Percorrer por autor "Barbosa, Ramiro"
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- Analysis of Fractional-Order Discrete Controllers in the Presence of NonlinearitiesPublication . Barbosa, Ramiro; Tenreiro Machado, J. A.; Galhano, AlexandraPresently, the development of fractional-order controllers is one of the most promising fields of research. However, most of the work in this area addresses the case of linear systems. In this paper we consider the analysis of fractional-order control of nonlinear systems. The performance of discrete fractional-order controllers in the presence of several nonlinearities is discussed. Some results are provided that assesses the superior robustness of such algorithms.
- Application of Fractional Calculus in Control and ElectromagnetismPublication . Tenreiro Machado, J. A.; Barbosa, Ramiro; Jesus, Isabel S.; Silva, Manuel; Reis, Cecília; Figueiredo, LinoThis 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.
- Application of Fractional Calculus in EngineeringPublication . Machado, J. A. Tenreiro; Jesus, Isabel S.; Barbosa, Ramiro; Silva, Manuel; Reis, CecíliaFractional Calculus (FC) goes back to the beginning of the theory of differential calculus. Nevertheless, the application of FC just emerged in the last two decades. It has been recognized the advantageous use of this mathematical tool in the modelling and control of many dynamical systems. Having these ideas in mind, this paper discusses a FC perspective in the study of the dynamics and control of several systems. The paper investigates the use of FC in the fields of controller tuning, legged robots, electrical systems and digital circuit synthesis.
- Application of Fractional Calculus in Genetic Algorithms, Transportation Systems and RoboticsPublication . Tenreiro Machado, J. A.; Silva, Manuel; Reis, Cecília; Figueiredo, Lino; Barbosa, Ramiro; Jesus, Isabel S.This article illustrates several applications of fractional calculus (FC). This paper investigates the use of FC in circuit synthesis, traffic systems and robot control.
- Application of fractional calculus in the control of mechanical systemsPublication . Tenreiro Machado, J. A.; Barbosa, Ramiro; Duarte, Fernando B. M.; Ferreira, Nuno M. F.The Fractional Calculus (FC) goes back to the begining of the theory of differential calculus. Nevertheless, the application of FC just emerged in the last two decades, due to the progress in the area of chaos that revelead subtle relationships with the FC concepts. In the field of dynamical systems theory some work has been carried out but the proposed models and algorithms are still in a preliminary stage of establishment. Having these ideas in mind, the paper discusses a FC perspective in the study of the dynamics and control of mechanical systems.
- Application of fractional calculus in the system modelling and controlPublication . Tenreiro Machado, J. A.; Barbosa, Ramiro; Silva, Manuel; Figueiredo, Lino; Jesus, Isabel S.; Galhano, AlexandraFractional Calculus (FC) goes back to the beginning of the theory of differential calculus. Nevertheless, the application of FC just emerged in the last two decades, due to the progress in the area of chaos that revealed subtle relationships with the FC concepts. In the field of dynamical systems theory some work has been carried out but the proposed models and algorithms are still in a preliminary stage of establishment. Having these ideas in mind, the paper discusses a FC perspective in the study of the dynamics and control of several systems.
- Applications of fractional calculus in electrical and computer engineeringPublication . Tenreiro Machado, J. A.; Silva, Manuel; Barbosa, Ramiro; Jesus, Isabel S.; Reis, Cecília; Marcos, Maria da Graça; M. Afonso, Luís; Lima, Miguel F. M.; Pires, E. J. Solteiro; Ferreira, N. M. FonsecaFractional Calculus (FC) goes back to the beginning of the theory of differential calculus. Nevertheless, the application of FC just emerged in the last two decades, due to the progress in the area of chaos that revealed subtle relationships with the FC concepts. In the field of dynamical systems theory some work has been carried out but the proposed models and algorithms are still in a preliminary stage of establishment. Having these ideas in mind, the paper discusses a FC perspective in the study of the dynamics and control of several systems. This article illustrates several applications of fractional calculus in science and 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 the fields of controller tuning, electrical systems, digital circuit synthesis, evolutionary computing, redundant robots, legged robots, robotic manipulators, nonlinear friction and financial modeling.
- Commande d'ordre fractionnaire position/force d'un manipulateur mécaniquePublication . Tenreiro Machado, J. A.; Barbosa, Ramiro; Ferreira, N. M.Cet article étudie l'implementation d'algorithmes d'ordres fractionnaires pour la commande hybride position/force de robots manipulateurs. Les performances du système snt analysées en termes de temps de réponse et de robustesse. Une comparaison avec une stratégie de commande basée sur des algorithmes de type PID est également effectuée. Par ailleurs, des phénomènes non linéaires issus de joints tels que les frottements, les jeux de transmission dynamiques et la flexibilité non linéaires sont étudiés.
- Comparison of Different Fractional Order PD0.5 Control Algorithm Implementations for Legged RobotsPublication . Silva, Manuel; Tenreiro Machado, J. A.; Barbosa, RamiroThis paper studies different Fractional Order (FO) PD0.5 algorithms applied to the leg joint control of a hexapod robot with two dof legs. For the implementation of the FO PD0.5 joint controllers both the Padé and the series approximations are considered, being compared their performance. For simulation purposes the robot prescribed motion is characterized through several locomotion variables and parameters and for the walking performance evaluation two indices are used, one of them based on the mean absolute density of energy per travelled distance and the other one on the hip trajectory errors. A set of simulation experiments reveals the influence of the different approximations and the order of the PD0.5 controllers tuning upon the proposed indices.
- Comparison of different orders padé fractional order PD0.5 control algorithm implementationsPublication . Silva, Manuel; Tenreiro Machado, J. A.; Barbosa, RamiroThis paper studies the performance of different order Padé Fractional Order (FO) PD0.5 controllers applied to the leg joint control of a hexapod robot with two dof legs and joint actuators with saturation. For simulation purposes the robot prescribed motion is characterized through several locomotion variables and for the walking performance evaluation are used two indices, one based on the mean absolute density of energy per travelled distance and the other on the hip trajectory errors. A set of simulation experiments reveals the influence of the different order Padé PD0.5 controllers tuning upon the proposed indices.