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60
Where’s waldo? sensor-based temporal logic motion planning
- in IEEE International Conference on Robotics and Automation, 2007
, 2007
"... Abstract — Given a robot model and a class of admissible environments, this paper provides a framework for automatically and verifiably composing controllers that satisfy high level task specifications expressed in suitable temporal logics. The desired task specifications can express complex robot b ..."
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Cited by 67 (9 self)
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Abstract — Given a robot model and a class of admissible environments, this paper provides a framework for automatically and verifiably composing controllers that satisfy high level task specifications expressed in suitable temporal logics. The desired task specifications can express complex robot behaviors such as search and rescue, coverage, and collision avoidance. In addition, our framework explicitly captures sensor specifications that depend on the environment with which the robot is interacting, resulting in a novel paradigm for sensor-based temporal logic motion planning. As one robot is part of the environment of another robot, our sensor-based framework very naturally captures multi-robot specifications. Our computational approach is based on first creating discrete controllers satisfying so-called General Reactivity(1) formulas. If feasible, the discrete controller is then used in order to guide the sensor-based composition of continuous controllers resulting in a hybrid controller satisfying the high level specification, but only if the environment is admissible. Index Terms — Motion planning, temporal logics, sensorbased planning, controller synthesis, hybrid control.
Towards Autonomous Topological Place Detection Using the Extended Voronoi Graph,”
- Proceeding of IEEE ICRA,
, 2005
"... Abstract-Autonomous place detection has long been a major hurdle to topological map-building techniques. Theoretical work on topological mapping has assumed that places can be reliably detected by a robot, resulting in deterministic actions. Whether or not deterministic place detection is always ac ..."
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Cited by 53 (9 self)
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Abstract-Autonomous place detection has long been a major hurdle to topological map-building techniques. Theoretical work on topological mapping has assumed that places can be reliably detected by a robot, resulting in deterministic actions. Whether or not deterministic place detection is always achievable is controversial; however, even topological mapping algorithms that assume non-determinism benefit from highly reliable place detection. Unfortunately, topological map-building implementations often have handcoded place detection algorithms that are brittle and domain dependent. This paper presents an algorithm for reliable autonomous place detection that is sensor and domain independent. A preliminary implementation of this algorithm for an indoor robot has demonstrated reliable place detection in real-world environments, with no a priori environmental knowledge. The implementation uses a local, scrolling 2D occupancy grid and a real-time calculated Voronoi graph to find the skeleton of the free space in the local surround. In order to utilize the place detection algorithm in non-corridor environments, we also introduce the extended Voronoi graph (EVG), which seamlessly transitions from a skeleton of a midline in corridors to a skeleton that follows walls in rooms larger than the local scrolling map.
Creating High-quality Paths for Motion Planning
- THE INTERNATIONAL JOURNAL OF ROBOTICS RESEARCH 2007; 26; 845
, 2007
"... Many algorithms have been proposed that create a path for a robot in an environment with obstacles. Most methods are aimed at finding a solution. However, for many applications, the path must be of a good quality as well. That is, a path should be short and should keep some amount of minimum clearan ..."
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Cited by 34 (2 self)
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Many algorithms have been proposed that create a path for a robot in an environment with obstacles. Most methods are aimed at finding a solution. However, for many applications, the path must be of a good quality as well. That is, a path should be short and should keep some amount of minimum clearance to the obstacles. Traveling along such a path reduces the chances of collisions due to the difficulty of measuring and controlling the precise position of the robot. This paper reports a new technique, called Partial shortcut, which decreases the path length. While current methods have difficulties in removing all redundant motions, the technique efficiently removes these motions by interpolating one degree of freedom at a time. Two algorithms are also studied that increase the clearance along paths. The first one is fast but can only deal with rigid, translating bodies. The second algorithm is slower but can handle a broader range of robots, including
Robot Homing by Exploiting Panoramic Vision
, 2005
"... We propose a novel, vision-based method for robot homing, the problem of computing a route so that a robot can return to its initial "home" position after the execution of an arbitrary "prior" path. The method assumes that the robot tracks visual features in panoramic views of th ..."
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Cited by 29 (2 self)
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We propose a novel, vision-based method for robot homing, the problem of computing a route so that a robot can return to its initial "home" position after the execution of an arbitrary "prior" path. The method assumes that the robot tracks visual features in panoramic views of the environment that it acquires as it moves. By exploiting only angular information regarding the tracked features, a local control strategy moves the robot between two positions, provided that there are at least three features that can be matched in the panoramas acquired at these positions. The strategy is successful when certain geometric constraints on the configuration of the two positions relative to the features are fulfilled. In order to achieve long-range homing, the features' trajectories are organized in a visual memory during the execution of the "prior" path. When homing is initiated, the robot selects Milestone Positions (MPs) on the "prior" path by exploiting information in its visual memory. The MP selection process aims at picking positions that guarantee the success of the local control strategy between two consecutive MPs. The sequential visit of successive MPs successfully guides the robot even if the visual context in the "home" position is radically different from the visual context at the position where homing was initiated. Experimental results from a prototype implementation of the method demonstrate that homing can be achieved with high accuracy, independent of the distance traveled by the robot. The contribution of this work is that it shows how a complex navigational task such as homing can be accomplished efficiently, robustly and in real-time by exploiting primitive visual cues. Such cues carry implicit information regarding the 3D structure of the environment. Thu...
