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- Real-time control of a laboratory heat exchanger using the particle swarm optimisation algorithmPublication . Coelho, João Paulo; Cunha, José Boaventura; Oliveira, Paulo de MouraIn the past decade, evolutionary based algorithms have been a popular research theme in many disciplinary areas like control systems. Although, due to the computational load required, this type of algorithms usually are applied off-line. In this paper, a stochastic search algorithm known as particle swarm is used as an optimisation tool for on-line control of a custom made laboratory thermodynamic system.
- Extended stability conditions for CDM controller designPublication . Coelho, João Paulo; Boaventura-Cunha, José; Oliveira, Paulo de MouraThe coefficient diagram method (CDM) is one of the easiest methods for model based control system design. Its core is based on an algebraic method but it also encompasses a graphical analysis diagram that helps the user to evaluate the three main closed-loop system requirements: dynamic behaviour, robustness and stability. This later characteristic is analysed by a set of stability conditions derived from the previous work of Lipatov and Sokolov on sufficient conditions for stability. However, in CDM, only a fraction of the total conditions are considered. This work will show that this fact increases the inconclusive area within the stability space. Moreover an extended set of CDM stability conditions, in conjunction with its graphical interpretation, will be presented
- Prototyping and control of an automatic ceramic tableware finishing devicePublication . Alvarez, Mariano Jose; Brancalião, Laiany Suganuma; Gomes, Diogo; Pinto, Vítor H.; Carneiro, Jorge; Santos, José; Coelho, João Paulo; Gonçalves, JoséThis paper presents a first prototype of an automated system that will be applied in stoneware tableware ceramics finishing, being developed in the scope of STC 4.0 HP project. The main objective of this prototype is to test different alternatives to obtain a precise finish on ceramic pieces produced by GRESTEL - PRODUTOS CERÂMICOS S.A, improving the production of irregular pieces that until now are finished using manual labor. This is why the implementation of a closed-loop control of the rotation speed of a finishing sponge and its applied force control is proposed.
- Automated ceramics tableware finishing: non-circular geometries case studyPublication . Alvarez, Mariano Jose; Brancalião, Laiany Suganuma; Carneiro, Jorge; Costa, Paulo Gomes da; Coelho, João Paulo; Gonçalves, JoséThis paper is devoted to present the most recent results regarding the ongoing work carried out in the scope of the STC 4.0 HP project, which aims to automate the finishing process of ceramic tableware at the GRESTEL S.A. industry, focusing on non-circular shaped plates. A collaborative robot is in charge of handling the tableware and making it go around its entire perimeter through a sponge, to perform the finishing. An array, with the distances from the center to the different points of the plate, is applied as data to trace the path that the robot must follow. The final goal of this prototype is to obtain an even finish while maintaining a constant force along the entire perimeter of the ceramic tableware. After carrying out a series of tests, it was possible to conclude that the current approach was able to manipulate 3D-printed tableware made for testing and travel its perimeter to carry out the finishing.
- Evolutionary based BEL controller applied to a magneto-rheological actuatorPublication . Braz-César, Manuel; Coelho, João Paulo; Gonçalves, JoséThis paper addresses the problem of finding the best Brain Emotional Learning (BEL) controller parameters in order to improve the response of a single degree-of-freedom (SDOF) structural system under an earthquake excitation. The control paradigm considered is based on a semi-active system to control the dynamics of a lumped mass-damper-spring model, being carried out by changing the damping force of a magneto-rheological (MR) damper. A typical BEL based controller requires the definition of several parameters which can be proved difficult and nonintuitive to obtain. For this reason, an evolutionary based search technique has been added to the current problem framework in order to automate the controller design. In particular, the particle swarm optimization (PSO) method was chosen as the evolutionary based technique to be integrated within the current control paradigm. The obtained results suggest that, indeed, it is possible to parametrize a BEL controller using an evolutionary based algorithm. Moreover, simulation shows that the obtained results can outperform the ones obtained by manual tuning each controller parameter individually.
- Bang-bang temperature controller for a custom-made SMD reflow ovenPublication . Rezende, Rafael Luis Yanase de; Coelho, João PauloThis paper present the preliminary results regarding the application of a simple bang-bang control strategy to a custom-made SMD reflow oven. This appliance was built by retrofitting a recycled electric oven where both measurement and actuation chains are included. It will be shown that set-point tracking cannot be attained accurately and that severe temperature oscillations are observed.
- Model predictive control in greenhousesPublication . Coelho, João Paulo; Boaventura-Cunha, JoséIt is a somewhat general consensus that the agricultural production process has begun over 12,000 years ago somewhere in the Middle East region. The development of this activity can be explained in several ways, but all boils down to the necessity of hunter-gatherer-based humans to reduce their dependence on the whims of nature. Having control of the food chain was, and still is, one of the characteristics that made our species strive, flourish, and spread across the globe.
- Evolutionary-based BEL controller applied to a magneto-rheological structural systemPublication . Braz-César, Manuel; Coelho, João Paulo; Gonçalves, JoséThis work addresses the problem of finding the best controller parameters in order to improve the response of a single degree-of-freedom structural system under earthquake excitation. The control paradigm considered is based on brain emotional learning (BEL) and the actuation over the building dynamics is carried out by changing the stiffness of a magneto-rheological damper. A typical BEL-based controller requires the definition of several parameters which can prove difficult and non-intuitive to obtain. For this reason, an evolutionary-based search technique has been added to the current problem framework in order to automate the controller design. In particular, the particle swarm optimization method is chosen as the evolutionary based technique to be integrated within the current control paradigm. The obtained results suggest that, indeed, it is possible to parametrize a BEL controller using an evolutionary-based algorithm. Moreover, a simulation shows that the obtained results can outperform the ones obtained by manual tuning each controller parameter individually.
- Greenhouse heat load prediction using a support vector regression modelPublication . Coelho, João Paulo; Cunha, José Boaventura; Oliveira, Paulo de Moura; Pires, Eduardo S.Modern greenhouse climate controllers are based on models in order to simulate and predict the greenhouse environment behaviour. These models must be able to describe indoor climate process dynamics, wchich are a function of the both the control actions taken and the outside climate. Moreover, if predictive or feedforward control techniques are to be applied, it is necessary to employ models to describe and predict the weather. From all the climate variables, solar radiation is the one with greater impact in the greenhouse heat load. Hence, making good predictions of this physical quantity is of extreme importance. In this paper, the solar radiation is represented as a time-series and a support vector regression model is used to make long term predictions. Results are compared with the ones achieved by using other type of models, both linear and non-linear.
- Performance enhancement of a Neato XV-11 laser scanner applied to mobile robot localization: a stochastic modeling approachPublication . Gonçalves, José; Coelho, João Paulo; Braz-César, Manuel; Costa, Paulo Gomes daLaser scanners are widely used in mobile robotics localization systems but, despite the enormous potential of its use, their high price tag is a major drawback, mainly for hobbyist and educational robotics practitioners that usually have a reduced budget. The Neato XV-11 Laser Scanner is a very low cost alternative, when compared with the current available laser scanners, being this fact the main motivation for its use. The modeling of a hacked Neato XV-11 Laser Scanner allows to provide valuable information that can promote the development of better designs of robot localization systems based on this sensor. This paper presents, as an example, the performance enhancement of a Neato XV-11 Laser Scanner applied to mobile robot self-localization, being used as case study the Perfect Match Algorithm applied to the Robot@Factory competition.