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2009 IEEE/RSJ International Conference on Intelligent Robots and systems

作者： Lixin Dong Xinyong Tao Li Zhang Xiaobin Zhang Bradley J. Nelson Department of Electrical & Computer Engineering Michigan State University East Lansing MI USA ETH Zurich Institute of Robotics and Intelligent Systems Zurich Switzerland College of Chemical Engineering and Materials Science Zhejiang University of Technology Hangzhou China Department of Materials Science and Engineering University of Zhejiang Hangzhou China

Modes of melting and evaporation of metal at attogram level from individual carbon nanotubes (CNTs) are investigated experimentally using nanorobotic manipulation inside a transmission electron microscope. We compared the melting and evaporation induced by electric current, Joule heating, charge, and ionization. Experiments show that the most effective method is by positively ionizing the encapsulated metal, therefore, an electrostatic field can be used to guide the flow. Applications and potential applications of mass transport and deposition in nanofluidic systems have been presented including self-welding, actuation, and storage.

关键词： Carbon nanotubes Copper Transmission electron microscopy Current Materials science and technology Probes Intelligent robots Resistance heating Thermal conductivity Ionization

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An efficient algorithm for extrinsic calibration between a 3D laser range finder and a stereo camera for surveillance

An efficient algorithm for extrinsic calibration between a 3...

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International Conference on Advanced robotics (ICAR)

作者： H. Aliakbarpour P. Nunez J. Prado K. Khoshhal J. Dias Dept. Electrical and Computer Engineering University of Coimbra Portugal Portugal ISIS Group Universidad de Málaga Spain Dept. Tecnología de los Computadores y las Comunicaciones Universidad de Extremadura Spain Institute of Systems and Robotics Department Electrical and Computer Engineering University of Coimbra Portugal

The combined use of 3D laser range finders (LRF) and cameras is increasingly common in the navigation application for autonomous mobile robots. The integration of laser range information and images requires the estimation of the Euclidean 3-dimensional transformation between the coordinate systems of the LRF and the cameras. This paper describes a new and efficient method to perform the extrinsic calibration between a 3D LRF and a stereo camera with the aid of inertial data. The main novelty of the proposed approach compared to other state of the art calibration procedures is the use of an inertial measurement unit (IMU), which decreases the number of points needed to a robust calibration. Furthermore, a freely moving bright spot is the only calibration object. A set of virtual 3D points is made by waving the bright spot through the working volume in three different planes. Its projections onto the images are found with sub-pixel precision and verified by a robust RANSAC analysis. These same points are extracted according to the laser scan data and are corresponded to the virtual 3D points in the stereo pair. Experimental results presented in this paper demonstrate the accuracy of our approach. Furthermore, the applicability of the proposed technique is high, only requiring of an inertial sensor coupled to the sensor platform. This approach has been also extended for a camera network.

关键词： Calibration Cameras Surveillance Robot vision systems Robustness Navigation Mobile robots Measurement units Image analysis Data mining

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Temporally and Spatially Deconflicted Path Planning for Multiple Autonomous Marine Vehicles

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IFAC Proceedings Volumes 2009年第18期42卷 376-381页

作者： Andreas J. Häusler Reza Ghabcheloo António M. Pascoal A. Pedro Aguiar Isaac I. Kaminer Vladimir N. Dobrokhodov Institute for Systems and Robotics Dept. of Electrical Engineering Instituto Superior Técnico Av. Rovisco Pais No. 1 1049-001 Lisboa Portugal Department of Intelligent Hydraulics and Automation Tampere Univ. of Technology P.O. Box 589 33101 Tampere Finland Department of Mechanical and Astronautical Engineering Naval Postgraduate School Monterey CA 93943 USA

There is currently a surge of interest in the development of advanced systems for cooperative control of multiple autonomous marine vehicles. Central to the implementation of these systems is the availability of efficient algorithms for multiple vehicle path planning that can take explicitly into account the capabilities of each vehicle and existing environmental conditions. Multiple vehicle path planning methods build necessarily on key concepts and algorithms for single vehicle path following. However, they go one step further in that they must explicitly address inter-vehicle collision avoidance, together with a number of criteria that may include simultaneous times of arrival at the assigned target points and energy minimization, to name but a few. As such, they pose considerable challenges both from a theoretical and practical implementation standpoint. This paper is a short overview of multiple vehicle path planning techniques. The exposition is focused on specific algorithms developed in the scope of research work in which the authors have participated. Namely, algorithms that ensure that at no time will two vehicles get closer in space than a desired safety distance, that is, achieve trajectory deconfliction. The algorithms make ample use of direct optimization methods that lead to efficient and fast techniques for path generation using a polynomial-based approach. The paper affords the reader a fast paced presentation of key algorithms that had their genesis in the aircraft field, discusses the results of simulations, and suggests problems that warrant further consideration.

