| 1. |
- Aarno, Daniel, et al.
(författare)
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Artificial potential biased probabilistic roadmap method
- 2004
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Ingår i: 2004 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1- 5, PROCEEDINGS. - 0780382323 ; , s. 461-466
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Konferensbidrag (refereegranskat)abstract
- Probabilistic roadmap methods (PRMs) have been successfully used to solve difficult path planning problems but their efficiency is limited when the free space contains narrow passages through which the robot must pass. This paper presents a new sampling scheme that aims to increase the probability of finding paths through narrow passages. Here, a biased sampling scheme is used to increase the distribution of nodes in narrow regions of the free space. A partial computation of the artificial potential field is used to bias the distribution of nodes.
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| 2. |
- Althaus, Philipp, et al.
(författare)
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Navigation for human-robot interaction tasks
- 2004
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Ingår i: 2004 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1- 5, PROCEEDINGS. - 0780382323 ; , s. 1894-1900
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Konferensbidrag (refereegranskat)abstract
- One major design goal in human-robot interaction is that the robots behave in an intelligent manner, preferably in a similar way as humans. This constraint must also be taken into consideration when the navigation system for the platform is developed. However, research in human-robot interaction is often restricted to other components of the system including gestures, manipulation, and speech. On the other hand, research for mobile robot navigation focuses primarily on the task of reaching a certain goal point in an environment. We believe that these two problems can not be treated separately for a personal robot that coexists with humans in the same surrounding. Persons move constantly while they are interacting with each other. Hence, also a robot should do that, which poses constraints on the navigation system. This type of navigation is the focus of this paper. Methods have been developed for a robot to join a group of people engaged in a conversation. Preliminary results show that the platform's moving patterns are very similar to the ones of the persons. Moreover, this dynamic interaction has been judged naturally by the test subjects, which greatly increases the perceived intelligence of the robot.
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| 3. |
- Christensen, Henrik Iskov
(författare)
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The curse of JDL
- 2004
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Ingår i: Proc. Seventh Int. Conf. Inf. Fusion. - 917056115X ; , s. 528-529
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Konferensbidrag (refereegranskat)abstract
- The JDL model provides a methodology for organisation of research infusion, it is however, important to recognize that it does not provide an architectural framework for design of systems, and as such there may be complex interaction between levels in the JDL model, which is not directly captured by the model. A reductionistic approach to research in which each of the layers are considered independently might be a danger of not showing the real complexity of information fusion systems.
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| 4. |
- Christensen, Henrik I, et al.
(författare)
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Vision for Interaction
- 2000
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Ingår i: Dagstuhl Seminars. - Berlin, Heidelberg : Springer Berlin Heidelberg. ; , s. 51-73
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Bokkapitel (refereegranskat)
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| 5. |
- Christensen, Henrik, et al.
(författare)
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UGV technology for urban navigation
- 2004
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Ingår i: UNMANNED GROUND VEHICLE TECHNOLOGY VI. - BELLINGHAM : SPIE-INT SOC OPTICAL ENGINEERING. - 0819453455 ; , s. 191-197
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Konferensbidrag (refereegranskat)abstract
- Deployment of humans in an urban setting for search and rescue type missions poses a major risk to the personnel. In rescue missions the risk can stem from debris, gas, etc and in a strategic setting the risk can stem from snipers, mines, gas etc. There is consequently a natural interest in studies of how UGV technology can be deployed for tasks such as reconnaissance, retrieval of objects (bombs, injured people, etc.). Today most vehicles used by the military and bomb squads are tele-operated and without any autonomy. This implies that operation of the vehicles is a stressful and demanding task. Part of this stress can be removed through introduction of autonomous functionality. Autonomy implicitly requires use of map information to allow the system to localize and traverse a particular area, in addition autonomous mapping of an area is a valuable functionality as part of reconnaissance missions to provide an initial inventory of a new area. A host of different sensory modalities can be used for mapping. In general no single modality is, however, sufficient for robust and efficient mapping. In the present study GPS, Inertial Cues, Laser ranging and Odometry is used for simultaneous mapping and localisation in urban environments. The mapping is carried out autonomously using a coverage strategy to ensure full mapping of a particular area. In relation to mapping another important issue is the design of an efficient user interface that allows a regular rescue worker, or a soldier, to operate the vehicle without detailed knowledge about robotics. A number of different designs for user interfaces will be presented and results from studies with a range of end-users (soldiers) will also be reported. The complete system has been tested in an urban warfare facility outside of Stockholm. Detailed results will be reposted from two different test facilities.
