Autonomous Underwater Vehicle

Straight-ahead resistance tests and static-yaw runs up to 20°yaw angle for the axi-symmetric bare hull configurations of the ''Phoenix'' underwater vehicle that were performed in the 90 m towing tank at the Institute for Ocean Technology, National Research Council, Canada, provided empirical formulae for the drag force, lift force and turning moment that are exerted on such axi-symmetric torpedo-shaped hull forms. The empirical formulae were then embedded in a numerical code to simulate the constant-depth planar manoeuvres of the MUN Explorer autonomous underwater vehicle (AUV). The simulation model was first calibrated using the sea-trial data, and then was used to study the turning manoeuvres and to compare the simulation results with those from theoretical formulae based on the linearized equations of motion. The simulation results show non-linear changes in the hydrodynamic coefficients as the turning manoeuvre becomes tighter.

Underwater environments are highly unstructured, uncertain, and dynamic. However, over the past three decades many autonomous underwater vehicles (AUVs) have been developed and successfully deployed for various oceanographic applications. There is a growing need for the AUVs to be reliable for collecting useful data and samples for their users. An AUV is a typical one-of-a-kind product for which it is difficult to derive a mathematical/ statistical model for reliability prediction. The failure modes effects and criticality analysis (FM€CA) can produce more effective results. However, the assessment of reliability growth of an AUV is very important for predicting its operational success in challenging underwater environments. In this paper, we present the identification of different types of failures that occurred during the past one and a half years of operation of MBARlk Dorado AUV, classification of those failures, and the reliability growth analysis for the vehicle. Reliability issues of various subsystems and operational procedure of the AUV have also been discussed. A n extensive analysis of operational data and test results are presented in this paper.

One of the major applications of underwater acoustic sensor networks (UWASN) is ocean environment monitoring. Employing data mules is an energy efficient way of data collection from the underwater sensor nodes in such a network. A data mule node such as an autonomous underwater vehicle (AUV) periodically visits the stationary nodes to download data. By conserving the power required for

Efficient path planning algorithms are a crucial issue for modern autonomous underwater vehicles. Classical path planning algorithms in artificial intelligence are not designed to deal with wide continuous environments prone to currents. We present a novel Fast Marching based approach to address the following issues. First, we develop an algorithm we call FM* to efficiently extract a continuous path from a discrete representation of the environment. Secondly we take underwater currents into account thanks to an anisotropic extension of the original Fast Marching algorithm. Thirdly, the vehicle turning radius is introduced as a constraint on the optimal path curvature for both isotropic and anisotropic medias. Finally, a multiresolution method is introduced to speed up the overall path planning process.

There are problems controlling autonomous underwater vehicles (AUVs) because they are nonlinear and coupled and have external environmental disturbances acting on the vehicle. More difficulties arise when the vehicle tasks require precise positioning and control as in military missions. This paper presents an integrated guidance and control method for an AUV. The algorithm is based on an optimal control method called shrinking horizon model predictive control (SHMPC). Scenarios for reconnaissance and reacquisition in mine countermeasures missions are explored applying SHMPC. In addition, there are scenarios with obstacle avoidance. Simulations of this method show the control method is able to systematically handle disturbances and constraints to successfully maneuver through volatile areas.

Underwater glider is an autonomous underwater vehicle that glides by controlling their buoyancy and attitude using internal actuators. By changing the vehicle's buoyancy intermittently, vertical motion can be achieved. Characteristics of glider motion include upward and downward movement in a saw tooth pattern, turning and gliding in a vertical spiral motion and gliding without using thrusters or propellers. This paper presents the modelling and identification on net buoyancy, depth and pitching angle of an underwater glider system. A ballast tank subsystem is considered appropriate for the identification process since it is the main parameter for the motion control. By selecting the ballast rate as the input, three aspects of the dynamics of a glider can be observed: buoyancy, depth of the glider and pitching angle. The MATLAB System Identification Toolbox TM is used to obtain a mathematical model of the glider ballast-buoyancy, ballast-depth and ballast-pitching angle conditioning system. The best three parametric estimation models are chosen, and the results of the comparison between simulated and estimated outputs are presented. The information obtained from the modelling and identification approaches are used for USM's Underwater Glider Prototype controller design. The information observed during this procedure are utilised for optimisation, stability, reliability and robustness analysis of the underwater glider.

