Controlo e estimação do posicionamento absoluto de um robot omnidireccional de três rodas

Este artigo aborda o tema Controlo de Robots Omnidireccionais. O robot usado como caso de estudo utiliza motores DC com encoders e possui 3 rodas especiais que permitem a sua omnidireccionalidade. O movimento destes robots não está sujeito às restrições dos robots mais usuais que utilizam apenas duas rodas normais, tendo como desvantagem o seu controlo ser mais complexo. O principal objectivo deste trabalho foi o de desenvolver um controlador que permita o seguimento de trajectórias pré-definidas com velocidade controlada, estimando-se o posicionamento absoluto do robot baseado na odometria. Os problemas de controlo em robótica incluem inevitáveis requisitos de tempo real muito apertados. Nesta situação particular, o cálculo da odometria e do controlo para um robot omnidireccional é computacionalmente muito mais pesado que para os tipicamente usados robots diferenciais. Deste modo é necessário ter um cuidado especial ao implementar as operações matemáticas necessárias pois o código deve ser optimizado com vista a cumprir requisitos de tempo real. Como motivação para a utilização de robots omnidireccionais é apresentada a comparação desta configuração com a mais típica configuração diferencial

Ultra-wideband time of flight based localization system and odometry fusion for a scanning 3 DoF magnetic field autonomous robot

Solving the robot localization problem is one of the most necessary requirements for autonomous robots. Several methodologies can be used to determine its location as accurately as possible. What makes this difficult is the existence of uncertainty in the sensing of the robot. The uncertain information needs to be combined in an optimal way. This paper stresses a Kalman filter to combine information from the odometry and Ultra Wide Band Time of Flight distance modules, which lacks the orientation. The proposed system validated in a real developed platform performs the fusion task which outputs position and orientation of the robot. It is used to localize the robot and make a 3 DoF scanning of magnetic field in a room. Other examples can be pointed out with the same localization techniques in service and industrial autonomous robots.Project “TEC4Growth - Pervasive Intelligence, Enhancers and Proofs of Concept with Industrial Impact/NORTE-01-0145-FEDER-000020” is financed by the North Portugal Regional Operational. Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, and through the European Regional Development Fund (ERDF). This work is also financed by the ERDF European Regional Development Fund through the Operational Programme for Competitiveness and Internationalisation - COMPETE 2020 Programme, and by National Funds through the FCT Funda¸cao para a Ciˆencia e a Tecnologia (Portuguese Foundation for Science and Technology) within project POCI-01-0145-FEDER-006961.info:eu-repo/semantics/publishedVersio

A modular approach to real-time cork classification using image processing

This paper’s main purpose is to present an automatic vision assortment system for cork classification. Cork is a natural material that is used to seal wine bottles for its reliability and for its chemical and mechanic properties. A modular approach isolates the hard real-time sub problems. It includes some custom developed hardware and software. The developed and implemented system acquires images by a linear CCD camera, transmits that image over an Ethernet based network and processes that image to extract quantitative elements. This system can analyse and distinguish defects that one can find on the surface of a cork stopper and it is also possible to adapt the system to other kinds of problems. The size, form and position of the defects are analysed and the stability of repeated measures is observed. This result allows us to validate the presented methodology

Real time cork classification method: a colour image processing approach

This paper presents an automatic vision assortment method for cork classification. Cork is a natural material that is used to seal wine bottles due to its reliability and its chemical and mechanical properties. A colour image acquisition system is able to differentiate some cork defects. The developed and implemented system acquires images using a colour linear CCD camera, transmits that image through a fast acquisition card and processes that image to extract quantitative elements. This system can analyse and distinguish defects present on the surface of a cork stopper: the size, form and position of the defects are analysed

Controlo e estimação do posicionamento absoluto de um robot omnidireccional de três rodas

Este artigo aborda o tema Controlo de Robots Omnidireccionais. O robot usado como caso de estudo utiliza motores DC com encoders e possui 3 rodas especiais que permitem a sua omnidireccionalidade. O movimento destes robots não está sujeito às restrições dos robots mais usuais que utilizam apenas duas rodas normais, tendo como desvantagem o seu controlo ser mais complexo. O principal objectivo deste trabalho foi o de desenvolver um controlador que permita o seguimento de trajectórias pré-definidas com velocidade controlada, estimando-se o posicionamento absoluto do robot baseado na odometria. Os problemas de controlo em robótica incluem inevitáveis requisitos de tempo real muito apertados. Nesta situação particular, o cálculo da odometria e do controlo para um robot omnidireccional é computacionalmente muito mais pesado que para os tipicamente usados robots diferenciais. Deste modo é necessário ter um cuidado especial ao implementar as operações matemáticas necessárias pois o código deve ser optimizado com vista a cumprir requisitos de tempo real. Como motivação para a utilização de robots omnidireccionais é apresentada a comparação desta configuração com a mais típica configuração diferencial

Pequenos RNAs não codificantes em bactérias do complexo Burkholderia cepacia: contribuição para a sua identificação e caracterização do seu papel na virulência

