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Development of an Online Fault-Diagnostic-System Based on STM32 for Actuators 12

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Development of an Online Fault-Diagnostic-System Based on ST...

12th IEEE Global Reliability and Prognostics and Health Management, PHM-Nanjing 2021

作者： Chen, Shaowei Huang, Yanping Liu, Hengyu Wen, Pengfei Yang, Ning Zhao, Shuai School Of Electronics And Information Northwestern Polytechnical University Xi'an710129 China Department Of Energy Technology Aalborg University Aalborg9220 Denmark National Key Laboratory of Science and Technology on Integrated Technology Control Flight Automatic Control Research Institute A Vic Xi'an710065 China No. 365 Research Institute Of Northwestern Polytechnical University Xi'an710065 China

ISBN: (纸本)9781665401302

In the process of fault diagnosis for complicated mechatronic equipment such as actuators, the fault diagnosis method is usually calculated on the equipment side. When computing devices are not easy to be installed at the object end, the embedded device can be used for real-time diagnosis, so as to meet the requirement of no network, low bandwidth, low power consumption, and low delay, at the same time improve the availability of the fault diagnosis device. While ensuring the recognition rate and the diagnosis effect, the security, and portability of the equipment are improved. In this paper, an online fault diagnosis system for mechatronic actuators based on the STM32 embedded platform is developed. This system uses a backpropagation neural network and a support vector machine fusion model to diagnose the actuator faults and reduces the memory usage by compressing the model, discretizing the attributes, and reducing the number of input features. Real-time data acquisition, feature extraction, fusion fault diagnosis, and data storage are implemented on this embedded system. © 2021 IEEE.

关键词： Failure analysis

Cryogenic Deformation Tailors the Dislocation Accumulation Mode to Modify Grain Boundary Character Distribution of Incoloy 925

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SSRN 2023年

作者： Zhu, Yulong Cao, Yu Ma, Junhao Zhang, Jieke He, Qubo Luo, Rui Jia, Xuhong Liu, Quanyi Xiao, Jun College of Civil Aviation Safety Engineering Civil Aviation Flight University of China Guanghan618307 China College of Materials Science and Engineering Chongqing University Chongqing400044 China Civil Aircraft Fire Science and Safety Engineering Key Laboratory of Sichuan Province China Chongqing Materials Research Institute Co. Ltd Chongqing400707 China School of Materials Science and Engineering Jiangsu University Jiangsu Zhenjiang212013 China State Key Laboratory of Compressor Technology Hefei General Machinery Research Institute Co. Ltd Anhui Hefei230031 China

Cryogenic deformation was introduced in thermomechanical processing to restrict dislocation mobility and tailor the initial dislocation distribution at the deformation stage, subsequently followed by annealing treatment to alter the grain boundary characteristic distribution with a view to the feasibility of grain boundary engineering in Incoloy 925. The microstructural evolution deformed at cryogenic (77K) and room temperature (298K) under various rolling reductions and annealing conditions was systematically studied to optimize the grain boundary network, which is evaluated using multi-source quantitative statistics of the twin related domains. The results showed that cryogenic deformation can adjust the dislocation accumulation mode and plastic deformation mechanism. Geometrically dislocation distributions with fishbone-like, ribbon-like or lamellar distributions can be observed from HR-EBSD-derived geometrically necessary dislocation distribution maps. During the subsequent annealing, the samples with 5% and 15% pre-strain are incapable of producing the ideal twin related domains, while the sample annealed at 1075°C with 10% pre-strain show the optimization of GBCD with the highest Σ3 n (n = 1, 2, and 3) boundary fraction of 69.67%. Compared with room temperature pre-deformation, cryogenic deformation can effectively reduce the critical temperature of GBE, and also leads to the proportion of Σ3 n boundaries increasing from 31.47% to 67.46% in 10%/1050°C sample. Meanwhile, with the appropriate strain, cryogenic deformation is more conducive to optimizing the GBCD than room-temperature deformation. © 2023, The Authors. All rights reserved.

