This paper carries out ship identification and real-time prediction based on nonlinear innovation, which an developed by virtue of the nonlinear innovation for ship maneuverability using the full-scale data. For the existing EKF and least squares algorithms, the nonlinear innovation Extended Kalman Filter (EKF) identification algorithm has higher identification efficiency and better convergence. It can solve the problem of inaccurate maneuvering prediction of traditional identification algorithms, remedied for the limitations of existing methods. The identification and real-time prediction results contrast with the full-scale data, shows that the proposed ship prediction model has significant prediction accuracy, and the algorithm is certain reliability. This identification method can be used to establish ship maneuvering prediction model.
In this study, we analyze two methodologies that can gain insights the outcome of battles quantitatively. One is the Lanchester Model (LM), which is classified into three categories: linear, square, and mixed style. The other is the Probabilistic Scenario Model (PSM). We compare the theory of the two models and recommend representative types of battles for each model. The proposed theory is applied to gain insights the outcome of several exampled battles. First, LM is applied to analyze historical warfare, and to estimate the result of future probable battles between manned warships and unmanned surface/aerial vehicles (USV/UAV). Second, PSM is applied to estimate the outcomes of various battle scenarios between manned warships and unmanned surface vehicles (USVs) using probability theory. Through this study, it was confirmed that the two quantitative combat models, i.e., LM and PSM, can be used not only to gain insights the result of warfare, but also to develop future weapons systems.
One of the characteristics of complex systems is the inability to accurately predict performance. Performance can be in the form of cost, schedule, or technical capability. Small perturbations in the system can result in large changes in outcome; these unpredicted large changes in outcome are considered emergent behavior. Traditional management techniques based on average or median performance are usually not adequate for complex systems. One approach to measuring complexity considers the total number of interacting elements, the number of unique elements, the number of connections among these elements, and the nature of these connections; addressing one or more of these factors reduces complexity. Complicated systems are similar to complex systems, but differ in that they are predictable. Traditional management techniques are usually much more successful with complicated systems as compared to complex systems; therefore, actions to reduce complexity through conversion of a complex system to a complicated system are a key enabler to successful management. While the design of some commercial ships is complicated, the design of naval warships has historically been complex. This complexity is evident through the management challenges the US Navy has experienced in the design, construction, and operation of warships. Because design is a dominant factor in how ships are operated and maintained, reducing complexity of the design as well as the complexity of the design process itself offers an opportunity to improve the cost, schedule adherence, and technical capability of our warships. This paper explores the complexity of naval warship design, including its impact on operations and maintenance, and offers recommendations for instantiating warship design, maintenance, and operation processes with more complicated attributes and fewer complex attributes; in this way, traditional management practices are more likely to succeed.
According to Winston Churchill and others, the Landing Ship, Tank (LST) was the most important vessel built during WWII. Churchill himself came up with the concept for the LST during the early campaigns of the war, but it was the determined efforts of British and American naval engineers, working side by side, that brought Churchill's musings to life. The first LSTs were designed by Rowland Baker of the Royal Corps of Naval Constructors, but Britain lacked the industrial capacity to build these ships in the large numbers needed to re-take the European continent. Instead, they turned to the American Lend-Lease program to design and build them. At the US Navy's Bureau of Ships, John C. Niedermair required just a few hours to develop a novel design to meet the strict British requirements to transport heavy tanks across an ocean, and land them on shallow beachheads. When the United States entered the war in December 1941, the US Navy took over the LST program, and fast-tracked its design, testing and construction. Just over one year after Niedermair's original pencil sketch, the first LST was delivered to the fleet. In all, 1,051 LSTs were built for both the British and American navies. The LSTs proved critical to Allied amphibious operations around the world, including the island-hopping campaigns in the Pacific, and were key to the success of the Allied invasion of Europe at Normandy.
The present study considers the effects of trim (by the stern) and increased displacement on the maneuverability of a naval vessel. In particular, the study explores the effect of extreme trim (the limit of allowed trim in naval ship damaged stability criteria). This paper presents the results from captive and free-running tests conducted on an intact and simulated damaged naval combatant model.
