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4th International Conference on Environmental sciences and Renewable Energy (ESRE)

作者： Zhao, Jing-Yu Chang, Jia-Ming Song, Jia-Jia Shu, Chi-Min 58 Yanta Mid. Rd. Shaanxi Xi’an710054 China Shaanxi Key Laboratory of Prevention and Control of Coal Fire XUST 58 Yanta Mid. Rd. Shaanxi Xi’an710054 China Graduate School of Engineering Science and Technology National Yunlin University of Science and Technology Yunlin64002 Taiwan

ISBN: (纸本)9789811994395

There are numerous safety problems of tailings pond in China, and overtopping dam break accidents occur frequently. Based on the mechanics of sediment movement, the influence of different particle sizes on the erosion rate of tailings dam in sediment laden flow was studied by means of indoor test and mathematical induction. The self-made test system for erosion characteristics and scouring process of soil slope under complex hydrodynamic conditions was used. Tailings of Nanchuan in Chongqing and Xiaoda Goose in Yunnan were used to screen out five different particle sizes (0.075, 0.106, 0.150, 0.250, and 0.425 mm) and proportioned into a sediment laden flow with a concentration of 5% for tailings erosion test. The average erosion rate was calculated and the line chart was drawn by measuring the erosion height and erosion time of tailings samples and repeating the test. The analysis drew the following conclusions: (1) With the same sediment concentration and flow velocity, the smaller the particle size was, the greater the erosion rate was. (2) The relationship curve between particle size and erosion rate showed that when the particle size changed from small to large, the gradient of erosion rate changed from large to small. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Particle size

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A Reinforcement Learning Method to Trajectory Design for Manned Lunar Mission via Reshaping Rewards

A Reinforcement Learning Method to Trajectory Design for Man...

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International Conference on Guidance, Navigation and control, ICGNC 2022

作者： Yang, Luyi Li, Haiyang Li, Xingyong Li, Zeyue Lu, Lin College of Aerospace Science and Engineering National University of Defense Technology Changsha410073 China Hunan Key Laboratory of Intelligent Planning and Simulation for Aerospace Missions Hunan Changsha410073 China

ISBN: (纸本)9789811966125

This paper applies the reinforcement learning (RL) to multi-stage impulsive trajectory design of the manned lunar mission. The manned spacecraft is modeled as the agent and the nonlinear dynamics in the cislunar space is the interaction environment of the agent. Then the Markov decision model is mathematically built for the spacecraft and the optimization goal is to minimize the total impulses in the whole mission. The Q-learning method is used to learn the optimal policy and to better train the agent to explore and exploit the environment, a reshaping reward is designed to improve the convergency and effectiveness of the algorithm. Numerical results give the integrated designs of the lunar transfer orbit, Earth transfer orbit and three-impulsive lunar injection/ejection orbit. The proposed reshaping reward function shows better performance compared with the non-reshaping reward. The conclusions could provide a reference for China’s future manned lunar project. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Reinforcement learning

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Accurate Monocular Pose Measurement for Aircraft Transportation Monitoring

Accurate Monocular Pose Measurement for Aircraft Transportat...

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2024 IEEE International Conference on Unmanned Systems, ICUS 2024

作者： Sun, Xiaoliang Zhang, Zhuo Bi, Daoming Guo, Liangchao Wang, Qiufu Chen, Lin College of Aerospace Science and Engineering National University of Defense Technology Changsha China Hunan Provincial Key Laboratory of Image Measurement and Vision Navigation Changsha China AVIC Shenyang Aircraft Design & Research Institute Shenyang China

ISBN: (纸本)9798350384185

Comprehensive statue monitoring is of great significance for aircraft safety and efficient transportation. This paper proposes an accurate and efficient monocular pose measurement method for aircraft transportation monitoring. The proposed method firstly models the aircraft using a sparse keypoint set for simplicity. Then, based on the simple representation, a trained neural network model is adapted to detect the keypoints from the input monocular image to build 2D-3D correspondences for pose measurement. Coarse pose estimation is got by solving a Perspective-n-Point problem based on the 2D-3D correspondences. For accurate pose measurement, this paper uses the contour feature to refine the pose measurement. The refinement is achieved via gradient orientation based template matching. Experimental results indicate that the proposed method achieves accurate and efficient monocular pose measurement for aircraft transportation monitoring. © 2024 IEEE.

