Change search
Refine search result
6789 401 - 437 of 437
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 401.
    Wang, Lin
    et al.
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Optimization and Systems Theory.
    Markdahl, Johan
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Optimization and Systems Theory.
    Hu, Xiaoming
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Optimization and Systems Theory. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Wang, Xiaofan
    Position and attitude tracking for a formation of three agents2012In: Chinese Control Conference, CCC, 2012, p. 6406-6410Conference paper (Refereed)
    Abstract [en]

    In this paper we consider a trajectory tracking control problem for a multi-agent formation consisting of three agents. The agents provide a high level representation of three manipulators that have grasped a rigid object. More precisely, the agents' positions represent the end-effectors' grasp points. The agents are modelled by single integrators, and are designed to move the object such that it is located at a particular position with a particular attitude in a particular time, i.e. position and attitude tracking. The object rigidity is modelled by requiring that the agents should remain at constant relative distances from each other, reducing their three degrees of freedom each to a total of six translational and rotational degrees of freedom for the whole formation. The formation of agents is shown to be equivalent to a rigid body. The position tracking problem is solved using a standard technique whereas the attitude tracking problem is solved by adopting and adapting a recently developed approach.

  • 402. Wang, Lin
    et al.
    Wang, Xiaofan
    Hu, Xiaoming
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Optimization and Systems Theory. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Connectivity Preserving Flocking without Velocity Measurement2013In: Asian journal of control, ISSN 1561-8625, E-ISSN 1561-8625, Vol. 15, no 2, p. 521-532Article in journal (Refereed)
    Abstract [en]

    In this paper, we address the design of a decentralized controller for connectivity-preserving flocking, where each agent only can access to the position information of the agents within its sensing zone. An output vector, based on the position information alone, is constructed to replace the role of velocity, and some bounded attractive and repulsive forces are integrated together to design the controller. We prove that the controller not only synchronizes all agents in a stable formation, but also enables collision avoidance and connectivity preserving all of the time, when the initial condition meets certain requirements. Moreover, a leader-follower method is used to guide the group to a desired direction, where the followers can sense the leader only if the distance between them is less than the communication radius.

  • 403.
    Wang, Yuquan
    et al.
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP.
    Smith, Christian
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Ögren, Petter
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP.
    Karayiannidis, Ioannis
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP.
    Cooperative control of a serial-to-parallel structure using a virtual kinematic chain in a mobile dual-arm manipulation application2015In: Intelligent Robots and Systems (IROS), 2015 IEEE/RSJ International Conference on, Hamburg, Germany: IEEE Robotics and Automation Society, 2015, p. 2372-2379Conference paper (Refereed)
    Abstract [en]

    In the future mobile dual-arm robots are expected to perform many tasks. Kinematically, the configuration of two manipulators that branch from the same common mobile base results in a serial-to-parallel kinematic structure, which makes inverse kinematic computations non-trivial. The motion of the base has to be decided in a trade-off, taking the needs of both arms into account. We propose to use a Virtual Kinematic Chain (VKC) to specify the common motion of the parallel manipulators, instead of using the two manipulators kinematics directly. With this VKC, we formulate a constraint based programming solution for the robot to respond to external disturbances during task execution. The proposed approach is experimentally verified both in a noise-free illustrative simulation and a real human robot co-manipulation task.

  • 404.
    Wang, Yuquan
    et al.
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP.
    Thunberg, Johan
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Optimization and Systems Theory.
    Hu, Xiaoming
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Optimization and Systems Theory. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    A transformation of the Position Based Visual Servoing Problem into a convex optimization problem2012In: 2012 IEEE 51st Annual Conference on Decision and Control (CDC), IEEE , 2012, p. 5673-5678Conference paper (Refereed)
    Abstract [en]

    Here we address the problem of moving a camera from an initial pose to a final pose. The trajectory between the two poses is subject to constraints on the camera motion and the visibility, where we have bounds on the allowed velocities and accelerations of the camera and require that a set of point features are visible for the camera. We assume that the pose is possible to retrieve from the observations of the point features, i.e., we have a Position Based Visual Servoing Problem with constraints. We introduce a two step method that transforms the problem into a convex optimization problem with linear constraints. In the first step the rotational motion is restricted to be of a certain type. This restriction allows us to retrieve an explicit solution of the rotational motion that is optimal in terms of minimizing geodesic distance. Furthermore, this restriction guarantees that the rotational motion satisfies the constraints. Using the explicit solution, we can formulate a convex optimization problem for the translational motion, where we include constraints on workspace and visibility.

  • 405.
    Wang, Yuquan
    et al.
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Wang, Lihui
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Production Systems.
    Reactive task-oriented redundancy resolution using constraint-based programming2016In: IEEE International Conference on Intelligent Robots and Systems, IEEE, 2016, p. 5689-5694Conference paper (Refereed)
    Abstract [en]

    Constraint based programming provides a versatile framework for combining several different constraints into a single robot control scheme. We take advantage of the redundancy of a robot manipulator to improve the execution of a reactive tracking task, in terms of a task-dependent measure which is a weighted sum of velocity transmissions along the current directions of motion. With inspiration from recent work, we provide analytical gradients and computable weights of the task-dependent measure, which enable us to include it in a reactive constraint based programming framework, without relying on inexact numerical approximations and manually tuning weights. The proposed approach is illustrated in a set of simulations, comparing the performance with a standard constraint based programming method.

