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Hole surface strengthening mechanism and riveting fatigue life of CFRP/aluminum stacks in robotic rotary ultrasonic drilling

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Chinese Journal of Aeronautics 2023年第10期36卷 471-484页

作者： Song DONG Wenhe LIAO kan zheng Feng XUE Lianjun SUN School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094China

Carbon fiber reinforced plastic(CFRP)and aluminum stacks are widely used in aviation industry due to light weight and high performance.Millions of rivet holes need to be drilled on body materials,and more than 80%of fatigue cracks occur at the connection holes,so the damage and residual stress of hole surface have crucial effect on the riveting fatigue life of CFRP/aluminum stacks and the flight performance.Recently,robotic rotary ultrasonic drilling(RRUD)technology is a promising method to machine the stacks.However,the hole surface strengthening mechanism in RRUD and the service performance of the riveting joint are not verified.Thus,in this paper,the hole surface strengthening mechanism of RRUD for CFRP/aluminum stacks is investigated,a theoretical residual stress model is established,and the fatigue life experiment of riveted joints is conducted.Firstly,analysis on residual stress in RRUD is carried out with consideration of strengthening force and cutting temperature.Residual stress model is established based on the calculation of elastic stress,plastic stress and stress release.Validation experiment results show that ultrasonic vibration changes residual stress from tensile stress to compressive stress.At the same time,comparative damage analysis of CFRP hole exit and hole surface in robotic conventional drilling(RCD)and RRUD is presented.Finally,fatigue strength experiments of riveted joints are conducted for performance verification.Experimental results indicate that fatigue life of single-hole riveted joints is increased by 68%with ultrasonic vibration,and four-hole riveted joint arranged according to aerospace design standards is increased by more than 86%.

关键词： CFRP/aluminum stacks Drilling damage Residual stress Riveting fatigue life Robotic rotary ultrasonic drilling

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Stability analysis of robotic longitudinal-torsional composite ultrasonic milling

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Chinese Journal of Aeronautics 2022年第8期35卷 249-264页

作者： Lianjun SUN Wenhe LIAO kan zheng Wei TIAN Jinshan LIU Jindan FENG School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094China College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China China Academy of Space Technology Beijing 100094China

Currently,industrial robots are considered as an alternative towards traditional machine tools.Especially for the large-scale parts milling,robotic flexibility and low cost make it possess the irreplaceability.However,the milling chatter caused by its weak rigidity hampers robotic application and promotion severely in aviation industry.Rotary ultrasonic milling(RUM)technology with one-dimensional axial vibration has been proven and approved on avoiding robotic chatter.Based on this,the research of project team demonstrates that longitudinal-torsional composite ultrasonic milling(CUM-LT)involving separation characteristic has a greater advantage than RUM in terms of chatter suppression.Thereby,the CUM-LT as a new means is applied to avoid processing vibration of robotic milling system.And its influence mechanism on stability improvement of weak stiffness processing system is clarified.Meanwhile,the approaches to strengthen separation effect are provided innovatively.Moreover,a new analysis method of robotic CUM-LT(RCUM-LT)stability is proposed on the basis of ultrasonic function angles.The simulation and experimental results indicate that compared with robotic RUM(RRUM),stability regions of separated RCUM-LT(SRCUM-LT)and unseparated RCUM-LT(URCUM-LT)are improved by 124.42%and39.20%,respectively.The addition of torsional ultrasonic energy has a wonderful effect on the milling chatter suppression of low stiffness robots.

关键词： Chatter suppression Industrial robots Longitudinal-torsional composite Rotary ultrasonic milling Stability analysis

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Chatter stability of robotic rotary ultrasonic countersinking

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Chinese Journal of Aeronautics 2023年第10期36卷 434-444页

作者： Zhenwen SUN Wenhe LIAO kan zheng Song DONG Pei LEI Lianjun SUN School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094China Chengdu Aircraft Industrial(Group)Co. Ltd.Chengdu 610091China

In recent years,industrial robots have received extensive attention in manufacturing field due to their high flexibility and great workspace.However,the weak stiffness of industrial robots makes it extremely easy to arouse chatter,which affects machining quality inevitably and generates noise pollution in severe cases.Compared with drilling,the chatter mechanism of robotic countersinking is more complex.The external excitation changes with cutting width and depth in countersinking.This characteristic results in time-varying and nonlinearity of robotic countersinking dynamics.Thus,it is urgent to propose a new method of chatter suppression and provide an accurate stability analysis model.As a new special machining technology,rotary ultrasonic machining has been proved to improve robotic drilling and milling stability effectively.Based on this,robotic rotary ultrasonic countersinking(RRUC)is proposed to improve the robotic countersinking stability in this paper.A three-dimensional stability domain method of RRUC is established.First,the countersinking process was divided intoρparts.The dynamic model of every unit was constructed based on ultrasonic function angle(γ)and dynamic chip area.Then,the stability region of RRUC is obtained based on the semi-discrete method(SDM).Compared with the robotic conventional countersinking(RCC),RRUC improves the stability by 27%.Finally,the correctness and effectiveness of the stability region model are proved by robotic ultrasonic countersinking experiments.

