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Publications

Publications by CRIIS

2023

CNC Machines Integration in Smart Factories using OPC UA?

Authors
Martins, A; Lucas, J; Costelha, H; Neves, C;

Publication
JOURNAL OF INDUSTRIAL INFORMATION INTEGRATION

Abstract
This paper examines the idea of Industry 4.0 from the perspective of the molds industry, a vital industry in today's industrial panorama. Several technologies, particularly in the area of machining equipment, have been introduced as a result of the industry's constant modernization. This technological diversity makes automatic interconnection with production management software extremely difficult, as each brand and model requires different, mostly proprietary, interfaces and communication protocols. In the methodology presented in this paper, a development of monitoring solutions for machining devices is defined supporting the leading equipment and operations used by molds industry companies. OPC UA is employed for high-level communication between the various systems for a standardized approach. The approach combines various machine interfaces on a single system to cover a significant subset of machining equipment currently used by the molds industry, as a key result of this paper and given the variety of monitoring systems and communication protocols. This type of all-in-one approach will provide production managers with the information they need to monitor and improve the complete manufacturing process.

2023

Digital Twin Development for a Quality Control Cell

Authors
Cavalcanti, M; Costelha, H; Neves, C; Martins, A; Perdigoto, L;

Publication
9th 2023 International Conference on Control, Decision and Information Technologies, CoDIT 2023

Abstract
The Digital Twin is one of the enabling technologies of Industry 4.0, Cyber-Physical Systems and Smart Factories. In this context, Digital Twins can be developed for being employed through the entire lifecycle of a system, for design, operation, monitoring, maintenance, and even fault prediction and reconfiguration. This paper describes the development of a Digital Twin for a Quality Control cell that is part of a larger manufacturing process in the automotive industry. The virtual environment was built using ABB RobotStudio, the communication between devices in the cell was implemented with OPC UA (UA. NET and open62541), and the process data are registered in a database using MySQL. The results show a fully functional simulation of the cell's behaviour and future development will include the connection of the Digital Twin with the real system. © 2023 IEEE.

2023

Path Generation and Execution for Automatic Shotcrete in Railway Tunnels

Authors
Moniz, G; Costelha, H;

Publication
2023 IEEE INTERNATIONAL CONFERENCE ON AUTONOMOUS ROBOT SYSTEMS AND COMPETITIONS, ICARSC

Abstract
The shotcrete process has been extensively used for many years in different civil and mining operations. Nevertheless, it is still either applied by an operator which controls the shotcrete nozzle manually or through a remote control. In either case, the operation is entirely controlled by the operator. Automating the shotcrete process involves developments in different parts of the process, such as the tunnel scanning for 3D model generation and the shotcrete path automatic generation and execution. This paper describes the work developed for this last part, namely the automatic generation and execution of a shotcrete path, given the mesh of a tunnel and a set of input parameters, for application in railway tunnels. The developed path also considers specificities of the concrete projection process, such as the uncontrolled flow variation due to the pumping systems, generating a trajectory that aims at minimizing this effect. Results are shown using a realistic simulator and an uneven railway tunnel, using an industrial robot mounted on a railway wagon.

2023

Model-Free VRFT-Based Tuning Method for PID Controllers

Authors
Vrancic, D; Oliveira, PM; Bisták, P; Huba, M;

Publication
MATHEMATICS

Abstract
The main objective of this work was to develop a tuning method for PID controllers suitable for use in an industrial environment. Therefore, a computationally simple tuning method is presented based on a simple experiment on the process without requiring any input from the user. Essentially, the method matches the closed-loop response to the response obtained in the steady-state change experiment. The proposed method requires no prior knowledge of the process and, in its basic form, only the measurement of the change in the steady state of the process in the manually or automatically performed experiment is needed, which is not limited to step-like process input signals. The user does not need to provide any prior information about the process or any information about the closed-loop behavior. Although the control loop dynamics is not defined by the user, it is still known in advance because it is implicitly defined by the process open-loop response. Therefore, no exaggerated control signal swings are expected when the reference signal changes, which is an advantage in many industrial plants. The presented method was designed to be computationally undemanding and can be easily implemented on less powerful hardware, such as lower-end PLC controllers. The work has shown that the proposed model-free method is relatively insensitive to process output noise. Another advantage of the proposed tuning method is that it automatically handles the tuning of highly delayed processes, since the method discards the initial process response. The simplicity and efficiency of the tuning method is demonstrated on several process models and on a laboratory thermal system. The method was also compared to a tuning method based on a similar closed-loop criterion. In addition, all necessary Matlab/Octave files for the calculation of the controller parameters are provided online.

2023

Ant-Balanced Multiple Traveling Salesmen: ACO-BmTSP

Authors
Pereira, SD; Pires, EJS; Oliveira, PBD;

Publication
ALGORITHMS

Abstract
A new algorithm based on the ant colony optimization (ACO) method for the multiple traveling salesman problem (mTSP) is presented and defined as ACO-BmTSP. This paper addresses the problem of solving the mTSP while considering several salesmen and keeping both the total travel cost at the minimum and the tours balanced. Eleven different problems with several variants were analyzed to validate the method. The 20 variants considered three to twenty salesmen regarding 11 to 783 cities. The results were compared with best-known solutions (BKSs) in the literature. Computational experiments showed that a total of eight final results were better than those of the BKSs, and the others were quite promising, showing that with few adaptations, it will be possible to obtain better results than those of the BKSs. Although the ACO metaheuristic does not guarantee that the best solution will be found, it is essential in problems with non-deterministic polynomial time complexity resolution or when used as an initial bound solution in an integer programming formulation. Computational experiments on a wide range of benchmark problems within an acceptable time limit showed that compared with four existing algorithms, the proposed algorithm presented better results for several problems than the other algorithms did.

2023

Pocket Labs as a STEM Learning Tool and for Engineering Motivation

Authors
Cardoso, A; Oliveira, PM; Sa, J;

Publication
LEARNING IN THE AGE OF DIGITAL AND GREEN TRANSITION, ICL2022, VOL 1

Abstract
Teaching and learning are processes that must accompany the digital transition, which is one of the biggest challenges we currently face, along with the green transition. The digital transition in education is a process with several challenges that must count on the involvement and collaboration of all stakeholders, contributing to the schools of the future. For this, technology plays a decisive role, and must be integrated into classes as a relevant tool to develop and implement different types of experiments, motivating the students towards STEM areas. In this context, a project financed by IFAC made it possible to use pocket laboratories in different high schools, encouraging teachers to prepare activities supported by this equipment, stimulating students to be interested in engineering topics. This article presents the approach followed in one high school and discusses the results obtained, highlighting the usefulness and opportunity of using pocket labs, and low-cost equipment in general, in school activities, which can promote the STEM areas and, in particular, the engineering courses.

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