Effect of Communication Delays on the Successful Coordination of a Group of Biomimetic AUVs

In this paper, the influence of delays on the ability of a formation control algorithm to coordinate a group of twelve Biomimetic Autonomous Underwater Vehicles (BAUVs) is investigated. In this study the formation control algorithm is a decentralized methodology based on the behavioural mechanisms of fish within school structures. Incorporated within this algorithm is a representation of the well-known and frequently used communication protocol, Time-Division-Multiple-Access (TDMA). TDMA operates by assigning each vehicle a specific timeslot during which it can broadcast to the remaining members of the group. The size of this timeslot varies depending on a number of operational parameters such as the size of the message being transmitted, the hardware used and the distance between neighbouring vehicles. Therefore, in this work, numerous timeslot sizes are tested that range from theoretical possible values through to values used in practice. The formation control algorithm and the TDMA protocol have been implemented within a validated mathematical of the RoboSalmon BAUV designed and manufactured at the University of Glasgow. The results demonstrate a significant deterioration in the ability of the formation control algorithms as the timeslot size is increased. This deterioration is due to the fact that as the timeslot size is increased, the interim period between successive communication updates increases and as a result, the error between where the formation control algorithm estimates each vehicle to be and where they actually are, increases. As a result, since the algorithm no longer has an accurate representation of the positioning of neighbouring vehicles, it is no longer capable of selecting the correct behavioural equation and subsequently, is unable to coordinate the vehicles to form a stable group structure

Renewable Energy Powered Autonomous Smart Ocean Surface Vehicles (REASOSE)

The REASOSE is not just an Ocean surface vehicle, its poly-type smart autonomous propulsion which eliminates the limitations of existing surface vehicles (remotely operated). The renewable energy source always proved to be abundance of availability in the environment, since the power created through renewable source with loss is engineering acceptance which can immobilise the vehicle. But REASOSE is a unique vehicle with poly-type propulsion incorporated with different renewable sources from the environment which furnishes the consistency of the vehicle inevitable. The REASOSE is a smart intelligent system of vehicle that autonomously switch over to the efficient propulsion as per the availability and in kind of any hindrances the vehicle acts smartly and reaches its destination contiguously. The proposed project novelty is not only stick to a line, the proposed vehicle serves to be change over for versatile applications, the vehicle will be incorporated with high definition live transmitted camera serves for coastal surveillance, deep sea monitoring and so on. The integrated CTD, ADCP and other oceanographic sensors can be a changeover in data collection at different area at required region and time. The stack-up space provides the transportation during unconditional or conditional mode of cargo transfer to required destination

Renewable Energy Powered Autonomous Smart Ocean Surface Vehicles (REASOSE)

The REASOSE is not just an Ocean surface vehicle, its poly-type smart autonomous propulsion which eliminates the limitations of existing surface vehicles (remotely operated). The renewable energy source always proved to be abundance of availability in the environment, since the power created through renewable source with loss is engineering acceptance which can immobilise the vehicle. But REASOSE is a unique vehicle with poly-type propulsion incorporated with different renewable sources from the environment which furnishes the consistency of the vehicle inevitable. The REASOSE is a smart intelligent system of vehicle that autonomously switch over to the efficient propulsion as per the availability and in kind of any hindrances the vehicle acts smartly and reaches its destination contiguously. The proposed project novelty is not only stick to a line, the proposed vehicle serves to be change over for versatile applications, the vehicle will be incorporated with high definition live transmitted camera serves for coastal surveillance, deep sea monitoring and so on. The integrated CTD, ADCP and other oceanographic sensors can be a changeover in data collection at different area at required region and time. The stack-up space provides the transportation during unconditional or conditional mode of cargo transfer to required destination

Intelligent Maneuvering of Underwater Vehicle

The main goal of this project is to design a controller in such a way that underwater vehicle (UWV) can maneuver automatically when it is subject to underwater disturbances. Nevertheless, short term target for this project is to ensure that the UWV is able to propagate in a straight line forward direction to designated location. This project focuses more on simulation results because the vehicle fails to operate and requires parts replacement. The first part of simulation utilizes the mathematical model. This part concludes that PID controller works the best with pitch control whereas PD controller works the best when coming to heading control. PID controller for pitch controller does not meet the standard performance; hence, it is re-tuned. After five trials, new set of parameters which display astounding results are obtained. Both controllers designed are able to respond to underwater disturbances effectively

Design and Evaluation of a Propulsion System for Small, Compact, Low-Speed Maneuvering Underwater Vehicles

Underwater vehicles used to perform precision inspection and non-destructive evaluation in tightly constrained or delicate underwater environments must be small, have low-speed maneuverability and a smooth streamlined outer shape with no appendages. In this thesis, the design and analysis of a new propulsion system for such underwater vehicles is presented. It consists primarily of a syringe and a plunger driven by a linear actuator and uses different inflow and outflow nozzles to provide continuous propulsive force. A prototype of the proposed propulsion mechanism is built and tested. The practical utility and potential efficacy of the system is demonstrated and assessed via direct thrust measurement experiments and by use of an initial proof-of-concept test vehicle. Experiments are performed to enable the evaluation and modelling of the thrust output of the mechanism as well as the speed capability of a vehicle employing the propulsion system

Hydrodynamic Modelling for a Transportation System of Two Unmanned Underwater Vehicles: Semi-Empirical, Numerical and Experimental Analyses

Underwater transportation is an essential approach for scientific exploration, maritime construction and military operations. Determining the hydrodynamic coefficients for a complex underwater transportation system comprising multiple vehicles is challenging. Here, the suitability of a quick and less costly semi-empirical approach to obtain the hydrodynamic coefficients for a complex transportation system comprising two Unmanned Underwater Vehicles (UUVs) is investigated, where the interaction effects between UUVs are assumed to be negligible. The drag results were verified by Computational Fluid Dynamics (CFD) analysis at the steady state. The semi-empirical results agree with CFD in heave and sway; however, they were overpredicted in surge due to ignoring the wake effects. Furthermore, experiments were performed for the validation of the time-domain motion simulations with semi-empirical and CFD results. The simulations which were performed with the CFD drags were close to the experiments. The semi-empirical approach could be relied on once a correction parameter is included to account for the interactive effect between multiple UUVs. Overall, this work makes a contribution by deriving a semi-empirical approach for the dynamic and controlling system of dual UUVs, with CFD and experiments applied to ascertain its accuracy and potential improvement