Vision-based localization of an underwater robot in a structured environment

This paper presents a vision-based localization approach for an underwater robot in a structured environment. The system is based on a coded pattern placed on the bottom of a water tank and an onboard down looking camera. Main features are, absolute and map-based localization, landmark detection and tracking, and real-time computation (12.5 Hz). The proposed system provides three-dimensional position and orientation of the vehicle along with its velocity. Accuracy of the drift-free estimates is very high, allowing them to be used as feedback measures of a velocity-based low-level controller. The paper details the localization algorithm, by showing some graphical results, and the accuracy of the system

Dam wall detection and tracking using a Mechanically Scanned Imaging Sonar

In dam inspection tasks, an underwater robot has to grab images while surveying the wall meanwhile maintaining a certain distance and relative orientation. This paper proposes the use of an MSIS (mechanically scanned imaging sonar) for relative positioning of a robot with respect to the wall. An imaging sonar gathers polar image scans from which depth images (range & bearing) are generated. Depth scans are first processed to extract a line corresponding to the wall (with the Hough transform), which is then tracked by means of an EKF (Extended Kalman Filter) using a static motion model and an implicit measurement equation associating the sensed points to the candidate line. The line estimate is referenced to the robot fixed frame and represented in polar coordinates (rho&thetas) which directly corresponds to the actual distance and relative orientation of the robot with respect to the wall. The proposed system has been tested in simulation as well as in water tank conditions

WMR navigation using local potential field corridors and narrow local occupancy grid perception

Path planning and control strategies applied to autonomous mobile robots should fulfil safety rules as well as achieve final goals. Trajectory planning applications should be fast and flexible to allow real time implementations as well as environment interactions. The methodology presented uses the on robot information as the meaningful data necessary to plan a narrow passage by using a corridor based on attraction potential fields that approaches the mobile robot to the final desired configuration. It employs local and dense occupancy grid perception to avoid collisions. The key goals of this research project are computational simplicity as well as the possibility of integrating this method with other methods reported by the research community. Another important aspect of this work consist in testing the proposed method by using a mobile robot with a perception system composed of a monocular camera and odometers placed on the two wheels of the differential driven motion system. Hence, visual data are used as a local horizon of perception in which trajectories without collisions are computed by satisfying final goal approaches and safety criteria

Local WMR navigation with monocular data

This article presents recent WMR (wheeled mobile robot) navigation experiences using local perception knowledge provided by monocular and odometer systems. A local narrow perception horizon is used to plan safety trajectories towards the objective. Therefore, monocular data are proposed as a way to obtain real time local information by building two dimensional occupancy grids through a time integration of the frames. The path planning is accomplished by using attraction potential fields, while the trajectory tracking is performed by using model predictive control techniques. The results are faced to indoor situations by using the lab available platform consisting in a differential driven mobile robot

Programació del robot e-puck amb Microsoft Robotics Studio

Microsoft Robotics Studio (MRS) és un entorn per a crear aplicacions per a robots utilitzant una gran varietat de plataformes hardware. Conté un entorn de simulació en el que es pot modelar i simular el moviment del robot. Permet també programar el robot, i executar-lo en l’entorn simulat o bé en el real. MRS resol la comunicació entre elsdiferents processos asíncrons que solen estar presents en el software de control d’unrobot: processos per atendre sensors, actuadors, sistemes de control, comunicacions amb l’exterior,... MRS es pot utilitzar per modelar nous robots utilitzant components que ja estiguin disponibles en les seves llibreries, o també permet crear component nous. Per tal de conèixer en detall aquesta eina, seria interessant utilitzar-la per programa els robots e-pucks, uns robots mòbils autònoms de petites dimensions que disposen de dos motors i un complet conjunt de sensors. El que es vol és simular-los, realitzar un programa de control, realitzar la interfície amb el robot i comprovar el funcionament amb el robot real

Sistema de manteniment de l'equilibri per a un robot bípede

Dins el departament d’Electrònica, Informàtica i Automàtica de la Universitat de Girona s’handissenyat i construït dues plataformes bípedes per a l’ús docent. La mésevolucionada d’elles, finalitzada l’any 1999, està composada per dues cames d’alumini ambtres actuadors lineals cada una, simulant la funció del turmell, del genoll i del maluc. Els objectius que es pretenen aconseguir amb aquest projecte són molt concrets i tots ellsestan destinats a millorar el funcionament del robot bípede. Aquests objectius són: (1)dissenyar dos graus de llibertat lineals en forma de pla XY per moure el pes que convinguiper assegurar l’equilibri durant el moviment de la plataforma bípede, (2) dissenyar una placaamb una FPGA que generi senyals PWM pels vuit motors disponibles, que llegeixi els dosencoders dels motors del pla XY i que es comuniqui amb un PC equipat amb una tarjad’adquisició de dades específica, (3) dissenyar una placa de potència adequada pel controldels motors, (4) finalment realitzar un programa per comprovar el correcte funcionament deles plaques, dels actuadors i dels sensors utilitzats en la plataforma bípede

Calcium imaging of odor-evoked responses in the Drosophila antennal lobe.

