An approach to vision-based station keeping for an unmanned underwater vehicle

This paper presents an automatic vision-based system for UUV station keeping. The vehicle is equipped with a down-looking camera, which provides images of the sea-floor. The station keeping system is based on a feature-based motion detection algorithm, which exploits standard correlation and explicit textural analysis to solve the correspondence problem. A visual map of the area surveyed by the vehicle is constructed to increase the flexibility of the system, allowing the vehicle to position itself when it has lost the reference image. The testing platform is the URIS underwater vehicle. Experimental results demonstrating the behavior of the system on a real environment are presented

A system to evaluate the accuracy of a visual mosaicking methodology

When underwater vehicles navigate close to the ocean floor, computer vision techniques can be applied to obtain motion estimates. A complete system to create visual mosaics of the seabed is described in this paper. Unfortunately, the accuracy of the constructed mosaic is difficult to evaluate. The use of a laboratory setup to obtain an accurate error measurement is proposed. The system consists on a robot arm carrying a downward looking camera. A pattern formed by a white background and a matrix of black dots uniformly distributed along the surveyed scene is used to find the exact image registration parameters. When the robot executes a trajectory (simulating the motion of a submersible), an image sequence is acquired by the camera. The estimated motion computed from the encoders of the robot is refined by detecting, to subpixel accuracy, the black dots of the image sequence, and computing the 2D projective transform which relates two consecutive images. The pattern is then substituted by a poster of the sea floor and the trajectory is executed again, acquiring the image sequence used to test the accuracy of the mosaicking system

Estimating the motion of an underwater robot from a monocular image sequence

When underwater vehicles perform navigation close to the ocean floor, computer vision techniques can be applied to obtain quite accurate motion estimates. The most crucial step in the vision-based estimation of the vehicle motion consists on detecting matchings between image pairs. Here we propose the extensive use of texture analysis as a tool to ameliorate the correspondence problem in underwater images. Once a robust set of correspondences has been found, the three-dimensional motion of the vehicle can be computed with respect to the bed of the sea. Finally, motion estimates allow the construction of a map that could aid to the navigation of the robot

Towards a real-time vision-based navigation system for a small-class UUV

This paper deals with the problem of navigation for an unmanned underwater vehicle (UUV) through image mosaicking. It represents a first step towards a real-time vision-based navigation system for a small-class low-cost UUV. We propose a navigation system composed by: (i) an image mosaicking module which provides velocity estimates; and (ii) an extended Kalman filter based on the hydrodynamic equation of motion, previously identified for this particular UUV. The obtained system is able to estimate the position and velocity of the robot. Moreover, it is able to deal with visual occlusions that usually appear when the sea bottom does not have enough visual features to solve the correspondence problem in a certain area of the trajectory

Proposal of a parallel architecture for a motion detection algorithm

This paper proposes a parallel architecture for estimation of the motion of an underwater robot. It is well known that image processing requires a huge amount of computation, mainly at low-level processing where the algorithms are dealing with a great number of data. In a motion estimation algorithm, correspondences between two images have to be solved at the low level. In the underwater imaging, normalised correlation can be a solution in the presence of non-uniform illumination. Due to its regular processing scheme, parallel implementation of the correspondence problem can be an adequate approach to reduce the computation time. Taking into consideration the complexity of the normalised correlation criteria, a new approach using parallel organisation of every processor from the architecture is proposed

A review of sensor fusion techniques for underwater vehicle navigation

This work provides a general description of the multi sensor data fusion concept, along with a new classification of currently used sensor fusion techniques for unmanned underwater vehicles (UUV). Unlike previous proposals that focus the classification on the sensors involved in the fusion, we propose a synthetic approach that is focused on the techniques involved in the fusion and their applications in UUV navigation. We believe that our approach is better oriented towards the development of sensor fusion systems, since a sensor fusion architecture should be first of all focused on its goals and then on the fused sensors

An overview of the advantages and constraints of coded pattern projection techniques for autonomous navigation

The absolute necessity of obtaining 3D information of structured and unknown environments in autonomous navigation reduce considerably the set of sensors that can be used. The necessity to know, at each time, the position of the mobile robot with respect to the scene is indispensable. Furthermore, this information must be obtained in the least computing time. Stereo vision is an attractive and widely used method, but, it is rather limited to make fast 3D surface maps, due to the correspondence problem. The spatial and temporal correspondence among images can be alleviated using a method based on structured light. This relationship can be directly found codifying the projected light; then each imaged region of the projected pattern carries the needed information to solve the correspondence problem. We present the most significant techniques, used in recent years, concerning the coded structured light method

Integració i estudi d’un conjunt de propulsors per un robot submarí

L’objectiu d’aquest projecte/treball fi de carrera es estudiar els propulsors i el seu protocol de comunicació proporcionant informació útil a l’hora de dissenyar i construir el robot subaquàtic que implementi els propulsors

