Improving a position controller for a robotic joint

There are several industrial processes that are controlled by a PID or similar controller. In robotics it is also usual the need of position control of joints. Tune a controller is the process to obtain the gains that optimise the behaviour of the system while maintaining its stability and robustness. This paper presents an approach of tuning a speed controller using the Internal Model Control (IMC) method and a position controller using the second order Bessel prototype while testing in different controllers methodology, such as PID, Cascade and feedforward combination with dead zone compensation. In order to compare the controllers, results for an Hermite reference position will allow to validate the proposed solution.info:eu-repo/semantics/publishedVersio

New approach for beacons based mobile robot localization using kalman filters

New approaches on industrial mobile robots are changing the localization systems from old methods such as magnetic tapes to laser beacons based systems and natural landmarks since they are more adaptable and easier to install on the shop floor. Sensor fusion methods needs to be applied since there is information provided from different sources. Extended Kalman Filters are very used in the pose estimation of mobile robots with sensors that detect beacons and measure its distance and angle in a local referential frame. In certain situations, like for example wheels slippage, the number of impulses read for the encoders is wrong, resulting in a very large displacement or rotation and causing a bad estimation at the end of the prediction step. This bad estimation is used for the linearization of the non-linear equations, causing a bad linear approximation and probably a failure in the Kalman Filter. In this paper it is demonstrated that if we use the last state estimation calculated in the update step at the last cycle, instead of the estimation from the prediction step in the actual cycle, the result is an estimator much more robust to errors in the odometry information. Simulated and real results from several experiments are illustrated to demonstrate this new approach.This work is co-financed by the ERDF – European Regional Development Fund through the Operational Programme for Competitiveness and Internationalisation - COMPETE 2020 and the Lisboa2020 under the PORTUGAL 2020 Partnership Agreement, and through the Portuguese National Innovation Agency (ANI) as a part of project PRODUTECH SIF: POCI01-0247-FEDER-024541. This work is 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 Portuguese funding agency, FCT - Fundac¸ao para a Ci ˜ encia e a Tecnolo- ˆ gia, within project SAICTPAC/0034/2015- POCI-01-0145- FEDER-016418.info:eu-repo/semantics/publishedVersio

Computer-controlled ion-selective electrode switch

The construction of a microcomputer-controlled electrode switch for use in potentiometric determinations is described. This can be coupled to most of the analytical equipment usually found in laboratories, to enable a setting up of automatic systems capable of performing sequential determinations with several ion-selective electrodes. The assessment of its analytical usage and behaviour are discussed

Processo hierárquico analítico na gestão da conservação de vias urbanas pavimentadas

O objetivo geral deste trabalho é apresentar o estudo de critérios de decisão para um modelo de gestão da conservação de vias urbanas pavimentadas com a aplicação do Processo Hierárquico Analítico (AHP - Analytic Hierarchy Process). O AHP éé utilizado com o objetivo de definir o grau de importância (pesos) dos critérios relevantes ao processo decisório. Com base no Método de Comparação Par a Par, a fase de definição da importância relativa de cada critério contou com um painel de especialistas que preencheram planilhas eletrônicas e atribuíram pesos aos critérios de decisão. No intuito de ampliar as expectativas em relação aos critérios utilizados, a metodologia aplicada trouxe bons resultados, por considerar um grande número de critérios relevantes no que diz respeito ao estudo de prioridades em vias urbanas. O processo AHP permitiu calcular a consistência dos julgamentos efetuados, o que garante um elevado nível de confiabilidade no conjunto de pesos resultantes

A step towards personalized medicine: establishment of a pharmacogenomics profile of response to BCG intravesical immunotherapy in bladder cancer

The most effective adjuvant therapy of non-muscle invasive bladder cancer (NMIBC) during the last 35 years has been the intravesical instillation with Bacillus Calmette-Guerin (BCG). However, despite its efficacy, approximately 30% of the patients present treatment failure and tumor may progress.info:eu-repo/semantics/publishedVersio