Percorrer por autor "Duarte, Fernando B. M."
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- 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.
- Chaos dynamics in the trajectory control of redundant manipulatorsPublication . Duarte, Fernando B. M.; Tenreiro Machado, J. A.Several kinematic control algorithms for redundant manipulators adopt generalized inverse matrices. In this line of thought, the generalized inverse control scheme is tested through experiments that reveal the difficulties that often arise. Motivated by these problems this paper studies kinematics and dynamics of the trajectory planning scheme. The experiment confirm the non-linear and chaotic performance of the algorithm and gives a deeper insight towards the future development of superior trajectory control systems.
- A chaos perspective in the trajectory control of redundant manipulatorsPublication . Duarte, Fernando B. M.; Tenreiro Machado, J. A.Several kinematic control algorithms for redundant manipulators adopt generalized inverse matrices. In this line of thought, the generalized inverse control scheme is tested through experiments that reveal the difficulties that often arise. Motivated by these problems this paper studies kinematics and dyanmics of trajectory planning scheme. The experiement confirm the non-linear and chaotic performance of the algorithm and gives a deeper insight towards the future development of superior trajectory control systems.
- Chaotic behavior in the pseudoinverse control of redundant and hyper-redundant robotsPublication . Duarte, Fernando B. M.; Tenreiro Machado, J. A.Several kinematic control algorithms for redundant manipulators adopt generalized inverse matrices. In this line of thought, the generalized inverse control scheme is tested through experiments that reveal the difficulties that often arise. The experiments confirm the non-linear and chaotic performance of the algorithm and give a deeper insigth towards the future development of superior trajectory control systems.
- Chaotic Phenomena and Fractional-Order Dynamics in the Trajectory Control of Redundant ManipulatorsPublication . Duarte, Fernando B. M.; Tenreiro Machado, J. A.Redundant manipulators have some advantages when compared with classicalarms because they allow the trajectory optimization, both on the freespace and on the presence of obstacles, and the resolution ofsingularities. For this type of arms the proposed kinematic controlalgorithms adopt generalized inverse matrices but, in general, thecorresponding trajectory planning schemes show important limitations.Motivated by these problems this paper studies the chaos revealed by thepseudoinverse-based trajectory planning algorithms, using the theory offractional calculus.
- Chaotic phenomena in the trajectory control of redundant manipulatorsPublication . Duarte, Fernando B. M.; Tenreiro Machado, J. A.Redundant manipulators have some advantages when compared with classical arms because they allow the trajectory optimization, both on the free space and on the presence of obstacles, and the resolution of singularities. For tihs type of manipulators, the proposed kinematic control algorithms adopt generalized inverse matrices. In this line of thought, the generalized inverse control scheme is tested through several experiments that reveal the difficulties that often arise. Motivated by these problems this paper studies the chaos revealed by the kinematics trajectory planning scheme, as well as its influence on the dynamics, when controlling redundant and hyper-redundant manipulators. The results reveal several fundamental properties of the chaotic phenomena and gives a deeper insight towards the future developement of superior trajectory control algorithms.
- Describing function of a simple mechanical system with non-linear frictionPublication . Duarte, Fernando B. M.; Tenreiro Machado, J. A.This paper studies the describing function (DF) of systems constituted by a mass subjected to nonlinear friction. The friction force is decomposed in two components namely, the viscous and the Coulomb friction. The system dynamics is analyzed in the DF perspective revealing a fractional-order behaviour. The reliability of the DF method is evaluated through the signal harmonic contents.
- Describing function of systems with nonlinear frictionPublication . Duarte, Fernando B. M.; Tenreiro Machado, J. A.This paper studies the describing function (DF) of systems composed of a mass subjected to nonlinear friction. The friction force is decomposed in three components namely, the viscous, the Coulomb and the static forces. The system dynamics is analyzed in the DF perspective and the reliability of the DF method is evaluated through the signal harmonic content.
- A fractional calculus perspective of mechanical systems modelingPublication . Barbosa, Ramiro; Duarte, Fernando B. M.; Tenreiro Machado, J. A.The area of fractional calculus (FC) goes back to the beginning of the theory of differential calculus. Nervertheless, the application of FC just emerged in the last two decades, due to the progress in the area of chaos that revealed subtle relationchips with the FC concepts. In the area of dynamical systems theory some work has been carried out but the proposed models and algorithms are still in a preliminary stage of stablishment. Having these ideas in mind, the paper discusses a FC perspective in the study of the dynamics and control of mechanical systems.
- Fractional dynamics in the describing function analysis of nonlinear frictionPublication . Duarte, Fernando B. M.; Tenreiro Machado, J. A.This paper studies the describing function (DF) of systems constituted by a mass subjected to nonlinear friction. The friction force is decomposed in three components namely, the viscous, the Coulomb and the static forces. The system dynamics is analyzed in the DF perspective revealing a fractional-order behaviour. The reliability of the DF method is evaluated through the signal harmonic content and the limit cycle prediction.
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