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arXiv 2022年

作者： Yang, Jing Fan Berrueta, Thomas A. Brooks, Allan M. Liu, Albert Tianxiang Zhang, Ge Gonzalez-Medrano, David Yang, Sungyun Koman, Volodymyr B. Chvykov, Pavel LeMar, Lexy N. Miskin, Marc Z. Murphey, Todd D. Strano, Michael S. Department of Chemical Engineering Massachusetts Institute of Technology CambridgeMA United States Center for Robotics and Biosystems Northwestern University EvanstonIL United States Department of Chemical Engineering University of Michigan Ann ArborMI United States Department of Electrical and Systems Engineering University of Pennsylvania PhiladelphiaPA United States Physics of Living Systems Massachusetts Institute of Technology CambridgeMA United States

Spontaneous oscillations on the order of several hertz are the drivers of many crucial processes in nature. From bacterial swimming to mammal gaits, converting static energy inputs into slowly oscillating power is key to the autonomy of organisms across scales. However, the fabrication of slow micrometre-scale oscillators remains a major roadblock towards fully-autonomous microrobots. Here, we study a low-frequency oscillator that emerges from a collective of active microparticles at the air-liquid interface of a hydrogen peroxide drop. Their interactions transduce ambient chemical energy into periodic mechanical motion and on-board electrical currents. Surprisingly, these oscillations persist at larger ensemble sizes only when a particle with modified reactivity is added to intentionally break permutation symmetry. We explain such emergent order through the discovery of a thermodynamic mechanism for asymmetry-induced order. The onboard power harvested from the stabilized oscillations enables the use of electronic components, which we demonstrate by cyclically and synchronously driving a microrobotic arm. This work highlights a new strategy for achieving low-frequency oscillations at the microscale, paving the way for future microrobotic autonomy. © 2022, CC BY-NC-ND.

关键词： Mammals

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Constructive Barrier Feedback for Collision Avoidance in Leader-Follower Formation Control

Constructive Barrier Feedback for Collision Avoidance in Lea...

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IEEE Conference on Decision and Control

作者： Zhiqi Tang Rita Cunha Tarek Hamel Carlos Silvestre Institute for Systems and Robotics Instituto Superior Técnico Universidade de Lisboa Portugal I3S-CNRS Université Côte d'Azur and Institut Universitaire de France France Department of Electrical and Computer Engineering Faculty of Science and Technology University of Macau Macao China

This paper proposes a novel constructive barrier feedback for reactive collision avoidance between two agents. It incorporates this feature in a formation tracking control strategy for a group of 2nd-order dynamic robots defined in three-dimensional space. Using only relative measurements between neighboring agents, we propose an elegant decentralized controller as the sum of a nominal tracking controller and the constructive barrier feedback for leader-follower formations under a directed single-spanning tree graph topology. The key ingredient is the use of divergent flow as a dissipative term, which slows down the relative velocity in the direction of the neighboring robots without compromising the nominal controller's performance. Compared to traditional barrier function-based optimization controllers, the proposed constructive barrier feedback avoids feasibility issues and results in more computationally efficient control algorithms with systematic equilibrium analysis. Simulations are provided to validate the effectiveness of the proposed control method.

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Evaluation of Robustness Metrics for Defense of Machine Learning systems

Evaluation of Robustness Metrics for Defense of Machine Lear...

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International Conference on Military Communications and Information systems (ICMCIS)

作者： J. DeMarchi R. Rijken J. Melrose B. Madahar G. Fumera F. Roli E. Ledda M. Aktaş F. Kurth P. Baggenstoss B. Pelzer L. Kanestad Collaborative Engineering Systems & Aerospace Systems Information Supremacy Royal Netherlands Aerospace Centre NLR Amsterdam NLD Cyber & Information Systems Division Defence Science and Technology Laboratory Portondown GBR Department of Electrical and Electronic Engineering University of Cagliari Cagliari ITA Department of Informatics Bioengineering Robotics and Systems Engineering University of Genoa Genoa ITA Department of Computer Control and Management Engineering Sapienza University of Rome Rome ITA Defence Systems Technologies Division ASELSAN Ankara TUR Fraunhofer Institute for Communication Information Processing and Ergonomics Bonn DEU Swedish Defence Research Agency Cyber Defence and C2 Technology Division Stockholm SWE

In this paper we explore some of the potential applications of robustness criteria for machine learning (ML) systems by way of tangible “demonstrator” scenarios. In each demonstrator, ML robustness metrics are applied to real-world scenarios with military relevance, indicating how they might be used to help detect and handle possible adversarial attacks on ML systems. We conclude by sketching promising future avenues of research in order to: (1) help establish useful verification methodologies to facilitate ML robustness compliance assessment; (2) support development of ML accountability mechanisms; and (3) reliably detect, repel, and mitigate adversarial attack.

