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Type synthesis of a new class of 4-3T1R(y) parallel mechanisms for parallel machine tools design

Discover Mechanical engineering 2024年第1期3卷 1-19页

作者： Wu, Shiyun Du, Jianjun Pan, Jianfei Lei, Jianguo School of Mechanical Engineering and Automation Harbin Institute of Technology (Shenzhen) Shenzhen 518055 China College of Mechatronics and Control Engineering Shenzhen University Shenzhen 518061 China

Unlike previous design procedures for parallel machine tools (PMTs), this paper first analyzes the path and posture requirements of the tools in universal processing, then proposes and constructs a new class of PMs that can provide the required path and posture. This opens up new ideas for the design of PMTs. Based on the reciprocal screw theory, a type synthesis process of asymmetrical lower-mobility PMs was proposed. Through this process, a novel class of four-limbed parallel mechanisms (PMs) providing three translations and one rotation around a horizontal axis (y-axis), denoted as 4-3T1R(y) PMs, was successfully proposed and constructed. Such PMs can be applied to the design of PMTs, especially the design of micro-electrical discharge machining (micro-EDM) PMTs. The structural design of a new 2RRC-2CRU PM, which was a member of 4-3T1R(y) PMs, was performed, and its mobility was analyzed in detail to demonstrate the efficiency of the proposed type synthesis process. The inverse, forward, and velocity kinematics problems of the 2RRC-2CRU PM were solved for further applications. © The Author(s) 2024.

关键词： Kinematics problem Parallel machine tools Parallel mechanisms Type synthesis

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Robust Stability and Stabilizability Conditions for Time-Delay Systems Under Stochastic Uncertainties

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IEEE Transactions on Automatic control 2024年第6期70卷 4037-4044页

作者： Chen, Jianqi Mao, Qi Zhao, Di Chen, Chao Nanjing University Center for Advanced Control and Smart Operations Suzhou China Nanjing Normal University School of Electrical and Automation Engineering Nanjing China Tongji University Department of Control Science and Engineering Shanghai Institute of Intelligent Science and Technology Shanghai China Leuven3001 Belgium

This study first explores the mean-square robust stability problem of stable continuous-time linear time-invariant systems subject to stochastic multiplicative uncertainties with prescribed variance bounds. The internal structures of uncertainties, however, are not presumed to cope with diverse random noises and errors arising from networked channels. A necessary and sufficient mean-square stability condition is obtained involving a novel small-gain type characterization. Next, we consider the output feedback controller synthesis problem of networked control systems facing stochastic multiplicative uncertainties and intrinsic channel-wise time delays simultaneously. Based on the obtained mean-square stability condition, further, we develop a fundamental necessary and sufficient condition of mean-square stabilizability explicitly. Such a condition equivalently determines that an open-loop unstable system can be stabilized by output feedback in the mean-square sense. Finally, an analysis of delay robustness is elaborated, in which the mean-square stabilizability condition is extended to the case tolerating uncertain but upper-bounded time delays. Overall, this study provides a comprehensive analysis of the robust mean-square stability and mean-square stabilizability of time-delay systems under stochastic uncertainties, which can have practical implications for networked control systems. © 1963-2012 IEEE.

关键词： Continuous time systems

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Preliminary study of the electrospray DPE peculiarities from the liquid surface in the presence of the CSWs

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Plasma Science and Technology 2024年第5期26卷 110-120页

作者：贺伟国霍卫杰韩罗峰朱康武王锋王泽坤 School of Mechatronic Engineering and Automation Shanghai UniversityShanghai 200444People’s Republic of China Shanghai Aerospace Electronic Technology Institute Shanghai 201109People’s Republic of China Shanghai Aerospace Control Technology Institute Shanghai 201109People’s Republic of China

The Ultrasonic Electric Propulsion(UEP)system is a cutting-edge propulsion technology that is mostly used on platforms for small satellites(less than 10 kg).The characteristics of droplet partial emissions(DPEs)in the UEP system are investigated using a high-speed imaging technique(an ultra-high speed camera(NAC HX-6)and a long-distance microscope)in this *** experiments demonstrate that there are a few partial emission modes,including left-side emission,double-side emission,and right-side emission,that are present in the droplet emission process of the UEP *** modes are primarily caused by the partial formation of capillary standing waves(CSWs)on the emission surface of the ultrasonic *** emission rate for single-and double-sided emissions varies at different times,indicating that there are different CSWs engaged in droplet emission due to variations in the liquid film thickness and charge state of the liquid ***,as the droplets emit continuously,a raised area on the emission surface appears,with several droplets emitting there as a result of charge ***,photos of the CSWs with emitting droplets are obtained,which highlights the CSWs'distinctive wave morphology.

