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Research on fault diagnosis of planetary gearbox based on Variable Multi-Scale Morphological Filtering and improved Symbol Dynamic Entropy

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Research Square

Research Square 2021年

作者： Liu, Tongtong Cui, Lingli Zhang, Jianyu Zhang, Chao Key Laboratory of Advanced Manufacturing Technology Beijing University of Technology Chao Yang District Beijing100124 China Inner Mongolia Key Laboratory of Intelligent Diagnosis and Control of Mechatronic Systems Inner Mongolia University of Science and Technology Baotou014010 China

Under complex working conditions with noise interference, the fault feature of planetary gearbox is difficult to be extracted and the fault mode is difficult to be identified. To tackle this problem, the technologies of Variable Multi-scale Morphological Filtering (VMSMF) and Average Multi-scale Double Symbolic Dynamic Entropy (AMDSDE) are proposed in this paper. VMSMF selects Chebyshev Window as the structural element and automatically selects the optimal scale parameters according to the signal characteristics of the planetary gearbox, which improves the filtering accuracy and calculation efficiency. AMDSDE fully considers the correlation between various state modes. Once combined with relevant knowledge of Mathematical statistics, the algorithm can effectively reduce misjudgment. Firstly, the Turn Domain Resampling (TDR) is used to transform the time domain signal of variable speed into the angle domain signal that is not affected by speed change. Secondly, the proposed VMSMF is used to de-noise the vibration signal, and the fault signal with a high signal-to-noise ratio is obtained. Finally, AMDSDE is used to extract the entropy value of the fault signal and judge the fault type. The proposed technology is verified by four kinds of signals collected from the sun gear of the planetary gearbox under non-stationary working conditions. © 2021, CC BY.

关键词： Pattern recognition

Study on Mechanical Properties of Dual-Channel Cryogenic 3d Printing Scaffold for Mandibular Defect Repair

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SSRN 2023年

作者： Gao, Lilan Sun, Mengchao Liu, Jie Meng, Lulu Liu, Han Zheng, Xiongfei Liu, Hao Li, Ruixin Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300382 China Tianjin300382 China Beijing Friendship Hospital Capital Medical University 100050 China State Key Laboratory of Robotics Institutes for Robotics and Intelligent Manufacturing Shenyang Institute of Automation Chinese Academy of Sciences Shenyang110017 China Tianjin Key Laboratory of Oral and Maxillofacial Function Reconstruction Tianjin Stomatological Hospital The Affiliated Stomatological Hospital of Nankai University Tianjin300041 China

Mandibular defect repair has always been a clinical challenge, facing technical bottleneck. The new materials directly affect technological breakthroughs in mandibular defect repair field. Our aim is to fabricate a scaffold for mandibular defect repairing with advanced biomaterials. Therefore, a novel dual-channel printed scaffold consisting of silk fibroin/collagen type I /hydroxyapatite (SCH) and polycaprolactone/hydroxyapatite (PCL/HA) was fabricated by 3D printing technology with double nozzles. The mechanical properties and behaviors of dual-channel printed scaffold were investigated by performing uniaxial compression, creep, stress relaxation and ratcheting experiments respectively. The experiments indicated the Young modulus of dual-channel printed scaffold was 60.1 kPa and dual-channel printed scaffold was typical nolinear viscoelastic consistent with bone tissue. Finite Element Analysis (FEA) was employed performing a numerical simulation to evaluate the implantation effect in mandible. The stress distribution of the contact area between scaffold and defect was uniform, the maximum Mises stress of cortical bone and cancellous bone in defect area were 54.52MPa and 3.196MPa, and the maximum displacement of cortical bone and cancellous bone in defect area were 0.1575mm and 0.1555mm, which were distributed in the incisor region. The peak value of the maximum Mises stress for the scaffold implanted was 3.128× MPa and the maximum displacement was 6.453×mm distributed near incisor area. The displacement distribution of the scaffold was consistent with that of cortical and cancellous bone. The scaffold recovered well when the force applied on it disappeared. Above all, dual-channel printed scaffold had excellent bio-mechanical properties in implanting mandible, which provides a new idea for the reconstruction of irregular bone defects in the mandible and has good clinical development prospects. © 2023, The Authors. All rights reserved.

