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A Switched Based Control Strategy for Target Tracking of Autonomous Robotic Vehicles using Range-only Measurements

IFAC Proceedings Volumes 2011年第1期44卷 12819-12824页

作者： Omid Namaki-Shoushtari A. Pedro Aguiar Ali Khaki Sedigh Faculty of Electrical and Computer Engineering K.N. Toosi University of Technology Tehran Iran Institute for Systems and Robotics (ISR) Instituto Superior Técnico (IST) Lisbon Portugal

Abstract In this paper we address the pursuing or target tracking problem where an autonomous robotic vehicle is required to move towards a maneuvering target using range-only measurements. A new switched based control strategy is proposed to solve the pursuing problem that can be described as comprising a continuous cycle of two distinct phases: i) the determination of the bearing, and ii) following the direction computed in the previous step while the range is decreasing. We provide conditions under which the switched closed-loop system achieves convergence of the relative distance error to a small neighborhood around zero. Simulation results are presented and discussed.

关键词： Target tracking Range-only measurements Switching control Autonomous robotic vehicles

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Evaluation of Boosting-SVM and SRM-SVM cascade classifiers in laser and vision-based pedestrian detection

Evaluation of Boosting-SVM and SRM-SVM cascade classifiers i...

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International Conference on Intelligent Transportation

作者： Oswaldo Ludwig Cristiano Premebida Urbano Nunes Rui Araújo Department of Electrical and Computer Engineering Institute of Systems and Robotics University of Coimbra Portugal

Pedestrian detection systems constitute an important field of research and development in computer vision, specially when applied in protection/safety systems in urban scenarios due to their direct impact in the society, specifically in terms of traffic casualties. In order to face such challenge, this work exploits some developments on statistical machine learning theory, in particular structural risk minimization (SRM) in a cascade ensemble. Namely, the ensemble applies the principle of SRM on a set of linear support vector machines (SVM). The linear SVM complexity, in the Vapnik sense, is controlled by choosing the dimension of the feature space in each cascade stage. To support experimental analysis, a multi-sensor dataset constituted by data from a LIDAR, a monocular camera, an IMU, encoder and a DGPS is introduced in this paper. The dataset, named Laser and Image Pedestrian Detection (LIPD) dataset, was collected in an urban environment, at day light conditions, using an electrical vehicle driven at low speed. Labeled pedestrians and non-pedestrians samples are also available for benchmarking purpose. The cascade of SVMs, trained with image-based features (HOG and COV descriptors), is used to detect pedestrian evidences on regions of interest (ROI) generated by a LIDAR-based processing system. Finally, the paper presents experimental results comparing the performance of a Boosting-SVM cascade and the proposed SRM-SVM cascade classifiers, in terms of detection errors.

关键词： Training Support vector machines Feature extraction Robot sensing systems Laser radar Detectors Complexity theory

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A systems design approach to manage mechatronics R&D

A systems design approach to manage mechatronics R&D

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2011 IEEE 5th International Conference on Cybernetics and Intelligent systems, CIS 2011

作者： Pang, Chee Khiang Ng, Tsan Sheng Lewis, Frank L. Lee, Tong Heng Department of Electrical and Computer Engineering National University of Singapore Singapore Singapore Department of Industrial and Systems Engineering National University of Singapore Singapore Singapore Automation and Robotics Research Institute University of Texas at Arlington Fort Worth TX 76118 United States

ISBN: (纸本)9781612841984

We propose a systems design procedure to integrate mechanical design, structural prototyping, and servo evaluation through careful comprehension of the servo-mechanical-prototype production cycle commonly employed in mechatronic industries. Our approach focuses on the Modal Parametric Identification (MPI) of key feedback parameters for fast exchange of design specifications and information to enable efficient conduct of product design evaluations and support schedule compression of the R&D project life cycle. Using the commercial Hard Disk Drive (HDD) as a case example, we demonstrate how our approach allows inter-disciplinary specifications to be communicated amongst engineers from different backgrounds to speed up the R&D process for the next generation of intelligent manufacturing. This provides the project management team with powerful decision-making tools for project strategy formulation, and improvements in project outcome are potentially massive because of the low costs of change. © 2011 IEEE.

关键词： Human resource management

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Algorithms for management of a multi-platooning system of IVC-enabled autonomous vehicles, with high traffic capacity

Algorithms for management of a multi-platooning system of IV...