  • 406.
    Wang, Zhan
    et al.
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP.
    Ambrus, Rares
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP.
    Jensfelt, Patric
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS. KTH, School of Chemical Science and Engineering (CHE).
    Folkesson, John
    KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS. KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP.
    Modeling motion patterns of dynamic objectsby IOHMM2014In: Intelligent Robots and Systems (IROS 2014), 2014 IEEE/RSJ International Conference on, Chicago, IL: IEEE conference proceedings, 2014, p. 1832-1838Conference paper (Refereed)
    Abstract [en]

    This paper presents a novel approach to model motion patterns of dynamic objects, such as people and vehicles, in the environment with the occupancy grid map representation. Corresponding to the ever-changing nature of the motion pattern of dynamic objects, we model each occupancy grid cell by an IOHMM, which is an inhomogeneous variant of the HMM. This distinguishes our work from existing methods which use the conventional HMM, assuming motion evolving according to a stationary process. By introducing observations of neighbor cells in the previous time step as input of IOHMM, the transition probabilities in our model are dependent on the occurrence of events in the cell's neighborhood. This enables our method to model the spatial correlation of dynamics across cells. A sequence processing example is used to illustrate the advantage of our model over conventional HMM based methods. Results from the experiments in an office corridor environment demonstrate that our method is capable of capturing dynamics of such human living environments.

  • 407.
    Wang, Zhan
    et al.
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Jensfelt, Patric
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Folkesson, John
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Building a human behavior map from local observations2016In: Robot and Human Interactive Communication (RO-MAN), 2016 25th IEEE International Symposium on, IEEE, 2016, p. 64-70, article id 7745092Conference paper (Refereed)
    Abstract [en]

    This paper presents a novel method for classifying regions from human movements in service robots' working environments. The entire space is segmented subject to the class type according to the functionality or affordance of each place which accommodates a typical human behavior. This is achieved based on a grid map in two steps. First a probabilistic model is developed to capture human movements for each grid cell by using a non-ergodic HMM. Then the learned transition probabilities corresponding to these movements are used to cluster all cells by using the K-means algorithm. The knowledge of typical human movements for each location, represented by the prototypes from K-means and summarized in a ‘behavior-based map’, enables a robot to adjust the strategy of interacting with people according to where they are located, and thus greatly enhances its capability to assist people. The performance of the proposed classification method is demonstrated by experimental results from 8 hours of data that are collected in a kitchen environment.

  • 408.
    Wang, Zhan
    et al.
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP.
    Jensfelt, Patric
    KTH, School of Computer Science and Communication (CSC).
    Folkesson, John
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Modeling Spatial-Temporal Dynamics of Human Movements for Predicting Future Trajectories2015Conference paper (Refereed)
    Abstract [en]

    This paper presents a novel approach to modeling the dynamics of human movements with a grid-based representation. For each grid cell, we formulate the local dynamics using a variant of the left-to-right HMM, and thus explicitly model the exiting direction from the current cell. The dependency of this process on the entry direction is captured by employing the InputOutput HMM (IOHMM). On a higher level, we introduce the place where the whole trajectory originated into the IOHMM framework forming a hierarchical input structure. Therefore, we manage to capture both local spatial-temporal correlations and the long-term dependency on faraway initiating events, thus enabling the developed model to incorporate more information and to generate more informative predictions of future trajectories. The experimental results in an office corridor environment verify the capabilities of our method.

  • 409.
    Wang, Zhan
    et al.
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP.
    Jensfelt, Patric
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP.
    Folkesson, John
    KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS. KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP.
    Multi-scale conditional transition map: Modeling spatial-temporal dynamics of human movements with local and long-term correlations2015In: Intelligent Robots and Systems (IROS), 2015 IEEE/RSJ International Conference on, IEEE conference proceedings, 2015, p. 6244-6251Conference paper (Refereed)
    Abstract [en]

    This paper presents a novel approach to modeling the dynamics of human movements with a grid-based representation. The model we propose, termed as Multi-scale Conditional Transition Map (MCTMap), is an inhomogeneous HMM process that describes transitions of human location state in spatial and temporal space. Unlike existing work, our method is able to capture both local correlations and long-term dependencies on faraway initiating events. This enables the learned model to incorporate more information and to generate an informative representation of human existence probabilities across the grid map and along the temporal axis for intelligent interaction of the robot, such as avoiding or meeting the human. Our model consists of two levels. For each grid cell, we formulate the local dynamics using a variant of the left-to-right HMM, and thus explicitly model the exiting direction from the current cell. The dependency of this process on the entry direction is captured by employing the Input-Output HMM (IOHMM). On the higher level, we introduce the place where the whole trajectory originated into the IOHMM framework forming a hierarchical input structure to capture long-term dependencies. The capabilities of our method are verified by experimental results from 10 hours of data collected in an office corridor environment.