The antennal lobe is the primary olfactory center in the insect brain and represents the anatomical and functional equivalent of the vertebrate olfactory bulb. Olfactory information in the external world is transmitted to the antennal lobe by olfactory sensory neurons (OSNs), which segregate to distinct regions of neuropil called glomeruli according to the specific olfactory receptor they express. Here, OSN axons synapse with both local interneurons (LNs), whose processes can innervate many different glomeruli, and projection neurons (PNs), which convey olfactory information to higher olfactory brain regions. Optical imaging of the activity of OSNs, LNs and PNs in the antennal lobe - traditionally using synthetic calcium indicators (e.g. calcium green, FURA-2) or voltage-sensitive dyes (e.g. RH414) - has long been an important technique to understand how olfactory stimuli are represented as spatial and temporal patterns of glomerular activity in many species of insects. Development of genetically-encoded neural activity reporters, such as the fluorescent calcium indicators G-CaMP and Cameleon, the bioluminescent calcium indicator GFP-aequorin, or a reporter of synaptic transmission, synapto-pHluorin has made the olfactory system of the fruitfly, Drosophila melanogaster, particularly accessible to neurophysiological imaging, complementing its comprehensively-described molecular, electrophysiological and neuroanatomical properties. These reporters can be selectively expressed via binary transcriptional control systems (e.g. GAL4/UAS, LexA/LexAop, Q system) in defined populations of neurons within the olfactory circuitry to dissect with high spatial and temporal resolution how odor-evoked neural activity is represented, modulated and transformed. Here we describe the preparation and analysis methods to measure odor-evoked responses in the Drosophila antennal lobe using G-CaMP. The animal preparation is minimally invasive and can be adapted to imaging using wide-field fluorescence, confocal and two-photon microscopes.

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.

SLAM using an Imaging Sonar for Partially Structured Underwater Environments

In this paper we describe a system for underwater navigation with AUVs in partially structured environments, such as dams, ports or marine platforms. An imaging sonar is used to obtain information about the location of planar structures present in such environments. This information is incorporated into a feature-based SLAM algorithm in a two step process: (I) the full 360deg sonar scan is undistorted (to compensate for vehicle motion), thresholded and segmented to determine which measurements correspond to planar environment features and which should be ignored; and (2) SLAM proceeds once the data association is obtained: both the vehicle motion and the measurements whose correct association has been previously determined are incorporated in the SLAM algorithm. This two step delayed SLAM process allows to robustly determine the feature and vehicle locations in the presence of large amounts of spurious or unrelated measurements that might correspond to boats, rocks, etc. Preliminary experiments show the viability of the proposed approach

Using petri nets to specify and execute missions for autonomous underwater vehicles

This paper presents the design and implementation of a mission control system (MCS) for an autonomous underwater vehicle (AUV) based on Petri nets. In the proposed approach the Petri nets are used to specify as well as to execute the desired autonomous vehicle mission. The mission is easily described using an imperative programming language called mission control language (MCL) that formally describes the mission execution thread. A mission control language compiler (MCL-C) able to automatically translate the MCL into a Petri net is described and a real-time Petri net player that allows to execute the resulting Petri net onboard an AUV are also presented

Disseny i implementació d'un sistema de navegació inercial i la seva aplicació a la robòtica mòbil

La UdG desposa de diversos robots mòbils per a finalitats docents i de recerca que utilitzen sistemes de localització incremental mitjançant bàsicament encoders incrementals. Actualment, en el mercat de l’automoció s’ha desenvolupat una sèrie de dispositius electrònics tals com brúixoles electròniques, acceleròmetres, giroscòpics, etc. L’objectiu és dissenyar i construir un sistema de navegació inercial format per un acceleròmetre, un giroscòpic, una brúixola i un microcontrolador encarregat de governar les ordres. El llenguatge utilitzat serà l’assemblador, ja que es pretén una execució molt eficient de les rutines creades. Les dades obtingudes es transmetran a l’ordinador per mitjà del protocol RS-232 i un programa en C emmagatzemarà les dades en un document de text. Aquestes dades seran tractades amb l’entorn MATLAB per tal d’interpretar-les i representar-les gràficament. Per analitzar el funcionament del sistema s’utilitzarà la plataforma PRIM

Sistemas heterogéneos adaptativos basados en el contexto

Delivery context-aware adaptative heterogenous systems. Currently, many types of devices that have gained access to the network is large and diverse. The different capabilities and characteristics of them, in addition to the different characteristics and preferences of users, have generated a new goal to overcome: how to adapt the contents taking into account this heterogeneity, known as the “delivery context.” The concepts of adaptation and accessibility have been widely discussed and have resulted in many proposals, standards and techniques designed to solve the problem, making it necessary to refine the analysis of the issue to be considered in the process of adaptation. We present a tour of the various proposals and standards that have marked the area of heterogeneous systems works, and others who have worked since the real-time interaction through agents based platforms. All targeted to solve a common goal: the delivery context