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Generic Properties of Koopman Eigenfunctions for Stable Fixed Points and Periodic Orbits ⁎ ⁎

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IFAC-PapersOnLine 2021年第9期54卷 267-272页

作者： Matthew D. Kvalheim David Hong Shai Revzen Department of Electrical and Systems Engineering University of Pennsylvania Philadelphia PA 19104 USA Department of Statistics University of Pennsylvania Philadelphia PA 19104 USA Department of Electrical Engineering and Computer Science Ecology and Evolutionary Biology Department Robotics Institute University of Michigan Ann Arbor MI 48109

Our recent work established existence and uniqueness results for C k (actually C k,α loc ) linearizing semiconjugacies for C flows defined on the entire basin of an attracting hyperbolic fixed point or periodic orbit (Kvalheim and Revzen, 2019). Applications include (i) improvements, such as uniqueness statements, for the Sternberg linearization and Floquet normal form theorems, and (ii) results concerning the existence, uniqueness, classification, and convergence of various quantities appearing in the “applied Koopmanism” literature, such as principal eigenfunctions, isostables, and Laplace averages. In this work we consider the broadness of applicability of these results with an emphasis on the Koopmanism applications. In particular we show that, for the flows of “typical” c ∞ vector fields having an attracting hyperbolic fixed point or periodic orbit with a fixed basin of attraction, the c ∞ Koopman eigenfunctions can be completely classified, generalizing a result known for analytic eigenfunctions of analytic systems.

关键词： Koopman operator eigenfunctions generic properties isostables periodic orbits

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MonoVisual3DFilter: 3D tomatoes' localisation with monocular cameras using histogram filters

arXiv

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arXiv 2023年

作者： Magalhães, Sandro Costa dos Santos, Filipe Neves Moreira, António Paulo Dias, Jorge Faculty of Engineering University of Porto Porto Portugal INESC TEC Instituto de Engenharia de Sistemas e Computadores Tecnologia e Ciência Porto Portugal Institute of Systems and Robotics Department of Electrical Engineering and Computers University of Coimbra Coimbra Portugal Khalifa University of Science Technology and Research Abu Dhabi United Arab Emirates

Performing tasks in agriculture, such as fruit monitoring or harvesting, requires perceiving the objects' spatial position. RGB-D cameras are limited under open-field environments due to lightning interferences. So, in this study, we state to answer the research question: "How can we use and control monocular sensors to perceive objects' position in the 3D task space?" Towards this aim, we approached histogram filters (Bayesian discrete filters) to estimate the position of tomatoes in the tomato plant through the algorithm MonoVisual3DFilter. Two kernel filters were studied: the square kernel and the Gaussian kernel. The implemented algorithm was essayed in simulation, with and without Gaussian noise and random noise, and in a testbed at laboratory conditions. The algorithm reported a mean absolute error lower than 10 mm in simulation and 20 mm in the testbed at laboratory conditions with an assessing distance of about 0.5 m. So, the results are viable for real environments and should be improved at closer distances. © 2023, CC BY-NC-ND.

关键词： Fruits

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Preliminary study of online real-time control system for lower extremity exoskeletons based on EEG and sEMG fusion

Preliminary study of online real-time control system for low...

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IEEE International Conference on robotics and Biomimetics

作者： Wenju Li Keyong Shao Chi Zhu Yue Ma Wujing Cao Meng Yin Lijun Yang Mingxiang Luo Xinyu Wu School of Electrical Engineering Information Northeast Petroleum University Daqing China Guangdong Provincial Key Lab of Robotics and Intelligent System Shenzhen Institute of Advanced Technology Chinese Academy of Sciences Shenzhen Guangdong China Department of Systems Life Engineering Maebashi Institute of Technology Meabashi Japan

