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2017 World Congress on engineering, WCE 2017

作者： Mendes, Mateus Coimbra, A. Paulo Crisóstomo, Manuel M. ESTGOH Polytechnic Institute of Coimbra Portugal ISR - Institute of Systems and Robotics Dept. of Electrical and Computer Engineering University of Coimbra Portugal

ISBN: (纸本)9789881404749

Recent advances in understanding the source of intelligent behaviour show that it is strongly supported on the use of a large and sophisticated memory. Constant increase of processing power and constant cost decrease of computer memory have encouraged research in vision-based methods for robot navigation. The present approach uses images stored into a Sparse Distributed Memory, implemented in parallel in a Graphics Processing Unit, as a method for robot localization and navigation. Algorithms for following previously learnt paths using visual and odometric information are described. A stack-based method for avoiding random obstacles, using visual information, is proposed. The results show the algorithms are adequate for indoors robot localization and navigation.

关键词： Graphics processing unit

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Comparison of different cooling fan designs for electric motors

Comparison of different cooling fan designs for electric mot...

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2017 IEEE International Electric Machines and Drives Conference, IEMDC 2017

作者： Roffi, Michele Ferreira, Fernando J. T. E. De Almeida, Anibal T. Institute of Systems and Robotics Department of Electrical and Computer Engineering University of Coimbra Portugal

ISBN: (纸本)9781509042814

Worldwide electric motor market is moving towards Premium/IE3, Super-Premium/IE4 and Ultra-Premium/IE5 efficiency classes. Therefore, motor manufacturers are constantly improving the overall design of three-phase asynchronous and synchronous motors and all the details with impact in the losses count, even if, individually, they just lead to efficiency gains of a fraction of a percentage point. In industry, most of the self-ventilated motors are driving unidirectional applications, such as fans, pumps, and compressors, and, therefore, the replacement of the typical bidirectional centrifugal fans of the external cooling system with a unidirectional axial fan may lead to a decrease in the acoustic noise and to a gain in the overall motor efficiency. In this paper, numerical simulations and experimental tests of different designs of axial fans and the respective comparison with the traditional centrifugal fans are presented. The tested axial fan prototypes were printed in plastic using a 3D printer. One of the novel axial fan designs led to a slight gain in the motor efficiency, maintaining the same operating temperature. That axial fan can be further optimized in order to require less power, have a better dynamic airflow, and produce less acoustic noise. © 2017 IEEE.

关键词： Energy efficiency

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CrowdWatcher: an open-source platform to catch the eye of the crowd

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Quality and User Experience 2019年第1期4卷 1-17页

作者： Lebreton, Pierre Hupont, Isabelle Hirth, Matthias Mäki, Toni Skodras, Evangelos Schubert, Anton Raake, Alexander Group of Networked Sensing and Control (NeSC) Zhejiang University Hangzhou China Institute of Intelligent Systems and Robotics Sorbonne University Paris France User-Centric Analysis of Multimedia Data Group Technische Universität Ilmenau Ilmenau Germany Department of Computer Science Aalto University Espoo Finland Department of Electrical and Computer Engineering University of Patras Patras Greece Audio Visual Technology Group Technische Universität Ilmenau Ilmenau Germany

This paper presents the open-source eye tracking platform CrowdWatcher. It enables researchers to measure gaze location and user engagement in a crowdsourcing context through traditional RGB webcams. The proposed platform particularly advances the field of Quality of Experience (QoE) research, as it allows the experimenter to collect remotely and with very limited effort novel information from crowds of participants, such as their commitment towards a task, attention and decision-making processes. Two different experiments are described that were conducted to demonstrate the platform’s potential. The first experiment addresses the measurement of participants’ behavior while performing a movie selection task. Results show that the platform provides complementary information to traditional self-reported data by taking gaze analysis into account. This is of particular relevance, since in a crowdsourcing context decision processes and attention are difficult to assess, and there is often limited control over the engagement of the test user with the task. A second experiment is conducted in the scenario of a multimedia QoE test. Prediction accuracy is compared to a professional infrared eye tracker. While CrowdWatcher performs less well than the professional eye tracker, it is still able to collect valuable gaze information in the far more challenging environment of crowdsourcing. As an outlook to further application domains, the usage of the platform to measure user engagement allows participants who do not pay attention to the task to be identified.

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Outer-linearization-based optimization algorithm for decentralized control design in flexure-linked H-gantry

Outer-linearization-based optimization algorithm for decentr...

