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IEEE International Conference on robotics and Automation (ICRA)

作者： Shaojie Shen Nathan Michael Vijay Kumar Department of Electronic and Computer Engineering Hong Kong University of Science and Technology Hong Kong China Robotics Institute Carnegie Mellon University Pittsburgh PA USA GRASP Laboratory University of Pennsylvania Philadelphia PA USA

There have been increasing interests in the robotics community in building smaller and more agile autonomous micro aerial vehicles (MAVs). In particular, the monocular visual-inertial system (VINS) that consists of only a camera and an inertial measurement unit (IMU) forms a great minimum sensor suite due to its superior size, weight, and power (SWaP) characteristics. In this paper, we present a tightly-coupled nonlinear optimization-based monocular VINS estimator for autonomous rotorcraft MAVs. Our estimator allows the MAV to execute trajectories at 2 m/s with roll and pitch angles up to 30 degrees. We present extensive statistical analysis to verify the performance of our approach in different environments with varying flight speeds.

关键词： Cameras Optimization Robot sensing systems Vehicles Quaternions Measurement uncertainty Mathematical model

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Non-parametric consistency test for multiple-sensing-modality data fusion

Non-parametric consistency test for multiple-sensing-modalit...

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International Conference on Information Fusion

作者： Marcos P. Gerardo-Castro Thierry Peynot Fabio Ramos Robert Fitch Australian Centre for Field Robotics (ACFR) University of Sydney NSW Australia School of Electrical Engineering and Computer Science Queensland University of Technology Brisbane QLD Australia School of Information Technologies University of Sydney NSW Australia

Fusing data from multiple sensing modalities, e.g. laser and radar, is a promising approach to achieve resilient perception in challenging environmental conditions. However, this may lead to catastrophic fusion in the presence of inconsistent data, i.e. when the sensors do not detect the same target due to distinct attenuation properties. It is often difficult to discriminate consistent from inconsistent data across sensing modalities using local spatial information alone. In this paper we present a novel consistency test based on the log marginal likelihood of a Gaussian process model that evaluates data from range sensors in a relative manner. A new data point is deemed to be consistent if the model statistically improves as a result of its fusion. This approach avoids the need for absolute spatial distance threshold parameters as required by previous work. We report results from object reconstruction with both synthetic and experimental data that demonstrate an improvement in reconstruction quality, particularly in cases where data points are inconsistent yet spatially proximal.

关键词： Robot sensing systems Data models Three-dimensional displays Silicon Radar Data integration

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Weight update sequence in MLP networks

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Lecture Notes in computer science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) 2014年 8669卷 266-274页

作者： Kordos, Miroslaw Rusiecki, Andrzej Kamiński, Tomasz Greń, Krzysztof University of Bielsko-Biala Department of Mathematics and Computer Science Bielsko-Biala Willowa 2 Poland Wroclaw University of Technology Institute of Computer Engineering Control and Robotics Wroclaw Wybrzeże Wyspiańskiego 27 Poland

ISBN: (纸本)9783319108391

The advantages of Variable Step Search algorithm - a simple local search-based method of MLP training is that it does not require differentiable error functions, has better convergence properties than backpropagation and lower memory requirements and computational cost than global optimization and second order methods. However, in some applications, the issue of training time reduction becomes very important. In this paper we evaluate several approaches to achieve this reduction. © Springer International Publishing Switzerland 2014.

关键词： Global optimization

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Multi-robot long-term persistent coverage with fuel constrained robots

Multi-robot long-term persistent coverage with fuel constrai...

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IEEE International Conference on robotics and Automation (ICRA)

作者： Derek Mitchell Micah Corah Nilanjan Chakraborty Katia Sycara Nathan Michael Robotics Institute Carnegie Mellon University Pittsburgh PA USA Department of Computer Science Rensselaer Polytechnical Institute Troy NY USA Department of Mechanical Engineering Stony Brook University Stony Brook NY USA

ISBN: (纸本)9781479969241

In this paper, we present an algorithm to solve the Multi-Robot Persistent Coverage Problem (MRPCP). Here, we seek to compute a schedule that will allow a fleet of agents to visit all targets of a given set while maximizing the frequency of visitation and maintaining a sufficient fuel capacity by refueling at depots. We also present a heuristic method to allow us to compute bounded suboptimal results in real time. The results produced by our algorithm will allow a team of robots to efficiently cover a given set of targets or tasks persistently over long periods of time, even when the cost to transition between tasks is dynamic.