This article introduces the reader to a new generation of ocean data platforms known as Autonomous Underwater Vehicles (or AUVs) brought about by promising technology developments in new sensors, memories, embedded controllers and materials. There has been a growing interest by oil and gas exploration industry in using deep water AUVs to map bathymetry around an oil well head, by the navy in mine surveillance or intelligence gathering, and abundant activity by the scientific and engineering communities scattered in several dozen universities and research establishments around the globe in building their own versions of AUVs for scientific data collection. In order to demystify the notion that AUVs are complex, high technology devices, we include a description of the main building blocks that go into the design of an AUV. This is followed by a brief look at the current scenario in AUV developments, but narrowing our attention to three noteworthy operational AUVs, and to our ongoing development of a small AUV at the National Institute of Oceanography, Goa. The ultimate aim in AUV research and development is to reach the stage of unescorted missions that will see AUVs leaving and entering the world's harbours autonomously or doing the same from the shore. We shall see that this implies the implementation of safety standards of a high degree in a stable, well-tested and reliable vehicle architecture.

This paper describes ROV (Remotely Operated Vehicle) that can take sample of contaminated water and soil while the operator operates it on the shore or ship. User can operate ROV wirelessly. ROV is equipped with camera, robot hand, GPS, accelerometer, compass, and other devices. The ROV is aimed to help researchers to research contaminated water and soil that can be applied in and on the lake, river, and sea. The way it operates are syphoning water with mini pump and taking soil sample with robot hand. The result shows that all hardware and software can run well underwater. So that, ROV in this experiment can be used to take sample of contaminated water and soil in the place with maximum a depth of 1m. For the next experiment, this ROV will be tested in other place with a depth more than 1m. however, this ROV will continue to be refined to be maximally utilized. the total paddy field (983 Ha) in the fourth villages with a yield of around 0.50-0.60 tons GK / H were

We report results from an investigation of the geologic processes controlling hydrothermal activity along the previously-unstudied southern Mid-Atlantic Ridge (3-7°S). Our study employed the NOC (UK) deep-tow sidescan sonar instrument, TOBI, in concert with the WHOI (USA) autonomous underwater vehicle, ABE, to collect information concerning hydrothermal plume distributions in the water column co-registered with geologic investigations of the underlying seafloor. Two areas of high-temperature hydrothermal venting were identified. The first was situated in a non-transform discontinuity (NTD) between two adjacent secondorder ridge-segments near 4°02′S, distant from any neovolcanic activity. This geologic setting is very similar to that of the ultramafic-hosted and tectonically-controlled Rainbow vent-site on the northern Mid-Atlantic Ridge. The second site was located at 4°48′S at the axial-summit centre of a second-order ridge-segment. There, high-temperature venting is hosted in an ∼ 18 km 2 area of young lava flows which in some cases are observed to have flowed over and engulfed pre-existing chemosynthetic vent-fauna. In both appearance and extent, these lava flows are directly reminiscent of those emplaced in Winter 2005−06 at the East Pacific Rise, 9°50′N and reference to global seismic catalogues reveals that a swarm of large (M 4.6−5.6) seismic events was centred on the 5°S segment over a ∼ 24 h period in late June 2002, perhaps indicating the precise timing of this volcanic eruptive episode. Temperature measurements at one of the vents found directly adjacent to the fresh lava flows at 5°S MAR (Turtle Pits) have subsequently revealed vent-fluids that are actively phase separating under conditions very close to the Critical Point for seawater, at ∼ 3000 m depth and 407°C: the hottest vent-fluids yet reported from anywhere along the global ridge crest.

An important issue in the preliminary design of Autonomous Underwater Vehicles (AUV) is the selection of the optimal dimensions for the vehicle (sizing). These dimensions are dependent on the characteristics of the mission, the operating environment and the chosen technology. This paper presents a computer-based design-tool, which integrates all major design parameters to allow an efficient and rapid trade-off analysis between various options, for example different battery types, etc. In order to carry out fast modelling, different types of battery, fuel cell and semifuel cell options to power the AUV are pre-programmed in the dimensioning module and can be selected by the designer. An integral part of the vehicle design is sustainability and this can be determined by performing a Life Cycle Assessment (LCA) on the vehicle. LCA refers to the compilation and evaluation of the inputs, outputs and the potential environmental impacts of a product system throughout its life cycle). For this purpose the SimaPro® system is used to model a modular AUV as a function of its external dimensions and the type of power supply. When the user is satisfied with the designed vehicle, the program can calculate the hydrodynamic variables of the vehicle and load these variables into the vehicle simulation package (DSTO V-Sim).

The goal of adaptive sampling in the ocean is to predict the types and locations of additional ocean measurements that would be most useful to collect. Quantitatively, what is most useful is defined by an objective function and the goal is then to optimize this objective under the constraints of the available observing network. Examples of objectives are better oceanic understanding, to improve forecast quality, or to sample regions of high interest. This work provides a new path-planning scheme for the adaptive sampling problem. We ...

There is increasing interest from the marine science community in using autonomous underwater vehicles (AUVs) under ice shelves and under sea ice. These environments pose challenges to the vehicle and support team, and they mean that recovery may be almost impossible, or very expensive, should the vehicle develop a fault particularly when beneath ice. This paper reviews recent published work on AUV reliability and develops a risk management process (RMP-AUV) tuned to the needs of the responsible owner working with a technical support team. The RMP-AUV provides a framework for the responsible owner to determine an acceptable risk using mainly objective information, augmented with subjective judgement on the priority of the proposed vehicle campaigns. A process is defined whereby the technical team determines the probability of loss based on the most applicable historic data for the vehicle. If this is less than the risk acceptable to the owner, RMP-AUV then requires this assessment to be verified, for example through a proving campaign. How a campaign can be designed to meet this objective is discussed and other risk mitigation strategies are outlined. Worked examples are included to illustrate the how the proposed RMP-AUV would work, using actual reliability data from the Autosub AUV. We are some way from having sufficiently reliable (or sufficiently inexpensive) AUVs that the task of risk assessment in polar environments becomes trivial. Until that time careful performance and risk assessments will be needed. Furthermore, those assessments should be used to drive forward improvements in AUV reliability so that the full potential of autonomous systems to deliver data from the polar regions can be realised.

This paper discusses opportunities to parallelize graph based path planning algorithms in a time varying environment. Parallel architectures have become commonplace, requiring algorithm to be parallelized for efficient execution. An additional focal point of this paper is the inclusion of inaccuracies in path planning as a result of forecast error variance, accuracy of calculation in the cost functions and a different observed vehicle speed in the real mission than planned. In this context, robust path planning algorithms will be described. These algorithms are equally applicable to land based, aerial, or underwater mobile autonomous systems. The results presented here provide the basis for a future Research project in which the parallelized algorithms will be evaluated on multi and many core systems such as the dual core ARM Panda board and the 48 core Single-chip Cloud Computer (SCC). Modern multi and many core processors support a wide range of performance vs. energy tradeoffs th...

Underwater robotics projects offer an excellent medium for discovery based engineering and science learning. The challenge of building underwater robotic vehicles and manipulators engages and stimulates students while encompassing a very broad spectrum of engineering disciplines and scientific concepts. This paper describes the successful design and implementation of student projects, building wire guided remotely operated underwater vehicles (ROVs) with motorized grabbers. This work is part of an ongoing effort to incorporate innovative, hands on projects into our freshman engineering curriculum. These projects help expose students to practical design issues in the freshman year, foster creative problem solving skills and may aid student retention on engineering programs. These projects have also been successfully piloted in pre-college programs, aimed at generating interest in engineering careers among high school students.

We are developing two classes of biomimetic autonomous underwater vehicles based on animal models with superior performance in shallow water. The first is an 8-legged ambulatory vehicle, that is based on the lobster and is intended for autonomous mine countermeasure operations in rivers, harbors and/or the littoral zone ocean bottom with robust adaptations to irregular bottom contours, current and surge. The second vehicle is an undulatory system that is based on the lamprey and is intended for remote sensing operations in the water column with robust depth/altitude control and high maneuverability. These vehicles are based on a common biomimetic control, actuator and sensor architecture that features highly modularized components and low cost per vehicle. Operating in concert, they can conduct autonomous investigation of both the bottom and water column of the littoral zone or rivers. These biomimetic systems represent a new class of autonomous underwater vehicles that may be adapted to operations in a variety of habitats.

An increasing demand to explore the vast ocean floor for various purposes has made it necessary to deploy networks of underwater unmanned vehicles (UUVs) capable of carrying out multiple tasks. For information transfer among these vehicles, it is essential to design efficient communication systems and techniques which reduce the transmission error thereby improving system performance. The network consists of underwater components which perform activities such as communicating with each other using sound waves, gathering information and transmitting this information to the surface buoys which forward the data to a receiver onshore or on board some ship. This report studies the use of Carrier Interferometry (CI) spreading codes in underwater networks which use DS-CDMA technique for transmitting data. A network model has been presented and performance of DS-CDMA/CI has been studied for this model through simulations. The performance of this system has also been compared to those networks using Walsh-Hadamard (WH) codes to prove that DS-CDMA/CI is a better transmission scheme as compared to DS-CDMA/WH. Furthermore, multirate transmission in underwater environment has also been explored with the use of DS-CDMA/CI simulations. The results have shown that DS-CDMA/CI is an excellent candidate for future single rate as well as multirate transmission schemes.

Underwater glider is an autonomous underwater vehicle that glides by controlling their buoyancy and attitude using internal actuators. By changing the vehicle's buoyancy intermittently, vertical motion can be achieved. Characteristics of glider motion include upward and downward movement in a saw tooth pattern, turning and gliding in a vertical spiral motion and gliding without using thrusters or propellers. This paper presents the modelling and identification on net buoyancy, depth and pitching angle of an underwater glider system. A ballast tank subsystem is considered appropriate for the identification process since it is the main parameter for the motion control. By selecting the ballast rate as the input, three aspects of the dynamics of a glider can be observed: buoyancy, depth of the glider and pitching angle. The MATLAB System Identification Toolbox TM is used to obtain a mathematical model of the glider ballast-buoyancy, ballast-depth and ballast-pitching angle conditioning system. The best three parametric estimation models are chosen, and the results of the comparison between simulated and estimated outputs are presented. The information obtained from the modelling and identification approaches are used for USM's Underwater Glider Prototype controller design. The information observed during this procedure are utilised for optimisation, stability, reliability and robustness analysis of the underwater glider.

This paper describes the design and implementation of an obstacle detection, obstacle avoidance and anti-collision system using a COTS multi-beam forward looking sonar. The purpose is to equip our in-house built MEREDITH autonomous underwater vehicle the capability to navigate around obstacles that arise in its programmed path. This is important for operating near the littorals, where potential hazards are prevalent. For such a system, the ability to identify unknown obstacles and discards false returns and noise is an important issue and extremely challenging. The crux of the problem is to correctly pick-up potential obstacles from the sonar image. To address this problem, image processing technique is employed to extract potential obstacles from the sonar image. This is follow by the employment of a real-time multi-frame filter to confirm the presence of obstacles. Subsequently, confirmed obstacles are put in a 2D grid map, which serves as a workspace representation for MEREDITH to perform real-time path planning. Simulation studies and sea trials were conducted to verify the implementation.

This paper presents a method for guiding an autonomous underwater vehicle (AUV) during sea bottom inspection missions. The vehicle is equipped with several sensors (optical, sonar, acoustic) and is able to detect and follow a pipeline placed on the sea bottom. Neural networks and geometric reasoning methods are integrated to perform a real-time identification of pipeline borders in a complex underwater environment. Different scenarios characterized by both obstacles and/or artifacts (due to reflections of artificial light sources used by the vehicle to illuminate the scene) have been considered. Results focus on pipeline detection accuracy and on AUV missions in the absence or presence of down stream and/or obstacles.

Hydrodynamic coefficients strongly affect the dynamic performance of an autonomous underwater vehicle. Although these coefficients are generally obtained experimentally such as through the planar-motion-mechanism (PMM) test, the measured values are not completely reliable because of experimental difficulties and errors involved. Another approach by which these coefficients can be obtained is the observer method, in which a model-based estimation algorithm predicts the coefficients. In this paper, the hydrodynamic coefficients are estimated using two nonlinear observers-a sliding mode observer and an extended Kalman filter. Their performances are evaluated by comparing the estimated coefficients obtained from the two observer methods with the values as determined from the PMM test. By using the estimated coefficients, a sliding mode controller is constructed for the diving and steering maneuver. It is demonstrated that the controller with the estimated values maintains the desired depth and path with sufficient accuracy.

