Simon Watson

An Underwater Robotic Network for Monitoring Nuclear Waste Storage Pools

Nuclear power provides a significant portion of our current energy demand and is likely to become more wide spread with growing world population. However, the radioactive waste generated in these power plants must be stored for around 60 years in underwater storage pools before permanent disposal. These underwater storage environments must be carefully monitored and controlled to avoid an environmental catastrophe. In this paper, we present an underwater mobile sensor network that is being developed to monitor these waste storage pools. This sensing system will also be used in very old storage pools to build maps of their internal structure which can then be used for waste removal and pool decommissioning. In this paper, we outline the unique challenges of our application scenario which include robot localization in cluttered underwater environments and the effect of location errors on environment mapping. We also list other industrial applications that can benefit from our underwater sensor network.

Propulsion systems for micro-Autonomous Underwater Vehicles (μAUVs)

The development of small-scale sensor platforms for the internal monitoring of aqueous processes creates a range of challenges in terms of the provision of mobility. De-coupled x-y plane and z-axis movement, the need for low power consumption and a minimum of 4 degrees of freedom means that the suitability of conventional propulsion systems needs to be investigated. This paper presents a brief summary and comparison of the available propulsion options. Propellers have been chosen as the best means of propulsion and a novel approach to modeling and selection of both motors and propellers is given. The thruster configuration and initial mechanical designs for a μAUV are also outlined.

The Mechatronic Design of a Micro-Autonomous Underwater Vehicle

Micro-autonomous underwater vehicles (μAUVs) can form the basis of mobile underwater sensor networks for monitoring sub-surface cluttered environments. There are numerous technical challenges involved in constructing such vehicles using off-the-shelf components. This paper presents progress to date in the design of such a system, the problems encountered and possible solutions.

The design and technical challenges of a micro-autonomous underwater vehicle (μAUV)

Micro-Autonomous Underwater Vehicles (μAUVs) can form the basis of mobile underwater sensor networks for monitoring sub-surface cluttered environments. There are numerous technical challenges involved in constructing such vehicles using off-the-shelf components. This paper presents progress to date in the design of such a system, the problems encountered and possible solutions.

A de-coupled vertical controller for micro-autonomous underwater vehicles (μAUVs)

Micro-Autonomous Underwater Vehicles (μAUVs) can be used as part of underwater sensor networks in to monitor industrial processes. The high manoeuvrability requirements dictate that traditional AUV designs are not suitable. A prototype μAUV has been developed with independent movement capabilities in the horizontal and vertical planes. This paper outlines the work conducted on the design of a vertical control system and analyses the difference between the simulation and real-world implementation.

Design considerations for Micro-Autonomous Underwater Vehicles (μAUVs)

Mobile Underwater Sensor Networks provide an attractive solution to the problem of obtaining measurements from within liquid-based industrial processes. Most underwater vehicles are aimed at oceanographic applications and are therefore too large to be used in comparatively small processes. This paper sets out the design considerations for the development of a Micro-Autonomous Underwater Vehicle (??AUV) for use in a process environment.

AVEXIS—Aqua Vehicle Explorer for In-Situ Sensing

The AVEXIS (aqua vehicle explorer for in-situ sensing) underwater vehicles have been developed to allow characterization and monitoring of hazardous underwater environments with limited access points. A number of forms of the vehicle are being developed to assist in the decommissioning of the Sellafield nuclear facilities in Cumbria, U.K. The vehicles have been designed to be low-cost and have been constructed using novel manufacturing methods, such as 3D printing, which allows them to be built quickly and adds a high level of flexibility to the design. An acoustic communications and positioning system has also been developed which can be integrated into the vehicle or used as a stand-alone system which can be retrofitted onto existing vehicles.

Depth control for micro-autonomous underwater vehicles (μAUVs): Simulation and experimentation

Swarms of micro-autonomous underwater vehicles (μAUVs) are an attractive solution to the problem of nuclear storage pond monitoring. Independent movement in the horizontal and vertical planes is necessary to maximize manoeuvrability. This paper presents a comparison of different control strategies for independent depth control using both simulations and real experimental results. PID, sliding mode and a simplification of sliding mode (called ‘bounded PD’) are simulated using a MATLAB/SIMULINK model and are then compared to experimental results obtained when the controllers were implemented on a prototype μAUV.

Perpetual Robot Swarm: Long-Term Autonomy of Mobile Robots Using On-the-fly Inductive Charging

Swarm robotics studies the intelligent collective behaviour emerging from long-term interactions of large number of simple robots. However, maintaining a large number of robots operational for long time periods requires significant battery capacity, which is an issue for small robots. Therefore, re-charging systems such as automated battery-swapping stations have been implemented. These systems require that the robots interrupt, albeit shortly, their activity, which influences the swarm behaviour. In this paper, a low-cost on-the-fly wireless charging system, composed of several charging cells, is proposed for use in swarm robotic research studies. To determine the system’s ability to support perpetual swarm operation, a probabilistic model that takes into account the swarm size, robot behaviour and charging area configuration, is outlined. Based on the model, a prototype system with 12 charging cells and a small mobile robot, Mona, was developed. A series of long-term experiments with different arenas and behavioural configurations indicated the model’s accuracy and demonstrated the system’s ability to support perpetual operation of multi-robotic system.

ROS Integration for Miniature Mobile Robots

In this paper, the feasibility of using the Robot Operating System (ROS) for controlling miniature size mobile robots was investigated. Open-source and low-cost robots employ limited processors, hence running ROS on such systems is very challenging. Therefore, we provide a compact, low-cost, and open-source module enabling miniature multi and swarm robotic systems of different sizes and types to be integrated with ROS. To investigate the feasibility of the proposed system, several experiments using a single robot and multi-robots were implemented and the results demonstrated the amenability of the system to be integrated in low-cost and open-source miniature size mobile robots.