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2018 IEEE/ASME International Conference on Advanced Intelligent Mechatronics, AIM 2018

作者： Ma, Jun Chen, Si-Lu Liang, Wenyu Li, Xiaocong Teo, Chek Sing Tay, Arthur Mamun, Abdullah Al Tan, Kok Kiong SIMTech-NUS Joint Lab. on Precision Motion Systems Department of Electrical and Computer Engineering National University of Singapore Singapore117582 Singapore Department of Electrical and Computer Engineering National Universit of Singapore Singapore117583 Singapore Mechatronics Group Singapore Institute of Manufacturing Technology Singapore138634 Singapore Zhejiang Provincial Key Laboratory of Robotics and Intelligent Manufacturing Equipment Technology Ningbo Institute of Industrial Technology Chinese Academy of Sciences Ningbo Zhejiang315121 China

ISBN: (纸本)9781538618547

The dual-drive H-gantry (DHG) is widely used for high-speed high-precision Cartesian motion control applications. Compared with the rigid-linked gantry design, the flexure-linked design is able to prevent the damage of the cross-arm because a small degree of rotation angle is allowed. Nevertheless, the flexure-linked design possibly induces the resonance of the gantry because of the chattering of control signals. To maintain the precision tracking of two carriages and minimize the chattering of control efforts, we aim to seek the most suitable flexure joints among the available ones and optimize the decentralized feedback controller parameters under parametric uncertainties. The mechatronic design problem is formulated as an H2 guaranteed cost control problem. All the stabilizing feedback controller gains are parameterized over a convex set, from here, numerical procedures are developed to obtain the global optimum by means of an outer-linearization-based optimization algorithm. Experiments are carried out and the results successfully validate the optimality and the robustness of the proposed design approach. © 2018 IEEE.

关键词： Feedback control

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Decentralized controller design in flexure-linked gantry by H2 guaranteed cost optimization approach 18

Decentralized controller design in flexure-linked gantry by ...

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18th International Conference of the European Society for Precision engineering and Nanotechnology, EUSPEN 2018

作者： Ma, Jun Chen, Si-Lu Liang, Wenyu Teo, Chek Sing Tay, Arthur Al Mamun, Abdullah Tan, Kok Kiong SIMTech-NUS Joint Lab. on Precision Motion Systems Department of Electrical and Computer Engineering National University of Singapore Singapore117582 Singapore Department of Electrical and Computer Engineering National University of Singapore Singapore117583 Singapore Agency for Science Technology and Research Singapore Institute of Manufacturing Technology Singapore138634 Singapore Zhejiang Provincial Key Laboratory of Robotics and Intelligent Manufacturing Equipment Technology Ningbo Institute of Industrial Technology Chinese Academy of Sciences Ningbo Zhejiang315201 China

ISBN: (纸本)9780995775121

Dual-drive H-gantry is widely used in many industrial processes that require high-speed and high-precision Cartesian motion. Unlike the rigid-linked gantry design, the flexure-linked design is able to prevent the damage of the cross-arm because a small degree of rotation angle is possible. However, the flexure-linked design may induce the resonant modes of the gantry because of high frequency control signals. To maintain the precision tracking of two carriages and minimize the chattering of control efforts, we aim to seek the most suitable flexure joints among the available ones while optimizing the decentralized feedback controller parameters under model uncertainties. In this way, good tracking performance is achieved without costly system re-design. In this work, we formulate the mechatronic design problem as an H2 guaranteed cost control problem. All the stabilizing feedback controller gains are parameterized over a convex set, and the global optimum is obtained by means of an outer-linearization-based algorithm. Experiments are conducted and the results successfully validate the effectiveness of the proposed design approach. © 2018 CURRAN-CONFERENCE. All rights reserved.

关键词： Convex optimization Dual-drive H-gantry Flexure Mechatronic design Optimal control Parallel mechanism

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Pull message passing for nonparametric belief propagation

arXiv

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arXiv 2018年

作者： Desingh, Karthik Opipari, Anthony Jenkins, Odest Chadwicke Laboratory for Perception RObotics Grounded REasoning SystemS Department of Electrical Engineering and Computer Science Robotics Institute University of Michigan Ann ArborMI48105 United States

We present a "pull" approach to approximate products of Gaussian mixtures within message updates for Nonparametric Belief Propagation (NBP) inference. Existing NBP methods often represent messages between continuous-valued latent variables as Gaussian mixture models. To avoid computational intractability in loopy graphs, NBP necessitates an approximation of the product of such mixtures. Sampling-based product approximations have shown effectiveness for NBP inference. However, such approximations used within the traditional "push" message update procedures quickly become computationally prohibitive for multi-modal distributions over high-dimensional variables. In contrast, we propose a "pull" method, as the Pull Message Passing for Nonparametric Belief propagation (PMPNBP) algorithm, and demonstrate its viability for efficient inference. We report results using an experiment from an existing NBP method, PAMPAS, for inferring the pose of an articulated structure in clutter. Results from this illustrative problem found PMPNBP has a greater ability to efficiently scale the number of components in its mixtures and, consequently, improve inference accuracy. Copyright © 2018, The Authors. All rights reserved.

关键词： Message passing

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Single-phasing protection of line-operated motors of different efficiency classes 53

Single-phasing protection of line-operated motors of differe...