关键词： Template matching

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Analysis on affecting factors of the ribbon fluctuation in Array-MRF 2

Analysis on affecting factors of the ribbon fluctuation in A...

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2022 2nd International Conference on Advanced Materials and Mechatronics, ICAMM 2022

作者： Tie, Guipeng Wang, Bo Shi, Feng Song, Ci Tian, Ye College of Intelligence Science and Technology National University of Defense Technology 109 Deya Road Hunan Changsha410073 China Hunan Key Laboratory of Ultra-Precision Machining Technology Hunan Changsha410073 China Laboratory of Science and Technology on Integrated Logistics Support National University of Defense Technology 109 Deya Road Hunan Changsha410073 China

Large aperture planar optical elements are required in high power laser systems, and the mid-spatial frequency error of the surface of the high-power laser component will affect the normal operation of the high-power laser system. In recent years, there are many new MRF devices, but these devices only improve the removal efficiency of polishing materials and ignore the stability of MRF tools. As we all know, the fluctuation of the MRF polishing ribbon will affect the stability of the removal function, which will make the surface of the processed component produce the mid-spatial frequency error. Therefore, based on the array magnetorheological pole structure newly developed in our laboratory, this paper tests its magnetic field distribution and studies the influencing factors of array magnetorheological ribbon fluctuation. Based on the magnetic field force, the effects of magnetorheological fluid flow, polishing wheel speed, and magnetic pole structure on ribbon fluctuation are analyzed. Finally, by using the improved array magnetorheological device to obtain a stable removal function, the volume removal efficiency of fused silica reaches 0.022mm3/min, which verifies the feasibility of the improved device and doubles the removal efficiency of magnetorheological finishing of a single ribbon. Therefore, we use controlled magnetorheological processing flow and speed to control ribbon fluctuations and designing the magnetic pole structure, to control the stability of magnetorheological processing. © 2022 Institute of Physics Publishing. All rights reserved.

关键词： Magnetorheological fluids

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Adaptive Optimization Tracking control for an Unmanned Aerial Vehicle with Disturbance Suppression

Adaptive Optimization Tracking Control for an Unmanned Aeria...

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2024 IEEE International Conference on Systems, Man, and Cybernetics, SMC 2024

作者： Yang, Meiying Zhu, Hai Xia, Xingyu Liu, Zhe Yao, Wen Ai Institute Shanghai Jiao Tong University MoE Key Lab of Artificial Intelligence Shanghai China Defense Innovation Institute Chinese Academy of Military Science Beijing China Intelligent Game and Decision Laboratory Beijing China College of Aerospace Science and Engineering National University of Defense Technology Changsha China

ISBN: (纸本)9781665410205

Aiming at the tracking control for an unmanned aerial vehicle (UAV) with uncertainty and external disturbances, an adaptive optimization control method is proposed based on the backstepping method. The model uncertainty in the UAV is estimated using neural networks. Moreover, a disturbance observer is designed to estimate and counteract the disturbance in real-time. In addition, reinforcement learning (RL) is used to solve optimal problems and overcome the difficult issues of the Hamilton-Jacobi-Bellman (HJB) equation. In the controller design, dynamic surfaces are employed to avoid complex derivation issues in the virtual controller and improve operating efficiency. Furthermore, the stability of the UAV system is proved by the Lyapunov theory. Finally, the effectiveness and superiority of the proposed method are verified through numerical simulations and real-world experiments. © 2024 IEEE.