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| 6. |
- Edén, Johan, et al.
(författare)
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Local straightness : A contrast independent statistical edge measure for color and gray level images
- 2004
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Ingår i: PROCEEDINGS OF THE 17TH INTERNATIONAL CONFERENCE ON PATTERN RECOGNITION, VOL 2. - 0769521282 ; , s. 451-454
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Konferensbidrag (refereegranskat)abstract
- Most existing methods for edge detection rely on contrast dependent thresholds. We show that a local measurement defined by the ratio of the smallest to the largest eigenvalue of the second moment matrix of filter kernels, can be used to separate smooth, low curvature curves and straight lines from noise, independent of contrast, in both color and gray level images. This is done without applying a threshold to the gradient magnitude. The edge images are defined as zero crossings in the gradient direction. The covariance matrix can easily be computed for both gray level images and color images. Further we show the potentiality of such a measure by integrating it with the Hough transform to extract long straight lines in noisy color images. The method is shown to successfully extract consistent line features from color images of a scene, captured under drastically different lightening conditions.
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| 7. |
- Elfwing, Stefan, et al.
(författare)
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Multi-Agent Reinforcement Learning : Using Macro Actions to Learn a Mating Task
- 2004
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Ingår i: 2004 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS); Sendai. - 0780384636 ; , s. 3164-3169
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Konferensbidrag (refereegranskat)abstract
- Standard reinforcement learning methods are inefficient and often inadequate for learning cooperative multi-agent tasks. For these kinds of tasks the behavior of one agent strongly depends on dynamic interaction with other agents, not only with the interaction with a static environment as in standard reinforcement learning. The success of the learning is therefore coupled to the agents' ability to predict the other agents' behaviors. In this study we try to overcome this problem by adding a few simple macro actions, actions that are extended in time for more than one time step. The macro actions improve the learning by making search of the state space more effective and thereby making the behavior more predictable for the other agent. In this study we have considered a cooperative mating task, which is the first step towards our aim to perform embodied evolution, where the evolutionary selection process is an integrated part of the task. We show, in simulation and hardware, that in the case of learning without macro actions, the agents fail to learn a meaningful behavior. In contrast, for the learning with macro action the agents learn a good mating behavior in reasonable time, in both simulation and hardware.
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| 8. |
- Folkesson, John, 1960-, et al.
(författare)
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Graphical SLAM : a self-correcting map
- 2004
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Ingår i: 2004 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, PROCEEDINGS. - 0780382323 ; , s. 383-390
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Konferensbidrag (refereegranskat)abstract
- We describe an approach to simultaneous localization and mapping, SLAM. This approach has the highly desirable property of robustness to data association errors. Another important advantage of our algorithm is that non-linearities are computed exactly, so that global constraints can be imposed even if they result in large shifts to the map. We represent the map as a graph and use the graph to find an efficient map update algorithm. We also show how topological consistency can be imposed on the map, such as, closing a loop. The algorithm has been implemented on an outdoor robot and we have experimental validation of our ideas. We also explain how the graph can be simplified leading to linear approximations of sections of the map. This reduction gives us a natural way to connect local map patches into a much larger global map.
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| 9. |
- Folkesson, John, 1960-, et al.
