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arXiv 2022年

作者： Hashemi, Seyed Hamed Mattila, Jouni The Faculty of Engineering and Natural Sciences Unit of Automation Technology and Mechanical Engineering Tampere University Tampere Finland

This paper examines the global convergence problem of SLAM algorithms, an issue that faces topological obstructions. This is because the state-space of attitude dynamics is defined on a non-contractible manifold: the special orthogonal group of order three SO(3). Therefore, this paper presents a novel, gradient-based hybrid observer to overcome these topological obstacles. The Lyapunov stability theorem is used to prove the globally asymptotic convergence of the proposed algorithm. Finally, comparative analyses of two simulations were conducted to evaluate the performance of the proposed scheme and to demonstrate the superiority of the proposed hybrid observer to a smooth observer. Copyright © 2022, The Authors. All rights reserved.

关键词： Hybrid systems

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Robust Model Predictive Control for Robot Manipulators

Robust Model Predictive Control for Robot Manipulators

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IEEE-RAS International Conference on Humanoid Robots

作者： S. Mohammad Tahamipour-Z. Goran R. Petrovic Jouni Mattila Automation Technology and Mechanical Engineering Unit in the Faculty of Engineering and Natural Sciences Tampere University Tampere Finland

ISBN: (纸本)9798350309805

Inherent nonlinearities, external disturbances and model uncertainties hinder the performance of controlling real-world systems. In the present study, we proposed a robust model prediction-based virtual decomposition control method (RMP-VDC) as a modification of the VDC using the model predictive control (MPC) to offer a practical solution for the real system control problem. The proposed method deals with uncertainties and external forces, as well as constraint matters, for complex nonlinear robot manipulators. By modifying the ideas from the VDC with MPC techniques, the time-varying state feedback control law for the ancillary controller is provided. The proposed method benefits from the introduction of a prediction horizon, which induces robustness and increases accuracy. The constrained optimization problem is analytically solved online by the continuous linearization of the nonlinear model and by employing the active set method. To validate the proposed controller, we performed the implementation on a real 7-degrees-of-freedom upper body exoskeleton robot, and the results were compared with those obtained using the adaptive VDC. The experimental results revealed increased accuracy for the proposed RMP-VDC in dealing with model uncertainties and interaction forces between humans and exoskeleton robots.

关键词： Adaptation models State feedback Uncertainty TV Exoskeletons Humanoid robots Predictive models

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Coordination concepts for interactions between energy communities, markets, and distribution grids 26

Coordination concepts for interactions between energy commun...

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26th International Conference and Exhibition on Electricity Distribution, CIRED 2021

作者： Repo, Sami Attar, Mehdi Supponen, Antti Keski-Koukkari, Antti Safdarian, Amir Kulmala, Anna Vilkko, Matti Tampere University Unit of Electrical Engineering Tampere Finland VTT Technical Research Centre of Finland Espoo Finland Tampere University Unit of Automation Technology and Mechanical Engineering Tampere Finland

ISBN: (纸本)9781839535918

The paper summarizes the qualitative analysis of stakeholder interactions and coordination concepts in respect to four major congestion management solutions of distribution system operators. Benefits and drawbacks of congestion management solutions and interactions are analysed from holistic system perspective and concluded to understand the overall state-of-the-art and development needs. The key result of the analysis is that the winning approach for DSO CM includes all four CM solutions, and the next step is to incorporate technical active network management as novel operation tools for congestion management. © 2021 The Institution of engineering and technology.

关键词： Commerce

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DEEP MEAN-FIELD MODELING OF TRANSIENT AND POST-TRANSIENT, MULTI-ATTRACTOR FLOW DYNAMICS - EXEMPLIFIED FOR THE FLUIDIC PINBALL 12

DEEP MEAN-FIELD MODELING OF TRANSIENT AND POST-TRANSIENT, MU...

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12th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2022

作者： Deng, Nan Pastur, Luc R. Morzyński, Marek Noack, Bernd R. School of Mechanical Engineering and Automation Harbin Institute of Technology Shenzhen518055 China Unité de Mécanique IMSIA ENSTA-Paris Institut Polytechnique de Paris PalaiseauF-91120 France Department of Virtual Engineering Poznań University of Technology PoznańPL 60-965 Poland

We propose three kinds of mean-field modeling strategies for the complex dynamics generally found in fluid mechanics. A key enabler is a mean-field assumption, where slowly-varying mean-field deformations are due to the fluctuating field through the Reynolds stress, resulting in a Reynolds-like decomposition. We have developed projection-based and cluster-based reduced-order models, i.e., a least-order mean-field model for the successive bifurcations (Deng et al., 2020), an aerodynamic force model associated with a Galerkin model (Deng et al., 2021), and a hierarchical network model to automate the identification of multi-attractor dynamics (Deng et al., 2022). These mean-field models are exemplified for a challenging test case of the fluidic pinball at Re = 80, characterized by six invariant sets (three steady solutions and three limit cycles) induced by the first two successive bifurcations of pitchfork and Hopf types. This work shows a paradigm for automatable reduced-order modeling of complex flows using first principles and machine learning techniques, balancing between data-driven and physics-driven approaches and improving model interpretability and generalizability. © 2022 12th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2022. All rights reserved.

