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

Psychometric properties of the Comic Style Markers – Portuguese version: applying bifactor and hierarchical approaches to studying broad versus narrow styles of humor

Corresponding Author: Paulo A. S. Moreira, Instituto de Psicologia e de Ciências da Educação [Institute of Psychology and Education], Universidades Lusíada, Porto, Portugal; and Centro de Investigação em Psicologia para o Desenvolvimento (CIPD) [The Psychology for Positive Development Research Centre], Porto, Portugal, E-mail: [email protected]. https://orcid.org/0000-0002-5454-7971Corresponding Author: Richard A. Inman, Centro de Investigação em Psicologia para o Desenvolvimento (CIPD) [The Psychology for Positive Development Research Centre], Porto, Portugal, E-mail: [email protected] the relevance of humor for psychosocial assessment and promoting positive functioning, it is important to understand the relationship between humor and personality. A recent framework for describing individual differences in humor posits eight comic styles that can be measured using the Comic Style Markers (CSM). In total, 665 Portuguese adults (Mage = 32.1 years) completed the CSM and Cloninger’s Temperament and Character Inventory. CFAs supported modeling the CSM as a bifactor model. Bifactor indices suggested a general humor factor could be interpreted as a unidimensional construct, but that CSM items are multidimensional. A hierarchical analysis showed the styles could be represented at several levels of abstraction. A SEM analysis suggested certain styles had distinct associations with personality dimensions. These findings suggest that the use of certain styles (namely wit, sarcasm, and cynicism) was related to individual differences in temperament and character beyond a person’s overall humor potential

Between seeming linearity and hidden immutability: discussing the analysis of social housing policies in Brazil

Housing issue in Brazil has become known for great advances in recent decades, both in the academic and public policies fields. However, despite the undeniable progress, doubts emerge about the effectiveness of the undertaken actions and the role of academic community in overcoming the chronic deficiencies of urban planning in Brazil, which contributes, in ultimate instance, to increase housing deficit. Despite expansions in the knowledge volume produced, there isn't sufficient data in scientific literature to support this panorama with consistency. Thus, we attempt to discuss Brazilian scientific production on housing from a bibliometric study, focusing in the last decade. The results show a detachment of values and ideals adopted in the practice of public management and in academic discourse that, ultimately, leads to questioning the real contribution of academic community in the arduous task of reducing social segregation existing in Brazil.La cuestión de vivienda en Brasil se ha destacado por grandes avances en las últimas décadas, tanto en el campo académico como en la formulación de políticas públicas. Sin embargo, a pesar del indiscutible progreso, surgen dudas sobre la real efectividad de las acciones emprendidas y sobre el papel de la academia en la superación de las deficiencias crónicas de la planificación urbana en Brasil que, en última instancia, conducen al incremento del déficit de vivienda. A despecho de la ampliación del volumen de conocimiento producido, la literatura científica carece de datos que permitan caracterizar este panorama con consistencia. Así, se procura discutir la producción científica brasileña sobre vivienda de interés social a partir de un estudio bibliométrico, con mayor enfoque para la última década. Los resultados obtenidos evidencian una separación de los valores e ideas adoptados en la praxis de la gestión pública y en discurso académico que, en última instancia, conduce al cuestionamiento de la real contribución de los investigadores en la ardua misión de reducir la segregación social existente en Brasil

A adoção do padrão internacional de relatórios financeiros em portugal: podem os custos esperados ser reduzidos?

In this paper we use a cost-benefit framework to discuss some of the expected effects related to the Portuguese adoption of the International Financial Reporting Standards (IFRS). Given the circumstances underlying this implementation, we anticipate that the overall net result following an analysis of costs and benefits will be negative. Therefore, we also examine what seems to be the causal factor behind this outcome and a potential way of reducing the net cost of adopting the IFRS. The costs are related to the professional updating of accounting skills of those directly or indirectly involved in the accounting process. A part of these costs will be incremental and permanent over time mainly due to the fact that two accounting systems will be kept in place. The adoption of a single accounting system, that based on the IFRS, would appear to be a possible solution to reduce such costs

Reutilização de material fresado em camadas estruturais de pavimento : novas perspectivas

