Systems and Methods for Automated Vessel Navigation Using Sea State Prediction

Systems and methods for sea state prediction and autonomous navigation in accordance with embodiments of the invention are disclosed. One embodiment of the invention includes a method of predicting a future sea state including generating a sequence of at least two 3D images of a sea surface using at least two image sensors, detecting peaks and troughs in the 3D images using a processor, identifying at least one wavefront in each 3D image based upon the detected peaks and troughs using the processor, characterizing at least one propagating wave based upon the propagation of wavefronts detected in the sequence of 3D images using the processor, and predicting a future sea state using at least one propagating wave characterizing the propagation of wavefronts in the sequence of 3D images using the processor. Another embodiment includes a method of autonomous vessel navigation based upon a predicted sea state and target location

Vision-based landing of a simulated unmanned aerial vehicle with fast reinforcement learning

Landing is one of the difficult challenges for an unmanned aerial vehicle (UAV). In this paper, we propose a vision-based landing approach for an autonomous UAV using reinforcement learning (RL). The autonomous UAV learns the landing skill from scratch by interacting with the environment. The reinforcement learning algorithm explored and extended in this study is Least-Squares Policy Iteration (LSPI) to gain a fast learning process and a smooth landing trajectory. The proposed approach has been tested with a simulated quadrocopter in an extended version of the USARSim Unified System for Automation and Robot Simulation) environment. Results showed that LSPI learned the landing skill very quickly, requiring less than 142 trials

Autonomous Sailboat Navigation

The purpose of this study was to investigate novel methods on an unmanned sailing boat, which enables it to sail fully autonomously, navigate safely, and perform long-term missions. The author used robotic sailing boat prototypes for field experiments as his main research method. Two robotic sailing boats have been developed especially for this purpose. A compact software model of a sailing boat's behaviour allowed for further evaluation of routing and obstacle avoidance methods in a computer simulation. The results of real-world experiments and computer simulations are validated against each other. It has been demonstrated that autonomous boat sailing is possible by the effective combination of appropriate new and novel techniques that will allow autonomous sailing boats to create appropriate routes, to react properly on obstacles and to carry out sailing manoeuvres by controlling rudder and sails. Novel methods for weather routing, collision avoidance, and autonomous manoeuvre execution have been proposed and successfully demonstrated. The combination of these techniques in a layered hybrid subsumption architecture make robotic sailing boats a promising tool for many applications, especially in ocean observation

Aquatic escape for micro-aerial vehicles

As our world is experiencing climate changes, we are in need of better monitoring technologies. Most of our planet is covered with water and robots will need to move in aquatic environments. A mobile robotic platform that possesses efficient locomotion and is capable of operating in diverse scenarios would give us an advantage in data collection that can validate climate models, emergency relief and experimental biological research. This field of application is the driving vector of this robotics research which aims to understand, produce and demonstrate solutions of aerial-aquatic autonomous vehicles. However, small robots face major challenges in operating both in water and in air, as well as transition between those fluids, mainly due to the difference of density of the media. This thesis presents the developments of new aquatic locomotion strategies at small scales that further enlarge the operational domain of conventional platforms. This comprises flight, shallow water locomotion and the transition in-between. Their operating principles, manufacturing methods and control methods are discussed and evaluated in detail. I present multiple unique aerial-aquatic robots with various water escape mechanisms, spanning over different scales. The five robotic platforms showcased share similarities that are compared. The take-off methods are analysed carefully and the underlying physics principles put into light. While all presented research fulfils a similar locomotion objective - i.e aerial and aquatic motion - their relevance depends on the environmental conditions and supposed mission. As such, the performance of each vehicle is discussed and characterised in real, relevant conditions. A novel water-reactive fuel thruster is developed for impulsive take-off, allowing consecutive and multiple jump-gliding from the water surface in rough conditions. At a smaller scale, the escape of a milligram robotic bee is achieved. In addition, a new robot class is demonstrated, that employs the same wings for flying as for passive surface sailing. This unique capability allows the flexibility of flight to be combined with long-duration surface missions, enabling autonomous prolonged aquatic monitoring.Open Acces

Contribution to the model and navigation control of an autonomous underwater vehicle