This paper describes the development of mathematical model, speed, pitch and yaw autopilot, motion and mission planning algorithms for an unmanned underwater vehicle to operate autonomously. Proposed mathematical model, control model, motion and mission planning algorithms are verified by computer simulation results.

A new approach to the fault-accommodating allocation of thruster forces of an autonomous underwater vehicle (AUV) is investigated in this paper. This paper presents a framework that exploits the excess number of thrusters to accommodate thruster faults during operation. First, a redundancy resolution scheme is presented that considers the presence of an excess number of thrusters along with any thruster

A fuzzy logic based general purpose modular control architecture is presented for underwater vehicle autonomous navigation, control and collision avoidance. Three levels of fuzzy controllers comprising the sensor fusion module, the collision avoidance module and the motion control module are derived and implemented. No assumption is made on the specific underwater vehicle type, on the amount of a priori knowledge of the 3-D undersea environment or on static and dynamic obstacle size and velocity. The derived controllers account for vehicle position accuracy and vertical stability in the presence of ocean currents and constraints imposed by the roll motion. The main advantage of the proposed navigation control architecture is its simplicity, modularity, expandability and applicability to any type of autonomous or semi-autonomous underwater vehicles. Extensive simulation studies are performed on the NPS Phoenix vehicle whose dynamics have been modified to account for roll stability.

... However, when the stack is sealed in the CPU housing, access is limited. ... also a base technology that will be used in future ALJV development in the Underwater Technologies Laboratory at ... collision avoidance system for use on the Tuvaaq vehicle is also underway at the UTL. ...

In the last years, the use of unmanned underwater vehicles in various applications such as monitoring , inspection and surveillance of underwater facilities , has been significantly increased. The mission success depends heavily on the ability to diagnose , isolate and accommodate faults that may occur in the thrusters and sensors of the vehicles during the operation. This paper presents an overview on the methods employed for thruster and sensor fault detection, isolation and accommodation of underwater robotic vehicles.

Many underwater intervention tasks are today performed using manned submersibles or remotely operated vehicles in teleoperation mode. Autonomous underwater vehicles are mostly employed in survey applications. In fact, the low bandwidth and significant time delay inherent in acoustic subsea communications represent a considerable obstacle to remotely operate a manipulation system, making it impossible for remote controllers to react to problems in a timely manner.

This paper presents the design and development of a system controller for our USM Autonomous Underwater Vehicle (USM-AUV). The state space design approach was used because this design approach is most suitable for nonlinear system and multi-input multi-output (MIMO) system set-up. The full state feedback control scheme under the state space design topic has been selected for the controller design. In the initial stage, the controller system was designed using the linearised equation of motion. For the USM-AUV vehicle design, the thruster motor output force was selected as the input with the depth position as the output. Analysis of the designed control system performances has been done via simulation in Matlab control simulation software. A satisfactory performance has been achieved from the designed controller system. Optimal parameters values have also been acquired for optimal performance of our USM-AUV platform.

Three examples of inter-agency cooperation utilizing current generation, individual Autonomous Underwater Vehicles (AUVs) are described consistent with recent recommendations of the U.S. Commission on Ocean Policy. The first steps in transforming individual AUVs into adaptive, networked systems are underway. To realize an affordable and deployable system, a network-class AUV must be designed with cost-size constraints not necessarily applied in developing solo AUVs. Vehicle types are suggested based on function and ocean operating regime: surface layer, interior and bottom layer. Implications for platform, navigation and control subsystems are explored and practical formulations for autonomy and intelligence are postulated for comparing performance and judging behavior. Laws and conventions governing intelligent maritime navigation are reviewed and an autonomous controller with conventional collision avoidance behavior is described. Network-class cost constraints can be achieved through economies of scale. Productivity and efficiency in AUV manufacturing will increase if constructive competition is maintained. Constructive strategies include interface and operating standards. Professional societies and industry trade groups have a leadership role to play in establishing public, open standards.

