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Flexible triangular formation keeping of marine robotic vehicles using range measurements 1

IFAC Proceedings Volumes 2014年第3期47卷 5145-5150页

作者： Francisco Rego Jorge M. Soares António Pascoal A. Pedro Aguiar Colin Jones Laboratory of Robotics and Systems in Engineering and Science Instituto Superior Técnico University of Lisbon Lisbon Portugal Department of Electrical and Computer Engineering Faculty of Engineering University of Porto Porto Portugal Institute of Mechanical Engineering School of Engineering École Polytechnique Fédérale de Lausanne Lausanne Switzerland Distributed Intelligent Systems and Algorithms Laboratory School of Architecture Civil and Environmental Engineering École Polytechnique Fédérale de Lausanne Lausanne Switzerland National Institute of Oceanography Dona Paula Goa India

This paper addresses the problem of keeping an autonomous marine vehicle in a moving triangular formation by regulating its position with respect to two leader vehicles. The follower vehicle has no prior knowledge of the path described by the leaders but has access to their heading angle and is able to measure inter-vehicle ranges. It is assumed that the distance between the leaders is constant and known. A control strategy is adopted that generates speed and heading commands so as to drive suitably defined along track and cross track errors to zero. The commands are used as input to local inner loops for yaw and speed control. The paper describes the algorithms derived for range-based control and assesses their performance in simulations using realistic models of the vehicles involved. Tests with three autonomous marine vehicles equipped with acoustic modems and ranging devices allow for the evaluation of the performance of the algorithms in a real-world situation.

关键词： Autonomous Vehicles Marine systems Control Laws Formation Control Station Keeping Triangular Formations

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Time dilation visualization in relativity 90

Time dilation visualization in relativity

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Proceedings of the 1990 ACM/IEEE conference on Supercomputing

作者： Ping-Kang Hsiung Robert H. Thibadeau Christopher B. Cox Robert H. P. Dunn Department of Electrical and Computer Engineering Carnegie Mellon University Pittsburgh Pennsylvania Imaging Systems Laboratory The Robotics Institute Carnegie Mellon University Pittsburgh Pennsylvania Department of Physics Carnegie Mellon University Pittsburgh Pennsylvania Department of Art Carnegie Mellon University Pittsburgh Pennsylvania

ISBN: (纸本)9780897914123

This work extends our previous effort in visualizing the spatial aspect of relativistic effects, and treats the phenomenon of time dilation; an inherent temporal effect of special ***, we demonstrate through still-frame images and live animations that in observing the viewing independent time dilation, the finite light transit time involved in performing the observation makes the observed time dilation also depend on the viewing *** we introduce the physics of special relativity into ray-tracing and make time to pass as a ray travels through space, we are able to link the spatial and temporal dimensions in a fundamental and consistent way in our simulations, and generate images that reveal the spatial and temporal properties of the 4D geometry of *** exploration highlights the interplay of the imaging process and the imaged physical events in producing the final images. It reveals a richly detailed physical reality which the mathematical language of thought experiment in relatively does not directly provide.

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Global Trajectory Tracking for a Class of Underactuated Vehicles

Global Trajectory Tracking for a Class of Underactuated Vehi...

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American Control Conference

作者： Pedro Casau Ricardo G. Sanfelice Rita Cunha David Cabecinhas Carlos Silvestre Department of Electrical Engineering and Computer Science and Institute for Robotics and Systems in Engineering and Science (LARSyS) Instituto Superior Técnico Universidade Técnica de Lisboa 1049-001 Lisboa Portugal Department of Aerospace and Mechanical Engineering University of Arizona 1130 N. Mountain Ave AZ 85721

ISBN: (纸本)9781479901777

In this paper, we address the problem of trajectory tracking for a class of underactuated vehicles with full torque actuation and only one dimensional force actuation (thrust). For this class of vehicles, the desired thrust is defined by a saturated control law that achieves global asymptotic stabilization of the position tracking error. The proposed control law also assures that the third component of the angular velocity is regulated to zero. To accomplish this task we propose a hybrid controller that is designed using backstepping techniques and recent developments on synergistic Lyapunov functions. Simulations validating the results are also provided.