关键词： Room temperature

Characterizing Burning Behaviour of Convection-controlled Pool Fires at Sub-Atmospheric Pressure by Stagnation Theory

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SSRN 2023年

作者： Guo, Youwei Xiao, Guoqing Chen, Jian Xiong, XingYu Deng, Hongbo Liu, Xiang Wang, Lingyuan Li, Yuanyuan College of Chemistry and Chemical Engineering Southwest Petroleum University Sichuan Chengdu610500 China Oil & Gas Fire Protection Key Laboratory of Sichuan Province Sichuan Chengdu611731 China Gas Reservoir Geol & Exploita Sichuan Chengdu610500 China College of Safety Science and Engineering Xi’an University of Science and Technology 710054 China College of Civil Aviation Safety Engineering Civil Aviation Flight University of China Sichuan Deyang618307 China Civil Aircraft Fire Science and Safety Engineering Key Laboratory of Sichuan Province Sichuan Deyang618307 China

Pool fires play a critical role in examining the burning behaviour of diffusion flames and are sensitive to changes in scale and environmental conditions. Understanding the evolution of pool fires under low-pressure conditions, common in plateau or flight scenarios, is essential for both fire safety and energy utilization. This study investigates the effects of pressure on pool fires through a series of small-scale experiments carried out in a pressure chamber that provides stable conditions ranging from 95 kPa to 40 kPa. Pool scales between 7 cm and 16 cm were examined, a range dominated by convective heat transfer. Methanol and heptane were chosen to discern fuel-specific variations in burning behaviour under decreased pressure. The findings demonstrate an increase in the axial flame temperature with reducing pressure, while radiative output exhibits an inverse relationship with pressure. Additionally, convective heat transfer toward surroundings appears to rise with decreasing pressure. A modified stagnation theory solution is proposed to model the mass burning rate of convection-controlled pool fires under low pressure, which shows satisfactory agreement with the experimental data. This research could potentially contribute to the comprehension of pool fires and the safety of energy in sub-atmospheric pressure conditions in the future. © 2023, The Authors. All rights reserved.

关键词： Energy utilization

4-D Trajectory Prediction and Dynamic Planning of Aircraft Taxiing Considering Time and Fuel

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Transactions of Nanjing University of Aeronautics and Astronautics 2021年第5期38卷 852-866页

作者： LI Nan ZHANG Lei SUN Yu GAO Zheng Civil Aviation Flight Wide Area Surveillance and Safety Control Technology Key Laboratory Civil Aviation University of ChinaTianjin 300300P.R.China North China Air Traffic Management Bureau Civil Aviation Administration of ChinaBeijing 100000P.R.China Tianjin Air Traffic Management Bureau Civil Aviation Administration of ChinaTianjin 300300P.R.China

Most of the traditional taxi path planning studies assume that the aircraft is in uniform speed,and the optimization goal is the shortest taxi *** it is easy to solve,it does not consider the changes in the speed profile of the aircraft when turning,and the shortest taxi time does not necessarily bring the best taxi fuel *** this paper,the number of turns is considered,and the improved A*algorithm is used to obtain the P static paths with the shortest sum of the straight-line distance and the turning distance of the aircraft as the feasible taxi *** balancing taxi time and fuel consumption,a set of Pareto optimal speed profiles are generated for each preselected path to predict the 4-D trajectory of the *** on the 4-D trajectory prediction results,the conflict by the occupied time window in the taxiing area is *** the conflict aircraft,based on the priority comparison,the waiting or changing path is selected to solve the taxiing ***,the conflict free aircraft taxiing path is generated and the area occupation time window on the path is *** experimental results show that the total taxi distance and turn time of the aircraft are reduced,and the fuel consumption is *** proposed method has high practical application value and is expected to be applied in real-time air traffic control decision-making in the future.

关键词： air transportation trajectory planning heuristic algorithm taxi time taxi fuel consumption

A Global to Local Double Embedding Method for Multi-person Pose Estimation 15th

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A Global to Local Double Embedding Method for Multi-person P...

15th Asian Conference on Computer Vision, ACCV 2020

作者： Xu, Yiming Li, Jiaxin Ding, Yan Wei, Hua-Liang Yingcai Honors College University of Electronic Science and Technology of China Chengdu China Key Laboratory of Dynamics and Control of Flight Vehicle Ministry of Education School of Aerospace Engineering Beijing Institute of Technology Beijing100081 China Department of Automatic Control and Systems Engineering University of Sheffield SheffieldS1 3JD United Kingdom

ISBN: (纸本)9783030695408

Multi-person pose estimation is a fundamental and challenging problem to many computer vision tasks. Most existing methods can be broadly categorized into two classes: top-down and bottom-up methods. Both of the two types of methods involve two stages, namely, person detection and joints detection. Conventionally, the two stages are implemented separately without considering their interactions between them, and this may inevitably cause some issue intrinsically. In this paper, we present a novel method to simplify the pipeline by implementing person detection and joints detection simultaneously. We propose a Double Embedding (DE) method to complete the multi-person pose estimation task in a global-to-local way. DE consists of Global Embedding (GE) and Local Embedding (LE). GE encodes different person instances and processes information covering the whole image and LE encodes the local limbs information. GE functions for the person detection in top-down strategy while LE connects the rest joints sequentially which functions for joint grouping and information processing in A bottom-up strategy. Based on LE, we design the Mutual Refine Machine (MRM) to reduce the prediction difficulty in complex scenarios. MRM can effectively realize the information communicating between keypoints and further improve the accuracy. We achieve the competitive results on benchmarks MSCOCO, MPII and CrowdPose, demonstrating the effectiveness and generalization ability of our method. © 2021, Springer Nature Switzerland AG.

