| 1. |
- Aydemir, Alper, et al.
(författare)
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Exploiting and modeling local 3D structure for predicting object locations
- 2012
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Ingår i: Intelligent Robots and Systems (IROS), 2012 IEEE/RSJ International Conference on. - : IEEE. - 9781467317375 ; , s. 3885-3892
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Konferensbidrag (refereegranskat)abstract
- In this paper, we argue that there is a strong correlation between local 3D structure and object placement in everyday scenes. We call this the 3D context of the object. In previous work, this is typically hand-coded and limited to flat horizontal surfaces. In contrast, we propose to use a more general model for 3D context and learn the relationship between 3D context and different object classes. This way, we can capture more complex 3D contexts without implementing specialized routines. We present extensive experiments with both qualitative and quantitative evaluations of our method for different object classes. We show that our method can be used in conjunction with an object detection algorithm to reduce the rate of false positives. Our results support that the 3D structure surrounding objects in everyday scenes is a strong indicator of their placement and that it can give significant improvements in the performance of, for example, an object detection system. For evaluation, we have collected a large dataset of Microsoft Kinect frames from five different locations, which we also make publicly available.
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| 2. |
- Aydemir, Alper, et al.
(författare)
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What can we learn from 38,000 rooms? : Reasoning about unexplored space in indoor environments
- 2012
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Ingår i: Intelligent Robots and Systems (IROS), 2012 IEEE/RSJ International Conference on. - : IEEE. - 9781467317375 ; , s. 4675-4682
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Konferensbidrag (refereegranskat)abstract
- Many robotics tasks require the robot to predict what lies in the unexplored part of the environment. Although much work focuses on building autonomous robots that operate indoors, indoor environments are neither well understood nor analyzed enough in the literature. In this paper, we propose and compare two methods for predicting both the topology and the categories of rooms given a partial map. The methods are motivated by the analysis of two large annotated floor plan data sets corresponding to the buildings of the MIT and KTH campuses. In particular, utilizing graph theory, we discover that local complexity remains unchanged for growing global complexity in real-world indoor environments, a property which we exploit. In total, we analyze 197 buildings, 940 floors and over 38,000 real-world rooms. Such a large set of indoor places has not been investigated before in the previous work. We provide extensive experimental results and show the degree of transferability of spatial knowledge between two geographically distinct locations. We also contribute the KTH data set and the software tools to with it.
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| 3. |
- Karayiannidis, Yiannis, 1980-, et al.
(författare)
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"Open Sesame!" Adaptive Force/Velocity Control for Opening Unknown Doors
- 2012
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Ingår i: Intelligent Robots and Systems (IROS), 2012 IEEE/RSJ International Conference on. - : IEEE. - 9781467317375 ; , s. 4040-4047
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Konferensbidrag (refereegranskat)abstract
- The problem of door opening is fundamental for robots operating in domestic environments. Since these environments are generally less structured than industrial environments, several types of uncertainties associated with the dynamics and kinematics of a door must be dealt with to achieve successful opening. This paper proposes a method that can open doors without prior knowledge of the door kinematics. The proposed method can be implemented on a velocity-controlled manipulator with force sensing capabilities at the end-effector. The method consists of a velocity controller which uses force measurements and estimates of the radial direction based on adaptive estimates of the position of the door hinge. The control action is decomposed into an estimated radial and tangential direction following the concept of hybrid force/motion control. A force controller acting within the velocity controller regulates the radial force to a desired small value while the velocity controller ensures that the end effector of the robot moves with a desired tangential velocity leading to task completion. This paper also provides a proof that the adaptive estimates of the radial direction converge to the actual radial vector. The performance of the control scheme is demonstrated in both simulation and on a real robot.
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| 4. |
- Karumanchi, Sisir, et al.
