Summary of Research 2000, Department of Mechanical Engineering

The views expressed in this report are those of the authors and do not reflect the official policy or position of the Department of Defense or U.S. Government.This report contains project summaries of the research projects in the Department of Mechanical Engineering. A list of recent publications is also included, which consists of conference presentations and publications, books, contributions to books, published journal papers, and technical reports. Thesis abstracts of students advised by faculty in the Department are also included

Navigation/traffic control satellite mission study. Volume 1 - Summary

System of satellites, ground stations, and hardware of various user craft for transoceanic traffic contro

Autonomous Surface Vehicle based docking for an Autonomous Underwater Vehicle

Autonomous underwater vehicles have been used as tools for underwater operations. Autonomy means the capability to perform deliberative planning on-board without any human interaction. The levels of autonomy of underwater vehicles have been increasing over the years. One essential enabler for autonomous operation concerns docking. Autonomous docking will allow vehicles to operate independently of human interaction in remote areas. Docking concepts range from underwater docking stations to launch and recovery from autonomous surface vessels.The Underwater Systems and Technologies Laboratory (LSTS) has been developing and using this type of vehicles for more than twenty years and therefore the need of automatic docking of vehicles has emerged. This dissertation aims to develop an approach for docking between two existing vehicles from the LSTS fleet. The vehicles would be an Autonomous Surface Vehicle (ASV) \textit{Caravela} and a Light Autonomous Underwater Vehicle (LAUV).For this reason, we study and discuss the derivation and simplification of motion equations for sub-aquatic and surface vehicles and known approaches for docking, between a fixed or a moving dock. We studied a way to have localization between the two vehicles using Global Positioning System (GPS) and/or Ultra-Short Baseline (USBL) and the internal Inertial Measurement Unit (IMU), currently available on the systems. Several state machines where implemented in order to have an optimized and fail-safe docking maneuver even having external disturbances like sea-currents on the docking approach.The whole approach was implemented using the tool-chain developed in LSTS (Dune, IMC and Neptus)

Navigation/traffic control satellite mission study. Volume 3 - System concepts

Satellite network for air traffic control, solar flare warning, and collision avoidanc

OPTIC FLOW BASED STATION-KEEPING AND WIND REJECTION FOR SMALL FLYING VEHICLES

Optic flow and Wide Field Integration (WFI) have shown potential for application to autonomous navigation of Unmanned Air Vehicles (UAVs). In this study the application of these same methods to other tasks, namely station-keeping and wind rejection, is examined. Theory surrounding optic flow, WFI and wind gust modeling is examined to provide a theoretical background. A controller based on a H∞ bounded formulation of the well known Linear Quadratic Regulator in designed to both mitigate wind disturbances and station-keep. The performance of this controller is assessed via simulation to determine both performance and trade-offs in implementation such as the method for optic flow calculation. Furthermore, flight tests are performed to examine the real world effectiveness of the controller. Finally, conclusions about potential improvement to implementation are drawn

UNMANNED UNDERWATER VEHICLE MISSION SYSTEMS ENGINEERING PRODUCT REUSE RETURN ON INVESTMENT

Unmanned Underwater Vehicles (UUVs) accomplish a wide spectrum of missions ranging from generic to extremely specific. Although not all UUVs can accomplish all missions, there is significant replication of the requirements and the systems across the family of UUVs. The design process for UUVs balances operational requirements, design feasibility, expected performance, schedule, budget, and ultimate system and life-cycle costs. The U.S. Department of Defense does not have an established process for developing UUV Systems Engineering (SE) requirements. This results in duplicative development efforts adding unnecessary costs to UUV programs. This paper investigates the SE requirements and interfaces across various UUV mission spaces to establish complexity and reuse weights. A Constructive SE Cost Model (COSYSMO) is applied to determine the cost advantage to reuse SE requirements for UUV assets across different mission spaces to determine an overall SE effort. Requirements from the baseline mission are then compared with requirements from eight other missions, and the efforts compared to determine a return on investment (ROI) for using previous missions as a baseline. Utilizing the resulting UUV requirement cost versus ROI can serve as a starting point for future UUV program concept design.Civilian, Department of the NavyCivilian, Department of the NavyCivilian, Department of the NavyCivilian, Department of the NavyCivilian, Department of the NavyApproved for public release. Distribution is unlimited

Service-oriented agent architecture for autonomous maritime vehicles

Advanced ocean systems are increasing their capabilities and the degree of autonomy more and more in order to perform more sophisticated maritime missions. Remotely operated vehicles are no longer cost-effective since they are limited by economic support costs, and the presence and skills of the human operator. Alternatively, autonomous surface and underwater vehicles have the potential to operate with greatly reduced overhead costs and level of operator intervention. This Thesis proposes an Intelligent Control Architecture (ICA) to enable multiple collaborating marine vehicles to autonomously carry out underwater intervention missions. The ICA is generic in nature but aimed at a case study where a marine surface craft and an underwater vehicle are required to work cooperatively. They are capable of cooperating autonomously towards the execution of complex activities since they have different but complementary capabilities. The architectural foundation to achieve the ICA lays on the flexibility of service-oriented computing and agent technology. An ontological database captures the operator skills, platform capabilities and, changes in the environment. The information captured, stored as knowledge, enables reasoning agents to plan missions based on the current situation. The ICA implementation is verified in simulation, and validated in trials by means of a team of autonomous marine robots. This Thesis also presents architectural details and evaluation scenarios of the ICA, results of simulations and trials from different maritime operations, and future research directions

Manned remote work station development article

The two prime objectives of the Manned Remote Work Station (MRWS) Development Article Study are to first, evaluate the MRWS flight article roles and associated design concepts for fundamental requirements and embody key technology developments into a simulation program; and to provide detail manufacturing drawings and schedules for a simulator development test article. An approach is outlined which establishes flight article requirements based on past studies of Solar Power Satellite, orbital construction support equipments, construction bases and near term shuttle operations. Simulation objectives are established for those technology issues that can best be addressed on a simulator. Concepts for full-scale and sub-scale simulators are then studied to establish an overall approach to studying MRWS requirements. Emphasis then shifts to design and specification of a full-scale development test article

Control and guidance systems for the navigation of a biomimetic autonomous underwater vehicle

The field of Autonomous Underwater Vehicles (AUVs) has increased dramatically in size and scope over the past three decades. Application areas for AUVs are numerous and varied, from deep sea exploration, to pipeline surveillance to mine clearing. The main concept behind this work was the design and the implementation of a control and guidance system for the navigation of a biomimetic AUV. In particular, the AUV analysed in this project tries to imitate the appearance and approximate the swimming method of an Atlantic Salmon and, for this reason, has been called RoboSalmo