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2017 | Book

CONTROLO 2016

Proceedings of the 12th Portuguese Conference on Automatic Control

Editors: Paulo Garrido, Filomena Soares, António Paulo Moreira

Publisher: Springer International Publishing

Book Series : Lecture Notes in Electrical Engineering

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About this book

The biennial CONTROLO conferences are the main events promoted by

The CONTROLO 2016 – 12th Portuguese Conference on Automatic Control, Guimarães, Portugal, September 14th to 16th, was organized by Algoritmi, School of Engineering, University of Minho, in partnership with INESC TEC, and promoted by the Portuguese Association for Automatic Control – APCA, national member organization of the International Federation of Automatic Control – IFAC.

The seventy-five papers published in this volume cover a wide range of topics. Thirty-one of them, of a more theoretical nature, are distributed among the first five parts: Control Theory; Optimal and Predictive Control; Fuzzy, Neural and Genetic Control; Modeling and Identification; Sensing and Estimation.

The papers go from cutting-edge theoretical research to innovative control applications and show expressively how Automatic Control can be used to increase the well being of people.

Table of Contents

Frontmatter

Control Theory

Frontmatter
Input-State-Output Representations of Concatenated 2D Convolutional Codes

In this paper we investigate a novel model of concatenation of a pair of two-dimensional (2D) convolutional codes. We consider finite-support 2D convolutional codes and choose the so-called Fornasini-Marchesini input-state-output (ISO) model to represent these codes. More concretely, we interconnect in series two ISO representations of two 2D convolutional codes and derive the ISO representation of the obtained 2D convolutional code. We provide necessary condition for this representation to be minimal. Moreover, structural properties of modal reachability and modal observability of the resulting 2D convolutional codes are investigated.

Diego Napp, Raquel Pinto, Rita Simões
MDP Periodically Time-Varying Convolutional Codes

In this paper we use some classical ideas from linear systems theory to analyse convolutional codes. In particular, we exploit input-state-output representations of periodic linear systems to study periodically time-varying convolutional codes. In this preliminary work we focus on the column distance of these codes and derive explicit necessary and sufficient conditions for an (n, 2, 1) periodically time-varying convolutional code to have Maximum Distance Profile (MDP).

Ricardo Pereira, Paula Rocha, Diego Napp
Periodic Event-Triggered Swing-Up Control of the Inverted Pendulum

In this paper, a novel strategy for swinging up an inverted pendulum is proposed. The strategy combines an energy-based control law with an event triggering condition to minimize transmissions, protect actuators and save energy. In addition, the strategy is periodic event-triggered, which provides two main advantages: An analytical way to determine a priori the sampling period to guarantee the appropriate behavior and an easy implementation in real prototypes.

E. Aranda-Escolástico, F. Gordillo, M. Guinaldo, S. Dormido
A Simplified Control Approach for the Neuromuscular Blockade Level

In this paper a new simplified control scheme for the neuromuscular blockade level that only requires the knowledge of one model parameter is proposed. The control law is designed to track a desired target neuromuscular blockade level. Furthermore, an identification procedure to obtain the necessary model parameter is implemented. The results were validated by simulations based on real data collected during surgeries.

Juliana Almeida, Teresa Mendonça, Paula Rocha
Disturbance Rejection Improvement for the Sliding Mode Smith Predictor Based on Bio-inspired Tuning

This paper addresses a strategy to improve disturbance rejection for the Sliding Mode Controller designed in a Smith Predictor scheme (SMC-SP), with its parameters tuned through the bio-inspired search algorithm—Particle Swarm Optimization (PSO). Conventional SMC-SP is commonly based on tuning equations derived from step response identification, when First Order Plus Dead Time models (FOPDT) are considered and therefore controller parameters are previously set. Online PSO tuning based on minimization of the Integral of Time Absolute Error (ITAE) can provide faster recovery from external disturbances without significant increase of energy consumption, and the Sliding Mode feature deals with possible model mismatch. Simulation results for time delayed systems corroborating these benefits are presented.

Josenalde Oliveira, José Boaventura-Cunha, Paulo Moura Oliveira
Quadruple Real Dominant Pole Tuning of a Filtered PID Controller

This paper proposes an integrated tuning of a two degree of freedom (2DOF) PID controller extended by an nth order binomial low pass filter for first order plant with dead time. The task is motivated by enabling an flexible achievement of a required measurement noise attenuation. By comparing two modifications of a quadruple real dominant pole tuning derived for two elementary situations it proposes a simplified tuning modification that may be easily applied to a general situation.

Mikuláš Huba, Pavol Bisták
Smith Predictor Tuned Through Fuzzy Fractional PID Controller

In this paper we study the control of a stable oscillatory system with a time delay, based on the application of the fractional calculus concepts. In this perspective, several algorithms are investigated and compared, when integrated within a Smith predictor structure with a fuzzy fractional PD$$^\beta $$+I controller in which the parameters are optimized by a genetic algorithm. Simulations are presented assessing the performance of the proposed fractional algorithms.

Isabel S. Jesus, Ramiro S. Barbosa
The Model-Based Disturbance Rejection with MOMI Tuning Method for PID Controllers

The paper presents a tuning method for PID controllers which substantially improves closed-loop disturbance rejection performance while keeping the tracking performance. The tuning method is based on the internal disturbance compensator which parameters are calculated according to the Magnitude Optimum criterion. The results of experiments show that the proposed model-based approach gives superior disturbance-rejection response and lower controller activity when compared to Disturbance Rejection Magnitude Optimum tuning method.

Damir Vrančić, Paulo Moura Oliveira, Jan Cvejn
Systemic Coordination Through Numeraires: Initial Simulation Results

This paper presents initial results on the development of a paradigm for the coordination of large multi-agent systems abstracted from social coordination processes using money. We recall basic concepts and report on the development of a simulator for modeled systems. We present a “toy” example together with the determination and simulation of a steady-state for it. Next, we show results of perturbing the system parameters and the initial values of state variables in the steady-state. We conclude by reviewing the presented results, sketching a roadmap for development and considering the paradigm in a wider theoretical control perspective.

Paulo Garrido, Pedro Osório
Wormhole Approach to Control in Distributed Computing Has Direct Relation to Physics

The topic of Wormholes in distributed computing is about creating two different realms with different characteristics, the synchronous Wormholes and the asynchronous payload with the goal of using the wormholes to control the synchronism of the payload processes. We describe the characteristics of Wormholes in distributed computing, and relate them to issues in Physics, specifically, wormholes in general relativity and entanglement in quantum mechanics. The entanglement in quantum mechanics is about the existence of fixed relations between different physical systems as if they were still the same system. The entanglement is made evident by the occurrence of decoherence, which transform the multiple outcome possibilities of quantum systems into a single outcome “classical physics”-like objective reality. It is here presented the similarity between the decoherence process in quantum physics and the consensus problem in distributed computing. The approach to quantum mechanics used is quantum Darwinism, a Darwinian approach to decoherence where the environment controls the outcome of a measurement. It is here proposed that wormhole systems can be used to implement environment-based control of distributed computing systems.

Nicolás F. Lori, Victor Alves
A New Robust Control Scheme for LTV Systems Using Output Integral Discrete Synergetic Control Theory

This paper presents a new robust control strategy based on a synergetic control theory (SCT) approach for linear time varying (LTV) systems in the presence of unknown persistent disturbance. The proposed control scheme is featured by an integral type of SCT driving the system towards a macro-variable manifold based on output error. The proposed control methodology guarantees robust stability for LTV systems, affected by unmeasured bounded additive disturbances. Robust stability analysis proves that the error trajectory monotonically converges to the SCT macro-variable manifold. The effectiveness of the proposed method and the implications of the controller design on feasibility and closed-loop performance is demonstrated through an example of reactor temperature control of Continuous Stirred Tank Reactor (CSTR) plant.

Saeid Rastegar, Rui Araújo, Alireza Emami, Abdelhamid Iratni

Optimal and Predictive Control

Frontmatter
Drug Administration Design for Cancer Gompertz Model Based on the Lyapunov Method

This article addresses the design of therapeutic procedures for cancer using a control based on the Gompertz model, that describes the nonlinear dynamics of tumor growth. The aim is to reduce the tumor size according to a decreasing target reference. The approach presented on this work uses a control Lyapunov function and yields an adaptive PI strategy that results from the exact linearization. It is concluded that the closed-loop system is globally asymptotically stable and is robust with respect to the presence of model parameter uncertainty.

B. Andrade Costa, J. M. Lemos
Sampled–Data Model Predictive Control Using Adaptive Time–Mesh Refinement Algorithms

We address sampled–data nonlinear Model Predictive Control (MPC) schemes, in particular we address methods to efficiently and accurately solve the underlying continuous-time optimal control problems (OCP). In nonlinear OCPs, the number of discretization points is a major factor affecting the computational time. Also, the location of these points is a major factor affecting the accuracy of the solutions. We propose the use of an algorithm that iteratively finds the adequate time–mesh to satisfy some pre–defined error estimate on the obtained trajectories. The proposed adaptive time–mesh refinement algorithm provides local mesh resolution considering a time–dependent stopping criterion, enabling an higher accuracy in the initial parts of the receding horizon, which are more relevant to MPC. The results show the advantage of the proposed adaptive mesh strategy, which leads to results obtained approximately as fast as the ones given by a coarse equidistant–spaced mesh and as accurate as the ones given by a fine equidistant–spaced mesh.

Luís Tiago Paiva, Fernando A. C. C. Fontes
Efficient Operations at Intermodal Terminals Using a Multi-agent System

Transport networks are large-scale complex systems whose objective is to deliver cargo at a specific time and at a specific location. Ports and intermodal container terminals behave as exchange hubs where containers are moved from a transport modality to a different one. Terminal operations management arise as a need to face the exponentially growth of the container traffic in the last few years. In this paper the Extended Formulation of the MPC is presented. This formulation accounts for the variation of the control action to reduce not only the amount of actions but to perform a wise and efficient use of handling resources. This formulation is based on the decomposition of the control action. The Extended Formulation is applied to a simulation case study based on a long-term scheduled scenario and compared with the Basic Formulation.

Tomás Hipólito, João Lemos Nabais, Miguel Ayala Botto
Model Predictive Control Applied to a Supply Chain Management Problem

Supply chains are ubiquitous in any commercial delivery systems. The exchange of goods and services, from different supply points to distinct destinations scattered along a given geographical area, requires the management of stocks and vehicles fleets in order to minimize costs while maintaining good quality services. Even if the operating conditions remain constant over a given time horizon, managing a supply chain is a very complex task. Its complexity increases exponentially with both the number of network nodes and the dynamical operational changes. Moreover, the management system must be adaptive in order to easily cope with several disturbances such as machinery and vehicles breakdowns or changes in demand. This work proposes the use of a model predictive control paradigm in order to tackle the above referred issues. The obtained simulation results suggest that this strategy promotes an easy tasks rescheduling in case of disturbances or anticipated changes in operating conditions.

Tatiana M. Pinho, João Paulo Coelho, António Paulo Moreira, José Boaventura-Cunha
Optimal Control for an Irrigation Problem with Several Fields and Common Reservoir

In a previous study, the authors developed the planning of the water used in the irrigation systems of a given farmland in order to ensure that the field cultivation is in a good state of preservation. In this paper, we introduce a model to minimize the water flowing into a reservoir that supplies different fields with different types of crops. This model is described as an optimal control problem where the water flow from a tap and the water used in the fields are the controls. The trajectories are described as the humidity in the soil and the amount of water in the reservoir.

Sofia O. Lopes, Fernando A. C. C. Fontes
Mechanical Multi-agent Maneuvering Using Noncooperative DMPC

Distributed Model Predictive Control is used to coordinate agents in multi-agent systems by managing set-points and coupling constraints. The coordination of multi-agent systems concept regards all type of control algorithms dependent on information interchange between subsystems. The control algorithms are developed to solve a series of static optimization problems with nonlinear coupling constraints by means of a typical receding horizon policy applied in predictive control design. For distributed scenarios, the motion of each agent is determined by the distributed algorithm as function of the information shared with the other agents making the individual behavior implicitly dependent on a global outcome or cost. The control algorithm is used to maneuver dynamically decoupled mechanical agents in a two dimensional scenario with obstacles avoidance. The found solution is meaningful to realize how Predictive Control can be an alternative to other solutions obtained through Dynamic Games, where the agents play an important role, in a strategic space, as game players or Computational Intelligence technique, where the agents present a self-organized behavior. Hence, the developed algorithm is useful to maneuver unmanned vehicles in mazes, formations and also for collision avoidance.

José Igreja, Filipe A. Barata, Carla Viveiros
A Parametrized NMPC Strategy for Pressure Reducing Valves

Water loss due to leakage is a major concern for water distribution operations. Being mainly caused by pipe deterioration and high values of pressure, these have several negative features. Pressure Reducing Valves (PRV) are used in water supply networks to keep the pressure under acceptable values in order to reduce physical water losses. However, such process presents several nonlinearities and physical constraints leading to a highly complex model. In this paper, a parameterized Nonlinear Model Predictive Control (NMPC) is proposed for the PRV combined with a water network. The NMPC consists in finding, at each sampling instant, an optimal solution over a prediction horizon taking into account the system nonlinearities and process constraints. Simulation results are proposed to show the efficiency of this control strategy and a performance comparison with standard PID control are also performed.

Carlos Felipe Ilha Pereira, André Murilo, Anderson Quadros, Walter de Britto Vidal Filho

Fuzzy, Neural and Genetic Control

Frontmatter
Fuzzy Kalman Filter Black Box Modeling Approach for Dynamic System with Partial Knowledge of States

A strategy to Fuzzy Kalman Filter identification, is proposed. A mathematical formulation applied to fuzzy Takagi-Sugeno structure is presented: the algorithm FCM estimates the antecedent parameters; from the input and output data of dynamic system, the ERA/DC algorithm based on FCM clustering algorithm, is applied to obtain the state matrix, input influence matrix, output influence matrix, and direct transmission matrix (the matrices A, B, C, and D, respectively) to each rule of the consequent parameters. The Fuzzy Kalman Filter is applied to estimate states and output of a dynamic system with partial knowledge of states and the efficiency of the proposed methodology is shown in computational results, once that the Fuzzy Kalman Filter follows the dynamic behavior related to output and states of the dynamic system.