(författare)
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Reactive control in environments with hard and soft hazards
- 2012
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Ingår i: Intelligent Robots and Systems (IROS), 2012 IEEE/RSJ International Conference on. - Piscataway, N.J. : IEEE Press. - 9781467317375 ; , s. 2863-2868
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Konferensbidrag (refereegranskat)abstract
- In this paper we present a generalization of reactive obstacle avoidance algorithms for mobile robots operating among soft hazards such as off-road slopes and deformable terrain. A new hazard avoidance scheme generalizes constraint based reactive algorithms [1], [2] from hard to soft hazards. Reactive controllers operate by directly parameterizing the closedloop dynamics of the system with respect to the environment the robot is operating in. Traditionally, reactive controllers are parameterized by weighting virtual attraction and repulsion forces from goals and obstacles [3], [4]. One pitfall of such parameterizations is sensitivity of the tuning parameters to the operating environment. A reactive controller tuned in one set of conditions is not applicable in another (e.g. a different density of obstacles). The algorithm presented in this paper has two key properties which are significant i) Parameterization is environment independent. ii) It can deal with non-binary environments that contain soft hazards. © 2012 IEEE.
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| 5. |
- Kim, Yong-Jae, et al.
(författare)
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Design of a tubular snake-like manipulator with stiffening capability by layer jamming
- 2012
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Ingår i: Intelligent Robots and Systems (IROS), 2012 IEEE/RSJ International Conference on. - Piscataway, N.J. : IEEE Press. - 9781467317375 ; , s. 4251-4256
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Konferensbidrag (refereegranskat)abstract
- This paper introduces a new mechanism for achieving tunable stiffness, named layer jamming, and presents a hollow snake-like manipulator having tunable stiffness capability. The layer jamming mechanism is composed of multiple layers of thin Mylar film, and makes use of amplified friction between the films by applying vacuum pressure. In contrast to other tunable stiffness technology, such as particle jamming or field-activated materials (MR or ER fluids), layer jamming occupies a small volume and thus can be applied to small, light weight manipulators. The snake-like manipulator presented here is composed only of Mylar film and wires, and has highly flexible and under-actuated properties without application of a vacuum; however, it becomes highly stiff when a vacuum is applied. In this paper the characteristics of layer jamming are explored: its stiffness and breaking strength are obtained both theoretically and experimentally, and a prototype manipulator is developed and experimentally characterized. © 2012 IEEE.
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| 6. |
- Madry, Marianna, 1982-, et al.
(författare)
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Improving Generalization for 3D Object Categorization with Global Structure Histograms
- 2012
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Ingår i: Intelligent Robots and Systems (IROS), 2012 IEEE/RSJ International Conference on. - : IEEE conference proceedings. - 9781467317375 ; , s. 1379-1386
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Konferensbidrag (refereegranskat)abstract
- We propose a new object descriptor for three dimensional data named the Global Structure Histogram (GSH). The GSH encodes the structure of a local feature response on a coarse global scale, providing a beneficial trade-off between generalization and discrimination. Encoding the structural characteristics of an object allows us to retain low local variations while keeping the benefit of global representativeness. In an extensive experimental evaluation, we applied the framework to category-based object classification in realistic scenarios. We show results obtained by combining the GSH with several different local shape representations, and we demonstrate significant improvements to other state-of-the-art global descriptors.
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| 7. |
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| 8. |
- Pecora, Federico, 1977-, et al.
(författare)
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On mission-dependent coordination of multiple vehicles under spatial and temporal constraints
- 2012
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Ingår i: IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781467317375 ; , s. 5262-5269
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Konferensbidrag (refereegranskat)abstract
- Coordinating multiple autonomous ground vehicles is paramount to many industrial applications. Vehicle trajectories must take into account temporal and spatial requirements, e : g :; usage of floor space and deadlines on task execution. In this paper we present an approach to obtain sets of alternative execution patterns (called trajectory envelopes) which satisfy these requirements and are conflict-free. The approach consists of multiple constraint solvers which progressively refine trajectory envelopes according to mission requirements. The approach leverages the notion of least commitment to obtain easily revisable trajectories for execution.
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| 9. |
- Qiu, Renxi, et al.
