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IEEE Global Conference on Signal and Information Processing (GlobalSIP)

作者： João F. C. Mota João M. F. Xavier Pedro M. Q. Aguiar Markus Püschel Institute of Systems and Robotics Instituto Superior Técnico Technical University of Lisbon Portugal Department of Computer Science ETH Zurich Switzerland

Reconstructing compressed sensing signals involves solving an optimization problem. An example is Basis Pursuit (BP) [1], which is applicable only in noise-free scenarios. In noisy scenarios, either the Basis Pursuit Denoising (BPDN) [1] or the Noise-Aware BP (NABP) [2] can be used. Consider a distributed scenario where the dictionary matrix and the vector of observations are spread over the nodes of a network. We solve the following open problem: design distributed algorithms that solve BPDN with a column partition, i.e., when each node knows only some columns of the dictionary matrix, and that solve NABP with a row partition, i.e., when each node knows only some rows of the dictionary matrix and the corresponding observations. Our approach manipulates these problems so that a recent general-purpose algorithm for distributed optimization can be applied.

关键词： Dictionaries Distributed algorithms Vectors Compressed sensing Optimization Educational institutions Partitioning algorithms

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Experimental Validation of a Globally Stabilizing Feedback Controller for a Quadrotor Aircraft with Wind Disturbance Rejection

Experimental Validation of a Globally Stabilizing Feedback C...

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American 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 1049-001 Lisboa Portugal

ISBN: (纸本)9781479901777

This paper addresses the design and experimental evaluation of a globally stabilizing controller to steer a quadrotor vehicle along a predefined path. The proposed solution consists of a nonlinear adaptive state feedback controller for thrust and angular velocity actuation that i) guarantees convergence of the closed-loop path following error to zero in the presence of constant force disturbances and ii) ensures that the actuation does not grow unbounded as a function of the position error. A prototyping and testing architecture, developed to streamline the implementation and the tuning of the controller, is also described. Experimental results, where the quadrotor is subject to external wind disturbances, are presented to demonstrate the performance and robustness of the proposed controller.

关键词： Controllers feedback controller stabilizing feedback location error state feedback controller Disturbance rejection Wind tuning Aircraft follow error

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A new algorithm for linearization up to multi-output and multi-input injection for a class of systems with implicitly defined outputs

A new algorithm for linearization up to multi-output and mul...

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European Control Conference (ECC)

作者： Sérgio S. Rodrigues A. Pedro Aguiar Öaw Institute for Computational and Applied Mathematics (RICAM) Linz Austria Department of Electrical and Computer Engineering Laboratory of Robotics and Systems in Engineering and Science (LARSyS) Lisbon Portugal

ISBN: (纸本)9781479901890

Given a class of nonlinear systems with implicitly defined outputs, we provide a new algorithm to find appropriate local coordinates, in which the resulting system takes a desired target form that is state-affine, up to output and input injection. Once in the target form, it is possible to construct a state-space observer with linear, possibly time-varying, error dynamics.

关键词： Vectors Equations Observers Gold Geometry Nonlinear dynamical systems

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GES tightly coupled attitude estimation based on a LBL/USBL positioning system

GES tightly coupled attitude estimation based on a LBL/USBL ...

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European Control Conference (ECC)

作者： Pedro Batista Carlos Silvestre Paulo Oliveira Institute for Systems and Robotics Universidade Técnica de Lisboa Lisboa Portugal Department of Electrical and Computer Engineering Faculty of Science and Technology of the University of Macau.

ISBN: (纸本)9781479901890

Typical attitude estimation solutions for underwater vehicles rely on magnetometers, which are prone to magnetic field distortions. This can preclude its use in intervention scenarios, in the vicinity of objects with strong magnetic signatures, severely endangering not only the intervention mission but also the operation of the underwater vehicle. This paper presents a novel attitude estimation solution, based on a combined Long Baseline / Ultra Short Baseline (LBL/USBL) acoustic positioning system, with application to underwater vehicles. The range and range differences of arrival obtained with the LBL/USBL are directly embedded in the estimator dynamics, without any linearization whatsoever, and globally exponentially stable (GES) error dynamics are achieved. Simulation results evidence good performance of the proposed solution.

关键词： Observers Vehicles Acoustics Vehicle dynamics Vectors Magnetometers

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Darwinian Robotic Swarms for exploration with minimal communication

Darwinian Robotic Swarms for exploration with minimal commun...