关键词： Embeddings

Doppler Tracking Data of Martian Mission Tianwen-I and Upper Limit of Stochastic Gravitational Wave Background

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arXiv

arXiv 2024年

作者： Bi, Xiaoming Guo, Zhongkai Zou, Xiaobo Huang, Yong Li, Peijia Cao, Jianfeng Chen, Lue Tang, Wenlin Lau, Yun Kau School of Physical Science and Technology Lanzhou University Lanzhou730000 China Beijing Institute of Space Mechanics and Electricity China Academy of Space Technology Beijing100094 China Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai200030 China Key Laboratory of Planetary Sciences Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai200030 China Key Laboratory of Electronics and Information Technology for Space System National Space Science Center Chinese Academy of Sciences Beijing100190 China Science and Technology on Aerospace Flight Dynamics Laboratory Beijing Aerospace Control Center Beijing China Institute of Applied Mathematics Morningside Center of Mathematics LSSC Academy of Mathematics and System Science Chinese Academy of Sciences 55 Zhongguancun Donglu Beijing100190 China

Two way ranging data for spacecraft tracking of China’s first Martian mission Tianwen-I is analysed. Shortly before the spacecraft entered the Mars parking orbit, the two way coherent microwave link between the spacecraft and the Earth resembles a long arm gravitational wave interferometer, with both the spacecraft and the Earth regarded as in an approximate free falling state. By carefully selecting and analysing data segments of the time series of the two way ranging data during this time span, a parametric statistical model is built for the data segments and an upper limit for the stochastic gravitational waves background (SGWB) is then estimated within the frequency window 0.1Hz to 0.1 mHz. The upper bound improves considerably on those obtained before. In particular, around the deci-Hz band, there is a three orders improvement on the bound obtained previously by the two way ranging data of the Chang e 3 mission. Scientific applications of the upper bound is then considered and a weak upper bound is worked out for axions which is a promising candidate for ultra light dark matter. Copyright © 2024, The Authors. All rights reserved.

关键词： Spacecraft

Study on modal characteristics and vibration reduction of an aircraft rotor–stator brake-induced squeal system

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Acta Mechanica Sinica 2020年第6期36卷 1350-1359,I0004页

作者： Qiaozhi Yin Xiaohui Wei Hong Nie Jian Deng State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and AstronauticsNanjing210016China Key Laboratory of Fundamental Science for National Defense-Advanced Design Technology of Flight Vehicle Nanjing University of Aeronautics and AstronauticsNanjing210016China Nanjing Center for Multifunctional Lightweight Materials and Structures Nanjing University of Aeronautics and AstronauticsNanjing210016China

Based on the modal coupling theory,the rotor and stator contact stiffness and axial relative velocity are considered to build an electric aircraft brake dynamic system model in this *** the complex modal analysis and transient dynamic analysis methods are used to study the aircraft brake squeal performance and vibratory *** unstable vibration modes indicate that the out-of-plane vibration plays an important role and the feed-in energy is larger than the output energy in the brake rotor–stator module so that brake squeal takes *** the influences of the contact stiffness,friction damping and frictional coefficient on the brake squeal system are carried out,laying the foundation for the three proposed vibration suppression *** show that the coefficient negative-slope condition will intensify the ***,a linear relationship between the squeal factor and the frictional coefficient is obtained to provide a guidance to predict squeal stability under more *** reduction design shows that adding a damping layer to the brake mechanism and chamfering the edge of braking stators both can reduce brake squeal effectively,while slotting braking stators is invalid in aircraft braking system.