This thesis deals with the further development of an existing underwater vehicle for autonomous navigation. The vehicle was conceived to navigate over the sea surface and, at certain fixed points, to dive vertically in order to obtain a profile of a water column. The main objectives of the thesis are the improvement of the hardware and software of the vehicle in order to make it fully operational, and the design and implementation of control techniques for autonomous navigation. The problem of autonomous navigation is addressed first with the calculation of an hydrodynamic model in 3DoF. An extensive study about the selection of the coefficients is performed, using a linearized model. The calculation of the coefficients is done using two approaches: a geometric one and another one based on least squares techniques applied to experimental data obtained during sea trials. The least squares method gives satisfactory results and the simulations fits the experimental data. The resulting hydrodynamic model is completed with the physical constraints of the actuators of the vehicle. Solving the autonomous navigation problem requires the design of controllers for both the inner loop (dynamic) and the outer loop (kinematic). Several solutions based on type-1 TSK fuzzy control are presented for velocity control, yaw control, pure pursuit navigation, and path following. The fuzzy controller is used to manage different linear controllers designed for specific conditions. The hydrodynamic model plays an important role in the design of the controller for the inner loop. In addition, a gain scheduled controller is designed to validate a particular case of the fuzzy controller in the inner loop. Regarding the finishing of the vehicle to be fully operational, the improvements begin with a new driver for the lateral thrusters because they lacked backwards movement capability. Additionally, upgrades in the handling of the vehicle had to devised. In this respect, a wireless on/off system is presented to power the vehicle, and a WiFi connection is adapted to manipulate the software of the vehicle remotely. Furthermore, a study of the currents and power of the immersion system in order to reduce the power consumption is performed, and the hardware is improved with the inclusion of some commercial devices, like an IMU, CTD, and acoustic localization system. The software is improved in several aspects. First, some problems derived from previous works are debugged. The system is then restructured with a multithread development, which provides robustness and modularity. As the system needed an extension of the protocol communication for easy handling, a robust protocol communication is implemented with the possibility to execute scripts. Finally, the existing graphical user interface is simplified in order to provide only the information required by the operator. In order to improve the buoyancy of the vehicle, several foams are designed, adjusted to the geometry of the vehicle, and a ballast system is also included for fine adjustment. Finally, several tests in the laboratory, a swimming pool, a channel, and at sea are performed in order to check the performance of the vehicle. Results show a correct behavior of hardware and software, and also validate the performance of the controllers designed for autonomous navigation.Esta tesis aborda el desarrollo de un vehículo submarino existente para la navegación autónoma. El vehículo fue concebido para navegar sobre la superficie del mar siguiendo ciertos puntos preestablecidos, y hacer inmersiones verticales con el fin de obtener un perfil de una columna de agua. Los objetivos principales de la tesis son la mejora del hardware y el software del vehículo con el fin de que sea plenamente operativo, y el diseño e implementación de técnicas de control para la navegación autónoma. El problema de la navegación autónoma se aborda primero con el cálculo de un modelo hidrodinámico en 3 grados de libertad. Un extenso estudio sobre la selección de los coeficientes se realizó usando un modelo linealizado. El cálculo de los coeficientes se obtuvo utilizando dos enfoques: primero un enfoque geométrico, y luego un enfoque basado en técnicas de mínimos cuadrados aplicados a los datos experimentales obtenidos durante las pruebas de mar. El método de mínimos cuadrados da resultados satisfactorios y las simulaciones se ajustan a los datos experimentales. El modelo hidrodinámico resultante se completa con las limitaciones físicas de los actuadores del vehículo. Resolver el problema de navegación autónoma requiere el diseño de controladores tanto para el lazo interno (dinámico) como el lazo exterior (cinemático). En este sentido se presentan varias soluciones basadas en controladores difusos TSK tipo 1 para el control de velocidad, control de guiñada, navegación "pure pursuit", y "path following". El controlador difuso se utiliza para gestionar diferentes controladores lineales diseñados para condiciones específicas, y el modelo hidrodinámico juega un papel importante en el diseño del controlador del lazo interno. Además, se diseñó un controlador tipo "gain scheduling" para validar un caso particular del controlador difuso. En cuanto a poner el vehículo completamente operativo, las mejoras comienzan con un nuevo controlador para los propulsores laterales pues éstos carecían del movimiento en reversa. Adicionalmente se realizaron varias mejoras respecto a la fácil manipulación del vehículo. En este sentido se implementó un sistema inalámbrico para el encendido y apagado del vehículo, y se adaptó una conexión WiFi para poder manipular el software remotamente. Luego, se realizó estudio de las corrientes y voltajes implicados en el sistema de inmersión con el fin de reducir el consumo de energía, y finalmente el hardware se mejora con la inclusión de algunos dispositivos comerciales como un IMU, CTD, y sistema de localización acústica. El software se mejora en varios aspectos. En primer lugar, algunos de los problemas derivados de desarrollos anteriores se depuran. A continuación, el sistema se reestructura con un desarrollo multi-hilo que proporciona robustez y modularidad. Debido a que el sistema necesitaba la extensión del protocolo de comunicación para un fácil manejo, se implementó un protocolo de comunicación robusto con la posibilidad de ejecutar scripts. Por último, se simplifica la interfaz gráfica de usuario existente con el fin de proporcionar solamente la información necesaria para el operador. Con el fin de mejorar la flotabilidad del vehículo, se diseñan varias espumas ajustadas a la geometría del vehículo, y también se incluye un sistema de lastre para un ajuste fino. Por último, se hicieron varias pruebas en laboratorio, piscina, un canal, y en el mar con el fin de comprobar el rendimiento del vehículo. Los resultados muestran un comportamiento correcto de hardware y software, y también validan el funcionamiento de los controladores diseñados para la navegación autónoma