  • 410.
    Ward, Erik
    et al.
    KTH, School of Computer Science and Communication (CSC), Robotics, perception and learning, RPL.
    Evestedt, Niclas
    Linköping University .
    Axehill, Daniel
    Linköping Universtiy.
    Folkesson, John
    KTH, School of Computer Science and Communication (CSC), Robotics, perception and learning, RPL. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Probabilistic Model for Interaction Aware Planning in Merge Scenarios2017In: IEEE Transactions on Intelligent Vehicles, ISSN 2379-8858, Vol. 2, no 2, p. 133-146Article in journal (Refereed)
    Abstract [en]

    Merge scenarios confront drivers with some of the most complicated driving maneuvers in every day driving, requiring anticipatory reasoning of positions of other vehicles, and the own vehicles future trajectory. In congested traffic it might be impossible to merge without cooperation of up-stream vehicles, therefore, it is essential to gauge the effect of our own trajectory when planning a merge maneuver. For an autonomous vehicle to perform a merge maneuver in congested traffic similar capabilities are required. This includes a model describing the future evolution of the scene that allows for optimizing the autonomous vehicle's planned trajectory with respect to risk, comfort, and dynamical limitations. We present a probabilistic model that explicitly models interaction between vehicles and allows for evaluating the utility of a large number of candidate trajectories of an autonomous vehicle using a receding horizon approach in order to select an appropriate merge maneuver. The model is an extension of the intelligent driver model and the modeled behavior of other vehicles are adjusted using on-line model parameter estimation in order to give better predictions. The prediction model is evaluated using naturalistic traffic data and the merge maneuver planner is evaluated in simulation.

  • 411.
    Ward, Erik
    et al.
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP.
    Folkesson, John
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Multi-classification of Driver Intentions in Yielding Scenarios2015In: Intelligent Transportation Systems (ITSC), 2015 IEEE 18th International Conference on, IEEE , 2015, p. 678-685Conference paper (Refereed)
    Abstract [en]

    Predictions of the future motion of other vehicles in the vicinity of an autonomous vehicle is required for safe operation on trafficked roads. An important step in order to use proper behavioral models for trajectory prediction is correctly classifying the intentions of drivers. This paper focuses on recognizing the intention of drivers without priority in yielding scenarios at intersections - where the behavior of the driver depends on interaction with other drivers with priority. In these scenarios the behavior can be divided into multiple classes for which we have compared three common classification algorithms: k-nearest neighbors, random forests and support vector machines. Evaluation on a data set of tracked vehicles recorded at an unsignalized intersection show that multiple intentions can be learned and that the support vector machine algorithm exhibits superior classification performance.

  • 412.
    Ward, Erik
    et al.
    KTH, School of Computer Science and Communication (CSC).
    Folkesson, John
    KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS. KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP.
    Vehicle localization with low cost radar sensors2016In: Intelligent Vehicles Symposium (IV), 2016 IEEE, Institute of Electrical and Electronics Engineers (IEEE), 2016Conference paper (Refereed)
    Abstract [en]

    Autonomous vehicles rely on GPS aided by motion sensors to localize globally within the road network. However, not all driving surfaces have satellite visibility. Therefore, it is important to augment these systems with localization based on environmental sensing such as cameras, lidar and radar in order to increase reliability and robustness. In this work we look at using radar for localization. Radar sensors are available in compact format devices well suited to automotive applications. Past work on localization using radar in automotive applications has been based on careful sensor modeling and Sequential Monte Carlo, (Particle) filtering. In this work we investigate the use of the Iterative Closest Point, ICP, algorithm together with an Extended Kalman filter, EKF, for localizing a vehicle equipped with automotive grade radars. Experiments using data acquired on public roads shows that this computationally simpler approach yields sufficiently accurate results on par with more complex methods.

  • 413. Wei, A.
    et al.
    Wang, Y.
    Hu, Xiaoming
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Optimization and Systems Theory. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Adaptive robust parallel simultaneous stabilization of two uncertain port-controlled Hamiltonian systems subject to input saturation2012In: Chinese Control Conference, CCC, IEEE , 2012, p. 727-732Conference paper (Refereed)
    Abstract [en]

    This paper deals with the problem of adaptive robust parallel simultaneous stabilization(ARPSS) of two uncertain nonlinear port-controlled Hamiltonian systems subject to input saturation, and proposes a number of results on the control design. Firstly, an adaptive H∞ control design approach is presented by using both the dissipative Hamiltonian structural and saturated actuator properties for the case that there are both parametric uncertainties and external disturbances in the systems. Secondly, the results obtained for Hamiltonian systems are applied to ARPSS problem for two uncertain nonlinear affine systems subject to input saturation, and several interesting results are obtained. Finally, study of an example with simulations shows that the adaptive controller proposed in this paper is effective.

