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IEEE/RAS-EMBS International Conference on Biomedical robotics and Biomechatronics (BioRob)

作者： Wesley Roozing Ludo C. Visser Raffaella Carloni Faculty of Electrical Engineering Mathematics and Computer Science University of Twente The Netherlands Department of Advanced Robotics Istituto Italiano di Tecnologia Genova

The Spring-Loaded Inverted Pendulum (SLIP) model has been shown to exhibit many properties of human walking, and therefore has been the starting point for studies on robust, energy-efficient walking for robots. In this paper, the problem of gait variation during walking on the SLIP model is addressed by controlling the leg stiffness and the angle-of-attack in order to switch between gaits and thus regulate walking speeds. We show that it is possible to uniquely describe SLIP limit cycle gaits in fully normalised form. Using that description, we propose both an instantaneous switching method and an interpolation method with an optimisation step to switch between limit cycle SLIP gaits. Using simulations, we show that it is then possible to transition between them, after which the system converges back to zero-input limit cycle walking.

关键词： Legged locomotion Switches Optimized production technology Limit-cycles Hip Trajectory

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BBN viser trecviD 2014 multimedia event detection and multimedia event recounting systems

BBN viser trecviD 2014 multimedia event detection and multim...

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2014 TREC Video Retrieval Evaluation, TRECVID 2014

作者： Luisier, Florian Tickoo, Manasvi Andrews, Walter Ye, Guangnan Liu, Dong Chang, Shih-Fu Salakhutdinov, Ruslan Morariu, Vlad Davis, Larry Gupta, Abhinav Haritaoglu, Ismail Guler, Sadiye Morde, Ashutosh Speech Language and Multimedia Business Unit Raytheon BBN Technologies CambridgeMA United States Department of Electrical Engineering Columbia University New York United States Department of Computer Science University of Toronto Toronto Canada Department of Computer Science University of Maryland United States Robotics Institute Carnegie Mellon University United States Polar Rain Inc Menlo Park United States IntuVision Inc. WoburnMA United States

In this paper, we describe the Raytheon BBN Technologies (BBN) led VISER system for the TRECVID 2014 Multimedia Event Detection (MED) and Recounting (MER) tasks. We present a comprehensive analysis of the different modules: (1) Metadata Generator (MG) - a large suite of audio-visual low-level and sematic features;a set of deep convolutional neural network (DCNN) features trained on the ImageNet dataset;automatic speech recognition (ASR);videotext detection and recognition (OCR). For the low-level features, we used D-SIFT, Opponent SIFT, dense trajectories (HOG+HOF+MBH), MFCC and Fisher Vector (FV) representation. For the semantic concepts, we have trained 1,800 weakly supervised concepts from the Research Set videos and a set of YouTube videos. These concepts include objects, actions, scenes, as well as noun-verb bigrams. We also consider the output layer of the DCNN as a 1,000-dimensional semantic feature. For the speech and videotext content, we leveraged rich confidence-weighted keywords and phrases obtained from the BBN ASR and OCR systems. (2) Event Query Generation (EQG) - linear SVM event models are trained for each feature and combined using probabilistic late fusion framework. Our system involves both SVM-based and query-based detections, to achieve superior performance despite the varying number of positive videos in the different training conditions. We present a thorough study and evaluation of different features used in our system. (3) Event Search (ES) - At search time, simple dot products with the SVM hyperplane are computed for each feature and consequently rescaled into a posterior probability score for each video. (4) Semantic Query Generation (SQG) - we use the Indri Document Retrieval System to search for the closest words/terms to the given event name in a static offline corpus of around 100,000 Wikipedia and Gigapedia documents. After basic text processing, these words (ranked by TF-IDF measure) are then projected into our concept vocabulary us

关键词： Videotex

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Multi-sensor and prediction fusion for contact detection and localization

Multi-sensor and prediction fusion for contact detection and...

