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International Conference on Computer Vision theory and Applications (VISAPP)

作者： Svenja Kahn Dominik Haumann Volker Willert Fraunhofer IGD Darmstadt Germany TU Darmstadt Control Theory and Robotics Lab Darmstadt Germany

ISBN: (纸本)9781479976867

Real time 3D imaging applications such as on the fly 3D inspection or 3D reconstruction can be created by rigidly coupling a depth camera with an articulated measurement arm or a robot. For such applications, the “hand-eye transformation” between the depth camera and the measurement arm needs to be known. For depth cameras, the hand-eye transformation can either be estimated using 2D images or the 3D measurements captured by the depth camera. This paper investigates the comparison between 2D image based and 3D measurement based hand-eye-calibration. First, two hand-eye calibration approaches are introduced which differ in the way the camera pose is estimated (either with 2D or with 3D data). The main problem in view of the evaluation is, that the ground truth hand-eye transformation is not available and thus a direct evaluation of the accuracy is not possible. Therefore, we introduce quantitative 2D and 3D error measures that allow for an implicit evaluation of the accuracy of the calibration without explicitly knowing the real ground truth transformation. In view of 3D precision, the 3D calibration approach provides more accurate results on average but requires more manual preparation and much more computation time than the 2D approach.

关键词： Three-dimensional displays Cameras Calibration Solid modeling Robot vision systems Coordinate measuring machines

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Making active-probing-based network intrusion detection in Wireless Multihop Networks practical: A Bayesian inference approach to probe selection

Making active-probing-based network intrusion detection in W...

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Conference on Local Computer Networks (LCN)

作者： Rodrigo do Carmo Justus Hoffmann Volker Willert Matthias Hollick Secure Mobile Networking Lab (SEEMOO) TU Darmstadt Darmstadt Germany Control Theory and Robotics Lab TU Darmstadt Darmstadt Germany

Practical intrusion detection in Wireless Multihop Networks (WMNs) is a hard challenge. The distributed nature of the network makes centralized intrusion detection difficult, while resource constraints of the nodes and the characteristics of the wireless medium often render decentralized, node-based approaches impractical. We demonstrate that an active-probing-based network intrusion detection system (AP-NIDS) is practical for WMNs. The key contribution of this paper is to optimize the active probing process: we introduce a general Bayesian model and design a probe selection algorithm that reduces the number of probes while maximizing the insights gathered by the AP-NIDS. We validate our model by means of testbed experimentation. We integrate it to our open source AP-NIDS DogoIDS and run it in an indoor wireless mesh testbed utilizing the IEEE 802.11s protocol. For the example of a selective packet dropping attack, we develop the detection states for our Bayes model, and show its feasibility. We demonstrate that our approach does not need to execute the complete set of probes, yet we obtain good detection rates.

关键词： Probes Intrusion detection Testing Wireless communication Bayes methods Spread spectrum communication Equations

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Dynamics identification of a damped multi elastic link robot arm under gravity

Dynamics identification of a damped multi elastic link robot...

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IEEE International Conference on robotics and Automation (ICRA)

作者： Jörn Malzahn Rene Felix Reinhart Torsten Bertram Institute of Control Theory and Systems Engineering Technische Universität Dortmund Dortmund Germany Research Institute of Cognition & Robotics — CoR-Lab. Bielefeld University Bielefeld Germany

The infinite dimensionality, varying, uncertainties or even unknown boundary conditions render the derivation and - in particular - the identification of accurate dynamics models for elastic link robots tedious and error prone. This contribution circumvents these challenges by the prior application of a model-free inner loop oscillation damping controller before modelling the robot's dynamics. Then, the damped dynamics of a multi elastic link robot arm under gravity can be modelled with high accuracy. An analytical and a data-driven model for the damped dynamics are proposed and quantitatively compared. Both models can explain motor currents as well as link strain measurements in real-time. The paper includes an experimental model validation with different payloads in the entire workspace of the robot.

关键词： Joints Torque Strain Robots Payloads Oscillators Analytical models

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Sum of Squares Approaches for control of Continuous-Time Recurrent Fuzzy Systems

Sum of Squares Approaches for Control of Continuous-Time Rec...