  • 414. Wei, Airong
    et al.
    Hu, Xiaoming
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Optimization and Systems Theory. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Wang, Yuzhen
    Consensus of Linear Multi-Agent Systems Subject to Actuator Saturation2013In: International Journal of Control, Automation and Systems, ISSN 1598-6446, E-ISSN 2005-4092, Vol. 11, no 4, p. 649-656Article in journal (Refereed)
    Abstract [en]

    This paper is aimed at studying the consensus of linear multi-agent systems subject to actuator saturation. In order to solve the consensus problem, a new family of scheduled low-and-high-gain decentralized control laws are designed, provided that the dynamics of each agent is asymptotically null controllable with bounded controls, and such control laws rely on the asymptotic property of a class of parametric algebraic Ricatti equations. It is shown that the consensus of the systems with connected and fixed topology can be achieved semi-globally asymptotically via the local error low-and-high-gain feedback. An illustrative example with simulations shows that our method as well as control protocols is effective for the consensus of the linear multi-agent systems subject to actuator saturation.

  • 415. Wei, Airong
    et al.
    Wang, Yuzhen
    Hu, Xiaoming
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Optimization and Systems Theory. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Adaptive simultaneous stabilization of two Port-Controlled Hamiltonian systems subject to actuator saturation2012In: Intelligent Control and Automation (WCICA), 2012 10th World Congress on, IEEE , 2012, p. 1767-1772Conference paper (Refereed)
    Abstract [en]

    This paper investigates the adaptive parallel simultaneous stabilization (APSS) of two multi-input nonlinear Port-Controlled Hamiltonian (PCH) systems subject to actuator saturation, and proposes a number of results on the design of the APSS controllers. Using both the dissipative Hamiltonian structural and saturated actuator properties, the two systems are combined to generate an augmented PCH system subject to actuator saturation, with which some results on the control designs are then obtained. Study of an illustrative example with simulations shows that the APSS controller obtained in this paper is effective.

  • 416.
    Wei, Airong
    et al.
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Optimization and Systems Theory.
    Wang, Yuzhen
    Hu, Xiaoming
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Optimization and Systems Theory. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Estimate of Domain of Attraction for a Class of Port-Controlled Hamiltonian Systems Subject to Both Actuator Saturation and Disturbances2012In: Asian journal of control, ISSN 1561-8625, E-ISSN 1561-8625, Vol. 14, no 4, p. 1108-1112Article in journal (Refereed)
    Abstract [en]

    This paper investigates the estimate of domain of attraction for a class of nonlinear port-controlled Hamiltonian (PCH) systems subject to both actuator saturation and disturbances. Firstly, two conditions are established to determine whether an ellipsoid is contractively invariant for the systems only with actuator saturation, with which the biggest ellipsoid contained in the domain of attraction can be found. Secondly, the obtained conditions are extended to estimate the domain of attraction of the systems subject to both actuator saturation and disturbances. Study of illustrative example shows the effectiveness of the method proposed in this paper.

  • 417.
    Welle, Michael
    et al.
    KTH, School of Computer Science and Communication (CSC), Robotics, perception and learning, RPL. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Ericson, Ludvig
    KTH, School of Computer Science and Communication (CSC), Robotics, perception and learning, RPL. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Ambrus, Rares
    KTH, School of Computer Science and Communication (CSC), Robotics, perception and learning, RPL. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Jensfelt, Patric
    KTH, School of Computer Science and Communication (CSC), Robotics, perception and learning, RPL. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    On the use of Unmanned Aerial Vehicles for Autonomous Object Modeling2017In: 2017 European Conference on Mobile Robots, ECMR 2017, Institute of Electrical and Electronics Engineers (IEEE), 2017, article id 8098656Conference paper (Refereed)
    Abstract [en]

    In this paper we present an end to end object modeling pipeline for an unmanned aerial vehicle (UAV). We contribute a UAV system which is able to autonomously plan a path, navigate, acquire views of an object in the environment from which a model is built. The UAV does collision checking of the path and navigates only to those areas deemed safe. The data acquired is sent to a registration system which segments out the object of interest and fuses the data. We also show a qualitative comparison of our results with previous work.

  • 418. Wyatt, Jeremy L.
    et al.
    Aydemir, Alper
    KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS. KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP.
    Brenner, Michael
    Hanheide, Marc
    Hawes, Nick
    Jensfelt, Patric
    KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS. KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP.
    Kristan, Matej
    Kruijff, Geert-Jan M.
    Lison, Pierre
    Pronobis, Andrzej
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Sjöö, Kristoffer
    KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS. KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP.
    Vrecko, Alen
    Zender, Hendrik
    Zillich, Michael
    Skocaj, Danijel
    Self-Understanding and Self-Extension: A Systems and Representational Approach2010In: IEEE T AUTON MENT DE, ISSN 1943-0604, Vol. 2, no 4, p. 282-303Article in journal (Refereed)
    Abstract [en]

    There are many different approaches to building a system that can engage in autonomous mental development. In this paper, we present an approach based on what we term self-understanding, by which we mean the explicit representation of and reasoning about what a system does and does not know, and how that knowledge changes under action. We present an architecture and a set of representations used in two robot systems that exhibit a limited degree of autonomous mental development, which we term self-extension. The contributions include: representations of gaps and uncertainty for specific kinds of knowledge, and a goal management and planning system for setting and achieving learning goals.