关键词： ultrasonic electric propulsion system microsatellite high-speed imaging technique droplet partial emissions electric field

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A Novel Belief Rule-Based Fault Diagnosis Method with Interpretability

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Computer Modeling in engineering & Sciences 2023年第8期136卷 1165-1185页

作者： Zhijie Zhou Zhichao Ming Jie Wang Shuaiwen Tang You Cao Xiaoxia Han Gang Xiang Rocket Force University of Engineering Xi’an710025China School of Automation Science and Electrical Engineering Beihang UniversityBeijing100191China Beijing Aerospace Automatic Control Institute Beijing100070China

Fault diagnosis plays an irreplaceable role in the normal operation of equipment.A fault diagnosis model is often required to be interpretable for increasing the trust between humans and the *** to the understandable knowledge expression and transparent reasoning process,the belief rule base(BRB)has extensive applications as an interpretable expert system in fault *** is an effective means to weaken the subjectivity of experts in BRB,where the interpretability of BRB may be ***,to obtain a credible result,the weakening factors of interpretability in the BRB-based fault diagnosis model are firstly analyzed,which are manifested in deviation from the initial judgement of experts and over-optimization of *** these two factors,three indexes are proposed,namely the consistency index of rules,consistency index of the rule base and over-optimization index,tomeasure the interpretability of the *** both the accuracy and interpretability of amodel,an improved coordinate ascent(I-CA)algorithmis proposed to fine-tune the parameters of the fault diagnosis model based on *** I-CA,the algorithm combined with the advance and retreat method and the golden section method is employed to be one-dimensional search ***,the random optimization sequence and adaptive step size are proposed to improve the accuracy of the ***,a case study of fault diagnosis in aerospace relays based on BRB is carried out to verify the effectiveness of the proposed method.

关键词： Fault diagnosis belief rule base interpretability weakening factors improved coordinate ascent

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Predefined-Time Distributed Fault-Tolerant control for Nonlinear Multiagent Systems Suffering From Nonaffine Faults

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IEEE Transactions on Systems, Man, and Cybernetics: Systems 2025年第5期55卷 3300-3311页

作者： Cheng, Shuai Xin, Bin Chen, Jie Deng, Fang Qingdao University School of Automation Qingdao266071 China Beijing Institute of Technology School of Automation Beijing100081 China Beijing Institute of Technology National Key Laboratory of Autonomous Intelligent Unmanned Systems Beijing100081 China Shanghai Research Institute for Intelligent Autonomous Systems Tongji University Department of Control Science and Engineering Shanghai200092 China

This article investigates the distributed predefined-time (PT) fault-tolerant control for nonlinear multiagent systems (NNMSs) with nonaffine faults. A novel distributed PT control scheme is proposed based on a new PT theorem. The switching functions are introduced into distributed control signals to avoid the singularity problem. The second-order filter technology is designed to solve "explosion of complexity" issues. The newly designed PT compensation signals are utilized to eliminate filter errors. The proposed distributed PT controller based on local information can guarantee that all signals of the closed-loop system are PT bounded, and consensus errors of NNMSs can be enforced to a small region around the origin within a predefined time. Compared with the finite/fixed time, the predefined time is an exact value given in advance, which remains constant regardless of initial states and control parameters. Finally, two comparative simulations are provided to demonstrate the presented strategy. © 2013 IEEE.

关键词： Adaptive control systems

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Toward Automating the Composition of Digital Twins Within System-of-Systems 29

Toward Automating the Composition of Digital Twins Within Sy...

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29th IEEE International Conference on Emerging Technologies and Factory automation, ETFA 2024

作者： Gill, Milapji Singh Zhang, Jingxi Wortmann, Andreas Fay, Alexander Institute of Automation Technology Helmut Schmidt University Hamburg Germany Institute of Control Engineering of Machine Tools and Manufacturing Units University of Stuttgart Germany Automation Ruhr University Bochum Germany

ISBN: (纸本)9798350361230

Cyber-Physical Production Systems necessitate efficient configuration and continuous reconfiguration to adapt to evolving requirements and shifting goals. This process involves integrating various system structures to derive new functions and behaviors. The concept of the Digital Twin, which allows for effective integration and testing, is instrumental in facilitating this task. However, a fundamental prerequisite is that Digital Twins of individual system components must be composed efficiently and in accordance with dynamic System-of-Systems. We address this challenge by introducing an approach for the automated horizontal and vertical composition of Digital Twins, aimed at minimizing manual intervention and enhancing adaptability. Therefore, a pipeline specifically designed for this goal is proposed, which includes the generation of new functions and behaviors. This approach is intended to provide a foundation for future research. © 2024 IEEE.

