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(1 - 13 of 13)
- Title
- Design of an adaptive nonlinear controller for an autonomous underwater vehicle equipped with a vectored thruster.
- Creator
- Morel, Yannick., Florida Atlantic University, Leonessa, Alexander, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
The tasks Autonomous Underwater Vehicles (AUVs) are expected to perform are becoming more and more challenging. Thus, to be able to address such tasks, we implemented a high maneuverability propulsion system: a vectored thruster. The design of a vehicle equipped with such a propulsion system will be presented, from a mechanical, electronic and software point of view. The motion control of the resulting system is fairly complex, and no suitable controller is available in the literature....
Show moreThe tasks Autonomous Underwater Vehicles (AUVs) are expected to perform are becoming more and more challenging. Thus, to be able to address such tasks, we implemented a high maneuverability propulsion system: a vectored thruster. The design of a vehicle equipped with such a propulsion system will be presented, from a mechanical, electronic and software point of view. The motion control of the resulting system is fairly complex, and no suitable controller is available in the literature. Accordingly, we will present the derivation of a novel tracking controller, whose adaptive properties will compensate for the lack of knowledge of the system's parameters. Computer simulations are provided and show the performance and robustness of the proposed control algorithm to external perturbations, unmodelled dynamics and dynamics variation. We finally illustrate the advantage of using an adaptive controller by comparing the presented controller to a Proportional Integral Derivative controller.
Show less - Date Issued
- 2002
- PURL
- http://purl.flvc.org/fcla/dt/12986
- Subject Headings
- Hydrodynamics, Nonlinear control theory, Adaptive control systems, Oceanographic submersibles
- Format
- Document (PDF)
- Title
- A precision navigation system for autonomous undersea vehicles.
- Creator
- White, Dan G., Psota, F., Harbor Branch Oceanographic Institute
- Date Issued
- 1996
- PURL
- http://purl.flvc.org/FCLA/DT/3351964
- Subject Headings
- Inertial navigation systems, Submersibles, Submersibles--Automatic control, Inertial navigation, Remote submersibles
- Format
- Document (PDF)
- Title
- Automated Launch and Recovery of an Autonomous Underwater Vehicle from an Unmanned Surface Vessel.
- Creator
- Sarda, Edoardo I, Dhanak, Manhar R., Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
Research on collaboration among unmanned platforms is essential to improve the applications for autonomous missions, by expanding the working environment of the robotic systems, and reducing the risks and the costs associated with conducting manned operations. This research is devoted to enable the collaboration between an Unmanned Surface Vehicle (USV) and an Autonomous Underwater Vehicle (AUV), by allowing the first one to launch and recover the second one. The objective of this...
Show moreResearch on collaboration among unmanned platforms is essential to improve the applications for autonomous missions, by expanding the working environment of the robotic systems, and reducing the risks and the costs associated with conducting manned operations. This research is devoted to enable the collaboration between an Unmanned Surface Vehicle (USV) and an Autonomous Underwater Vehicle (AUV), by allowing the first one to launch and recover the second one. The objective of this dissertation is to identify possible methods to launch and recover a REMUS 100 AUV from a WAM-V 16 USV, thus developing this capability by designing and implementing a launch and recovery system (LARS). To meet this objective, a series of preliminary experiments was first performed to identify two distinct methods to launch and recover the AUV: mobile and semi-stationary. Both methods have been simulated using the Orcaflex software. Subsequently, the necessary control systems to create the mandatory USV autonomy for the purpose of launch and recovery were developed. Specifically, a series of low-level controllers were designed and implemented to enable two autonomous maneuvers on the USV: station-keeping and speed & heading control. In addition, a level of intelligence to autonomously identify the optimal operating conditions within the vehicles' working environment, was derived and integrated on the USV. Lastly, a LARS was designed and implemented on the vehicles to perform the operation following the proposed methodology. The LARS and all subsystems developed for this research were extensively tested through sea-trials. The methodology for launch and recovery, the design of the LARS and the experimental findings are reported in this document.
