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Publicações

Publicações por CRIIS

2009

Concept and design of the intellwheels platform for developing intelligent wheelchairs

Autores
Braga, RAM; Petry, M; Moreira, AP; Reis, LP;

Publicação
Lecture Notes in Electrical Engineering

Abstract
Many people with severe disabilities find it difficult or even impossible to use traditional powered wheelchairs independently by manually controlling these electrical devices. Intelligent wheelchairs are a very good solution to assist severely handicapped people who are unable to operate classical electrical wheelchair by themselves in their daily activities. This paper describes a development platform for intelligent wheelchairs called IntellWheels. The intelligent system developed may be added to commercial powered wheelchairs with minimal modifications in a very straightforward manner. The paper describes the concept and design of the platform, including the hardware and software, multimodal input interface and the intelligent wheelchair prototype developed to validate the approach. Preliminary results concerning automatic movement of the IntellWheels prototype are also described showing the autonomous movement capabilities of the prototype. © 2009 Springer-Verlag Berlin Heidelberg.

2009

Tuning and Application of Integer and Fractional Order PID Controllers

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

Publicação
Intelligent Engineering Systems and Computational Cybernetics

Abstract

2009

Control and dynamics of fractional order systems

Autores
Tenreiro Machado, JA; Jesus, IS; Barbosa, RS; Silva, MF;

Publicação
Studies in Computational Intelligence

Abstract
Fractional Calculus (FC) goes back to the beginning 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 nonlinear dynamics. This article discusses several applications of fractional calculus in science and engineering, namely: the control of heat systems, the tuning of PID controllers based on fractional calculus concepts and the dynamics in hexapod locomotion. © 2009 Springer-Verlag Berlin Heidelberg.

2009

Development of a genetic algorithm for the optimization of hexapod robot parameters

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

Publicação
Proceedings of the IASTED International Conference on Applied Simulation and Modelling, ASM 2009

Abstract
Legged robots allow the locomotion on terrains inaccessible to other type of vehicles because they do not need a continuous support surface. Different strategies have been adopted for the optimization of these systems, during their design and construction phases, and during their operation. Among the different optimization criteria followed by different authors, it is possible to find issues related to energy efficiency, stability, speed, comfort, mobility and environmental impact. Evolutionary strategies are a way to "imitate nature" replicating the process that nature designed for the generation and evolution of species. The objective of this paper is to present a genetic algorithm, running over a simulation application of legged robots, which allows the optimization of several parameters of the robot model and of its gaits, for different locomotion speeds.

2009

Programming-by-demonstration in the coworker scenario for SMEs

Autores
Pires, JN; Veiga, G; Araujo, R;

Publicação
INDUSTRIAL ROBOT-AN INTERNATIONAL JOURNAL

Abstract
Purpose - The purpose of this paper is to report a collection of developments that enable users to program industrial robots using speech, several device interfaces, force control and code generation techniques. Design/methodology/approach - The reported system is explained in detail and a few practical examples are given that demonstrate its usefulness for small to medium-sized enterprises (SMEs), where robots and humans need to cooperate to achieve a common goal (coworker scenario). The paper also explores the user interface software adapted for use by non-experts. Findings - The programming-by-demonstration (PbD) system presented proved to be very efficient with the task of programming entirely new features to an industrial robotic system. The system uses a speech interface for user command, and a force-controlled guiding system for teaching the robot the details about the task being programmed. With only a small set of implemented robot instructions it was fairly easy to teach the robot system a new task, generate the robot code and execute it immediately. Research limitations/implications - Although a particular robot controller was used, the system is in many aspects general, since the options adopted are mainly based on standards. It can obviously be implemented with other robot controllers without significant changes. In fact, most of the features were ported to run with Motoman robots with success. Practical implications - It is important to stress that the robot program built in this section was obtained without writing a single line of code, but instead just by moving the robot to the desired positions and adding the required robot instructions using speech. Even the upload task of the obtained module to the robot controller is commanded by speech, along with its execution/termination. Consequently, teaching the robotic system a new feature is accessible for any type of user with only minor training. Originality/value - This type of PbD systems will constitute a major advantage for SMEs, since most of those companies do not have the necessary engineering resources to make changes or add new functionalities to their robotic manufacturing systems. Even at the system integrator level these systems are very useful for avoiding the need for specific knowledge about all the controllers with which they work: complexity is hidden beyond the speech interfaces and portable interface devices, with specific and user-friendly APIs making the connection between the programmer and the system.

2009

Experiments with service-oriented architectures for industrial robotic cells programming

Autores
Veiga, G; Pires, JN; Nilsson, K;

Publicação
ROBOTICS AND COMPUTER-INTEGRATED MANUFACTURING

Abstract
Integration of equipment in industrial robot cells is to an increasing part involved with interfacing modern Ethernet technologies and low-cost mass produced devices, such as vision systems, laser cameras, force-torque sensors, soft-PLCs, digital pens, pocket-PCs, etc. This scenario enables integrators to offer powerful and smarter solutions, more adapted to small and medium enterprises (SMEs), capable of integrating process knowledge and interface better with humans. Nevertheless, programming all these devices efficiently requires too much specific knowledge about the devices, their hardware architectures and specific programming languages, details about system communication low-level protocols, and other tricky details at the system level. To address these issues, this paper describes and analyses two of the most interesting service-oriented architectures (SOA) available, which exhibit characteristics that are well adapted to industrial robotics cells. To compare, discuss and evaluate their programming features and applicability a test bed was specially designed, and the two SOA are fully implemented to program the test bed. Special focus is given to the way services are specified and to the orchestration tools used to manage system logic. The obtained results show clearly that using integrations schemes based on SOA reduces system integration time and are more adapted to industrial robotic cell system integrators.

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