  • 419.
    Xiao, Shuang
    et al.
    KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Wang, Zhan
    KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Folkesson, John
    KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS. KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP.
    Unsupervised robot learning to predict person motion2015In: Proceedings - IEEE International Conference on Robotics and Automation, IEEE conference proceedings, 2015, no June, p. 691-696Conference paper (Refereed)
    Abstract [en]

    Socially interacting robots will need to understand the intentions and recognize the behaviors of people they come in contact with. In this paper we look at how a robot can learn to recognize and predict people's intended path based on its own observations of people over time. Our approach uses people tracking on the robot from either RGBD cameras or LIDAR. The tracks are separated into homogeneous motion classes using a pre-trained SVM. Then the individual classes are clustered and prototypes are extracted from each cluster. These are then used to predict a person's future motion based on matching to a partial prototype and using the rest of the prototype as the predicted motion. Results from experiments in a kitchen environment in our lab demonstrate the capabilities of the proposed method.

  • 420.
    Xing, Li
    et al.
    KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Pronobis, Andrzej
    KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS. KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP.
    Multi-cue Discriminative Place Recognition2010In: MULTILINGUAL INFORMATION ACCESS EVALUATION II: MULTIMEDIA EXPERIMENTS, PT II / [ed] Peters C; Caputo B; Gonzalez J; Jones GJF; KalpathyCramer J; Muller H; Tsikrika T, 2010, Vol. 6242, p. 315-323Conference paper (Refereed)
    Abstract [en]

    In this paper we report on our successful participation in the Robot Vision challenge in the ImageCLEF 2009 campaign. We present a place recognition system that employs four different discriminative models trained on different global and local visual cues. In order to provide robust recognition, the outputs generated by the models are combined using a discriminative accumulation method. Moreover, the system is able to provide an indication of the confidence of its decision. We analyse the properties and performance of the system on the training and validation data and report the final score obtained on the test run which ranked first in the obligatory track of the Robot Vision task.

  • 421.
    Xiong, Ning
    et al.
    KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Christensen, Henrik
    KTH, School of Computer Science and Communication (CSC), Numerical Analysis and Computer Science, NADA. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Svensson, Per
    Agent negotiation of target distribution enhancing system survivability2007In: International Journal of Intelligent Systems, ISSN 0884-8173, E-ISSN 1098-111X, Vol. 22, no 12, p. 1251-1269Article in journal (Refereed)
    Abstract [en]

    This article proposes an agent negotiation model for target distribution across a set of geographically dispersed sensors. The key idea is to consider sensors as autonomous agents that negotiate over the division of tasks among them for obtaining better payoffs. The negotiation strategies for agents are established based upon the concept of subgame perfect equilibrium from game theory. Using such negotiation leads to not only superior measuring performance from a global perspective but also possibly balanced allocations of tasks to sensors, benefiting system robustness and survivability. A simulation test and results are given to demonstrate the ability of our approach in improving system security while keeping overall measuring performance near optimal.

  • 422.
    Xiong, Ning
    et al.
    KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Christensen, Henrik
    KTH, School of Computer Science and Communication (CSC), Numerical Analysis and Computer Science, NADA. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Svensson, Per
    Reactive tuning of target estimate accuracy in multisensor data fusion2007In: Cybernetics and systems, ISSN 0196-9722, E-ISSN 1087-6553, Vol. 38, no 1, p. 83-103Article in journal (Refereed)
    Abstract [en]

    Dealing with conflicting and target-specific requirements is an important issue in multisensor and multitarget tracking. This paper aims to allocate sensing resources among various targets in reaction to individual information requests. The proposed approach is to introduce agents for every relevant target responsible for its tracking. Such agents are expected to bargain with each other for a division of resources. A bilateral negotiation model is established for resource allocation in two-target tracking. The applications of agent negotiation to target covariance tuning are illustrated together with simulation results presented. Moreover, we suggest a way of organizing simultaneous one-to-one negotiations, making our negotiation model still applicable in scenarios of tracking more than two targets.

  • 423.
    Yang, Yuecheng
    et al.
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Optimization and Systems Theory.
    Dimarogonas, Dimos V.
    KTH, School of Electrical Engineering (EES), Automatic Control.
    Hu, Xiaoming
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Optimization and Systems Theory. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Opinion consensus of modified Hegselmann-Krause models2012In: 2012 IEEE 51st Annual Conference on Decision and Control (CDC), IEEE , 2012, p. 100-105Conference paper (Refereed)
    Abstract [en]

    We consider the opinion consensus problem using a multi-agent setting based on the Hegselmann-Krause (H-K) Model. Firstly, we give a sufficient condition on the initial opinion distribution so that the system will converge to only one cluster. Then, modified models are proposed to guarantee convergence for more general initial conditions. The overall connectivity is maintained with these models, while the loss of certain edges can occur. Furthermore, a smooth control protocol is provided to avoid the difficulties that may arise due to the discontinuous right-hand side in the H-K model.

