2008
Autores
Silva, MF; Machado, JAT;
Publicação
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
Autores
Jesus, IS; Machado, JAT; Silva, MF;
Publicação
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
Autores
Silva, MF; Machado, JAT; Barbosa, RS;
Publicação
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
Autores
Veiga, G; Pires, JN;
Publicação
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.
2008
Autores
Ziparo, VA; Locchi, L; Nardi, D; Palamara, RR; Costelha, H;
Publicação
Proceedings of the International Joint Conference on Autonomous Agents and Multiagent Systems, AAMAS
Abstract
The aim of this paper is to describe a novel representation framework for high level robot and multi-robot programming, called Petri Net Plans (PNP), that allows for representing all the action features that are needed for describing complex plans in dynamic environments. We provide a sound and complete execution algorithm for PNPs based on the semantics of Petri nets. Moreover, we show that multi-robot PNPs allow for a sound and complete distributed execution algorithm, given that a reliable communication channel is provided. PNPs have been used for describing effective plans for actual robotic agents which inhabit dynamic, partially observable and unpredictable environments, and experimented in different application scenarios. Copyright
2008
Autores
Costelha, H; Lima, P;
Publicação
Proceedings of the International Joint Conference on Autonomous Agents and Multiagent Systems, AAMAS
Abstract
This paper introduces Petri net (PN) based models of cooperative robotic tasks, namely those involving the coordination of two or more robots, thus requiring the exchange of synchronisation messages, either using explicit (e.g., wireless) or implicit (e.g., vision-based observation of teammates) communication. In the models, PN places represent primitive actions, subtasks and predicates set by sensor readings and communicated messages. Events are associated to PN transitions. The PN models can be used for task planning, plan execution and plan analysis. Different PN views enable the analysis of different properties. In this work we focus on plan analysis, namely on properties such as boundedness and liveness, corresponding to checking if resources usage is stable and plans have no deadlocks, as well as on stochastic performance, concerning the plan success probability. One novel feature of our work is that the analysis consists of composing several small action PN models with environment PN models, leading to a closed loop robot team/environment analysis methodology. Examples of application to simulated robotic soccer scenarios are presented. Copyright
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