Isabel Jesus | Instituto Politecnico do Porto (original) (raw)

Papers by Isabel Jesus

Research paper thumbnail of Fractional order dynamics in classical electromagnetic phenomena

The Maxwell equations play a fundamental role in the well established formulation of the electrom... more The Maxwell equations play a fundamental role in the well established formulation of the electromagnetic theory. These equations lead to the derivation of precise mathematical models useful in many applications in physics and engineering. The Maxwell equations involve only the integer-order calculus and, therefore, it is natural that the resulting classical models adopted in electrical engineering reflect this perspective. Recently, a closer look of some phenomena present in electrical systems, such as motors, transformers and lines, and the motivation towards the development of comprehensive models, seem to point out the requirement for a fractional calculus approach. Bearing these ideas in mind, in this study we shall address the well-known 'skin effect' and we reevaluate the results demonstrating its fractional-order dynamics.

Research paper thumbnail of Sistemas Fraccion��rios

Research paper thumbnail of Application of Fractional Calculus in Genetic Algorithms, Transportation Systems and Robotics

ave.dee.isep.ipp.pt

Department of Electrotechnical Engineering, Institute of Engineering of Porto Rua Dr. António Ber... more Department of Electrotechnical Engineering, Institute of Engineering of Porto Rua Dr. António Bernardino de Almeida, 4200-072 Porto, Portugal E-mail: {jtm, mss, cmr, lbf, rsb, isj}@isep.ipp.pt ... This article illustrates several applications of fractional calculus (FC). ...

Research paper thumbnail of Implementing an electrical fractional potential through a genetic algorithm

Several phenomena present in electrical systems, motivated the development of comprehensive model... more Several phenomena present in electrical systems, motivated the development of comprehensive models based on the theory of fractional calculus (FC). Bearing these ideas in mind, in this work, are applied the FC concepts to define, and to evaluate, the electrical potential of fractional order based in a genetic algorithm optimization scheme. Research on the approximation feasibility and convergence is also developed.N/

Research paper thumbnail of Fractional Order Dynamics in a Particle Swarm Optimization Algorithm

Seventh International Conference on Intelligent Systems Design and Applications (ISDA 2007), 2007

Although many mathematicians have searched on the fractional calculus since many years ago, its a... more Although many mathematicians have searched on the fractional calculus since many years ago, its application in engineering, especially in modeling and control, does not have many antecedents. Since there is much freedom in choosing the order of differentiator and integrator in fractional calculus, it is possible to model the physical systems accurately. This paper deals with the time-domain identification fractional-order chaotic systems, where conventional derivation is replaced by a fractional one with the help of a non-integer derivation. This operator is itself approximated by an N-dimensional system composed of an integrator and a phase-lead filter. A hybrid particle swarm optimization (PSO)-genetic algorithm (GA) method is applied to estimate the parameters of the approximated non-linear fractional-order chaotic system modeled by a statespace representation. The feasibility of this approach is demonstrated through identifying the parameters of the approximated fractional-order Lorenz chaotic system. The performance of the proposed algorithm is compared with GA and standard particle swarm optimization (SPSO) in terms of parameter accuracy and cost function. In order to evaluate the identification accuracy, the time-domain output error is designed as the fitness function for parameter optimization. The simulation results show that the proposed method is more successful than the other algorithms for parameter identification of the fractional-order chaotic systems.

Research paper thumbnail of Application of PSO Algorithm for the Study of Fractional Order Electrical Potential

Proceedings of the 18th IFAC World Congress, 2011

Particle swarm optimization (PSO) is a novel population based metaheuristic, inspired by social b... more Particle swarm optimization (PSO) is a novel population based metaheuristic, inspired by social behavior of bird flocking or fish schooling. It has the better ability of global searching and has been successfully applied in many areas of engineering and science. A fresh look of several phenomena present in electrical systems induced an approach based in the fractional calculus (FC) viewpoint. The problem of point multipoles of electric charges and the corresponding electrical potential is an important subject in the field of electromagnetism. In this work, we apply FC concepts to define, and to evaluate, the electrical potential of fractional order. For that, the analysis and the synthesis of fractional-order multipoles, based in a PSO optimization scheme, is addressed.