Show less - Date Issued
- 2016
- PURL
- http://purl.flvc.org/fau/fd/FA00004631, http://purl.flvc.org/fau/fd/FA00004631
- Subject Headings
- Underwater acoustic telemetry., Fuzzy systems., Nonlinear control theory., Adaptive signal processing., Oceanographic submersibles--Automatic control., Submersibles--Control systems.
- Format
- Document (PDF)
- Title
- A high-level fuzzy logic guidance system for an unmanned surface vehicle (USV) tasked to perform an autonomous launch and recovery (ALR) of an unmanned underwater vehicle (UUV).
- Creator
- Pearson, David, An, Pak-Cheung, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
There have been much technological advances and research in Unmanned Surface Vehicles (USV) as a support and delivery platform for Autonomous/Unmanned Underwater Vehicles (AUV/UUV). Advantages include extending underwater search and survey operations time and reach, improving underwater positioning and mission awareness, in addition to minimizing the costs and risks associated with similar manned vessel operations. The objective of this thesis is to present the design and development a high...
Show moreThere have been much technological advances and research in Unmanned Surface Vehicles (USV) as a support and delivery platform for Autonomous/Unmanned Underwater Vehicles (AUV/UUV). Advantages include extending underwater search and survey operations time and reach, improving underwater positioning and mission awareness, in addition to minimizing the costs and risks associated with similar manned vessel operations. The objective of this thesis is to present the design and development a high-level fuzzy logic guidance controller for a WAM-V 14 USV in order to autonomously launch and recover a REMUS 100 AUV. The approach to meeting this objective is to develop ability for the USV to intercept and rendezvous with an AUV that is in transit in order to maximize the probability of a final mobile docking maneuver. Specifically, a fuzzy logic Rendezvous Docking controller has been developed that generates Waypoint-Heading goals for the USV to minimize the cross-track errors between the USV and AUV. A subsequent fuzzy logic Waypoint-Heading controller has been developed to provide the desired heading and speed commands to the low-level controller given the Waypoint-Heading goals. High-level mission control has been extensively simulated using Matlab and partially characterized in real-time during testing. Detailed simulation, experimental results and findings will be reported in this paper.
Show less - Date Issued
- 2014
- PURL
- http://purl.flvc.org/fau/fd/FA00004315, http://purl.flvc.org/fau/fd/FA00004315
- Subject Headings
- Adaptive signal processing, Fuzzy sets, Fuzzy systems, Nonlinear control theory, Oceanographic submersibles -- Automatic control, Submersibles -- Control systems, Underwater acoustic telemetry
- Format
- Document (PDF)
- Title
- A fuzzy logic based flight control system for the FAU "Ocean Voyager" autonomous underwater vehicle.
- Creator
- Anderson, Donald Taylor., Florida Atlantic University, Smith, Samuel M.
- Abstract/Description
-
The development of a Flight Control System for a non-linear six degree of freedom model of an Autonomous Underwater Vehicle is described. Heading, pitch and depth are regulated by three independent Fuzzy Logic Controllers (FLCs). Numerical methods are used to tune rule bases to control tables that are based on the minimum time characteristics of the model. Setpoint errors are eliminated using fuzzily constrained integrators. A scheme to vary control policy with forward speed is also detailed....
Show moreThe development of a Flight Control System for a non-linear six degree of freedom model of an Autonomous Underwater Vehicle is described. Heading, pitch and depth are regulated by three independent Fuzzy Logic Controllers (FLCs). Numerical methods are used to tune rule bases to control tables that are based on the minimum time characteristics of the model. Setpoint errors are eliminated using fuzzily constrained integrators. A scheme to vary control policy with forward speed is also detailed. System stability is evaluated using cell-to-cell mapping. A variable structure fuzzy heading controller is designed for an unstable non-linear model of an Unmanned Underwater Vehicle. Scheduling of scaling parameters accommodates changes in forward speed as predicted by thruster RPM and angular distance turned. This FLC combines bang-bang and linear type control to respond more rapidly and robustly than a gain scheduled linear PID controller.