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Mediterranean Conference on control & Automation

作者： Stefan Gering Andreas Schwung Thomas Gussner Jurgen Adamy Technische Universitat Darmstadt Control Theory & Robotics Lab

ISBN: (纸本)9781479909964

In recent years, a concise theory of recurrent fuzzy systems has emerged and methods for utilizing these fuzzy systems with dynamics for modeling and fault detection were developed. At the same time, sum of squares decompositions in conjunction with semidefinite programming were successfully applied for the synthesis of controllers for polynomial systems. In this paper, we combine both approaches and present sum of squares based control strategies for continuous-time recurrent fuzzy systems. The system dynamics under consideration is defined by gradients at discrete points in the input-state space. An alternative description as piecewise polynomial system is possible. This motivates to utilize a controller switching between local polynomial control laws. We propose three different approaches for controller synthesis based on this idea and demonstrate this new synthesis method by means of an example. In addition, advantages and drawbacks of the approaches are discussed.

关键词： Continuous-Time Recurrent Fuzzy Systems Sum of Squares controller Synthesis Switched controller Polynomial Systems Semidefinite Programming

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Learning associative spatiotemporal features with non-negative sparse coding

Learning associative spatiotemporal features with non-negati...

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21st European Symposium on Artificial Neural Networks, Computational Intelligence and Machine Learning, ESANN 2013

作者： Guthier, Thomas Gerges, Steve Willert, Volker Eggert, Julian TU Darmstadt Control theory and robotics lab Landgraf-Georg-Str. 4 64283 Darmstadt Germany Honda Research Institute Europe Carl-Legien-Str. 30 63073 Offenbach Germany

ISBN: (纸本)9782874190810

Motion features based on optical flow are very powerful in tasks such as the recognition of human actions or gestures. Usually, they are combined with gradient information to form a set of spatiotemporal features. However, humans can recognize gestures and actions and thus derive the implied motion out of static images alone. We model this associative recognition within a learned hierarchy of non-negative sparse coding layers. In the first stages, topology preserving gradient and motion features are processed separately. Afterwards, they are projected onto a combined inner representation, that is learned during the training phase. We show, that during recognition the learned, combined representation improves the recognition of human actions, even in the absence of explicit motion information.

关键词： Codes (symbols)

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26th Annual Computational Neuroscience Meeting (CNS*2017): Part 3 Antwerp, Belgium. 15-20 July 2017 Abstracts

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BMC NEUROSCIENCE 2017年第SUPPL 1期18卷 95-176页

作者： [Anonymous] Department of Neuroscience Yale University New Haven CT 06520 USA Department Physiology & Pharmacology SUNY Downstate Brooklyn NY 11203 USA NYU School of Engineering 6 MetroTech Center Brooklyn NY 11201 USA Departament de Matemàtica Aplicada Universitat Politècnica de Catalunya Barcelona 08028 Spain Institut de Neurobiologie de la Méditerrannée (INMED) INSERM UMR901 Aix-Marseille Univ Marseille France Center of Neural Science New York University New York NY USA Aix-Marseille Univ INSERM INS Inst Neurosci Syst Marseille France Laboratoire de Physique Théorique et Modélisation CNRS UMR 8089 Université de Cergy-Pontoise 95300 Cergy-Pontoise Cedex France Department of Mathematics and Computer Science ENSAT Abdelmalek Essaadi’s University Tangier Morocco Laboratory of Natural Computation Department of Information and Electrical Engineering and Applied Mathematics University of Salerno 84084 Fisciano SA Italy Department of Medicine University of Salerno 84083 Lancusi SA Italy Dipartimento di Fisica Università degli Studi Aldo Moro Bari and INFN Sezione Di Bari Italy Data Analysis Department Ghent University Ghent Belgium Coma Science Group University of Liège Liège Belgium Cruces Hospital and Ikerbasque Research Center Bilbao Spain BIOtech Department of Industrial Engineering University of Trento and IRCS-PAT FBK 38010 Trento Italy Department of Data Analysis Ghent University Ghent 9000 Belgium The Wellcome Trust Centre for Neuroimaging University College London London WC1N 3BG UK Department of Electronic Engineering NED University of Engineering and Technology Karachi Pakistan Blue Brain Project École Polytechnique Fédérale de Lausanne Lausanne Switzerland Departement of Mathematics Swansea University Swansea Wales UK Laboratory for Topology and Neuroscience at the Brain Mind Institute École polytechnique fédérale de Lausanne Lausanne Switzerland Institute of Mathematics University of Aberdeen Aberdeen Scotland UK Department of Integrativ

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From Grid Maps to Parametric Free Space Maps - A Highly Compact, Generic Environment Representation for ADAS

From Grid Maps to Parametric Free Space Maps - A Highly Comp...