  • 424.
    Yang, Yuecheng
    et al.
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Optimization and Systems Theory. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Dimarogonas, Dimos V.
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Hu, Xiaoming
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Optimization and Systems Theory. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Opinion consensus of modified Hegselmann-Krause models2014In: Automatica, ISSN 0005-1098, E-ISSN 1873-2836, Vol. 50, no 2, p. 622-627Article in journal (Refereed)
    Abstract [en]

    We consider the opinion consensus problem using a multi-agent setting based on the Hegselmann-Krause (H-K) Model. Firstly, we give a sufficient condition on the initial opinion distribution so that the system will converge to only one cluster. Then, modified models are proposed to guarantee convergence for more general initial conditions. The overall connectivity is maintained with these models, while the loss of certain edges can occur. Furthermore, a smooth control protocol is provided to avoid the difficulties that may arise due to the discontinuous right-hand side in the H-K model.

  • 425.
    Zambelli, Martina
    et al.
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Karayiannidis, Yiannis
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Dimarogonas, Dimos V.
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Posture regulation for unicycle-like robots with prescribed performance guarantees2015In: IET Control Theory & Applications, ISSN 1751-8644, E-ISSN 1751-8652, Vol. 9, no 2, p. 192-202Article in journal (Refereed)
    Abstract [en]

    This study aims to address the regulation problem for the unicycle model while guaranteeing prescribed performance. Different controllers based either on polar coordinates or time-varying laws are proposed. The main contribution is the combination of the standard control laws that allow to achieve posture regulation for the unicycle, with the prescribed performance control technique that imposes time-varying constraints to the system coordinates. To apply prescribed performance to the unicycle system which is subject to a non-holonomic constraint, the authors design a specific transformation function that is instrumental in the proof of asymptotic convergence with prescribed guaranties.

  • 426.
    Zarubin, Dmitry
    et al.
    Universität Stuttgart.
    Pokorny, Florian T.
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Song, Dan
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Toussaint, Marc
    Universität Stuttgart.
    Kragic, Danica
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Topological Synergies for Grasp Transfer2013In: Hand Synergies - how to tame the complexity of grapsing: Workshop, IEEE International Conference on Robotics and Automation (ICRA 2013), 2013Conference paper (Refereed)
    Abstract [en]

    In this contribution, we propose a novel approach towards representing physically stable grasps which enables us to transfer grasps between different hand kinematics. We use a low dimensional topologically inspired coordinate representation which we call topological synergies, and which is motivated by the topological notion of winding numbers. We address the transfer problem as a stochastic optimization task and carry out motion planning in our topologically inspired coordinates using the Approximate Inference Control (AICO) framework. This perspective allows us to compute not only the final grasp itself, but also a trajectory in configuration space leading to it. We evaluate our approach using the simulation framework PhysX. The presented experiments, which develop further recent attempts to use topologically inspired coordinates in robotics, demonstrate that our approach makes it possible to transfer a large percentage of grasps between a simulated human hand and a 3-finger Schunk hand.

  • 427.
    Zarubin, Dmitry
    et al.
    Universität Stuttgart.
    Pokorny, Florian T.
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Toussaint, Marc
    Universität Stuttgart.
    Kragic, Danica
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Caging Complex Objects with Geodesic Balls2013In: Proceedings of the 2013 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2013), IEEE , 2013, p. 2999-3006Conference paper (Refereed)
    Abstract [en]

    This paper proposes a novel approach for the synthesis of grasps of objects whose geometry can be observed only in the presence of noise. We focus in particular on the problem of generating caging grasps with a realistic robot hand simulation and show that our method can generate such grasps even on complex objects. We introduce the idea of using geodesic balls on the object's surface in order to approximate the maximal contact surface between a robotic hand and an object. We define two types of heuristics which extract information from approximate geodesic balls in order to identify areas on an object that can likely be used to generate a caging grasp. Our heuristics are based on two scoring functions. The first uses winding angles measuring how much a geodesic ball on the surface winds around a dominant axis, while the second explores using the total discrete Gaussian curvature of a geodesic ball to rank potential caging postures. We evaluate our approach with respect to variations in hand kinematics, for a selection of complex real-world objects and with respect to its robustness to noise.

  • 428. Zender, H.
    et al.
    Jensfelt, Patric
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Kruijff, G.-J. M.
    Human- and Situation-Aware People Following2007In: 2007 RO-MAN: 16TH IEEE INTERNATIONAL SYMPOSIUM ON ROBOT AND HUMAN INTERACTIVE COMMUNICATION, VOLS 1-3, 2007, p. 1124-1129Conference paper (Refereed)
    Abstract [en]

    The paper presents an approach to intelligent, interactive people following for autonomous robots. The approach combines robust methods for simultaneous localization and mapping and for people tracking in order to yield a socially and environmentally sensitive people following behavior. Unlike current purely reactive approaches ("nearest point following") it enables the robot to follow a human in a socially acceptable way, providing verbal and non-verbal feedback to the user where necessary. At the same time, the robot makes use of information about the spatial and functional organization of its environment, so that it can anticipate likely actions performed by a human, and adjust its motion accordingly. As a result, the robot's behaviors become less reactive and more intuitive when following people around an indoor environment. The approach has been fully implemented and tested.