Show less - Date Issued
- 1993
- PURL
- http://purl.flvc.org/fcla/dt/14899
- Subject Headings
- Fuzzy sets, Submersibles--Control systems, Oceanographic submersibles--Automatic control
- Format
- Document (PDF)
- Title
- A force sensor system for the real time measurement of thrust on an AUV.
- Creator
- Larroque-Lahitette, Gilles., Florida Atlantic University, Holappa, Kenneth W., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
When a control system for an Autonomous Underwater Vehicle (AUV) requires thrust, it is common to apply a simplified model to estimate the force generated. Even though this model takes into account several parameters, it will never recover the real value. Our challenge is to directly measure the force, in real time, from the tunnel thrusters used in the positioning control of the Mini AUV known as Morpheus. Therefore, a force sensor system has been designed, optimized, machined and tested,...
Show moreWhen a control system for an Autonomous Underwater Vehicle (AUV) requires thrust, it is common to apply a simplified model to estimate the force generated. Even though this model takes into account several parameters, it will never recover the real value. Our challenge is to directly measure the force, in real time, from the tunnel thrusters used in the positioning control of the Mini AUV known as Morpheus. Therefore, a force sensor system has been designed, optimized, machined and tested, that supports the thruster assembly. The sensor implements strain gages to measure the deformation in a beam. To optimize the capabilities of the sensor, a finite elements analysis has been run. The sensor has been fabricated and tested to determine the static and dynamic characteristics. This thesis discusses the design implementation, optimization, fabrication and testing of the force sensor. The discussion begins with an overview of the problem, then explains the fabrication, optimization, testing and concludes with recommendation for future work.
Show less - Date Issued
- 2001
- PURL
- http://purl.flvc.org/fcla/dt/12745
- Subject Headings
- Oceanographic submersibles, Tactile sensors, Robots--Control systems
- Format
- Document (PDF)
- Title
- Statistical bounds on handoff probabilities under different fading channel models of mobile communication.
- Creator
- Laupattarakasem, Pet., Florida Atlantic University, Neelakanta, Perambur S., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
The research envisaged and reported in this thesis refers to finding comprehensive algorithms to determine the handoff probabilities of new and handoff calls encountered in mobile communications. The traditional expressions for these probabilities that are reported in the literature, are deduced only on the basis of call arrival statistics applied to RF links between base station (BS) and the mobile unit (MU). However, such radio links inevitably suffer from fading. These channels are...
Show moreThe research envisaged and reported in this thesis refers to finding comprehensive algorithms to determine the handoff probabilities of new and handoff calls encountered in mobile communications. The traditional expressions for these probabilities that are reported in the literature, are deduced only on the basis of call arrival statistics applied to RF links between base station (BS) and the mobile unit (MU). However, such radio links inevitably suffer from fading. These channels are normally modeled by appropriate probability density functions (pdfs) of the faded signal envelope. Rayleigh, Rician and Nakagami-m distributions are popularly considered in depicting such fading channel characteristics. The traditional (queueing-theoretic) based estimation of handoff probabilities does not account for the hysteresis-specific handoff statistics in the relevant fading channels. This is in contrary to the reality, inasmuch as fading is an inherent part of RF channels in mobile communications. The present study offers a tractable method of combining queuing-theoretic (call arrival) statistics and the hysteresis-crossing statistics of a RSS metric so as to obtain proper expressions for new and handoff call handoff probabilities. The (upper and lower) bound specified spread of the handoff probabilities indicates that care should be exercised in resource allocation efforts with a margin. To the best of the knowledge of the author, this research exercise is new and has not been reported elsewhere in open literature.
