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Additive Manufacturing 2025年 107卷

作者： Sun, Manyou Mohammadnejad, Ali Toyserkani, Ehsan Lab Department of Mechanical and Mechatronics Engineering University of Waterloo WaterlooONN2L 3G1 Canada

This work discloses the preliminary results of a feasibility study of a novel setup and procedure for electropolishing internal channels of additively manufactured components. A specially designed and printed polymeric cover was assembled with a flexible stainless steel 316 wire to facilitate electropolishing of internal channels with various curvatures. A numerical simulation was conducted for optimization of wire cover designs, and the performance of three designs were analyzed and compared. Following that, experimental studies were conducted to assess the feasibility of the process. The presence of curvatures was found to influence the formation and removal of conductive solid reaction products, thus affecting the electropolishing performance accordingly. A maximum surface roughness Sa reduction from 10.86 ± 0.50 μm to 1.44 ± 0.46 μm was obtained for straight channels after electropolishing for 20 min, while less efficient surface smoothening performance was observed on curved channels. While challenges need to be solved for improving the electropolishing performance and reducing the limit of the channel size that can be electropolished, the methods show significant potential on electropolishing curved internal channels, which can be further used in industrial-scale applications. © 2025 The Authors

关键词： Electropolishing Additive manufacturing Internal channels Surface roughness

Global solution to sensor network localization: A non-convex potential game approach and its distributed implementation

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arXiv 2024年

作者： Xu, Gehui Chen, Guanpu Hong, Yiguang Fidan, Baris Parisini, Thomas Johansson, Karl H. Key Laboratory of Systems and Control Academy of Mathematics and Systems Science Beijing100190 China The Division of Decision and Control Systems School of Electrical Engineering and Computer Science KTH Royal Institute of Technology Sweden Digital Futures StockholmSE-10044 Sweden Department of Control Science and Engineering Tongji University Shanghai201804 China Shanghai Research Institute for Intelligent Autonomous Systems Shanghai201210 China The Department of Mechanical and Mechatronics Engineering University of Waterloo WaterlooONN2L 3G1 Canada The Department of Electrical and Electronic Engineering Imperial College London LondonSW7 2AZ United Kingdom The Department of Engineering and Architecture University of Trieste Trieste34127 Italy

Consider a sensor network consisting of both anchor and non-anchor nodes. We address the following sensor network localization (SNL) problem: given the physical locations of anchor nodes and relative measurements among all nodes, determine the locations of all non-anchor nodes. The solution to the SNL problem is challenging due to its inherent non-convexity. In this paper, the problem takes on the form of a multi-player nonconvex potential game in which canonical duality theory is used to define a complementary dual potential function. After showing the Nash equilibrium (NE) correspondent to the SNL solution, we provide a necessary and sufficient condition for a stationary point to coincide with the NE. An algorithm is proposed_ to reach the NE and shown to have convergence rate O(1/√k). With the aim of reducing the information exchange within a network, a distributed algorithm for NE seeking is implemented and its global convergence analysis is provided. Extensive simulations show the validity and effectiveness of the proposed approach to solve the SNL problem. Copyright © 2024, The Authors. All rights reserved.

关键词： Game theory

Directed energy deposition powder stream modeling using a Gaussian beam ray representation

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arXiv 2022年

作者： Martinez-Marchese, Alexander Klumpp, Maximilian Toyserkani, Ehsan Lab Department of Mechanical and Mechatronics Engineering University of Waterloo WaterlooONN2L 3G1 Canada Institute of Analysis Dynamics and Modeling University of Stuttgart Pfaffenwaldring 57 Stuttgart70569 Germany

The powder stream from a side feed nozzle, or part of the powder stream in some coaxial nozzles, in a directed energy deposition via powder feeding (DED-PF) machine, can be modeled using a particle velocity field that has a constant downward component and a linearly increasing outward component, in proportion to the powder stream's center line distance [1]. However, when the powder stream is subject to a force field, it was found that the shape of the powder concentration function close to the center of the powder stream diverges considerably at high degrees of focusing. This discrepancy is reduced by modeling the powder stream based on the ray representation of a Gaussian beam [2]. Experimental results from high-speed camera particle tracking and numerically extrapolating the trajectories to the nozzle exit suggests that the statistics of the powder stream correspond to this model. A novel method to compute the particle concentration along the stream using an optical system analog, with the focusing force field modeled as the transfer matrix of a graded refractive index (GRIN) lens, is also demonstrated. This method is orders of magnitude faster than the corresponding Lagrangian simulation. Copyright © 2022, The Authors. All rights reserved.