  • 429. Zender, H.
    et al.
    Jensfelt, Patric
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Mozos, O. M.
    Kruijff, G.-J. M.
    Burgard, W.
    An integrated robotic system for spatial understanding and situated interaction in indoor environments2007In: AAAI-07/IAAI-07 Proceedings: 22nd AAAI Conference on Artificial Intelligence and the 19th Innovative Applications of Artificial Intelligence Conference, 2007, p. 1584-1589Conference paper (Refereed)
    Abstract [en]

    A major challenge in robotics and artificial intelligence lies in creating robots that are to cooperate with people in human-populated environments, e.g. for domestic assistance or elderly care. Such robots need skills that allow them to interact with the world and the humans living and working therein. In this paper we investigate the question of spatial understanding of human-made environments. The functionalities of our system comprise perception of the world, natural language, learning, and reasoning. For this purpose we integrate state-of-the-art components from different disciplines in AI, robotics and cognitive systems into a mobile robot system. The work focuses on the description of the principles we used for the integration, including cross-modal integration, ontology-based mediation, and multiple levels of abstraction of perception. Finally, we present experiments with the integrated “CoSy Explorer ” 1 system and list some of the major lessons that were learned from its design, implementation, and evaluation.

  • 430. Zender, H.
    et al.
    Mozos, O. Martinez
    Jensfelt, Patric
    KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS. KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP.
    Kruijff, G. J. M.
    Burgard, W.
    Conceptual spatial representations for indoor mobile robots2008In: Robotics and Autonomous Systems, ISSN 0921-8890, E-ISSN 1872-793X, Vol. 56, no 6, p. 493-502Article in journal (Refereed)
    Abstract [en]

    We present an approach for creating conceptual representations of human-made indoor environments using mobile robots. The concepts refer to spatial and functional properties of typical indoor environments. Following different findings in spatial cognition, our model is composed of layers representing maps at different levels of abstraction. The complete system is integrated in a mobile robot endowed with laser and vision sensors for place and object recognition. The system also incorporates a linguistic framework that actively supports the map acquisition process, and which is used for situated dialogue. Finally, we discuss the capabilities of the integrated system.

  • 431.
    Zhang, Cheng
    et al.
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Ek, Carl Henrik
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Gratal, Xavi
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Pokorny, Florian T.
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Kjellström, Hedvig
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Supervised Hierarchical Dirichlet Processes with Variational Inference2013In: 2013 IEEE International Conference on Computer Vision Workshops (ICCVW), IEEE , 2013, p. 254-261Conference paper (Refereed)
    Abstract [en]

    We present an extension to the Hierarchical Dirichlet Process (HDP), which allows for the inclusion of supervision. Our model marries the non-parametric benefits of HDP with those of Supervised Latent Dirichlet Allocation (SLDA) to enable learning the topic space directly from data while simultaneously including the labels within the model. The proposed model is learned using variational inference which allows for the efficient use of a large training dataset. We also present the online version of variational inference, which makes the method scalable to very large datasets. We show results comparing our model to a traditional supervised parametric topic model, SLDA, and show that it outperforms SLDA on a number of benchmark datasets.

  • 432.
    Zhang, Cheng
    et al.
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Song, Dan
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Kjellström, Hedvig
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Contextual Modeling with Labeled Multi-LDA2013In: 2013 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), IEEE , 2013, p. 2264-2271Conference paper (Refereed)
    Abstract [en]

    Learning about activities and object affordances from human demonstration are important cognitive capabilities for robots functioning in human environments, for example, being able to classify objects and knowing how to grasp them for different tasks. To achieve such capabilities, we propose a Labeled Multi-modal Latent Dirichlet Allocation (LM-LDA), which is a generative classifier trained with two different data cues, for instance, one cue can be traditional visual observation and another cue can be contextual information. The novel aspects of the LM-LDA classifier, compared to other methods for encoding contextual information are that, I) even with only one of the cues present at execution time, the classification will be better than single cue classification since cue correlations are encoded in the model, II) one of the cues (e.g., common grasps for the observed object class) can be inferred from the other cue (e.g., the appearance of the observed object). This makes the method suitable for robot online and transfer learning; a capability highly desirable in cognitive robotic applications. Our experiments show a clear improvement for classification and a reasonable inference of the missing data.

  • 433. Zhong, J.
    et al.
    Karasalo, M.
    Cheng, D.
    Hu, Xiaoming
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Optimization and Systems Theory. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    New results on non-regular linearization of non-linear systems2007In: International Journal of Control, ISSN 0020-7179, E-ISSN 1366-5820, Vol. 80, no 10, p. 1651-1664Article in journal (Refereed)
    Abstract [en]

    This paper presents some new results on non-regular linearization of non-linear systems. Based on a normal form and a non-regular linearization technique developed recently, the paper first provides a set of calculating formulas for the linearization procedure. As an application, the linearization of bilinear systems is investigated. Then, it presents easily veri. able sufficient conditions for the global (semi-global) (approximate) linearization. Finally, an estimate of the region of attraction for the kth degree approximately linearized systems with state feedback control is given, which illustrates one of the advantages of the approximate linearization.