关键词： Reynolds number

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LPG vehicles’ adoption in Portugal: lessons for new AFV diffusion

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Transportation Research Procedia 2022年 62卷 688-695页

作者： Ana Paula Valente de Jesus Marta Ferreira Dias Margarida C. Coelho University of Aveiro Department of Economics Management and Industrial Engeneering Unit Research GOVCOPP Aveiro Portugal University of Aveiro Department of Mechanical Engineering Centre for Mechanical Technology and Automation Aveiro Portugal

Nonetheless the efforts of the different players, namely oil companies and fuelling stations owners, the liquid petroleum gas (LPG) does not play the role of an alternative to traditional fossil fuels yet. So far, LPG vehicles (LPGV) have failed in being widely accepted by users. Currently, LPGVs’ sales are already being surpassed by the "pro-electrification" group of vehicles formed by hybrids (HEV) and battery-electric vehicles (BEV). So, while establishing a parallel with LPGVs and natural gas vehicles (NGV) diffusion and adoption lessons learned, this paper explores alternative fuel vehicles (AFV) purchase’s intentions determinants and the eventual influence of socio-demographic characteristics. The results of a survey carried out to 189 individuals show fundamental differences within gender as well as between education level groups. HEVs are on top of women purchase intention ranking while men express preferences towards BEVs. NGVs and fuel cell electric vehicles (FCEV) are newcomers in this ranking. Meanwhile, LPGVs confirm a declining trend. Among AFV’s purchase intention determinants, low emissions, clean energy sources, affordable energy, and environmental concerns are the most frequently stated. The results also reveal significant differences in perceived AFV’s features between educational level groups, highlighting post-graduates’ answers, which leads us to conclude that qualification plays an essential role in how potential buyers perceive the vehicles and influences the purchase decision-making process. Finally, in this study, we also give implications for improving users’ knowledge and perception of AFVs and suggestions for future research.

关键词： vehicles adoption purchase intentions purchase decision determinants alternative fuel vehicles

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Optimal Switch and Tie Line Planning in Distribution Networks: Benchmarking a Practical MILP Model with a Fast Heuristic Approach

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IEEE Transactions on Power Systems 2024年

作者： Jooshaki, Mohammad Karimi-Arpanahi, Sahand Millar, R. John Anttila, Jaakko Lehtonen, Matti Fotuhi-Firuzabad, Mahmud Circular Economy Solutions Unit EspooFI-02151 Finland University of Adelaide School of Electrical and Mechanical Engineering AdelaideSA 5005 Australia Aalto University Department of Electrical Engineering and Automation Espoo02150 Finland Trimble Utilities & Public Administration - Europe Espoo02600 Finland Sharif University of Technology Electrical Engineering Department Tehran11155-4363 Iran

Optimal placement of switches and tie lines is an integral task in distribution system planning. Owing to the problem complexity and the presence of binary decision variables, using heuristic methods for obtaining a close to optimal switch and tie line plan is a common practice in industry. Efforts to employ mixed-integer linear programming (MILP) to guarantee the solution optimality also tend to sacrifice the modeling accuracy through oversimplifying assumptions to make the problem tractable. Aiming to tackle these challenges, we present an efficient, yet accurate, MILP model for optimal switch and tie line planning. The proposed model avoids common simplifying assumptions in the state-of-the-art MILP models while preserving the solving efficiency. In order to demonstrate the applicability and scalability of the proposed MILP approach, it is applied to multiple test networks, and the results are compared with those of a fast heuristic model. The outcomes not only represent the high efficiency and accuracy of the MILP model but also validate the close to optimality of the heuristic approach developed for practical applications as a module in a commercial distribution system planning toolbox. © 1969-2012 IEEE.

关键词： Mixed-integer linear programming

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Automatic Dataset Generation From CAD for Vision-Based Grasping

Automatic Dataset Generation From CAD for Vision-Based Grasp...