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IEEE-RAS International Conference on Humanoid Robots

作者： Javier Felip Antonio Morales Tamim Asfour Department of Computer Science and Engineering Universitat Jaume I Castellon Spain Institute for Anthropomatics and Robotics Karlsruhe Institute of Technology Karlsruhe Germany

Robot perception of physical interaction with the world can be achieved based on different sensory modalities: tactile, force-torque, vision, laser, sonar, proprioception, accelerometers, etc. An important problem and research topic in robotics is the question of how to fuse multiple sensory modalities to provide the robot with advanced perception capabilities. However, in the context of contact localization in grasping and manipulation tasks, the fusion of multiple sensory information has not been addressed so far. We propose a sensory information fusion approach for contact detection and localization. The approach relies on the generation of contact hypotheses and the fusion of these hypotheses to determine the likelihood of a contact at a certain location leading to an improved robustness and precision of contact detection. In addition, the approach allows the integration of multiple sensors, environment, context and predictions. We have implemented the proposed approach on two dual-arm robots and validated it through several experiments.

关键词： Generators Robot sensing systems Geometry Sensor fusion Force

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An efcient GP approach to recognizing cognitive tasks from fNIRS neural signals

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science China(Information sciences) 2013年第10期56卷 277-283页

作者： AN Jinungn LEE JongHyun AHN ChangWook Robotics Research Division Daegu Gyeongbuk Institute of Science & Technology Department of Computer Engineering Sungkyunkwan University

This paper presents a new genetic programming(GP)approach to accurately classifying cognitive tasks from non-stationary and noisy fNIRS neural *** this end,a new GP that efectively handles multiclass problems is *** accordance with multi-tree structure,GP operators are innovated:crossover exchanges every subtree of parents without sufering from any incongruity problem and mutation fne-tunes candidate solutions by a less destructive *** results verifes the efectiveness of the proposed GP classifer over existing references.

关键词： classifcation cognitive task genetic programming fNIRS multi-tree representation

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Vibration control design for a flexible string with input saturation

Vibration control design for a flexible string with input sa...

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World Congress on Intelligent Control and Automation (WCICA)

作者： Wei He Chen Sun Shuzhi Sam Ge Robotics Institute and School of Automation Engineering University of Electronic Science and Technology of China Chengdu China Department of Electrical & Computer Engineering National University of Singapore Singapore Singapore

In this paper, we consider the vibration control problem of a flexible string system in the presence of input saturation. The dynamics of the string system are represented by the coupled partial differential equation (PDE) and ordinary differential equation (ODE). In order to suppress the transverse vibration of the flexible string system, boundary control is proposed by introducing a well-defined integral Lyapunov function. An auxiliary system is introduced to handle the effect of input saturation, and the proof for the existence and the uniqueness of the solution of the closed-loop system is presented. The exponential stability is achieved through rigorous analysis without any simplification of the dynamics. The results are illustrated with numerical simulations for verifying the control performance.

关键词： Vibrations Closed loop systems Boundary conditions Equations Stability analysis Educational institutions

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Semi-supervised Low-rank Representation for Image Representation with Label Constraint

Semi-supervised Low-rank Representation for Image Representa...

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2014年国际计算机科学与软件工程学术会议

作者： Chen-Xue YANG Mao YE Jiao BAO Chao ZHANG School of Computer Science and Engineering Center for RoboticsKey Laboratory for NeuroInformation o Marketing Execution Department ITHuaweiChengduP.R.China

LRR is a popular technique for learning an efficient representation of image information and is reported to have excellent performance in machine learning and computer ***,LRR is an unsupervised method and has poor applicability and performance in real scenarios because of lack of image *** this paper,we propose a novel semi-supervised approach for studying the lowest-rank representation among all the coefficient matrices that represent the images as linear combinations of the basis in the given dictionary,called semi-supervised Low-Rank Representation (semi-LRR),which incorporates the label information as an additional hard ***,we develop an optimization process in which the improvement of the discriminating power of the low rank decomposition is presented explicitly by adding the label information constraint.A semi-LRR graph is constructed to represent data structures for semi-supervised learning and the weights of edges in the graph is provided by seeking a low-rank and sparse *** experimental results show the effectiveness of semi-LRR in comparison to the state-of-the-art approaches.

关键词： Low-rank representation Semi-supervised learning Image representation

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Needle steering in biological tissue using ultrasound-based online curvature estimation

Needle steering in biological tissue using ultrasound-based ...