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International Conference on Intelligent Transportation

作者： Pedro Fernandes Urbano Nunes Institute of Systems and Robotics Department of Electrical and Computer Engineering University of Coimbra Coimbra Portugal

Intra-platoon positioning management strategies to deal with safe and efficient advanced traffic management system operation are proposed in this paper. New algorithms to ensure high traffic capacity are proposed, and Matlab/Simulink-based simulation results are reported. Recently, we proposed new algorithms to mitigate communication delays using anticipatory information, both from the platoon's leader and the followers, with significant impact on the improvement of platoon string stability [5]. In this paper, we argue that maintaining a constant spacing between platoons' leaders has a positive impact on the traffic capacity of the whole system. As such, when the leader and eventually other vehicles immediately behind it leave the platoon, the new leader must accelerate to reach the position of the previous leader, to ensure inter-leader constant spacing and, consequently, enough spacing to be eventually occupied by new followers. We developed a novel architecture where each vehicle consists of two distinct modules: a leader and a follower. Based on Matlab/Simulink-based simulation, the new algorithms are assessed, and simulation results presented. The obtained simulation results confirm that the proposed algorithms adapt the acceleration pattern, ensuring similar timings for all possible cases of the previous position of new leaders in the platoon, when performing their repositioning maneuvers.

关键词： Vehicles Lead Mobile robots Asynchronous transfer mode Delay Acceleration Roads

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Optimal Control on Lie Groups: Implementation Details of the Projection Operator Approach

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IFAC Proceedings Volumes 2011年第1期44卷 14567-14572页

作者： Alessandro Saccon John Hauser A. Pedro Aguiar Institute for Systems and Robotics Instituto Superior Técnico Lisboa Portugal Department of Electrical Computer and Energy Engineering University of Colorado Boulder

Abstract This paper discusses key implementation details required for computing the solution of a continuous-time optimal control problem on a Lie group using the projection operator approach. In particular, we provide the explicit formulas to compute the time-varying linear quadratic problem which defines the search direction step of the algorithm. We also show that the projection operator approach on Lie groups generates a sequence of adjoint state trajectories that converges, as a local minimum is approached, to the adjoint state trajectory of the first order necessary conditions of the Pontryagin's Maximum Principle, placing it between direct and indirect optimization methods. As illustrative example, an optimization problem on SO(3) is introduced and numerical results of the projection operator approach are presented, highlighting second order converge rate of the method.

关键词： Optimal control Lie groups direct method rotation matrix

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Proposal of a new real-time cooperative challenge in mobile robotics

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IFAC Proceedings Volumes 2011年第1期44卷 9836-9841页

作者： P. Costa A. Moreira J. Gonçalves J. Lima Faculty of Engineering of University of Porto Department of Electrical Engineering and Computers Porto Portugal Polytechnic Institute of Bragança Department of Electrical Engineering Bragança Portugal Robotics and Intelligent Systems Research Group INESC Porto Portugal

Abstract In this paper it is presented a new robot competition that is going to be included in Robotica 2011, the main robotics Portuguese Competition. The robot competition takes place in an emulated factory plant, where Automatic Guided Vehicles (AGVs) must cooperate to perform tasks. To accomplish their goals the AGVs must deal with localization, navigation, scheduling and cooperation problems, that must be solved autonomously. One option of prototyping the AGVs is the use of the Lego Mindstorms NXT technology. The presented example can play an important role in education due to the inherent multi-disciplinary concepts that are involved, motivating students to technological areas. It also plays an important role in research and development, because it is expected that the outcomes that will emerge here, will later be transfered to other application areas, such as service robots and manufacturing.

关键词： robotics Education Manufacturing

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A Frenkel-Poole model of dielectric charging in CMOS MEMS

A Frenkel-Poole model of dielectric charging in CMOS MEMS

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International Solid-State Sensors, Actuators and Microsystems Conference

作者： Dorsey, K.L. Fedder, G.K. Department of Electrical and Computer Engineering Carnegie Mellon University Pittsburgh PA United States Robotics Institute Carnegie Mellon University Pittsburgh PA United States Institute for Complex and Engineered Systems Carnegie Mellon University Pittsburgh PA United States

ISBN: (纸本)9781457701573

Electrostatic actuation is commonly used for MEMS devices such as resonators, sensors, and RF switches, but parasitic charge in the dielectric layers of the devices may cause performance issues (e.g., drift, pull-in) or decreased device lifetime. We present a precise predictive model of dielectric charging in a CMOS MEMS resonator using Frenkel-Poole conduction. The model is able to predict frequency drift within 5% of measured drift data. Use of these predictive models will lead to electrostatically actuated MEMS devices with increased stability. © 2011 IEEE.

