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Publications

Publications by CRIIS

2008

Research issues in biological inspired sensors for flying robots

Authors
Silva, MF; Machado, JAT; Jesus, IS;

Publication
Proceedings of the IASTED International Conference on Modelling, Identification, and Control, MIC

Abstract
Biological inspired robotics is an area experiencing an increasing research and development. In spite of all the recent engineering advances, robots still lack capabilities with respect to agility, adaptability, intelligent sensing, fault-tolerance, stealth, and utilization of in-situ resources for power when compared to biological organisms. The general premise of bio-inspired engineering is to distill the principles incorporated in successful, nature-tested mechanisms of selected features and functional behaviors that can be captured through biomechatronic designs and minimalist operation principles from nature success strategies. Based on these concepts, robotics researchers are interested in gaining an understanding of the sensory aspects that would be required to mimic nature design with engineering solutions. In this paper are analysed developments in this area and the research aspects that have to be further studied are discussed.

2008

Discretization of complex-order algorithms for control applications

Authors
Barbosa, RS; Machado, JAT; Silva, MF;

Publication
JOURNAL OF VIBRATION AND CONTROL

Abstract
In this article we describe several methods for the discretization of the differintegral operator s(a), where alpha = u + jv is a complex value. The concept of the conjugated-order differintegral is also introduced, which enables the use of complex-order differintegrals while still producing real-valued time responses and transfer functions. The performance of the resulting approximations is analysed in both the time and frequency domains. Several results are presented that demonstrate its utility in control system design.

2008

A Survey of Technologies for climbing robots adhesion to surfaces

Authors
Silva, MF; Tenreiro Machado, JA; Tar, JK;

Publication
ICCC 2008 - IEEE 6th International Conference on Computational Cybernetics, Proceedings

Abstract
Climbing robots are being developed for applications ranging from cleaning to inspection of difficult to reach constructions. These machines should be capable of travelling on different types of surfaces (such as floors, walls, ceilings) and to walk between such surfaces. Furthermore, these machines should adapt and reconfigure for various environment conditions and should be self-contained. Regarding the adhesion to the surface, they should be able to produce a secure gripping force using a light-weight mechanism. Bearing these facts in mind, this paper presents a survey of different technologies used for climbing robots adhesion to surfaces. © 2008 IEEE.

2008

Climbing robots: A survey of technologies and applications

Authors
Silva, MF; Machado, JAT;

Publication
Advances in Mobile Robotics - Proceedings of the 11th International Conference on Climbing and Walking Robots and the Support Technologies for Mobile Machines, CLAWAR 2008

Abstract
The interest in the development of climbing robots is growing rapidly. Motivations are typically to increase the operation efficiency by obviating the costly assembly of scaffolding or to protect human health and safety in hazardous tasks. Climbing robots are starting to be developed for applications ranging from cleaning to inspection of difficult to reach constructions. These robots should be capable of travelling on different types of surfaces, with varying inclinations, such as floors, walls, ceilings, and to walk between such surfaces. Furthermore, these machines should be capable of adapting and reconfiguring for various environment conditions and to be self-contained. Regarding the adhesion to the surface, they should be able to produce a secure gripping force using a light-weight mechanism. This paper presents a survey of different applications and technologies proposed for the implementation of climbing robots. Copyright © 2008 by World Scientific Publishing Co. Pte. Ltd.

2008

Fractional order capacitors

Authors
Jesus, IS; Machado, JAT; Silva, MF;

Publication
Proceedings of the IASTED International Conference on Modelling, Identification, and Control, MIC

Abstract
The performance of electrical devices, depending on the processes of the electrolytes, have been fully described and the physical origin of each parameter is well established. However, the influence of the irregularity of the electrodes was not a subject of study and only recently, this problem became relevant in the viewpoint of fractional calculus. This paper describes an electrolytic process in the perspective of fractional order capacitors. In this line of thought, are developed several experiments for measuring the electrical impedance of the devices. The results are analyzed through the frequency response, revealing capacitances of fractional order that can constitute an alternative to the classical integer order elements.

2008

Using fractional derivatives in joint control of hexapod robots

Authors
Silva, MF; Machado, JAT; Barbosa, RS;

Publication
JOURNAL OF VIBRATION AND CONTROL

Abstract
This article studies several Fractional Order Control algorithms used for joint control of a hexapod robot. Both Pade and series approximations to the fractional derivative are considered for the control algorithm. The walking performance is evaluated through two indices: The mean absolute density of energy used per unit distance travelled, and the control effort. A set of simulation experiments reveals the influence of the different approximations upon the proposed indices. The results show that the fractional proportional and derivative algorithm, implemented using the Pade approximation with a small number of terms, gives the best results.

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