Research paper thumbnail of Research issues in intelligent transportation systems

Proc. of the European …, 2001

... Mapa do Campus. Research Issues on Intelligent Transportation Systems. Artigo em Livro de Act... more ... Mapa do Campus. Research Issues on Intelligent Transportation Systems. Artigo em Livro de Actas de Conferência Internacional. Autores: Lino Figueiredo Isabel Jesus José Tenreiro Machado José Rui da Rocha Pinto Ferreira Jorge Martins de Carvalho. Idioma: Português. ...

Research paper thumbnail of Analysis of a Traditional and a Fuzzy Logic Enhanced Perturb and Observe Algorithm for the MPPT of a Photovoltaic System

Algorithms

This paper presents the results obtained for the maximum power point tracking (MPPT) technique ap... more This paper presents the results obtained for the maximum power point tracking (MPPT) technique applied to a photovoltaic (PV) system, composed of five solar panels in series using two different methodologies. First, we considered a traditional Perturb and Observe (P&O) algorithm and in a second stage we applied a Fuzzy Logic Controller (FLC) that uses fuzzy logic concepts to improve the traditional P&O; both were implemented in a boost converter. The main aim of this paper is to study if an artificial intelligence (AI) based MPPT method, can be more efficient, stable and adaptable than a traditional MPPT method, in varying environment conditions, namely solar irradiation and/or environment temperature and also to analyze their behaviour in steady state conditions. The proposed FLC with a rule base collection of 25 rules outperformed the controller using the traditional P&O algorithm due to its adaptative step size, enabling the FLC to adapt the PV system faster to changing environme...

Research paper thumbnail of Fractional Order Dynamics in a Particle Swarm Optimization Algorithm

Seventh International Conference on Intelligent Systems Design and Applications (ISDA 2007), 2007

... JA Tenreiro Machado, Isabel S. Jesus Eng. ... In PJ Angeline, Z. Michalewicz, M. Schoe-nauer,... more ... JA Tenreiro Machado, Isabel S. Jesus Eng. ... In PJ Angeline, Z. Michalewicz, M. Schoe-nauer, X. Yao, and A. Zalzala, editors, Proceedings of the Congress of Evolutionary Computation, volume 3, pages 1945–1950, Mayflower Hotel, Washington DC, USA, 6-9 July 1999. ...

Research paper thumbnail of Sistemas inteligentes de transporte

Research paper thumbnail of Using a PSO algorithm for tuning a PID controller applied to a heat system

In this paper we study the control of a heat diffusion system in the perspective of fractional co... more In this paper we study the control of a heat diffusion system in the perspective of fractional control and using a particle swarm optimization (PSO) algorithm. PSO is one of the latest evolutionary optimization techniques, inspired by social behavior of bird flocking or fish schooling. It has the better ability of global searching and has been successfully applied in many areas of engineering and science. Simulations are presented assessing the performance of the proposed fractional algorithms.

Research paper thumbnail of Fuzzy reasoning in fractional-order PD controllers

Proceedings of the 10th Wseas International Conference on Applied Informatics and Communications and 3rd Wseas International Conference on Biomedical Electronics and Biomedical Informatics, Aug 20, 2010

In this paper, we incorporate fuzzy reasoning in fractional-order PD controllers. The resulting f... more In this paper, we incorporate fuzzy reasoning in fractional-order PD controllers. The resulting fuzzy fractional PD controller is investigated in terms of its digital implementation and robustness. The combined features of both algorithms will result in a better control system performance. Also, the effectiveness and robustness of the new methodology is illustrated through an application example.

