Path Planning of an Autonomous Surface Vehicle based on Artificial Potential Fields in a Real Time Marine Environment

With growing advances in technology and the everyday dependence on oceans for resources, the role of unmanned marine vehicles has increased many a fold. Extensive operations having naval, civil and scientific applications are being undertaken and demands are being placed on them to increase their flexibility and adaptability. A key factor for such vehicles is the requirement for them to possess a path planning subsystem. Most path planning techniques are implemented in self-simulated environments. This study accounts for use of artificial potential field in path planning of an autonomous surface vehicle (ASV) in a real time marine environment. Path cost, path length and computational time are described to ensure the effectiveness of the motion planning

Towards use of Dijkstra Algorithm for Optimal Navigation of an Unmanned Surface Vehicle in a Real-Time Marine Environment with Results from Artificial Potential Field

The growing need of ocean surveying and exploration for scientific and industrial application has led to the requirement of routing strategies for ocean vehicles which are optimal in nature. Most of the optimal path planning for marine vehicles had been conducted offline in a self‐made environment. This paper takes into account a practical marine environment, i.e. Portsmouth Harbour, for finding an optimal path in terms of computational time between source and end points on a real time map for an USV. The current study makes use of a grid map generated from original and uses a Dijkstra algorithm to find the shortest path for a single USV. In order to benchmark the study, a path planning study using a well‐known local path planning method artificial path planning (APF) has been conducted in a real time marine environment and effectiveness is measured in terms of path length and computational time

Advanced Feature Extraction and Dimensionality Reduction for Unmanned Underwater Vehicle Fault Diagnosis

This paper presents a novel approach to the diagnosis of blade faults in an electric thruster motor of unmanned underwater vehicles (UUVs) under stationary operating conditions. The diagnostic approach is based on the use of discrete wavelet transforms (DWT) as a feature extraction tool and a dynamic neural network (DNN) for fault classification. The DNN classifies between healthy and faulty conditions of the trolling motor by analyzing the stator current and vibration signals. To overcome feature redundancy, which affects diagnosis reliability, the Orthogonal Fuzzy Neighbourhood Discriminant Analysis (OFNDA) approach is found to be the most effective. Four faulty conditions were analyzed under laboratory conditions, and the results obtained from experiment demonstrate the effectiveness and reliability of the proposed methodology in classifying the different faults faster and more accurately

Developing resources to facilitate culturally-sensitive service planning and delivery – doing research inclusively with people with learning disabilities

Background Black, Asian and minority ethnic people with learning disabilities face inequities in health and social care provision. Lower levels of service uptake and satisfaction with services have been reported, however, this is largely based on the views of carers. The ‘Access to Social Care: Learning Disabilities (ASC-LD)’ study sought to explore the views and experiences of social support services among adults with learning disabilities from Black, Asian and minority ethnic communities. Interviews with 32 Black, Asian and minority ethnic adults with learning disabilities were conducted to explore participants’ cultural identities, their understanding and experience of ‘support’. The views and experiences expressed in the ASC-LD study were used in the ‘Tools for Talking project’ to develop a suite of resources designed to facilitate culturally-sensitive communication and information-sharing, service planning and delivery through improved mutual understanding between providers and users of services. This paper describes the Tools for Talking project which sought to co-develop the resources through a partnership event. Methods An inclusive approach was adopted to address issues that are important to people with learning disabilities, to represent their views and experiences, and to involve Black, Asian and minority ethnic people with learning disabilities in the research process. Partnerships were developed with provider organisations and service users who were invited to a ‘Partnership Event’. Collaborators at the partnership event were asked to comment on and evaluate draft resources which included a series of videos and activities to explore topics that emerged as important in the ASC-LD study. Their comments were collated and the tools developed as they suggested. Results Using the results from the ASC-LD study helped to ensure that the draft resources were relevant to service users, addressing topics that were important to them. The partnership event was an effective method to collaborate with a relatively large number of stakeholders. However, the event was resource intensive and required substantial planning to ensure active and meaningful participation. Considerations, such as inviting stakeholders, developing the programme and selecting a venue are discussed. Conclusions The partnership approach has led to the development of a set of five illustrative videos and accompanying activities that address issues that emerged from the collaborative process including: culture, activities, support from staff, important people, choices and independence. These resources are freely available at: www.Toolsfortalking.co.uk. They are designed to be used by users and providers of services, but may also be useful in other settings

A review on biomass-derived materials and their applications as corrosion inhibitors, catalysts, food and drug delivery agents