关键词： Multiple Vehicle Missions Path Planning Spatial Deconfliction Temporal Deconfliction Autonomous Marine Vehicles

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Optimal design of vibration power generator for low frequency

Solid State Phenomena

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Solid State Phenomena 2009年 147-149卷 426-431页

作者： Hadas, Zdenek Singule, Vladislav Ondrusek, Cestmir Institute of Solid Mechanics Mechatronics and Biomechanics Faculty of Mechanical Engineering Brno University of Technology Technicka 2 Brno616 69 Czech Republic Institute of Production Machines Systems and Robotics Faculty of Mechanical Engineering Brno University of Technology Technicka 2 Brno616 69 Czech Republic Department of Power Electrical and Electronic Engineering Faculty of Electrical Engineering and Communication Brno University of Technology Technicka 8 Brno61669 Czech Republic

This paper deals with an optimal design of an electromagnetic energy harvesting generator for supplying wireless sensors with energy. The developed device is complex mechatronic system which generates an electrical power from an ambient low frequency mechanical vibration by use of a suitable electromagnetic generator. This device is excited by ambient mechanical vibration and electrical energy is harvested due to Faraday’s law. The design of this vibration power generator results from development cycles and the final generator can provide sufficient electrical energy for wireless sensors. The vibration power generator is tuned up to frequency of vibration 17 Hz and harvested output power depends non-linearly on level of vibration. The vibration power generator operates in level of vibration 0.1 – 1 G peak and output power is in range 2 – 25 mW. © (2009) Trans Tech Publications, Switzerland.

关键词： Energy harvesting

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Novelty detection and 3D shape retrieval based on Gaussian Mixture Models for autonomous surveillance robotics

Novelty detection and 3D shape retrieval based on Gaussian M...

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2009 IEEE/RSJ International Conference on Intelligent Robots and systems

作者： P. Núñez P. Drews R. Rocha M. Campos J. Dias ISIS Group Universidad de Málaga Spain Dept. Tecnologia de los Computadores y las Comunicaciones Universidad de Extremadura Spain Institute of Systems and Robotics Department Electrical and Computer Engineering University of Coimbra Portugal Dept. Computer Science Federal University of Minas Gerais Brazil Dept. Electrical and Computer Engineering University of Coimbra Portugal

This paper describes an efficient method for retrieving the 3-dimensional shape associated to novelties in the environment of an autonomous robot, which is equipped with a laser range finder. First, changes are detected over the point clouds using a combination of the Gaussian mixture model (GMM) and the earth mover's distance (EMD) algorithms. Next, the shape retrieval is achieved using two different algorithms. First, new samplings are generated from each Gaussian function, followed by a random sampling consensus (RANSAC) algorithm to retrieve geometric primitives. Furthermore, a new algorithm is developed to directly retrieve the shape according to the mathematical space of Gaussian mixture. In this paper, the set of geometric primitives has been limited to the set C = {sphere, cylinder, plane} . The two shape retrieval methods are compared in terms of computational cost and accuracy. Experimental results in various real and simulated scenarios demonstrate the feasibility of the approach.

关键词： Shape Surveillance Intelligent robots Mobile robots Simultaneous localization and mapping Clouds Sampling methods Navigation Robotic assembly Change detection algorithms

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Robotic wheelchair control considering user comfort - Modeling and experimental evaluation

Robotic wheelchair control considering user comfort - Modeli...

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ICINCO 2008 - 5th International Conference on Informatics in Control, Automation and robotics

作者： Solea, Razvan Nunes, Urbano ISR - Institute of Systems and Robotics Department of Electrical and Computer Engineering University of Coimbra 3030-290 Coimbra Portugal

ISBN: (纸本)9789898111319

This paper analyzes the comfort of wheelchair users when a sliding-mode trajectory-tracking controller is used. The transmission of the horizontal (fore-and-aft) vibration to the head-neck complex (HNC) in the seated human body may cause unacceptable discomfort and motion sickness. A double-inverted pendulum model with two degrees of freedom is considered as a model for the HNC. The user comfort is examined not only in the time domain (using the fourth power vibration dose value), but also in the frequency domain (using the cross-spectral density method). For measuring the acceleration of the wheelchair, along the trajectory, an inertial measurement unit was used.