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53rd IEEE/IAS Industrial and Commercial Power systems Technical Conference, I and CPS 2017

作者： Ferreira, Au Silva, Au De Almeida, Au Institute of Systems and Robotics Department of Electrical and Computer Engineering University of Coimbra Polo II Portugal

ISBN: (纸本)9781509057245

Single-phasing is one of the major causes of motor failure in the industry. The electric motor market is changing fast due to the minimum energy performance standards. In a large number of cases, particularly when the original old motors are retrofitted with motors of higher efficiency classes, the respective overload protection devices are not properly tuned/configured or upgraded/replaced. In this paper, an overview of the motor protective devices and the main results of an experimental study on the behavior of five three-phase 7.5-kW, 400-V, 50-Hz, 4-pole motors, namely, four squirrel-cage induction motors of IE1, IE2/EPAct, IE3/NEMA Premium and IE4 classes and one line-start permanent-magnet of IE4 class, under single-phasing supply at no-load, locked-rotor and part-load operation, are presented. On the basis of the obtained results, it can be concluded that, in general, modern commercial thermal overload relays or thermal-magnetic circuit-breakers are able to protect line-operated motors against single-phasing operation, tripping within a safe time window, as long as they have differential mode mechanism, their trip class is properly selected, and the current setting correctly adjusted as a function of the motor efficiency class, technology, service factor, load, rated power and rated current. © 2017 IEEE.

关键词： Magnetic circuits

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Robot Force Control on a Beating Heart

Robot Force Control on a Beating Heart

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作者： Cortesão, Rui Dominici, Michel Department of Electrical and Computer Engineering Institute of Systems and Robotics University of Coimbra Coimbra3030 Portugal Institute of Systems and Robotics University of Coimbra Coimbra3030 Portugal

Cardiac interventions have to deal with several difficulties, where heart motion is a major one. This paper addresses the heart motion compensation problem under contact, relying on robot force control techniques. A double active observer (AOB) architecture is proposed to tackle precise force control in the presence of heart motion. One AOB controls the desired interaction force, and the other one is responsible for compensating heart motion autonomously. Three-degrees of freedom (DOF) force tracking on top of a beating heart is presented, showing that with the proposed control architecture, it is possible to have force controlled interventions with root mean square errors below 0.56 N (based on raw data). The 4-DOF whole arm manipulator (WAM) from Barrett Technologies is the medical arm, while another 3-DOF robot carrying an ex vivo heart generates heart motion based on recorded biosignals. © 2017 IEEE.

关键词： Force control

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Shape reconstruction using a mobile robot for demining and UXO classification

Shape reconstruction using a mobile robot for demining and U...

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2017 IEEE International Conference on robotics and Automation, ICRA 2017

作者： Dogru, Sedat Marques, Lino Institute of Systems and Robotics Department of Electrical and Computer Engineering University of Coimbra Coimbra3030-290 Portugal

ISBN: (纸本)9781509046331

Metal detectors are widely used to detect and localize land mines, as well as metallic clutter that causes many false alarms. These false alarms are handled by manual inspection with a prodder or using extra features like size and depth as well as fusion with other sensors like ground penetrating radar or chemical sensors. Directly shape itself has never been used, mainly due to infeasibility of the results of the few existing studies, which require controlled environments and dense sampling of the target objects. In this paper, we propose a new method for shape reconstruction that works with sparse data, and show its feasibility using field data collected by a mobile robot equipped with a commercial pulse induction metal detector carried by a custom 2DoF arm. This paper also describes the method employed to sweep natural terrains with the mobile manipulator and provides results of imaging a set of different metallic objects. © 2017 IEEE.

关键词： Mobile robots

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Forecasting intracranial hypertension using multi-scale waveform metrics

arXiv

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arXiv 2019年

作者： Hüser, Matthias Kündig, Adrian Karlen, Walter De Luca, Valeria Jaggi, Martin Biomedical Informatics Group Department of Computer Science ETH Zürich Universitätstrasse 6 Zürich8092 Switzerland Mobile Health Systems Lab Institute of Robotics and Intelligent Systems Department of Health Sciences and Technology ETH Zürich Zürich8008 Switzerland Department of Information Technology and Electrical Engineering ETH Zürich Zürich8092 Switzerland Machine Learning & Optimization Lab EPFL Lausanne1015 Switzerland

Objective: Acute intracranial hypertension is an important risk factor of secondary brain damage after traumatic brain injury. Hypertensive episodes are often diagnosed reactively, leading to late detection and lost time for intervention planning. A pro-active approach that predicts critical events several hours ahead of time could assist in directing attention to patients at risk. Approach: We developed a prediction framework that forecasts onsets of acute intracranial hypertension in the next 8 hours. It jointly uses cerebral auto-regulation indices, spectral energies and morphological pulse metrics to describe the neurological state of the patient. One-minute base windows were compressed by computing signal metrics, and then stored in a multi-scale history, from which physiological features were derived. Main results: Our model predicted events up to 8 hours in advance with alarm recall rates of 90% at a precision of 30.3% in the MIMIC-III waveform database, improving upon two baselines from the literature. We found that features derived from high-frequency waveforms substantially improved the prediction performance over simple statistical summaries of low-frequency time serie1s, and each of the three feature classes contributed to the performance gain. The inclusion of long-term history up to 8 hours was especially important. Significance: Our results highlight the importance of information contained in high-frequency waveforms in the neurological intensive care unit. They could motivate future studies on pre-hypertensive patterns and the design of new alarm algorithms for critical events in the injured brain. Copyright © 2019, The Authors. All rights reserved.

关键词： Morphology

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