Search results for "Underwater vehicle"
showing 10 items of 14 documents
Design of a modular Autonomous Underwater Vehicle for archaeological investigations
2015
MARTA (MARine Tool for Archaeology) is a modular AUV (Autonomous Underwater Vehicle) designed and developed by the University of Florence in the framework of the ARROWS (ARchaeological RObot systems for the World's Seas) FP7 European project. The ARROWS project challenge is to provide the underwater archaeologists with technological tools for cost affordable campaigns: i.e. ARROWS adapts and develops low cost AUV technologies to significantly reduce the cost of archaeological operations, covering the full extent of an archaeological campaign (underwater mapping, diagnosis and cleaning tasks). The tools and methodologies developed within ARROWS comply with the "Annex" of the 2001 UNESCO Conv…
The ARROWS project: adapting and developing robotics technologies for underwater archaeology
2015
4th IFAC Workshop on Navigation, Guidance and Control of Underwater Vehicles, NGCUV 2015; Girona; Spain; 28 April 2015 through 30 April 2015
Low-cost underwater navigation systems by multi-pressure measurements and AHRS data
2017
This paper deals with accurate navigation for underwater remotely operated vehicles. A feasibility study for a multi-pressure device to be mounted on an ROV is presented. The device can provide accurate estimates of a ROV orientation and angular speed. It is based on the well-known total pressure principle, also used in a Pitot tube, and allows reconstruction of static and dynamic pressures, which in turn provide good estimates of the ROV's orientation and rotational speed, respectively. An appealing feature of the proposed device is its ability to provide accurate estimates even for low-speed movements.
VISOCAR: an autonomous industrial transport vehicle guided by visual navigation
2003
The authors describe a vision system, called VISOCAR, for mobile robot guidance in industrial environments. VISOCAR is an optically navigating AGV (automatically guided vehicle) that, owing to its local intelligence, can travel automatically in its natural environment, does not need any dedicated floor installations, and does not impose any restrictions on the route network or factory environment. It can navigate accurately on its track and integrate multisensor information to enhance functional redundancy and system reliability. It is shown that the navigation task can be broken down into a hierarchy of goals, which can be attained by functionally independent modules. The system architectu…
Trajectory tracking of underactuated underwater vehicles
2003
This paper deals with a control strategies for underactuated underwater vehicles whose target is the tracking of a space trajectory. A cascade control strategy is employed which brings to a control law consisting of: 1) a kinematic control law, derived from the vehicle kinematic model, which forces this model to track the reference trajectory; and 2) a dynamic control law which forces the system to track the reference signals given by the kinematic control law. Conditions for asymptotic tracking of the trajectory are given with reference to the standard dynamical model of the above vehicle. An observer of the marine current is also added in order to process the control law. Simulation tests…
Virtual Vehicles Manager: a java virtual reality environment for distributed multi vehicles dynamics control and simulation
2007
This paper describes a lightweight, full portable software environment for development, simulation and control of vehicles. All the software is developed in Java so there are many advantages as portability, multithreading distribution etc. This environment simulates the vehicles integrating their non-linear differential equation systems. The equation systems can easily be modified changing that representation class so it is easy to manage different vehicles. The scenario is displayed as a 3D virtual reality environment in which all the objects are rendered using a combination of 3 d primitive. It is also possible the use of pre-built 3 d objects loaded from files in 3 ds format. The softwar…
Fuzzy/Kalman Hierarchical Horizontal Motion Control of Underactuated ROVs.
2010
A new closed loop fuzzy motion control system including on-line Kalman's filter (KF) for the two dimensional motion of underactuated and underwater Remotely Operated Vehicle (ROV) is presented. Since the sway force is unactuated, new continuous and discrete time models are developed using a polar transformation. A new hierarchical control architecture is developed, where the high level fuzzy guidance controller generates the surge speed and the yaw rate needed to achieve the objective of planar motion, while the low level controller gives the thruster surge force and the yaw torque control signals. The Fuzzy controller ensures robustness with respect to uncertainties due to the marine envi…
UWSim-NET: An Open-Source Framework for Experimentation in Communications for Underwater Robotics
2019
The communication with the remotely operated vehicles (ROV) in underwater applications are usually based on umbilical cables. The increase in the number of ROVs in cooperative interventions motivates the interest in underwater wireless communications. They have a high impact in robotic applications because of their limited performance in underwater scenarios. In this work we present UWSim-NET, an extension of the simulator for underwater robotics UWSim, which is based on the Robot Operating System (ROS). UWSim-NET integrates a communications module based on Network Simulator 3 (NS3) that allows to model the physical and data link layers. Experiments demonstrating the capabilities of UWSim-N…
Space variant vision and pipelined architecture for time to impact computation
2002
Image analysis is one of the most interesting ways for a mobile vehicle to understand its environment. One of the tasks of an autonomous vehicle is to get accurate information of what it has in front, to avoid collision or find a way to a target. This task requires real-time restrictions depending on the vehicle speed and external object movement. The use of normal cameras, with homogeneous (squared) pixel distribution, for real-time image processing, usually requires high performance computing and high image rates. A different approach makes use of a CMOS space-variant camera that yields a high frame rate with low data bandwidth. The camera also performs the log-polar transform, simplifyin…
Piecewise planar underwater mosaicing
2015
A commonly ignored problem in planar mosaics, yet often present in practice, is the selection of a reference homography reprojection frame where to attach the successive image frames of the mosaic. A bad choice for the reference frame can lead to severe distortions in the mosaic and can degenerate in incorrect configurations after some sequential frame concatenations. This problem is accentuated in uncontrolled underwater acquisition setups as those provided by AUVs or ROVs due to both the noisy trajectory of the acquisition vehicle — with roll and pitch shakes — and to the non-flat nature of the seabed which tends to break the planarity assumption implicit in the mosaic construction. These…