Danúbia Soares Pires, Ginalber Luiz de Oliveira Serra
Neural Network Control Strategies Applied to a DC Motor with a Nonlinear Load

This paper investigates the use of neural networks in the design of control systems. For that, it was considered two different neural control structures, namely the stabilizing and the adaptive reference model control systems. The analysis tries to understand to which extent the introduction of neural networks improves a process control. The control systems are simulated and analyzed for several reference inputs with and without added noise in the sensor. The simulation results show the improved performance of the control systems with neural networks.

Luís M. M. Ferreira, Ramiro S. Barbosa
Grey Wolf, Gravitational Search and Particle Swarm Optimizers: A Comparison for PID Controller Design

Nature and biologically inspired metaheuristics can be powerful tools to design PID controllers. The grey wolf optimization is one of these promising and interesting metaheuristics, recently introduced. In this study the grey wolf optimization algorithm is proposed to design PID controllers, and the results obtained compared with the ones obtained with gravitational search and particle swarm optimization algorithms. Simulation results obtained with these three bio-inspired metaheuristics applied to a set of benchmark linear plants are presented, considering the design objective of set-point tracking. The results are also compared with two non-iterative PID tuning techniques.

Paulo Moura Oliveira, Damir Vrančić

Modeling and Identification

Frontmatter
Construction of Confidence Sets for Markov Chain Model

The problem of forecasting the state probabilities vector for a stationary Markov chain with discrete time in case of transition probabilities are not exactly known and measured during the system operation is investigated. An auxiliary dynamic system with uncertainty and observation showing the dynamics of the state probabilities vector is constructed. Two approaches to the determination of the guaranteed with a given probability estimates are proposed. The first approach uses confidence sets for rows of the matrix of transition probabilities and the ellipsoidal calculus. The second approach is based on simulation and finding a sample quantile of an objective function, which determines the form of a confidence set for the system state.

Dmitry Zavalishchin, Galina Timofeeva
Monitoring and Simulation of Gas Pipelines Through Quadripole Models

In this paper we propose to model a high pressure gas network using a quadripole approach. Although being simple, the proposed model seems to be adequate to network analysis and control, and is directly extendible to more complex networks, i.e., networks with junctions and loops. The model is proven to be liable on a case study constructed from data supplied by REN Gasodutos, where we investigate the effect of a leakage on the mass flow and pressure along the pipeline with the final objective to define a model based methodology for leakage detection and location.

S. T. Baltazar, T.-P. Azevedo Perdicoúlis, P. Lopes dos Santos
Data Based Modeling of a Large Scale Water Delivery System

Water is a vital resource and the growing populations and economies around the globe are pushing its demand worldwide. Therefore, the water conveyance operation should be well managed and improved. This paper proposes the development of reliable models able to predict water levels of a real 24.4 km water delivery channel in real time. This is a difficult task because this is a time-delayed dynamical system distributed over a long distance with nonlinear characteristics and external perturbations. Artificial neural networks are used, which are a well-known modeling technique that has been applied to complex and nonlinear systems. Real data is used for the design and validation of the models. The model obtained has the ability to predict water levels along the channel with minimum error, which can result in significant reduction of wasted water when implementing an automatic controller.

Marta Fernandes, Paulo Oliveira, Susana Vieira, Luís Mendonça, João Lemos Nabais, Miguel Ayala Botto
PDE Model for Leakage Detection in High Pressure Gas Networks

In this paper we design a model based method to locate a leakage and estimate its size in a gas network, using a linearised version of an hyperbolic PDE. To do this, the problem is reduced to two identical ODEs, allowing in this way for a representation of the pressure as well as the mass flow in terms of its system of fundamental solutions. Then using the available measurements at the grid boundary points, the correspondent coefficients can be determined. Assuming pressure continuity, we check for consistency of the coefficients in order to find faulty pipelines. Thence, the location of the leakage can be found either graphically or using a numerical method for a specific pipe. Next, its size can also be estimated.

T.-P. Azevedo Perdicoúlis, R. Almeida, P. Lopes dos Santos, G. Jank

Sensing and Estimation

Frontmatter
Sensorless Nonlinear Control of Fed-Batch Cultivation Bioprocess Using the State-Dependent Approach

The cultivation of Escherichia coli bacteria is widely used by geneticists and biopharmaceuticals to produce medicines and vaccines. In such industries, Bioprocesses are known by their harsh environment and very expensive physical sensors. This paper deals with nonlinear estimation and control of fed-batch Escherichia coli bioprocess. Enhancing the process performance and maximizing its efficiency by optimizing the control of Escherichia coli cultures depends on the availability of appropriate online sensors for the main culture components. In this study, an innovative method for nonlinear estimation and control of bioprocesses is designed and assessed. The new algorithm for control and estimation of Escherichia coli bioprocess states, based on the State-Dependent Riccati Equation technique, is validated by numerical simulation. The results obtained clearly demonstrate the effectiveness of the proposed technique for Biosystems in measuring, monitoring, and control of their natural nonlinear dynamics.

Abdelhamid Iratni, Rui Araújo, Saeid Rastegar, Mohammed Mostefai
Velocity and Brightness Control in Prototype for Blood Type Determination

This paper presents algorithms and methodologies used for controlling operating parameters of a prototype developed for the determination of human blood types. Being the illumination and mixing between blood and reagents keys for a secure identification of the test results (blood types), it becomes necessary to include, in the prototype, brightness and velocity control to increase the efficiency and safety of results.

Ana Ferraz, Vítor Carvalho, José Machado
Development of Soft Sensors Based on Analytical and Spectral Data on a Real Small Size Wastewater Treatment Plant

Advances in measurement and automation have recently enabled the deployment of monitoring systems with high frequency data acquisition in Wastewater Treatment Plants (WWTP). In this context, this work aims to design soft sensors to predict hard-to-measure wastewater quality variables required for mechanistic modeling of biological treatment in a real municipal WWTP. Input data collected at the WWTP using a flowmeter, online spectrophotometric and electrochemical probes, sampling campaigns and off-line analyses, are here used for the development of soft sensors through multivariate methods, i.e., Principal Component Analysis (PCA) and Partial Least Squares (PLS) regression. Exploratory data analysis is performed to detect outliers, patterns and correlations. Soft sensor PLS models are optimized using leave-one-out cross validation and the root mean squared error (RMSE) for the prediction of an independent dataset is computed. Normalized RMSE values for organic nitrogen prediction result in 19.5 % and 18.1 % for sensors using analytical and spectral data, respectively. The possibility of using a single wavelength spectrophotometric probe is here evaluated aiming to reduce the online monitoring investment costs.

C. Leitão, L. Fernandes, R. Ribeiro, M. C. Almeida, C. I. C. Pinheiro, H. M. Pinheiro
Solar Pyramidal Sensor

The use of solar radiation, as a renewable energy source, is a concern and a technological challenge of management and economic profitability. In this context it is paramount the knowledge about the position and movement of the Sun as well as the characteristics of sun radiation. Any new solution is required to bring a higher yield, better forecasting methods and better energy management, with lower technology costs and higher management effectiveness. This paper presents a simple and low-cost approach to determine the elevation and azimuth of the Sun, and the direct and diffuse radiation. This task is performed by a pyramid made of LDR sensor-coated surfaces connected to a microcontroller and a built-in mathematical model to compute the data. This device reads the radiation values of the sensors and sends them to a computer for further analysis, processing and presentation of useful information about the incoming sun radiation.