关键词： Disturbance rejection

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Exploration on molecular dynamics simulation methods of microscopic wetting process for coal dust

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International Journal of Coal science & technology 2021年第2期8卷 205-216页

作者： Qi Zhang Xinyi Chen Hetang Wang Chaohang Xu Key Laboratory of Gas and Fire Control for Coal Mines Ministry of EducationChina University of Mining and TechnologyXuzhou 221116China National Professional Center Laboratory of Basic Research of Mine Gas and Dust Control Technology China University of Mining and TechnologyXuzhou 221116China School of Safety Science and Emergency Management Wuhan University of TechnologyWuhan 430070China

Wet dust removal is one of the main technical measures in coal dust control,and coal dust wetting is the key factor to determine the effect of wet dust *** order to explore the micro-wetting process of coal dust,this paper uses molecular dynamics simulation to study the micro-wetting process of coal dust in different simulation *** molecular dynamics simulation was carried out under different ensemble,thermodynamic states as well as relaxation pretreatment methods,then the H_(2)O molecular layer and coal dust molecular layer in each simulation were quantitatively analyzed by relative *** research results show that a method for establishing molecular model of lignite is proposed and the 2D periodic surface structure is more *** surface system of coal-H_(2)O molecule is established by NVT aeration method,where the simulation result is close to the actual coal dust wetting *** simulation effect of medium and large coal dust-H_(2)O molecular system is better than that of small coal dust-H_(2)O molecular *** study provides a new solution for changing the empirical method of molecular dynamics simulation of coal system wetting and oversimplification of coal system.

关键词： Coal dust Wettability Molecular dynamics 2D periodic surfaces NVT ensemble

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Effects of particle size and oil-immersed concentration on the dust layer minimum ignition temperature and combustion characteristics of oil-immersed coal

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Journal of Thermal Analysis and Calorimetry 2024年第18期149卷 10297-10309页

作者： Luo, Zhenmin Yang, Yong Ding, Xuhan Luo, Chuanxu Zhang, Fan Zhang, Man Shu, Chi-Min School of Safety Science and Engineering Xi’an University of Science and Technology 58 Yanta Mid. Rd. Shaanxi Xi’an710054 China Shaanxi Key Laboratory of Prevention and Control of Coal Fire 58 Yanta Mid. Rd. Shaanxi Xi’an710054 China Shaanxi Engineering Research Centre for Industrial Process Safety and Emergency Rescue 58 Yanta Mid. Rd. Shaanxi Xi’an710054 China Department of Safety Health and Environmental Engineering National Yunlin University of Science and Technology 123 University Rd. Sec. 3 Yunlin Douliou64002 Taiwan

This paper studied the minimum ignition temperature of the dust layer (MITL) of oil-immersed coal and the heat effect and apparent activation energy (Ea) of raw coal and oil-immersed coal. Based upon the results, the addition of crude oil to coal could reduce the MITL, ameliorate the ignition sensitivity, and increase the heat effect of coal dust. The average Ea of oil-immersed coal was lower than that of raw coal. When there was a 10.8 mass% oil-immersed concentration of oil-immersed coal with the most acceptable particle size (≤ 75 μm), the MITL was 24.24% lower than that of raw coal. Furthermore, the exothermic value of oil-immersed coal was 26.67% higher than that of raw coal. Besides, the average Ea of oil-immersed coal was 26.8% lower than that of raw coal. The research herein is expected to improve people’s understanding of the thermal hazard characteristics of oil-immersed coal dust, reduce the risk of coal dust fires and explosions, and ensure production safety. Graphical Abstract: (Figure presented.) © Akadémiai Kiadó, Budapest, Hungary 2024.

关键词： Coal

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Ultrasonic Testing Method of Damage Degree of JHL-3 Substitute Material 20

Ultrasonic Testing Method of Damage Degree of JHL-3 Substitu...