关键词： Robots Fuels Vehicles Heuristic algorithms Routing Upper bound Vehicle dynamics

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Interactive perception of articulated objects 12

Interactive perception of articulated objects

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12th International Symposium on Experimental robotics, ISER 2010

作者： Katz, Dov Orthey, Andreas Brock, Oliver Robotics and Biology Laboratory School of Electrical Engineering and Computer Science Technische Universität Berlin Germany

ISBN: (纸本)9783642285714

We present a skill for the perception of three-dimensional kinematic structures of rigid articulated bodies with revolute and prismatic joints. The ability to acquire such models autonomously is required for general manipulation in unstructured environments. Experiments on a mobile manipulation platform with real-world objects under varying lighting conditions demonstrate the robustness of the proposed method. This robustness is achieved by integrating perception and manipulation capabilities: the manipulator interacts with the environment to move an unknown object, thereby creating a perceptual signal that reveals the kinematic properties of the object. For good performance, the perceptual skill requires the presence of trackable visual features in the scene. © Springer-Verlag Berlin Heidelberg 2014.

关键词： Kinematics

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Hierarchical Classification of Large-Scale Patient Records for Automatic Treatment Stratification

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IEEE Journal of Biomedical and Health Informatics 2015年第4期19卷 1234-1245页

作者： Mei, Kuizhi Peng, Jinye Gao, Ling Zheng, Naiquan Nigel Fan, Jianping Institute of Artificial Intelligence and Robotics Xi'An Jiaotong University Xi'an710049 China School of Information Science and Technology Northwest University Xi'an710069 China Center of Biomedical Engineering University of North Carolina at Charlotte NC28223 United States Department of Computer Science University of North Carolina at Charlotte NC28223 United States

In this paper, a hierarchical learning algorithm is developed for classifying large-scale patient records, e.g., categorizing large-scale patient records into large numbers of known patient categories (i.e., thousands of known patient categories) for automatic treatment stratification. Our hierarchical learning algorithm can leverage tree structure to train more discriminative max-margin classifiers for high-level nodes and control interlevel error propagation effectively. By ruling out unlikely groups of patient categories (i.e., irrelevant high-level nodes) at an early stage, our hierarchical approach can achieve log-linear computational complexity, which is very attractive for big data applications. Our experiments on one specific medical domain have demonstrated that our hierarchical approach can achieve very competitive results on both classification accuracy and computational efficiency as compared with other state-of-the-art techniques. © 2015 IEEE.

关键词： Learning algorithms

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Learning multiple collaborative tasks with a mixture of Interaction Primitives

Learning multiple collaborative tasks with a mixture of Inte...

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IEEE International Conference on robotics and Automation (ICRA)

作者： Marco Ewerton Gerhard Neumann Rudolf Lioutikov Heni Ben Amor Jan Peters Guilherme Maeda Department of Computer Science Technische Universität Darmstadt Darmstadt Germany Institute of Robotics and Intelligent Machines Georgia Institute of Technology Atlanta GA USA 3Max Planck Institute for Intelligent Systems Tuebingen Germany

Robots that interact with humans must learn to not only adapt to different human partners but also to new interactions. Such a form of learning can be achieved by demonstrations and imitation. A recently introduced method to learn interactions from demonstrations is the framework of Interaction Primitives. While this framework is limited to represent and generalize a single interaction pattern, in practice, interactions between a human and a robot can consist of many different patterns. To overcome this limitation this paper proposes a Mixture of Interaction Primitives to learn multiple interaction patterns from unlabeled demonstrations. Specifically the proposed method uses Gaussian Mixture Models of Interaction Primitives to model nonlinear correlations between the movements of the different agents. We validate our algorithm with two experiments involving interactive tasks between a human and a lightweight robotic arm. In the first, we compare our proposed method with conventional Interaction Primitives in a toy problem scenario where the robot and the human are not linearly correlated. In the second, we present a proof-of-concept experiment where the robot assists a human in assembling a box.

