Download or read book Using Discrete Event Simulation to Assess Obstacle Location Accuracy in the REMUS Unmanned Underwater Vehicle written by Timothy E. Allen and published by . This book was released on 2004-06-01 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt: Navy personnel use the REMUS unmanned underwater vehicle to search for submerged objects. Navigation inaccuracies lead to errors in predicting the location of objects and thus result in increased search times for Explosive Ordnance Disposal (EOD) teams searching for the object post-mission. This thesis explores contributions to navigation inaccuracy using Discrete Event Simulation (DES) to model the vehicle's navigation system and operational performance. The DES produced for this thesis uses the JAVA-based Simkit package to simulate the navigation system in REMUS. The model considers factors affecting accuracy, such as compass error, the effect of current, transducer drop error, transducer positioning effects, and ping interval. Mines can be placed at specific locations or generated randomly. Three types of vehicles are considered in this thesis. First, a simple vehicle that navigates by Dead Reckoning is analyzed. Second, a more complex vehicle that navigates using Long-Baseline (LBL) is analyzed. Third, the vehicle is simulated to move through an area of interest in a sweeping pattern that is populated by 10 mines, each of which is randomly positioned. Data from the last vehicle are used to build three analytic models that the operator can use to improve performance. First, the probability of detection is modeled by a logit regression. Second, given that detection has occurred, the mean location offset is modeled by a linear regression. Third, the distribution of errors is shown to follow an exponential distribution. These three models enable operators to explore the impact of various inputs prior to programming the vehicle, thus allowing them to choose the best combination of vehicle parameters that minimize the offset error between the reported and actual locations. (18 tables, 33 figures, 17 refs.)
Download or read book Obstacle Avoidance Control for the REMUS Autonomous Underwater Vehicle written by Christopher D. Chuhran and published by . This book was released on 2003-09 with total page 63 pages. Available in PDF, EPUB and Kindle. Book excerpt: As the Navy continues its development of unmanned underwater vehicles, the need for total autonomous missions grows. Autonomous Underwater Vehicles (AUV) allow for advances in mine warfare, harbor reconnaissance, undersea warfare and more. Information can be collected from AUVs and downloaded into a ship or battle group's network. As AUVs are developed it is clear forward-look sonar will be required to be able to detect obstacles in front of its search path. Common obstacles in the littoral environment include reefs and seawalls which an AUV will need to rise above to pass. This thesis examines the behavior and control system required for an AUV to maneuver over an obstacle in the vertical plane. Hydrodynamic modeling of a REMUS vehicle enables a series of equations of motion to be developed to be used in conjunction with a sliding mode controller to control the elevation of the AUV. A two-dimensional, 24 deg. vertical scan forward look sonar with a range of 100 m is modeled for obstacle detection. Sonar mappings from geographic range-bearing coordinates are developed for use in MATLAB simulations. The sonar 'image' of the vertical obstacle allows for an increasing altitude command that forces the AUV to pass safely over the obstacles at a reasonable rate of ascent and pitch angle. Once the AUV has passed over the obstacle, the vehicle returns to its regular search altitude. This controller is simulated over different types of obstacles.
Download or read book Reactive Obstacle Avoidance for the REMUS Autonomous Underwater Vehicle Utilizing a Forward Looking Sonar written by and published by . This book was released on 2006 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt: One day fully autonomous AUV's will no longer require human interactions to complete its missions. To make this a reality, the AUV must be able to safely navigate in unfamiliar environments with unknown obstacles. This thesis builds on previous work conducted at NPS's Center for AUV Research to improve the autonomy of the REMUS class of AUVs with an implemented FLS. The first part of this thesis deals with accurate path following with the use of look-ahead pitch calculations. With the use of a SIMULINK model, constraints surrounding obstacle avoidance path planning are then explored, focusing on optimal sensor orientation issues. Two path planning methods are developed to address the issues of a limited sonar field of view and uncertainties brought on by an occlusion area. The first approach utilizes a pop-up maneuver to increase the field of view and minimize the occlusion area, while the second approach creates a path with the addition of a spline. Comparing the two methods, it was concluded that spline addition planner provided a robust optimal obstacle avoidance path and along with the look-ahead pitch controller completes the design of a back-seat driver to improve REMUS s survivability in an unknown environment. REMUS, AUV, UUV, Autonomous Underwater Vehicle, Reactive Obstacle Avoidance, Forward Looking Sonar, Vertical Plane, Pitch Controller, Spline, Gaussian, Occlusion, Optimal Sensor Orientation.
