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International Conference on Intelligent Transportation

作者： Tiago Barros Luís Garrote Martin Aleksandrov Cristiano Premebida Urbano J. Nunes Department of Electrical and Computer Engineering University of Coimbra Institute of Systems and Robotics Portugal Dahlem Center for Machine Learning and Robotics Freie Universität Berlin Berlin

Autonomous driving systems often require reliable loop closure detection to guarantee reduced localization drift. Recently, 3D LiDAR-based localization methods have used retrieval-based place recognition to find revisited places efficiently. However, when deployed in challenging real-world scenarios, the place recognition models become more complex, which comes at the cost of high computational demand. This work tackles this problem from an information-retrieval perspective, adopting a first-retrieve-then-re-ranking paradigm, where an initial loop candidate ranking, generated from a 3D place recognition model, is re-ordered by a proposed lightweight transformer-based re-ranking approach (TReR). The proposed approach relies on global descriptors only, being agnostic to the place recognition model. The experimental evaluation, conducted on the KITTI Odometry dataset, where we compared TReR with s.o.t.a. re-ranking approaches such as αQE and SGV, indicate the robustness and efficiency when compared to αQE while offering a good trade-off between robustness and efficiency when compared to SGV.

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Automation of Humanitarian Demining: The 2016 Humanitarian robotics and Automation Technology Challenge

Automation of Humanitarian Demining: The 2016 Humanitarian R...

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International Conference on robotics and Automation for Humanitarian Applications

作者： Lino Marques Edson Prestes Sedat Dogru Jose Prado Joao Pedro Macedo Renata Neuland Mathias Mantelli Renan Maffei Raj Madhavan Institute of Systems and Robotics Department of Electrical and Computer Engineering University of Coimbra Informatics Institute Federal University of Rio Grande do Sul Humanitarian Robotics Technologies (HRT) LLC

ISBN: (纸本)9781509052042

This paper introduces the problem of detection of landmines and unexploded ordnances. This is a serious humanitarian problem affecting dozens of countries across the world. A solution using robots for cleaning affected areas would have a huge positive impact for the life of persons living there and has for long been foreseen, but this approach has its own difficulties. The paper presents a Challenge aiming to engage researchers across the world into this problem and helping to improve robotics demining. The different phases of the Humanitarian robotics and Automation Technology Challenge (HRATC) are described and the progresses achieved after three years of running the Challenge are analyzed and discussed.

关键词： robotics and automation Automation Humanitarian demining ANTITANK MINES robotics Robot Developing Countries Persons Demining

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An Outdoor Guidepath Navigation System for AMRs Based on Robust Detection of Magnetic Markers

An Outdoor Guidepath Navigation System for AMRs Based on Rob...

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12th IEEE International Conference on Emerging Technologies and Factory Automation (ETFA 2007), vol.2

作者： Ana C. Lopes Fernando Moita Urbano Nunes Razvan Solea ISR-Institute of Systems and Robotics Department of Electrical and Computer Engineering University of Coimbra Coimbra Portugal

This paper presents an outdoor guidepath navigation system for autonomous mobile robots (AMR) that use permanent magnetic markers embedded in the ground. The odometric data provided by the wheel encoders is fused with the data from magnetic markers. The extended Kalman filter (EKF) was chosen for the fusion process. The AMR is equipped with a magnetic sensing ruler (MSR) developed at isr-UC that is able to perform a robust detection of magnetic markers. The detection is based on a 3-D algorithm that includes longitudinal-fitting detection (LFD), and cross-fitting detection (CFD). Both, the LFD and the CFD are based on the least squares fitting (LSF) of the measurement data with the 3-D model of the vertical magnetic field. The experimental results with Robchair (intelligent wheelchair being developed at isr-UC) primarily show that the detection system is robust, since it is able to detect true magnetic markers, and to eliminate noisy magnetic distortions and false markers. The design, and implementation of the navigation algorithm in the Robchair were carried out, and results are presented.

