An adaptive autopilot design for an uninhabited surface vehicle

An adaptive autopilot design for an uninhabited surface vehicle Andy SK Annamalai The work described herein concerns the development of an innovative approach to the design of autopilot for uninhabited surface vehicles. In order to fulfil the requirements of autonomous missions, uninhabited surface vehicles must be able to operate with a minimum of external intervention. Existing strategies are limited by their dependence on a fixed model of the vessel. Thus, any change in plant dynamics has a non-trivial, deleterious effect on performance. This thesis presents an approach based on an adaptive model predictive control that is capable of retaining full functionality even in the face of sudden changes in dynamics. In the first part of this work recent developments in the field of uninhabited surface vehicles and trends in marine control are discussed. Historical developments and different strategies for model predictive control as applicable to surface vehicles are also explored. This thesis also presents innovative work done to improve the hardware on existing Springer uninhabited surface vehicle to serve as an effective test and research platform. Advanced controllers such as a model predictive controller are reliant on the accuracy of the model to accomplish the missions successfully. Hence, different techniques to obtain the model of Springer are investigated. Data obtained from experiments at Roadford Reservoir, United Kingdom are utilised to derive a generalised model of Springer by employing an innovative hybrid modelling technique that incorporates the different forward speeds and variable payload on-board the vehicle. Waypoint line of sight guidance provides the reference trajectory essential to complete missions successfully. The performances of traditional autopilots such as proportional integral and derivative controllers when applied to Springer are analysed. Autopilots based on modern controllers such as linear quadratic Gaussian and its innovative variants are integrated with the navigation and guidance systems on-board Springer. The modified linear quadratic Gaussian is obtained by combining various state estimators based on the Interval Kalman filter and the weighted Interval Kalman filter. Change in system dynamics is a challenge faced by uninhabited surface vehicles that result in erroneous autopilot behaviour. To overcome this challenge different adaptive algorithms are analysed and an innovative, adaptive autopilot based on model predictive control is designed. The acronym ‘aMPC’ is coined to refer to adaptive model predictive control that is obtained by combining the advances made to weighted least squares during this research and is used in conjunction with model predictive control. Successful experimentation is undertaken to validate the performance and autonomous mission capabilities of the adaptive autopilot despite change in system dynamics.EPSRC (Engineering and Physical Sciences Research Council

Incorporating multi-criteria optimization and uncertainty analysis in the model-based systems engineering of an autonomous surface craft

This thesis presents an effective methodology and tool set, that explicitly considers technological uncertainty, to enable design, development, and assessment of alternative system concept architectures for an autonomous unmanned surface vessel (USV) in a system of systems (SoS) context. Complex system designs often fail due to poor communication of customer needs and inadequate understanding of the overall problem. This frequently results in the design team missing the mark in transforming requirements into a successful conceptual design. Effective system design requires a defined, flexible, and structured context within which new technological ideas can be judged. Alternative physical architectures are then modeled, simulated, and compared to find the "best" solution for further examination. This thesis uses model-based systems engineering (MBSE) principles to develop a multi-criteria decision making (MCDM) model that allows designers to perform a solution neutral investigation of possible alternative physical architecture concepts. This ensures a consistent quantitative evaluation of warfighting capability, suitability, effectiveness, technology maturation, and risk before and during a program execution. This effort is in support of an extended program to design a system of unmanned systems intended to provide the DoD with a coordinated, multi-domain, multi-mission, autonomous security and warfighting asset.http://archive.org/details/incorporatingmul109454549Outstanding ThesisUS Navy (USN) author.Approved for public release; distribution is unlimited

Aerial Vehicles

This book contains 35 chapters written by experts in developing techniques for making aerial vehicles more intelligent, more reliable, more flexible in use, and safer in operation.It will also serve as an inspiration for further improvement of the design and application of aeral vehicles. The advanced techniques and research described here may also be applicable to other high-tech areas such as robotics, avionics, vetronics, and space

China Naval Modernization: Implications for U.S. Navy Capabilities - Background and Issues for Congress

This report focuses on the implications that certain elements of China’s military modernization may have for future required U.S. Navy capabilities. The issue for Congress addressed in this report is: How should China’s military modernization be factored into decisions about U.S. Navy programs? Congress’s decisions on this issue could significantly affect future U.S. Navy capabilities, U.S. Navy funding requirements, and the U.S. defense industrial base, including the shipbuilding industry

2020, UMaine News Press Releases

This is a catalog of press releases put out by the University of Maine Division of Marketing and Communications between January 2, 2020 and December 15, 2020