(författare)
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Outdoor exploration and SLAM using a compressed filter
- 2003
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Ingår i: Proceedings - IEEE International Conference on Robotics and Automation. - 0780377362 ; , s. 419-427
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Konferensbidrag (refereegranskat)abstract
- In this paper we describe the use of automatic explorationfor autonomous mapping of outdoor scenes. We describe areal-time SLAM implementation along with an autonomous explorationalgorithm. We have implemented SLAM with a compressedextended Kalman filter (CEKF) on an outdoor robot. Our implementationuses walls of buildings as features. The state predictions aremade by using a combination of odometry and inertial data. The systemwas tested on a 200 x 200 m site with 18 buildings on variableterrain. The paper helps explain some of the implementation detailsof the compressed filter such as, how to organize the map as well asmore general issues like, how to include the effects of pitch and rolland efficient feature detection.
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| 10. |
- Folkesson, John, et al.
(författare)
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Robust SLAM
- 2004
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Ingår i: IAV-2004.
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Konferensbidrag (refereegranskat)
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| 11. |
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| 12. |
- Kragic, Danica, et al.
(författare)
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A Framework for Visual Servoing
- 2003
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Ingår i: International Conference on Computer Vision Systems. - Berlin, Heidelberg : Springer-Verlag Berlin. ; , s. 345-354
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Bokkapitel (refereegranskat)abstract
- . A general framework for visual servoing tasks is proposed. The objective of the paper is twofold: a) how a complicated servoing task might be composed from a multitude of simple ones, and b) how the integration of basic and simple visual algorithms can be used in order to provide a robust input estimate to a control loop for a mobile platform or a robot manipulator. For that purpose, voting schema and consensus theory approaches are investigated together with some initial vision based algorithms. Voting is known as a model--free approach to integration and therefore interesting for applications in real--world environments which are difficult to model. It is experimentally shown how servoing tasks like pick--and--place, opening doors and fetching mail can be robustly performed using the proposed approach. 1. Introduction In the field of service robotics, robots should continuously interact with objects and human beings in a natural, unstructured and dynamic environment. In ...
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| 13. |
- Kragic, Danica, et al.
(författare)
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Issues and Strategies for Robotic Object Manipulation in Domestic Settings
- 2004
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Many robotic tasks such as autonomous navigation,human-machine collaboration, object manipulationand grasping facilitate visual information. Some of themajor reasearch and system design issues in terms of visualsystems are robustness and flexibility.In this paper, we present a number of visual strategiesfor robotic object manipulation tasks in natural, domesticenvironments. Given a complex fetch-and-carry type oftasks, the issues related to the whole detect-approachgrasploop are considered. Our vision system integratesa number of algorithms using monocular and binocularcues to achieve robustness in realistic settings. The cuesare considered and used in connection to both foveal andperipheral vision to provide depth information, segmentthe object(s) of interest in the scene, object recognition,tracking and pose estimation. One important propertyof the system is that the step from object recognitionto pose estimation is completely automatic combiningboth appearance and geometric models. Rather thanconcentrating on the integration issues, our primary goalis to investigate the importance and effect of cameraconfiguration, their number and type, to the choice anddesign of the underlying visual algorithms. Experimentalevaluation is performed in a realistic indoor environmentwith occlusions, clutter, changing lighting and backgroundconditions.
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| 14. |
- Kragic, Danica, et al.
(författare)
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Model Based Techniques for Robotic Servoing and Grasping
- 2002
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Konferensbidrag (refereegranskat)abstract
- A robotic manipulation of objects typically involves object detection/recognition, servoing to the object, alignment and grasping. To perform fine alignment and finally grasping, it is usually necessary to estimate position and orientation (pose) of the object. In this paper we present a model based tracking system used to estimate and continuously update the pose of the object to be manipulated. Here, a wire-frame model is used to find and track features in the consequent images. One of the important parts of the system is the ability to automatically initiate the tracking process. The strength of the system is the ability to operate in an domestic environment (living room) with changing lighting and background conditions.
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| 15. |
- Kragic, Danica, et al.