Coordinated Multi-Robot Exploration using a Segmentation of the Environment
"... Abstract — This paper addresses the problem of exploring an unknown environment with a team of mobile robots. The key issue in coordinated multi-robot exploration is how to assign target locations to the individual robots such that the overall mission time is minimized. In this paper, we propose a n ..."
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Cited by 29 (2 self)
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Abstract — This paper addresses the problem of exploring an unknown environment with a team of mobile robots. The key issue in coordinated multi-robot exploration is how to assign target locations to the individual robots such that the overall mission time is minimized. In this paper, we propose a novel approach to distribute the robots over the environment that takes into account the structure of the environment. To achieve this, it partitions the space into segments, for example, corresponding to individual rooms. Instead of only considering frontiers between unknown and explored areas as target locations, we send the robots to the individual segments with the task to explore the corresponding area. Our approach has been implemented and tested in simulation as well as in real world experiments. The experiments demonstrate that the overall exploration time can be significantly reduced by considering our segmentation method. I.
A coverage algorithm for multi-robot boundary inspection
- In IEEE Int. Conf. on Robotics and Automation (ICRA
, 2005
"... Abstract—This paper introduces the multi-robot boundary coverage problem, wherein a group of k robots must inspect every point on the boundary of a 2-dimensional test environ-ment. Using a simplified sensor model, this inspection problem is converted to an equivalent graph representation. In this re ..."
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Cited by 18 (0 self)
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Abstract—This paper introduces the multi-robot boundary coverage problem, wherein a group of k robots must inspect every point on the boundary of a 2-dimensional test environ-ment. Using a simplified sensor model, this inspection problem is converted to an equivalent graph representation. In this representation, the coverage problem can be posed as the k-Rural Postman Problem (kRPP). We present a constructive heuristic which finds a solution to the kRPP, then use that solution to plan the robots ’ inspection routes. These routes provide complete coverage of the boundary and also balance the inspection load across the k robots. Simulations illustrate the algorithm’s performance and characteristics. Index Terms—Robot coverage, multiple robots, planning algorithms. I.
Path Planning for Mobile Robot Navigation using Voronoi Diagram and
- Fast Marching,” Int. Conference on Intelligent Robots and Systems
, 2006
"... Abstract—This paper presents a new sensor based global Path Planner which operates in two steps. In the first step the safest areas in the environment are extracted by means of a Voronoi diagram. In the second step Fast Marching Method is applied to the Voronoi extracted areas in order to obtain the ..."
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Cited by 17 (1 self)
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Abstract—This paper presents a new sensor based global Path Planner which operates in two steps. In the first step the safest areas in the environment are extracted by means of a Voronoi diagram. In the second step Fast Marching Method is applied to the Voronoi extracted areas in order to obtain the shortest path. In this way the trajectory obtained is the shortest between the safe possible ones. This two step method combines an extremely fast global planner operating on a simple sensor based environment modeling, while it operates at the sensor frequency. The main characteristics are speed and reliability, because the map dimensions are reduced to a unidimensional map and this map represents the safest areas in the environment for moving the robot. I.
Safety for Human-Robot Interaction
, 2005
"... This paper presents a hierarchical path planning and control strategy for ensuring safety during a human-robot interaction. At the planning stage, a two-step process is used where first the danger of the interaction is minimized, followed by a goal seeking optimization. This approach reduces the lik ..."
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Cited by 17 (3 self)
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This paper presents a hierarchical path planning and control strategy for ensuring safety during a human-robot interaction. At the planning stage, a two-step process is used where first the danger of the interaction is minimized, followed by a goal seeking optimization. This approach reduces the likelihood of encountering local minima due to conflicts between reducing danger and a demanded interaction task. At the control stage, the human intent signal is evaluated at every step to ensure safe operation of the robot. In initial simulation work, the controller drives the robot away from the planned interaction if danger is identified, and then allows the planned interaction to resume once the danger has passed. 1.
Enhancing corridor maps for real-time path planning in virtual environments
- COMPUTER ANIMATION AND SOCIAL AGENTS (CASA)
, 2008
"... A central problem in interactive virtual environments is planning high-quality paths for characters avoiding obstacles in the environment. Current applications require a path planner that is fast (to ensure real-time interaction with the environment) and flexible (to avoid local hazards). In additio ..."
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Cited by 14 (5 self)
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A central problem in interactive virtual environments is planning high-quality paths for characters avoiding obstacles in the environment. Current applications require a path planner that is fast (to ensure real-time interaction with the environment) and flexible (to avoid local hazards). In addition, paths need to be natural, i.e. smooth and short. To satisfy these requirements, we need an adequate representation of the free space stored in a convenient data structure, a fast mechanism for querying this data structure, and an algorithm that constructs natural paths for the characters. We improve an existing data structure, the Corridor Map, which represents the free space by a graph whose edges correspond to collision-free corridors. We show that this structure, together with a kd-tree, can be used for fast querying, resulting in a corridor that guides the global path of the character. Its local motions are controlled by force functions, providing the desired flexibility. Experiments show that the improvements lead to a method which can steer a crowd of ±10,000 characters in real-time.
