zhao Ma Yibo Ding Shaohui Foong Aviation Key Laboratory of Science and Technology on Flight Control AVIC Xi’an Automatic Flight Control Research Institute Xi’an Engineering Product Development (EPD) Pillar Singapore University of Technology and Design (SUTD) Singapore School of Astronautics Northwestern Polytechnical University Xi’an

ISBN: (数字)9798350355369

ISBN: (纸本)9798350355376

This paper considers the control of the quadrotors with the unaligned thrust. Unlike the conventional quadrotor, the translational dynamics of these vehicles are sophisticatedly correlated with the rotational dynamics. This arises because the bearing of the total thrust in the body frame varies, in contrast to the unidirectional total thrust of regular quadrotors. This complexity poses a significant challenge to the control design for the quadrotor with the unaligned propellers. To address the challenge, we propose a geometric tracking control method that compensates for the thrust direction variation by incorporating additional vehicle inclination. The nonlinear tracking controller is characterized by defining the tracking error on the special Euclidean group SE(3). Through Lyapunov analysis, we proved almost globally exponential stability of zero equilibrium of the error dynamics. Simulation results illustrate the success of the proposed tracking control in achieving spiral trajectory tracking and recovering from the initial upside-down orientation for quadrotors with distinct propeller alignment configurations.

关键词： Spirals Mechatronics Propellers Trajectory tracking Simulation Dynamics Stability analysis

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ADRC based on modified ESO for nonlinear time-varying system with impulsive disturbance

ADRC based on modified ESO for nonlinear time-varying system...

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第43届中国控制会议

作者： Xiangyang Li Jianer Bai Jian Huang Bingbing Wang Senping Tian Key Laboratory of Autonomous Systems and Network Control Ministry of Education School of Automation Science and Engineering South China University of Technology Kunming Shipborne Equipment Research and Test Center Aviation College Changji University

ISBN: (数字)9789887581581

ISBN: (纸本)9798350366907

The extended state observer(ESO) is the core of Active disturbance rejection control(ADRC) methodology. The paper proposes a new modified ESO which can overcome the initial peaking phenomenon and improve to adapt the abrupt change in disturbance change and keep the control system stable and enough accuracy. The adjustable parameter in modified ESO can be set according to the desired ESO performance which is hard to satisfy by just adjusting the bandwidth oof ESO. Simulations show that the proposed ADRC based on modified ESO has the same stable tracking performance and more effective to overcome initial peaking phenomenon and adapt setpoint and disturbance abrupt change.

关键词： Active disturbance rejection control(ADRC) extended state observer(ESO) nonlinear time-varying system impulsive disturbance

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Short-term multi-step-ahead sector-based traffic flow prediction based on the attention-enhanced graph convolutional LSTM network (AGC-LSTM)

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Neural Computing and Applications 2024年 1-20页

作者： Zhang, Ying Xu, Shimin Zhang, Linghui Jiang, Weiwei Alam, Sameer Xue, Dabin College of General Aviation and Flight Nanjing University of Aeronautics and Astronautics Nanjing China State Key Laboratory of Air Traffic Management System Nanjing China College of Computer Science and Technology Nanjing University of Aeronautics and Astronautics Nanjing China School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing China Air Traffic Management Research Institute School of Mechanical & ampAerospace Engineering Nanyang Technological University Singapore Singapore Department of Land Surveying and Geo-Informatics The Hong Kong Polytechnic University Hong Kong

Accurate sector-based air traffic flow predictions are essential for ensuring the safety and efficiency of the air traffic management (ATM) system. However, due to the inherent spatial and temporal dependencies of air traffic flow, it is still a challenging problem. To solve this problem, some methods are proposed considering the relationship between sectors, while the complicated spatiotemporal dynamics and interdependencies between traffic flow of route segments related to the sector are not taken into account. To address this challenge, the attention-enhanced graph convolutional long short-term memory network (AGC-LSTM) model is applied to improve the short-term sector-based traffic flow prediction, in which spatial structures of route segments related to the sector are considered for the first time. Specifically, the graph convolutional networks (GCN)-LSTM network model was employed to capture spatiotemporal dependencies of the flight data, and the attention mechanism is designed to concentrate on the informative features from key nodes at each layer of the AGC-LSTM model. The proposed model is evaluated through a case study of the typical enroute sector in the central–southern region of China. The prediction results show that MAE reduces by 14.4% compared to the best performing GCN-LSTM model among the other five models. Furthermore, the study involves comparative analyses to assess the influence of route segment range, input and output sequence lengths, and time granularities on prediction performance. This study helps air traffic managers predict flight situations more accurately and avoid implementing overly conservative or excessively aggressive flow management measures for the sectors. © The Author(s) 2024.