Download or read book Obstacle Avoidance Control for the REMUS Autonomous Underwater Vehicle written by and published by . This book was released on 2002 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Future Naval operations necessitate the incorporation of autonomous underwater vehicles into a collaborative network. In future complex missions, a forward look capability will be required to map and avoid obstacles such as sunken ships. This thesis examines obstacle avoidance behaviors using a forward-looking sonar for the autonomous underwater vehicle REMUS. Hydrodynamic coefficients are used to develop steering equations that model REMUS through a track of specified points similar to a real-world mission track. Control of REMUS is accomplished using line of sight and state feedback controllers. A two-dimensional forward-looking sonar model with a 1200 horizontal scan and a 110 meter radial range is modeled for obstacle detection. Sonar mappings from geographic range-bearing coordinates are developed for implementation in MATLAE simulations. The product of bearing and range weighting functions form the gain factor for a dynamic obstacle avoidance behavior. The overall vehicle heading error incorporates this obstacle avoidance term to develop a path around detected objects. REMUS is a highly responsive vehicle in the model and is capable of avoiding multiple objects in proximity along its track path.
Download or read book Obstacle Avoidance While Bottom Following for the REMUS Autonomous Underwater Vehicle written by and published by . This book was released on 2004 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: Future Naval operations necessitate the incorporation of autonomous underwater vehicles into a collaborative network. In future complex missions, a forward look capability will also be required to map and avoid obstacles such as sunken ships and reefs. Following previous work on steering control, this work examines collision avoidance behaviors in bottom following using a hypothetical forward-looking sonar for the autonomous underwater vehicle REMUS. Hydrodynamic coefficients are used to develop diving equations that model REMUS behaviors. A two-dimensional forward-looking sonar model with a 20 vertical scan and a 40 meter radial range is modeled for obstacle detection. Sonar mappings from geographic range-bearing coordinates are developed for implementation in MATLAB simulations. REMUS is a highly responsive vehicle and care has taken to balance pitch and heave response to keep the obstacle to be avoided in sight during the response behavior.
Download or read book Obstacle Avoidance Control for the REMUS Autonomous Underwater Vehicle written by Lynn R. Fodrea and published by . This book was released on 2002-12 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt: Future Naval operations necessitate the incorporation of autonomous underwater vehicles into a collaborative network. In future complex missions, a forward look capability will be required to map and avoid obstacles such as sunken ships. This thesis examines obstacle avoidance behaviors using a forward- looking sonar for the autonomous underwater vehicle REMUS. Hydrodynamic coefficients are used to develop steering equations that model REMUS through a track of specified points similar to a real-world mission track. Control of REMUS is accomplished using line of sight and state feedback controllers. A two- dimensional forward-looking sonar model with a 1200 horizontal scan and a 110 meter radial range is modeled for obstacle detection. Sonar mappings from geographic range-bearing coordinates are developed for implementation in MATLAE simulations. The product of bearing and range weighting functions form the gain factor for a dynamic obstacle avoidance behavior. The overall vehicle heading error incorporates this obstacle avoidance term to develop a path around detected objects. REMUS is a highly responsive vehicle in the model and is capable of avoiding multiple objects in proximity along its track path.