  • 434. Zhong, Jianghua
    et al.
    Cheng, Daizhan
    Hu, Xiaoming
    KTH, School of Engineering Sciences (SCI), Mathematics (Dept.), Optimization and Systems Theory. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Constructive stabilization for quadratic input nonlinear systems2008In: Automatica, ISSN 0005-1098, E-ISSN 1873-2836, Vol. 44, no 8, p. 1996-2005Article in journal (Refereed)
    Abstract [en]

    In this paper stabilization of nonlinear systems with quadratic multi-input is considered. With the help of control Lyapunov function (CLF), a constructive parameterization of controls that globally asymptotically stabilize the system is proposed. Two different cases are considered. Firstly, under certain regularity assumptions. the feasible control set is parameterized, and Continuous feedback stabilizing controls are designed. Then for the general case. piecewise Continuous stabilizing controls are proposed. The design procedure can also be used to verify whether a candidate CLF is indeed a CLF. Several illustrative examples are presented as well.

  • 435. Zivkovic, Zoran
    et al.
    Booij, Olaf
    Kröse, Ben
    Topp, Elin Anna
    KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Christensen, Henrik I.
    KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    From sensors to human spatial concepts: An annotated data set2008In: IEEE Transactions on Robotics, ISSN 1552-3098, Vol. 24, no 2, p. 501-505Article in journal (Refereed)
    Abstract [en]

    An annotated data set is presented meant to help researchers in developing, evaluating, and comparing various approaches in robotics for building space representations appropriate for communicating with humans. The data consist of omnidirectional images, laser range scans, sonar readings, and robot odometry. A set of base-level human spatial concepts is used to annotate the data.

  • 436.
    Ótão Pereira, Pedro Miguel
    et al.
    KTH, School of Electrical Engineering (EES), Automatic Control.
    Dimarogonas, Dimos V.
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Stability of load lifting by a quadrotor under attitude control delay2017In: Proceedings - IEEE International Conference on Robotics and Automation, Institute of Electrical and Electronics Engineers Inc. , 2017, p. 3287-3292Conference paper (Refereed)
    Abstract [en]

    We propose a control law for stabilization of a quadrotor-load system, and provide conditions on the control law's gains that guarantee exponential stability of the equilibrium. The system is composed of a load and an unmanned aerial vehicle (UAV) attached to each other by a cable of fixed length, which behaves as a rigid link under tensile forces; and the control input is composed of a three dimensional force requested to the UAV, which the UAV provides with or without delay. Given the proposed control law, we analyze the stability of the equilibrium in two separate parts. In the first, the system is modeled assuming that the UAV provides the requested control input without delay, and we verify that the equilibrium is exponentially stable. In the second part, the UAV is modeled as possessing an attitude inner loop, and we provide a lower bound on the attitude gain for which exponential stability of the equilibrium is preserved. An integral action term is also included in the control law, which compensates for battery drainage or model mismatches, such as an unknown load mass. We present experiments for different scenarios that demonstrate and validate the robustness of the proposed control law.

  • 437.
    Ögren, Petter
    et al.
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP. KTH, School of Computer Science and Communication (CSC), Centres, Centre for Autonomous Systems, CAS.
    Svenmarck, Peter
    FOI.
    Lif, Patric
    FOI.
    Norberg, Martin
    FOI.
    Söderbäck, Nils Emil
    Swedish Defence Research Agency (FOI).
    Design and implementation of a new teleoperation control mode for differential drive UGVs2014In: Autonomous Robots, ISSN 0929-5593, E-ISSN 1573-7527, Vol. 37, no 1, p. 71-79Article in journal (Refereed)
    Abstract [en]

    In this paper, we propose and implement a new control mode for teleoperated unmanned ground vehicles (UGVs), that exploits the similarities between computer games and teleoperation robotics. Today, all teleoperated differential drive UGVs use a control mode called Tank Control, in which the UGV chassis and the pan tilt camera are controlled separately. This control mode was also the dominating choice when the computer game genre First Person Shooter (FPS) first appeared. However, the hugely successful FPS genre, including titles such as Doom, Half Life and Call of Duty, now uses a much more intuitive control mode, Free Look Control (FLC), in which rotation and translation of the character are decoupled, and controlled separately. The main contribution of this paper is that we replace Tank Control with FLC in a real UGV. Using feedback linearization, the orientation of the UGV chassis is abstracted away, and the orientation and translation of the camera are decoupled, enabling the operator to use FLC when controlling the UGV. This decoupling is then experimentally verified. The developments in the gaming community indicates that FLC is more intuitive than Tank Control and reduces the well known situational awareness problem. It furthermore reduces the need for operator training, since literary millions of future operators have already spent hundreds of hours using the interface.

6789 401 - 437 of 437
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf