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Publicações

Publicações por Nuno Miguel Ferreira

2006

The cooperation of two manipulators with fractional controllers

Autores
Fonseca Ferreira, NM; Tenreiro Machado, JA; Boaventura Cunha, J;

Publicação
2006 IEEE International Conference on Computational Cybernetics, ICCC

Abstract
This paper analyzes the dynamics and the implementation of fractional-order algorithms in the position/force control of two robots holding an object. The experiments reveal that fractional algorithms lead to performances superior to classical integer-order controllers.

2004

Fractional-order position/force robot control

Autores
Ferreira, NMF; Machado, JAT; Cunha, JB;

Publicação
ICCC 2004: SECOND IEEE INTERNATIONAL CONFERENCE ON COMPUTATIONAL CYBERNETICS, PROCEEDINGS

Abstract
This paper presents the implementation of fractional-order algorithms both for hybrid and cascade position/force control of robotic manipulators. The system performance and robustness is analyzed in the time and frequency domains. The effects joint backlash and flexibility are also investigated.

2006

Fractional control of two arms working in cooperation

Autores
Fonseca Ferreira, NM; Tenreiro Machado, JA; Galhano, AMSF; Boaventura Cunha, J;

Publicação
IFAC Proceedings Volumes (IFAC-PapersOnline)

Abstract
This paper analyzes the performance of two cooperative robot manipulators. It is studied the implementation of fractional-order algorithms in the position/force control of two robots holding an object. The experiments reveal that fractional algorithms lead to performances superior to classical integer-order controllers.

2008

Automated Synthesis Procedure of RF Discrete Tuning Differential Capacitance Circuits

Autores
Mendes, L; Solteiro Pires, EJS; Vaz, JC; Rosario, MJ; de Moura Oliveira, PBD; Tenreiro Machado, JAT; Fonseca Ferreira, NMF;

Publicação
APMC: 2008 ASIA PACIFIC MICROWAVE CONFERENCE (APMC 2008), VOLS 1-5

Abstract

2008

Single-objective front optimization: application to rf circuit design

Autores
Pires, EJS; Machado, JAT; Mendes, L; Ferreira, NMF; De Moura Oliveira, PB; Vaz, J; Rosario, M;

Publicação
Genetic and Evolutionary Computation Conference, GECCO 2008, Proceedings, Atlanta, GA, USA, July 12-16, 2008

Abstract
This paper proposes a new algorithm which promotes well distributed non-dominated fronts in the parameters space when a single-objective function is optimized. This algorithm is based on e-dominance concept and maxmin sorting scheme. Besides that, the paper also presents the results of the algorithm when it is used in the automated synthesis of optimum performance CMOS radio-frequency and microwave binary-weighted differential switched capacitor arrays (RFDSCAs). The genetic synthesis tool optimizes a fitness function which is based on the performance parameter of the RFDSCAs. To validate the proposed design methodology, a CMOS RFDSCA is synthesized, using a 0.25 µm BiCMOS technology.

2009

Design Optimization of Radio Frequency Discrete Tuning Varactors

Autores
Mendes, L; Solteiro Pires, EJS; de Moura Oliveira, PBD; Tenreiro Machado, JAT; Fonseca Ferreira, NMF; Vaz, JC; Rosario, MJ;

Publicação
APPLICATIONS OF EVOLUTIONARY COMPUTING, PROCEEDINGS

Abstract
This work presents a procedure to automate the design of Si-integrated radio frequency (RF) discrete tuning varactors (RFDTVs). The synthesis method, which is based on evolutionary algorithms, searches for optimum performance RF switched capacitor array circuits that fulfill the design restrictions. The design algorithm uses the c-dominance concept and the maximin sorting scheme to provide a set of different Solutions (circuits) well distributed along an optimal front in the parameter space (circuit size and component values). Since all the solutions present the same performance, the designer call Select the circuit that is best suited to be implemented in a particular integration technology. To assess the performance of the synthesis procedure, several RFDTV circuits, provided by the algorithm, were designed and simulated rising a 0.18 mu m CMOS technology and the Cadence Virtuoso Design Platform. The comparisons between the algorithm and circuit; simulation results show that they are very close, pointing out that; the proposed design procedure is a powerful design tool.

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