Tese de mestrado. Biologia (Biologia Humana e Ambiente). Universidade de Lisboa, Faculdade de Ciências, 2011Nos últimos anos, um número crescente de trabalhos tem evidenciado que os pequenos RNAs reguladores não-codificantes (sRNAs) desempenham um papel basilar na regulação da expressão pós-transcricional de vários genes em procariontes. Entre esses genes, assumem particular importância aqueles cujos produtos constituem factores de virulência e de resposta a stresses vários. Os sRNAs permanecem praticamente desconhecidos no Complexo Burkholderia cepacia (Bcc). O Bcc compreende pelo menos dezassete espécies patogénicas oportunistas geneticamente próximas, capazes de causar infecções, particularmente graves em doentes com fibrose quística, em doentes imunocomprometidos e em doentes hospitalizados. O uso do nemátodo Caenorhabditis elegans como modelo de infecção permitiu identificar um mutante de B. cepacia IST408 cuja virulência foi severamente reduzida, devido à interrupção dum gene codificante para uma proteína 84% similar à chaperona de pequenos RNAs de Escherichia coli, a proteína Hfq. A conhecida interacção entre a proteína do Hfq2 e sRNAs potencia o interesse do uso desta proteína como ferramenta para o isolamento de sRNAs através de técnicas de co-purificação. Neste contexto, o presente trabalho contribuiu para a identificação e caracterização do papel de um sRNA, denominado mtvR, envolvido na virulência de Burkholderia cenocepacia J2315.Over the last years, increasing evidence has shown that small noncoding regulatory RNAs (sRNAs) play a critical role in the post-transcriptional regulation of gene expression in prokaryotes. Among genes recognized to be subject to post-transcriptional regulation, particular attention has been given to those encoding determinants of virulence and resistance to various stresses. The roles played by sRNAs remain unknown in bacteria of the Burkholderia cepacia complex (Bcc). The Bcc includes opportunistic pathogens that belong to at least seventeen closely related species, able to cause severe and often lethal infections, particularly among cystic fibrosis patients, immunocompromised patients and hospitalized patients. Previous work from the IST research team led to the identification of a gene encoding a protein 84% similar to the Escherichia coli RNA chaperone Hfq. In the present work we have exploited the known interaction between Hfq2 and sRNAs in co-purification experiments, envisaging the identification of sRNAs from Bcc. In this context, this program contributed to the identification and characterization of the sRNA mtvR. This sRNA plays a role in the virulence of Burkholderia cenocepacia J2315, as demonstrated by experiments using the nematode Caenorhabditis elegans as an infection model

Sensor and actuator stochastic modeling of the Lego mindstorms NXT educational kit

This paper describes the sensor and actuator stochastic modeling of Lego Mindstorms NXT educational kit. It will be also presented the experimental setups applied to obtain each sensor and actuator parameters. The introduction of an industrial robot in some of the experimental setups allowed to increase the speed, repeatability and to reduce errors in the process of sensor data collecting

Code migration from a realistic simulator to a real wheeled mobile robot

This paper describes the code migration from a realistic simulator to a real wheeled mobile robot. The robot software consists in the localization and navigation of an omnidirectional robot in a structured environment. The localization estimate is achieved by fusing odometry and infra-red distance sensors data, applying an extended Kalman filter

Part alignment identification and adaptive pick-andplace operation for flat surfaces

Industrial laser cutting machines use a type of support base that sometimes causes the cut metal parts to tilt or fall, which hinders the robot from picking the parts after cutting. The objective of this work is to calculate the 3D orientation of these metal parts with relation to the main metal sheet to successfully perform the subsequent robotic pick-and-place operation. For the perception part the system relies on the low cost 3D sensing Microsoft Kinect, which is responsible for mapping the environment. The previously known part positions are mapped in the new environment and then a plane fitting algorithm is applied to obtain its 3D orientation. The implemented algorithm is able to detect if the piece has fallen or not. If not, the algorithm calculates the orientation of each piece separately. This information is later used for the robot manipulator to perform the pick-and-place operation with the correct tool orientation. This makes it possible to automate a manufacturing process that is entirely human dependent nowadays.The work presented in this paper, being part of the Project PRODUTECH PTI (nº13851) – New Processes and Innovative Technologies for the Production Technologies Industry, has been partly funded by the Incentive System for Technology Research and Development in Companies (SI I&DT), under the Competitive Factors Thematic Operational Programme, of the Portuguese National Strategic Reference Framework, and EU's European Regional Development Fund". The authors also thanks the FCT (Fundação para a Ciência e Tecnologia) for supporting this work trough the project PTDC/EME-CRO/114595/2009 - High-Level programming for industrial robotic cells: capturing human body motion

Real-time tracking of an omnidirectional robot: an extended Kalman filter approach

This paper describes a robust localization system, similar to the used by the teams participating in the Robocup Small size league (SSL). The system, developed in Object Pascal, allows real time localization and control of an autonomous omnidirectional mobile robot. The localization algorithm is done resorting to odometry and global vision data fusion, applying an extended Kalman filter, being this method a standard approach for reducing the error in a least squares sense, using measurements from different sources