关键词： Gaussian beams

Fabrication of Translucent Graded Dental Crown Using Zirconia-Yttrium Multi-Slurry Tape Casting 3d Printer

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SSRN

SSRN 2024年

作者： Romario, Yulius Shan Bhat, Chinmai Ramezani, Maziar Pasang, Tim Chen, Zhangwei Jiang, Cho-Pei Graduate Institute of Manufacturing Technology National Taipei University of Technology 1 Sec. 3 Zhongxiao E. Rd. Taipei10608 Taiwan High-value Biomaterials Research and Commercialization Center National Taipei University of Technology 1 Sec. 3 Zhongxiao E. Rd. Taipei10608 Taiwan Department of Mechanical Engineering Auckland University of Technology Auckland1010 New Zealand Department of Engineering Design Manufacturing and Management Systems Western Michigan University KalamazooMI4900-5200 United States Additive Manufacturing Institute Shenzhen University Shenzhen518060 China Guangdong Key Laboratory of Electromagnetic Control and Intelligent Robotics College of Mechatronics and Control Engineering Shenzhen University Shenzhen518060 China Department of Mechanical Engineering National Taipei University of Technology Taiwan 1 Sec. 3 Zhongxiao E. Rd. Taipei10608 Taiwan

This paper aims to fabricate functionally graded dental crown using a multi-slurry tape casting additive manufacturing technology. The different luminescence of the dental crown was obtained with different composition of zirconia and yttria. Zirconia with tunable mechanical properties and translucency are obtained by adding 3, 3.5, 4, 4.5, and 5 mol% of yttrium oxide to zirconia powder. After obtaining the printable slurry with maximum solid loading, the green bodies are prepared using the in-house built high speed multi-ceramic tape casting technology. They are later sintered with two-stage sintering method. After the successful fabrication, the mechanical properties and translucency of the specimens were evaluated with Vickers hardness, three-point bending and translucency parameter tests. Finally, an FGM tooth crown with five photocurable slurries is proposed to demonstrate the translucent gradient effect of sintered part. The solid loading of 80% zirconia and 20% resin delivered samples without any surface cracks. The shrinkage ratio analysis showed that the sintered sample dimension was reduced by 20%, 20%, and 23% along X, Y, and Z directions. The samples fabricated with 3% yttrium oxide to zirconia delivered excellent hardness (1687 HV) and flexural strength (650.6 MPa). However, the relative luminescence increased with increasing the yttrium oxide for 3 – 5 mol%. With the optimized process parameters, the proposed dental crown is fabricated and analyzed for their shrinkage ratio, mechanical, and translucency properties. The study proposes the potential of fabricating customized dental crown with gradient translucent appearance. © 2024, The Authors. All rights reserved.

关键词： Zirconia

A Fair and Effective Approach to Managing Distributed Energy Resources Through Peer-to-Peer Energy Trading with Load Prioritization Among Smart Homes

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SSRN

SSRN 2023年

作者： Ahmed, Syed Adrees Huang, Qi Amin, Waqas Afzal, Muhammad Hussain, Fazal Haider, Muhammad Husnain 1Sichuan Provincial Key Lab of Power System Wide-Area Measurement and Control School of Mechanical and Electrical Engineering University of Electronic Science and Technology of China Sichuan China Chengdu University of Technology China National University of Sciences and Technology Pakistan Superior University Pakistan School of Mechanical and Electrical Engineering University of Electronic Science and Technology of China Sichuan China

This paper proposes a novel approach to managing distributed energy resources (DERs) through peer-to-peer (P2P) energy trading among smart homes, incentivizing peers to trade surplus energy to maximize social welfare. The proposed day-ahead demand-side management (DSM) technique considers load prioritization based on users' needs. It utilizes an energy allocation method that incentivizes peers to buy energy at a reduced price and sell energy at a higher price. This method maximizes the time of energy traded to higher-priority loads, followed by lower-priority loads while considering user choice. The proposed method results in an average reduction in energy costs from 14.8% to 2.82% for all consumers and an average increase in revenues from 17.35% to 9.07% for all prosumers compared to the grid and previously proposed studies. The simulation results show significant economic benefits for all market participants, improved community self-sufficiency, and reduced dependence on the main grid. The proposed methodology provides an effective and fair solution for managing DERs through P2P energy trading by prioritizing the load in smart homes, which describes its potential to create a sustainable and efficient energy ecosystem. © 2023, The Authors. All rights reserved.