Fouling of marine substances on metal surfaces of submarines adversely affect their hydrodynamics, propulsion efficiency, maintenance, and importantly their acoustic signature and sensor performance. Similarly, corrosion damage increases maintenance requirements for submarines and other naval assets, making it difficult to achieve their expected service life. This paper reports on the science and engineering that underpin the development of a new polymeric nanocomposite-based coating material with anti-fouling, anti-corrosion, anechoic and self-healing properties. The coating material has been specifically developed as an effective and sustainable solution for management of marine fouling and corrosion as well as mitigation of sensor degradation in submarines without compromising the acoustic (sonar) signature of the platform. The coating material consists of: (i) a polyurea based polymeric matrix, (ii) nanocomposite particles comprising halloysite nanotubes loaded with the corrosion inhibiting agent NaNO3, (iii) urea formaldehyde-based microcapsules containing self-healing agent linseed oil, and (iv) super hydrophobic lubricant layer involving a low vapor pressure ferro-fluid. Coated and uncoated steel samples were subjected to corrosion and biofouling in water harvested from the Pacific Ocean, Newcastle harbor. Samples were characterized by a suite of electrochemical, biological and acoustics methods. The coating material exhibited remarkably good anti-corrosion and anti-fouling properties without altering the acoustic signature of the steel substrate.
The HydroDynamics SeaPerch team developed their Remotely Operated Vehicle (ROV) to effectively complete the Mission and the Obstacle Courses in the 2024 Seaperch competition. The team overcame many challenges and difficulties on their journey to creating their unique ROV by using the Engineering Design Process (EDP). One such challenge was designing motor mounts for their ROV. The team secured their 3D printed mounts in a Chlorinated Polyvinyl Chloride (CPVC) connector and fastened the motors in the mounts' adjustable casing. This provided a more consistent placement than using the standard zip tie method. The team also designed and 3D printed attachable kort nozzles to the motor mounts, which improved the propellers' efficiency and the ROV's acceleration. The kort nozzles also served as streamliners for a more concentrated flow, while protecting the propellers from getting tangled in loose strings. To improve maneuverability and speed, the team used CPVC to create a compact ROV. This, however, brought along a downside - reduced stability; placing the thrust motors wider helped make the ROV more stable and maneuverable. In addition, the team made sharkinspired fins and a beaver-inspired tail to control the ROV's pitch and roll, making it even more stable and controllable. The team also wanted to neutralize the cord's buoyancy so it wouldn't drag on the bottom of the pool, causing the ROV to drive slower. They attached tiny pieces of foam at two-foot intervals, making the cord neutrally buoyant, thereby eliminating the cord's drag and thus increasing the ROV's speed. Unfortunately, the cord was getting in the way, making the ROV perform the Obstacle Course slower, so the team abandoned that idea. Afterward, the team reflected on their design and thought of ways to improve for next year. They concluded that the pool noodle they used for buoyancy was causing substantial drag; therefore, in the future, they could try using syringes with air instead. Also, they thought that using a Polyethylene terephthalate sleeve on the cord could be advantageous because it is a very low-friction material that could further reduce the drag. Overall, their ROV performed approximate to 41% faster than the standard Utility ROV (SeaPerch Build Manual, 2021, p. 52).
The SeaJelly project vision is to create an ecosystem of STEM education tools and resources based upon soft aquatic robots, a hands-on way to learn that engages students K-12. The SeaJelly robot has a biomimetic design, looking like a jellyfish and moving in a way that is amazingly similar to live animal. It is fully capable of underwater operations, yet simple to build. Funded in 2022 by the U.S. Navy's STEM education efforts, the SeaJelly program has moved past the proof- of-concept stage. Construction kits, lesson plans, and education tools have all been defined and are now being modified and enhanced based on real student experiences. The goal is to make these program components available to schools nationwide as an innovative implementation of hands-on STEM education.