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International Conference on Advanced Robotics (ICAR)

作者： Saad Ahmad Kulunu Samarawickrama Esa Rahtu Roel Pieters Unit of Automation Technology and Mechanical Engineering Unit of Computing Sciences Tampere University Tampere Finland

ISBN: (纸本)9781665436854

Recent developments in robotics and deep learning enable the training of models for a wide variety of tasks, from large amounts of collected data. Visual and robotic tasks, such as pose estimation or grasping, are trained from image data (RGB-D) or point clouds that need to be representative for the actual objects, to acquire accurate and robust results. This implies either generalized object models or large datasets that include all object and environment variability, for training. However, data collection is often a bottleneck in the fast development of learning-based models. In fact, data collection might be impossible or even undesirable, as physical objects are unavailable or the physical recording of data is too time-consuming and expensive. For example, when building a data recording setup with cameras and robotic hardware. CAD tools, in combination with robot simulation, offer a solution for the generation of training data that can be easily automated and that can be just as realistic as real world data. In this work, we propose a data generation pipeline that takes as input a CAD model of an object and automatically generates the required training data for object pose estimation and object grasp detection. The object data generated are: RGB and depth image, object binary mask, class label and ground truth pose in camera- and world frame. We demonstrate the dataset generation of several sets of industrial object assemblies and evaluate the trained models on state of the art pose estimation and grasp detection approaches. Code and video are available at: https://***/KulunuOS/gazebo_dataset_generation.

关键词： Training Solid modeling Pose estimation Pipelines Training data Grasping Data collection

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MATHEMATICAL MODELLING AND VIRTUAL DECOMPOSITION CONTROL OF HEAVY-DUTY PARALLEL-SERIAL HYDRAULIC MANIPULATORS

arXiv

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arXiv 2021年

作者： Petrović, Goran R. Mattila, Jouni Faculty of Engineering and Natural Sciences Unit of Automation Technology Mechanical Engineering Tampere University Tampere Finland

This paper proposes a novel modelling approach for a heavy-duty manipulator with parallel-serial structures connected in series. Each considered parallel-serial structure contains a revolute segment with rigid links connected by a passive revolute joint and actuated by a linear hydraulic actuator, thus forming a closed kinematic loop. In addition, prismatic segments, consisting of prismatic joints driven by hydraulic linear actuators, also are considered. Expressions for actuator forces are derived using the Newton-Euler (N-E) dynamics formulation. The derivation process does not assume massless actuators decoupled from manipulator links, which is common in the Lagrange dynamics formulation. Actuator pressure dynamics are included in the analysis, leading in total to a third-order system of ordinary differential equations (ODEs). With fewer parameters than its predecessors, the proposed model in the N-E framework inspires revision of the virtual decomposition control (VDC) systematic process to formulate a control law based on the new model. The virtual stability of each generic manipulator revolute and prismatic segment is obtained, leading to the Lyapunov stability of the entire robot. © 2021, CC BY-NC-ND.

关键词： Manipulators

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Crack Development of Electroplated Niw Alloys and Their Wettability and Tribological Properties

SSRN

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SSRN 2024年

作者： Darayen, Jidsucha Ploypech, Suwat Metzner, Martin Santos, Claudia Beatriz dos Jearanaisilawong, Petch Boonyongmaneerat, Yuttanant Nanoscience and Technology Graduate School Chulalongkorn University Bangkok Thailand Fraunhofer Institute for Manufacturing Engineering and Automation Stuttgart Germany Department of Mechanical and Aerospace Engineering Faculty of Engineering King Mongkut’s University of Technology North Bangkok Bangkok Thailand Surface Coating Technology for Metals and Materials Research Unit Metallurgy and Materials Science Research Institute Chulalongkorn University Bangkok Thailand Faculty of Engineering Thammasat University Klong Nueng Klong Luang Pathumthani Thailand

This research explores the relationship between electrodeposition parameters, particularly tungsten content and current density, and the resulting properties of NiW coatings. Increased tungsten content systematically raises microcrack density, which enhances surface wettability by acting as lubricant reservoirs. The unique microstructure of NiW coatings, characterized by high crack density, also delivers exceptional wear resistance in both dry and wet conditions. As a potential alternative to conventional Cr coatings, NiW coatings offer superior performance and durability. This study highlights the importance of optimizing tungsten content and crack density to maximize the benefits of NiW coatings for advanced, wear-resistant applications. © 2024, The Authors. All rights reserved.

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Improving worker health and safety in wire arc additive manufacturing: A graph-based approach 27

Improving worker health and safety in wire arc additive manu...

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27th CIRP Life Cycle engineering Conference, LCE 2020

作者： Nagarajan, Hari P.N. Panicker, Suraj Mokhtarian, Hossein Coatanéa, Eric Haapala, Karl R. Faculty of Engineering and Natural Sciences Automation Technology and Mechanical Engineering Unit Tampere University Tampere33720 Finland School of Mechanical Industrial and Manufacturing Engineering Oregon State University CorvallisOR97331 United States

Research on human health and safety impacts of wire arc additive manufacturing is often overshadowed by the need for weld quality and mechanical strength improvements. To address this gap, a review of research literature is conducted focusing on the influence of welding process parameters, welding fumes, and fume exposure on worker health. The review uses a causal graph to classify research literature into two domains: manufacturing technology and public health. The graph serves as a precursor to development of a Bayesian network model, whose expected benefits, steps for implementation, and likely challenges that would be encountered during implementation are discussed. © 2020 The Author(s). Published by Elsevier B.V.

关键词： Bayesian networks

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