关键词： System of systems

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Distributed formation control of multiple aerial vehicles based on guidance route

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Chinese Journal of Aeronautics 2023年第3期36卷 368-381页

作者： Jinyong CHEN Rui ZHOU Guibin SUN Qingwei LI Ning ZHANG School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China Science and Technology on Information Systems Engineering Laboratory Nanjing 210007China AVIC Xi’an Flight Automatic Control Research Institute Xi’an 710076China

Formation control of fixed-wing aerial vehicles is an important yet rarely addressed problem because of their complex dynamics and various motion constraints,such as nonholonomic and velocity *** guidance-route-based strategy has been demonstrated to be applicable to fixed-wing ***,it requires a global coordinator and there exists control lag,due to its own *** this reason,this paper presents a fully distributed guidance-route-based formation approach to address the aforementioned ***,a hop-count scheme is introduced to achieve distributed implementation,in which each aircraft chooses a neighbor with the minimum hop-count as a reference to generate its guidance route using only local ***,the model predictive control algorithm is employed to eliminate the control lag and achieve precise formation shape *** addition,the stall protection and collision avoidance are also ***,three numerical simulations demonstrate that our proposed approach can implement precise formation shape control of fixed-wing aircraft in a fully distributed manner.

关键词： Formation shape control Fixed-wing aircraft Guidance route Hop-count estimation Model predictive control

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Object Helps U-Net Based Change Detectors

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IEEE/CAA Journal of Automatica Sinica 2024年第2期11卷 548-550页

作者： Lan Yan Qiang Li Kenli Li College of Computer Science and Electronic Engineering Hunan UniversityChangsha 410082China State Key Laboratory for Management and Control of Complex Systems Institute of AutomationChinese Academy of SciencesBeijing 100190China

Dear Editor,This letter focuses on leveraging the object information in images to improve the performance of the U-Net based change *** detection is fundamental to many computer vision *** existing solutions based on ... 详细信息

关键词： Net computer networks

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An adaptive large neighborhood search for the multi-point dynamic aggregation problem

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control Theory and Technology 2024年第3期22卷 360-378页

作者： Shengyu Lu Bin Xin Jie Chen Miao Guo School of Automation Beijing Institute of TechnologyBeijing 100081China National Key Lab of Autonomous Intelligent Unmanned Systems Beijing 100081China Department of Control Science and Engineering Tongji UniversityShanghai 201804China

The multi-point dynamic aggregation(MPDA)problem is a challenging real-world *** the MPDA problem,the demands of tasks keep changing with their inherent incremental rates,while a heterogeneous robot fleet is required to travel between these tasks to change the time-varying state of each *** robots are allowed to collaborate on the same task or work separately until all tasks are *** is challenging to generate an effective task execution plan due to the tight coupling between robots abilities and tasks'incremental rates,and the complexity of robot *** effectiveness consideration,we use the variable length encoding to avoid redundancy in the solution *** creatively use the adaptive large neighborhood search(ALNS)framework to solve the MPDA *** the proposed algorithm,high-quality initial solutions are generated through multiple problem-specific solution construction *** heuristics are also used to fix the broken solution in the novel integrated decoding-construction repair process of the ALNS *** results of statistical analysis by the Wilcoxon rank-sum test demonstrate that the proposed ALNS can obtain better task execution plans than some state-of-the-art algorithms in most MPDA instances.

关键词： Adaptive large neighborhood search(ALNS) Multi-point dynamic aggregation(MPDA) Heuristic solution construction Multi-robot collaboration

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Plant Disease Detection Using Machine Learning 4

Plant Disease Detection Using Machine Learning

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4th International Conference on Intelligent Technologies, CONIT 2024

作者： Parida, Amit Kumar Stonier, Albert Alexander Vit University School of Electrical Engineering Department of Control and Automation Vellore India Vellore Institute of Technology School of Electrical Engineering Vellore India

ISBN: (纸本)9798350349900

Plant diseases are a serious threat toworld agriculture, resulting in lower agricultural yields and financial losses. This study examines how machine learning methods could revolutionize the identification of plant diseases. The shortcomings of conventional approaches and suggest combining machine learning models with cutting-edge imaging and data processing technologies to improve the diagnosis's speed and precision. This research demonstrates how well machine learning methods, such as CNN and SVM, can distinguish between healthy and unhealthy plants. Also gone through how transfer learning can be used, especially when data is scarce, to modify previously trained models for illness detection. © 2024 IEEE.

关键词： Adversarial machine learning

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