The Office of the Under Secretary of Defense, Acquisition, Technology, and Logistics (AT&L) recently presented analyses of cost and schedule growth on Major Defense Acquisition Programs (MDAPs) over the last 20 years (2013, 2014). For naval ships, AT&L (2013) concluded that contract work content growth (not capability growth) dominates total cost growth statistically. In addition, costs-over-target are significant and reflect poor cost estimation or faulty framing assumptions. AT&L (2014) also concluded prices on fixed-price contracts are only "fixed" if the contractual work content remains fixed, but this is often not the case. We show that under-sizing the ship during concept design studies increases ship outfit density and adds complexities to the design. These early-stage design decisions on sizing the ship are a major contributor to unnecessary work content growth later in Detail Design and Construction (DD&C) that cannot be eliminated no matter how productive the shipbuilder. However, new ship design methods are being developed and integrated with legacy physics- based design and analysis tools into a Rapid Ship Design Environment (RSDE) that will enable a more rational process for initially sizing ships. We also identify the need for early-stage design measures of complexity and ship costing tools that are more sensitive to these measures, and propose solutions that will aid decision-makers in reducing DD&C work content by making cost-effective design decisions in early-stage naval ship design.
This report discusses the strategy of a SimLE SeaSentinel Team for RoboBoat 2024 and the design of our system. The system consists of an Autonomous Surface Vehicle (ASV) named ASV Rybitwa, a Ground Segment and a set of procedures that allow us to effectively operate it all. In our work, we try to follow systems engineering principles. For this reason our work during the last ten months consisted of following phases: mission definition and general strategy, requirements, concept, design, production and testing. We have come to a conclusion that the best course of action for our team would be to try to approach the same tasks as last year. In essence, we decided that ASV Rybitwa will be an improved version of ASV Perkoz as most of or main design features proved to work very effectively during RoboBoat 2023 competition. ASV Rybitwa will be a modular, easily transportable catamaran made mostly of fibreglass and 3D printed PET-G. The propulsion system consisting of four thrusters will provide us with omnidirectional movement capabilities. In addition, we will equip our ASV with a water cannon in order to approach Task 4. All modules within our boat will communicate with each other via an Ethernet network. With the help of our new partner AQ Wiring Systems STG, we also managed to develop a more professional electrical system. Computer vision will rely solely on OAK-D stereo cameras. As a basis of our software system architecture, we decided to utilize Robot Operating System 2 (ROS2). We will maintain communication with our ASV with the help of three different radio links. Apart from the boat, we also decided to improve our Ground Segment, which includes a brand new Operator Control Station and modified transport and handling equipment. In addition, we greatly increased the amount and frequency of conducted tests.
For the 2022 Maritime RobotX Challenge Embry-Riddle Aeronautical University (ERAU) made significant improvements to their fully autonomous research platform, Minion. To complete mission tasks, Minion uses sophisticated sensory and perception algorithms fusing data from a suite consisting of multi-beam LiDARs, multi- modal imagery sensors, and a high precision GPS/INS. This data feeds decision-making algorithms that include neural network visual detection, long-range LiDAR-based object detection, and dynamic path planning. These processes are all tied together using a unique tasking system designed to initiate tasks when perception queues are received and select a task order to maximum time usage. The research team has also developed an autonomous drone platform, for completing the tasks that require aerial reconnaissance. All of Minion's systems are rated and tested to survive operations in adverse weather conditions, including high temperature, high humidity, and heavy precipitation. Minion was thoroughly tested using simulations, recorded data, and dozens of hours of in-water testing. The result of this is an advanced platform that is robust, reliable, and readily upgradable.