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20th IEEE International Conference on Mechatronics and Automation, ICMA 2023

作者： Pan, Qinxue Zhou, Xiaoyou Xu, Xiaoyu Yu, Haoshen Xu, Jiaqi Beijing Institute of Technology Key Laboratory of Fundamental Science for National Defense for Advanced Machining Technology School of Mechanical Engineering 5 South Zhongguancun Street Haidian District Beijing China Beijing Institute of Control Engineering Fifth Research Institute of China Aerospace Science and Technology Corporation 16 South Third Street Zhongguancun Haidian District Beijing China

ISBN: (纸本)9798350320831

JHL-3 refers to a functional energetic material commonly used in aerospace solid propellants and weapon warheads. Its reliability is key to the performance and safety of the equipment. Therefore, this paper focuses on the definition of constitutive properties and the damage degree of such materials. We establish the damage-containing Z-W-T constitutive and introduce the ultrasonic nonlinear testing method to determine a corresponding relationship between the second-order relative nonlinear coefficient and the damage degree of the material under different damage states. This method was applied to confirm the same batch of grains, and the prediction error of the empirical model was obtained below 0.05. However, the error increased near the damage threshold (D = 0.301) where macroscopic cracks were generated. This confirms that the method is feasible for evaluating the damage degree of JHL-3 substitute materials. © 2023 IEEE.

关键词： Solid propellants

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Distribution of Miss Distance for Pursuit-Evasion Problem

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IEEE/CAA Journal of Automatica Sinica 2020年第4期7卷 1161-1168页

作者： Shengwen Xiang Hongqi Fan Qiang Fu the National Key Laboratory of Science and Technology on ATR National University of Defense TechnologyChangsha 410073China

Miss distance is a critical parameter of assessing the performance for highly maneuvering targets interception(HMTI). In a realistic terminal guidance system, the control of pursuer depends on the estimate of unknown state, thus the miss distance becomes a random variable with a prior unknown distribution. Currently, such a distribution is mainly evaluated by the method of Monte Carlo simulation. In this paper, by integrating the estimation error model of zero-effort miss distance(ZEM) obtained by our previous work, an analytic method for solving the distribution of miss distance is proposed, in which the system is presumed to use a bang-bang control strategy. By comparing with the results of Monte Carlo simulations under four different types of disturbances(maneuvers), the correctness of the proposed method is validated. Results of this paper provide a powerful tool for the design, analysis and performance evaluation of guidance system.

关键词： Analytical method bang-bang strategy miss distance distribution pursuit-evasion problem

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Enhancing Geolocation Accuracy of High-Altitude Airborne SAR Through Tropospheric Delay Compensation

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IEEE Transactions on Geoscience and Remote Sensing 2025年 63卷

作者： Xiang, Yaobing Sun, Yuli Lei, Lin Ji, Kefeng Kuang, Gangyao National University of Defense Technology State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System College of Electronic Science and Technology Changsha410073 China

Geolocation is a crucial step in the processing of synthetic aperture radar (SAR) images. High-altitude airborne SAR systems present unique geolocation challenges due to travelling long distances through the troposphere. However, the impact of tropospheric delay on geolocation is often overlooked in existing airborne SAR studies, which can lead to inaccuracies. To address this issue, we propose a new positioning method, the tropospheric delay-compensated range-Doppler (TDC-RD) model. The TDC-RD model leverages reference atmospheric models to estimate and compensate for the tropospheric delay in SAR images. This model effectively mitigates the impact of tropospheric delay in SAR geolocation. To further optimize the TDC-RD model solution, a digital elevation model (DEM)-assisted dual iteration method is proposed. This method iteratively adjusts the target's plane position and elevation in an alternating manner. The effectiveness of the TDC-RD model has been validated through both simulation experiments and actual flight experiments. The results show a significant improvement in geolocation accuracy compared to existing methods, with a maximum reduction of 11.39 m and 24.33% in the mean absolute error (MAE) of SAR geolocation. The TDC-RD model has a great advantage in long-range SAR geolocation. Our research enhances the accuracy and stability of high-altitude airborne SAR geolocation without requiring ground control points. © 2025 IEEE.

关键词： Troposphere

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