Download or read book Obstacle Avoidance Control for the REMUS Autonomous Underwater Vehicle written by Lynn Fodrea and published by . This book was released on 2002 with total page 63 pages. Available in PDF, EPUB and Kindle. Book excerpt: Future Naval operations necessitate the incorporation of autonomous underwater vehicles into a collaborative network. In future complex missions, a forward look capability will be required to map and avoid obstacles such as sunken ships. This thesis examines obstacle avoidance behaviors using a forward-looking sonar for the autonomous underwater vehicle REMUS. Hydrodynamic coefficients are used to develop steering equations that model REMUS through a track of specified points similar to a real-world mission track. Control of REMUS is accomplished using line of sight and state feedback controllers. A two-dimensional forward-looking sonar model with a 1200 horizontal scan and a 110 meter radial range is modeled for obstacle detection. Sonar mappings from geographic range-bearing coordinates are developed for implementation in MATLAE simulations. The product of bearing and range weighting functions form the gain factor for a dynamic obstacle avoidance behavior. The overall vehicle heading error incorporates this obstacle avoidance term to develop a path around detected objects. REMUS is a highly responsive vehicle in the model and is capable of avoiding multiple objects in proximity along its track path.
Download or read book Vertical Plane Obstacle Avoidance and Control of the REMUS Autonomous Underwater Vehicle Using Forward Look Sonar written by and published by . This book was released on 2005 with total page 81 pages. Available in PDF, EPUB and Kindle. Book excerpt: Current rates of technological advancement continue to translate into changes on our battlefields. Aerial robots capable of gathering reconnaissance along with unmanned underwater vehicles capable of defusing enemy minefields provide evidence that machines are playing key roles once played by humans within our military. This thesis explores one of the major problems facing both commercial and military UUVs to date. Successfully navigating in unfamiliar environments and maneuvering autonomously to avoid obstacles is a problem that has yet to be fully solved. Using a simulated 2-D ocean environment, the work of this thesis provides results of numerous REMUS simulations that model the vehicle s flight path over selected sea bottoms. Relying on a combination of sliding mode control and feedforward preview control, REMUS is able to locate obstacles such as seawalls using processed forward look sonar images. Once recognized, REMUS maneuvers to avoid the obstacle according to a Gaussian potential function. In summary, the integration of feedforward preview control and sliding mode control results in an obstacle avoidance controller that is not only robust, but also autonomous.
Download or read book Navigation and Target Localization Performance of the AUV Remote Environmental Measuring UnitS written by Christopher John Cassidy and published by . This book was released on 2000 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experiments with the REMUS AUV written by Matthew D. Phaneuf and published by . This book was released on 2004-06-01 with total page 77 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis centers on actual field operations and post-mission analysis of data acguired using a REMUS AUV operated by tbe Naval Postgraduate School center for Autonomous Underwater Vehicle Research. It was one of many platforms tbat were utilized for data collection during AOSN II, (Autonomous Oceanograpbic Sampling Network II), an ONR sponsored exercise for dynamic oceanograpnic data taking and model based analysis using adaptive sampling. Tbe vebicle's ability to collect oceanograpnic data consisting of conductivity, temperature, and salinity during tbis experiment is assessed and problem areas investigated. Of particular interest are the temperature and salinity profiles measured from long transect runs of 18 Km. length into tbe soutbern parts of Monterey Bay. Experimentation witn tne REMUS as a mine detection asset was also performed. Tbe design and development of the mine hunting experiment is discussed as well as its results and tneir analysis. Of particular interest in tbis portion of tne work is tne issue relating to repeatability and precision of contact localization, obtained from vehicle position and sidescan sonar measurements.