Research paper thumbnail of Control of a heat diffusion system through a fractional order nonlinear algorithm

Comput Math Appl, 2010

The concept of differentiation and integration to non-integer order has its origins in the sevent... more The concept of differentiation and integration to non-integer order has its origins in the seventeen century. However, only in the second-half of the twenty century appeared the first applications related to the area of control theory. In this paper we consider the study of a heat diffusion system based on the application of the fractional calculus concepts. In this perspective, several control methodologies are investigated and compared. Simulations are presented assessing the performance of the proposed fractional-order algorithms.

Research paper thumbnail of Modelling and Simulation of Walking Robots with 3 dof Legs

... the ith leg lengths Li1 and Li2, the ith foot length Li3 and the foot trajectory offset Oi (i... more ... the ith leg lengths Li1 and Li2, the ith foot length Li3 and the foot trajectory offset Oi (i = 1, …, n). When the robot leg is equipped with a foot (ie, the robot has three dof legs), there is the need to consider an additional variable, namely the value of the desired angle between the ...

Research paper thumbnail of Modeling and simulation of walking robots with 3 dof legs

This paper describes a simulation model for a multilegged locomotion system with 3 dof legs and l... more This paper describes a simulation model for a multilegged locomotion system with 3 dof legs and leg joint actuators having saturation. For that objective the robot prescribed motion is characterized in terms of several locomotion variables. Moreover, the robot body is divided into several segments in order to emulate the behavior of an animal spine. A non-linear spring-dashpot system models the foot-ground interaction, being its parameters computed from studies on soil mechanics. To conclude, the performance of the developed model is evaluated through a set of experiments while the robot leg joints are controlled using a proportional and derivative algorithm.

Research paper thumbnail of Fractional Modelling of the Electrical Conduction in Nacl Electrolyte

The fractional calculus (FC) constitutes a mathematical tool that presently is being applied in m... more The fractional calculus (FC) constitutes a mathematical tool that presently is being applied in many emerging scientific areas, such as electricity, magnetism, mechanics, fluid dynamics and medicine. This paper describes the use of an electrolytic process for developing fractional order capacitors. The study includes several experiments for measuring the electrical impedance of the devices. The results are analyzed through the frequency response revealing capacitances of fractional order.

Research paper thumbnail of A suggestion from the past?

Fractional Calculus and Applied Analysis

The generalization of the concept of derivative to non-integer values goes back to the beginning ... more The generalization of the concept of derivative to non-integer values goes back to the beginning of the theory of differential calculus. Nevertheless, its application in physics and engineering remained unexplored up to the last two decades. Recent research motivated the establishment of strategies taking advantage of the Fractional Calculus (FC) in the modeling and control of many phenomena. In fact, many classical engineering applications deserve a closer attention and a new analysis in the viewpoint of FC. Bearing these ideas in mind, this work addresses the partial differential equations that model the electrical transmission lines. The distributed characteristics of this system may lead to design techniques, for integrated circuits, capable of implementing directly fractional-order impedances and, therefore, constitutes an alternative to exploring fractal geometries and dielectric properties.

Research paper thumbnail of Application of Fractional Calculus in the Control of Heat Systems

Journal of Advanced Computational Intelligence and Intelligent Informatics

This article illustrates two applications of fractional calculus (FC) in engineering. It has been... more This article illustrates two applications of fractional calculus (FC) in engineering. It has been recognized the advantageous use of this mathematical tool in the modeling and control of many dynamical systems. In this perspective, this paper investigates the use of FC in PID tuning and electrical potential.

Research paper thumbnail of An evolutionary approach for the synthesis of fractional potentials

Fractional Calculus and Applied Analysis

Research paper thumbnail of On the Fractional PID Control of a Laboratory Servo System

In this paper are investigated several types of fractional-order PID controllers in the velocity ... more In this paper are investigated several types of fractional-order PID controllers in the velocity control of a servo system. The fractional controller is more flexible and gives the possibility of adjusting carefully the dynamical properties of a control system. The servo system is controlled by using a real-time digital control system based on MATLAB/Simulink. Results are compared with those obtained from classical PID controllers. Experimental responses are presented and analyzed, showing the effectiveness of the proposed fractional-order algorithms.