An effort has been initiated to develop a portable system capable of measuring the magnetic signature of a surface ship. The system will employ a formation of multiple AUVs, each equipped with a magnetometer. The objective is to measure total magnetic field at specified locations relative to the surface ship. In the first step of system development, an Autonomous Underwater Vehicle (AUV) has been equipped with a tri-axial fluxgate magnetometer and used to perform preliminary magnetic field measurements. Measurements of this type will be used to calibrate an individual AUV/magnetometer system. Initial measurements appear to meet necessary measurement requirements on noise floor as the standard deviation of the indicated total magnetic field was observed to be 21nT while the AUV proceeded on a straight, level path. Extended Kalman Filters (EKF) are being developed for on-board AUV navigation and post-processing a best estimate for AUV vehicle position. Navigation experiments were conducted to evaluate AUV navigation and position estimation. In these experiments, an independent high-accuracy topside-track system was used to provide groud-truth for comparison. The average error in the on-board estimated position of the AUV used for navigation was 1.84m. The post processing EKF was designed to use all available sensor data. This EKF had an average position error of 0.74m when compared to the ground-truth. Overall, the AUV was able to navigate to an average distance of 1.95m from its desired waypoint track.

The early stages of design and simulation of a new concept, autonomous underwater vehicle equipped with vectored thrusters is investigated. The opportunity to increase the research effort in innovative solutions for AUV propulsion and guidance systems is related to the state-ofthe-art analysis. The dynamics of submersibles is briefly recalled, to justify the choice to equip the vehicle with a three degrees of freedom mechanism capable to orient both the propeller and the stabilising tail-fins. The vehicle presented has to be considered as a "concept submersible", that needs further improvements and tuning to become a completely running test-bench for navigation system assessment. A tailored simulation package and results are also described, in order to perform a wide ranging numerical test campaign to foresee life cycle behaviour.

Unmanned Underwater Vehicles (UUVs) have gained popularity for the last decades, especially for the purpose of not risking human life in dangerous operations. On the other hand, underwater environment introduces numerous challenges in navigation, control and communi- cation of such vehicles. Certainly, this fact makes the development of these vehicles more interesting and engi- neering-wise more attractive. In this paper,

With recent advances in battery capacity and the development of hydrogen fuel cells, autonomous underwater vehicles (AUVs) are being used to undertake longer missions that were previously performed by manned or tethered vehicles. As a result, more advanced navigation systems are needed to maintain an accurate position over a larger operational area. The accuracy of the navigation system is critical to the quality of the data collected during survey missions and the recovery of the AUV. Many different methods for navigation in different underwater environments have been proposed in the literature. In this paper, the state of the art in navigation technologies for AUVs is investigated for theoretical and operational systems. Their suitability for use in different environments is compared and current limitations of these methods are identified. In addition, new approaches to address these current problems and areas for future research are suggested. Finally, it is concluded that only geophysically referenced methods will enable AUVs to navigate accurately over large areas and that advances in underwater feature recognition are required before these methods can be implemented in operational AUVs.

Mobile robot vision-based navigation has been the source of countless research contributions, from the domains of both vision and control. Vision is becoming more and more common in applications such as localization, automatic map construction, autonomous navigation, path following, inspection, monitoring or risky situation detection. This survey presents those pieces of work, from the nineties until nowadays, which constitute a wide progress in visual navigation techniques for land, aerial and autonomous underwater vehicles. The paper deals with two major approaches: map-based navigation and mapless navigation. Map-based navigation has been in turn subdivided in metric map-based navigation and topological map-based navigation. Our outline to mapless navigation includes reactive techniques based on qualitative characteristics extraction, appearance-based localization, optical flow, features tracking, plane ground detection/tracking, etc... The recent concept of visual sonar has also been revised.

Robotics is a relatively new field of modern technology interested in the design, construction, operation, and use of those machines that replace human labor, especially in cases where it is neither practical nor desirable. These include, by way of example, submarine and terrestrial exploration, satellite recovery and repair, the defusing of explosive devices and work in radioactive environments. In addition, a significant growing application in robotics concerns the use of manipulators in surgical operations.

This work aims to create a standard code for the simulation of the specific underwater manipulator system Orion 7P, using the Robotics Module provided by National Instruments implemented in LabVIEW software.

The benefits of standardization help to reduce the margin of randomness with which each initiative is managed through the introduction of a framework of structured processes. Moreover, it settles and constitutes a base of knowledge and skills shared by all project managers and the project teams, facilitating the communication among them and allowing everyone to contribute or work on the project.