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Congress on Evolutionary Computation

作者： Micael S. Couceiro Rui P. Rocha Nuno M. F. Ferreira Patricia A. Vargas Institute of Systems and Robotics University of Coimbra Coimbra Portugal Department of Electrical Engineering Engineering Institute of Coimbra Robo Corporation Coimbra Portugal Robotics Laboratory School of Mathematical and Computer Science Heriot-Watt University Edinburgh UK

ISBN: (纸本)9781479904532

The Robotic Darwinian Particle Swarm Optimization (RDPSO) recently introduced in the literature has the ability to dynamically partition the whole population of robots based on simple “punish-reward” rules. Although this evolutionary algorithm enables the reduction of the amount of required information exchange among robots, a further analysis on the communication complexity of the RDPSO needs to be carried out so as to evaluate its scalability. This paper analyses the architecture of the RDPSO communication system, thus describing the dynamics of the communication data packet structure shared between teammates. Moreover, a set of simple communication rules is also proposed in order to reduce the communication overhead within swarms of robots. Experimental results with teams of 15 real robots show that the proposed methodology reduces the communication overhead, thus improving the scalability and applicability of the RDPSO algorithm.

关键词： Robot kinematics Robot sensing systems Mobile ad hoc networks Complexity theory Spread spectrum communication Force

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Underwater Target Positioning with a Single Acoustic Sensor

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IFAC Proceedings Volumes 2013年第33期46卷 233-238页

作者： D. Moreno-Salinas A.M. Pascoal J. Aranda Department of Computer Science and Automatic Control National University Distance Education (UNED) Spain Laboratory of Robotics and Systems in Engineering and Science (LARSyS) Instituto Superior Tecnico (IST) University of Lisbon Portugal Adjunct Scientist National Institute of Oceanography (NIO) Goa India

The availability of reliable underwater positioning systems to localize one or more vehicles simultaneously based on information received on-board a support ship or an autonomous surface vessel is key to the operation of some classes of AUVs. Furthermore, there is considerable interest in reducing the number of sensors involved in acoustic navigation/positioning systems to reduce the costs involved and the time consumed in the deployment, callibration, and recovery phases. Motivated by these considerations, in this paper we address the problem of single underwater target positioning based on measurements of the ranges between the target and a moving sensor at the sea surface, obtained via acoustic ranging devices. In particular, and speaking in loose terms, we are interested in determining the optimal geometric trajectory of the surface sensor that will, in a well defined sense, maximize the range-related information available for underwater target positioning. To this effect, an appropriate Fisher Information Matrix is defined and its determinant is maximized to yield the sensor trajectory that maximizes the accuracy of the target position estimate that can possibly be obtained with any unbiased estimator. It is shown that the optimal trajectory depends on the relative velocity of the sensor, the sampling time between measurements, and the number of measurements acquired for the FIM computation. Simulation examples illustrate the key results derived.

关键词： Autonomous Vehicles Underwater Navigation Optimal Sensor Placement Positioning Fisher Information Matrix Cramer-Rao Bound

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Human-robotic collaborative intelligent control for reaching performance

Human-robotic collaborative intelligent control for reaching...

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7th International Conference on Foundations of Augmented Cognition, AC 2013, Held as Part of 15th International Conference on Human-computer Interaction, HCI International 2013

作者： Gentili, Rodolphe J. Oh, Hyuk Shuggi, Isabelle M. Goodman, Ronald N. Rietschel, Jeremy C. Hatfield, Bradley D. Reggia, James A. Department of Kinesiology Cognitive Motor Neuroscience Laboratory University of Maryland College Park MD 20742 United States Neuroscience and Cognitive Science Program University of Maryland College Park MD 20742 United States Maryland Robotics Center University of Maryland College Park MD 20742 United States Institute for Systems Research University of Maryland College Park MD 20742 United States Veterans Health Administration Maryland Exercise and Robotics Center of Excellence Baltimore MD 21201 United States Department of Computer Science University of Maryland College Park MD 20742 United States Maryland Institute for Advanced Computer Studies University of Maryland College Park MD 20742 United States

ISBN: (纸本)9783642394539

In most human-robot interfaces, the user completely controls the robot that operates as a passive tool without adaptation capabilities. However, a synergetic human-robot interface where both agents collaborate could improve the user's performance while reducing the cognitive and physical workload. Specifically, when considering this framework applied to rehabilitation, we examined a shared collaborative control between a human user and an adaptive biologically inspired neurocontroller in order to perform reaching movements with a simulated prosthetic arm. When this neurocontroller was enabled, it progressively learned from the user to control the prosthetic arm, increasing its role in the shared performance and facilitating the user's reaching movements. This resulted in the user's performance enhancement and in a reduction of his/her cognitive workload. The long term goal of this work is to contribute to the development of the next generation of intelligent human-robotic interfaces for rehabilitation. © 2013 Springer-Verlag Berlin Heidelberg.