Estudi del model dinàmic d’un robot submarí d’intervenció (IAUV) composat per un vehicle i un braç manipulador

Fins a la data d’avui, el grup VICOROB de la Universitat de Girona ha desenvolupat diversos vehicles autònoms (GARBÍ, URIS i ICTINEU). El projecte que comença aquest any té com objectiu desenvolupar un nou vehicle submarí autònom amb capacitat d’intervenció (I-AUV) gràcies a un braç manipulador. Aquest projecte final de carrera té com objectiu desenvolupar en entorn MATLAB un simulador d’un I-AUV, format per un AUV i un braç manipulador de n graus de llibertat per tal d’avaluar les reaccions dels moviments del braç, amb càrrega i sense, sobre el robot, iviceversa

Conception mécanique d'un chien robot : GIPO

La conceció de GIPO té com a areferència el gos AIBO, desenvolupat per Sony. L'estudi per a la seva realització comprèn el desenvolupament de la part tecnològica. S'assumeix que la cinemàtica d'AIBO ha estat àmpliament provada i que és òptima.

Aplicació de gestió de rutes d'operari i incidències d'instal·lacions sobre PDA amb sincronització remota

Una empresa destinada al sector de la informàtica vol crear un nou producte basat en PDA (Personal Digital Assistant), per tal d’oferir noves prestacions als clients actuals, així com poder ampliar la cartera de clients. El producte està destinat a clients de servei tècnic d’instal·lacions (gas, llum, aigua...), els quals tenen diferents tècnics que, basant-se en una ruta establerta, realitzen tasques de manteniment i reparació de les diferents instal·lacions dels clients. Utilitzant la tecnologia .NET amb l’entorn de desenvolupament Visual Studio 2005 i base de dades SQL Server 2005, s’ha creat una aplicació per a PDA que permeti la informatització de tots els processos de gestió de rutes per part dels tècnics

Módulo de modelado hardware GISCMO

Este proyecto tiene como objetivo desarrollar un aplicativo en formato web capaz de dar soporte al modelado de equipos hardware para su posterior publicación en librerías. El proyecto se incluye en un entorno de trabajo constituido por una serie de herramientas de las que nuestro proyecto es una pequeña pero importante parte. Nuestro objetivo comprenderá la creación y posterior gestión de modelos de equipos hardware para ser utilizados por los proyectistas de instalaciones de control industrial, que generen sus trabajos mediante el uso del entorno de desarrollo GISCMO (Gestor integrado de sistemas de control y modelado de objetos).

Controladores PI con acción de reset

El control automàtic exerceix un paper important en molts processos de la industria. Cada un dels sistemes de control requereix d’un controlador, la majoria dels quals són del tipus PI. L’objectiu d’aquest projecte es investigar tècniques que permetin superar les limitacions que tenen els controladors PI lineals. En la resposta d’un sistema de control es poden distingir dues tasques diferents: El seguiment a un canvi d’entrada o consigna correspon a la tasca de servo, mentre que el rebuig a pertorbacions correspon a la tasca de regulatori. Al típic esquema de control realimentat, aquestes dues tasques estan enfrontades, és a dir, una millora a la tasca de servo implica un empitjorament a la tasca de regulatori i a l’inversa. Això suposa un problema al rendiment del sistema, així com la necessitat d’establir un cert compromís entre les dues tasques. El que es pretén en aquest projecte es implementar senzilles regles de control no lineal amb la finalitat de millorar el rendiment del sistema i evitar la necessitat d’establir un compromís entre les dues tasques. Així, es pretén superar les limitacions que aquest té, obtenint controladors PI alternatius fàcilment sintetitzables.

Aplicación web para gestión de incidencias en un departamento de informática

Prototipo aplicación web para trabajo colaborativo que sirve para la gestión de incidencias en un departamento de informática, con gestión de usuarios, grupos de usuarios, incidencias y base de datos de conocimiento.

Underwater SLAM in a marina environment

This paper describes a navigation system for autonomous underwater vehicles (AUVs) in partially structured environments, such as dams, harbors, marinas or marine platforms. A mechanical scanning imaging sonar is used to obtain information about the location of planar structures present in such environments. A modified version of the Hough transform has been developed to extract line features, together with their uncertainty, from the continuous sonar dataflow. The information obtained is incorporated into a feature-based SLAM algorithm running an Extended Kalman Filter (EKF). Simultaneously, the AUV's position estimate is provided to the feature extraction algorithm to correct the distortions that the vehicle motion produces in the acoustic images. Experiments carried out in a marina located in the Costa Brava (Spain) with the Ictineu AUV show the viability of the proposed approach