关键词： Navigation Robustness Magnetic separation Computational fluid dynamics Magnetic field measurement Mobile robots Wheels Least squares methods Distortion measurement Wheelchairs

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Electric Vehicle Physical Parameters Identification 48

Electric Vehicle Physical Parameters Identification

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48th Annual Conference of the IEEE Industrial Electronics Society, IECON 2022

作者： Maia, Ricardo Mendes, Jerome Araujo, Rui University of Coimbra Institute of Systems and Robotics Department of Electrical and Computer Engineering Pólo II CoimbraPT-3030-290 Portugal Critical Software S.A. Pq. Ind. de Taveiro Lt 49 CoimbraPT-3045-504 Portugal

ISBN: (数字)9781665480253

ISBN: (纸本)9781665480253

Electric vehicle physical parameters highly influence the modeling of its different systems. Although a simulation using data acquired from field tests can have satisfactory results, the parameters inaccuracy, due to either insufficient information or wear, can prevent a better performance. In this paper, 10 electric vehicle physical parameters are adjusted/calibrated by three metaheuristic algorithms: Particle Swarm Optimization, Genetic Algorithms, and Simulated Annealing. Moreover, tests on real short and long distance data sets were used in order to validate the proposed framework to EV model calibration. The results achieved indicate that parameter calibration is effective in the reduction of the modeling error. © 2022 IEEE.

关键词： Simulated annealing

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Mobile Robot Localization with Reinforcement Learning Map Update Decision aided by an Absolute Indoor Positioning System

Mobile Robot Localization with Reinforcement Learning Map Up...

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2019 IEEE/RSJ International Conference on Intelligent Robots and systems (IROS)

作者： Luís Garrote Miguel Torres Tiago Barros João Perdiz Cristiano Premebida Urbano J. Nunes Institute of Systems and Robotics Department of Electrical and Computer Engineering University of Coimbra Portugal Dept. of Aeronautical and Automotive Engineering Loughborough University UK

This paper introduces a new mobile robot localization solution consisting of two main modules: a Particle-Filter based Localization (PFL) and a Reinforcement-Learning based map updating, integrating relative measurements and absolute indoor positioning sensor (A-IPS) data. Concerning localization using 2D-LiDARs, featureless areas are known to be problematic. To solve this problem a classic PFL approach was modified to incorporate A-IPS position measurements in the prediction and update stages. The localization approach has the particularity of including the possibility of updating the map whenever major modifications are detected in the environment in relation to the current localization map. Due to the random sampling-based nature of the PFL, an associated map update solution is not trivial since small inconsistencies in the estimated pose can lead to erroneous map associations. The proposed method learns to decide by assigning higher rewards the greater is the overlap between the map and the 2DLIDAR scans, via RL, and then a proper update of the map is achieved. Validation of the proposed pipeline was carried out in a differential drive platform with algorithms developed in ROS. Tests were performed in two scenarios in order to assess the performance of both the localization module and the map update stage. The results show that the proposed localization method offers improvements in relation to known approaches, and consequently suggest promising perspectives for the proposed map update decision framework.

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Experimental validation of a nonlinear quadrotor controller with wind disturbance rejection

Experimental validation of a nonlinear quadrotor controller ...

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European Control Conference

作者： David Cabecinhas Rita Cunha Carlos Silvestre Department of Electrical Engineering and Computer Science and Institute for Robotics and Systems in Engineering and Science (LARSyS) Instituto Superior Tecnico Universidade Tecnica de Lisboa

ISBN: (纸本)9781479901890

This paper addresses the problem of designing and experimentally validating a controller for steering a quadrotor vehicle along a trajectory, while rejecting wind disturbances. The proposed solution consists of a nonlinear adaptive state feedback controller for thrust and torque actuation that asymptotically stabilizes the closed-loop system in the presence of constant force disturbances, used to model the wind action, and ensures that the actuation does not grow unbounded as a function of the position errors. A prototyping and testing architecture, developed to streamline the implementation and the tuning of the controller, is also described. Experimental results are presented to demonstrate the performance and robustness of the proposed controller.