Paulo Salgado, Beatriz Pereira, Lara Félix, Paulo Afonso
Actuator Fault Detection and Isolation Based on Multiple-Model Adaptive Estimation (MMAE)

This paper proposes the application of Multiple-Model Adaptive Estimation (MMAE) to the detection and isolation of a broad category of actuator faults. An in-depth study on this methodology is provided, including the study of the asymptotic properties of the model probability signals for a non-discrete uncertainty domain. The design of the bank of filters is tackled by a performance-based design algorithm originally developed for the bi-dimensional additive fault model considered. Simulations are performed using a generic linearized model, enabling the validation of the methodology, and confirming the potentialities of the method for both fault diagnosis and estimation under model uncertainty.

Diogo Monteiro, Paulo Rosa, Paulo Oliveira, Carlos Silvestre

Robotics

Frontmatter
Wheels for Staircases

Our objective is to design innovative robot wheels capable of rolling on staircases, without sliding and without bouncing. This is the first step to reach the ultimate goal of building wheelchairs capable to overcome the obstacles imposed by staircases on people with limited mobility. We show that, given a staircase with equal steps, there is an infinite number of wheels that roll over it, with the constraints of no-sliding and no-bouncing. Some of these wheels appear to be very interesting for real applications. We also present an algorithm for the construction of a wheel, which depends only on the measures of the tread (the part of the staircase that is stepped on) and the riser (the vertical portion between each tread) of the step.

Fátima Silva Leite, Jorge Batista, Krzysztof Krakowski, André Carvalho, Tiago Cruz, Eduardo Domingues, André Lizardo, Gonçalo Saraiva
Imitate Me!—Preliminary Tests on an Upper Members Gestures Recognition System

This work describes the design, implementation, and preliminary tests of a system that uses a humanoid robot to mimic non-standard upper members gestures of a human body. The final goal is to use the robot as a mediator in motor imitation activities with children with special needs, either cognitive or motor impairments. A Kinect sensor and the humanoid robot ZECA (a Zeno R-50 robot from Hanson RoboKind) are used to identify and mimic upper members gestures. The system allows direct control of the humanoid robot by the user. The proposed system was tested in laboratory environment with adults with typical development. Furthermore, the system was tested with three children between 4 and 12 years old with motor and cognitive difficulties in a clinical-like environment. The main goal of these preliminary tests was to detect the constraints of the system.

Vinícius Silva, Pedro Leite, Filomena Soares, João Sena Esteves, Sandra Costa
Happiness and Sadness Recognition System—Preliminary Results with an Intel RealSense 3D Sensor

Systems and devices that can recognize human affects have been in development for a considerable time. Facial features are usually extracted by using video data or a Microsoft Kinect sensor. The present paper proposes an emotion recognition system that uses the recent Intel RealSense 3D sensor, whose reliability and validity in the field of emotion recognition has not yet been studied. This preliminary work focus on happiness and sadness. The system extracts the user’s facial Action Units and head motion data. Then, it uses a Support Vector Machine to automatically classify the emotion expressed by the user. The results point out the adequacy of Intel RealSense for facial features extraction in emotion recognition systems as well as the importance of determining head motion when recognizing sadness.

Vinícius Silva, Filomena Soares, João Sena Esteves, Joana Figueiredo, Cristina Santos, Ana Paula Pereira
A Simple Control Approach for Stereotactic Neurosurgery Using a Robotic Manipulator

In this paper, it is described a simple, expandable and easily integrable robotic system to be a direct replacement to the stereotactic frame in minimally invasive neurosurgeries. Robotic systems have several advantages over the traditional frame used in stereotactic neurosurgeries such as, improved precision, steadiness and flexibility. However, the robotic systems cleared to perform this procedure are closed and costly. A robotic manipulator was selected, based on repeatability, compactness and controller accessibility. The control application developed includes a registration module to calibrate the robot to the surgical reference frame and several algorithms that allow a precise and consistent, drilling and electrode guidance. Safety was the most important factor when designing the control application, and several mechanisms were implemented that replicate the market cleared robotic systems.

Carlos Faria, Carolina Vale, Manuel Rito, Wolfram Erlhagen, Estela Bicho
Motion Control of Mobile Autonomous Robots Using Non-linear Dynamical Systems Approach

This paper presents a solution to the problem of motion control of an autonomous robot, moving in a dynamical and unstable environment. It is based on non-linear dynamical systems, modelling the state variables that define the motion of a robot under an omnidirectional platform, like its direction of navigation and velocity. The approach used, is based on a set of non-linear differential equations that model the evolution of state variables along time, based on the concept of attractors and repellers. In the official RoboCup Middle Size League field, a target is used to attract the robot to a certain position (could be the ball or a desired position to receive the ball), while a repeller could move the robot away from its original path (given by obstacles in the surrounding environment). The research was firstly carried out in a computational simulation environment and later on with robots in a real environment.

Fernando Ribeiro, Gil Lopes, Tiago Maia, Hélder Ribeiro, Pedro Osório, Ricardo Roriz, Nuno Ferreira
Autonomous UAV Outdoor Flight Controlled by an Embedded System Using Odroid and ROS

Unmanned Aerial Vehicles (UAVs) have become a prominent research field due to their vast applicability and reduced size. An appealing aspect of the UAVs is the ability to accomplish autonomous flights in several contexts and purposes, and a variety of applications have been developed, from military to civilian fields. The system proposed in this work is a novel and simplified interaction between the user and the UAV for autonomous flight, where the necessary computation is performed in an embedded computer, decreasing response time and eliminating the necessity of long-distance communication links with base stations. Results are presented with both hardware in the loop simulations and a real UAV using Pixhawk, and Odroid and ROS as companion computer and software platform for code development.

João Pedro Carvalho, Marco Aurélio Jucá, Alexandre Menezes, Leonardo Rocha Olivi, André Luis Marques Marcato, Alexandre Bessa dos Santos
Tracking of Physiotherapy Exercises Using Image Processing Techniques

It is increasing the number of people with reduced mobility as a result of neurological disease. This impairment requires adequate physical therapy plans to improve the quality of life. Serious games are able to give an important contribution in the field of physiotherapy, as they create a pleasant environment to lead patients to overcome the lack of motivation they may feel with the repetitive and boring exercises of traditional physical therapy. We have developed a serious game for physical therapy of patients with neurological diseases, based on image processing techniques, allowing monitoring some exercises.

Tiago Martins, Vítor Carvalho, Filomena Soares
Inside Pipe Inspection: A Review Considering the Locomotion Systems

It is possible to observe that the fast technological development in the fields of instrumentation, control and embedded systems are increasing the employment of robotic systems for the execution of a large variety of tasks, for example, oil exploration or load transportation. In this way, there are many situations where it is very reasonable to use automatized systems, with special attention to the inspection of pipelines in the oil industry. There is a large quantity of systems developed and in the literature it is possible to find several reviews about inspection robots considering specifics applications. However, none of those reviews presents the methodology to acquire defect’s position. The main objective of this paper is to review the technical literature, describing the differences between robots employed to internal pipe inspection considering some features as application, adaptability, locomotion, sensors inspection and odometers.

Everson Brum Siqueira, Rodrigo Zelir Azzolin, Silvia Silva da Costa Botelho, Vinícius Menezes de Oliveira

Mechatronics

Frontmatter
SmartBath: A New Bathing Concept for Disabled People

Nowadays, the development of equipment for the elderly care is of great importance due to the increased number of elderlies. The requirements and failures of the existing elderly-care devices were studied in order to identify the most important needs of the bathing activity and then a new concept is proposed ‘SmartBath’. The SmartBath is a new assistive technology to improve autonomy, quality, safety, comfort and hygiene of bathing for elderly or bedridden. The bathing is a daily activity that requires physical effort, dedication and time to perform from the caregiver. This new concept integrates an automatic control of the bathing temperature, water flow-rate and light intensity. This concept can be operated directly or remotely into the system using mobile devices.

Karolina Bezerra, José Machado, Filomena Soares, Vítor Carvalho, Demétrio Matos
A New Approach for Dynamic Analysis of Overhead Crane Systems Under Moving Loads

Nowadays, dynamic effects of overhead cranes are usually neglected because of their operation at low speed but they can be designed considering the static effects. However, the production rate increases with the development of technology and the increase in the number of proper places for product handling and cargo ships loading in the harbour. So the need for working cranes is growing. Therefore, in this study we have analysed both single bridge and double bridges crane systems and the load dynamic effects occurring on the bridge during the movement of carriages. The analysis was based on the Finite Element Method (FEM). The conclusion of the study was that double bridge cranes have had less dynamic effects under the same loads as single bridge cranes so they proved to be working faster.

Şahin Yildirim, Emir Esim
CMOS Transducer with Linear Response Using Negative Capacity that Can Be Used in Mechatronic Systems for Force Measurement in Human Walking Analysis and in the Future in MEMS and NEMS Applications

The paper describes a methodology to linearize the signals obtained from capacitive force sensors. The approach is based on the theoretical analysis of a negative capacitance circuit adjusted to compensate to the parasitic capacitances that are formed in parallel with the sensor. I describe an original method of linearization using a negative capacitance calculated based on the Laplace Analysis of the one auxiliary circuit added to the main oscillator. This auxiliary circuit, called “Neutrodyne” is a neutralization circuit and provides a negative capacitance that compensates the parasitic one. The result is a rectangular signal with linear frequency dependent on the force or pressure applied. This linearization method can be used in a variety of other applications: mechatronic systems, gait analysis, microelectromechanical systems (MEMS) and nanoelectromechanical systems (NEMS). In our project, the transducer is used for measuring the calibrated Ground Reaction Force during gait in order to calculate the total caloric consumption of the body for horizontal components of forces application points.

Anghel Constantin, Gheorghe I. Gheorghe
Behavior of the Elastomers Used in Prehension Systems for Small Cylindrical Objects

To use the elastomers as a interfacial surface in the prehension systems, the authors experimentally determined the elastic deformation and sliding friction of a plane elastomer sample in contact with small steel roller for normal loads up to maximum 9 N and linear speed of 0.1 mm/s. The experiments were realized on a Tribometer CETR UMT 2, by using two procedures: firstly was determined the Young’s modulus of the elastomer by indentation with a steel roller with normal loads between 1 and 9 N and secondly was determined the friction forces in sliding of the steel roller on elastomer sample with normal loads between 1 and 5 N. On contact surfaces was experimentally determined the total friction force including both elastic deformation force and sliding force. Also, an analytical model for friction force has been developed.

Vlad Cârlescu, Mihai Adrian Rusu, Gheorghe Prisăcaru, Emanuel Miron, José Machado, Dumitru Olaru

Manufacturing Systems and Scheduling

Frontmatter
Collaborative Portal for Supporting Manufacturing Resources Selection in a Global Market

In the last decades the manufacturing industry has shifted from largely single location centralized manufacturing towards networked manufacturing spread over multiple sites. Companies have either established new production sites in multiple locations or established strategic partnerships to respond to market changes more rapidly as well as for more efficient and effective sharing of resources, through the so-called integrated manufacturing systems environments. In this context, proper collaboration among different locations and/or partners becomes more critical. Thus, development of appropriate integrated tools, to enable clients or network partners to accurately select appropriate manufacturing resource from the widened global market context, becomes emergent. Therefore, this work is aimed at providing a contribution to maximize overall benefit of businesses, in the context of a networked scenario, and subject to a set of configurations and restrictions on part of the manufacturing resources providers and searchers. Thus, the authors propose a collaborative portal to enable to perform a better manufacturing resources selection, based on technologies integration for supporting accurate orders processing.

Vaibhav Shah, Maria Leonilde Rocha Varela, Goran D. Putnik
A Simulation Platform Prototype for Evaluating Alternative Scenarios of Members Integration in Virtual Organizations

Companies are facing growing challenges motivated by globalization. A globalized market means that the number of companies with which they will need to compete to maintain or enlarge their market share is increased. Additionally, it also brings greater opportunities to conquer new markets and increase existing market shares, since the geographical, political and economical boundaries are gradually being removed. This paper proposes and illustrates the use of a platform prototype for enabling the evaluation and selection of attractive members for being included as members in a virtual organization. An extended simulation study is described and results obtained presented which show advantage of a used dynamic evaluation and selection model, based on a varying set of criteria.

António Arrais-Castro, Gaspar Vieira, Maria Leonilde Rocha Varela, Goran D. Putnik, José Machado
Formal Analysis of an Urban Road Traffic Model

The paper proposes a method based on timed automata to validate different road traffic control scenarios. In order to estimate the current traffic state, a strategy in which a special attention was given to information collected from the streets converging to main crossroads was elaborated. Then, the up to dated information was used by a complex road traffic model to improve the traffic flow. The validation and verification of the road traffic model was realized using UPPAAL model-checker. A representative area of Cluj Napoca city center was modeled and simulated in order to determine the right parameters for traffic control. The proposed model, validated in UPPAAL, can be extended to any road structure for analysis purposes.

Camelia Avram, Eduardo Valente, Adina Aştilean, José Machado, Dan Radu

Vibration Control

Frontmatter
Brain Emotional Learning Based Control of a SDOF Structural System with a MR Damper

This paper describes the application of a Brain Emotional Learning (BEL) controller to improve the response of a SDOF structural system under an earthquake excitation using a magnetorheological (MR) damper. The main goal is to study the performance of a BEL based semi-active control system to generate the control signal for a MR damper. The proposed approach consists of a two controllers: a primary controller based on a BEL algorithm that determines the desired damping force from the system response and a secondary controller that modifies the input current to the MR damper to generate a reference damping force. A parametric model of the damper is used to predict the damping force based on the piston motion and also the current input. A Simulink model of the structural system is developed to analyze the effectiveness of the semi-active controller. Finally, the numerical results are presented and discussed.

Manuel Braz César, José Gonçalves, João Coelho, Rui Carneiro de Barros
Pendulum TMD’s in Building Vibration Control

The theory behind small amplitude movement of a pendulum is stated, followed by construction of a simple example with two degrees of freedom including the unidirectional movement of the structure and the pendulum angle in relation to vertical. This simple model and the finite elements software SAP2000 are also applied to a multiple degree of freedom one bay-frame building. The application of the pendulum TMD to control the building vibrations is validated by numerical modelling. An additional case with a more complex model was also studied, comprising a reaction tower of a transmission tower testing station which dynamic behavior under wind action is benefited from placement of a pendulum TMD. The numerical modelling of the studied indicate that the application of pendulum TMD’s is worthwhile in civil engineering structures.