关键词： Adaptive control systems

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An Investigation on the Accuracy of Regional Ocean Models Through Field Trials

An Investigation on the Accuracy of Regional Ocean Models Th...

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IEEE International Conference on robotics and Automation

作者： Ryan N. Smith Kimia Nazarzadeh Jonathan Kelly Gaurav S. Sukhatme School of Electrical Engineering and Computer Science Queensland University of Technology Brisbane QLD 4001 Australia. Robust Robotics Group Computer Science and Artificial Intelligence Laboratory Massachusetts Institute of Technology Cambridge MA 02142 USA. Robotic Embedded Systems Laboratory Department of Computer Science University of Southern California Los Angeles CA 90089 USA.

ISBN: (纸本)9781467356404

Recent efforts in mission planning for underwater vehicles have utilised predictive models to aid in navigation, optimal path planning and drive opportunistic sampling. Although these models provide information at a unprecedented resolutions and have proven to increase accuracy and effectiveness in multiple campaigns, most are deterministic in nature. Thus, predictions cannot be incorporated into probabilistic planning frameworks, nor do they provide any metric on the variance or confidence of the output variables. In this paper, we provide an initial investigation into determining the confidence of ocean model predictions based on the results of multiple field deployments of two autonomous underwater vehicles. For multiple missions of two autonomous gliders conducted over a two-month period in 2011, we compare actual vehicle executions to simulations of the same missions through the Regional Ocean Modeling System in an ocean region off the coast of southern California. This comparison provides a qualitative analysis of the current velocity predictions for areas within the selected deployment region. Ultimately, we present a spatial heat-map of the correlation between the ocean model predictions and the actual mission executions. Knowing where the model provides unreliable predictions can be incorporated into planners to increase the utility and application of the deterministic estimations.

关键词： Regional Ocean Models Through Field Trials mission planning underwater vehicles

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Sensor-based Globally Asymptotically Stable Range-Only Simultaneous Localization and Mapping

Sensor-based Globally Asymptotically Stable Range-Only Simul...

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IEEE Annual Conference on Decision and Control

作者： Pedro Lourenco Pedro Batista Paulo Oliveira Carlos Silvestre C. L. Philip Chen Institute for Systems and Robotics Instituto Superior Tecnico Universidade de Lisboa Av. Rovisco Pais 1049-001 Lisboa Portugal Department of Electrical and Computer Engineering Faculty of Science and Technology of the University of Macau

ISBN: (纸本)9781467357159

Range-only simultaneous localization and mapping is addressed in this paper, through the design, analysis, and experimental validation of a globally asymptotically stable (GAS) filter. A nonlinear sensor-based system is designed and its dynamics augmented so that the proposed formulation can be considered as linear time-varying for the purpose of observability analysis. This allows the establishment of observability results related to the original nonlinear system that naturally lead to the design of a Kalman filter with GAS error dynamics. The performance of the proposed algorithm is assessed resorting to a set of realistic simulations and to the results obtained from experimental tests.

关键词： design analysis simultaneous localization and mapping Kalman filters asymptotic Observability realistic simulation dynamics Sensor systems gas filters

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Optical position stabilization of an UAV for autonomous landing 7

Optical position stabilization of an UAV for autonomous land...

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7th German Conference on robotics, ROBOTIK 2012

作者： Ax, Markus Thamke, Stefan Kuhnert, Lars Schlemper, Jens Kuhnert, Klaus-Dieter University of Siegen Fak. IV - Electrical Engineering and Computer Science Institute for Real-Time Learning Systems Germany

Vertical Take-Off and Landing (VTOL) capable Mini Unmanned Aerial Vehicles (MUAV) are an economic alternative to real helicopters if local aerial pictures or other aerial measurements are needed. With electronic stabilization, GPS based position-hold and autonomous way-point functions these systems are easy to operate. While autonomous take off and flying are done routinely, this is not true for autonomous landing. GPS based position stabilization, in conjunction with the normally used cheap and small IMUs, is not accurate enough to avoid dangerous moves in the very last moment of the landing operation. While sufficient for an emergency landing this is not suitable as routine operation. In this paper a solution is presented which uses optical flow techniques for position stabilization in the moment just before the touch down to avoid the inaccuracies from the GPS at this critical moment. © 7th German Conference on robotics, ROBOTIK 2012

关键词： Stabilization

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