(författare)
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Survey on Visual Servoing for Manipulation
- 2002
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Konferensbidrag (refereegranskat)abstract
- Vision guided robotics has been one of the major research issue for more than three decades. The more recent technological development facilitated the advancement in the area which has resulted in a number of successful and even commercial systems using off–the–shelf hardware. The applications of visually guided systems are many: from intelligent homes to automotive industry. However, one of the open and commonly stated problems in the area is the need for exchange of experiences and research ideas. In our opinion, a good starting point for this is to advertise the successes and propose a common terminology in form of a survey paper. The paper concentrates on different types of visual servoing: image based, position based and 2 1/2D visual servoing. Different issues concerning both the hardware and software requirements are considered and the most prominent contributions are reviewed. The proposed terminology is used to introduce a young researcher and lead the experts in the field through a three decades long historical field of vision guided robotics. We also include a number of real–world examples from our own research providing not only a conceptual framework but also illustrating most of the issues covered in the paper.
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| 16. |
- Kragic, Danica, et al.
(författare)
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Tracking Techniques for Visual Servoing Tasks
- 2000
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Konferensbidrag (refereegranskat)abstract
- Many of today's visual servoing systems rely on the use of markers on the object to provide features for control. There is thus a need for a visual system that provides control features regardless of the appearance of the object. Region based tracking is a natural approach since it does not require any special type of features. In this paper we present two different approaches to region based tracking: 1) a multi-resolution gradient based approach (using optical flow); and 2) a discrete feature based search approach. We present experiments conducted with both techniques for different types of image motions. Finally, the performance, drawbacks and limitations of used techniques are discussed
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| 17. |
- Kragic, Danica, et al.
(författare)
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Vision and tactile sensing for real world tasks
- 2003
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Konferensbidrag (refereegranskat)abstract
- Robotic fetch-and-carry tasks are commonly facilitated to demonstrate a number of research directions such as navigation, mobile manipulation, systems integration, etc. As a part of an integrated system in terms of a service robot framework, this paper describes a set of methods for real-world object manipulation tasks. We concentrate here on two particular parts of a manipulation sequence: i) robust visual servoing, and ii) grasping strategies. In terms of visual servoing we discuss the handling of singularities during a manipulation sequence. For grasping, we present a biologically motivated strategy using tactile feedback.
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| 18. |
- Kragic, Danica, et al.
(författare)
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Weak Models and Cue Integration for Real-Time Tracking
- 2002
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Konferensbidrag (refereegranskat)abstract
- Traditionally, fusion of visual information for tracking has been based on explicit models for uncertainty and integration. Most of the approaches use some form of Bayesian statistics where strong models are employed. We argue that for cases where a large number of visual features are available, weak models for integration may be employed. We analyze integration by voting where two methods are proposed and evaluated: i) response and ii) action fusion. The methods differ in the choice of Voting space: the former integrates visual information in image space and latter in velocity space. We also evaluate four weighting techniques for integration.
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| 19. |
- Kyrki, Ville, et al.
(författare)
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Measurement errors in visual servoing
- 2004
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Ingår i: 2004 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1- 5, PROCEEDINGS. - 0780382323 ; , s. 1861-1867
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Konferensbidrag (refereegranskat)abstract
- In recent years, a number of hybrid visual servoing control algorithms have been proposed and evaluated. For some time now, it has been clear that classical control approaches - image and position based - have some inherent problems. Hybrid approaches try to combine them to overcome these problems. However, most of the proposed approaches concentrate on the design of the control law, neglecting the issue of errors resulting from the sensory system. This paper addresses the issue of measurement errors in visual servoing. The particular contribution is the analysis of the propagation of image error through pose estimation and visual servoing control law. We have chosen to investigate the properties of the vision system and their effect to the performance of the control system. Two approaches are evaluated: i) position, and ii) 2 1/2 D visual servoing. We believe that our evaluation offers a tool to build and analyze hybrid control systems based on, for example, switching [1] or partitioning [2].
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| 20. |
- Kyrki, V., et al.