关键词： 3D printing

A New Combined Heat Source Model of Hollow-Cathode Nanosecond Pulsed Electron Beam for Material Irradiation

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SSRN 2023年

作者： He, Weiguo Huo, Weijie Duan, Xinxin Zhu, Kangwu Wang, Feng School of Mechatronic Engineering and Automation Shanghai University Shanghai200444 China School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced Study University of Chinese Academy of Sciences Hangzhou310024 China Key Laboratory of Gravitational Wave Precision Measurement of Zhejiang Province Taiji Laboratory for Gravitational Wave Universe Hangzhou310024 China Shanghai Aerospace Electronic Technology Institute Shanghai201109 China Shanghai Aerospace Control Technology Institute Shanghai201109 China

The hollow-cathode nanosecond pulsed electron beam changes the components and organization of the material surface through thermal coupling and prepares a modified layer on the surface of the base material with greatly optimized physicochemical and mechanical properties, which has a wide range of applications. In this study, in view of the insufficient research on the heat source model in the hollow-cathode nanosecond pulsed electron beam, a combined heat source model is proposed for the first time by abstracting the action of the hollow-cathode electron beam and the material as two sets of Gaussian heat sources with different parameters, and by equating the heat source of the action of the high-energy electron beam with the body heat source, and the action of the irradiation of the electron beam during the on-state phase with the surface heat source, respectively. Besides, the influence of heat source parameters on the temperature distribution is analyzed. The results show that for the nanosecond pulsed intense current electron beam-material interaction process, the use of a multi-parameter heat source model describes it more accurately compared to the average energy density values. At the same time, in order to further verify the accuracy of the model, a validation experiment was carried out using the titanium alloy Ti-6Al-4V material, and the experimental results show that the formation of irradiation morphology can be more accurately described using the combined heat source model with different storage energies, and the experimental results also show that uniform irradiation effect in a certain area can be realized by reasonably choosing the parameters of the energy storage capacitor. © 2023, The Authors. All rights reserved.

关键词： Electron beams

Two points are enough

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arXiv

arXiv 2024年

作者： Liu, Hao Zhao, Yanbin Zheng, Huarong Fan, Xiulin Deng, Zhihua Chen, Mengchi Wang, Xingkai Liu, Zhiyang Lu, Jianguo Chen, Jian State Key Laboratory of Fluid Power Components and Mechatronic Systems School of Mechanical Engineering Zhejiang University Hangzhou China Ocean College Zhejiang University Hangzhou China State Key Laboratory of Silicon and Advanced Semiconductor Materials School of Materials Science and Engineering Zhejiang University Hangzhou China Nanyang Technological University Singapore School of Control Science and Engineering Zhejiang University Hangzhou China School of Materials Science and Engineering Tianjin University Tianjin China School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen China

Prognosis and diagnosis play an important role in accelerating the development of lithium-ion batteries, as well as reliable and long-life operation. In this work, we answer an important question: What is the minimum amount of data required to extract features for accurate battery prognosis and diagnosis? Based on the first principle, we successfully extracted the best two-point feature (BTPF) for accurate battery prognosis and diagnosis using the fewest data points (only two) and the simplest feature selection method (Pearson correlation coefficient). The BTPF extraction method is tested on 820 cells from 6 open-source datasets (covering five different chemistry types, seven manufacturers, and three data types). It achieves comparable accuracy to state-of-the-art features in both prognosis and diagnosis tasks. This work challenges the cognition of existing studies on the difficulty of battery prognosis and diagnosis tasks, subverts the fixed pattern of establishing prognosis and diagnosis methods for complex dynamic systems through deliberate feature engineering, highlights the promise of data-driven methods for field battery prognosis and diagnosis applications, and provides a new benchmark for future studies. Copyright © 2024, The Authors. All rights reserved.

