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Publicações

Publicações por CRIIS

2021

Machine Learning Optimization for Robotic Welding Parametrization

Autores
Couto, T; Costa, P; Malaca, P; Tavares, P;

Publicação
2021 IEEE INTERNATIONAL CONFERENCE ON AUTONOMOUS ROBOT SYSTEMS AND COMPETITIONS (ICARSC)

Abstract
Welding physics is complex, and therefore the welding parametrization is time-consuming. In manual welding, the "hand", the experience, and the best sensor of all (the eyes) can compensate for the difficulties in finding the right settings (welding parameters, robot posture, speed,...) for a specific weld seam. In robotic welding the robotic arm and the sensors are limited, and the parametrization time escalates. This work aims to develop a flexible welding robotized system, through the introduction of (knowledge-based) decision support for welding parametrization in an advanced robotic work cell, in combination with advanced (collision-free) offline programming and advanced sensing. By selecting a specific application area, structural steel, this work will reduce the degree of complexity during the development, paving the way for the introduction of knowledge-based welding in the robotic arc welding sector.

2021

Prototyping and control of a conveyor belt: An educational experiment in mechatronics

Autores
Gonçalves, J; Ribeiro, J; Costa, P;

Publicação
Lecture Notes in Electrical Engineering

Abstract
In this paper it is presented an educational experiment, that consists of a mechatronic system applied to demonstrate concepts such as prototyping and control. The described mechatronic system is based on a conveyor belt, that was integrated with a manipulator, being physical devices commonly used in the industry. The conveyor Belt was prototyped from scratch, using 3d print technology. Its movement is based on the closed loop control of a DC Motor, based on a PID. The Conveyor Belt was integrated with a Braccio Manipulator from Arduino, using the ZMQ communication library, which is a high-performance asynchronous messaging library. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021.

2021

Welding process automation of aluminum alloys for the transport industry: An industrial robotics approach

Autores
Ribeiro, J; Gonçalves, J; Mineiro, N;

Publicação
Lecture Notes in Electrical Engineering

Abstract
The materials used in the transport industry have been changing in the last decades. The traditional and heavy steel have been switching by the light alloys like aluminum alloys. However, despite their advantages as low density and high corrosion resistance, the manufacturing process, especially fusion welding, is very demanding and challenging. In the transport industry, most of the hyperstatic components made in aluminum alloys are welded manually with the associate financial costs as well as the lack of quality and repeatability. For these reasons, it is urgent to develop new methodologies to automate this process. The present work intends to show a scientific method to automate the welding process of hyperstatic frames, very common in bicycles, made in aluminum alloy. This methodology involves two steps, the first one in which is performed numerical simulations to determine the optimal welding parameters to minimize the distortion and residual stresses. The second step is experimental one, and it is created an automated welding cell with a robot to weld the frames. It has been proved that it is possible to obtain welding aluminum frames with acceptable quality in agreement with the ASME IX standard. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021.

2021

Cdm controller design of a grid connected photovoltaic system

Autores
Coelho, JP; Giernacki, W; Gonçalves, J; Boaventura Cunha, J;

Publicação
Lecture Notes in Electrical Engineering

Abstract
Distributed power sources will become increasingly ubiquitous in the near future. In this power production paradigm, photovoltaic conversion systems will play a fundamental role due to the growing tendency of energy price, and an opposed trend for the photovoltaic panels. This will lead to increased pressure for the installation of this particular renewable energy source in home buildings. In particular, on-grid photovoltaic systems where the generated power can be injected directly to the main power grid. This strategy requires the use of DC-AC inverters whose output is synchronized, in phase, with the main grid voltage. In order to provide steady output in the presence of load disturbances, the inverter must work in closed-loop. This work presents a new way to design an inverter controller by resorting to the CDM design technique. The obtained results suggest that the controller achieved with this method, although simpler than other methods, leads to an acceptable and robust closed-loop response. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021.

2021

CONTROLO 2020

Autores
Gonçalves, JA; Braz-César, M; Coelho, JP;

Publicação
Lecture Notes in Electrical Engineering

Abstract

2021

Experimental and numerical study to minimize the residual stresses in welding of 6082-T6 aluminum alloy

Autores
Costa, S; Souza, MS; Cesar, MB; Goncalves, J; Ribeiro, JE;

Publicação
AIMS MATERIALS SCIENCE

Abstract
One of the most important negative consequence in the fusion welding processes is the generation of tensile residual stresses in welded joints. The main goals of this work are to determine the optimal combination of welding parameters to minimize the residual stress level and the influence of each welding parameter in that feature to weld 6082-T6 aluminum alloy plates using the GMAW welding process. To achieve these goals was implemented the Taguchi orthogonal array (L27) to define the design of numerical and experimental tests. All combinations were simulated in the Simufactwelding 6.0 software, from which it was possible to obtain the values of maximum residual stresses. The data treatment was carried out, reaching the combination of levels for each parameter. With ANOVA analysis was found that the parameter with the greatest influence in the residual stress generation was the welding speed, while the parameter with the least influence was the torch angle. Also, to minimize the residual stresses it was observed that the optimal combination of welding parameters is welding current intensity of 202 A, welding speed of 10 mm/s, and 30 degrees of inclination of the angular torch. The two simulations that resulted in the highest and lowest residual stresses were validated experimentally by the hole drilling method to measure the residual stresses.

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