关键词： Aircraft rotor-stator bake-induced vibration Brake squeal-Vibration stability Modal coupling Vibration suppression

3 Nm-Sized Porous Graphene-Based Anion Exchange Membranes for Efficient and Stable Water Electrolysis

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SSRN 2024年

作者： Liu, Xiang Zhang, Ai ling Yu, Hao Chen, Liang Zhang, Lei Zhao, Yong Li, Jialu Zhang, Weiqi Zhou, Zhiting Zhou, Yongyan Wang, Yuanyuan Ou, Jian Zhen Civil Aircraft Fire Science and Safety Engineering Key Laboratory of Sichuan Province Guanghan618307 China College of Civil Aviation Safety Engineering Civil Aviation Flight University of China School of Science Sichuan Guanghan618307 China Xihua University Jinzhou Road Sichuan Chengdu610039 China Sichuan Key Technology Engineering Research Center for All-electric Navigable Aircraft Sichuan Guanghan618307 China Key Laboratory of Advanced Technologies of Materials Ministry of Education School of Materials Science and Engineering Southwest Jiaotong University Chengdu610031 China School of Engineering RMIT University MelbourneVIC3000 Australia The 7th Oil Production Plant of Changqing Oilfield Gansu Qingyang745708 China

Alkaline water electrolysis is one of the primary drivers of hydrogen energy development, and anion exchange membranes (AEMs) play a dual role in ensuring both conductivity and safety. However, traditional polymer AEMs have a wide pore size distribution and poor chemical stability, making it difficult to achieve a long-term balance between conductivity and safety of the water electrolysis system. Here, we select inorganic two-dimensional multilayer graphene oxide (GO) membranes as AEMs, using carboxylated wrinkled graphene (WG) and ethylenediamine (EDA) to create a cation-modified porous EDA-GO/WG (E-W/G) composite membrane with a 3 nm pore size. The enlarged channel size and enhanced hydrophilicity improve OH- permeability compared to the pristine GO membrane, while the strengthened hydration layer acts as a barrier to hydrophobic gases for O2/H2 separation. The results show that the prepared E-W/G membrane exhibits superior current density (600 mA cm-2) and gas impermeability (gas purity 99.99%) compared to the commercial Fumasep FAA-3-50 membrane (590 mA cm-2 and 99.81%, respectively). Furthermore, after continuous testing for 168 hours in high-temperature and alkaline environments, the E-W/G membrane maintained conductivity comparable to its initial state and showed enhanced gas impermeability. Our strategy provides new insights into the design of high-performance AEMs and is expected to contribute to the advancement of the hydrogen energy industry. © 2024, The Authors. All rights reserved.

关键词： Graphene

Sub-Nano Porous Graphene-Based Membranes Enabled by In-Situ-Grown Zif-8 for Enhanced CO2 Capture

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SSRN 2024年

作者： Zhang, Lei Zhao, Yong Yu, Hao Chen, Liang Liu, Xiang Zhang, Ailing Ou, Jian Zhen Civil Aircraft Fire Science and Safety Engineering Key Laboratory of Sichuan Province Guanghan618307 China College of Civil Aviation Safety Engineering Civil Aviation Flight University of China School of Science Sichuan Guanghan618307 China Xihua University Jinzhou Road Sichuan Chengdu610039 China Sichuan Key Technology Engineering Research Center for All-electric Navigable Aircraft Sichuan Guanghan618307 China Key Laboratory of Advanced Technologies of Materials Ministry of Education School of Materials Science and Engineering Southwest Jiaotong University Chengdu610031 China School of Engineering RMIT University MelbourneVIC3000 Australia The 7th Oil Production Plant of Changqing Oilfield Gansu Qingyang745708 China

Graphene oxide (GO) membranes hold promise for selective CO2 adsorption over N2 due to their carboxyl groups, making them attractive for flue gas CO2 capture. However, challenges such as limited carboxyl content, flexible nanosheets, and dense layer stacking hinder their N2/CO2 gas selectivity, pressure resistance, and permeability. In this study, we introduce a specific sub-nanometer framework structure within GO membranes by in-situ growing ZIF-8 nanocrystals. This novel approach, achieved through simultaneous infiltration of zinc nitrate and 2-methylimidazole precursors on both sides of the membrane, enhances CO2 capture and pressure resistance capabilities of resulting ZIF-8@GO composite membranes. Additionally, the incorporation of carboxylated wrinkled graphene (WG) and ethylenediamine (EDA) cross-linking agent molecules improves CO2 capture capability and introduces reinforced porous structures to enhance permeability. Experimental results demonstrate remarkable permeability, selectivity, and pressure resistance of the prepared ZIF-8@EDA-WG/GO composite membranes. Under a gas pressure of 0.2 MPa, permeability reaches 1850 GPU, with theoretical selectivity for N2/CO2 single gas and separation factors for mixed gases of 19 and 32.3, respectively, surpassing conventional GO membranes (200 GPU, 1.4, and 2.1). Even under elevated air pressure conditions (1.2 MPa), the composite membranes maintain a theoretical selectivity of 13.4. Our CO2 capture membrane design strategy not only advances the development of functional membranes but also contributes to mitigating CO2 emissions from flue gas, thereby combating global warming. © 2024, The Authors. All rights reserved.

关键词： Graphene