Download or read book Mobile Dockikng of REMUS 100 Equipped with USBL APS to an Unmanned Surface Vehicle written by Mario Miranda (II) and published by . This book was released on 2014 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: The overall objective of this work is to evaluate the ability of homing and docking an unmanned underwater vehicle (Hydroid REMUS 100 UUV) to a moving unmanned surface vehicle (Wave-Adaptive Modular Surface Vehicle USV) using a Hydroid Digital Ultra-Short Baseline (DUSBL) acoustic positioning system (APS), as a primary navigation source. An understanding of how the UUV can rendezvous with a stationary USV first is presented, then followed by a moving USV. Inherently, the DUSBL-APS is susceptible to error due to the physical phenomena of the underwater acoustic channel (e.g. ambient noise, attenuation and ray refraction). The development of an APS model has allowed the authors to forecast the UUV's position and the estimated track line of the USV as determined by the DUSBL acoustic sensor. In this model, focus is placed on three main elements: 1) the acoustic channel and sound ray refraction when propagating in an in-homogeneous medium; 2) the detection component of an ideal DUSBL-APS using the Neyman-Pearson criterion; 3) the signal-to-noise ratio (SNR) and receiver directivity impact on position estimation. The simulation tool is compared against actual open water homing results in terms of the estimated source position between the simulated and the actual USBL range and bearing information.
Download or read book Verification of a 6 degree of Freedom Simulation Model for the REMUS AUV written by Timothy Jason Prestero and published by . This book was released on 2001 with total page 127 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mproving the performance of modular, low-cost autonomous underwater vehicles (AUVs) in such applications as long-range oceanographic survey, autonomous docking, and shallow-water mine countermeasures requires improving the vehicles' maneuvering precision and battery life. These goals can be achieved through the improvement of the vehicle control system. A vehicle dynamics model based on a combination of theory and empirical data would provide an efficient platform for vehicle control system development, and an alternative to the typical trial-and-error method of vehicle control system field tuning. As there exists no standard procedure for vehicle modeling in industry, the simulation of each vehicle system represents a new challenge. Developed by von Alt and associates at the Woods Hole Oceanographic Institute, the REMUS AUV is a small, low-cost platform serving in a range of oceanographic applications. This thesis describes the development and verification of a six degree of freedom, non-linear simulation model for the REMUS vehicle, the first such model for this platform. In this model, the external forces and moments resulting from hydrostatics, hydrodynamic lift and drag, added mass, and the control inputs of the vehicle propeller and fins are all defined in terms of vehicle coefficients. This thesis describes the derivation of these coefficients in detail. The equations determining the coefficients, as well as those describing the vehicle rigid-body dynamics, are left in non-linear form to better simulate the inherently non-linear behavior of the vehicle. Simulation of the vehicle motion is achieved through numeric integration of the equations of motion. The simulator output is then checked against vehicle dynamics data collected in experiments performed at sea. The simulator is shown to accurately model the motion of the vehicle.
Download or read book Single Transponder Range Only Navigation Geometry STRONG Applied to REMUS Autonomous Under Water Vehicles written by Jasper Carl Hartsfield and published by . This book was released on 2005 with total page 125 pages. Available in PDF, EPUB and Kindle. Book excerpt: A detailed study was conducted to prove the concept of an iterative approach to single transponder navigation for REMUS Autonomous Underwater Vehicles (AUVs). Although the concept of navigation with one acoustic beacon is not new, the objective was to develop a computer algorithm that could eventually be integrated into the REMUS architecture. This approach uses a least squares fit routine coupled with restrictive geometry and simulated annealing vice Kalman filtering and state vectors. In addition, to provide maximum flexibility, the single transponder was located on a GPS equipped surface ship that was free to move instead of the more common single bottom mounted beacon. Using only a series of spread spectrum ranges logged with time stamp, REMUS standard vehicle data, and reasonable initial conditions, the position at a later time was derived with a figure of merit fit score. Initial investigation was conducted using a noise model developed to simulate the errors suspected with the REMUS sensor suite. Results of this effort were applied to a small at sea test in 3,300 meters with the REMUS 6000 deep water AUV. A more detailed test was executed in Buzzard's Bay, Massachusetts, in 20 meters of water with a REMUS 100 AUV focusing on navigation in a typical search box. While deep water data was too sparse to reveal conclusive results, the Buzzard's Bay work strongly supports the premise that an iterative algorithm can reliably integrate REMUS logged data and an accurate time sequence of ranges to provide position fixes through simple least squares fitting. Ten navigational legs up to1500 meters in length showed that over 90% of radial position error can be removed from an AUV's position estimate using the STRONG algorithm vice dead reckon navigation with a magnetic compass and Doppler Velocity Log alone (DVL).