Rui Carneiro de Barros, Catarina M.A. Sousa
Fuzzy Based Control of a Vehicle Suspension System Using a MR Damper

Vehicle suspension systems are usually based on passive actuators and control modes in which the damping and stiffness parameters are predefined and kept constant for all road profiles and vehicle response. A different approach is to use active systems to monitor and control the suspension motion in order to improve the vehicle handling and comfort. However, these systems have a complex design requiring a relatively high power source to operate. Semi-active systems are also capable to modify the properties of the vehicle suspension but with low power requirements making them a promising technology for demanding vibration control systems. This paper presents the findings of a numerical simulation involving a simplified model of a vehicle suspension system equipped with a MR actuator. The system is designed to improve the behavior (comfort and handling) of the vehicle compared with a traditional passive suspension system. A simple fuzzy logic controller is used to decide the control action in accordance with the measured system response.

Kellie F. Oliveira, Manuel Braz César, José Gonçalves
Milling Parameters Optimization for Surface Quality

The Taguchi method is a powerful tool to experiment design optimization and is used in this work to optimize the cutting parameters, which reduce the chatter effect on surface quality. The present study includes feed per tooth, cutting speed, radial and axial depth of cut as control factors. An orthogonal array of L16 was used with the ANOVA analyses in order to identify the significant factors associated to the surface roughness and chatter vibration in three different directions. The optimal cutting combination for the surface finishing was determined through the analysis of surface roughness. This are correlated with the vibrations levels recorded during the experimental tests. The study was carry-out by machining a hardened steel block with tungsten carbide coated tools. The results led to the minimum of arithmetic mean surface roughness of 1.05 µm which corresponded to a minimum of the mean vibration level.

Tânia Dias, Nuno Paulo, Luís Queijo, Hernâni Reis Lopes, Manuel Braz César, João Eduardo Ribeiro

Applications in Agricultural Systems

Frontmatter
Automation and Control in Greenhouses: State-of-the-Art and Future Trends

This paper presents the state-of-the-art in terms of automation and control for protected cultivation in greenhouses. Aspects such as modeling, instrumentation, energy optimization and applied robotics are considered, aiming at not only to identify latest research topics, but also to foster continuous improvement in key cutting-edge problems.

Josenalde Oliveira, José Boaventura-Cunha, Paulo Moura Oliveira
A New Plant Growth System Rig Based on Thermodynamic Solar Energy: A Study for Energy Efficiency Assessment

At the present there is a high pressure toward the improvement of all production processes. Those improvements can target distinct factors along the production chain. In particular, and due to recent tight energy efficiency policies, those that involve energy efficiency. As can be expected, agricultural processes are not immune to this tendency. Even more when dealing with indoor productions. In this context, this work presents an innovative system that aims to improve the energy efficiency of a trees growing platform. This improvement in energy consumption is accomplished by replacing an electric heating system by one based on thermodynamic panels. The assessment of the heating fluid caudal and its temperature was experimentally obtained by means of a custom made scaled prototype whose actuators status are commanded by a Fuzzy-based controller. The obtained results suggest that the change in the heating paradigm will lead to overall savings that can easily reach 60 % on the energy bill.

João Paulo Coelho, José Gonçalves, Manuel Braz César, José Dias
Model Predictive Control of a Conveyor-Based Drying Process Applied to Cork Stoppers

Control applications are a key aspect of current industrial environments. Regarding cork industries, there is a particular process that needs to be addressed: the cork stoppers drying. Currently the methodology used in this process delays the overall production cycle and lacks in the drying efficiency itself. This paper presents the development of a cork stopper drying system based on the control of a conveyor based machine using Model Predictive Control (MPC). Throughout the project it was also developed a drying kinetics model for the cork stoppers and an extension of such model to a discrete space state model. By applying the proposed methodology it is assured the cork stoppers’ drying in a faster and more efficient way.

Pedro Tavares, Tatiana M. Pinho, José Boaventura-Cunha, António Paulo Moreira
Robust Control of Agroindustrial Drying Process of Grains Based on Sliding Modes and Gravitational Search Algorithm

This paper proposes the recently introduced Gravitational Search Algorithm (GSA) to tune a Sliding Mode Controller (SMC) applied on the temperature control of a grains drying system. The problem of maintaining the temperature precisely adjusted inside a silo is relevant to avoid thermal damage and spoilage losses, and thus guarantee the right conditions for storage. The objectives of set-point tracking and disturbance rejection are incorporated into the minimization of the integral of the time-weighted absolute error. Simulation results are presented and compared with PID and with SMC tuned by Particle Swarm Optimization (PSO) and by earlier proposed tuning equations.

Josenalde Oliveira, José Boaventura-Cunha, Paulo Moura Oliveira

Power Systems Applications

Frontmatter
Model Predictive Current Control of a Slow Battery Charger for Electric Mobility Applications

This paper presents a model predictive current control applied to a slow electric vehicle (EV) battery charger. Taking into account the similarities between the power converters inside the EV, it is possible to combine the battery charger and the motor driver in a single integrated converter, thus reducing the weight and volume of the proposed solution, and also contributing to reduce the final price of the EV. Due to the bidirectional power flow capability of the integrated power converter, when working as a slow EV battery charger it can operate in grid-to-vehicle (G2V) mode and in vehicle-to-grid (V2G) mode, contributing to make EVs an important assets in the future smart grids. The integrated power converter working as battery charger operates with sinusoidal current and unitary power factor, contributing to improve the power quality of the electrical grid. This paper provides simulation and experimental results that validate the model predictive control algorithm applied to the proposed integrated power converter working as slow EV battery charger.

Delfim Pedrosa, Ricardo Gomes, Vitor Monteiro, José A. Afonso, João L. Afonso
Comprehensive Analysis and Comparison of Digital Current Control Techniques for Active Rectifiers

This paper presents a comprehensive analysis and comparison of digital current control techniques for active rectifiers. These rectifiers are connected to the power grid and are controlled aiming to obtain sinusoidal grid currents and unitary power factor. In this context this paper presents the principle of operation of a full-bridge full-controlled active rectifier, which is controlled by different digital current control techniques, namely, proportional-integral (PI) in stationary frame, PI in synchronous frame, PI sinewave (PIS), feedforward, sliding mode, and predictive. These digital current control techniques are explained in detail and is established a comparison in terms of their current errors in steady-state, as well as in terms of their digital implementation using the digital signal processor (DSP) TMS320F28335 from Texas Instruments.

Vítor Monteiro, João C. Ferreira, Delfim Pedrosa, M. J. Sepúlveda, J. C. Aparício Fernandes, João L. Afonso
Digital Control of a Novel Single-Phase Three-Port Bidirectional Converter to Interface Renewables and Electric Vehicles with the Power Grid

This paper presents the digital control of a novel single-phase three–port bidirectional (STB) converter used to interface renewables from solar photovoltaic (PV) panels and electric vehicles (EVs) with the power grid. Using an appropriated power theory, the STB converter can be used to exchange energy between the PVs, the EVs and the power grid in four distinct modes: (1) The EV receives energy from the power grid (G2 V—grid–to–vehicle operation mode) or delivers energy to the power grid (V2G—vehicle–to–grid operation mode); (2) All the energy produced by the PV panels is delivery to the power grid; (3) All the energy produced by the PV panels is delivery to the EV; (4) The EV can receive energy simultaneously from the PV panels and from the power grid (G2 V). The currents of the power grid, PV panels and EV are controlled through independent predictive current control strategies, which ensure good power quality levels. This paper presents the architecture of the proposed STB converter and the detailed explanation of the digital implementation of the control algorithms, namely, the power theory and the predictive current control strategies. The control algorithms were validated through computational simulations and experimental results.