Research paper thumbnail of Fractional order dynamics in classical electromagnetic phenomena

The Maxwell equations play a fundamental role in the well established formulation of the electrom... more The Maxwell equations play a fundamental role in the well established formulation of the electromagnetic theory. These equations lead to the derivation of precise mathematical models useful in many applications in physics and engineering. The Maxwell equations involve only the integer-order calculus and, therefore, it is natural that the resulting classical models adopted in electrical engineering reflect this perspective. Recently, a closer look of some phenomena present in electrical systems, such as motors, transformers and lines, and the motivation towards the development of comprehensive models, seem to point out the requirement for a fractional calculus approach. Bearing these ideas in mind, in this study we shall address the well-known 'skin effect' and we reevaluate the results demonstrating its fractional-order dynamics.

Research paper thumbnail of Sistemas Fraccion��rios

Research paper thumbnail of Application of Fractional Calculus in Genetic Algorithms, Transportation Systems and Robotics

ave.dee.isep.ipp.pt

Department of Electrotechnical Engineering, Institute of Engineering of Porto Rua Dr. António Ber... more Department of Electrotechnical Engineering, Institute of Engineering of Porto Rua Dr. António Bernardino de Almeida, 4200-072 Porto, Portugal E-mail: {jtm, mss, cmr, lbf, rsb, isj}@isep.ipp.pt ... This article illustrates several applications of fractional calculus (FC). ...

Research paper thumbnail of Implementing an electrical fractional potential through a genetic algorithm

Several phenomena present in electrical systems, motivated the development of comprehensive model... more Several phenomena present in electrical systems, motivated the development of comprehensive models based on the theory of fractional calculus (FC). Bearing these ideas in mind, in this work, are applied the FC concepts to define, and to evaluate, the electrical potential of fractional order based in a genetic algorithm optimization scheme. Research on the approximation feasibility and convergence is also developed.N/

Research paper thumbnail of Fractional Order Dynamics in a Particle Swarm Optimization Algorithm

Seventh International Conference on Intelligent Systems Design and Applications (ISDA 2007), 2007

Although many mathematicians have searched on the fractional calculus since many years ago, its a... more Although many mathematicians have searched on the fractional calculus since many years ago, its application in engineering, especially in modeling and control, does not have many antecedents. Since there is much freedom in choosing the order of differentiator and integrator in fractional calculus, it is possible to model the physical systems accurately. This paper deals with the time-domain identification fractional-order chaotic systems, where conventional derivation is replaced by a fractional one with the help of a non-integer derivation. This operator is itself approximated by an N-dimensional system composed of an integrator and a phase-lead filter. A hybrid particle swarm optimization (PSO)-genetic algorithm (GA) method is applied to estimate the parameters of the approximated non-linear fractional-order chaotic system modeled by a statespace representation. The feasibility of this approach is demonstrated through identifying the parameters of the approximated fractional-order Lorenz chaotic system. The performance of the proposed algorithm is compared with GA and standard particle swarm optimization (SPSO) in terms of parameter accuracy and cost function. In order to evaluate the identification accuracy, the time-domain output error is designed as the fitness function for parameter optimization. The simulation results show that the proposed method is more successful than the other algorithms for parameter identification of the fractional-order chaotic systems.

Research paper thumbnail of Application of PSO Algorithm for the Study of Fractional Order Electrical Potential

Proceedings of the 18th IFAC World Congress, 2011

Particle swarm optimization (PSO) is a novel population based metaheuristic, inspired by social b... more Particle swarm optimization (PSO) is a novel population based metaheuristic, inspired by social behavior of bird flocking or fish schooling. It has the better ability of global searching and has been successfully applied in many areas of engineering and science. A fresh look of several phenomena present in electrical systems induced an approach based in the fractional calculus (FC) viewpoint. The problem of point multipoles of electric charges and the corresponding electrical potential is an important subject in the field of electromagnetism. In this work, we apply FC concepts to define, and to evaluate, the electrical potential of fractional order. For that, the analysis and the synthesis of fractional-order multipoles, based in a PSO optimization scheme, is addressed.