This paper describes the further development and application of a Dynamic Architecture Flow Optimization (DAFO) for naval ship Mission, Power, and Energy System (MPES) design. Improvements include the integration of Energy Storage Systems (ESSs) into the DAFO model, models for considering power generation ramp rates, improved timestep to timestep reconfiguration stability, treatment of ESS charging as a capability with value in the DAFO timestep effectiveness function, and further definition and refinement of operational architecture (OA) with required capability interfaces. With these improvements ESS capacity, charging, and discharging capabilities are assessed to minimize vulnerability and maximize effectiveness. The performance of the ESS is evaluated over time with both charging and discharging in realistic operational situations (OPSITs). By considering vulnerability in damage scenarios, the optimum number and location of ESSs in the system architecture may be determined. To accomplish this, the system logical architecture presented in previous papers (Parsons et. al. 2023) is expanded to include ESS charging and discharging capabilities to support operational situation (OPSIT) discrete-event multi-timestep optimization. The DAFO interfaces with a warfighting model, ship operational model, and mission capability models to determine optimum MPES alignment and provide capabilities (combat system, propulsion, and ESS charging/discharging) over multiple time steps.
Simulation is a critical capability for development of autonomous vehicles in general and unmanned ocean surface vehicles in particular. Because of time and cost constraints, real-world experiments alone are insufficient to test functionality and evaluate performance for autonomous ocean vessels across the necessary extents of space, time and environmental conditions. As a complement to on- water testing, simulation enables a variety of development activities such as testing across a variety of synthetic environmental conditions, parallel evaluation of many long duration scenarios and execution of statistical sampling within a complex design space. For much of the robotics community the open source Gazebo robot simulator has emerged as the de facto standard for prototyping and testing robotic systems. While Gazebo offers strong support for terrestrial, aerial and space robotics applications, less support is available for marine applications involving vehicles at and below the water surface. This paper describes the Virtual RobotX (VRX) simulation, a general purpose open source development and testing tool, based on Gazebo, capable of replicating the dynamics, environmental influences, sensor data and common tasks associated with unmanned surface vessel autonomy. This article highlights the application of these new capabilities using the VRX challenge reference implementation, a simulation-based robot competition designed to complement the physical Maritime RobotX Challenge.
The use of autonomous surface vessels (ASV) has been increasing in recent years. One primary challenge faced by ASVs is perception of the surrounding environment including objects like boats, docks, bridges, and buoys or signs. A common method for detecting such objects is using computer vision and machine learning algorithms with camera imagery. While most imagers use standard dynamic range (SDR), high dynamic range (HDR) imaging is generally considered superior in the field of photography. HDR images normally have higher detail and contrast, which could benefit object detection networks. Contrarily, most pre-trained object detection models are trained on SDR image sets, so using HDR images for transfer learning may not provide any extra benefit. Little research has been conducted to investigate if there are benefits to the use of HDR imagery for maritime machine learning. This work aims to compare the use of SDR and HDR imagery for object detection training in the maritime surface domain. Care is taken during this investigation to remove several potential training biases, such as class imbalances and aspect ratio. The results show that HDR imagery does not provide any extra benefit for maritime object detection than SDR imagery. Both image networks were trained to approximately 90% precision. However, the SDR image networks resulted in 10% higher recall and mAP scores. A remaining bias that couldn't be removed is the image type used for pre-trained object detection models.
In this work we conduct a qualitative study to analyze, through the views and experiences of program managers and Project OVERMATCH subject experts, the current state of needs and requirements for unmanned systems (UxS) communications security, and the associated cybersecurity and accreditation processes for the Department of Defense and Department of the Navy. The goal of this study is to obtain information from those working with the actual processes to help assess and guide viable network resiliency development options. We performed a qualitative interview study of 30 participants, resulting in insight into the effectiveness of current processes and the types of channel security properties that are useful in the unmanned system space. These results can help guide decision makers on the types of cryptographic channel security protocols that should be sought after from industry designs.