Na actualidade, a crescente preocupação com a protecção ambiental, que se verifica em todas as áreas, leva a que, a nível da Engenharia Rodoviária, sejam já utilizadas diversas técnicas de reciclagem de subprodutos resultantes de trabalhos de beneficiação e reforço de pavimentos flexíveis. Neste artigo enquadra-se o processo de reutilização de materiais recorrendo à mistura de material fresado com pó e cimento, dentro dos processos de reciclagem de pavimentos e apresentam-se resultados que permitem concluir que a técnica pode constituir uma alternativa à reutilização de subprodutos da construção, em substituição de camadas granulares de pavimento

Indoor Localization System based on Artificial Landmarks and Monocular Vision

 This paper presents a visual localization approach that is suitable for domestic and industrial environments as it enables accurate, reliable and robust pose estimation. The mobile robot is equipped with a single camera which update sits pose whenever a landmark is available on the field of view. The innovation presented by this research focuses on the artificial landmark system which has the ability to detect the presence of the robot, since both entities communicate with each other using an infrared signal protocol modulated in frequency. Besides this communication capability, each landmark has several high intensity light-emitting diodes (LEDs) that shine only for some instances according to the communication, which makes it possible for the camera shutter and the blinking of the LEDs to synchronize. This synchronization increases the system tolerance concerning changes in brightness in the ambient lights over time, independently of the landmarks location. Therefore, the environment’s ceiling is populated with several landmarks and an Extended Kalman Filter is used to combine the dead-reckoning and landmark information. This increases the flexibility of the system by reducing the number of landmarks required. The experimental evaluation was conducted in a real indoor environment with an autonomous wheelchair prototype

Improving incremental encoder measurement: variable acquisition window and quadrature phase compensation to minimize acquisition errors

Motion control is an important task in several areas, such as robotics where the angular position and speed should be acquired, usually with encoders. For slow angular speeds, an error is introduced spoiling the measurement. In this paper there will be proposed two new methodologies, that when combined allow to increase the precision whereas reducing the error, even on transient velocities. The two methodologies Variable Acquisition Window and a Quadrature Phase Compensation are addressed and combined simultaneously. A real implementation of the proposed algorithms is performed on a real hardware, with a DC motor and a low resolution encoder based on hall effect. The results validate the proposed approach since the errors are reduced compared with the standard Quadrature Encoder Reading.This work has been supported by FCT - Fundac¸ao˜ para a Ciencia e Tecnologia within the Project Scope: ˆ UIDB/05757/2020info:eu-repo/semantics/publishedVersio

Robust mobile robot localization based on a security laser: An industry case study

This paper aims to address a mobile robot localization system that avoids using a dedicated laser scanner, making it possible to reduce implementation costs and the robot's size. The system has enough precision and robustness to meet the requirements of industrial environments. Design/methodology/approach - Using an algorithm for artificial beacon detection combined with a Kalman Filter and an outlier rejection method, it was possible to enhance the precision and robustness of the overall localization system. Findings - Usually, industrial automatic guide vehicles feature two kinds of lasers: one for navigation placed on top of the robot and another for obstacle detection (security lasers). Recently, security lasers extended their output data with obstacle distance (contours) and reflectivity. These new features made it possible to develop a novel localization system based on a security laser. Research limitations/implications - Once the proposed methodology is completely validated, in the future, a scheme for global localization and failure detection should be addressed. Practical implications - This paper presents a comparison between the presented approach and a commercial localization system for industry. The proposed algorithms were tested in an industrial application under realistic working conditions. Social implications - The presented methodology represents a gain in the effective cost of the mobile robot platform, as it discards the need for a dedicated laser for localization purposes. Originality/value - This paper presents a novel approach that benefits from the presence of a security laser on mobile robots (mandatory sensor when considering industrial applications), using it simultaneously with other sensors, not only to guarantee safety conditions during operation but also to locate the robot in the environment. This paper is also valuable because of the comparison made with a commercialized system, as well as the tests conducted in real industrial environments, which prove that the approach presented is suitable for working under these demanding conditions.Project "TEC4Growth" - Pervasive Intelligence, Enhancers and Proofs of Concept with Industrial Impact/NORTE-01-0145-FEDER-000020" is fnanced by the North Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, and through the European Regional Development Fund (ERDF).info:eu-repo/semantics/publishedVersio