关键词： Controllers Induction loop systems Activation location error state feedback controller Disturbance rejection Closed loop systems thrust Wind tuning trajectory asymptotic wind action nonlinearity

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AUV dynamics: Modelling and parameter estimation using analytical, semi-empirical, and CFD methods

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IFAC Proceedings Volumes 2004年第10期37卷 369-376页

作者： E.A. de Barros A. Pascoal E. de Sa Department of Mechatronics Engineering and Mechanical Systems University of São Paulo São Paulo SP. Brazil Institute for Systems and Robotics (ISR) and Dept. Electrical Engineering and Computers Instituto Superior Técnico Lisbon Portugal. National Institute of Oceanography Dona Paula Goa India

The paper addresses the problem of autonomous underwater vehicle (AUV) modeling and parameter estimation as a means to predict the expected dynamic performance of underwater vehicles and thus provide solid guidelines during their design phase. The use of analytical and semi-empirical (ASE) methods to predict the hydrodynamic derivatives of a large class of AUVs with conventional, streamlined bodies is discussed. An application is made to the estimation of the hydrodynamic derivatives of the MAYA AUV, an autonomous vehicle that is being developed under a joint Indian-Portuguese project. The estimates are used to predict the behavior of the vehicle in the vertical plane and to assess the impact of stern plane size on its expected performance.

关键词： Autonomous Underwater Vehicles AUV Modeling Parameter Estimation Computational Fluid Dynamics

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BioImplantable bone stress sensor

BioImplantable bone stress sensor

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2005 27th Annual International Conference of the engineering in Medicine and Biology Society, IEEE-EMBS 2005

作者： Fernando Alfaro, J. Weiss, Lee E. Campbell, Phil G. Miller, Mark C. Heyward, Christa Doctor, John S. Fedder, Gary K. Robotics Institute Carnegie Mellon University Pittsburgh PA 15213 Department of Electrical and Computer Engineering Carnegie Mellon University Pittsburgh PA 15213 Institute for Complex Engineered Systems Department of Biomedical Engineering Carnegie Mellon University Pittsburgh PA 15213 School of Health Sciences Duquesne University Pittsburgh PA 15282 Department of Biological Sciences Duquesne University Pittsburgh PA 15282

ISBN: (纸本)0780387406

The clinical management of skeletal trauma and disease relies on radiographic imaging to infer bone quality. However, bone strength does not necessarily correlate well with image intensity. There is a need for a safe and convenient way to measure bone strength in situ. This paper presents a new technique to directly measure bone strength in situ at a micro-level scale through a MicroElectroMechanical System (MEMS) sensor. The proposed MEMS stress sensor comprises an array of piezoresistive sensor "pixels" to detect stress across the interfacial area between the MEMS chip and bone with resolution to 100 Pa, in 1 sec averaging. The sensors are located within a textured surface to accommodate sensor integration into bone. From initial research, surface topography with 30-60 μm features was found to be conducive to guiding new cell growth. Finite element analysis has led to a sensor design for normal and shear stress detection. © 2005 IEEE.

关键词： Biosensors

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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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Distributed state estimation for linear multi-agent systems with time-varying measurement topology

Distributed state estimation for linear multi-agent systems ...

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作者： Viegas, Daniel Batista, Pedro Oliveira, Paulo Silvestre, Carlos Philip Chen, C.L. Institute for Systems and Robotics Instituto Superior Técnico Av. Rovisco Pais Lisboa1049-001 Portugal Department of Mechanical Engineering Instituto Superior Técnico Universidade de Lisboa Lisboa Portugal Department of Electrical and Computer Engineering Faculty of Science and Technology University of Macau Taipa China Department of Computer and Information Science Faculty of Science and Technology University of Macau Taipa China

This paper addresses the problem of distributed state estimation in formations of vehicles with time-varying measurement topology. One or more vehicles have access to measurements of their own state, while the rest must rely on measurements relative to other vehicles in the vicinity and limited communication to estimate their own state, and it is assumed that the vehicles may gain or lose access to some measurements over time. The proposed solution consists in the implementation of a local state observer on-board each vehicle, and the effects of changes in the measurement topology on the estimation error dynamics are studied resorting to switched systems theory. Sufficient conditions for exponential stability of the global estimation error dynamics are presented for two different switching laws. The results are applied to the practical case of a formation of Autonomous Underwater Vehicles (AUVs), and simulation results are presented that validate the proposed solution. © 2015 Elsevier Ltd.

关键词： Multi agent systems

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