关键词： Automation

Forward Calculation Model for Utilization of Energy and Mass in Laser-Directed Energy Deposition

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SSRN

SSRN 2022年

作者： Ren, Ke Di, Yuelan Wang, Gang Wang, Liping Wang, Haidou Rong, Yiming School of Mechatronics Engineering Harbin Institute of Technology Harbin150001 China Department of Mechanical and Energy Engineering Southern University of Science and Technology Shenzhen518055 China Department of Equipment Support and Remanufacturing Army Academy of Armored Forces Beijing100072 China Beijing Key Lab of Precision/Ultra-precision Manufacturing Equipments and Control Department of Mechanical Engineering Tsinghua University Beijing100084 China

Precise control of energy and mass utilization is essential for the process design and optimization of powder-based laser-directed energy deposition (L-DED). However, fully comprehending the actual changes in the energy and the mass, which have complex nonlinear relationships with all inputs, is still challenging. In powder-based L-DED, the energy absorptivity is closely related to the powder catchment efficiency, owing to the effects of the laser incidence angle and the material properties. In this study, a forward calculation model was established for the utilization of energy and mass in powder-based L-DED without data regression of experimental measurements. Interactions between the laser, powders, and substrate were analyzed in detail in terms of three major effects: energy absorption of the substrate, powder catchment, and deposition shape variation. A secondary correction of the incidence angle was included in the geometric change of the deposited passes, and the boundary shift of the molten pool, which resulted from the melting point differences of the dissimilar deposited and substrate materials, was considered. The model prediction results matched the multipass deposition experimental results well. The average prediction error validated that the catchment efficiency did not exceed 5.2%. The scanning speed and the powder feed rate showed the largest effects on the energy absorptivity, which varied in the range of approximately 40%–65%. The developed model presents good universality and can be fundamental for understanding the forming mechanism, optimizing the process, and predicting the deposition quality of powder-based L-DED. © 2022, The Authors. All rights reserved.

关键词： Catchments

Fabrication grammars: bridging design and robotics to control emergent material expressions

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Construction Robotics 2021年第1期5卷 35-48页

作者： Iremnur Tokac Johan Philips Herman Bruyninckx Andrew Vande Moere Design Department of Architecture KU Leuven Leuven Belgium Robotics Automation and Mechatronics Department of Mechanical Engineering KU Leuven Leuven Belgium Flanders Make@KU Leuven Core Lab ROB Heverlee Belgium Control Systems Technology Department of Mechanical Engineering Technical University Eindhoven Eindhoven Netherlands

Designers physically engage with a material to experience how certain characteristics allow the fabrication of unique expressions. In digital fabrication, however, this improvisational negotiation is typically replaced by a virtual simulation that predicts how a material expression can be fabricated, limiting the resulting design language to algorithmic forms. In contrast, we believe that digital fabrication can also produce ‘emergent’ material expressions that are so confounded that they appear slightly differently even when being produced by identical operations. This paper argues that such expressions can be executed by a domain-driven feedback paradigm, which integrates a human-in-the-loop to encode the tacit fabrication knowledge that is generated by reviewing intermediate outcomes. We encode this tacit knowledge by fabrication grammars, rule-based descriptions that causally relate fabrication parameters to qualitative descriptions of material expressions. By documenting a set of Single Point Incremental Forming experiments, this paper demonstrates how emergent material expressions can be controlled by semantically meaningful fabrication grammars, which even can be combined towards purposeful design goals. We believe our findings might allow the digital fabrication of material expressions that appear to have been produced manually or naturally; and support the future sharing of tacit fabrication knowledge.

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A Multi-Player Potential Game Approach for Sensor Network Localization with Noisy Measurements

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arXiv 2024年

作者： Xu, Gehui Chen, Guanpu Fidan, Baris Hong, Yiguang Qi, Hongsheng Parisini, Thomas Johansson, Karl H. The Key Laboratory of Systems and Control Academy of Mathematics and Systems Science Beijing China The Division of Decision and Control Systems School of Electrical Engineering and Computer Science KTH Royal Institute of Technology Stockholm100 44 Sweden The Division of Decision and Control Systems School of Electrical Engineering and Computer Science KTH Royal Institute of Technology Stockholm100 44 Sweden The Department of Mechanical and Mechatronics Engineering University of Waterloo WaterlooONN2L 3G1 Canada Department of Control Science and Engineering Tongji University Shanghai201804 China Shanghai Research Institute for Intelligent Autonomous Systems Shanghai201210 China Key Laboratory of Systems and Control Academy of Mathematics and Systems Science Beijing China School of Mathematical Sciences University of Chinese Academy of Sciences Beijing China The Department of Electrical and Electronic Engineering Imperial College London LondonSW7 2AZ United Kingdom The Department of Engineering and Architecture University of Trieste Trieste34127 Italy