ISBN: (纸本)9781665481106

Motion imaging (MI) is widely used in exoskele-ton robot control direction. However, online real-time con-trol of exoskeletons based on biological signals is difficult to achieve. Because the anti-interference of biological signals in real life is poor and affected by individual differences, the control of auxiliary equipment by the realization of human-machine interface is still facing great challenges. In this paper, a human-machine interface (HMI) based on hybrid biological signals is designed and online real-time control of lower extremity exoskeletons is realized. Based on a comprehensive analysis of human walking, the HMI uses the electromyography signals (upper extremities) and EEG signals generated during real exercise as input signals. Different analysis methods are designed for different modal signals. We extracted four features of sEMG signals to distinguish between different movement processes in the human body. For EEG signals, the use of Independent Component Analysis (ICA) increases the robustness of the system. Event-related desynchronization/synchronization (ERS/ERD) and power spectral densities are reused for analysis from the perspective of the interaction of multiple information in the channel, time and frequency domains. The human-machine interface integrates EEG and EMG multimodal biological signals, and the average recognition accuracy of different subjects has reached 93.7%. In order to increase the recognition accuracy of practical applications and reduce the differences between different individuals, a window voting mechanism is designed. Healthy subjects were tested, and the recognition accuracy of the lower limb exoskeleton online real-time assistance system reached 99%, with high accuracy and reliability.

关键词： Legged locomotion Exoskeletons Feature extraction Real-time systems Electroencephalography Biology Robustness

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Exploring workout repetition counting and validation through deep learning 17th

Exploring workout repetition counting and validation through...

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17th International Conference on Image Analysis and Recognition, ICIAR 2020

作者： Ferreira, Bruno Ferreira, Pedro M. Pinheiro, Gil Figueiredo, Nelson Carvalho, Filipe Menezes, Paulo Batista, Jorge Institute of Systems and Robotics Department of Electrical and Computer Engineering University of Coimbra Coimbra Portugal Nixfuste Nova Porto Portugal Prozis.Tech Maia Portugal

ISBN: (纸本)9783030503468

Studying human motion from images and videos has turned into an interesting topic of research given the recent advances in computer vision and deep learning algorithms. When focusing on the automatic procedure of tracking physical exercises, cameras can be used for full human pose estimation in relation to worn sensors. In this work, we propose a method for workout repetition counting and validation based on a set of skeleton-based and deep semantic features that are obtained from a 2D human pose estimation network. Given that some of the individuals’ body parts might be occluded throughout physical exercises, we also perform a multi-view analysis on supporting cameras to improve our recognition rates. Nevertheless, the obtained results for a single-view approach show that we are able to count valid repetitions with over 90% precision scores for 4 out of 5 considered exercises, while recognizing more than 50% of the invalid ones. © Springer Nature Switzerland AG 2020.

关键词： Cameras

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Coordinated Guiding Vector Field Design for Ordering-Flexible Multi-Robot Surface Navigation

arXiv

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arXiv 2024年

作者： Hu, Bin-Bin Zhang, Hai-Tao Yao, Weijia Sun, Zhiyong Cao, Ming The School of Artificial Intelligence and Automation The Engineering Research Center of Autonomous Intelligent Unmanned Systems The Key Laboratory of Image Processing and Intelligent Control The State Key Lab of Digital Manufacturing Equipment and Technology Huazhong University of Science and Technology Wuhan430074 China The School of Robotics Hunan University Hunan410082 China The Institute of Engineering and Technology University of Groningen Groningen9747 AG Netherlands Department of Electrical Engineering Eindhoven University of Technology Netherlands

We design a distributed coordinated guiding vector field (CGVF) for a group of robots to achieve ordering-flexible motion coordination while maneuvering on a desired two-dimensional (2D) surface. The CGVF is characterized by three terms, i.e., a convergence term to drive the robots to converge to the desired surface, a propagation term to provide a traversing direction for maneuvering on the desired surface, and a coordinated term to achieve the surface motion coordination with an arbitrary ordering of the robotic group. By setting the surface parameters as additional virtual coordinates, the proposed approach eliminates potential singularity of the CGVF and enables both the global convergence to the desired surface and the maneuvering on the surface from all possible initial conditions. The ordering-flexible surface motion coordination is realized by each robot to share with its neighbors only two virtual coordinates, i.e. that of a given target and that of its own, which reduces the communication and computation cost in multi-robot surface navigation. Finally, the effectiveness of the CGVF is substantiated by extensive numerical simulations. Copyright © 2024, The Authors. All rights reserved.

关键词： Navigation

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Myoelectric Prosthetic Hand with Adjustable Tightening Socket for Varied Residual Limb Shapes*

Myoelectric Prosthetic Hand with Adjustable Tightening Socke...