关键词： Forecasting

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Neural Rendering and Flow-assisted Unsupervised Multi-view Stereo for Real-time Monocular Tracking and Scene Perception

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IEEE Transactions on Automation science and Engineering 2025年

作者： Tong, Kevin W. Cai, Yandong Jie, Yu-Wen Duan, Ya Hou, Yuhong Wu, Edmond Q. Nanjing University of Posts and Telecommunications College of Automation College of Artificial Intelligence Nanjing210023 China Ministry of Education Key Laboratory of Social Computing and Cognitive Intelligence Dalian University of Technology Dalian116024 China Shanxi University School of Automation and Software Engineering Shanxi 237016 China Flight Test Technology and Engineering Center of the Chinese Flight Test Establishment Xian710089 China China Civil Aviation Shanghai Aircraft Airworthiness Certification Center Shanghai200335 China Shanghai Jiao Tong University Department of Computer Science and Engineering Shanghai200240 China

The existing camera tracking and perception methods mainly rely on sparse SLAM, which limits the dense perception ability of the scene and affects the reliability of auxiliary decision-making. Different from this, this work proposes a real-time tracking and unsupervised dense sensing framework. Firstly, the dense depth value of the scene is predicted by unsupervised multi-view stereo to remove the dependence on labeled data. Then, the quality of synthetic pseudo-reference image is quantified according to the predicted depth map and used as a weighted guidance to train the unsupervised model, thus reducing the ambiguity of feature matching in areas such as specular reflection. Moreover, the sparse optical flow of the keyframes is solved by real-time and robust ORB feature matching operator, which assists the high-precision training of unsupervised depth inference model. To increase the prediction accuracy of occluded area, a novel rendering consistency loss via neural radiance fields is designed to constrain the geometric characteristics of object surface. Finally, dense direct image alignment is performed from a global model to improve the tracking robustness, which is incrementally constructed from dense depth prediction. Extensive experiments on synthetic datasets and real datasets validate the effectiveness and practicability of the proposed work, which is an effective supplement to the existing SLAM work. © 2025 IEEE.

关键词： Stereo image processing

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Relationships between Cloud Droplet Spectral Relative Dispersion and Entrainment Rate and Their Impacting Factors

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Advances in Atmospheric sciences 2022年第12期39卷 2087-2106,I0016-I0019页

作者： Shi LUO Chunsong LU Yangang LIU Yaohui LI Wenhua GAO Yujun QIU Xiaoqi XU Junjun LI Lei ZHU Yuan WANG Junjie WU Xinlin YANG College of Aviation Meteorology Civil Aviation Flight University of ChinaGuanghan 618307China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD)/Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration Nanjing University of Information Science&TechnologyNanjing 210044China Environmental and Climate Sciences Department Brookhaven National LaboratoryUptonNew York 11973US State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China Nanjing Joint Institute for Atmospheric Sciences Nanjing 210019China Collaborative Innovation Center for Western Ecological Safety Lanzhou UniversityLanzhou 730000China

Cloud microphysical properties are significantly affected by entrainment and mixing ***,it is unclear how the entrainment rate affects the relative dispersion of cloud droplet size ***,the relationship between relative dispersion and entrainment rate was found to be positive or *** reconcile the contrasting relationships,the Explicit Mixing Parcel Model is used to determine the underlying *** evaporation is dominated by small droplets,and the entrained environmental air is further saturated during mixing,the relationship is ***,when the evaporation of big droplets is dominant,the relationship is *** or not the cloud condensation nuclei are considered in the entrained environmental air is a key factor as condensation on the entrained condensation nuclei is the main source of small ***,if cloud condensation nuclei are not entrained,the relationship is *** cloud condensation nuclei are entrained,the relationship is dependent on many other *** values of vertical velocity,relative humidity of environmental air,and liquid water content,and low values of droplet number concentration,are more likely to cause the negative relationship since new saturation is easier to achieve by evaporation of small ***,the signs of the relationship are not strongly affected by the turbulence dissipation rate,but the higher dissipation rate causes the positive relationship to be more significant for a larger entrainment rate.A conceptual model is proposed to reconcile the contrasting *** work enhances the understanding of relative dispersion and lays a foundation for the quantification of entrainment-mixing mechanisms.

关键词： clouds entrainment rate relative dispersion of cloud droplet size distribution mixing and evaporation

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Investigation on the electro-thermal coupled catastrophic mechanisms in parallel modules of lithium-ion batteries

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Journal of Energy Storage 2025年 127卷

作者： He, Yuanhua Liang, Jiaxin Jin, Jianquan Li, Zitong Huang, Jiang College of Civil Aviation Safety Engineering Civil Aviation Flight University of China Sichuan Guanghan618307 China Civil Aircraft Fire Science and Safety Engineering Key Laboratory of Sichuan Province Guanghan618307 China Sichuan Key Technology Engineering Research Center for All-electric Navigable Aircraft Sichuan Guanghan618307 China

