2013
Authors
Solteiro Pires, EJ; Lopes, AM; Tenreiro Machado, JA; De Moura Oliveira, PB;
Publication
Robotics: Concepts, Methodologies, Tools, and Applications
Abstract
Most machining tasks require high accuracy and are carried out by dedicated machine-tools. On the other hand, traditional robots are flexible and easy to program, but they are rather inaccurate for certain tasks. Parallel kinematic robots could combine the accuracy and flexibility that are usually needed in machining operations. Achieving this goal requires proper design of the parallel robot. In this chapter, a multi-objective particle swarm optimization algorithm is used to optimize the structure of a parallel robot according to specific criteria. Afterwards, for a chosen optimal structure, the best location of the workpiece with respect to the robot, in a machining robotic cell, is analyzed based on the power consumed by the manipulator during the machining process.
2013
Authors
Carneiro, D; Novais, P; Gomes, M; Oliveira, PM; Neves, J;
Publication
SOFT COMPUTING MODELS IN INDUSTRIAL AND ENVIRONMENTAL APPLICATIONS
Abstract
This paper describes an approach for assessing the level of stress of users of mobile devices with tactile screens by analysing their touch patterns. Two features are extracted from touches: duration and intensity. These features allow to analyse the intensity curve of each touch. We use decision trees (J48) and support vector machines (SMO) to train a stress detection classifier using additional data collected in previous experiments. This data includes the amount of movement, acceleration on the device, cognitive performance, among others. In previous work we have shown the co-relation between these parameters and stress. Both algorithms show around 80% of correctly classified instances. The decision tree can be used to classify, in real time, the touches of the users, serving as an input to the assessment of the stress level.
2017
Authors
Soares, F; Leao, CP; Oliveira, PM;
Publication
2017 25TH MEDITERRANEAN CONFERENCE ON CONTROL AND AUTOMATION (MED)
Abstract
This paper presents some teaching strategies applied in a curricular unit of the 3rd year of the Integrated Master of Engineering and Industrial Management at the University of Minho The goal was to teach theoretical concepts associated to automation topics. The practical aspects as designing an automated machine or developing the corresponding Ladder Logic diagram is often well accepted by students. On the other hand, topics related to instrumentation, sensor type and functioning for example, more theoretical, are usually less attractive to students. So, different tools have been developed and tested along the past years to overcome this concern. This paper presents the last experience tested: evaluating a previously developed APP Inventor tool (developed by students) as wondering if it is a suitable way to learn automation; an automation conquest, where the competition may promote the stimulus to learn.
2014
Authors
Pires, EJS; Machado, JAT; Oliveira, PBM;
Publication
Mathematical Methods in Engineering
Abstract
The paper addresses new perspective of the PSO including a fractional block. The local gain is replaced by one of fractional order considering several previous positions of the PSO particles. The algorithm is evaluated for several well known test functions and the relationship between the fractional order and the convergence of the algorithm is observed. The fractional order influences directly the algorithm convergencerate demonstrating a large potential for developments. © Springer Science+Business Media Dordrecht 2014.
2017
Authors
de Moura Oliveira, PBD; Solteiro Pires, EJS; Boaventura Cunha, JB;
Publication
INTELLIGENT ENVIRONMENTS 2017
Abstract
This paper provides a bare-bone introduction to evolutionary and bio-inspired metaheuristic in the context of environmental greenhouse control. Besides presenting general evolutionary algorithm principles, specific details are provided regarding the genetic algorithm, particle swarm optimization and differential evolution techniques. A review of these algorithms within greenhouse control applications is presented, both for single and multiple objectives, as well as current trends.
2015
Authors
Oliveira, PM; Vrancic, D; Freire, HF;
Publication
CONTROLO'2014 - PROCEEDINGS OF THE 11TH PORTUGUESE CONFERENCE ON AUTOMATIC CONTROL
Abstract
A dual mode control configuration involving open-loop feedforward control to deal with set-point tracking and proportional integrative and derivative control to deal with disturbance rejection is proposed. The feedforward controller is a Posicast pre-filter shaping the reference input using either two or three steps. The switching between the open-loop and closed-loop control is performed automatically. The particle swarm optimization algorithm is deployed as design tool both for the feedforward and PID controller. Simulation results are presented showing the merits of the proposed technique.
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