(författare)
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New shortest-path approaches to visual servoing
- 2004
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Konferensbidrag (refereegranskat)abstract
- In recent years, a number of visual servo control algorithms have been proposed. Most approaches try to solve the inherent problems of image-based and position-based servoing by partitioning the control between image and Cartesian spaces. However, partitioning of the control often causes the Cartesian path to become more complex, which might result in operation close to the joint limits. A solution to avoid the joint limits is to use a shortest-path approach, which avoids the limits in most cases. In this paper, two new shortest-path approaches to visual servoing are presented. First, a position-based approach is proposed that guarantees both shortest Cartesian trajectory and object visibility. Then, a variant is presented, which avoids the use of a 3D model of the target object by using homography based partial pose estimation.
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| 21. |
- Li, W., et al.
(författare)
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An architecture for indoor navigation
- 2004
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Ingår i: Proceedings - IEEE International Conference on Robotics and Automation. ; , s. 1783-1788
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Konferensbidrag (refereegranskat)abstract
- This paper is concerned with the design and implementation of a control architecture for a mobile robot that is to navigate in dynamic unknown indoor environments. It is based on the framework of Open Robot Control Software @ KTH, which is discussed and evaluated in this paper. As a hybrid architecture, it is decomposed into several basic components which can be classified as either deliberative or reactive. Each component can concurrently execute and communicate with another using unified communication interfaces. Scalability and portability and reusability are the goals of the design.
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| 22. |
- Lundberg, Carl, et al.
(författare)
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PDA interface for a field robot
- 2003
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Ingår i: Proc. of the IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS03). - 0780378601 ; , s. 2882-2888
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Konferensbidrag (refereegranskat)abstract
- Operating robots in an outdoor setting poses interesting problems in terms of interaction. To interact with the robot there is a need for a flexible computer interface. In this paper a PDA-based (personal digital assistant, i.e. a handheld computer) approach to robot interaction is presented. The system is designed to allow non-expert users to utilise the robot for operation in an urban exploration setup. The basic design is outlined and a first set of experiments are reported.
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| 23. |
- Ramström, Ola, et al.
(författare)
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Object detection using background context
- 2004
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Ingår i: PROCEEDINGS OF THE 17TH INTERNATIONAL CONFERENCE ON PATTERN RECOGNITION, VOL 3. - 0769521282 ; , s. 45-48
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Konferensbidrag (refereegranskat)abstract
- Detection of objects is in general a computationally demanding,task. To simplify the problem it is of interest to utilize contextual information and perform a staggered recognition where context is recognized as a precursor to object detection. In this paper an approach to object detection, using context is presented. The presented methodology is evaluated in the context of a tabletop scenario.
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| 24. |
- Topp, Elin Anna, et al.
(författare)
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An interactive interface for service robots
- 2004
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Ingår i: 2004 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1- 5, PROCEEDINGS. - 0780382323 ; , s. 3469-3474
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Konferensbidrag (refereegranskat)abstract
- In this paper, we present an initial design of an interactive interface for a service robot based on multi sensor fusion. We show how the integration of speech, vision and laser range data can be performed using a high level of abstraction. Guided by a number of scenarios commonly used in a service robot framework, the experimental evaluation will show the benefit of sensory integration which allows the design of a robust and natural interaction system using a set of simple perceptual algorithms.
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| 25. |
- Wulf, O., et al.
(författare)
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2D mapping of cluttered indoor environments by means of 3D perception
- 2004
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Ingår i: Proceedings - IEEE International Conference on Robotics and Automation. - : IEEE. ; , s. 4204-4209
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Konferensbidrag (refereegranskat)abstract
- This paper presents a combination of a 3D laser sensor and a line-base SLAM algorithm which together produce 2D line maps of highly cluttered indoor environments. The key of the described method is the replacement of commonly used 2D laser range sensors by 3D perception. A straightforward algorithm extracts a virtual 2D scan that also contains partially occluded walls. These virtual scans are used as input for SLAM using line segments as features. The paper presents the used algorithms and experimental results that were made in a former industrial bakery. The focus lies on scenes that are known to be problematic for pure 2D systems. The results demonstrate that mapping indoor environments can be made robust with respect to both, poor odometry and clutter.
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