关键词： Industrial robot Rotary ultrasonic machining Dynamic model Countersinking chatter Stability analysis

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An intelligent self-sustained RAN slicing framework for diverse service provisioning in 5G-beyond and 6G networks

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Intelligent and Converged Networks 2020年第3期1卷 281-294页

作者： Jie Mei Xianbin Wang kan zheng Electrical and Computer Engineering Western UniversityLondonON N6A 5B9Canada Intelligent Computing and Communication(IC2)Lab Wireless Signal Processing and Network(WSPN)LabKey Laboratory of Universal Wireless CommunicationMinistry of EducationBeijing University of Posts and Telecommunications(BUPT)Beijing 100876China

Network slicing is a key technology to support the concurrent provisioning of heterogeneous Quality of Service(QoS)in the 5th Generation(5G)-beyond and the 6th Generation(6G)networks.However,effective slicing of Radio Access Network(RAN)is very challenging due to the diverse QoS requirements and dynamic conditions in the 6G networks.In this paper,we propose a self-sustained RAN slicing framework,which integrates the self-management of network resources with multiple granularities,the self-optimization of slicing control performance,and self-learning together to achieve an adaptive control strategy under unforeseen network conditions.The proposed RAN slicing framework is hierarchically structured,which decomposes the RAN slicing control into three levels,i.e.,network-level slicing,next generation NodeB(gNodeB)-level slicing,and packet scheduling level slicing.At the network level,network resources are assigned to each gNodeB at a large timescale with coarse resource granularity.At the gNodeB-level,each gNodeB adjusts the configuration of each slice in the cell at the large timescale.At the packet scheduling level,each gNodeB allocates radio resource allocation among users in each network slice at a small timescale.Furthermore,we utilize the transfer learning approach to enable the transition from a model-based control to an autonomic and self-learning RAN slicing control.With the proposed RAN slicing framework,the QoS performance of emerging services is expected to be dramatically enhanced.

关键词： Radio Access Network(RAN) network slicing network resource management intelligent network

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基于VAE-DRSN的微纳卫星推力器故障诊断方法

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航天器工程 2024年第2期33卷 76-83页

作者：朱劲锟郑侃梁振华唐嘉程南京理工大学机械工程学院南京210094

针对微纳卫星推力器故障诊断问题,提出了一种基于变分自编码器-深度残差收缩网络(VAE-DRSN)的数据驱动推进系统故障诊断方法。该方法采用变分自编码器对姿态数据与控制器输出进行特征提取,通过深度残差收缩神经网络对提取的特征进行特... 详细信息

针对微纳卫星推力器故障诊断问题,提出了一种基于变分自编码器-深度残差收缩网络(VAE-DRSN)的数据驱动推进系统故障诊断方法。该方法采用变分自编码器对姿态数据与控制器输出进行特征提取,通过深度残差收缩神经网络对提取的特征进行特征分类,可以高精度地在线检测、诊断和定位推力器的卡开、卡关及效率降低故障,无需卫星推力器模型及动力学模型,且无需单独配备硬件测量机构。经数值仿真验证,结果表明:该方法对于单喷口故障检测正确率可达99%以上,具有良好推力器故障定位及诊断能力。

关键词：微纳卫星故障诊断深度学习变分自编码器推力器故障

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Design and experiment of visual navigated UGV for orchard based on Hough matrix and RANSAC

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International Journal of Agricultural and Biological Engineering 2021年第6期14卷 176-184页

作者： Mingkuan Zhou Junfang Xia Fang Yang kan zheng Mengjie Hu Dong Li Shuai Zhang College of Engineering Huazhong Agricultural UniversityWuhan 430070China Key Laboratory of Agricultural Equipment in Mid-Lower Yangtze River Ministry of Agriculture and Rural AffairsWuhan 430070China

The objective of this study was to develop a visual navigation system capable of navigating an unmanned ground vehicle(UGV)travelling between tree rows in the outdoor orchard.Thus far,while most research has developed algorithms that deal with ground structures in the orchard,this study focused on the background of canopy plus sky to eliminate the interference factors such as inconsistent lighting,shadows,and color similarities in features.Aiming at the problem that the traditional Hough transform and the least square method are difficult to be applied under outdoor conditions,an algorithm combining Hough matrix and random sample consensus(RANSAC)was proposed to extract the navigation path.In the image segmentation stage,this study used an H-component that was adopted to extract the target path of the canopy plus sky.Then,after denoising and smoothing the image by morphological operation,line scanning was used to determine the midpoint of the target path.For navigation path extraction,this study extracted the feature points through Hough matrix to eliminate the redundant points,and RANSAC was used to reduce the impact of the noise points caused by different canopy shapes and fit the navigation path.The path acquisition experiment proved that the accuracy of Hough matrix and RANSAC method was 90.36%-96.81%and the time consumption of the program was within 0.55 s under different sunlight intensities.This method was superior to the traditional Hough transform in real-time and accuracy,and had higher accuracy,slightly worse real-time compared with the least square method.Furthermore,the OPENMV was used to capture the ground information of the orchard.The experiment proved that the recognition rate of OPENMV for identifying turning information was 100%,and the program running time was 0.17-0.19 s.Field experiments showed that the UGV could autonomously navigate the rows with a maximum lateral error of 0.118 m and realize the automatic turning of the UGV.The algorithm satisfied the practical operation requirements of a