Research paper thumbnail of Research issues in intelligent transportation systems

Proc. of the European …, 2001

... Mapa do Campus. Research Issues on Intelligent Transportation Systems. Artigo em Livro de Act... more ... Mapa do Campus. Research Issues on Intelligent Transportation Systems. Artigo em Livro de Actas de Conferência Internacional. Autores: Lino Figueiredo Isabel Jesus José Tenreiro Machado José Rui da Rocha Pinto Ferreira Jorge Martins de Carvalho. Idioma: Português. ...

Research paper thumbnail of Analysis of a Traditional and a Fuzzy Logic Enhanced Perturb and Observe Algorithm for the MPPT of a Photovoltaic System

Algorithms

This paper presents the results obtained for the maximum power point tracking (MPPT) technique ap... more This paper presents the results obtained for the maximum power point tracking (MPPT) technique applied to a photovoltaic (PV) system, composed of five solar panels in series using two different methodologies. First, we considered a traditional Perturb and Observe (P&O) algorithm and in a second stage we applied a Fuzzy Logic Controller (FLC) that uses fuzzy logic concepts to improve the traditional P&O; both were implemented in a boost converter. The main aim of this paper is to study if an artificial intelligence (AI) based MPPT method, can be more efficient, stable and adaptable than a traditional MPPT method, in varying environment conditions, namely solar irradiation and/or environment temperature and also to analyze their behaviour in steady state conditions. The proposed FLC with a rule base collection of 25 rules outperformed the controller using the traditional P&O algorithm due to its adaptative step size, enabling the FLC to adapt the PV system faster to changing environme...

Research paper thumbnail of Fractional Order Dynamics in a Particle Swarm Optimization Algorithm

Seventh International Conference on Intelligent Systems Design and Applications (ISDA 2007), 2007

... JA Tenreiro Machado, Isabel S. Jesus Eng. ... In PJ Angeline, Z. Michalewicz, M. Schoe-nauer,... more ... JA Tenreiro Machado, Isabel S. Jesus Eng. ... In PJ Angeline, Z. Michalewicz, M. Schoe-nauer, X. Yao, and A. Zalzala, editors, Proceedings of the Congress of Evolutionary Computation, volume 3, pages 1945–1950, Mayflower Hotel, Washington DC, USA, 6-9 July 1999. ...

Research paper thumbnail of Sistemas inteligentes de transporte

Research paper thumbnail of Using a PSO algorithm for tuning a PID controller applied to a heat system

In this paper we study the control of a heat diffusion system in the perspective of fractional co... more In this paper we study the control of a heat diffusion system in the perspective of fractional control and using a particle swarm optimization (PSO) algorithm. PSO is one of the latest evolutionary optimization techniques, inspired by social behavior of bird flocking or fish schooling. It has the better ability of global searching and has been successfully applied in many areas of engineering and science. Simulations are presented assessing the performance of the proposed fractional algorithms.

Research paper thumbnail of Fuzzy reasoning in fractional-order PD controllers

Proceedings of the 10th Wseas International Conference on Applied Informatics and Communications and 3rd Wseas International Conference on Biomedical Electronics and Biomedical Informatics, Aug 20, 2010

In this paper, we incorporate fuzzy reasoning in fractional-order PD controllers. The resulting f... more In this paper, we incorporate fuzzy reasoning in fractional-order PD controllers. The resulting fuzzy fractional PD controller is investigated in terms of its digital implementation and robustness. The combined features of both algorithms will result in a better control system performance. Also, the effectiveness and robustness of the new methodology is illustrated through an application example.