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IEEE International Conference on robotics and Automation (ICRA)

作者： Pedro Moreira Sachin Patil Ron Alterovitz Sarthak Misra Technical Medicine (Robotics and Mechatronics) University of Twente The Netherlands Department of Electrical Engineering and Computer Sciences University of California at Berkeley USA Department of Computer Science University of North Carolina at Chapel Hill USA

Percutaneous needle insertions are commonly performed for diagnostic and therapeutic purposes. Accurate placement of the needle tip is important to the success of many needle procedures. The current needle steering systems depend on needle-tissue-specific data, such as maximum curvature, that is unavailable prior to an interventional procedure. In this paper, we present a novel three-dimensional adaptive steering method for flexible bevel-tipped needles that is capable of performing accurate tip placement without previous knowledge about needle curvature. The method steers the needle by integrating duty-cycled needle steering, online curvature estimation, ultrasound-based needle tracking, and sampling-based motion planning. The needle curvature estimation is performed online and used to adapt the path and duty cycling. We evaluated the method using experiments in a homogenous gelatin phantom, a two-layer gelatin phantom, and a biological tissue phantom composed of a gelatin layer and in vitro chicken tissue. In all experiments, virtual obstacles and targets move in order to represent the disturbances that might occur due to tissue deformation and physiological processes. The average targeting error using our new adaptive method is 40% lower than using the conventional non-adaptive duty-cycled needle steering method.

关键词： Needles Phantoms Biological tissues Ultrasonic imaging Estimation Target tracking

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Cyclic Scheduling of Multimodal Processes in Crystalline-like Network Structures

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Procedia computer science 2014年 35卷 1567-1576页

作者： Grzegorz Bocewicz Robert Wójcik Zbigniew Banaszak Department of Electronics and Computer Science Koszalin University of Technology Sniadeckich 2 Koszalin Poland Institute of Computer Engineering Control and Robotics Wrocław University of Technology Wroclaw Poland Department of Business Informatics Warsaw University of Technology Narbutta 85 02-524 Warsaw Poland

The paper introduces the concept of a crystalline-like model of a computer communication network (CCN) composed of routers forming a repeating or periodic arrangement. The considered homogenous network assumes the same routers servicing the same number of transmissions form an array. In such a network several isomorphic sub-networks encompassing packet transmission processes serviced by each router, interact each other as to provide a variety of demand-responsive host-server transmission services. In that context, a crystalline-like layout of physically different, however functionally identical, routers provides a homogenous array supporting computer network flows. In turn, packet transmission flows are treated as multimodal processes encompassing arbitrarily given inter-computer communications. Assuming the packets passing their origin-destination routes are synchronized by the same mechanism of packet transmission the problem boils down to a communication processes scheduling. Since concurrent transmission flows are processed along the same presumed routes, hence the schedules sought are cyclic ones. In general case, cycles of multimodal processes depend on CNN's periodicity. That objective to develop conditions allowing one to calculate the cyclic schedule of whole CCN while taking into account only periodicity of its repeating isomorphic structure.

关键词： cyclic scheduling multimodal networks constraint programming structures composition

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Flexible triangular formation keeping of marine robotic vehicles using range measurements 19

Flexible triangular formation keeping of marine robotic vehi...

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19th IFAC World Congress on International Federation of Automatic Control, IFAC 2014

作者： Rego, Francisco Soares, Jorge M. Pascoal, António Aguiar, A. Pedro Jones, Colin 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

ISBN: (纸本)9783902823625

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. © IFAC.

关键词： Vehicle performance

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Optimal Sensor Trajectories for Mobile Underwater Target Positioning with Noisy Range Measurements

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IFAC Proceedings Volumes 2014年第3期47卷 5139-5144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

There is considerable interest in reducing the number of sensors/beacons involved in underwater positioning/navigation systems since this has the potential to drastically reduce the costs and the time spent in deploying, calibrating, and recovering acoustic equipment at sea. Motivated by these considerations, we address the problem of single underwater target positioning based on acoustic range measurements between the target and a moving sensor at the sea surface. In particular, the goal of the present work is to compute optimal geometric trajectories for the surface sensor that will, in a well defined sense, maximize the range-related information available for underwater target positioning and tracking. To this effect, the Fisher Information Matrix and the maximization of its determinant are used to determine the sensor trajectory that yields the most accurate positioning of the target, while the latter describes a preplanned trajectory. It is shown that the optimal trajectory depends on the velocity of the sensor, the velocity and trajectory of the target, the sampling time between measurements, the measurement error model, and the number of measurements used to compute the FIM. Simulation examples illustrate the key results derived.

关键词： Autonomous underwater vehicles Fisher information matrix Cramer-Rao Bound optimization positioning single tracker

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