Show less - Date Issued
- 2003
- PURL
- http://purl.flvc.org/fcla/dt/13006
- Subject Headings
- Oceanographic submersibles, Tactile sensors, Robots--Control systems
- Format
- Document (PDF)
- Title
- Leveled flight control of an unmanned underwater vehicle operating in a wave induced environment.
- Creator
- Potesta, Joshua J., An, Edgar, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
Autonomous Underwater Vehicle (AUV) depth control methods typically use a pressure sensor to measure the depth, which results in the AUV following the trajectory of the surface waves. Through simulations, a controller is designed for the Ocean Explorer AUV with the objective of the AUV holding a constant depth below the still water line while operating in waves. This objective is accomplished by modeling sensors and using filtering techniques to provide the AUV with the depth below the still...
Show moreAutonomous Underwater Vehicle (AUV) depth control methods typically use a pressure sensor to measure the depth, which results in the AUV following the trajectory of the surface waves. Through simulations, a controller is designed for the Ocean Explorer AUV with the objective of the AUV holding a constant depth below the still water line while operating in waves. This objective is accomplished by modeling sensors and using filtering techniques to provide the AUV with the depth below the still water line. A wave prediction model is simulated to provide the controller with knowledge of the wave disturbance before it is encountered. The controller allows for depth keeping below the still water line with a standard deviation of 0.04 and 0.65 meters for wave amplitudes of 0.1-0.25 and 0.5-2 meters respectively and wave frequencies of 0.35-1.0 πππβπ ππ, and the wave prediction improves the depth control on the order of 0.03 meters.
Show less - Date Issued
- 2014
- PURL
- http://purl.flvc.org/fau/fd/FA00004149, http://purl.flvc.org/fau/fd/FA00004149
- Subject Headings
- Feedback control systems, Nonlinear control theory, Remote submersibles -- Design and construction, Vehicles, Remotely piloted -- Mathematical models
- Format
- Document (PDF)
- Title
- Optical 2D Positional Estimation for a Biomimetic Station-Keeping Autonomous Underwater Vehicle.
- Creator
- Nunes, Christopher, Dhanak, Manhar R., Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
Underwater vehicles often use acoustics or dead reckoning for global positioning, which is impractical for low cost, high proximity applications. An optical based positional feedback system for a wave tank operated biomimetic station-keeping vehicle was made using an extended Kalman filter and a model of a nearby light source. After physical light model verification, the filter estimated surge, sway, and heading with 6 irradiance sensors and a low cost inertial measurement unit (~$15)....
Show moreUnderwater vehicles often use acoustics or dead reckoning for global positioning, which is impractical for low cost, high proximity applications. An optical based positional feedback system for a wave tank operated biomimetic station-keeping vehicle was made using an extended Kalman filter and a model of a nearby light source. After physical light model verification, the filter estimated surge, sway, and heading with 6 irradiance sensors and a low cost inertial measurement unit (~$15). Physical testing with video feedback suggests an average error of ~2cm in surge and sway, and ~3deg in yaw, over a 1200 cm2 operational area. This is 2-3 times better, and more consistent, than adaptations of prior art tested alongside the extended Kalman filter feedback system. The physical performance of the biomimetic platform was also tested. It has a repeatable forward velocity response with a max of 0.3 m/s and fair stability in surface testing conditions.
Show less - Date Issued
- 2015
- PURL
- http://purl.flvc.org/fau/fd/FA00004528, http://purl.flvc.org/fau/fd/FA00004528
- Subject Headings
- Biometric identification, Feedback control systems, Oceanographic submersibles -- Design and construction, OpticalΒ pattern recognition, Remote submersibles -- Design and construction
- Format
- Document (PDF)
- Title
- A robust AUV docking guidance and navigation approach to handling unknown current disturbances.
- Creator
- Teo, Hoe Eng., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
The main contribution in this thesis is the design of a robust AUV docking guidance and navigation approach that can guide and home an AUV towards an acoustic source located on an oriented bottom-mounted underwater docking station, under presence of unknown current disturbances and in the absence of any form of onboard velocity sensor. A Complementary Filter and various forms of Kalman Filters were separately formulated to estimate the current and vehicle positions with strategic vehicle...