Vítor Monteiro, José A. Afonso, Delfim Pedrosa, Júlio S. Martins, João L. Afonso
Model Predictive Control of an On-Board Fast Battery Charger for Electric Mobility Applications

Under the necessities of reducing emissions and air pollution, and also for increasing fuel economy, automotive companies have been developing electric and plug-in hybrid electric vehicles. Since these vehicles are parked when the batteries are being charged, it is possible to use the traction power converter as on-board charger, also allowing to reduce weight, volume and costs of components in the vehicle. In this context, this paper presents a model predictive control algorithm for an on-board fast battery charging that uses the traction power converter of an electric vehicle. Simulation results and system implementation are depicted, and finally, are presented some experimental results obtained with the proposed control system.

Delfim Pedrosa, Ricardo Gomes, Vitor Monteiro, J. C. Aparício Fernandes, João Monteiro, João L. Afonso
Family Houses Energy Consumption Forecast Tools for Smart Grid Management

This paper presents a short term (ST) load forecast (FC) using Artificial Neural Networks (ANNs) or Generalized Reduced Gradient (GRG). Despite the apparent natural unforeseeable behavior of humans, electricity consumption (EC) of a family home can be forecast with some accuracy, similarly to what the electric utilities can do to an agglomerate of family houses. In an existing electric grid, it is important to understand and forecast family house daily or hourly EC with a reliable model for EC and load profile (PF). Demand side management (DSM) programs required this information to adequate the PF of energy load diagram to Electric Generation (EG). In the ST, for load FC model, ANNs were used, taking data from a EC records database. The results show that ANNs or GRG provide a reliable model for FC family house EC and load PF. The use of smart devices such as Cyber-Physical Systems (CPS) for monitoring, gathering and computing a database, improves the FC quality for the next hours, which is a strong tool for Demand Response (DR) and DSM.

F. Rodrigues, C. Cardeira, J. M. F. Calado, R. Melício
Renewable Energy System for an Isolated Sustainable Social Centre

This paper describes the development of the power converters and control algorithms to implement an isolated microgrid based in renewable energy sources used to feed a Sustainable Social Centre in a remote place. The microgrid is designed to work with photovoltaic panels, micro–wind and micro-hydro turbines, or even with diesel generators. The control system of the power converters is totally digital and implemented by means of a TMS320f28335 Digital Signal Controller (DSC) from Texas Instruments. One of the most important requirements imposed for the microgrid power system is the capability of providing a sinusoidal supply voltage with low harmonic distortion even in the presence of non–linear electrical loads. The hardware topologies and the digital control systems of the power converters are evaluated through experimental results obtained with a developed laboratory prototype. This work is focused in the DC–AC converter of the renewable energy system for the isolated Sustainable Centre.

J. G. Pinto, Fábio Fernandes, Bruno Exposto, Vitor Monteiro, João L. Afonso
Evaluation of the Introduction of Electric Vehicles in the Power Grid—A Study for the Island of Maio in Cape Verde

This paper presents an evaluation of the introduction of electric vehicles (EVs) in an electrical power grid. The main contribution is the control analysis of the power quality considering simultaneous battery charging processes. The methodology used can be applied to any known power grid; however, it was considered the case of the island of Maio, in Cape Verde, in continuation of previous works concerning that power grid. Two commercial different types of battery chargers were considered: a traditional model with highly distorted current consumption (that causes distortion in the power grid voltage), and another with almost sinusoidal current consumption. Considering simultaneous battery charging processes, it can be concluded that the power grid structure (composed by three medium voltage branches) with the current power demands of the consumers of the island of Maio have a potential integration for 300 EVs if battery chargers with almost sinusoidal current consumption are used, i.e., 152 for the first medium voltage branch, 35 for the second branch, and 113 for the third branch. Moreover, the results show that the first medium voltage branch of the distribution system, which has the capability to support the integration of 152 EVs if the battery chargers have sinusoidal current consumption (presenting a maximum value of THDv % in the power grid voltage of 1.8 %), only can support 27 EVs if are used traditional battery chargers, with highly distorted current consumption (considering a maximum THDv % of 5 %).

Vitor Monteiro, M. J. Sepúlveda, J. C. Aparício Fernandes, J. G. Pinto, João L. Afonso
OpenADR—Intelligent Electrical Energy Consumption Towards Internet-of-Things

With the growing of irregular renewable energy sources, such as wind and solar, are required energy backup solutions to establish an advantageous compromise between the energy production and consumption. Typically, these renewable energy sources are not installed at the end-users level, which can create the problem of uncontrolled distributed energy sources. In this research work we propose a solution based on the standard OpenADR to handle this problem, creating a platform based on internet–of-things capable to turn-on or off electrical devices based on a central decision process that meets the requirements of energy producers and consumers. Producers can provide energy according to the consumer’s requirements and take part of energy production and costs fluctuations. Based on an OpenADR standard for energy data exchange and a central cloud server, a list of services are provided to handle this transactions, with georeferenced information to minimize energy losses in the distribution process.

João Ferreira, Hugo Martins, Manuel Barata, Vítor Monteiro, João L. Afonso

General Applications

Frontmatter
A Low-Cost ZigBee-Based Wireless Industrial Automation System

This paper describes the development of an industrial automation system based on a ZigBee wireless sensor network, designed for the monitoring and control of multiple refrigeration equipments in an industrial area, replacing the existing cabled network, which is based on the LonWorks platform. For this purpose, ZigBee routers were used to replace the local controllers at the refrigeration equipments, while the central management controller was replaced by a ZigBee coordinator and a PC. The proposed system was developed using a hardware platform based in the CC2530 integrated circuit and the Z-Stack software. Results from experimental field tests performed in an industrial environment are provided in order to assess the performance of the developed ZigBee network.

Pedro Castro, João L. Afonso, José A. Afonso
Comparative Analysis of Gain-Scheduled Wheel Slip Reset Controllers with Different Reset Strategies in Automotive Brake Systems

Wheel slip control bases its effectiveness on operating in the maximum adherence zone, guaranteeing the correct handling of the vehicle. The use of brake-by-wire systems and electromechanical actuators, make possible the control of each wheel slip independently, improving the performance of braking systems. Several controllers are proposed to enhance the overall effectiveness of the braking maneuver. To do this, several reset strategies are compared: reset control with zero crossing, fixed reset band and variable reset band. The improvements achieved proceed from the betterment of the outputs of the system such as the transient time and the overshooting. The robustness of the system to changes in the friction conditions is also improved by reset control and reset bands.