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IEEE Intelligent Vehicles Symposium

作者： Matthias Schreier Volker Willert Jüren Adamy Institute of Automatic Control and Mechatronics Control Theory and Robotics Lab TU Darmstadt Landgraf-Georg-Str. 4 64283 Darmstadt Germany

ISBN: (纸本)9781467327534

We propose a highly compact, generic representation of the driving environment, so-called Parametric Free Space (PFS) maps, specifically suitable for future Advanced Driver Assistance Systems (ADAS) and bring them into line with existing metric representations known from mobile robotics. PFS maps combine a closed contour description of arbitrarily shaped outer free space boundaries with a representation of inner free space boundaries, respectively objects, by geometric primitives. A real-time capable algorithm is presented that obtains the representation by building upon an inermediate occupancy grid map-based environment representation generated from an automotive radar and a stereo camera. The proposed representation preserves all relevant information contained in a grid map - thus remaining function-independent - in a much more compact way, which is considered particularly important for the transmission via low data-rte automotive communication interfaces. Examples are shown in real traffic scenarios.

关键词： Grid Maps Parametric Free Space Maps Generic Environment Representation for ADAS

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Robust observer-based fault detection and isolation in the standard control problem framework

Robust observer-based fault detection and isolation in the s...

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7th IFAC Symposium on Robust control Design, ROCOND'12

作者： Wahrburg, Arne Khodaverdian, Saman Adamy, Jürgen Institute of Automatic Control Control Theory and Robotics Lab. Technische Universität Darmstadt Germany

ISBN: (纸本)9783902823038

This paper deals with the design of robust fault detection and isolation observers where only a single observer is employed to isolate different faults. To this end, the problem of parameterizing such observers is shown to be equivalent to designing a structurally constrained controller in the standard control problem framework. Thereby, the problem is reformulated as a well known classical control problem, which enables the use of existing tools to optimize robustness with respect to arbitrary exogenous disturbances. To account for parametric uncertainties, an approximate model matching approach is used. © 2012 IFAC.

关键词： Fault detection

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Robust fault isolation observers for non-square systems - A parametric approach

Robust fault isolation observers for non-square systems - A ...

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8th IFAC Symposium on Fault Detection, Supervision and Safety of Technical Processes, SAFEPROCESS 2012

作者： Wahrburg, Arne Adamy, Jürgen Institute of Automatic Control Control Theory and Robotics Lab. Technische Universität Darmstadt Germany

ISBN: (纸本)9783902823090

In this article, a linear matrix inequality (LMI)-based design for robust fault isolation observers (FIOs) for linear systems with arbitrary fault detectability indices is presented. A parametric design is used to achieve stable fault isolation in square systems as well as non-square systems. Based on this design, the influence of arbitrary disturbances is attenuated by a proper optimization of the observer gain matrices. The applicability of the proposed design is verified in simulations of a helicopter model. © 2012 IFAC.

关键词： Linear matrix inequalities

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Modeling and adaptive control of a quadrotor

Modeling and adaptive control of a quadrotor

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2012 9th IEEE International Conference on Mechatronics and Automation, ICMA 2012

作者： Schreier, Matthias Institute of Automatic Control and Mechatronics Control Theory and Robotics Lab. TU Darmstadt Landgraf-Georg-Str. 4 64283 Darmstadt Germany

ISBN: (纸本)9781467312776

In this paper, we propose two variants of adaptive state space controllers for attitude stabilization and self-tuning of a four-rotor aerial robot, a quadrotor. First of all, the use of a Model Identification Adaptive controller (MIAC) is proposed in terms of combining a recursive least-squares estimator with exponential forgetting with an integral discrete-time state space controller. Furthermore, a continuous-time Model Reference Adaptive control (MRAC) scheme based on Lyapunov theory is applied to the simplified dynamics of a quadrotor, which guarantees global asymptotic stability for at least linear overall systems. The effectiveness of the suggested adaptive methods is demonstrated in simulations with a quaternion-based nonlinear dynamic model of a quadrotor derived in this work. The results are compared to a designed nonadaptive integral state space controller. © 2012 IEEE.

关键词： Unmanned aerial vehicles (UAV)

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