Sensor network localization (SNL) is a challenging problem due to its inherent non-convexity and the effects of noise in inter-node ranging measurements and anchor node position. We formulate a non-convex SNL problem as a multi-player non-convex potential game and investigate the existence and uniqueness of a Nash equilibrium (NE) in both the ideal setting without measurement noise and the practical setting with measurement noise. We first show that the NE exists and is unique in the noiseless case, and corresponds to the precise network localization. Then, we study the SNL for the case with errors affecting the anchor node position and the inter-node distance measurements. Specifically, we establish that in case these errors are sufficiently small, the NE exists and is unique. It is shown that the NE is an approximate solution to the SNL problem, and that the position errors can be quantified accordingly. Based on these findings, we apply the results to case studies involving only inter-node distance measurement errors and only anchor position information inaccuracies. Copyright © 2024, The Authors. All rights reserved.

关键词： Sensor nodes

Non-convex potential games for finding global solutions to sensor network localization

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arXiv 2023年

作者： Xu, Gehui Chen, Guanpu Hong, Yiguang Fidan, Baris Parisini, Thomas Johansson, Karl H. Key Laboratory of Systems and Control Academy of Mathematics and Systems Science Beijing China Division of Decision and Control Systems School of Electrical Engineering and Computer Science KTH Royal Institute of Technology Stockholm100 44 Sweden Department of Control Science and Engineering Tongji University Shanghai201804 China Shanghai Research Institute for Intelligent Autonomous Systems Shanghai201210 China Department of Mechanical and Mechatronics Engineering University of Waterloo WaterlooONN2L 3G1 Canada Department of Electrical and Electronic Engineering Imperial College London LondonSW7 2AZ United Kingdom Department of Engineering and Architecture University of Trieste Trieste34127 Italy

Sensor network localization (SNL) problems require determining the physical coordinates of all sensors in a network. This process relies on the global coordinates of anchors and the available measurements between non-anchor and anchor nodes. Attributed to the intrinsic non-convexity, obtaining a globally optimal solution to SNL is challenging, as well as implementing corresponding algorithms. In this paper, we formulate a non-convex multi-player potential game for a generic SNL problem to investigate the identification condition of the global Nash equilibrium (NE) therein, where the global NE represents the global solution of SNL. We employ canonical duality theory to transform the non-convex game into a complementary dual problem. Then we develop a conjugation-based algorithm to compute the stationary points of the complementary dual problem. On this basis, we show an identification condition of the global NE: the stationary point of the proposed algorithm satisfies a duality relation. Finally, simulation results are provided to validate the effectiveness of the theoretical results. Copyright © 2023, The Authors. All rights reserved.

关键词： Sensor networks

Decision-Making in Driver-Automation Shared control:A Review and Perspectives

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IEEE/CAA Journal of Automatica Sinica 2020年第5期7卷 1289-1307页

作者： Wenshuo Wang Xiaoxiang Na Dongpu Cao Jianwei Gong Junqiang Xi Yang Xing Fei-Yue Wang IEEE California PATH University of CaliforniaBerkeleyCA 94720 USA Department of Engineering University of CambridgeCambridge CB21PZU.K. Mechanical and Mechatronics Engineering University of WaterlooWaterloo N2L3G1Canada Department of Mechanical Engineering Beijing Institute of TechnologyBeijing 100081China School of Mechanical and Aerospace Engineering Nanyang Technological UniversitySingapore 639798Singapore State Key Laboratory for Management and Control of Complex Systems Institute of AutomationChinese Academy of SciencesBeijing 100190and also with the Research Center for Military Computational Experiments and Parallel Systems TechnologyNational University of Defense TechnologyChangsha 410073China

Shared control schemes allow a human driver to work with an automated driving agent in driver-vehicle systems while retaining the driver’s abilities to *** human driver,as an essential agent in the driver-vehicle shared control systems,should be precisely modeled regarding their cognitive processes,control strategies,and decision-making *** interactive strategy design between drivers and automated driving agents brings an excellent challenge for human-centric driver assistance systems due to the inherent characteristics of *** open-ended questions arise,such as what proper role of human drivers should act in a shared control scheme?How to make an intelligent decision capable of balancing the benefits of agents in shared control systems?Due to the advent of these attentions and questions,it is desirable to present a survey on the decision making between human drivers and highly automated vehicles,to understand their architectures,human driver modeling,and interaction strategies under the driver-vehicle shared ***,we give a further discussion on the key future challenges and *** are likely to shape new potential research directions.

关键词： Automated vehicle decision-making human driver human-vehicle interaction shared control