Thermal disasters in parallel modules of lithium-ion batteries trigger abnormal electro-thermal behaviours, posing substantial safety risks. The electro-thermal coupling mechanism involved in thermal runaway evolution remains unclear. This study investigated the aforementioned mechanism during thermal runaway in non-operational and operational parallel modules by analysing dynamic changes in electrical and thermal parameters. Under non-operational conditions, the peak thermal runaway temperature of a directly heated cell reached 434.64 °C, exceeding that of the indirectly heated cell by 40.87 °C. The maximum short-circuit current was 497.56 A, amplifying internal exothermic reactions. Therefore, the peak electrode temperatures and maximum surface temperature rise rates of the directly heated cell were remarkably higher than those of a single cell. Under operational conditions at 1–3C discharge rates, the short-circuit currents decreased sequentially to 420.83, 357.09, and 309.53 A, accompanied by a progressive reduction in peak temperature differences between cells from 35.13 °C to 7.35 °C. This reduction is attributed to the charge depletion state, which limits energy transfer between cells. These results demonstrate that operational modules experience less severe electro-thermal coupling hazards compared with non-operational ones. An electro-thermal coupling model, incorporating Ohmic, reversible and Joule heating and the discharge rate, revealed that the discharge current heat and short-circuit current heat were positively and negatively, respectively, correlated with the discharge rate. These findings improve the understanding of electro-thermal coupling in parallel modules of lithium-ion batteries, providing valuable insights for their safe design. © 2025 Elsevier Ltd

关键词： Short circuit currents

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Stability Control and Trajectory Optimization of Tail-Sitter VTOL UAV Takeoff / Landing Incorporating Bionic technology

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Transactions of Nanjing University of Aeronautics and Astronautics 2024年第3期41卷 263-277页

作者： Qi, Hao Li, Qingyang Wu, Jiayue Peng, Yiming Nie, Hong Wei, Xiaohui State Key Laboratory of Mechanics and Control for Aerospace Structures Nanjing University of Aeronautics and Astronautics Nanjing210016 China Key Laboratory of Fundamental Science for National Defense Advanced Design Technology of Flight Vehicle Nanjing University of Aeronautics and Astronautics Nanjing210016 China China Aviation Power Plant Research Institute Zhuzhou412002 China School of Automation Science and Electrical Engineering Beihang University Beijing100191 China

The tail-sitter vertical takeoff / landing(VTOL)unmanned aerial vehicle(UAV)exhibits poor stability and limited compatibility with traditional landing gears. To address the aforementioned issues, a novel landing gear incorporating free-tail technology is proposed. The landing gear adopts a tandem multi-stage structure, which can ensure the length of the tail force arm in cruise condition while lowering the fuselage altitude. Furthermore, the dynamic landing process is regulated through the employment of virtual centroid force distribution techniques, streamlining the control process and facilitating seamless trajectory optimization during mode transition. Based on the single-point dataset of the cat center point, a neural network is used to train the landing gear control, which makes the landing gear adaptive takeoff and landing speed and accuracy effectively improved. Subsequently, multi-objective optimization and similarity conversion are executed in conjunction with parameter requirements of different modes of the UAV, effectively enhancing landing adaptability and stability of the tail-sitter VTOL UAV. © 2024 Nanjing University of Aeronautics an Astronautics. All rights reserved.

关键词： Drones

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A Novel Perturbation-Theory-Based Approach for Free Vibrations of Bi-Directional Functionally Graded Porous Beams with a New Bi-Directional Pore Distribution Pattern

SSRN

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SSRN 2024年

作者： Chen, Chen Zhou, Lilin Li, Daokui College of Aerospace Science and Engineering National University of Defense Technology Hunan Changsha410073 China Hunan Key Laboratory of Intelligent Planning and Simulation for Aerospace Missions Hunan Changsha410073 China Aviation Engineering Institute Civil Aviation Flight University of China Sichuan Guanghan618307 China

Porosity defects usually exist in the functionally graded material (FGM) due to the inherent deficiencies in the fabricating process. Omission and miscalculation of the defects possibly resulting in overpredicted load-carrying capacities. The current assumption of pore distribution ignores the influence of material gradient which is not accurate enough. A new hypothesis of a bi-directional (2D) FG porosity distribution pattern that closer to the observation is proposed to characterize the feature. Moreover, instead of the numerical method, this study pioneers a fresh thought of perturbation approach (PA) customized for solving the governing equations of the bi-directional functionally graded porous (2D FGP) beam for the first time. First, A new hypothesis of 2D porosity distribution pattern is proposed. Second, a free vibration model of the 2D FGP beam is established by the rule of mixture, Timoshenko beam theory, and Hamilton’s principle. Then, by applying the PA, the 2D FGP beam is equivalent to an even porous homogenous beam and a small material perturbation to facilitate the computation of natural frequencies. The results of high-precision show that the PA is adaptive and applicable. Finally, discussions and analyses are conducted. It is found that, the pore distribution pattern has a significant impact on the natural frequency. The frequency of the new 2D FGP beam decreases with the increase of the material gradient, the porosity coefficient, and the power-law indexes. The influence of pores can be ignored in a rough calculation once the pore distribution is observed to approach the proposed uneven pattern. © 2024, The Authors. All rights reserved.

关键词： Natural frequencies

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