Show moreThe main contribution in this thesis is the design of a robust AUV docking guidance and navigation approach that can guide and home an AUV towards an acoustic source located on an oriented bottom-mounted underwater docking station, under presence of unknown current disturbances and in the absence of any form of onboard velocity sensor. A Complementary Filter and various forms of Kalman Filters were separately formulated to estimate the current and vehicle positions with strategic vehicle manoeuvres. A current compensator uses the estimated current to maintain the desired vehicle course while under current disturbance. Tagaki-Sugeno-Kang Fuzzy Inference System was designed to realize fuzzy docking guidance manoeuvres. Finally, Monte Carlo runs were performed on a designed AUV docking simulator to evaluate the docking robustness against various docking conditions. Simulation results demonstrated robustness in the designed docking guidance and navigation approach.
Show less - Date Issued
- 2010
- PURL
- http://purl.flvc.org/FAU/2683137
- Subject Headings
- Oceanographic submersibles, Computer simulation, Underwater navigation, Fuzzy systems, Automatic control, Mathematical models
- Format
- Document (PDF)
- Title
- A fuzzy logic material selection methodology for renewable ocean energy applications.
- Creator
- Welling, Donald Anthony., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
The purpose of this thesis is to develop a renewable ocean energy material selection methodology for use in FAU's Ocean Energy Projects. A detailed and comprehensive literature review has been performed concerning all relevant material publications and forms the basis of the developed method. A database of candidate alloys has been organized and is used to perform case study material selections to validate the developed fuzzy logic approach. The ultimate goal of this thesis is to aid in the...
Show moreThe purpose of this thesis is to develop a renewable ocean energy material selection methodology for use in FAU's Ocean Energy Projects. A detailed and comprehensive literature review has been performed concerning all relevant material publications and forms the basis of the developed method. A database of candidate alloys has been organized and is used to perform case study material selections to validate the developed fuzzy logic approach. The ultimate goal of this thesis is to aid in the selection of materials that will ensure the successful performance of renewable ocean energy projects so that clean and renewable energy becomes a reality for all.
Show less - Date Issued
- 2009
- PURL
- http://purl.flvc.org/FAU/227980
- Subject Headings
- Oceanic submersibles, Control systems, Acoustical engineering, Fuzzy algorithms, Renewable energy sources
- Format
- Document (PDF)
- Title
- Dynamics and Control of Autonomous Underwater Vehicles with Internal Actuators.
- Creator
- Li, Bo, Su, Tsung-Chow, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
This dissertation concerns the dynamics and control of an autonomous underwater vehicle (AUV) which uses internal actuators to stabilize its horizontalplane motion. The demand for high-performance AUVs are growing in the field of ocean engineering due to increasing activities in ocean exploration and research. New generations of AUVs are expected to operate in harsh and complex ocean environments. We propose a hybrid design of an underwater vehicle which uses internal actuators instead of...