Problem Statement As climate change and pollution continue to harm our oceans, it is humanity's responsibility to take action for the exploration, preservation, and further research of Earth's oceans. Submersible remotely operated vehicles (ROVs) are a key tool in both research and preservation. Methodology This paper outlines key aspects of the creation process of a versatile ROV, including design, construction, and testing, to prepare it for navigating underwater obstacle courses and completing designated tasks. The ROV is equipped to conduct research and explore various oceanic environments, including hydrothermal vents, by handling extreme temperatures, pressures, and toxic chemicals. Results The ROV demonstrated its ability to undertake both research and ocean preservation tasks for long periods. It effectively navigated through harsh underwater environments and provided accurate data measurements, crucial for estimating greenhouse gas emissions from deepsea hydrothermal vents. Conclusion ROVs participating in the Sea Perch challenge must have versatility enabling them to be applied in other environmental conservation efforts such as the removal trash and pollutants from the ocean. This paper outlines key aspects of the creation process, including design, construction, and testing, to prepare ROVs capable navigating through underwater obstacle courses with varying environments and completing designated tasks must be meticulously considered and mitigated. The is capable of conducting research and exploring all aspects of the oceans, including hydrothermal vents. Hydrothermal vents are critical targets of ocean exploration and research due to the immense and diverse sea life that persists ROVs are necessary to aid researchers in exploring the harsh environments surrounding hydrothermal vents, where extreme temperatures, pressures, and toxic and corrosive chemicals are expected. The paramount aspect of ROV design and construction is to build versatility allows the submersible to undertake both research and ocean preservation tasks for long periods of time. It also important to estimate the rate of greenhouse gasses emitted from deep-sea hydrothermal vents for atmospheric and ocean scientists to calibrate climate models. ROVs navigating this harsh underwater environment are critical for investigating the deep ocean spaces where humans cannot go.
According to the conceptual similarities between nature and transportation, the design of systems and vehicles that are inspired by nature and attempt to solve a problem are currently ongoing research topics. The examination of living organisms with biomimicry methodology is essential to the physical and philosophical imitation of nature. Thus, the barriers between natural and engineering sciences are torn down, and the basis for academic and industry references is constructed. Submarines are frequently employed for vital functions and utilize the energy stored in batteries, particularly when in a submerged state. At that time, the service range is defined by stored energy. The need for greater energy capacity to accommodate a longer range will result in an increased overall weight and, therefore, an increase in required propulsion power. Rather than engaging in such a dilemma, the available battery pack can be efficiently utilized by consuming less energy during the same operation. Enhancing the propulsion system or optimizing the body form to minimize resistance might enhance energy efficiency. The purpose is to determine a bio-inspired hull form exposed with less resistance than the DARPA SUBOFF. The body forms such predatory fishes as Barracuda, Dorado, Little Tunny, and Sailfish are compared to the bare SUBOFF.
AquaPack Robotics at NC State University is returning to ne the reliability of the existing system. Several systems are stable, but others have required significant additional work. The lessons learned from the competition at TransDec in 2023 led us to another overhaul of the software system in Rust. The motivation behind this change is that this language and framework would enforce better coding practices and greater ease of use for our custom software stack. The previous Java framework proved more challenging to use than anticipated, leading to bad coding practices that saw failures at TransDec. Further systems are now fully realized such that SeaWolf VIII can attempt most of the competition course. Fully integrated manipulation systems allow for attempting torpedo and bin tasks, while the improved acoustics system allows us to attempt to surface in the octagon. Overall,this system has proven to be a stable platform suitable for continuous iteration, enabling the development of more complex systems.
The current NIMITZ and FORD Class aircraft carriers efficiently accommodated and supported historically assigned air wings. However, it may not be correct to assume that just because it has historically been so it will continue to be so in the future. In fact, aircraft operating from USN carriers are now larger than in the past and are predicted to grow in the future. Following this trend, this report analyzed whether the current aircraft carrier can efficiently support the composition of the air wing expected about 2030. Considering variables such as the area required for stealth aircraft support equipment and the expected sizes of the next-generation aircraft, it is analyzed that the area occupied by the future air wing exceeds the limit of the optimum density that the current aircraft carrier can effectively support. To meet the optimum density limitation of current NIMIZ class carriers, there are ways to reduce the number of helicopters on board and compact or reduce stealth aircraft support equipment, or compact next-generation aircraft. If Navy cannot choose any of these, there is no other option than replacing all operational NIMITZ class with Ford class aircraft carriers.
