Author : Serdar Erkan
Publisher :
ISBN 13 :
Total Pages : 20 pages
Book Rating : 4.:/5 (261 download)
Book Synopsis Dynamic Fault Tolerant Mission Re-planning Algorithms for a Group of UUVs by : Serdar Erkan
Download or read book Dynamic Fault Tolerant Mission Re-planning Algorithms for a Group of UUVs written by Serdar Erkan and published by . This book was released on 2007 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: "As of their discovery, Unmanned Underwater Vehicles (UUVs) have been attracting the military's interest intensively. The number of projects that tries to incorporate UUVs in various military applications is increasing as the applicability of such clandestine, low-risk systems are being approved by simulations/real time experiments. In recent years, the system designs aiming to employ UUVs in groups are emerging to increase the efficiency of the mission critical applications like performing Intelligence, Surveillance and Reconnaissance (ISR) on operating areas, littoral penetration areas. Since these types of missions require high level of reliability, it is very important to take preventive cautions for a probable failure. In particular, during an ISR or survey mission, if one or more UUVs fail (potentially because of hardware failure, battery depletion, or any other unexpected reason), the assigned task of the failing UUV must be compensated by remaining active UUV(s). This paper proposes two approaches that provide solutions in case of a UUV failure during a distributed survey/ISR mission. Specifically, we assume an instance of ISR missions such that a group of UUVs is assigned to conduct patrolling on a predefined operational area of interest. Each vehicle is responsible to perform the mission continuously on a relatively small, dedicated portion of the operation area. As a requirement of our scenario, each UUV of the entire system must report its current condition to at least one other component. A component can be another UUV or the host station which can be a land base station, a host surface ship, a communication relay aircraft or a satellite. Hence, each vehicle must periodically send a hello message either to its nearest neighbor UUV via underwater transmission (if it can establish a connection) or to the host station via RF transmission by surfacing. Hello messages ensure that the sending UUV is in working condition and continue to perform its task. If any message can not be heard from a specific UUV after a certain threshold, it is concluded that UUV is down and it can not perform its assigned task anymore. (Joint Architecture for Unmanned Systems (JAUS) messaging standard is assumed to communicate among UUVs and host station(s).) Considering a high tension period or a real time war scenario, dead UUV's assigned patrolling area can have an operational importance. It can be an entrance/exit of an enemy naval base, an entrance/exit of friendly naval base (in a protective manner) or a passage which is geo-strategically important. Therefore, the remaining UUVs must be able to re-tasked in a sense that they must cover the dead UUV's patrolling area (in addition to their initially assigned areas) in a cooperative manner. Our proposed algorithm either divides the area among more than one remaining UUVs or assigns it to only one UUV considering the UUVs' potential energy consumptions and workloads. The explained mission replanning scenario is solved by two algorithms; a heuristic one and an ILP-based one. We did experiments on various scenarios using both algorithms and we compared and evaluated the algorithms to eachothers [sic]. Our experiments show that the results of the heuristic approach requires considerable amount of modification to be used in a real time application such as an Operator Control Unit (OCU) in modern unmanned systems. On the other hand IL-based approach takes significantly long time to return solutions which makes it also infeasible to be used in real time applications. Finally, considering these results, we pointed out our future works."
