Faculty Publications
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Publications by NITK Faculty
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Item Deploy and search strategy for multi-agent systems using Voronoi partitions(2007) Guruprasad, K.R.; Ghose, D.In this paper we analyze a deploy and search strategy for multi-agent systems. Mobile agents equipped with sensors carry out search operation in the search space. The lack of information about the search space is modeled as an uncertainty density distribution over the space, and is assumed to be known to the agents a priori. In each step, the agents deploy themselves in an optimal way so as to maximize per step reduction in the uncertainty density. We analyze the proposed strategy for convergence and spatial distributedness. The control law moving the agents has been analyzed for stability and convergence using LaSalle's invariance principle, and for spatial distributedness under a few realistic constraints on the control input such as constant speed, limit on maximum speed, and also sensor range limits. The simulation experiments show that the strategy successfully reduces the average uncertainty density below the required level. © 2007 IEEE.Item Multi-agent search using sensors with heterogeneous capabilities(International Foundation for Autonomous Agents and Multiagent Systems (IFAAMAS) info@ifaamas.org, 2008) Guruprasad, K.R.; Ghose, D.In this paper we introduce a new concept namely, generalized Voronoi partition and use it to formulate two heterogeneous multi-agent search strategies. The core idea is optimal deployment of agents having sensors with heterogeneous capabilities, in a search space so as to maximize search effectiveness. We address a few theoretical issues such as optimality of deployment, convergence and spatial distributedness of the control law and the search strategies. Copyright © 2008, International Foundation for Autonomous Agents and Multiagent Systems (www.ifaamas.org). All rights reserved.Item Multi-agent search strategy based on centroidal Voronoi configuration(2010) Guruprasad, K.R.; Ghose, D.We propose a combined deploy and search strategy for multi-agent systems using Voronoi partition. Agents such as mobile robots (AGVs, UAVs, or USVs) search the space to acquire knowledge about the space. Lack of information about the search space is modeled as an uncertainty density distribution, which is known a priori to all the agents at the beginning of search. It is shown that when the agents are located at the centroid of Voronoi cells, computed with the perceived uncertainty density, reduction in uncertainty density is maximized. While moving toward this optimal configuration, the agents simultaneously perform search acquiring the information about the search space, thereby reducing the uncertainty density. The proposed search strategy is guaranteed to reduce the average uncertainty density to any arbitrary level. Simulation experiments are carried out to validate the proposed search strategy and compare its performance with sequential deploy and search strategy proposed in the literature. The simulation results indicate that the proposed strategy performs better than sequential deploy and search in terms of faster search, and smoother and shorter robot trajectories. ©2010 IEEE.Item Communication Architecture for Autonomous Aerial Traffic Management(Institute of Electrical and Electronics Engineers Inc., 2022) Paul, S.; Jana, S.; Chopra, O.; Ratnoo, A.; Ghose, D.This paper presents a multi-agent communication paradigm for autonomous aerial traffic management. Multi-drone missions based on the existing ROS-based communication architecture heavily depend on the master node, and communication delay between nodes might not be sufficient for efficient inter-agent collision avoidance. In this paper, we have proposed a hybrid ROS-ROS2 communication architecture for centralised traffic management with the provision of distributed communication for collision avoidance and conflict resolution at intersections. The base station server responsible for traffic management runs on a ROS2 environment, ROS is used for communication with each onboard autopilot, and an intermediate add-on-module interfaces ROS and ROS2 messages. The content of the communication packets between the different nodes is decided based on the design requirements. Overall communication architecture is validated through simulation and hardware experiments. © 2022 IEEE.Item Automated multi-agent search using centroidal Voronoi configuration(2011) Guruprasad, K.R.; Ghose, D.This paper addresses the problem of automated multiagent search in an unknown environment. Autonomous agents equipped with sensors carry out a search operation in a search space, where the uncertainty, or lack of information about the environment, is known a priori as an uncertainty density distribution function. The agents are deployed in the search space to maximize single step search effectiveness. The centroidal Voronoi configuration, which achieves a locally optimal deployment, forms the basis for the proposed sequential deploy and search strategy. It is shown that with the proposed control law the agent trajectories converge in a globally asymptotic manner to the centroidal Voronoi configuration. Simulation experiments are provided to validate the strategy. © 2010 IEEE.Item Performance of a class of multi-robot deploy and search strategies based on centroidal voronoi configurations(2013) Guruprasad, K.R.; Ghose, D.This article considers a class of deploy and search strategies for multi-robot systems and evaluates their performance. The application framework used is deployment of a system of autonomous mobile robots equipped with required sensors in a search space to gather information. The lack of information about the search space is modelled as an uncertainty density distribution. The agents are deployed to maximise single-step search effectiveness. The centroidal Voronoi configuration, which achieves a locally optimal deployment, forms the basis for sequential deploy and search (SDS) and combined deploy and search (CDS) strategies. Completeness results are provided for both search strategies. The deployment strategy is analysed in the presence of constraints on robot speed and limit on sensor range for the convergence of trajectories with corresponding control laws responsible for the motion of robots. SDS and CDS strategies are compared with standard greedy and random search strategies on the basis of time taken to achieve reduction in the uncertainty density below a desired level. The simulation experiments reveal several important issues related to the dependence of the relative performances of the search strategies on parameters such as the number of robots, speed of robots and their sensor range limits. © 2013 Taylor & Francis Group, LLC.Item Heterogeneous locational optimisation using a generalised Voronoi partition(2013) Guruprasad, K.R.; Ghose, D.In this paper a generalisation of the Voronoi partition is used for locational optimisation of facilities having different service capabilities and limited range or reach. The facilities can be stationary, such as base stations in a cellular network, hospitals, schools, etc., or mobile units, such as multiple unmanned aerial vehicles, automated guided vehicles, etc., carrying sensors, or mobile units carrying relief personnel and materials. An objective function for optimal deployment of the facilities is formulated, and its critical points are determined. The locally optimal deployment is shown to be a generalised centroidal Voronoi configuration in which the facilities are located at the centroids of the corresponding generalised Voronoi cells. The problem is formulated for more general mobile facilities, and formal results on the stability, convergence and spatial distribution of the proposed control laws responsible for the motion of the agents carrying facilities, under some constraints on the agents speed and limit on the sensor range, are provided. The theoretical results are supported with illustrative simulation results. © 2013 Taylor & Francis Group, LLC.