关键词： Lithium-ion batteries

Adaptive Fault Tolerant Tracking control of Heterogeneous Multi-Agent Systems with Non-Cooperative Target

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SSRN 2022年

作者： Dong, Lijing Liu, Kaige Du, Shengli Yan, Hao Shen, Haikuo School of Mechanical Electronic and Control Engineering Beijing Jiaotong University Beijing100044 China Key Laboratory of Vehicle Advanced Manufacturing Measuring and Control Technology Beijing Jiaotong University Ministry of Education Beijing100044 China College of Automation Faculty of Information Technology Beijing University of Technology Beijing100124 China Engineering Research Center of Intelligent Perception and Autonomous Control Ministry of Education Beijing100124 China

In this paper, the fault tolerant tracking control problem of heterogeneous multi-agent systems(MASs) is studied, in which a non-cooperative target is considered. Since the target is non-cooperative, the system matrix of the target is unavailable. Therefore, the existing results dealing with consensus problem of heterogeneous multi-agent based on known exosystem matrix are inapplicable here. A neural-network-based adaptive observer is designed for estimating the output of the non-cooperative target. Then, a finite-time adaptive fault tolerant controller is developed to resolve the heterogeneous target tracking problem with actuator failures, with which the tracking errors converge within finite time. The proposed controller is fully distributed, which no longer requires the system matrix of the target and actuator fault rates of the tracking agents. Finally, the effectiveness of the developed strategies and the correctness of achieved stability conditions are verified by some numerical examples. © 2022, The Authors. All rights reserved.

关键词： Target tracking

Spectrum broadening suppression for kW-class narrow linewidth FBG-based fiber laser

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Spectrum broadening suppression for kW-class narrow linewidt...

Conference on Lasers and Electro-Optics (CLEO)

作者： Yulun Wu Yusheng Huang Zehui Wang Dan Li Ping Yan Qirong Xiao Mali Gong State Key Laboratory of Precision Measurement Technology and Instruments & Key Laboratory of Photonics Control Technology of the Ministry of Education Tsinghua University Beijing China Research Laboratory for Biomedical Optics and Molecular imaging Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences Shenzhen China Research Laboratory for Biomedical Optics and Molecular Imaging Shenzhen Key Laboratory for Molecular Imaging Guangdong Provincial Key Laboratory of Biomedical Optical Imaging Technology CAS Key Laboratory of Health Informatics Shenzhen Institutes of Advanced Technology Shenzhen China

Spectral broadening caused by nonlinear effects was analyzed in the narrow linewidth FBG-based fiber laser. Kilowatt-class narrow linewidth fiber lasers were established. The maximum power and power spectral density w... 详细信息

ISBN: (纸本)9781943580910

关键词： Laser theory Lasers and electrooptics Laser excitation Electrooptical waveguides Pump lasers Fiber lasers

Study of Nanosecond Pulsed Hollow-Cathode Electron Beam Generation and Transportation Based on Pic-Mcc Simulation

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SSRN 2023年

作者： Huo, Weijie He, Weiguo Han, Luofeng Zhu, Kangwu Wang, Feng Shanghai Aerospace Electronic Technology Institute Shanghai201109 China School of Mechatronic Engineering and Automation Shanghai University Shanghai200444 China School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced Study University of Chinese Academy of Sciences Hangzhou310024 China Key Laboratory of Gravitational Wave Precision Measurement of Zhejiang Province Taiji Laboratory for Gravitational Wave Universe Hangzhou310024 China Shanghai Aerospace Control Technology Institute Shanghai201109 China