Miguel Cerdeira-Corujo, Adriana Costas, Emma Delgado, Antonio Barreiro
Design and Development of Control System for Railway Cable Laying

In this work is studied the automation of a railway cable laying system using a PLC as regulator, where the objective is to keep as stable as possible the stress of the cable being laid. As the system was completely manual, a previous work has been needed in order to set both sensors and actuators so that the system can be electrically controlled. Different tests were done in order to find out the relationship between the different variables, and to propose a regulator algorithm according to these. The obtained results show that the system is properly automated via PLC using the designed regulator.

Valentín Cañas, Andrés García, Javier de las Morenas, Jesús Blanco
Mobile Sensing System for Cycling Power Output Control

This paper describes the development of a novel cycling effort control system that contributes to promote the users’ physical health and mobility. This system controls the motor assistance level of an electric bicycle in order to ensure that the cyclist’s power output remains inside the desired limits, regardless of changes in variables such as the speed of the bicycle or the slope of the terrain. The power output is monitored using a sensor device that provides raw torque and cadence data, whereas a smartphone application processes these data, implements the effort control algorithm and provides the user interface. Modules on the bicycle handle the data acquisition, wireless communication with the smartphone and driving of the motor assistance level. Experimental results validate the effectiveness of the implemented power output control system.

José A. Afonso, Filipe J. Rodrigues, Delfim Pedrosa, João L. Afonso
Automatic Control of Madeira Wine Aging Process

Madeira wine aging processes are slow and costly. Besides, the value invested, the storage space, the energy costs and temperature control must also be considered. It has been shown that the aging process can include a heating step under controlled conditions, which can decrease the time necessary to achieve the characteristics of a typical fortified wine. The temperature control inside the tanks in the Madeira wine storage, mostly carried out manually, is the most important step to achieve a high quality wine. This work describes the procedure developed to implement, at low cost, an automatic temperature control inside the tanks in a pilot scale unit. Five different controllers were tested, where the Direct Inverse Control was the one that shows the best performance.

Carlos M. Faria, Darío Baptista, José Carlos Marques, Fernando Morgado-Dias
Study of Quality Service in AIS Gateway System

About 90 % of the volume of world trade is transported by sea via ships, this volume corresponds to about 70 % of world trade in value. Thus, maritime transport must be made on the basis of the highest rates of safety. Global distress communication systems, ship reporting systems, emergency radio beacons, and other technologies have greatly enhanced mariners’ safety. Considering this, the paper presents a platform that enables the maritime access information from data provided by the Automatic Identification System (AIS) in a quick way only by using your mobile phone. The developed and made available platform intended as a complement to any existing technology that supports shipping with high safety indices. In this paper the proposed approach is used in two real situations. The results make it possible to understand that the quality of service is good and it can provide relevant information for shipping management.

Mário Assunção, Luis Mendonça
Realization of PID Controllers in Analog Reconfigurable Hardware

This paper describes the implementation of PID controllers using FPAA/dpASP devices. Two typical plants usually found in industrial applications are used to test the controllers and the results are compared with those obtained with the software MATLAB. For the tuning of the PID controllers it is adopted the well-known Ziegler-Nichols heuristic rules. The effectiveness of the proposed reconfigurable technology is demonstrated by the good accordance between the simulation results and the FPAA/dpASP circuit responses.

Paulo J. R. Fonseca, Ramiro S. Barbosa
Speed Control of an Experimental Pneumatic Engine

Speed control of an experimental pneumatic engine is used to implement and compare performance of different controllers. Firstly, the system static characteristics and transfer functions are identified so that controllers can be tuned and simulations can be done. Secondly, feedback, cascade and model free controllers are tuned, simulated and implemented. Finally, the controllers performances are compared and conclusions are drawn.

João Pardelhas, Miguel Silva, Luis Mendonça, Luis Baptista
Design and Implementation of a PI Controller for a Metal Casting Machine

Control and monitoring systems capabilities are unavoidable to improve product quality, reduce production time, and to the rapid adaptation to changes in production. Therefore, it is advantageous to develop control and monitoring systems, and maximize the use of the resources already available in machine tools, without high additional costs and hard implementations. The use of Programmable Logic Controllers (PLC) on industries is growing. This sort of controller has been an election tool to attend present day requirements. It has the necessary resources to acquire and manage the information and control of the machines, and easily interacts with SCADA systems. The objective of the study described in this paper was to develop a solution for monitoring a metal casting machine, which could replace an outdated system installed on it, and find a solution to control a metal pouring process. All programs that allow the PLC to control the machine movements, and also perform the casting process, were developed during the project implementation. The results show that the developed solution is able to control the machine without the need to invest in a PC, which is a more expensive solution and with a more limited life time.

Bruno R. Mendes, Manuel F. Silva, Ramiro S. Barbosa

Education

Frontmatter
Control Engineering Learning by Integrating App-Inventor Based Experiments

This paper presents a teaching/learning experiment on the use of MITAppI2 as a friendly tool in Automation courses. The goal was to assess if the up-to-date mobile applications can act as promoters in learning automation topics. The experiment took place in two Portuguese universities. The results achieved point towards a successful use of these tools in university classes.

Filomena Soares, Paulo Moura Oliveira, Celina P. Leão
Inverted Pendulum Controlled by an Analog PID Controller: A Framework for a Laboratorial Experiment

This paper presents the design of a framework for a didactic kit for control studies based on a rotary inverted pendulum. One of the challenges was to involve students in the design of the platform. This first version of the kit was developed by students of the Integrated Master on Industrial Electronics and Computers Engineering at the University of Minho. It considers the design and implementation of the control of the angular position of an inverted pendulum through an analog Proportional, Integral and Derivative (PID) controller. This Single Input Single Output (SISO) control system allows retrieving the equilibrium position of the pendulum when it is subjected to disturbances.

Luís Dias, José Ferreira, Filomena Soares, Gil Lopes, João Sena Esteves, M. J. Sepúlveda, Paulo Garrido
Online Control of TOS1A Thermo-Optical Plant Using OpenModelica

The paper describes remote approach to the control of thermo-optical plant. The attention is devoted to the open solution that is based on the OpenModelica simulation environment. The plant enables to control two variables: temperature and light intensity. Both of them can be influenced by the user, using a graphical user interface via a web browser. The user can run both the open and the closed loop experiment, as well. In the second case the predefined PI controller and the own control algorithm can be used. The graphical presentation of plant variables is constantly updated via server-sent events.

Katarína Žáková
DC Motor Educational Kit: A Teaching Aid in Control Theory

This paper describes a laboratory control theory experiment supported by the use of a DC Motor Educational Kit. The impact, as a teaching aid, of the proposed laboratory control experiment is evaluated, having in mind the student’s feedback. The DC motor that is used in the developed educational Kit is the EMG30, being a low cost 12 V motor equipped with encoders and a 30:1 reduction gearbox. The experiment is based on real hardware and on simulation, using the SimTwo realistic simulation software. In order to implement the realistic simulation the EMG30 model was obtained. Students’ feedback was acquired using a questionnaire and the results confirmed the importance given to these practical experiments.

António Paulo Moreira, Paulo Costa, José Gonçalves, Brígida M. Faria
Metadata
Title
CONTROLO 2016
Editors
Paulo Garrido
Filomena Soares
António Paulo Moreira
Copyright Year
2017
Electronic ISBN
978-3-319-43671-5
Print ISBN
978-3-319-43670-8
DOI
https://doi.org/10.1007/978-3-319-43671-5