Synthesis of Best Practice for Increasing Protection and Visibility of Highway Maintenance Vehicles, CTRE Final Report Iowa DOT Project TR-475, August 2002

The purpose of this research project is to study current practices in enhancing visibility and protection of highway maintenance vehicles involved in moving operations such as snow removal and shoulder operations, crack sealing, and pothole patching. The results will enable the maintenance staff to adequately assess the applicability and impact of each strategy to their use and budget. The report’s literature review chapter examines the use of maintenance vehicle warning lights, retroreflective tapes, shadow vehicles and truck-mounted attenuators, and advanced vehicle control systems, as well as other practices to improve visibility for both snowplow operators and vehicles. The chapter concludes that the Manual on Uniform Traffic Control Devices does not specify what color or kind of warning lights to use. Thus, a wide variety of lights are being used on maintenance vehicles. The study of the relevant literatures also suggests that there are no clear guidelines for moving work zones at this time. Two types of surveys were conducted to determine current practices to improve visibility and safety in moving work zones across the country and in the state of Iowa. In the first survey of state departments of transportation, most indicated using amber warning lights on their maintenance vehicles. Almost all the responding states indicated using some form of reflective material on their vehicles to make them more visible. Most participating states indicated that the color of their vehicles is orange. Most states indicated using more warning lights on snow removal vehicles than their other maintenance vehicles. All responding state agencies indicated using shadow vehicles and/or truck-mounted attenuators during their moving operations. In the second survey of Iowa counties, most indicated using very similar traffic control and warning devices during their granular road maintenance and snow removal operations. Mounting warning signs and rotating or strobe lights on the rear of maintenance vehicles is common for Iowa counties. The most common warning devices used during the counties’ snow removal operations are reflective tapes, warning flags, strobe lights, and auxiliary headlamps.

Integració d’ una unitat inercial i d’ un giroscopi de fibra òptica en un robot submarí i desenvolupament d’ un sistema de posicionament dins una piscina

El Grup de Visió per Computador i Robòtica (VICOROB) del departament d'Electrònica, Informàtica i Automàtica de la Universitat de Girona investiga en el camp de la robòtica submarina. Al CIRS (Centre d’Investigació en Robòtica Submarina), laboratori que forma part del grup VICOROB, el robot submarí Ictineu és la principal eina utilitzada per a desenvolupar els projectes de recerca. Recentment, el CIRS ha adquirit un nou sistema de sensors d' orientació basat en una unitat inercial i un giroscopi de fibra òptica. Aquest projecte pretén realitzar un estudi d' aquests dispositius i integrar-los al robot Ictineu. D' altra banda, aprofitant les característiques d’aquests sensors giroscopics i les mesures d' un sonar ja integrat al robot, es vol desenvolupar un sistema de localització capaç de determinar la posició del robot en el pla horitzontal de la piscina en temps real

Eina de mobilitat pel sistema de la producció d’Ormetal

L’objectiu principal d’aquest projecte consisteix en realitzar l’estudi, l' anàlisi, el disseny, i el desenvolupament d’una aplicació que millori i faciliti la tasca d’un empleat que treballi fora de l’empresa. Es fa una anàlisi dels requeriments de l’aplicació, es fa el model d’anàlisi i tot seguit el model de disseny, i s’implementarà mitjançant les eines que utilitza la nostra empresa o les que millor s’adaptin a ella. S’analitza també el tipus i el volum d’informació que haurà de manejar. Durant el procés de cada una de les etapes de desenvolupament s’aniran realitzant les corresponents proves per, finalment, realitzar una posada en marxa sobre un empleat a mode de proves en un entorn real. Degut a la necessitat de mobilitat dels comercials s’utilitzen dispositius PDA (Personal Digital Assistant) per al desenvolupament de l’aplicació que els permetrà realitzar les seves tasques. En canvi, l’aplicació corporativa de gestió de l’empresa està situada en un servidor Windows, i per centralitzar i gestionar la informació de les PDA s’utilitzarà una aplicació sota el sistema Windows. L’aplicació s’haurà de confeccionar en funció de les dades que es vulgui que el comercial pugui consultar sobre un client, obra, ... Per millorar-ne la seva funcionalitat, es permetrà l’opció de multi-llenguatge. L’aplicació de la PDA tindrà a grans trets les següents funcionalitats: gestió de clients, gestió de contactes, consultar gestions comercials, consultar obres dels clients, consultar el planning i l’estat dels muntadors. Altres processos que haurà de permetre l’aplicació son: la configuració i instal·lació de l’aplicació en els dispositius PDA i la càrrega i el traspàs de les dades entre l’aplicació del PDA i l’aplicació corporativa de l’empresa