NASA Tech Briefs, August 2012

Topics covered include: Mars Science Laboratory Drill; Ultra-Compact Motor Controller; A Reversible Thermally Driven Pump for Use in a Sub-Kelvin Magnetic Refrigerator; Shape Memory Composite Hybrid Hinge; Binding Causes of Printed Wiring Assemblies with Card-Loks; Coring Sample Acquisition Tool; Joining and Assembly of Bulk Metallic Glass Composites Through Capacitive Discharge; 670-GHz Schottky Diode-Based Subharmonic Mixer with CPW Circuits and 70-GHz IF; Self-Nulling Lock-in Detection Electronics for Capacitance Probe Electrometer; Discontinuous Mode Power Supply; Optimal Dynamic Sub-Threshold Technique for Extreme Low Power Consumption for VLSI; Hardware for Accelerating N-Modular Redundant Systems for High-Reliability Computing; Blocking Filters with Enhanced Throughput for X-Ray Microcalorimetry; High-Thermal-Conductivity Fabrics; Imidazolium-Based Polymeric Materials as Alkaline Anion-Exchange Fuel Cell Membranes; Electrospun Nanofiber Coating of Fiber Materials: A Composite Toughening Approach; Experimental Modeling of Sterilization Effects for Atmospheric Entry Heating on Microorganisms; Saliva Preservative for Diagnostic Purposes; Hands-Free Transcranial Color Doppler Probe; Aerosol and Surface Parameter Retrievals for a Multi-Angle, Multiband Spectrometer LogScope; TraceContract; AIRS Maps from Space Processing Software; POSTMAN: Point of Sail Tacking for Maritime Autonomous Navigation; Space Operations Learning Center; OVERSMART Reporting Tool for Flow Computations Over Large Grid Systems; Large Eddy Simulation (LES) of Particle-Laden Temporal Mixing Layers; Projection of Stabilized Aerial Imagery Onto Digital Elevation Maps for Geo-Rectified and Jitter-Free Viewing; Iterative Transform Phase Diversity: An Image-Based Object and Wavefront Recovery; 3D Drop Size Distribution Extrapolation Algorithm Using a Single Disdrometer; Social Networking Adapted for Distributed Scientific Collaboration; General Methodology for Designing Spacecraft Trajectories; Hemispherical Field-of-View Above-Water Surface Imager for Submarines; and Quantum-Well Infrared Photodetector (QWIP) Focal Plane Assembly

Tacking reduces bow-diving of high-speed unmanned sea surface vehicles

Reinhart F, Steil JJ, Huntsberger TL, Stoica A. Tacking reduces bow-diving of high-speed unmanned sea surface vehicles. In: Int. Symp. Learning and Adaptive Behavior in Robotic Systems. 2010: 177-182

Infrastructure for large-scale tests in marine autonomy

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 141-147).This thesis focuses on the development of infrastructure for research with large-scale autonomous marine vehicle fleets and the design of sampling trajectories for compressive sensing (CS). The newly developed infrastructure includes a bare-bones acoustic modem and two types of low-cost and scalable vehicles. One vehicle is a holonomic raft designed for station-keeping and precise maneuvering, and the other is a streamlined kayak for traveling longer distances. The acoustic modem, like the vehicles, is inexpensive and scalable, providing the capability of a large-scale, low-cost underwater acoustic network. With these vehicles and modems we utilize compressive sensing, a recently developed framework for sampling sparse signals that offers dramatic reductions in the number of samples required for high fidelity reconstruction of a field. Our novel CS sampling techniques introduce engineering constraints including movement and measurement costs to better apply CS to sampling with mobile agents. The vehicles and modems, along with compressive sensing, strengthen the movement towards large scale autonomy in the ocean environment.by Robert Andrew Hummel.S.M

The Third Battle

Since the beginning of the twentieth century, submarines have been the weapon of choice for weaker naval powers that wish to contest a dominant power\u27s control of the seas or its ability to project power ashore from the sea. This is because submarines have been and are likely to remain the weapon system with the highest leverage in a battle for control of the ocean surface. Hence, antisubmarine warfare (ASW) will always re-main the most important element of the U.S. Navy\u27s core mission-sea control.https://digital-commons.usnwc.edu/usnwc-newport-papers/1017/thumbnail.jp

Assessing the suitability of ship design for human factors issues associated with evacuation and normal operations

Evaluating ship layout for human factors (HF) issues using simulation software such as maritimeEXODUS can be a long and complex process. The analysis requires the identification of relevant evaluation scenarios; encompassing evacuation and normal operations; the development of appropriate measures which can be used to gauge the performance of crew and vessel and finally; the interpretation of considerable simulation data. In this paper we present a systematic and transparent methodology for assessing the HF performance of ship design which is both discriminating and diagnostic. The methodology is demonstrated using two variants of a hypothetical naval ship