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IEEE International Conference on Cyborg and Bionic systems (CBS)

作者： Yuki Inoue Yuki Kuroda Yoshiko Yabuki Yusuke Yamanoi Xu Yong Xiaobei Jing Hiroshi Yokoi Department of Mechanical and Intelligent Engineering The University of Electro-Communications Chofu Tokyo JAPAN OMRON SINIC X Corporation Bunkyo-ku Tokyo JAPAN department of Electrical Engineering Faculty of Engineering Tokyo University of Science Katushika-ku Tokyo JAPAN CAS Key Laboratory of Human-Machine Intelligence-Synergy Systems Shenzhen Institute of Advanced Technology (SIAT) Chinese Academy of Sciences (CAS) and the SIAT Branch Shenzhen Institute of Artificial Intelligence and Robotics for Society Shenzhen CHINA Department of Mechanical and Intelligent Engineering Center for Neuroscience and Biomedical Engineering The University of Electro-Communications Chofu Tokyo JAPAN Mu-BORG K.K. Chofu JAPAN

ISBN: (数字)9798350388039

ISBN: (纸本)9798350388046

The prosthetic socket serves as an interface between the body and the machine. If the socket is not well-fitted to the residual limb, pain can occur. The shape of the residual limb changes over time as surgical scars stabilize or the patient’s body weight fluctuates. A socket with a cutout on the side can be tightened from the outside to adjust its circumference and accommodate these changes. However, when the circumference of the rigid socket is adjusted to fit, soft skin can become trapped due to friction between the skin and the socket. This phenomenon causes pain due to pinching. Consequently, this mechanism cannot be used for myoelectric prosthetic hands, where direct contact between the socket and the skin is necessary. In this study, we developed a socket with a variable circumference that suppresses skin pinching. We applied it to participants with different residual limb shapes. A Box and Block Test (BBT) was performed using two types of sockets. The first used a conventional socket designed to fit their residual limb shape. The second used the proposed socket, which was designed to fit the residual limb’s shape of one out of two participants and adapted to the residual limb’s changing shape. The results of the BBT showed not much difference in the number of blocks moved between the conventional socket and the proposed socket. Therefore, the performance of the proposed socket was comparable to that of conventional sockets and could be applied to different residual limbs. In other words, the proposed socket was shown to adapt to changes in the residual limb without causing pain. Sockets with the proposed functionality could be used in a variety of bio-interfaces, allowing for flexible connections between the body and machines.

关键词： Limbs Shape Pain Sockets Human-machine systems Friction Surgery Skin Interviews Prosthetic hand

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Enhancing value creation in Energy Communities through flexibility management and network ancillary services provision

Enhancing value creation in Energy Communities through flexi...

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2022 ECEEE Summer Study on Energy Efficiency: Agents of Change

作者： Patrão, Carlos Matos, Luisa Landeck, Jorge Klein, Lurian Mendes, Gonçalo da Silva, Nuno Pinho Fulgêncio, Nuno O'Callaghan, Tim Stevens, Peter Institute of Systems and Robotics and Cleanwatts Dep. of Electrical and Computer Engineering University of Coimbra Portugal Cleanwatts Coimbra Portugal University of Coimbra and Cleanwatts LIBPhys Department of Physics University of Coimbra Portugal Lappeenranta-Lahti University of Technology LUT Finland R&D Nester Centro de Investigação em Energia REN Sacavém Portugal Electric Corby Corby Enterprise Centre England United Kingdom

ISBN: (纸本)9789198827002

The Clean Energy for all Europeans policy package has opened the way for a major transition of the European energy landscape towards customer empowerment and local energy markets development. The European Green Deal, the Fit for 55 % package and the European Directives revision are pushing forward Renewable Energy Communities, which will disrupt the energy sector and overcome limitations of existing rigid energy markets. The rise of distributed energy technologies is fostering the development of customer-centered services such as peer-to-peer energy trading. However, adequate tools and business models to interface and engage with energy markets are still lacking. The H2020 FleXunity project is addressing the emerging market needs by developing a technological platform, that combines advanced artificial intelligence algorithms, blockchain technology and demand response services, to exploit new business models that could value the aggregation of small-scale energy assets. Although the concept of these platforms is relatively well known, their real-world implementation and validation is still at an early stage. This paper presents the FleXunity project's main objectives, details of the Virtual Power Plant managing Platform under development and the characteristics of two distinct real world pilot Energy Communities already deployed in the UK and Iberia. It also presents an analysis of the role that Demand Response activities and independent aggregation could play in Energy Communities, and specifically explores the role of Demand Response in the balancing markets of Finland, UK, Spain, and Portugal. Focusing on the pilot markets, the project also identifies the most promising balancing services to be provided by Energy Communities, by surveying and framing the existing regulatory qualification requirements. © 2022 European Council for an Energy Efficient Economy. All rights reserved.

关键词： Smart power grids

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