The design and implementation of a multi-agent architecture to increase coordination efficiency in multi-AUV operations

This research addresses the problem of coordinating multiple autonomous underwater vehicle (AUV) operations. An intelligent mission executive has been created that uses multi-agent technology to control and coordinate multiple AUVs in communication deficient environments. By incorporating real time vehicle prediction, blackboardbased hierarchical mission plans and mission optimisation in conjunction with a simple broadcast communication system this system aims to handle the limitations inherent in underwater operations and intelligently control multiple vehicles. In this research efficiency is evaluated and then compared to the current state of the art in multiple AUV control. The research is then validated in real AUV coordination trials. Results will show that compared to the state of the art the control system developed and implemented in this research coordinates multiple vehicles more efficiently and is able to function in a range of poor communication environments. These findings are supported by in water validation trials with heterogeneous AUVs. This thesis will first present an in depth state of the art of the related research topics including multi-agent systems, collaborative robotics and autonomous underwater vehicles. The development and functionality of this research will then be explained followed by a detailed description of the experiments. Results are then presented both for the simulated and real world trials followed by a discussion of the findings

A Genetic Algorithms Approach to Learning Communication and Coordination in Simulated Robots

Abstract. This project is motivated by an existing robot system for mapping unknown environments and attempts to improve its effectiveness through the use of genetic algorithms. Using the Webots simulator, the mapping system is created using simulated Khepera robots and a simulated environment. The robots are controlled by a supervisor agent that makes the high-level decisions about tasks for individual robots to complete to accomplish the mapping effort. This research investigates the ability of adding a GA learning component to the supervisor to improve its ability to coordinate the robotic agents

Diethyl 2,3-dihydro­thieno[3,4-b]-1,4-dioxine-5,7-dicarboxyl­ate

The title compound, C12H14O6S, is a dicarboxylic acid diethyl ester of 3,4-ethyl­enedioxy­thio­phene, which is a component of electrically conductive poly(3,4-ethyl­enedioxy­thio­phene) (PEDOT). The ethyl­ene group is disordered over two sites with occupancy factors 0.64 and 0.36. Both the carbonyl groups are coplanar with the thio­phene ring. The mol­ecules form centrosymmetric dimers with an R 2 2(12) coupling by inter­molecular C—H⋯O hydrogen bonds [3.333 (5) Å] at the ethoxy­carbonyl groups. The dimer units are arranged to form a ribbon-like mol­ecular sheet

5,7-Di-2-pyridyl-2,3-dihydro­thieno[3,4-b][1,4]dioxine

The title compound, C16H12N2O2S, was prepared by a Neigishi cross-coupling reaction to investigate the coordination chemistry of thio­phene-containing ligands. In the mol­ecule, the pyridine rings are twisted from the thio­phene ring by 20.6 (1) and 4.1 (2)°. The six-membered dihydro­dioxine ring is in a half-chair conformation

Highly Sensitive Detection and Discrimination of Biogenic Amines Utilizing Arrays of Polyaniline/Carbon Black Composite Vapor Detectors

Chemically-sensitive resistors have been developed that allow rapid detection of an important class of compounds, biogenic amines, at levels of 1−10 parts per trillion in ambient air. The materials are composites of a conducting organic polymer, the emeraldine salt of polyaniline, with particles of another conducting phase, carbon black. The resistance response of an EM−DBSA(1:0.5)/CB (80:20) detector exposed to water (a), acetone (b), methanol (c), ethyl acetate (d), and butanol (e) is approximately a factor of a million smaller than that to butylamine (f)

Highly Sensitive Detection and Discrimination of Biogenic Amines Utilizing Arrays of Polyaniline/Carbon Black Composite Vapor Detectors

Chemically-sensitive resistors have been developed that allow rapid detection of an important class of compounds, biogenic amines, at levels of 1−10 parts per trillion in ambient air. The materials are composites of a conducting organic polymer, the emeraldine salt of polyaniline, with particles of another conducting phase, carbon black. The resistance response of an EM−DBSA(1:0.5)/CB (80:20) detector exposed to water (a), acetone (b), methanol (c), ethyl acetate (d), and butanol (e) is approximately a factor of a million smaller than that to butylamine (f)

Preparation and Properties of Vapor Detector Arrays Formed from Poly(3,4-ethylenedioxy)thiophene−Poly(styrene sulfonate)/Insulating Polymer Composites

Poly(3,4-ethylenedioxy)thiophene−poly(styrene sulfonate) (PEDOT−PSS) was used as the conductive component in a matrix of chemically different insulating polymers to form an array of vapor detectors. Such composites produced larger relative differential resistance responses when exposed to polar analytes than did the corresponding carbon black filled polymer composite detectors. However, the PEDOT−PSS composites produced smaller responses than carbon black composites when exposed to nonpolar analytes. The resolving power of a PEDOT−PSS detector array was compared to that of a carbon black composite array for a broadly construed set of organic vapors. The PEDOT−PSS array exhibited better, on average, discrimination between pairs of polar analytes and polar/nonpolar analytes than did the carbon black composite array. The carbon black composite array outperformed the PEDOT−PSS array in discriminating between nonpolar compounds. The addition of PEDOT−PSS composites to an array of carbon black composite detectors therefore can produce improved overall discrimination in a vapor sensor system when used in tasks to differentiate between of a broad set of analyte vapors

A water-gated organic thin film transistor as a sensor for water-borne amines

The p-type semiconducting polymer Poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene) (PBTTT) displays innate sensitivity to water-borne amines. We demonstrate this with the help of water- gated PBTTT thin film transistors (TFTs). When octylamine is added to the gating water, TFTs respond with a significantly reduced saturated drain current. Underlying TFT drift is minimised by initial conditioning, and remaining drift can be accounted for by normalising current response to the current level under purge immediately before exposure. Normalised current response vs. amine concentration is reproducible between different transistors, and can be modelled by a Langmuir surface adsorption isotherm, which suggests physisorption of analyte at the PBTTT surface, rather than bulk penetration. Same PBTTT transistors do not respond to 1- octanol, confirming the specific affinity between amines and thiophene- based organic semiconductors

Solvent Vapour Detection with Cholesteric Liquid Crystals—Optical and Mass-Sensitive Evaluation of the Sensor Mechanism†

Cholesteric liquid crystals (CLCs) are used as sensitive coatings for the detection of organic solvent vapours for both polar and non-polar substances. The incorporation of different analyte vapours in the CLC layers disturbs the pitch length which changes the optical properties, i.e., shifting the absorption band. The engulfing of CLCs around non-polar solvent vapours such as tetrahedrofuran (THF), chloroform and tetrachloroethylene is favoured in comparison to polar ones, i.e., methanol and ethanol. Increasing solvent vapour concentrations shift the absorbance maximum to smaller wavelengths, e.g., as observed for THF. Additionally, CLCs have been coated on acoustic devices such as the quartz crystal microbalance (QCM) to measure the frequency shift of analyte samples at similar concentration levels. The mass effect for tetrachloroethylene was about six times higher than chloroform. Thus, optical response can be correlated with intercalation in accordance to mass detection. The mechanical stability was gained by combining CLCs with imprinted polymers. Therefore, pre-concentration of solvent vapours was performed leading to an additional selectivity