Conference Papers
Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/28506
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Item Egress: An online path planning algorithm for boundary exploration(Institute of Electrical and Electronics Engineers Inc., 2012) Guruprasad, K.R.; Dasgupta, P.We consider the problem of navigating a mobile robot that is located at any arbitrary point within a bounded environment, to a point on the environment's outer boundary and then, using the robot to explore the perimeter of the boundary. The environment can have obstacles in it and the location and size of these obstacles are not provided a priori to the robot. We present an online path planning algorithm to solve this problem that requires very simple behaviors and computation on the robot. We analytically prove that by using our algorithm, the robot is guaranteed to reach and explore the outer boundary of the environment within a finite time. © 2012 IEEE.Item Multi-robot terrain coverage and task allocation for autonomous detection of landmines(SPIE, 2012) Dasgupta, P.; Muñoz-Meléndez, A.; Guruprasad, K.R.Multi-robot systems comprising of heterogeneous autonomous vehicles on land, air, water are being increasingly used to assist or replace humans in different hazardous missions. Two crucial aspects in such multi-robot systems are to: a) explore an initially unknown region of interest to discover tasks, and, b) allocate and share the discovered tasks between the robots in a coordinated manner using a multi-robot task allocation (MRTA) algorithm. In this paper, we describe results from our research on multi-robot terrain coverage and MRTA algorithms within an autonomous landmine detection scenario, done as part of the COMRADES project. Each robot is equipped with a different type of landmine detection sensor and different sensors, even of the same type, can have different degrees of accuracy. The landmine detection-related operations performed by each robot are abstracted as tasks and multiple robots are required to complete a single task. First, we describe a distributed and robust terrain coverage algorithm that employs Voronoi partitions to divide the area of interest among the robots and then uses a single-robot coverage algorithm to explore each partition for potential landmines. Then, we describe MRTA algorithms that use the location information of discovered potential landmines and employ either a greedy strategy, or, an opportunistic strategy to allocate tasks among the robots while attempting to minimize the time (energy) expended by the robots to perform the tasks. We report experimental results of our algorithms using accurately-simulated Corobot robots within the Webots simulator performing a multi-robot, landmine detection operation. © 2012 SPIE.Item A distributed algorithm for computation of exact Voronoi cell in a multi-robotic system(2012) Guruprasad, K.R.; Dasgupta, P.In this paper we propose an algorithm for distributed computation of Voronoi cell in a multi-robotic system. Each of the robots is assumed to know its own position and position of all other robots. The robots compute their Voronoi cells based only on this positional information, without any additional communication and cooperation with other robots. © 2012 IEEE.Item Distributed Voronoi partitioning for multi-robot systems with limited range sensors(2012) Guruprasad, K.R.; Dasgupta, P.We consider the problem of distributed partitioning of an environment by a set of robots so that each robot performs its operations in the region within the corresponding cell. Voronoi partitioning is one of the most attractive techniques that has been used to solve this problem. It has been used in several distributed multi-robotic system and sensor network applications, such as sensor coverage, search and rescue, and coverage path planning. For a truly distributed implementation of such problems, each robot should be able to compute the corresponding Voronoi cell in a distributed manner. Further, in a practical application, the robots' sensors may have limited range, thus each robot may operate within a portion of its Voronoi cell constrained by the sensor range. We describe a distributed algorithm for computation of this range constrained Voronoi cell where each robot independently constructs chords corresponding to other robots that are within a distance of twice its sensor circle radius. A robot then uses a simple and fast technique to remove inessential chords to calculate the vertices of its Voronoi cell. We prove completeness and correctness of the proposed algorithm, and also provide the upper and lower bounds on the computational complexity of our algorithm. The theoretical results are validated with the help of experiments to show that for different values of sensor ranges, our proposed algorithm incurs a time complexity that is significantly lower than that of the existing full Voronoi partition computation algorithm. The maximum number of steps required by our algorithm is also shown to be within a constant times the lower bound given by the number of neighbors of each node. © 2012 IEEE.Item Distributed, complete, multi-robot coverage of initially unknown environments using repartitioning(International Foundation for Autonomous Agents and Multiagent Systems (IFAAMAS) info@ifaamas.org, 2014) Hungerford, K.; Dasgupta, P.; Guruprasad, K.R.We consider the problem of coverage path planning by multiple robots in an environment where the location and geometry of obstacles are initially unknown to the robots. We propose a novel algorithm where the robots initially partition the environment using Voronoi partitioning. Each robot then uses an auction-based algorithm to reallocate inaccessible portions of its initial Voronoi cell to robots in neighboring Voronoi cells so that each robot is responsible for covering a set of contiguous connected regions. We have verified the performance of our algorithm on e-puck robots within the Webots simulator in different environments with different obstacle geometries and shown that it performs complete, non-overlapping coverage. © © 2014, International Foundation for Autonomous Agents and Multiagent Systems (www.ifaamas.org). All rights reserved.Item A repartitioning algorithm to guarantee complete, non-overlapping planar coverage with multiple robots(Springer Verlag service@springer.de, 2016) Hungerford, K.; Dasgupta, P.; Guruprasad, K.R.We consider the problem of coverage path planning in an initially unknown or partially known planar environment using multiple robots. Previously, Voronoi partitioning has been proposed as a suitable technique for coverage path planning where the free space in the environment is partitioned into non-overlapping regions called Voronoi cells based on the initial positions of the robots, and one robot is allocated to perform coverage in each region. However, a crucial problem arises if such a partitioning scheme is used in an environment where the location of obstacles is not known a priori—while performing coverage, a robot might perceive an obstacle that occludes its access to portions of its Voronoi cell and this obstacle might prevent the robot from completely covering its allocated region. This would either result in portions of the environment remaining uncovered or requires additional path planning by robots to cover the disconnected regions. To address this problem, we propose a novel algorithm that allows robots to coordinate the coverage of inaccessible portions of their Voronoi cell with robots in neighboring Voronoi cells so that they can repartition the initial Voronoi cells and cover a set of contiguous, connected regions. We have proved analytically that our proposed algorithm guarantees complete, non-overlapping coverage. We have also quantified the performance of our algorithm on e-puck robots within the Webots simulator in different environments with different obstacle geometries and shown that it successfully performs complete, non-overlapping coverage. © Springer Japan 2016.