关键词： Sliding mode control

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Communications in Computer and Information Science: Preface

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Communications in Computer and Information Science 2009年 24 CCIS卷 VI页

作者： Ranchordas, AlpeshKumar Araújo, Hélder J. Pereira, João Madeiras Braz, José INSTICC Setúbal Portugal Institute for Systems and Robotics Department of Electrical and Computer Engineering Polo II University of Coimbra Coimbra Portugal Departamento de Engenharia Informática Instituto Superior Técnico Lisboa Portugal Departamento de Sistemas e Informática Escola Superior de Tecnologia Do IPS Setúbal Portugal

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A General Framework for Multiple Vehicle Time-Coordinated Path Following Control

A General Framework for Multiple Vehicle Time-Coordinated Pa...

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2009 American Control Conference (ACC 2009)

作者： Reza Ghabcheloo Isaac Kaminer A. Pedro Aguiar Antonio Pascoal Department of Inteligent Hydraulics and Automation Tampere Univ of Technology P.O.Box 589 33101 Tampere Finland Department of Mechanical and Astronautical Engineering Naval Postgraduate School Monterey CA 93943 USA Dept. Electrical Engineering and Computers and the Institute for Systems and Robotics Instituto Superior Tecnico Av. Rovisco Pais 1 1049-001 Lisboa Portugal

ISBN: (纸本)9781424445233

This paper describes a general framework for the study of multiple vehicle, time-coordinated path following (TC-PF) control problems. An example is the situation where a group of vehicles is tasked to maneuver and arrive at pre-assigned final positions at the same time in a collision-free manner, while reducing some optimality criterion. The time of arrival is not fixed a priori, and the vehicles must negotiate their speeds along the spatial paths that they follow in order to arrive simultaneously and avoid collision. The general framework adopted leads to integrated solutions to TC-PF problems that unfold in three steps: 1) Generation of Deconflicted Trajectories for a group of vehicles, 2) Path Following for each vehicle along its assigned path, and 3) Coordination of the relative motion of the vehicles along their paths, so as to guarantee deconfliction and meet desired temporal constraints such as equal times of arrival. The last step is accomplished by varying the speed of each vehicle about the nominal speed profile computed in step 1, based on the exchange of information with its neighbors. The paper formulates the problem mathematically, offers a general framework for its solution, and illustrates the efficacy of the proposed methodology in simulation with dynamic models of Autonomous Underwater Vehicles (AUVs).

关键词： Marine vehicles Remotely operated vehicles robotics and automation Computational modeling Vehicle dynamics Mathematical model Underwater vehicles Scattering Oceans Sea surface

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Improving the generalization properties of neural networks: An application to vehicle detection

Improving the generalization properties of neural networks: ...

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11th International IEEE Conference on Intelligent Transportation systems, ITSC 2008

作者： Ludwig Jr., Oswaldo Nunes, Urbano ISR-Institute of Systems and Robotics Department of Electrical and Computer Engineering University of Coimbra Polo II 3030-290 Coimbra Portugal

ISBN: (纸本)9781424421121

In this paper a Multilayer Feedforward Neural Network based approach for vehicle detection is proposed. The main idea is to use such network to perform both feature extraction and classification. This simplicity enables real time applications. In order to achieve such capabilities, the network is trained by a new algorithm, proposed in this paper, named Minimization of Inter- Class Interference (MCI). Such algorithm aims to create a hidden space (i.e. feature space) where the patterns have a desirable statistical distribution. Regarding the neural architecture, the linear output layer is replaced by the Mahalanobis kernel, in order to improve generalization. Experiments are performed by means of a dataset that includes two standard datasets from Caltech car rear. Finally, disturbed images are used, in order to evaluate the robustness of the neural-network based vehicle detection. The proposed method reveals low miss rate, low false alarm rate and high area under ROC curve. In Matlab environment, the algorithm spends only 3.280e-4 seconds per image. These facts encourage this research line. © 2008 IEEE.

关键词： Feedforward neural networks

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A step toward autonomous pole climbing robots

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11th International Conference on Climbing and Walking Robots and the Support Technologies for Mobile Machines, CLAWAR 2008

作者： Tavakoli, Mahmoud Marjovi, Ali Marques, Lino De Almeida, Aníbal T. Institute for Systems Robotics Department of Electrical and Computer Engineering University of Coimbra 3030-290 Coimbra Portugal

ISBN: (纸本)9812835768

3D CLIMBER is a pole climbing robot which was developed at isr-UC. It can climb from 3D structures with bents and branches and scan whole area of the structure. Upon the completion of the mechanical structure some tests were conducted for proof of concept. During this test the errors which might happen were revealed and then a sensorial architecture were designed in order to measure the errors and a control architecture was proposed in order to compensate them. This paper discusses the source of errors and the approach for compensation of the errors and also the Mechatronics and the control architecture of the 3D CLIMBER. Copyright © 2008 by World Scientific Publishing Co. Pte. Ltd.

关键词： Errors

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