Show moreThis dissertation concerns the dynamics and control of an autonomous underwater vehicle (AUV) which uses internal actuators to stabilize its horizontalplane motion. The demand for high-performance AUVs are growing in the field of ocean engineering due to increasing activities in ocean exploration and research. New generations of AUVs are expected to operate in harsh and complex ocean environments. We propose a hybrid design of an underwater vehicle which uses internal actuators instead of control surfaces to steer. When operating at low speeds or in relatively strong ocean currents, the performances of control surfaces will degrade. Internal actuators work independent of the relative ows, thus improving the maneuvering performance of the vehicle. We develop the mathematical model which describes the motion of an underwater vehicle in ocean currents from first principles. The equations of motion of a body-fluid dynamical system in an ideal fluid are derived using both Newton-Euler and Lagrangian formulations. The viscous effects of a real fluid are considered separately. We use a REMUS 100 AUV as the research model, and conduct CFD simulations to compute the viscous hydrodynamic coe cients with ANSYS Fluent. The simulation results show that the horizontal-plane motion of the vehicle is inherently unstable. The yaw moment exerted by the relative flow is destabilizing. The open-loop stabilities of the horizontal-plane motion of the vehicle in both ideal and real fluid are analyzed. In particular, the effects of a roll torque and a moving mass on the horizontal-plane motion are studied. The results illustrate that both the position and number of equilibrium points of the dynamical system are prone to the magnitude of the roll torque and the lateral position of the moving mass. We propose the design of using an internal moving mass to stabilize the horizontal-plane motion of the REMUS 100 AUV. A linear quadratic regulator (LQR) is designed to take advantage of both the linear momentum and lateral position of the internal moving mass to stabilize the heading angle of the vehicle. Alternatively, we introduce a tunnel thruster to the design, and use backstepping and Lyapunov redesign techniques to derive a nonlinear feedback control law to achieve autopilot. The coupling e ects between the closed-loop horizontal-plane and vertical-plane motions are also analyzed.
Show less - Date Issued
- 2016
- PURL
- http://purl.flvc.org/fau/fd/FA00004738, http://purl.flvc.org/fau/fd/FA00004738
- Subject Headings
- Dynamics., Remote submersibles--Design and construction., Ocean engineering., Fluid dynamics., Nonlinear control theory., Differentiable dynamical systems.
- Format
- Document (PDF)
- Title
- Design and Deployment Analysis of Morphing Ocean Structure.
- Creator
- Li, Yanjun, Su, Tsung-Chow, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
As humans explore greater depths of Earthβs oceans, there is a growing need for the installation of subsea structures. 71% of the earthβs surface is ocean but there are limitations inherent in current detection instruments for marine applications leading to the need for the development of underwater platforms that allow research of deeper subsea areas. Several underwater platforms including Autonomous Underwater Vehicles (AUVs), Remote Operated Vehicles (ROVs), and wave gliders enable more...
Show moreAs humans explore greater depths of Earthβs oceans, there is a growing need for the installation of subsea structures. 71% of the earthβs surface is ocean but there are limitations inherent in current detection instruments for marine applications leading to the need for the development of underwater platforms that allow research of deeper subsea areas. Several underwater platforms including Autonomous Underwater Vehicles (AUVs), Remote Operated Vehicles (ROVs), and wave gliders enable more efficient deployment of marine structures. Deployable structures are able to be compacted and transported via AUV to their destination then morph into their final form upon arrival. They are a lightweight, compact solution. The wrapped package includes the deployable structure, underwater pump, and other necessary instruments, and the entire package is able to meet the payload capability requirements. Upon inflation, these structures can morph into final shapes that are a hundred times larger than their original volume, which extends the detection range and also provides long-term observation capabilities. This dissertation reviews underwater platforms, underwater acoustics, imaging sensors, and inflatable structure applications then proposes potential applications for the inflatable structures. Based on the proposed applications, a conceptual design of an underwater tubular structure is developed and initial prototypes are built for the study of the mechanics of inflatable tubes. Numerical approaches for the inflation process and bending loading are developed to predict the inflatable tubular behavior during the structureβs morphing process and under different loading conditions. The material properties are defined based on tensile tests. The numerical results are compared with and verified by experimental data. The methods used in this research provide a solution for underwater inflatable structure design and analysis. Several ocean morphing structures are proposed based on the inflatable tube analysis.
Show less - Date Issued
- 2016
- PURL
- http://purl.flvc.org/fau/fd/FA00004752, http://purl.flvc.org/fau/fd/FA00004752
- Subject Headings
- Air-supported structures--Design and construction., Remote submersibles--Design and construction., Tensile architecture., Fluid mechanics., Structural dynamics., Ocean engineering., Adaptive control systems.
- Format
- Document (PDF)