Download or read book Oceanography and Mine Warfare written by National Research Council and published by National Academies Press. This book was released on 2000-03-07 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt: Environmental information is important for successful planning and execution of naval operations. A thorough understanding of environmental variability greatly increases the likelihood of mission success. To ensure that naval forces have the most up-to-date capabilities, the Office of Naval Research (ONR) has an extensive environmental research program. This research, to be of greatest use to the warfighter, needs to be directed towards assisting and solving battlefield problems. To increase research community understanding of the operational demands placed on naval operators and to facilitate discussion between these two groups, the National Research Council's (NRC) Ocean Studies Board (OSB), working with ONR and the Office of the Oceanographer of the Navy, convened five previous symposia on tactical oceanography. Oceanography and Mine Warfare examines the following issues: (1) how environmental data are used in current mine warfare doctrine, (2) current procedures for in situ collection of data, (3) the present capabilities of the Navy's oceanographic community to provide supporting information for mine warfare operations, and (4) the ability of oceanographic research and technology developments to enhance current mine warfare capabilities. This report primarily concentrates on the importance of oceanographic data for mine countermeasures.
Download or read book Real time Coastal Observing Systems for Marine Ecosystem Dynamics and Harmful Algal Blooms written by Babin, Marcel and published by UNESCO. This book was released on 2008-06-05 with total page 880 pages. Available in PDF, EPUB and Kindle. Book excerpt: The proliferation of harmful phytoplankton in marine ecosystems can cause massive fish kills, contaminate seafood with toxins, impact local and regional economies and dramatically affect ecological balance. Real-time observations are essential for effective short-term operational forecasting, but observation and modelling systems are still being developed. This volume provides guidance for developing real-time and near real-time sensing systems for observing and predicting plankton dynamics, including harmful algal blooms, in coastal waters. The underlying theory is explained and current trends in research and monitoring are discussed.Topics covered include: coastal ecosystems and dynamics of harmful algal blooms; theory and practical applications of in situ and remotely sensed optical detection of microalgal distributions and composition; theory and practical applications of in situ biological and chemical sensors for targeted species and toxin detection; integrated observing systems and platforms for detection; diagnostic and predictive modelling of ecosystems and harmful algal blooms, including data assimilation techniques; observational needs for the public and government; and future directions for research and operations.
Download or read book Autonomy and Unmanned Vehicles written by Somaiyeh MahmoudZadeh and published by Springer. This book was released on 2018-08-06 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book addresses higher–lower level decision autonomy for autonomous vehicles, and discusses the addition of a novel architecture to cover both levels. The proposed framework’s performance and stability are subsequently investigated by employing different meta-heuristic algorithms. The performance of the proposed architecture is shown to be largely independent of the algorithms employed; the use of diverse algorithms (subjected to the real-time performance of the algorithm) does not negatively affect the system’s real-time performance. By analyzing the simulation results, the book demonstrates that the proposed model provides perfect mission timing and task management, while also guaranteeing secure deployment. Although mainly intended as a research work, the book’s review chapters and the new approaches developed here are also suitable for use in courses for advanced undergraduate or graduate students.
Download or read book Proceedings of the 11th National Technical Seminar on Unmanned System Technology 2019 written by Zainah Md Zain and published by Springer Nature. This book was released on 2020-07-07 with total page 1239 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book includes research papers from the 11th National Technical Symposium on Unmanned System Technology. Covering a number of topics, including intelligent robotics, novel sensor technology, control algorithms, acoustics signal processing, imaging techniques, biomimetic robots, green energy sources, and underwater communication backbones and protocols, it will appeal to researchers developing marine technology solutions and policy-makers interested in technologies to facilitate the exploration of coastal and oceanic regions.
