2008
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
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
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
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
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.
2008
Authors
Veiga, G; Pires, JN;
Publication
ICINCO 2008: PROCEEDINGS OF THE FIFTH INTERNATIONAL CONFERENCE ON INFORMATICS IN CONTROL, AUTOMATION AND ROBOTICS, VOL RA-2: ROBOTICS AND AUTOMATION, VOL 2
Abstract
Programming industrial robotic workcells is a challenging task, namely because it means dealing with several types of machines, mange the data flow between them and orchestrate their basic functionality into a working program. In this work service oriented architectures are used for the task of programming robotic workcells along with managing the communication between cell components, and a statechart model engine is implemented to orchestrate the system logic. The objective of this paper is to focus in merging service oriented architectures with StateCharts XML, and in evaluating that robotic workcell programming approach using a simple laboratory test bed.
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