To achieve this goal, we converted a sample standard code for Puma560 to the robotic arm Orion 7P’s application. In the first chapter, we studied the kinematics and the model of Puma560 in order to analyze the sample script and to understand which parts of the code had to be rearranged. In the second chapter, we modeled the Orion 7P arm and re-adapted the Puma560 code. In the third and last chapter, we analyzed the results and considered future possible developments for this project.

Emergency alarms in the joint forces Command Headquarters create panic in the building in the early hours of the day following reports of a border town being heavily bombed by the enemy. Everyone in the command goes back to their respective seats to attend to their duties. Eventually, signals and orders started flowing to the tri-Services units across the country, preparing them for an offensive action.

The paper addresses the general problem of estimating the position of an underwater target carrying an acoustic emitter by measuring the times of arrival (TOAs) of the acoustic signals at a set of surface buoys equipped with submerged hydrophones and GPS receivers. Examples of underwater targets of interest include AUVs (Autonomous Underwater Vehicles) and ROVs (Remotely Operated Vehicles) as well as manned submersibles, divers, and even marine animals. When compared with classical systems, the class of underwater acoustic positioning systems considered in this paper is far more versatile and portable and the costs of operation are greatly reduced. This justifies the increasing interest that such systems have received over the past few years, both from a theoretical and practical standpoint. Research and development in this area have progressed to the point where a commercial product made its appearance in the market: the so-called GIB (GPS Intelligent Buoys). However, much work remains to be done towards the development of operational systems capable of yielding adequate performance in the presence of multi-path effects and acoustic outliers. The paper gives a brief overview of this area of research and discusses theoretical and practical issues that arise in the development and operation of acoustic positioning systems at sea.

SUMMARY A new unified motion planning algorithm for autonomous Underwater Vehicle-Manipulator Systems (UVMS) has been presented in this paper. Commonly, a UVMS consists of two sub-systems, a vehicle and a manipulator, having vastly different dynamic ...

Recognizing the potential of autonomous underwater vehicles for scientific and military applications, in 1997 MIT and the NATO Undersea Research Centre initiated a Joint Research Project (GOATS), for the development of environmentally adaptive robotic technology applicable to mine counter measures (MCM) and rapid environmental assessment (REA) in coastal environments. The August 2001 GOATS Conference marked the end of this 5 years project, but did not mark the end of the work. The Centre initiated in 2002 a new long-term programme to explore and demonstrate the operational benefits and performances of AUV for covert preparation of the battlespace. Recently the work addressed the evaluation of commercial off-the-shelf (COTS) AUV technology for MCM operations in response to terrorist mining of port. The paper summarizes the work performed and refers to the scientific publications derived from the AUV programme at the NATO Undersea Research Centre. #

A Doppler compensation system is presented which is suitable for high-data-rate acoustic communication between rapidly moving platforms such as autonomous underwater vehicles. The proposed approach provides a generic preprocessor to conventional adaptive receiver structures with only a marginal increase in computational load and hardware cost. The preprocessor employs a novel Doppler estimation technique and efficient sample rate conversion to remove Doppler shift induced by platform velocity and acceleration. Performance predicted by simulation is compared to that of sea trials of a prototype communication system in the North Sea. Successful communication is demonstrated at 16 kbit/s with a transmitting platform moving at up to ± 2.6 m/s.

Measurement delays are inherent in position feedback methods used for underwater navigation. Even for small delays, proper treatment of these measurements will provide more robust performance and reduce uncertainties, improving overall precision. The Kalman filter (KF) can be adapted to treat delayed measurements in an efficient and mathematically rigorous way. We present a delayed state sigma point Kalman filter (SPKF) implementation for underwater navigation using delayed position measurements. The implementation includes a novel model-based approach to fusing the delayed measurements, with the ability to handle varying delays. We provide an example mission scenario where a surface tender with an ultra-short baseline (USBL) system tracks a submerged vehicle. We use this example to renavigate field data from recent deployments of the National Deep Submergence Facility (NDSF) autonomous underwater vehicle (AUV) Sentry, and compare estimates from a delay-compensated filter to those from a filter that ignores the delay.

Exploration of remote environments, once the domain of intrepid adventurers, can now be conducted in relative safety using unmanned vehicles. This article describes the joint University of Michigan (UMich) and Michigan Tech Research Institute's project to design and to build a new autonomous surface vessel (ASV) for use in research, education, and resource management as well as in the commercial sector.