关键词： Electrostatic actuators

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Collaborative sequential-based detection in wireless sensor networks

Collaborative sequential-based detection in wireless sensor ...

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Asilomar Conference on Signals, systems & Computers

作者： Sabina Zejnilović Joao Pedro Gomes Bruno Sinopoli Department of Electrical and Computer Engineering Carnegie Mellon University Pittsburgh PA USA Institute for Systems and Robotics-Instituto Superior Técnico (ISR/IST) Technical University of Lisbon Lisboa Portugal

Due to limited power resources, energy efficiency is an important aspect of detection in wireless sensor networks. We propose a collaborative detection scheme, based on sequential hypothesis testing, where a randomly chosen node may initiate a collaboration, collecting observations from neighboring nodes to test the hypotheses. Our simulation results show that for large networks and high SNR, the proposed scheme leads to lower communication cost and similar performance when compared to a standard detection setup, where all the observations are collected in a fusion node. We also examine how the energy efficiency of this scheme evolves as a function of the network structure.

关键词： Collaboration Wireless sensor networks Signal to noise ratio Testing Network topology Monitoring Wireless communication

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Large deviations analysis of consensus+innovations detection in random networks

Large deviations analysis of consensus+innovations detection...

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Annual Allerton Conference on Communication, Control, and Computing

作者： Dragana Bajović Dušan Jakovetić José M. F. Moura João Xavier Bruno Sinopoli Department of Electrical and Computer Engineering Carnegie Mellon University Pittsburgh PA USA Institute for Systems and Robotics (ISR) Instituto Superior Técnico (IST) Technical University of Lisbon Lisboa Portugal

We study the large deviations performance of consensus+innovations distributed detection over random networks, where each sensor, at each time k, weight averages its decision variable with its neighbors decision variables (consensus), and accounts for its new observation (innovation). Sensor observations are independent identically distributed (i.i.d.) both in time and space, but have generic (non Gaussian) distributions. The underlying network is random, described by a sequence of i.i.d. stochastic, symmetric weight matrices W(k); we measure the corresponding speed of consensus by |log r|, where r is the second largest eigenvalue of the second moment of W(k). We show that distributed detection exhibits a phase transition behavior with respect to |log r|: when |log r| is above a threshold, distributed detection is equivalent to the optimal centralized detector, i.e., has the error exponent equal to the Chernoff information. We explicitly quantify the optimality threshold for |log r| as a function of the log-moment generating function Λ 0 (·) of a sensor's log- likelihood ratio. When below the threshold, we analytically find the achievable error exponent as a function of r and Λ 0 (·). Finally, we illustrate by an example the dependence of the optimality threshold on the type of the sensor observations distribution.

关键词： Detectors Technological innovation Robot sensing systems Educational institutions Vectors USA Councils Symmetric matrices

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Ensuring ad hoc connectivity in distributed search with Robotic Darwinian Particle Swarms

Ensuring ad hoc connectivity in distributed search with Robo...

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IEEE International Workshop on Safety, Security, and Rescue robotics (SSRR)

作者： Micael S. Couceiro Rui P. Rocha Nuno M. F. Ferreira Institute of Systems and Robotics University of Coimbra Coimbra Portugal RoboCorp Electrical Engineering Department Engineering Institute of Coimbra Coimbra Portugal

This paper presents an enforcing multi-hop network connectivity algorithm experimentally validated using a modified version of the Darwinian Particle Swarm Optimization (DPSO), denoted as RDPSO (Robotic DPSO) on groups of simulated robots performing a distributed exploration task. This work aims to overcome limitations of multi-robot systems (MRS) in difficult scenarios (e.g., search and rescue) concerning the need and the ability to actively maintain an available inter-robot communication channel, through the development of effective multi-robot cooperation without relying on a preexisting communication network. Although there is no linear relationship between the number of robots (i.e., nodes) and the maximum communication range, experimental results show that the decreased performance by the developed algorithm under communication constraints can be overcome by slightly increasing the number of robots as the maximum communication range is decreased.

关键词： Mobile ad hoc networks Robot sensing systems Spirals Spread spectrum communication Vectors

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