关键词： Trajectory Robot kinematics Handover Hidden Markov models Fasteners

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A method for fast 3D imaging of contrast enhanced vessels or catheters using magnetic resonance projections

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Physica Medica 2016年 32卷 248-248页

作者： M. Unan I. Seimenis A.G. Webb N.V. Tsekos Medical Robotics Laboratory Dept of Computer Science University of Houston Houston TX USA Democritus University of Thrace Medical School Medical Physics Laboratory Alexandroupolis Greece C.J. Gorter Center for High Field MRI Leiden University Medical Center Leiden Netherlands

Introduction With a plethora of soft-tissue contrast mechanisms, lack of ionizing radiation and on-the-fly computer controller adjustment of imaging parameters, MRI has emerged as an alternative modality for guiding interventions. However, due to its inherent low signal sensitivity, conventional MRI cannot achieve the high speeds of X-ray fluoroscopy . Purpose To address this, we describe a novel approach for 3D MRI of tubular structures such as blood vessels or catheters, based on the collection of thick slab spatially matched projections. Materials and methods The implemented method includes the following: three elements. (1) Collection of three orthogonal projections of the same volume that contains the structure with a GRE (TR/TE = 26.07/3.71 ms, angle = 75°, matrix = 256 × 256, FOV = 200 × 200 mm 2 , slice = 200 mm). (2) Segmentation of the 2D structures on the three projections. (3) Reconstruction of the 3D structure by back projection. The method was tested on phantoms with vessel-mimicking structures made of tubing filled with 2% Gd-agent in a fatty matrix. The ground truth was an MRA (128 slices, TR/TE = 3.8/1.52 ms, angle = 40°, matrix = 384 × 264, FOV = 191 × 131 mm 2 , slice = 1.3 mm). Results The 3D centerline of the rendered structures was extracted and then found to be virtually the same (±pixel) to this extracted from a multislice MRA of the same structure. Conclusion The method can accurately image 3D tubular object in 20 s as compared to 186 s with the used MRA. Disclosure None of the authors has anything to declare.

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Confidence Preserving Machine for Facial Action Unit Detection

Confidence Preserving Machine for Facial Action Unit Detecti...

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International Conference on computer Vision (ICCV)

作者： Jiabei Zeng Wen-Sheng Chu Fernando De la Torre Jeffrey F. Cohn Zhang Xiong School of Computer Science and Engineering Beihang University Beijing China Robotics Institute Carnegie Mellon University Pittsburgh PA USA Carnegie Mellon University Pittsburgh PA US Department of Psychology University of Pittsburgh Pittsburgh PA USA

ISBN: (纸本)9781467383929

Varied sources of error contribute to the challenge of facial action unit detection. Previous approaches address specific and known sources. However, many sources are unknown. To address the ubiquity of error, we propose a Confident Preserving Machine (CPM) that follows an easy-to-hard classification strategy. During training, CPM learns two confident classifiers. A confident positive classifier separates easily identified positive samples from all else, a confident negative classifier does same for negative samples. During testing, CPM then learns a person-specific classifier using "virtual labels" provided by confident classifiers. This step is achieved using a quasi-semi-supervised (QSS) approach. Hard samples are typically close to the decision boundary, and the QSS approach disambiguates them using spatio-temporal constraints. To evaluate CPM, we compared it with a baseline single-margin classifier and state-of-the-art semi-supervised learning, transfer learning, and boosting methods in three datasets of spontaneous facial behavior. With few exceptions, CPM outperformed baseline and state-of-the art methods.

关键词： Training Gold Support vector machines Magnetic heads Manifolds Testing Boosting

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A combined geometrical and topological simplification hierarchy for terrain analysis 14

A combined geometrical and topological simplification hierar...

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22nd ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems, ACM SIGSPATIAL GIS 2014

作者： Iuricich, Federico De Floriani, Leila Department of Computer Science and UMIACS University of Maryland College ParkMD United States Dept. of Computer Science Bioengineering Robotics and Systems Engineering University of Genova Italy

ISBN: (纸本)9781450331319

We consider the problem of modeling a terrain from both a geo-metric and a morphological point of view for efficient and effective terrain analysis on large data sets. We devise and implement a sim-plification hierarchy for a triangulated terrain, where the terrain is represented as a triangle mesh and its morphology is described by a discrete Morse gradient field defined on the basis on the eleva-tion values given at the vertices of the mesh. The discrete Morse gradient is attached to the triangles, edges and vertices of the mesh. We define a new edge-contraction operator for the edges of the tri-angle mesh, which does not change the behavior of the gradient flow and does not create new critical points, and we apply it to the original full-resolution mesh in combination with a topological sim-plification operator which eliminates critical simplices in pair. We build the simplification hierarchy based on suitably combining such operators and we evaluate it experimentally. © Copyright 2014 ACM.

关键词： Topology

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