(författare)
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Towards Robust Personal Assistant Robots: Experience Gained in the SRS Project
- 2012
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Ingår i: IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2012. - : IEEE. - 9781467317375 ; , s. 1651-1657
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Konferensbidrag (refereegranskat)abstract
- SRS is a European research project for building robust personal assistant robots using ROS (Robotic Operating System) and Care-O-bot (COB) 3 as the initial demonstration platform. In this paper, experience gained while building the SRS system is presented. A main contribution of the paper is the SRS autonomous control framework. The framework is divided into two parts. First, it has an automatic task planner, which initialises actions on the symbolic level. The planner produces proactive robotic behaviours based on updated semantic knowledge. Second, it has an action executive for coordination actions at the level of sensing and actuation. The executive produces reactive behaviours in well-defined domains. The two parts are integrated by fuzzy logic based symbolic grounding. As a whole, they represent the framework for autonomous control. Based on the framework, several new components and user interfaces are integrated on top of COB's existing capabilities to enable robust fetch and carry in unstructured environments. The implementation strategy and results are discussed at the end of the paper.
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| 10. |
- Rudinac, M., et al.
(författare)
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Learning and recognition of objects inspired by early cognition
- 2012
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Ingår i: Intelligent Robots and Systems (IROS), 2012 IEEE/RSJ International Conference on. - : IEEE. - 9781467317375 ; , s. 4177-4184
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Konferensbidrag (refereegranskat)abstract
- In this paper, we present a unifying approach for learning and recognition of objects in unstructured environments through exploration. Taking inspiration from how young infants learn objects, we establish four principles for object learning. First, early object detection is based on an attention mechanism detecting salient parts in the scene. Second, motion of the object allows more accurate object localization. Next, acquiring multiple observations of the object through manipulation allows a more robust representation of the object. And last, object recognition benefits from a multi-modal representation. Using these principles, we developed a unifying method including visual attention, smooth pursuit of the object, and a multi-view and multi-modal object representation. Our results indicate the effectiveness of this approach and the improvement of the system when multiple observations are acquired from active object manipulation.
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| 11. |
- Saarinen, Jari, et al.
(författare)
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Independent Markov Chain Occupancy Grid Maps for Representation of Dynamic Environments
- 2012
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Ingår i: 2012 IEEE/RSJ International Conference on Intelligent Robots and Systems. - New York, USA : IEEE. - 9781467317368 - 9781467317375 - 9781467317351 ; , s. 3489-3495
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Konferensbidrag (refereegranskat)abstract
- In this paper we propose a new grid based approach to model a dynamic environment. Each grid cell is assumed to be an independent Markov chain (iMac) with two states. The state transition parameters are learned online and modeled as two Poisson processes. As a result, our representation not only encodes the expected occupancy of the cell, but also models the expected dynamics within the cell. The paper also presents a strategy based on recency weighting to learn the model parameters from observations that is able to deal with non-stationary cell dynamics. Moreover, an interpretation of the model parameters with discussion about the convergence rates of the cells is presented. The proposed model is experimentally validated using offline data recorded with a Laser Guided Vehicle (LGV) system running in production use.
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| 12. |
- Song, Meng, et al.
(författare)
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Natural feature based localization in forested environments
- 2012
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Ingår i: Intelligent Robots and Systems (IROS), 2012 IEEE/RSJ International Conference on. - Piscataway, N.J. : IEEE Press. - 9781467317375 ; , s. 3384-3390
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Konferensbidrag (refereegranskat)abstract
- This paper presents a new feature based scan matching method for solving 6D localization problem in forested environments. The proposed registration process includes two steps. First, the largest group of approximately parallel tree trunk features is utilized to align successive scans along the five dimensions except z direction. Tree correspondences are established by matching point patterns which are abstracted from the position relationships of trees. The optimal 5D transformation is thus determined based on the axes of two key tree pairs which are selected by evaluating their ability of tree alignment. Second, we assign the ground points of two scans into a grid of cells, and minimize z-direction difference of points in shared cells. The experimental results on data collected in real forested environments have demonstrated the effectiveness of this method. © 2012 IEEE.
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