关键词： orchard visual navigation unmanned ground vehicle Hough matrix RANSAC algorithm H-component

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Rooting Regional Characteristic Culture and Cultivating Students Design Consciousness:Taking the Teaching Reform of Architectural Landscape Design as an Example

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Asian Agricultural Research 2020年第9期12卷 70-72页

作者： Haifang HE kan zheng College of City Construction Jiangxi Normal UniversityNanchang 330022China

China has a vast territory and numerous ethnic groups,forming various regional cultures with different styles.However,the architectural design education in colleges and universities of China used to learn from the West,and there is homogeneity in teaching mode,teaching content,and curriculum system construction,lacking regional cultural characteristics.In the context of regional culture,combined with the cultivation of students'innovation ability,the teaching of the course of Architectural Landscape Design is discussed in this article,in order to promote the inheritance and development of regional culture in landscape design teaching and promote students to truly understand the artistry and practicality of regional cultural resources.

关键词： Regional culture Architectural landscape design Design consciousness

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Design and experiment of anti-vibrating and anti-wrapping rotary components for subsoiler cum rotary tiller

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International Journal of Agricultural and Biological Engineering 2019年第4期12卷 47-55页

作者： kan zheng Allen D.McHugh Hongwen Li Qingjie Wang Caiyun Lu Hongnan Hu Wenzheng Liu Zhiqiang Zhang Peng Liu Jin He College of Engineering China Agricultural UniversityBeijing 100083China International Maize and Wheat Improvement Centre(CIMMYT) Dhaka 1213Bangladesh

The commonly used subsoiling cum rotary tiller machine(SRT)in Northern China is a combination of subsoiler and horizontal rotary tiller,however backfilling of the subsoiling slot,excessive vibration and plant residue wrapping on rotary components has been rarely considered.Therefore,the rotary components and assembly were redesigned to address these issues and to an SRT fitted with IT225 short curve rotary blades behind the V-shape subsoiling slots and IIT245 long curve rotary blades between the tines.Long and short blades were fitted on a rotor in a double helix,with optimal spiral angles of 65° and 90°,and phase angle of 147°and 180°,respectively.Compared with the commonly used SRT(CSRT),the additional anti-wrapping cutting blades in the circumferential and axial direction of ASRT could remove hanging residue on the blade holders,wrapping on the rotor and formation of an isolation layer.Moreover,the cutting edge curve of anti-wrapping cutting blades was an exponential curve.Field tests demonstrated that the redesigned SRT with anti-vibrating and anti-wrapping rotary components(ASRT)had was a significant advancement over the CSRT.Moreover,the working depth of rotary tillage was more stable,while other observations confirmed that backfilling of the subsoiling slot was also improved.

关键词： subsoiling rotary tiller anti-vibration anti-wrapping backfill tillage

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Development Strategy of Soundscape in Rural Tourism Based on Tourist Perception:A Case Study of Some Villages in Jiangxi Province

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Asian Agricultural Research 2020年第12期12卷 54-57页

作者： kan zheng Haifang HE Jiawei GAO College of City Construction Jiangxi Normal University Nanchang 330022 China College of Architecture and Urban Planning Guangzhou University Guangzhou 510006 China

In the context of the development of rural tourism,through the field investigation of several rural tourism destinations in Jiangxi,and from the perspective of tourist perception,this paper discusses the development s... 详细信息

关键词： Tourist perception Rural tourism Soundscape design Development strategy

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Analysis of Comprehensive Utilization of Coconut Waste

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Asian Agricultural Research 2013年第10期5卷 84-87页

作者： kan zheng Dong LIANG Xirui ZHANG School of Mechanics and Electrics Engineering Hainan University

This paper describes and analyzes the coconut cultivation in China,and the current comprehensive utilization of waste resources generated during cultivation and processing of coconut.The wastes generated in the process of cultivation include old coconut tree trunk,roots,withered coconut leaves,coconut flower and fallen cracking coconut,mainly used for biogas extraction,direct combustion and power generation,brewing,pharmacy,and processing of building materials;the wastes generated during processing include coconut water,coconut coat,coconut shell and coconut meal,mainly used for processing beverages,pharmaceutical products,activated carbon,medium and feed.This paper analyzes and explores some problems in the process of comprehensive utilization of coconut waste in China,such as insufficient understanding,inadequate development and lack of research efforts,and finally puts forth the corresponding development countermeasures.

关键词： Coconut Waste Comprehensive utilization

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