Owing to the overconsumption of petroleum-based resources and growing demand for fossil-based fuels and chemicals, it has become imperative to adopt alternative resources that are renewable. With the availability of biomass, it is believed that this technology has the capability to valorize waste into wealth. Recently, efficient utilization of plant biomass, a chief renewable resource, has gained tremendous attention in research as it offers distinct social, economic, and sustainable benefits. The present review focuses on the various biomass from waste resources. Subsequently, the applications of these polymeric biomass composites are reviewed in catalysis, drug delivery, and food applications. Finally, corrosion studies along with DFT calculations and theoretical aspects have also been reviewed. Naturally occurring carbohydrate polymers found in lignocellulosic biomass are biopolymers have been used for various physical and chemical applications; as catalyst, coatings, drug delivery, corrosion inhibitors etc. This review reports these material applications of carbohydrate polymers. In this review, we focus on new and emerging applications of polymers from lignocellulosic biomass

Turbine Airfoil With CMC Leading-Edge Concept Tested Under Simulated Gas Turbine Conditions

Silicon-based ceramics have been proposed as component materials for gas turbine engine hot-sections. When the Navy s Harrier fighter experienced engine (Pegasus F402) failure because of leading-edge durability problems on the second-stage high-pressure turbine vane, the Office of Naval Research came to the NASA Glenn Research Center at Lewis Field for test support in evaluating a concept for eliminating the vane-edge degradation. The High Pressure Burner Rig (HPBR) was selected for testing since it could provide temperature, pressure, velocity, and combustion gas compositions that closely simulate the engine environment. The study focused on equipping the stationary metal airfoil (Pegasus F402) with a ceramic matrix composite (CMC) leading-edge insert and evaluating the feasibility and benefits of such a configuration. The test exposed the component, with and without the CMC insert, to the harsh engine environment in an unloaded condition, with cooling to provide temperature relief to the metal blade underneath. The insert was made using an AlliedSignal Composites, Inc., enhanced HiNicalon (Nippon Carbon Co. LTD., Yokohama, Japan) fiber-reinforced silicon carbide composite (SiC/SiC CMC) material fabricated via chemical vapor infiltration. This insert was 45-mils thick and occupied a recessed area in the leading edge and shroud of the vane. It was designed to be free floating with an end cap design. The HPBR tests provided a comparative evaluation of the temperature response and leading-edge durability and included cycling the airfoils between simulated idle, lift, and cruise flight conditions. In addition, the airfoils were aircooled, uniquely instrumented, and exposed to the exact set of internal and external conditions, which included gas temperatures in excess of 1370 C (2500 F). In addition to documenting the temperature response of the metal vane for comparison with the CMC, a demonstration of improved leading-edge durability was a primary goal. First, the metal vane was tested for a total of 150 cycles. Both the leading edge and trailing edge of the blade exhibited fatigue cracking and burn-through similar to the failures experienced in service by the F402 engine. Next, an airfoil, fitted with the ceramic leading edge insert, was exposed for 200 cycles. The temperature response of those HPBR cycles indicated a reduced internal metal temperature, by as much as 600 F at the midspan location for the same surface temperature (2100 F). After testing, the composite insert appeared intact, with no signs of failure on either the vane s leading or trailing edge. Only a slight oxide scale, as would be expected, was noted on the insert. Overall, the CMC insert performed similarly to a thick thermal barrier coating. With a small air gap between the metal and the SiC/SiC leading edge, heat transfer from the CMC to the metal alloy was low, effectively lowering the temperatures. The insert's performance has proven that an uncooled CMC can be engineered and designed to withstand the thermal up-shock experienced during the severe lift conditions in the Pegasus engine. The design of the leading-edge insert, which minimized thermal stresses in the SiC/SiC CMC, showed that the CMC/metal assembly can be engineered to be a functioning component

Optimal path planning of unmanned surface vehicles

The publisher has released this paper this under the Creative Commons CC BY-NC-ND licence. This release is used to provide the authority for open access deposit in Pearl, but please note that the licence forbids commercial use and the distribution of derivative works.Present study reviews the current methodologies adopted for optimal path planning of single unmanned surface vehicles and studies associated with swarm of unmanned surface vehicles. This also discusses the challenges and scopes, which can act as objectives, for future research towards path planning of such marine craft

USV Navigation in a Real-Time Map using Intelligent Path Planner

Oral presentation and print abstract only; no proceedings. Abstract appeared in Journal of Applied Mechanical EngineeringUnmanned surface vehicles (USV) are the recent trend in marine robotics due to their diverse application and easy deployment. Navigation of such USV in a real time marine environment is a major challenge and creates a need towards development of intelligent path planners which can increase the system autonomy. Many such intelligent path planning studies have been conducted in the area of mobile robotics but needs a lot more research to be conducted in area of marine robotics. In this study, a well know intelligent path planner A* has been implemented in a real time map using safety distance from obstacle as the criteria towards generating optimal trajectory for a single USV navigation. Different safety distances from obstacles ranging from 10 pixels to 40 pixels have been used to generate optimal trajectory and comparative performance has been analyzed in terms of computational time and path length. In this study, Portsmouth Harbour has been considered as area of study to determine the effectiveness of A* algorithm with different safety distance from obstacle as constraint. Algorithm has been validated on computer-based simulations using C++ and OpenCV libraries