This work employs the PIC-MCC method to study the nanosecond pulsed hollow-cathode discharge and electron beam generation process. The electron beam’s energy and current distribution characteristics at the anode exit are investigated, and the simulation’s grid and step sizes are set as 0.04 μm and 5*10-13 s, respectively. Experimental parameters are used in the simulation, and experimental results are also used to verify the simulation accuracy. The simulations investigate the transportation characteristics of the electron beam under different energies and currents and obtain the effects of voltage, current, and ion density on the distribution characteristics of the electron beam. The electron beam current generated by the hollow-cathode discharge is gradually transformed from a random distribution in the central region to a Gaussian distribution. Due to the ion channel caused by the action of runaway electron pre-ionization, the high-energy electron beam achieves focused transport over a certain distance, and the high-energy electron beam has a smaller Gaussian radius than the source input. Besides, the ion-focusing channel formed by the high-energy electron transportation process can realize the transportation of the high-current electron beam in the conduction stage. © 2023, The Authors. All rights reserved.

关键词： Electron beams

Effects of strain paths on the fracture forming limit of high strength structural steel sheets

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Effects of strain paths on the fracture forming limit of hig...

2020 International Conference on Internet of Things, Artificial Intelligence and Mechanical Automation, IoTAIMA 2020

作者： Xu, Teng Xia, Qin-Xiang Qi, Zhen-Jie Wu, Xiao-Yu Ran, Jia-Qi Gong, Feng Guangdong Provincial Key Laboratory of Micro Nano Optomechatronics Engineering College of Mechatronics and Control Engineering Shenzhen University China Guangdong Provincial Key Laboratory of Precision Equipment and Manufacturing Technology School of Mechanical and Automotive Engineering South China University of Technology China Shenzhen Key Laboratory of Advanced Manufacturing Technology for MouldandDie College of Mechatronics and Control Engineering Shenzhen University China National Engineering Research Center of Near-Net-Shape Forming for Metallic Materials China

The cruciform two-axial tensile specimen was designed and the two-axial tensile test scheme for different strain paths was developed. The effect of strain paths on the forming limit of high strength structural steel plates was obtained by the DIC method. The results show that for the unidirectional alternating loading test scheme, the equivalent strain of the ultimate strain is less than the sum of the equivalent strains from each step. When the main strain direction of the specimen pre-strain is perpendicular to the final strain path, the forming limit decreases with the increase of the pre-strain. © 2020 Published under licence by IOP Publishing Ltd.

关键词： Strain

Dynamic Gesture Recognition Algorithm Based on 3D Convolutional Neural Network

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Computational Intelligence and Neuroscience 2021年 2021卷 4828102页

作者： Liu, Yuting Jiang, Du Duan, Haojie Sun, Ying Li, Gongfa Tao, Bo Yun, Juntong Liu, Ying Chen, Baojia Key Laboratory of Metallurgical Equipment and Control Technology of Ministry of Education Wuhan University of Science and Technology Wuhan430081 China Research Center for Biomimetic Robot and Intelligent Measurement and Control Wuhan University of Science and Technology Wuhan430081 China Hubei Key Laboratory of Mechanical Transmission and Manufacturing Engineering Wuhan University of Science and Technology Wuhan430081 China Hubei Key Laboratory of Hydroelectric Machinery Design and Maintenance China Three Gorges University Yichang443002 China

Gesture recognition is one of the important ways of human-computer interaction, which is mainly detected by visual technology. The temporal and spatial features are extracted by convolution of the video containing gesture. However, compared with the convolution calculation of a single image, multiframe image of dynamic gestures has more computation, more complex feature extraction, and more network parameters, which affects the recognition efficiency and real-time performance of the model. To solve above problems, a dynamic gesture recognition model based on CBAM-C3D is proposed. key frame extraction technology, multimodal joint training, and network optimization with BN layer are used for making the network performance better. The experiments show that the recognition accuracy of the proposed 3D convolutional neural network combined with attention mechanism reaches 72.4% on EgoGesture dataset, which is improved greatly compared with the current main dynamic gesture recognition methods, and the effectiveness of the proposed algorithm is verified. © 2021 Yuting Liu et al.

关键词： Convolution