关键词： position tracking error angular velocity is regulated to zero results are also provided trajectory tracking Location tracking vehicle peak torque Classes control law ANGULAR VELOCITY Activation thrust saturating control

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Metal-filled carbon nanotubes for nanofluidic systems: Modes of melting and evaporation

Metal-filled carbon nanotubes for nanofluidic systems: Modes...

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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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A New Graph Model with Random Edge Values: Connectivity and Diameter

A New Graph Model with Random Edge Values: Connectivity and ...

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Annual Allerton Conference on Communication, Control, and Computing

作者： Richard J. La Maya Kabkab the Department of Electrical & Computer Engineering (ECE) and the Institute for Systems Research (ISR) University of MarylandCollege Park MD 20742.

ISBN: (纸本)9781479934119

We introduce a new random graph model. In our model, n, n ≥ 2, vertices choose a subset of potential edges by considering the (estimated) benefits or utilities of the edges. More precisely, each vertex selects k, k ≥ 1, incident edges it wishes to set up, and an edge between two vertices is present in the graph if and only if both of the end vertices choose the edge. First, we examine the scaling law of the smallest k needed for graph connectivity with increasing n and prove that it is θ(log(n)). Second, we study the diameter of the random graph and demonstrate that, under certain conditions on k, the diameter is close to log(n)/ log(log(n)) with high probability. In addition, as a byproduct of our findings, we show that, for all sufficiently large n, if k > β* log(n), where β*≈ 2.4626, there exists a connected Erd?s-Rényi random graph that is embedded in our random graph with high probability.

关键词： graph edge scaling law

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Passive Quadrupedal Gait Synchronization for Extra Robotic Legs Using a Dynamically Coupled Double Rimless Wheel Model

arXiv

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arXiv 2020年

作者： Gonzalez, Daniel J. Harry Asada, H. Robotics Research Center Department of Electrical Engineering and Computer Science United States Military Academy West PointNY10996 United States d’Arbeloff Laboratory for Information Systems and Technology Department of Mechanical Engineering Massachusetts Institute of Technology CambridgeMA02139 United States

The Extra Robotic Legs (XRL) system is a robotic augmentation worn by a human operator consisting of two articulated robot legs that walk with the operator and help bear a heavy backpack payload. It is desirable for the Human-XRL quadruped system to walk with the rear legs lead the front by 25% of the gait period, minimizing the energy lost from foot impacts while maximizing balance stability. Unlike quadrupedal robots, the XRL cannot command the human’s limbs to coordinate quadrupedal locomotion. Using a pair of Rimless Wheel models, it is shown that the systems coupled with a spring and damper converge to the desired 25% phase difference. A Poincaré return map was generated using numerical simulation to examine the convergence properties to different coupler design parameters, and initial conditions. The Dynamically Coupled Double Rimless Wheel system was physically realized with a spring and dashpot chosen from the theoretical results, and initial experiments indicate that the desired synchronization properties may be achieved within several steps using this set of passive components alone. Copyright © 2020, The Authors. All rights reserved.

关键词： Exoskeleton (robotics)

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End-to-end Semantic Segmentation Network for Low-Light Scenes

End-to-end Semantic Segmentation Network for Low-Light Scene...

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IEEE International Conference on robotics and Automation (ICRA)

作者： Hongmin Mu Gang Zhang MengChu Zhou Zhengcai Cao College of Information Science and Technology Beijing University of Chemical Technology Beijing China Department of Macao Institute of Systems Engineering Macau University of Science and Technology Macao China Helen and John C. Hartmann Department of Electrical and Computer Engineering New Jersey Institute of Technology Newark NJ USA State Key Laboratory of Robotics and Systems Harbin Institute of Technology Harbin China

ISBN: (数字)9798350384574

ISBN: (纸本)9798350384581

In the fields of robotic perception and computer vision, achieving accurate semantic segmentation of low-light or nighttime scenes is challenging. This is primarily due to the limited visibility of objects and the reduced texture and color contrasts among them. To address the issue of limited visibility, we propose a hierarchical gated convolution unit, which simultaneously expands the receptive field and restores edge texture. To address the issue of reduced texture among objects, we propose a dual closed-loop bipartite matching algorithm to establish a total loss function consisting of the unsupervised illumination enhancement loss and supervised intersection-over-union loss, thus enabling the joint minimization of both losses via the Hungarian algorithm. We thus achieve end-to-end training for a semantic segmentation network especially suitable for handling low-light scenes. Experimental results demonstrate that the proposed network surpasses existing methods on the Cityscapes dataset and notably outperforms state-of-the-art methods on both Dark Zurich and Nighttime Driving datasets.