Research paper thumbnail of Control of a heat diffusion system through a fractional order nonlinear algorithm

Comput Math Appl, 2010

The concept of differentiation and integration to non-integer order has its origins in the sevent... more The concept of differentiation and integration to non-integer order has its origins in the seventeen century. However, only in the second-half of the twenty century appeared the first applications related to the area of control theory. In this paper we consider the study of a heat diffusion system based on the application of the fractional calculus concepts. In this perspective, several control methodologies are investigated and compared. Simulations are presented assessing the performance of the proposed fractional-order algorithms.

Research paper thumbnail of Modelling and Simulation of Walking Robots with 3 dof Legs

... the ith leg lengths Li1 and Li2, the ith foot length Li3 and the foot trajectory offset Oi (i... more ... the ith leg lengths Li1 and Li2, the ith foot length Li3 and the foot trajectory offset Oi (i = 1, …, n). When the robot leg is equipped with a foot (ie, the robot has three dof legs), there is the need to consider an additional variable, namely the value of the desired angle between the ...

Research paper thumbnail of Modeling and simulation of walking robots with 3 dof legs

This paper describes a simulation model for a multilegged locomotion system with 3 dof legs and l... more This paper describes a simulation model for a multilegged locomotion system with 3 dof legs and leg joint actuators having saturation. For that objective the robot prescribed motion is characterized in terms of several locomotion variables. Moreover, the robot body is divided into several segments in order to emulate the behavior of an animal spine. A non-linear spring-dashpot system models the foot-ground interaction, being its parameters computed from studies on soil mechanics. To conclude, the performance of the developed model is evaluated through a set of experiments while the robot leg joints are controlled using a proportional and derivative algorithm.

Research paper thumbnail of Fractional Modelling of the Electrical Conduction in Nacl Electrolyte

The fractional calculus (FC) constitutes a mathematical tool that presently is being applied in m... more The fractional calculus (FC) constitutes a mathematical tool that presently is being applied in many emerging scientific areas, such as electricity, magnetism, mechanics, fluid dynamics and medicine. This paper describes the use of an electrolytic process for developing fractional order capacitors. The study includes several experiments for measuring the electrical impedance of the devices. The results are analyzed through the frequency response revealing capacitances of fractional order.

Research paper thumbnail of A suggestion from the past?

Fractional Calculus and Applied Analysis

The generalization of the concept of derivative to non-integer values goes back to the beginning ... more The generalization of the concept of derivative to non-integer values goes back to the beginning of the theory of differential calculus. Nevertheless, its application in physics and engineering remained unexplored up to the last two decades. Recent research motivated the establishment of strategies taking advantage of the Fractional Calculus (FC) in the modeling and control of many phenomena. In fact, many classical engineering applications deserve a closer attention and a new analysis in the viewpoint of FC. Bearing these ideas in mind, this work addresses the partial differential equations that model the electrical transmission lines. The distributed characteristics of this system may lead to design techniques, for integrated circuits, capable of implementing directly fractional-order impedances and, therefore, constitutes an alternative to exploring fractal geometries and dielectric properties.

Research paper thumbnail of Application of Fractional Calculus in the Control of Heat Systems

Journal of Advanced Computational Intelligence and Intelligent Informatics

This article illustrates two applications of fractional calculus (FC) in engineering. It has been... more This article illustrates two applications of fractional calculus (FC) in engineering. It has been recognized the advantageous use of this mathematical tool in the modeling and control of many dynamical systems. In this perspective, this paper investigates the use of FC in PID tuning and electrical potential.

Research paper thumbnail of An evolutionary approach for the synthesis of fractional potentials

Fractional Calculus and Applied Analysis

Research paper thumbnail of On the Fractional PID Control of a Laboratory Servo System

In this paper are investigated several types of fractional-order PID controllers in the velocity ... more In this paper are investigated several types of fractional-order PID controllers in the velocity control of a servo system. The fractional controller is more flexible and gives the possibility of adjusting carefully the dynamical properties of a control system. The servo system is controlled by using a real-time digital control system based on MATLAB/Simulink. Results are compared with those obtained from classical PID controllers. Experimental responses are presented and analyzed, showing the effectiveness of the proposed fractional-order algorithms.