关键词： Training computer vision Accuracy Convolution Semantic segmentation Lighting Logic gates

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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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Design of H_(infinity) Command and Control Loops for Unmanned Aerial Vehicles using Static Output-Feedback

Design of H_(infinity) Command and Control Loops for Unmanne...

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Proceedings of the 46th IEEE Conference on Decision and Control, Pages 1-459

作者： J. Gadewadikar F. Lewis K. Subbarao Ben M. Chen Systems Research Institute Department of Advanced Technologies Alcorn State University USA Automation and Robotics Research Institute University of Texas Arlington Fort worth TX USA Mechanical and Aerospace Department University of Texas Arlington TX USA Department of Electrical & Computer Engineering National University of Singapore Singapore

The aim of this paper is to design a helicopter position control system with guaranteed performance that allows tracking control of Unmanned Aerial Vehicle positions -^sX, Y, Z, and yaw while preserving a structure that is generally accepted in the helicopter control community. The paper presents an approach for designing compensators for shaping the closed-loop inertial positions and yaw step response using H_(infinity) output-feedback design techniques. Simplified conditions are used which only require the solution of two coupled matrix design equations. H_(infinity) framework is utilized to pose the problem of stabilization as an outer position command loop and an inner control loop. Inner loop controls attitude rates along with roll and pitch and provides robustness and structure. This paper thereby presents a design for hover and station-keeping control of UAV helicopters. It is shown that the rotorcraft model can be first loop shaped to achieve desired characteristics about the hover operating condition. A numerically efficient solution algorithm to solve the H_(infinity) coupled design equations for both inner and outer loops is used. A major contribution is that an initial stabilizing gain is not needed. The efficacy of the control law and the disturbance accommodation properties are shown on a rotorcraft design example.

关键词： Helicopters Unmanned aerial vehicles Control systems Attitude control Riccati equations Vehicle dynamics Output feedback Linear matrix inequalities Shape control USA Councils

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Effects of Robotic Expertise and Task Knowledge on Physical Ergonomics and Joint Efficiency in a Human-Robot Collaboration Task

Effects of Robotic Expertise and Task Knowledge on Physical ...

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IEEE-RAS International Conference on Humanoid Robots

作者： Matteo Pantano Arianna Curioni Daniel Regulin Tobias Kamps Dongheui Lee Technology department Siemens Aktiengesellschaft Munich Germany Department of Electrical and Computer Engineering Human-Centered Assistive Robotics Technical University of Munich Munich Germany Autonomous Systems Institut für Computertechnik Technische Uni-versitat Wien Vienna Austria Institute of Robotics and Mechatronics German Aerospace Center Wessling Germany

With the trend of low batch manufacturing, more and more small and medium enterprises are leaning towards adopting collaborative robots to increase productivity and improve operator well-being. However, robots are often programmed by robot experts rather than the operators effectively working with the machine. Therefore, operators may perceive low levels of task autonomy due to the unpredictability of robot motions. Empowering operators to make their own choices regarding robot motions can improve such feelings. However, research in cognitive science shows that allowing operators to decide on robot motions in a collaborative task could be influenced by how people consider their travel path and their partner's action. To better understand these relations, considering preliminary results from a previous study, we designed a user study where we tested operators' decisions in a collaborative task where groups of robot experts and novices were asked to choose their preferred task configuration among four possible options that differed in terms of operators' physical ergonomics and robot travel path. Our results show that robotic experts prioritize joint team work rather than their ergonomics. Contrarily, novices prioritize individual efforts and tend to reduce the robot travel path while keeping their travel path constant, maintaining good physical ergonomics. In conclusion, providing operators with task decision autonomy can be advantageous, but operator background must be considered to ensure optimal physical ergonomics and travel paths.

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